**4. Active infective endocarditis**

Despite advances in the diagnosis and antibiotic treatment of infective endocarditis, aortic valve endocarditis is most commonly treated surgically by valve replacement in combination with antibiotics. For patients with aortic valve endocarditis, the choice of valve between bioprostheses, homografts and mechanical prostheses remains controversial. According to the ACC/AHA guidelines for management of patients with heart valve disease, valve repair should be preferred because of the risk of infection of prosthetic materials in patients with native valve endocarditis (Bonow, 2006). There is no specific recommendation for use of particular valve prosthesis. In a randomized study, patients with aortic valve endocarditis recieving bioprostheses have been found lower 5-year survival rate than patients recieving mechanical valves and it has been found no difference between patients receiving homografts and mechanical valves (Nguyen, 2010). Wos and colleagues showed that the risk of recurrent endocarditis was higher with bioprostheses than with mechanical valves (Wos, 1996). Guerra et al also found that the risk of endocarditis reinfection is very low with mechanical valves (Guerra, 2001). Homograft seems to be good choice in severe destructive prosthetic (Musci, 2010) or native (Klieverik, 2009) valve endocarditis with aorto-ventricular dehiscence caused by abscess. Petterson et al reported that the Ross operation is an attractive option in patients with aortic valve endocarditis in all age (Petterson, 1998).

#### **5. Prosthetic valve choice in prengnancy**

Native valve diseases and prosthetic valve disfunction are still the most important surgical indications in pregnant women requiring heart surgery (Weiss, 1998). Aortic valve diseases can become more symptomatic during pregnancy. A serious aortic stenosis is seen relatively rare in pregnancy. While transvalvular gradient is below 50 mmHg the possibility of heart failure during the pregnancy and delivery is low (Oakley, 2003). In case of aortic stenosis, fetal prognosis due to growth retardation, early delivery or low birth weight is deteriorated (Hameed, 2001; Malhotra 2004). For that reason, in case of asypmtomatic aortic stenosis, with an intervention before pregnancy the becoming the situation more complex can be prevented. As long as left ventricular sistolic function is not impaired aortic insufficiency can be well tolerated during pregnancy. On the other hand severe heart insufficiency can develop in patients with acute aortic failure or low EF (Oakley, 2003). There is not enough experience about the implementation of balloon aortic valvuloplasty during pregnancy. Furthermore, a permanent solution is not provided with this approach (Siu, 1997). However, these approaches can be used as a bridge before the delivery because of the maternal and fetal mortality risk due to serious aortic stenosis and if it is required, a surgical intervention can be applied after the delivery.

It was reported that in case of a development of a valve trombosis during pregnancy in patients with a previous mechanical valve replacement a replacement can be prevented with the addition of trombolytic treatment. However, it has to be known that some complications can be seen with the trombolytic treatment, the success rate is limited, recurrences can be

Other option is pulmonary autograft for aortic root replacement. In the study of Akhyari and colleagues, pulmonary autograft had no advantages over composite grafts regarding

Despite advances in the diagnosis and antibiotic treatment of infective endocarditis, aortic valve endocarditis is most commonly treated surgically by valve replacement in combination with antibiotics. For patients with aortic valve endocarditis, the choice of valve between bioprostheses, homografts and mechanical prostheses remains controversial. According to the ACC/AHA guidelines for management of patients with heart valve disease, valve repair should be preferred because of the risk of infection of prosthetic materials in patients with native valve endocarditis (Bonow, 2006). There is no specific recommendation for use of particular valve prosthesis. In a randomized study, patients with aortic valve endocarditis recieving bioprostheses have been found lower 5-year survival rate than patients recieving mechanical valves and it has been found no difference between patients receiving homografts and mechanical valves (Nguyen, 2010). Wos and colleagues showed that the risk of recurrent endocarditis was higher with bioprostheses than with mechanical valves (Wos, 1996). Guerra et al also found that the risk of endocarditis reinfection is very low with mechanical valves (Guerra, 2001). Homograft seems to be good choice in severe destructive prosthetic (Musci, 2010) or native (Klieverik, 2009) valve endocarditis with aorto-ventricular dehiscence caused by abscess. Petterson et al reported that the Ross operation is an attractive option in patients with aortic valve endocarditis in all

Native valve diseases and prosthetic valve disfunction are still the most important surgical indications in pregnant women requiring heart surgery (Weiss, 1998). Aortic valve diseases can become more symptomatic during pregnancy. A serious aortic stenosis is seen relatively rare in pregnancy. While transvalvular gradient is below 50 mmHg the possibility of heart failure during the pregnancy and delivery is low (Oakley, 2003). In case of aortic stenosis, fetal prognosis due to growth retardation, early delivery or low birth weight is deteriorated (Hameed, 2001; Malhotra 2004). For that reason, in case of asypmtomatic aortic stenosis, with an intervention before pregnancy the becoming the situation more complex can be prevented. As long as left ventricular sistolic function is not impaired aortic insufficiency can be well tolerated during pregnancy. On the other hand severe heart insufficiency can develop in patients with acute aortic failure or low EF (Oakley, 2003). There is not enough experience about the implementation of balloon aortic valvuloplasty during pregnancy. Furthermore, a permanent solution is not provided with this approach (Siu, 1997). However, these approaches can be used as a bridge before the delivery because of the maternal and fetal mortality risk due to serious aortic stenosis and if it is required, a surgical intervention

It was reported that in case of a development of a valve trombosis during pregnancy in patients with a previous mechanical valve replacement a replacement can be prevented with the addition of trombolytic treatment. However, it has to be known that some complications can be seen with the trombolytic treatment, the success rate is limited, recurrences can be

mid-term morbidity and mortality in aortic position (Akhyari, 2009).

**4. Active infective endocarditis** 

age (Petterson, 1998).

can be applied after the delivery.

**5. Prosthetic valve choice in prengnancy** 

seen after the treatment (Elkayam2005; Roudaut 2003). As the data about this topic is limited the complication rates seen in nonpregnant patients can be taken into consideration. A surgical treatment during pregnancy can be required in patients without benefits despite medical treatments and percutaneous approaches. Although the maternal mortality is below 3% for pregnant patients undergoing CPB with aortic valve replacement, fetal loss reaches 20% (Pomini 1996). Some strategies like avoiding hypotermia, providing enough perfusion pressure are recommended in order to decrease these adverse effects of CPB. Besides that, because of the effects of cardioplegia usage like hemodilution and hyperkalemia, recently some valve operation in beating heart also are reported (Tehrani 2004). The choice of valve type for valve replacement in pregnancy is similar to the choice criteria in young women patients. In a similar way it is difficult to make a decision about the valve choice because of the degeneration risk of the biological valves in young women and the requirement of anticoagulation for the mechanical valves, the fact that the trombosis of the mechanical valves during pregnancy can be a cause of mortality, and the limited data about how the homografts are influenced during pregnancy. However, the participation of the patient in the decision process has to be provided by discussing with the pregnant patient and informating her for all of the possible complications and frequencies. During the decision besides the current pregnancy, the expectation of a new pregnacy in future is also important (Elkayam2005). On the contrary to the results of the previous studies, recent studies have demonstrated that pregnancy does not cause a deterioration or calcification in biological valves (Reimold 2003).

#### **6. Prosthetic valve choice in young women**

Especially in the developing countries valve diseases requiring a surical intervention is seen frequently in young age group due to the fact that rheumatic valve diseases are not very uncommon. Although the valve repairement is the most ideal treatment method in young age group, in case of a serious impaired structure of the valve a repairement is not always possible. In that situation valve replacement is needed. A prothesis choice is still a controverisal issue in young patients needing prosthetic valve replacement (Solymar 1991; Trimn 2007). The reason is that all of the chosed prosthetic valves have their own advantages and disadvantages. That's why the decision has to be made according to the most suitable valve alternative for the patients' characteristics. The patient has to be informed about the advantages and disadvantages of the valve types in terms of possible complications. Thereafter, the patient has to be involved in the decision process. Young women have a different situation among the patients undergoing valve surgery because of the pregnancy possibility. The fact that the bioprothesis used in young age can be exposed to early degeneration because of the rapid body metabolism or the requirement of anticoagulants in patients with preference of mechanical prosthetic valves are situations which have to be evaluated seperately. As the valve lesion present before pregnancy will become more pronounced with the pregnancy, patients can undergo a comfortable period during the pregnancy with the intervention to the valve lesion in that period. In these approaches, along with the medical treatment support, when required, balloon-plasty is the first preference. By postponding of the sugical interventions during the pregnancy, maternal and fatal risk due to the surgery is tried to be prevented. Yet if there is no benefit although the applied medical treatment and percutaneous intervention, valve repairment or valve replacement is applied surgically. The main difficulty in that stage is the choice of the valve type which will be used.

Which Valve to Who: Prosthetic Valve Selection for Aortic Valve Surgery 45

Patients using mechanical valves can feel uncomfortable because of the valve sounds, are more frequently asked to come for outpatient visits and need more closed monitorization with blood tests. Besides that, the mechanical prosthetic valves are not degenerated by time. The usage of anticoagulants is essential. Some physiological changes are seen with pregnancy. Fibrinogen level can increase and reach to two folds levels than normally. As factors VII, VIII, IX, and XII are increasing in the third trimestre, antritrombin II level is decreasing. Duration of pregnancy, body composition and rapid fluid shifts were demonstrated as factors influencing the coagulation system. Blood volume, viscosity, intraabdominal pressure increase and venous compression also increases (Al-Lawati AA, 2002). As there is a presence of naturally hypercoagulable state the dose of the anticoagulant treatment should be kept higher. The rate of mechanical valve trombosis reaches 14% because of this hypercoagulable state (Abbas, 2005). A maternal mortality rate of 10% is seen in these patients (Weiss BM, 1998). On the other hand, complications due to high dose anticoagulants is seen more frequently too. The superiority of the biological valves was emphasized in the retrospective evaluations of the first generation mechanicalal valves in order to avoid the complications due to high dose anticoagulants (Jamieson, 1993; Cannegieter, 1994). However, the tendency to trombosis of the mechanicalal prosthetic

With the development of a new generation of mechanical valves, optimal anticoagulation doses were provided too. However, the usage of anticoagulants during pregnancy is still a controversial issue. Actually, as a common practice, after heparin usage in the first tremestre, warfarin treatment is used up to the expected delivery time, and then heparin is used instead again. Although there are centers accepting this procedure reliable, this subject is still a controversial subject because of the present complications (Salazar, 1996; Ismail, 1986; Pavankumar; 1988). For that reason there is no distinct concensus about the ideal anticoagulant treatment in terms of maternal and fetal prognosis. Warfarin is a good anticoagulant. But as it can pass placenta, fetal malformation, fetal loss and peripartum haemorrage can be seen in the organogenesis stage. These effects of warfarin were shown to be dose dependent [Oakley, 2003; Hanania, 2001). Although it is shown that when a 5 mg dose was not exceeded it is not a cause of embriopathy, it is known that it increases the rates of abortus. For that reason it is suggested that the embriopathy rates seen in the live births is relatively lower. Especially because of embriopathy occurring with warfarin usage between 6 and 12 weeks, a shifting heparin treatment is offered in this period (Iturbe-Alessio; 1986). As heparin is a large molecule and can not pass the placenta, negative effects on fetus is not expected. Additionally, heparin was not found to be associated with bleeding during the peripartum period (Noller, 1982; Iturbe-Alessio; 1986). For that reason warfarin treatment should be replaced with heparin treatment in the post 36 week period. A mortality rate of 1- 4% is seen in the pregnant patients with mechanicalal prosthetic valves, which is more commonly due to valve thrombosis (Chan, 2000; Elkayam, 2005) The usage of heparin during pregnancy was shown to be a cause of maternal tromboemboli states like occlusive prosthetic thrombosis, including fatal events (Sbarouni, 1994; Hanania, 1994; Salazar, 1996; Oakley, 2003). The usage of low molecule weight heparins is not recommended in the pregnancy period because of the difficulty in their monitorization and titration, and their close relationship with the tromboembolic events (Iturbe-Alessio, 1986; Salazar, 1996; Meschengieser 1999). Although under current conditions warfarin seems to be more appropriate treatment method because of the reduction in maternal complications, most female patients, when they are informed, do not want to use this drug because of its fetal

valves in that period was higher.

The biological grafts include heterografts, homografts and autografts. Among these prothesis, maximal clinical data exists about the porcine heterografts. Biological valves undergo some degeneration in every age and for that reason their long-term durability is influenced which results in a higher rate of valve reoperation (Brais 1985; Jamieson 2003; Gross 1998). In young patients this degeneration is seen more frequently because of the increased calcium turnover, fatigue-induced lesions and collagen degeneration, and discrete immunologic reaction (Berrebi 2001; Gross 1998; Salazar 1999; Badduke 1991; Sbarouni 1994). Additionally, in some studies it was suggested that the usage of biological valves in early periods results in increased rate of degeneration in pregnancy. Besides that, there are also studies demonstrating that the biological valves are not damaged during pregnancy due to the developments in the fixation technics of the first generation biological valves and the valve production technology (Jamieson 1995; North 1999; Salazar 1999). Interestingly, in a study showing that bioprosthesis are more rapidly degenerated during pregnancy, the survey rate of the patients with mechanical valves were found to be lower than those with biological valves (Robyn 1999). These rates were reported to be influenced by the pregnancy rate after the biological valve replacement (Lee 1994). The controversial results in different studies can be influenced by some factors like the inclusion of non-homogeneous populations, disregard of the age of patients, the time period between prosthesis implantation and gestation, and the condition of the prothesis before pregnancy, which avoids the correct evaluation of the data. Additionally, data about long-term follow up, especially in case of repeated pregnancies, is also unsufficient. Althougt there is no consensus about the influence of the pregnancy on biological valve degeneration, this possibility has to be told to the potential pregnant patient. The reason is that re-replacement is needed for the patients with degenerated biological valves. Especially the risks of such operations during pregnancy in terms of maternal and fetal prognosis has to be denoted. Fifty percent of the patients who undergone biological valve replacement in young age require a reoperation 10 years later. It means that almost all of these patients will undergo at least one re-operation during their life period (Elkayam 2005). The mortality rate following such a re-operation is reported as 3.8-8.7% (Jamieson 1995; Badduke 1991). Shaer et al. showed in their 18 years follow-up study that pregnancy has no additive contribution to the structural degeneration of biological valves. The importance of that study is that all of the patients included in the study have similar characteristic features (Fayez 2005). In studies comparing two different type heterografts used in young patients (Hancock and Carpentier-Edwards porcine bioprostheses), a structural valve deterioration in a rate of 50-70% in 10 years follow-up was demonstrated (Yum 1995; Jamieson 1988). Similarly, North et al. reported that structural valve deterioration in 10 years follow-up can be seen in high rates as 82% [preg9/5]. As it is seen the valve choice influences not only the possible complications but also the patient's survival. In a recent study about the usage of the last generation biological valves in young patients, it was shown that the valve degeneration is quite low and survival rates are distinctly high. These good results are suggested to be due to the usage of new fixation technics and the development of agents used for anti-mineralization (Carpentier 1995).

The biological valves are less thrombogenic than the mechanical valves. For that reason anticoagulation is not needed. However, tromboembolic complications due to biological valves, although rarely, are seen. They can be seen especially in the first days following valve replacement before the development of an endothelization. The annual tromboembolism risk following biological valve replacement is 0.7% (North 1999).

The biological grafts include heterografts, homografts and autografts. Among these prothesis, maximal clinical data exists about the porcine heterografts. Biological valves undergo some degeneration in every age and for that reason their long-term durability is influenced which results in a higher rate of valve reoperation (Brais 1985; Jamieson 2003; Gross 1998). In young patients this degeneration is seen more frequently because of the increased calcium turnover, fatigue-induced lesions and collagen degeneration, and discrete immunologic reaction (Berrebi 2001; Gross 1998; Salazar 1999; Badduke 1991; Sbarouni 1994). Additionally, in some studies it was suggested that the usage of biological valves in early periods results in increased rate of degeneration in pregnancy. Besides that, there are also studies demonstrating that the biological valves are not damaged during pregnancy due to the developments in the fixation technics of the first generation biological valves and the valve production technology (Jamieson 1995; North 1999; Salazar 1999). Interestingly, in a study showing that bioprosthesis are more rapidly degenerated during pregnancy, the survey rate of the patients with mechanical valves were found to be lower than those with biological valves (Robyn 1999). These rates were reported to be influenced by the pregnancy rate after the biological valve replacement (Lee 1994). The controversial results in different studies can be influenced by some factors like the inclusion of non-homogeneous populations, disregard of the age of patients, the time period between prosthesis implantation and gestation, and the condition of the prothesis before pregnancy, which avoids the correct evaluation of the data. Additionally, data about long-term follow up, especially in case of repeated pregnancies, is also unsufficient. Althougt there is no consensus about the influence of the pregnancy on biological valve degeneration, this possibility has to be told to the potential pregnant patient. The reason is that re-replacement is needed for the patients with degenerated biological valves. Especially the risks of such operations during pregnancy in terms of maternal and fetal prognosis has to be denoted. Fifty percent of the patients who undergone biological valve replacement in young age require a reoperation 10 years later. It means that almost all of these patients will undergo at least one re-operation during their life period (Elkayam 2005). The mortality rate following such a re-operation is reported as 3.8-8.7% (Jamieson 1995; Badduke 1991). Shaer et al. showed in their 18 years follow-up study that pregnancy has no additive contribution to the structural degeneration of biological valves. The importance of that study is that all of the patients included in the study have similar characteristic features (Fayez 2005). In studies comparing two different type heterografts used in young patients (Hancock and Carpentier-Edwards porcine bioprostheses), a structural valve deterioration in a rate of 50-70% in 10 years follow-up was demonstrated (Yum 1995; Jamieson 1988). Similarly, North et al. reported that structural valve deterioration in 10 years follow-up can be seen in high rates as 82% [preg9/5]. As it is seen the valve choice influences not only the possible complications but also the patient's survival. In a recent study about the usage of the last generation biological valves in young patients, it was shown that the valve degeneration is quite low and survival rates are distinctly high. These good results are suggested to be due to the usage of new fixation technics and the development of agents used for anti-mineralization

The biological valves are less thrombogenic than the mechanical valves. For that reason anticoagulation is not needed. However, tromboembolic complications due to biological valves, although rarely, are seen. They can be seen especially in the first days following valve replacement before the development of an endothelization. The annual tromboembolism

risk following biological valve replacement is 0.7% (North 1999).

(Carpentier 1995).

Patients using mechanical valves can feel uncomfortable because of the valve sounds, are more frequently asked to come for outpatient visits and need more closed monitorization with blood tests. Besides that, the mechanical prosthetic valves are not degenerated by time. The usage of anticoagulants is essential. Some physiological changes are seen with pregnancy. Fibrinogen level can increase and reach to two folds levels than normally. As factors VII, VIII, IX, and XII are increasing in the third trimestre, antritrombin II level is decreasing. Duration of pregnancy, body composition and rapid fluid shifts were demonstrated as factors influencing the coagulation system. Blood volume, viscosity, intraabdominal pressure increase and venous compression also increases (Al-Lawati AA, 2002). As there is a presence of naturally hypercoagulable state the dose of the anticoagulant treatment should be kept higher. The rate of mechanical valve trombosis reaches 14% because of this hypercoagulable state (Abbas, 2005). A maternal mortality rate of 10% is seen in these patients (Weiss BM, 1998). On the other hand, complications due to high dose anticoagulants is seen more frequently too. The superiority of the biological valves was emphasized in the retrospective evaluations of the first generation mechanicalal valves in order to avoid the complications due to high dose anticoagulants (Jamieson, 1993; Cannegieter, 1994). However, the tendency to trombosis of the mechanicalal prosthetic valves in that period was higher.

With the development of a new generation of mechanical valves, optimal anticoagulation doses were provided too. However, the usage of anticoagulants during pregnancy is still a controversial issue. Actually, as a common practice, after heparin usage in the first tremestre, warfarin treatment is used up to the expected delivery time, and then heparin is used instead again. Although there are centers accepting this procedure reliable, this subject is still a controversial subject because of the present complications (Salazar, 1996; Ismail, 1986; Pavankumar; 1988). For that reason there is no distinct concensus about the ideal anticoagulant treatment in terms of maternal and fetal prognosis. Warfarin is a good anticoagulant. But as it can pass placenta, fetal malformation, fetal loss and peripartum haemorrage can be seen in the organogenesis stage. These effects of warfarin were shown to be dose dependent [Oakley, 2003; Hanania, 2001). Although it is shown that when a 5 mg dose was not exceeded it is not a cause of embriopathy, it is known that it increases the rates of abortus. For that reason it is suggested that the embriopathy rates seen in the live births is relatively lower. Especially because of embriopathy occurring with warfarin usage between 6 and 12 weeks, a shifting heparin treatment is offered in this period (Iturbe-Alessio; 1986). As heparin is a large molecule and can not pass the placenta, negative effects on fetus is not expected. Additionally, heparin was not found to be associated with bleeding during the peripartum period (Noller, 1982; Iturbe-Alessio; 1986). For that reason warfarin treatment should be replaced with heparin treatment in the post 36 week period. A mortality rate of 1- 4% is seen in the pregnant patients with mechanicalal prosthetic valves, which is more commonly due to valve thrombosis (Chan, 2000; Elkayam, 2005) The usage of heparin during pregnancy was shown to be a cause of maternal tromboemboli states like occlusive prosthetic thrombosis, including fatal events (Sbarouni, 1994; Hanania, 1994; Salazar, 1996; Oakley, 2003). The usage of low molecule weight heparins is not recommended in the pregnancy period because of the difficulty in their monitorization and titration, and their close relationship with the tromboembolic events (Iturbe-Alessio, 1986; Salazar, 1996; Meschengieser 1999). Although under current conditions warfarin seems to be more appropriate treatment method because of the reduction in maternal complications, most female patients, when they are informed, do not want to use this drug because of its fetal

Which Valve to Who: Prosthetic Valve Selection for Aortic Valve Surgery 47

process of making a choice for the prosthetic valve, a comparison should be made according to the degeneration risk of biological valves, tromboemboli due to mechanicalal prosthetic valves and bleeding complications due to anticoagulants. In summary, every patient has to be evaluated individually in order to make a desicion what is the best for her or him. (Mihaljevic, 2005). All of these results should be shared with the patient before the

Sometimes a valve replacement because of valvular or non-valvular reasons is needed to be performed again. A valve replacement is made because of different reasons like the valve degeneration, calcification or valve thrombosis of the previously replaced prosthetic valve, endocarditis, dehicence, or pannus formation. In that situation, the selection of the prosthetic valve needed for the replacement should be made according to the individual characteristics. When in case of active prosthetic valve endocarditis tissue valve more resistant to infection is selected, age factor should be taken into consideration too. Especially a rapid degeneration in a patient with previously selected biological valve can be a cautionary signal that this situation can be eventuated again. A comprehensive information about the both prosthetic valve types should be given to the patient before the reoperation. Thereafter, the final decision about the valve choice should be taken together with the

Recently developed percutaneous aortic valve replacement can also be appropriate alternative for the reoperation. Especially it is an appropriate alternative for the patients in whom the reoperation is riskly because of comorbid situations (Fusari, 2009). With this new approach called as "valve-in-valve", trans-catheter stent valve is implanted percutaneously in the degenerated biological valve. The early results of this tecnique are promissing, but the long period results are not still known [Gotzmann, 2011, Fusari, 2009, Ye, 2007). At the same time, it should not be forgotten that complications like occlusion of the coronary ostiums, endocarditis, embolization of the prosthesis, iatrogenic aortic dissection can be seen (Tay,

Abbas AE, Lester SJ & Connolly H. (2005). Pregnancy and the cardiovascular system. *Int J* 

Akins CW, Buckley MJ, Daggett WM et al. (1998). Risk of reoperative valve replacement for failed mitral and aortic bioprostheses. *Ann Thorac Surg* 65:1545-1552. Akhyari P, Bara C, Kofidis T, Khaladj N, Haverich A & Klima U. (2009). Aortic root and ascending aortic replacement. Bentall or Ross Procedure? *In Heart J* 50:47-57. Al-Attar N, Himbert D, Descoutures F et al. (2009). Transcatheter Aortic Valve Implantation: Selection Strategy Is Crucial for Outcome. *Ann Thorac Surg* 87:1757-1763. Albertucci M, Wong K, Petrou M, et al. (1994). The use of unstented homograft valves for

Alexiou C, McDonald A, Langley SM, Dalrymple-Hay MJ, Haw MP & Monro JL. (2000).

aortic valve reoperations: Review of a twenty-three-year experience. *J Thorac* 

Aortic valve replacement in children: are mechanical prostheses a good option? *Eur* 

operation.

patient.

**7. References** 

**6.1 A valve selection for the reoperation** 

2011; Kukucka, 2011; Carnero-Alcázar 2010).

*Cardiovasc Surg* 107:152-161.

*J Cardiothorac Surg* 17:125-133.

*Cardiol* 98:179–189.

effects. Moreover, even in the second trimestre, they do not want to stop heparin and go on with heparin treatment (Evans, 1997; Yinon, 2009)

Yinon et al. evaluated the usage of low molecule weight heparin and aspirin in patients with mechanicalal prosthetic valve replacement who do not want to use warfarin during pregnancy because of its embriopathy risk. The study reported that even in patients followed-up with carefull monitorization the rate of the maternal cardiac and fetal complications is high and bleeding is seen (Yinon, 2009). Additionally, non-cardiac complication rates like postpartum bleeding was found to be as high as 13%, which is higher than it is reported in the previous studies.

In order to avoid these possible complications the effect of the anticoagulation therapy during pregnancy has to be closely monitorized. It is important to identify the most important strategy by transition between warfarin and heparin in the distinct periods of pregnancy.

Homografts can be an alternative for the young women at childbearing age. There is no evident data about the possible complications of this valve not needing an anticoagulation and its generation during pregnancy (Yacoub, 1995; Waszyrowski, 1997). However, some studies in the literature gave an idea. Robyn et al. showed that less degeneration is seen after the usage of homograft in comparison with biological prosthetic valve users and less requirement of reoperation is needed (Robyn 1999). Similarly, North et al. reported in a recent study that homografts are more resistant in comparison with bioprosthetic valves in 10 years follow-up and structural valve detorioration is developed more infrequently (72% vs. 18% ) (North 1999). It was shown that there was less structural failure requiring reoperation in homografts in comparison with biological grafts (Yum, 1995; Jamieson, 1988). Studies evaluating the effects of pregnancy on homografts are even more limited. Sadler et al. reported that 94% live births had eventuated in patients followed-up following homograft valve replacement and only in two patients a heart failure developed during pregnancy (Sadler, 2000). Although there are studies supporting these results, data about how the homograft are effected during pregnancy is still limited (Dyke, 2003). Prospective studies in future can suggest homografts as appropriate alternatives in young women.

Especially for young women who wants to get pregnant Ross procedure can be a good alternative because its perfect valve hemodynamics and not being thrombogenic [Al-Halees, 2002). However this opertaion is difficult in terms of technical aspect and as the operative mortality is reported as 2-13% in different studies it has to be performed in experienced centres (Rahimtoola, 2003; Takkenberg, 2002; Schmidtke 2003). Additionally, the effects of pregnancy on Ross procedure in not clear, as for homografts (Schmidtke, 2003; Dore,1997; Martin, 2003). Dore and Somerville (Dore,1997) reported in their study made with small number of patients that serious complications like mortality, trombo-embolic event or bleeding was not observed in patients who underwent Ross procedure. But, as there is not enough data for this surgical technique, its usage in young women who have potential for becoming pregnant is not still widespread.

As a conclusion, the optimal prosthetic cardiac valve for the women at childbearing age is still a controversial subject. The reason is that there is no consensus about the effects of anticoagulants and side effects in the research studies. The degenerative effects of biological valves on pregnancy is not clearly known. There are studies showing the effects of trombolytic studies even in trombosis of mechanicalal prosthetic valves. The reoperation carried out after the degeneration of biological valves was reported to be more safely performed. As it is seen, these study results give different messages. For that reason, in a process of making a choice for the prosthetic valve, a comparison should be made according to the degeneration risk of biological valves, tromboemboli due to mechanicalal prosthetic valves and bleeding complications due to anticoagulants. In summary, every patient has to be evaluated individually in order to make a desicion what is the best for her or him. (Mihaljevic, 2005). All of these results should be shared with the patient before the operation.

#### **6.1 A valve selection for the reoperation**

46 Aortic Valve Surgery

effects. Moreover, even in the second trimestre, they do not want to stop heparin and go on

Yinon et al. evaluated the usage of low molecule weight heparin and aspirin in patients with mechanicalal prosthetic valve replacement who do not want to use warfarin during pregnancy because of its embriopathy risk. The study reported that even in patients followed-up with carefull monitorization the rate of the maternal cardiac and fetal complications is high and bleeding is seen (Yinon, 2009). Additionally, non-cardiac complication rates like postpartum bleeding was found to be as high as 13%, which is higher

In order to avoid these possible complications the effect of the anticoagulation therapy during pregnancy has to be closely monitorized. It is important to identify the most important strategy by transition between warfarin and heparin in the distinct periods of

Homografts can be an alternative for the young women at childbearing age. There is no evident data about the possible complications of this valve not needing an anticoagulation and its generation during pregnancy (Yacoub, 1995; Waszyrowski, 1997). However, some studies in the literature gave an idea. Robyn et al. showed that less degeneration is seen after the usage of homograft in comparison with biological prosthetic valve users and less requirement of reoperation is needed (Robyn 1999). Similarly, North et al. reported in a recent study that homografts are more resistant in comparison with bioprosthetic valves in 10 years follow-up and structural valve detorioration is developed more infrequently (72% vs. 18% ) (North 1999). It was shown that there was less structural failure requiring reoperation in homografts in comparison with biological grafts (Yum, 1995; Jamieson, 1988). Studies evaluating the effects of pregnancy on homografts are even more limited. Sadler et al. reported that 94% live births had eventuated in patients followed-up following homograft valve replacement and only in two patients a heart failure developed during pregnancy (Sadler, 2000). Although there are studies supporting these results, data about how the homograft are effected during pregnancy is still limited (Dyke, 2003). Prospective studies in future can suggest homografts as appropriate alternatives in young women. Especially for young women who wants to get pregnant Ross procedure can be a good alternative because its perfect valve hemodynamics and not being thrombogenic [Al-Halees, 2002). However this opertaion is difficult in terms of technical aspect and as the operative mortality is reported as 2-13% in different studies it has to be performed in experienced centres (Rahimtoola, 2003; Takkenberg, 2002; Schmidtke 2003). Additionally, the effects of pregnancy on Ross procedure in not clear, as for homografts (Schmidtke, 2003; Dore,1997; Martin, 2003). Dore and Somerville (Dore,1997) reported in their study made with small number of patients that serious complications like mortality, trombo-embolic event or bleeding was not observed in patients who underwent Ross procedure. But, as there is not enough data for this surgical technique, its usage in young women who have potential for

As a conclusion, the optimal prosthetic cardiac valve for the women at childbearing age is still a controversial subject. The reason is that there is no consensus about the effects of anticoagulants and side effects in the research studies. The degenerative effects of biological valves on pregnancy is not clearly known. There are studies showing the effects of trombolytic studies even in trombosis of mechanicalal prosthetic valves. The reoperation carried out after the degeneration of biological valves was reported to be more safely performed. As it is seen, these study results give different messages. For that reason, in a

with heparin treatment (Evans, 1997; Yinon, 2009)

than it is reported in the previous studies.

becoming pregnant is not still widespread.

pregnancy.

Sometimes a valve replacement because of valvular or non-valvular reasons is needed to be performed again. A valve replacement is made because of different reasons like the valve degeneration, calcification or valve thrombosis of the previously replaced prosthetic valve, endocarditis, dehicence, or pannus formation. In that situation, the selection of the prosthetic valve needed for the replacement should be made according to the individual characteristics. When in case of active prosthetic valve endocarditis tissue valve more resistant to infection is selected, age factor should be taken into consideration too. Especially a rapid degeneration in a patient with previously selected biological valve can be a cautionary signal that this situation can be eventuated again. A comprehensive information about the both prosthetic valve types should be given to the patient before the reoperation. Thereafter, the final decision about the valve choice should be taken together with the patient.

Recently developed percutaneous aortic valve replacement can also be appropriate alternative for the reoperation. Especially it is an appropriate alternative for the patients in whom the reoperation is riskly because of comorbid situations (Fusari, 2009). With this new approach called as "valve-in-valve", trans-catheter stent valve is implanted percutaneously in the degenerated biological valve. The early results of this tecnique are promissing, but the long period results are not still known [Gotzmann, 2011, Fusari, 2009, Ye, 2007). At the same time, it should not be forgotten that complications like occlusion of the coronary ostiums, endocarditis, embolization of the prosthesis, iatrogenic aortic dissection can be seen (Tay, 2011; Kukucka, 2011; Carnero-Alcázar 2010).

## **7. References**


Which Valve to Who: Prosthetic Valve Selection for Aortic Valve Surgery 49

Bonow RO, Carabello BA, Chatterjee K, et al. (2008). 2008 Focused update incorporated into

Borger MA, Carson SM, Ivanov J et al. (2005). Stentless Aortic Valves are Hemodynamically

Brais M, Bedard P, Goldstein W, et al. (1985). Ionescu-Shiley pericardial xenografts and

Brinkman WT, Williams WH, Guyton RA, Jones EL & Craver JM. (2002). Valve replacement

Cannegieter SC, Rosendaal FR & Briet E. (1994). Thromboembolic and bleeding

Carnero-Alcázar M, Maroto Castellanos LC, Carnicer JC & Rodríguez Hernández JE. (2010).

Carpentier SM, Carpentier AF, Chen L, Shen M, Quintero LJ & Witzel TH. (1995). Calcium

Carrier M, Pellerin M, Perrault LP et al. (2001). Aortic Valve Replacement With Mechanical and Biologic Prostheses in Middle-Aged Patients. *Ann Thorac Surg* 71:S253-256. Carr-White GS, Kilner PJ, Hon JK, Rutledge T, Edwards S, Burman ED, Pennell DJ & Yacoub

Champsaur G, Robin J, Tronc F, Curtil A, Ninet J, Sassolas F, Vedrinne C & Bozio A. (1997).

Chan V, Jamieson E, Fleisher AG, Denmark D, Chan F & Germann E. (2006). Valve

Chan WS, Anand S & Ginsberg JS. (2000). Anticoagulation of pregnant women with

Clavel MA, Webb JG, Pibarot P, et al. (2009). Comparison of the hemodynamic performance

114:e84–231.

Cardiol 52:e1-142.

*Thorac Surg* 74:37-42.

89:635– 641.

11(3):252-253.

160:191–196.

Study. *Ann Thorac Surg* 80:2180-2185.

leaching. *Ann Thorac Surg* 60:S332–S338.

*J Heart Valve Dis* 8:376-383.

*Eur J Cardiothorac Surg* 11:117-122.

bioprostheses. *Ann Thorac Surg* 81:857-862.

stenosis. *J Am Coll Cardiol* 53:1883–1891.

follow up of up to 6 years. *Ann Thorac Surg* 39:105-111.

Angiography and Interventions and the Society of Thoracic Surgeons. *Circulation*

the ACC/AHA 2006 Guidelines for management of patients with valvular heart disease. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to revise the 1998 guidelines for management of patients with valvular heart desease). Endorsed by the Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Anjiography and Interventions, and Society of Thoracic Surgeons. J Am Coll

Superior to Stented Valves During Mid-Term Follow-Up: A Large Retrospective

in patients on chronic dialysis: Implications for valve prosthesis selection. *Ann* 

complications in patients with mechanical heart valve prostheses. *Circulation*

Transapical aortic valve prosthetic endocarditis. *Interact Cardiovasc Thorac Surg*

mitigation in bioprosthetic tissues by iron pretreatment: the challenge of iron

MH. (2001). Incidence, location, pathology, and significance of pulmonary homograft stenosis after the Ross operation. *Circulation* 104 (12 Suppl 1):I16-20. Caus T, Albertini JN, Chi Y, Collart F, Monties JR & Mesana T. Multiple valve replacement

increases the risk of reoperation for structural degeneration of bioprostheses.

Mechanical valve in aortic position is a valid option in children and adolescents.

replacement surgery in end-stage renal failure: Mechanical prostheses versus

mechanical heart valves: a systematic review of the literature. *Arch Intern Med*

of percutaneous and surgical bioprostheses for the treatment of severe aortic


Al-Halees Z, Pieters F, Qadoura F, Shahid M, Al-Amri M & Al-Fadley F. (2002). The Ross

Al-Lawati AA, Venkitraman M, Al-Delaime T & Valliathu J. (2002). Pregnancy and

Alsoufi B, Manlhiot C, McCrindle BW, Canver CC, Sallehuddin A, Al-Oufi S, Joufan M &

Bach, DS, Sakwa MP, Goldbach M, Petracek MR, Emery RW & Mohr FW. (2002).

Bach DS, Kon ND, Dumesnil JG, et al. (2005). Ten year outcome after aortic valve

Bauer F, Eltchaninoff H, Tron C, et al. (2004). Acute improvement in global and regional left

Ben Ismail M, Abid F, Trabeisi S, Tarktak M, Fekih M. (1986). Cardiac valve prostheses, and

Bentall H, De Bono A. (1968). A Technique for complete replacement of the ascending aorta.

Berrebi AJ, Carpentier SM, Phan KP, Nguyen VP, Chauvaud SM & Carpentier A. (2001).

Bonow RO, Carabello BA, deLeon AC Jr, et al. (1998). Guidelines for the management of

Bonow RO, Carabello BA, Chatterjee K, et al. (2006). ACC/AHA2006 practice guidelines for

Bonow RO, Carabello B, Chatterjee K, et al. (2006). ACC/AHA 2006 guidelines for the

surgery: a review of evidence. *Eur J Cardiothorac Surg* 25:304–311.

mechanical aortic valve. *Ann Thorac Surg* 74:2003-2009.

for aortic stenosis. *J Thorac Cardiovasc Surg* 131:883-888.

pregnancy anticoagulation. *Br Heart J* 55:101–105.

Guidelines. *Circulation* 98:1949–1984.

*Thorax* 23:338-339.

with symptomatic aortic stenosis. *Circulation* 110: 1473–1476.

young population. *Ann Thorac Surg* 71(5 Suppl.):S353—355.

Force on Practice Guidelines. *J Am Coll Cardiol* 48:598-675.

*Cardiovasc Surg* 123:437– 441.

*Cardiothorac Surg.* 22:223–227.

procedure is the procedure of choice for congenital aortic valve disease. *J Thorac* 

mechanical heart valves replacement; dilemma of anticoagulation. *Eur J* 

Al-Halees Z. (2009) Aortic and mitral valve replacement in children: is there any role for biologic and bioprosthetic substitutes? *Eur J Cardiothorac Surg* 36:84-90. Anselmi A, Abbate A, Girola F, Nasso G, Biondi-Zoccai GG, Possati G & Gaudino M. (2004).

Myocardial ischemia, stunning, inflammation, and apoptosis during cardiac

Hemodynamics and early clinical performance of the St. Jude medical regent

replacement with the Freestyle stentless bioprosthesis. *Ann Thorac Surg* 80:480-487. Badduke BR, Jamieson WR, Miyagishima RT, et al. (1991). Pregnancy and childbearing in a population with biologic valvular prostheses. *J Thorac Cardiovasc Surg* 102:179-186. Bakhtiary F, Schiemann M, Dzemali O, et al. (2006). Stentless bioprostheses improve

postoperative coronary flow more than stented prostheses after valve replacement

ventricular systolic function after percutaneous heart valve implantation in patients

Results of up to 9 years of high-temperature-fixed valvular bioprostheses in a

patients with valvular heart disease: executive summary. A report of the American College of Cardiology / American Heart Association Task Force on Practice

the management of patients with valvular heart disease: Executive summary: A report of the American College of Cardiology/American Heart Association Task

management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (writing committee to revise the 1998 Guidelines for the Management of Patients With Valvular Heart Disease): developed in collaboration with the Society of Cardiovascular Anesthesiologists: endorsed by the Society for Cardiovascular Angiography and Interventions and the Society of Thoracic Surgeons. *Circulation* 114:e84–231.


Which Valve to Who: Prosthetic Valve Selection for Aortic Valve Surgery 51

Guerra JM, Tornos MP, Permanyer-Miralda G, et al. (2001). Long term results of mechanical prostheses for treatment of active infective endocarditis. Heart 86:63-68. Hameed A, Karaalp IS, Tummala PP, et al. (2001). The effect of valvular heart disease on maternal and fetal outcome during pregnancy. *J Am Coll Cardiol* 37:893–899. Hammermeister K, Sethi GK, Henderson WG, Grover FL, Oprian C & Rahimtoola SH.

Hanania G. (2001). Management of anticoagulants during pregnancy. *Heart* 86:125–126. Hanania G, Thomas D, Michel PL, et al. (1994). Pregnancy and prosthetic heart valves: a French cooperative retrospective study of 155 cases. *Eur Heart J* 15:1651–1658. Harken DE, Soroff HS, Taylor WJ, et al. Partial and complete prostheses in aortic

Hart RG, Benavente O, McBride R & Pearce LA. (1999). Antithrombotic therapy to prevent

Hassanein W, Albert A, Florath I, Hegazy YY, Rosendahl U, Bauer S & Ennker J. (2007).

Ibrahim M, Cleland J, O'Kane H, Gladstone D, Mullholland C & Craig B. (1994). St Jude

Iturbe-Alessio I, Fonseca MC, Mutchinik O, Santos MA, Zajarias A & Salazar E. Risks of

Jamieson WR. (1993). Modern cardiac valve devices: bioprostheses and mechanical

Jamieson WRE, Burr LH, Miyagishima RT, et al. (2003). Reoperation for bioprosthetic aortic structural failure risk assessment. *Eur J Cardiothorac Surg* 24:873-878. Jamieson WRE, Miller DC, Akims CW, et al. (1995). Pregnancy and bioprostheses: influence of structural valve deterioration. *Ann Thorac Surg* 60 Suppl:S282–S287. Jamieson WR, Burr LH, Miyagishima RT, et al. (1995). Structural deterioration in Carpentier-

Jamieson WRE, Rosado LJ, Munro AI, et al. (1988). Carpentier-Edwards standard porcine

Jilaihawi H, Chin D, Spyt T, et al. (2010). Prosthesis-patient mismatch after transcatheter

Johansson M, Nozohoor S, Kimblad PO, Harnek J, Olivecrona GK & Sjögren J. (2011).

on the blood flow in bypass grafts. *Eur J Cardiothorac Surg* 31:391-396. Herzog CA, Ma JZ & Collins AJ. (2002). Long-term survival of dialysis patients in the United

Medical prosthesis in children. *J Thorac Cardiovasc Surg* 108:52-56.

stroke in patients with atrial fibrillation: a meta-analysis. *Ann Intern Med* 131: 492-

Concomitant aortic valve replacement and coronary bypass: the effect of valve type

States with prosthetic heart valves: should ACC/AHA practice guidelines on valve

anticoagulant therapy in pregnant women with artificial heart valves. *N Engl J Med*

Edwards standard and supraannular porcine bioprostheses. *Ann Thorac Surg* 60(2

bioprostheses: primary tissue failure (structure valve deterioration) by age groups.

aortic valve implantation with th Medtronic-Corevalve bioprosthesis. *Eur Heart J*

Transapical Versus Transfemoral Aortic Valve Implantation: A Comparison of

insufficiency. (1960). *J Thorac Cardiovasc Surg* 40:744-762.

selection be modified? *Circulation* 105:1336–41.

prostheses: state of the art. *J Card Surg* 8:89 –98.

Survival and Safety. *Ann Thorac Surg* 91:57-63.

*Cardiol* 36:1152-1158.

1986;315:1390-1393.

Suppl):S241-247.

31:857-864.

*Ann Thorac Surg* 46:155– 162.

501.

(2000). Outcomes 15 years after valve replacement with a mechanical versus a bioprosthetic valve: Final report of the veterans affairs randomized trial. *J Am Coll* 


Cosgrove DM, Lytle BW, Taylor PC, et al. (1995). The Carpentier-Edwards pericardial aortic

Cribier A, Eltchaninoff H, Tron C, et al. (2006). Treatment of calcific aortic stenosis with the

David TE, Omran A, Ivanov J, Armstrong S, de Sa MP, Sonnenberg B & Webb G. (2000).

De Santo LS, Romano G, Della Corte A, et al. (2005). Mitral mechanical replacement in

Del Rizzo DI, Goldman BS, Joyner CP, et al. (1994). Initial clinical experience with the

Desai MD, Christakis GT. (2008). Bioprosthetic Aortic Valve Replacement: Stented

Dore A & Sommerville J. (1997). Pregnancy in patients with pulmonary autograft valve

Dyke & Igic. (2003). Management of Prosthetic Heart Valve Anticoagulation in Pregnancy.

El-Hamamsy I, Eryigit Z, Stevens LM, et al. (2010). Long-term outcomes after autograft

Elkayam U. (2005). Valvular heart disease and pregnancy. Part II: Prosthetic valves*. J Am* 

El SF, Hassan W, Latroche B, et al. (2005). Pregnancy has no effect on the rate of structural

Emery RW, Krogh CC, Arom KV et al. (2005). The St. Jude Medical Cardiac Valve

Florath I, Albert A, Rosendahl U, Alexander T, Ennker IC & Ennker J. (2005). Mid term

Fusari M, Alamanni F, Bona V, et al. (2009). Transcatheter aortic valve implantation in the operating room: early experience. *J Cardiovasc Med (Hagerstown)* 10(5):383-393. Gatzoulis MA. (1999). Ross procedure: the treatment of choice for aortic valve disease? *Int J* 

Gotzmann M, Bojara W, Lindstaedt M, et al. (2011). One-year results of transcatheter aortic

Gross C, Klima U, Mair R & Brücke P. (1998). Aortic homografts versus mechanical valves in

mechanical versus stentless biological valves. *Heart* 91:1023–1029.

percutaneous heart valve: mid-term follow-up from the initial feasibility studies:

Dilation of the pulmonary autograft after the Ross procedure. *J Thorac Cardiovasc* 

young rheumatic women: analysis of long-term survival, valve-related complications, and pregnancy outcomes over a 3707-patient-year follow-up.

Pericardial and Porcine Valves, In: *Cardiac Surgery in the Adult,* Cohn LH. pp. 877,

versus homograft aortic root replacement in adults with aortic valve disease: a

deterioration of bioprosthetic valves: Long-term 18-year follow up results. *J Heart* 

Prosthesis: A 25-Year Experience With Single Valve Replacement. *Ann Thorac Surg* 

outcome and quality of life after aortic valve replacement in elderly people:

valve implantation in severe symptomatic aortic valve stenosis. *Am J Cardiol*

aortic valve replacement in young patients: a retrospective study. *Ann Thorac Surg*

valve. Ten-year results. *J Thorac Cardiovasc Surg* 110:651-662.

the French experience. *J Am Coll Cardiol* 47:1214–1223.

Toronto stentless porcine valve. *J Card Surg* 9:379-385.

*Surg* 119:210-220.

*J Thorac Cardiovasc Surg* 130:13-19.

McGraw-Hill Companies, New York.

replacement. *Eur Heart J* 18:1659–1662.

randomised controlled trial. *Lancet* 376:524-531.

*ACC Current Journal Review* 17-22.

*Coll Cardiol* 46:403–410.

*Valve Dis* 14:481-485.

*Cardiol* 71:205-206.

107(11):1687-1692.

66(6 Suppl):S194-S197.

79:776-783.


Which Valve to Who: Prosthetic Valve Selection for Aortic Valve Surgery 53

Lupinetti FM, Duncan BW, Lewin M, Dyamenahalli U & Rosenthal GL. (2003). Comparison

Malhotra M, Sharma JB, Tripathii R, Arora P & Arora R. (2004). Maternal and fetal outcome

Martin TC, Idahosa V, Ogunbiyi A, Fevrier-Roberts G & Winter A. (2003). Successful

Masters RG, Haddad M, Pipe AL, Veinot JP & Mesana T. (2004). Clinical outcomes with the

Mazzitelli D, Guenther T, Schreiber C, Wottke M, Michel J & Meisner H. (1998). Aortic valve

Meschengieser SS, Fondevila CG, Santarelli MT & Lazzari MA. (1999). Anticoagulation in pregnant women with mechanical heart valve prostheses. *Heart* 82:23-26. Mihaljevic T, Paul S, Leacche M, Rawn JD, Cohn LH & Byrne JG. (2005). Valve replacement

Milano AD, Blanzola C, Mecozzi G, D'Alfanzo A, De Carlo M, Nardi C & Bartolotti U.

Mistiaen WP, Cauwelaert PV, Muylaert P, Wuyts F, Harrisson F & Bortier H. (2004). Effects

Monson BK, Wickstrom PH, Haglin JJ, Francis G, Comty CM & Helseth MK. (1980). Cardiac operation and end stage renal disease. Ann Thorac Surg 30:267–272. Musci M, Hübler M, Amiri A, et al. (2010). Surgical treatment for active infective prosthetic

Nakai S, Akiba T, Kazama J, et al. (2008). Effects of serum calcium, phosphorus, and intact

Ngaage AL, Schaff HV, Barnes SA et al. (2006). Prognostic implications of preoperative atrial

Nguyen DT, Delahaye F, Obadia JF, et al. (2010). Aortic valve replacement for active

Nicks R, Cartmill T & Bernstein L. (1970). Hypoplasia of the aortic root. *Thorax* 25:339-346. North RA, Sadler L, Stewart AW, McCowan LM, Kerr AR & White HD. 1999. Long-term

Oakley C, Child A, Iung B, Presbitero P & Tornos P. (2003). Task Force on the management

for concomitant arrhythmia surgery? *Ann Thorac Surg 82:1392-1399.*

mechanical prostheses. *Eur J Cardiothorac Surg* 37:1025-1032.

replacements. *Circulation* 99:2669–2676.

diseases during pregnancy. *Eur Heart J* 24:761–781.

in valvular heart disease. *Int J Gynaecol Obstet* 84:11–16.

rheumatic aortic valve insufficiency. *West Indian Med J* 52:62– 64.

Hancock II bioprosthetic valve. *Ann Thorac Surg* 78:832-836.

*Surg* 126:240-246.

*Valve Dis* 151-1577.

*Ann Thorac Surg* 72:33-38.

*Ther Apher Dial* 12: 49–54.

571.

1597.

38:528-538.

of autograft and allograft aortic valve replacement in children. *J Thorac Cardiovasc* 

pregnancy and delivery after pulmonary autograft operation (Ross procedure) for

replacement in children: are we on the right track? *Eur J Cardiothorac Surg* 13:565-

in women of childbearing age: influences on mother, fetus and neonate. *J Heart* 

(2001). Hemodynamic performance of stented and stentless aortic bioprostheses.

of prior malignancy on survival after cardiac surgery. *Ann Thorac Surg* 77:1593-

valve endocarditis: 22-year single-centre experience. Eur J Cardiothorac Surg

parathyroid hormone levels on survival in chronic hemodialysis patients in Japan.

fibrillation in patients undergoing aortic valve replacement: Is there an argument

endocarditis: 5-year survival comparison of bioprostheses, homografts and

survival and valve-related complications in young women with cardiac valve

of cardiovascular diseases during pregnancy of the European Society of Cardiology. Expert consensus document on management of cardiovascular


Kalkat MS, Edwards MB, Taylor KM & Bonser RS. (2007). Composite aortic valve graft

Kaplon RJ, Cosgrove DM, Gillinov AM, Lytle BW, Blackstone EH & Smedira NG. (2000).

Kazama JJ. (2007). Japanese Society of Dialysis Therapy treatment guidelines for secondary

Khan SS, Trento A, DeRobertis M, et al. (2001). Twenty-year comparison of tissue and mechanical valve replacement. *J Thorac Cardiovasc Surg* 122):257-269. Kimata N, Miwa N, Otsubo S, et al. (2007). Achievement of the Japanese Society for Dialysis

Klieverik LMA, Yacoup MH, Edwards S, et al. Surgical treatment of actice native aortic

Kogan A, Medalion B, Kornowski R, et al. (2008). Cardiac surgery in patients on chronic hemodialysis: short and long-term survival. *Thorac Cardiovasc Surg* 56:123–127. Kolh P, Kerzmann A, Honore C, Comte L & Limet R. (2007). Aortic valve surgery in

Kukucka M, Pasic M, Dreysse S & Hetzer R. (2011). Delayed subtotal coronary obstruction

Kunihara T, Schmidt K, Glombitza P, Dzindzibadze V, Lausberg H & Schafers HJ. (2006).

Lamberti JJ, Wainer BH, Fisher KA, Karunaratne HB & Al- Sadir J. (1978). Calcific stenosis of

Lanefeld CS & Goldman L. (1989). Major bleeding in outpatients treated with warfarin:

Langley SM, McGuirk SP, Chaudhry MA, Livesey SA, Ross JK & Monro JL. (1999). Twenty-

Leavitt BJ, Baribeau YR, DiScipio AW, et al. (2009). Outcomes of patients of undergoing

Lee CW, Wu CC, Lin PY, Hsieh FJ & Chen HY. (1994). Pregnancy following cardiac

Lucke JC, Samy RN, Atkins BZ, et al. (1997). Results of valve replacement with mechanical

Lupinetti F, Warner J, Jones TK & Herndon P. (1997). Comparison of human tissues and

200 patients. Semin Thorac Cardiovasc Surg 11(4 Suppl 1):28-34.

prosthetic valve replacement. *Obstet Gynecol* 83:353– 6.

the porcine heterograft. Ann Thorac Surg 28:28–32.

hyperparathyroidism. *Ther Apher Dial* 11(suppl 1):S44–47.

university center result. *Ther Apher Dial* 11(suppl 1):S62–66.

301-I-306.

88:1814-1821.

60.

132.

325.

*Cardiothorac Surg* 31:600-606.

analysis. 82:1379-1384.

120(suppl 1):S155-S162.

*Med* 87:147–152.

survival. *Ann Thorac Surg* 70:438–441.

replacement. Mortality outcomes in a national registry. *Circulation* 116(Suppl I): I-

Cardiac valve replacement in patients on dialysis: Infl uence of prosthesis on

Therapy guideline targets for mineral metabolism measures: One Japanese

valve endocarditis with allografts and mechanical prostheses. *Ann Thorac Surg* 

octogenarians: predictive factors for operative and long-term results. *Eur J* 

after transapical aortic valve implantation. *Interact Cardiovasc Thorac Surg* 12(1):57-

Root replacement using stentless valves in the small aortic root: A propensity score

incidence and prediction by factors known at the start of outpatient therapy. *Am J* 

year follow-up of aortic valve replacement with antibiotic sterilized homografts in

concomitant aortic and mitral valve surgery in Northern New England. Circulation

and biological prosthesis in chronic renal dialysis patients. *Ann Thorac Surg* 64:129-

mechanical prostheses for aortic valve replacement in children. *Circulation* 96:321-


Which Valve to Who: Prosthetic Valve Selection for Aortic Valve Surgery 55

Schmidtke C, Stierle U, Sievers HH & Graf B. (2003). The Ross procedure (pulmonary

Siebenhofer A, Berghold A & Sawicki PT. (2004). Systematic review of studies of self-

Silberman S, Shaheen J, Merin O, et al. (2001). Exercise hemodynamics of aortic prostheses:

Silberman S, Oren A, Dotan M, Merin O, Fink D, Deeb M & Bitran D. (2008). Aortic valve

Siu SC, Sermer M, Harrison DA, et al. (1997). Risk and predictors for pregnancy-related complications in women with heart disease. *Circulation* 96:2789–2794. Solymar L, Rao PS, Mardini MK, Fawzy ME & Guinn G. (1991). Prosthetic valves in children

Stassano P, Di Tommaso L Monaco M, et al. (2009). Aortic valve replacement: a prospective

Stewart S, Hart CL, Hole DJ & McMurray JJ. (2002). A populationbased study of the long-

Takaseya T, Kawara T, Tokunaga S, Kohno M, Oishi Y & Morita S. (2007). Aortic valve

Takkenberg JJ, Dossche KM, Hazekamp MG, et al. (2002). Report of the Dutch experience with the Ross procedure in 343 patients. *Eur J Cardio Thorac Surg* 22:70 –77. Takkenberg JJ, van Herwerden LA, Eijkemans MJ, Bekkers JA & Bogers AJ. (2002). Evolution

Takkeberg JJ, van Herwerden LA, Galema TW, Bekkers JA, Kleyburg-Linkers VE, Eijkemans

Tay EL, Gurvitch R, Wijeysinghe N, et al. (2011). Outcome of patients after transcatheter

Tehrani H, Masroor S, Lombardi P, Rosenkranz E & Salerno T. (2004). Beating heart aortic

Thourani VH, Myung R, Kilgo P, et al. (2008). Long-term outcomes after isolated aortic

Thourani VH, Sarin EL, Keeling WB, et al. (2011). Long-term survival for patients with

Trimn J, Hung L & Rahimtoola SH. (2007). Prosthetic heart valves and pregnancy, In: *Heart* 

valve replacement in octogenarians: a modern perspective. *Ann Thorac Surg*

preoperative renal failure undergoing bioprosthetic or mechanical valve

*Disease in Pregnancy,* Oakley C, Warnes C. pp:104 –121, Blackwell Publishers,

aortic valve embolization. *JACC Cardiovasc Interv* 4(2):228-34.

valvereplacement in a pregnant patient. *J Card Surg* 19:57-58.

replacement. *Ann Thorac Surg* 91:1127-1134.

management of oral anticoagulation. *Thromb Haemost* 91:225-32.

and adolescents. *Am Heart J* 121(2 Pt.1):557-568.

Renfrew/Paisley study. Am J Med 113:359–364.

elderly patients. Ann Thorac Surg 83:2050-2053.

70 years, *J Am Coll Cardiol* 54;1862–1868.

*Cardiothorac Surg* 21:683-691.

*Dis* 15:100-106.

86:1458-1464.

London.

128:1759–1764.

*Surg* 72:1217-1221.

23:299-306.

autograft) as an alternative for aortic valve replacement. *Dtsch Med Wochenschr*

Comparison between stentless bioprostheses and mechanical valves. *Ann Thorac* 

replacement: choice between mechanical valves and bioprostheses. *J Card Surg*

randomized evaluation of mechanical versus biological valves in patients ages 55 to

term risks associated with atrial fibrillation: 20-year follow-up of the

replacement with 17-mm St. Jude medical prostheses for a small aortic root in

of allograft aortic valve replacement over 13 years: results of 275 procedures. *Eur J* 

MJ & Bogers AJ. (2006). Serial echocardiographic assessment of neo-aortic regurgitation and root dimensions after the modified Ross procedure. *J Heart Valve* 


Pavankumar P, Venugopal P, Kaul U, Lyer KS, Sas B & Sampathkumar A. (1988). Pregnancy

Petterson G, Tingleff J & Joyce FS. (1998). Treatment of aortic valve endocarditis with the

Pomini F, Mercogliano D, Cavalletti C, et al. (1996). Cardiopulmonary bypass in pregnancy.

Potter DD, Sundt TM 3rd, Zehr KJ, et al. (2005). Operative risk of reoperative aortic valve

Raanani E, Yau TM, David TE, Dellgren G, Sonnenberg BD & Omran A. (2000) Risk factors

Rahimtoola SH. (2003). Choice of prosthetic heart valve in adults. *J Am Coll Cardiol* 41:893-

Rahimtoola SH. (2010). Choice of prosthetic heart valve in adults. An Update. *J Am Coll* 

Rao V, Jamieson WR, Ivanov J, Armstrong S & David TE. (2000). Prosthesis-patient

Reimold SC & Rutherford JD. (2003). Valvular heart disease in pregnancy. *N Engl J Med*

Rode´s-Cabau J, Webb JG, Cheung A, et al. (2010). Transcatheter aortic valve implantation

Roedler S, Czerny M, Neuhauser J, et al. (2008). Mechanical aortic valve prostheses in the

Ross DN. (1967). Replacement of aortic and mitral valves with a pulmonary autograft.

Roudaut R, Lafitte S, Roudaut MF, et al. (2003). Fibrinolysis of mechanical prosthetic valve thrombosis: a single-center study of 127 cases. *J Am Coll Cardiol* 41: 653–658. Sadler L, McCowan L, White H, et al. (2000). Pregnancy outcomes and cardiac complications

Salam AM & Al-Mousa EN. (2004). The therapeutic potential of ximelagatran to become the

Salazar E, Espinola N, Roman L & Casanova JM. (1999). Effect of pregnancy on the duration

Salazar E, Iziguirre R, Verdego J & Mutchinick O. (1996). Failure of adjusted doses of

of bovine pericardial bioprostheses. *Am Heart J* 137:714-720.

for late pulmonary homograft stenosis after the Ross procedure. *Ann Thorac Surg* 

mismatch affects survival after aortic valve replacement. *Circulation* 102(19 Suppl

for the treatment of severe symptomatic aortic stenosis in patients at very high or prohibitive surgical risk: acute and late outcomes of the multicenter Canadian

small aortic root: Top Hat versus standard CarbomMedics aortic valve. *Ann Thorac* 

in women with mechanical bioprosthetic and homografts valves. *BJOG* 107:245–

anticoagulant of choice in medicine: a review of recently completed clinical trials.

subcutaneous heparin to prevent thrombo-embolic phenomena in pregnant patients with mechanical cardiac valve prostheses. *J Am Coll Cardiol* 27:1698–1703. Sbarouni E & Oakley CM. (1994). Outcome of pregnancy in women with valve prostheses.

Ross operation. *Eur J Cardiothorac Surg* 13:678-684.

replacement. *J Thorac Cardiovasc Surg* 129:94-103.

experience. *J Am Coll Cardiol* 55:1080–1090.

*Expert Opin Pharmacother* 5:1423-1430.

*Cardiovasc Surg* 22:19–22.

*Ann Thorac Surg* 61:259-268.

70:1953-1957.

*Cardiol* 55:2413-2426.

904.

3):III5-9.

349:52–59.

*Surg* 86:64-70.

253.

Lancet 2:956-958.

*Br Heart J* 71:196-201.

in patients with prosthetic cardiac valves – a 10 year experience. *Scand J Thorac* 


**4** 

*Greece* 

**Prosthetic Aortic Valves:** 

 *2School of Medicine, University of Ioannina, 3Chemical Engineering, University of Patras,* 

*1Mechanical Engineering & Aer/tics, University of Patras,* 

**A Surgical and Bioengineering Approach** 

Dimosthenis Mavrilas1, Efstratios Apostolakis2 and Petros Koutsoukos3

The need for replacement of damaged or malfunctioning organs or tissues in the human body has led through intense and innovative research during the past century to the development of materials and devices which are compatible with living tissues. Materials' compatibility consists in their capability to be accepted by the body when implanted and in contact with other tissues and body fluids. These materials, known as biomaterials, are the fundamental tools for engineering implantable devices dedicated to function in a specific way that substitutes corresponding function of the tissues or organs replaced due to malfunction, in synergism with the surrounding biological environment. Bone fracture healing by the incorporation of plates was known as early as the beginning of the century. Implants to replace heart valves and hip joints have been reported in the early 60s (Park & Lakes, 1992). Among the problems recorded when the first implants were employed were corrosion, mechanical failure and rejection by the body. The latter remains the main problem in the development of novel biomaterials which can be used as implants. Biomaterials now play a major role in replacing or improving the function of every major body system (skeletal, circulatory, nervous, etc.). Commonly employed implants include orthopedic devices such as total knee and hip joint replacements, spinal implants, and bone fixators; cardiac implants such as artificial heart valves and pacemakers; soft tissue implants such as breast implants and injectable collagen for soft tissue augmentation; and dental

implants to replace teeth/root systems and bony tissue in the oral cavity.

When a man-made material is placed in the human body, tissue reacts to the implant in a variety of ways depending on the material type and function. The mechanism of tissue attachment depends on the tissue response to the implant surface. In general, materials can be placed into three classes that represent the tissue response they elicit: inert, bioresorbable, and bioactive. **Inert materials** such as titanium and alumina (Al2O3) are nearly chemically inert in the body and exhibit minimal chemical interaction with adjacent tissue. A fibrous tissue capsule will normally form around inert implants. Tissue attachment with inert materials can be through tissue growth into surface irregularities, by bone cement, or by press fitting into a defect. This morphological fixation is not ideal for the long-term stability of permanent implants and often becomes a problem with orthopedic and dental implant applications. **Bioresorbable materials**, such as tricalcium phosphate and polylactic-

**1. Introduction** 

