**6. Patient selection**

Propter selection of patients for valve replacement can bring us excellent long-term results, long-term survival and low incidence of valve-related complications.

In some studies of patients followed over longer time frames, freedom from all valve-related events and freedom from reoperation were improved in patients with mechanical valve prostheses as compared to patients with biological prostheses. [9,16,25] Key of long-term success of mechanical valve prostheses is anticoagulation. Patients that are inconsistent, noncompliant or incapable of managing medications are not good candidates for long-term chronic anticoagulation.[39,41] Also patients with higher levels of education and those from geographic areas with a good medical infrastructure have better compliance with necessary medications and anticoagulant monitoring.[31]

70% at 5 years, which is similar to an age- and sex-matched population without aortic valve disease. Most patients report improved functional capacity and quality of life, with more than

Surgical Valve Replacement (Bioprosthetic VS Mechanical)

http://dx.doi.org/10.5772/53687

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A major deterrent to mechanical valve replacement in the younger patient is the impact of long-term anticoagulation. Mechanical valves are, however, more ideal for younger patients due to their excellent durability characteristics. Most importantly, younger patients (i.e., patients under the age of 50 years) are a low-risk subset for valve related events. These individuals have very few risk factors for TE, and thus anticoagulation can be run at the lower end of the therapeutic target range, decreasing the incidence of anticoagulant-related hemor‐ rhage without altering the incidence of TE. In fact, many infants and children have been managed with only aspirin with quite good long term results. While this is not recommended in patients older than infancy, it is a feasible alternative. A recent study in patients under 50 years of age followed 254 patients for up to 20 years and found an exceedingly low rate of valve related events, an exceptional long-term overall survival of nearly 88%, and event-free

Patients with an absolute requirement for long-term anticoagulation such as atrial fibrillation, previous thromboembolic events, hypercoagulable state, severe LVD, another mechanical heart valve in place, or intracardiac thrombus, should receive a mechanical valve regardless of age. Patients in whom anticoagulation with warfarin is contraindicated, such as women of child-bearing age wishing to become pregnant, patients with other bleeding disorders, or those who refuse anticoagulation should receive a bioprosthesis. There is growing interest in using mechanical prostheses in women of child-bearing age and providing anticoagulation with subcutaneous low-molecular weight heparin injections. Patients with end-stage renal failure were previously believed to have significantly elevated risk for early bioprosthetic structural valve deterioration. However, increased anticoagulation- related complications are also more likely in this group, and the current ACC/AHA guidelines do not recommend routine use of

The decision between bioprosthetic and mechanical valve should be made by the patient with educated input regarding the pros and cons of each option from the patient's physicians. Today surgeons implant bioprosthetic valves in younger patients who wish to avoid anticoagulation due to lifestyle concerns (e.g. young, active individual, desire to become pregnant, etc.), although surgeons generally will guide patients toward a mechanical option at the time of

Aortic valve replacement is most frequently done through a median sternotomy, meaning the incision is made by cutting through the sternum. Once the pericardium has been opened, the patient is put on a cardiopulmonary bypass machine. This machine takes over the task of breathing for the patient and pumping their blood around while the surgeon

90% of patients feeling better after surgery.3

survival probability of 92% at 19 years.[3,44,45]

mechanical prostheses in these patients.[3,7,8,9,10]

**7. Operative technique**

replaces the heart valve.

redo-AVR if their life expectancy exceeds 10–15 years at that time.[3]

Many centers used bioprosthetic valves for patients who are older than 70 year, based on data by Akins.[42] In patients younger than 60 years of age, the best solution would be implantation of mechanical valves, based on prosthesis durability and they have low-risk for valve-related events.[21] In decade between 60 and 70 years of age, other factors have to be taken into account.7 According to some studies, patients over 65 years at the time of surgery should receive a biologic valve. Patients under the age of 60 should have a mechanical prosthesis to minimize the risk of structural failure requiring repeat AVR in an octogenarian. Patients between 60 and 65 represent the group in whom there is still considerable debate regarding prosthesis selection. Those patients who have comorbidities such as severe CAD may be less likely to outlive their prosthesis and should receive a biologic valve. A detailed discussion of these risks and benefits of prosthesis selection should occur with all patients and their families prior to entering the operating room. [3,7,22,24,25,37,38]

In the early follow-up period, anticoagulation – related hemorrhage is the most common unwanted event for mechanical valve prostheses. Over the first 10 years of follow-up there is a higher incidence of valve-related events in patients with mechanical prostheses as opposed to those with biologic valves.[32] However, in the next 10 to 20 years after AVR, the incidence of valve failure and valve-related complications are much higher at biologic prostheses than those with mechanical valve prostheses. Some series showed that the time to biologic valve failure was only 7.6 years.[43] This failure rate will increase over time. However, freedom from valve-related events is more strongly influenced by pre-existing comorbidities than the presence of mechanical prostheses.[21], [22, 25, 31]

The elderly patient with severe aortic stenosis poses a therapeutic challenge. In considering elderly patients for aortic valve replacement, important factors include the presence of symptoms, physiologic age, patient expectations, anticipated future activities, and comorbid‐ ity. The operation itself carries a higher risk than in younger patients. Extensive calcification of the aorta and annulus as well as fragile tissue presents significant technical difficulties for the surgeon. In addition, particularly in women, the aortic root and annulus may be small and require concomitant enlargement to accommodate the valve prosthesis. Furthermore, pro‐ truding arch atheroma occurs in one-fifth of patients *>* 65 years of age and significantly increases the risk of stroke and mortality during cardiac surgery. Major postoperative complications, nevertheless, remain high, with the incidence of permanent stroke between 4 and 6%. Rehabilitation can also be a problem, as elderly patients take longer to recover from surgery. Survival has clearly improved in these elderly patients with severe symptomatic aortic stenosis who undergo aortic valve replacement. Survival is 80–85% at 1 year and 60– 70% at 5 years, which is similar to an age- and sex-matched population without aortic valve disease. Most patients report improved functional capacity and quality of life, with more than 90% of patients feeling better after surgery.3

A major deterrent to mechanical valve replacement in the younger patient is the impact of long-term anticoagulation. Mechanical valves are, however, more ideal for younger patients due to their excellent durability characteristics. Most importantly, younger patients (i.e., patients under the age of 50 years) are a low-risk subset for valve related events. These individuals have very few risk factors for TE, and thus anticoagulation can be run at the lower end of the therapeutic target range, decreasing the incidence of anticoagulant-related hemor‐ rhage without altering the incidence of TE. In fact, many infants and children have been managed with only aspirin with quite good long term results. While this is not recommended in patients older than infancy, it is a feasible alternative. A recent study in patients under 50 years of age followed 254 patients for up to 20 years and found an exceedingly low rate of valve related events, an exceptional long-term overall survival of nearly 88%, and event-free survival probability of 92% at 19 years.[3,44,45]

Patients with an absolute requirement for long-term anticoagulation such as atrial fibrillation, previous thromboembolic events, hypercoagulable state, severe LVD, another mechanical heart valve in place, or intracardiac thrombus, should receive a mechanical valve regardless of age. Patients in whom anticoagulation with warfarin is contraindicated, such as women of child-bearing age wishing to become pregnant, patients with other bleeding disorders, or those who refuse anticoagulation should receive a bioprosthesis. There is growing interest in using mechanical prostheses in women of child-bearing age and providing anticoagulation with subcutaneous low-molecular weight heparin injections. Patients with end-stage renal failure were previously believed to have significantly elevated risk for early bioprosthetic structural valve deterioration. However, increased anticoagulation- related complications are also more likely in this group, and the current ACC/AHA guidelines do not recommend routine use of mechanical prostheses in these patients.[3,7,8,9,10]

The decision between bioprosthetic and mechanical valve should be made by the patient with educated input regarding the pros and cons of each option from the patient's physicians. Today surgeons implant bioprosthetic valves in younger patients who wish to avoid anticoagulation due to lifestyle concerns (e.g. young, active individual, desire to become pregnant, etc.), although surgeons generally will guide patients toward a mechanical option at the time of redo-AVR if their life expectancy exceeds 10–15 years at that time.[3]
