**7. Surgical approach**

#### **7.1. Conventional AVR**

Aortic valve replacement has permitted thousands of lives to be saved since it was first suc‐ cessfully carried out by Harken and Starr in 1960 [35, 36]. Since then, advances in prosthetic technology including improved hemodynamics, durability and thromboresistance, and tech‐ niques in cardiac surgery such as cardioplegia, management of the small aortic root, and re‐ placement of associated aortic aneurysm have resulted in improvements in both operative and long-term results.

The conventional approach to AVR is the following: A mid-line incision and sternotomy is made and a pericardial well created. The patient is cannulated via the aorta and a single at‐ rial venous cannula. After cross-clamping of the aorta, a transverse aortotomy is made ap‐ proximately 1 cm above the take-off of the right coronary artery, slightly above the level of the sinotubular ridge (Figure. 3).

**Figure 3.** Transverse aortotomy

The incision is extended three-quarters of the way around the aorta, leaving the posterior one-quarter of the aorta intact allowing excellent visualization of the native aortic valve and annulus. The leaflets of the aortic valve are excised to the level of the annulus and the annu‐ lus is thoroughly debrided of any calcium. Braided 2-0 sutures with pledgets are applied. Beginning at the non-coronary commissure, the annulus is encircled with interrupted mat‐ tress sutures (Figure 4) extending from the ventricular to the aortic surface.

**Figure 4.** Aortic annulus encircled with interrupted mattress sutures

Next, each half of the suture bundles are implanted in the sewing ring and the prosthesis seated. The sutures are tied first at the left coronary cusp extending to the mid-portion of the right coronary cusp. Lastly, the sutures of the non-coronary cusp are secured, seating the valve appropriately. In case of mechanical valve prosthesis leaflet motion should always be checked and the surgeon must be assured that the coronary arteries are not obstructed. The aortotomy is closed with a double layer of polypropylene suture consisting of an underlying mattress suture and a more superficial over-and-over suture.

#### *7.1.1. Conventional AVR results*

the decision to proceed with AVR or TAVI requires careful weighing of the potential for im‐

Aortic valve replacement has permitted thousands of lives to be saved since it was first suc‐ cessfully carried out by Harken and Starr in 1960 [35, 36]. Since then, advances in prosthetic technology including improved hemodynamics, durability and thromboresistance, and tech‐ niques in cardiac surgery such as cardioplegia, management of the small aortic root, and re‐ placement of associated aortic aneurysm have resulted in improvements in both operative

The conventional approach to AVR is the following: A mid-line incision and sternotomy is made and a pericardial well created. The patient is cannulated via the aorta and a single at‐ rial venous cannula. After cross-clamping of the aorta, a transverse aortotomy is made ap‐ proximately 1 cm above the take-off of the right coronary artery, slightly above the level of

The incision is extended three-quarters of the way around the aorta, leaving the posterior one-quarter of the aorta intact allowing excellent visualization of the native aortic valve and

proved symptoms and survival and the morbidity and mortality of surgery.

**7. Surgical approach**

462 Calcific Aortic Valve Disease

**7.1. Conventional AVR**

and long-term results.

the sinotubular ridge (Figure. 3).

**Figure 3.** Transverse aortotomy

Regardless of surgical approach, elected AVR is the gold standard for the treatment of se‐ vere AS. Several studies have shown acceptable short- and long-term outcomes, as well as improved quality of life in elderly patients. Although the proportion of elderly patients with multiple comorbidities is expanding, operative outcomes following AVR were still improv‐ ing in the past decade. Recent series such as Likosky et al [25], report 30-day mortality among patients who underwent isolated AVR of 3.7% for patients <80, 6.7% in the 80 to 84 age group, and 11.7% in those ages >85 (P<0.001). Among patients undergoing AVR+CABG, 6.2% of patients <80 years died within 30 days, 9.4% among those 80 to 84, and 8.5% of pa‐ tients ≥85 years (P=0.01). Also M. Di Eusanio et al [37] published a multi-centre study in‐ cluding 638 octogenarians who underwent AVR from an Italian regional cardiac surgery registry (2003-2009), They report hospital mortality of 4.5%, which favourably compares with those reported in other series (ranging from 4.3% to 13.7%). Recent surgical series [3, 38] report operative mortality rates for aortic valve replacement as low as 1%, increasing to 9% in higher-risk patients. Long-term survival after valve replacement is 80% at 3 years, with an age-corrected postoperative survival that is nearly normalized. Significant postoper‐ ative morbidity, such as thromboembolism, haemorrhagic complications from anticoagula‐ tion, prosthetic valve dysfunction, and endocarditis, are rare and occur at a rate of 2% to 3% per year [38]. These improvements in operative outcome could be related to multiple fac‐ tors, including patient selection and perioperative management.

with a marked improvement in quality of life; in fact, their level of function and quality of

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MIS approaches appear to improve the results observed in conventional surgery. The latter shows good results with acceptable morbidity and mortality rates in most cases, including in patients with aortic valve disease, however, in some subgroups of patients these out‐ comes tend to be worse. Minimally invasive surgery aims to minimise the degree of surgical intrusiveness. Currently there are several surgical approaches. A partial upper sternotomy is the most frequently used incision for a minimally invasive approach to the aortic valve and this is usually carried out via a parasternal incision over the second and third intercostal space, depending on the patient's anatomy as observed in preoperative imaging studies such as CT. The partial sternotomy is also frequently used, and there are several possible

approaches. The table below summarises the various possible techniques (Table 3).

The "J" incision is the most widely used approach among the partial sternotomy approaches

life are the same as a general population of age-matched subjects.

**7.2. Minimally Invasive Surgical (MIS) approaches**

**Partial sternotomy**

**Thoracotomy**

**Video-assisted vision** Port access [51] **Video-direct vision**

Bustamante et al., 2012 [54]

(Figure 5 & 6).

Para-sternal incision [41,42] Trans-sternal incision [41]

T mini-sternotomy [44] V-shaped incision [45] Inverted L incision [44] Reversed L incision [46] J incision [41,47] Reversed C incision Inverted T incision [48]

Upper sternotomy (Byrne et al., 2000) [38]

Right anterior thoracotomy 2º or 3º inter-costal space [49] Right anterior thoracotomy 4º or 5º inter-costal space [50]

AESOP 3000 (Computer Motion, Goleta, CA) [52] Da Vinci System (Intuitive Surgical, Sunnyvale, CA) [53]

Zeus (Computer Motion, Goleta, CA) [41]

**Table 3.** Minimally Invasive Approaches.

A number of studies have also examined outcomes of AVR conducted with concomitant CABG surgery. With few exceptions, concomitant CABG surgery does not increase a pa‐ tient's operative risk. Considering the mounting evidence for the acceptable perioperative outcomes after AVR with or without concomitant CABG in the elderly, perhaps the fact that as many as one-third of patients >80 years of age with severe aortic stenosis are still denied surgery because of their age is due at least in part to the lack of evidence for long-term out‐ comes. Likosky et al [25] published the outcome of the very elderly undergoing aortic valve surgery comprising 7584 patients, including 815 over the age of 80. They have demonstrated that aortic valve replacement with or without concomitant CABG is a safe and effective op‐ tion for elderly patients with severe aortic stenosis. Specifically, more than half of the pa‐ tients undergoing aortic valve procedures were alive 6 years after surgery. Although concomitant CABG adds a slight mortality risk in the immediate postoperative period, it does not appreciably affect long-term survival among patients older than 80 years.

Survival has been also improved in elderly patients who underwent AVR. Asimakopoulos et al [39] reviewed United Kingdom Heart Valve Registry data from 1100 patients >80 years of age who underwent AVR from January 1986 to December 1995. They reported 30-day mortality as 6.6% with actuarial survival of 89%, 79.3%, 68.7%, and 45.8% at 1, 3, 5, and 8 years, respectively. Likosky et al [25] report a 6-year survival of 54.7% in patients aged 80 to 84 following AVR and 53.3% in patients aged 80 to 84 following AVR+CABG. Yamane et al [26] published their single centre study in 2011, reporting Survival at 1, 3, 5, and 10 years in patients aged 70–79 as 91.6%, 85.1%, 77.2%, and 38.0%, respectively, as compared with 84.1%, 75.7%, 63.0%, and 21.7% in patients aged 80– 92 (P=0.002). More recently M. Di Eusa‐ nio et al [37] report a 1, 3 and 6 year survival of 91.3%, 80.6% and 67.5% respectively in octo‐ genarian patients who underwent isolated AVR.

In several studies, estimates of quality of life, as measured by NYHA functional class im‐ provement, autonomy or satisfaction after receiving surgery have shown excellent function‐ al recovery after AVR in patients >80 years (also see Elderly patient). Wu et al [40] in a recent study, determining the economic value of the additional life given to patients under‐ going AVR, concluded that AVR is cost-effective for all ages, and still worthwhile in octoge‐ narian and nonagenarian patients.

In conclusion, conventional AVR in selected octogenarians has similar outcomes to those in "younger" elderly patients, with good mid-term survival and excellent functional recovery with a marked improvement in quality of life; in fact, their level of function and quality of life are the same as a general population of age-matched subjects.

#### **7.2. Minimally Invasive Surgical (MIS) approaches**

registry (2003-2009), They report hospital mortality of 4.5%, which favourably compares with those reported in other series (ranging from 4.3% to 13.7%). Recent surgical series [3, 38] report operative mortality rates for aortic valve replacement as low as 1%, increasing to 9% in higher-risk patients. Long-term survival after valve replacement is 80% at 3 years, with an age-corrected postoperative survival that is nearly normalized. Significant postoper‐ ative morbidity, such as thromboembolism, haemorrhagic complications from anticoagula‐ tion, prosthetic valve dysfunction, and endocarditis, are rare and occur at a rate of 2% to 3% per year [38]. These improvements in operative outcome could be related to multiple fac‐

A number of studies have also examined outcomes of AVR conducted with concomitant CABG surgery. With few exceptions, concomitant CABG surgery does not increase a pa‐ tient's operative risk. Considering the mounting evidence for the acceptable perioperative outcomes after AVR with or without concomitant CABG in the elderly, perhaps the fact that as many as one-third of patients >80 years of age with severe aortic stenosis are still denied surgery because of their age is due at least in part to the lack of evidence for long-term out‐ comes. Likosky et al [25] published the outcome of the very elderly undergoing aortic valve surgery comprising 7584 patients, including 815 over the age of 80. They have demonstrated that aortic valve replacement with or without concomitant CABG is a safe and effective op‐ tion for elderly patients with severe aortic stenosis. Specifically, more than half of the pa‐ tients undergoing aortic valve procedures were alive 6 years after surgery. Although concomitant CABG adds a slight mortality risk in the immediate postoperative period, it

does not appreciably affect long-term survival among patients older than 80 years.

Survival has been also improved in elderly patients who underwent AVR. Asimakopoulos et al [39] reviewed United Kingdom Heart Valve Registry data from 1100 patients >80 years of age who underwent AVR from January 1986 to December 1995. They reported 30-day mortality as 6.6% with actuarial survival of 89%, 79.3%, 68.7%, and 45.8% at 1, 3, 5, and 8 years, respectively. Likosky et al [25] report a 6-year survival of 54.7% in patients aged 80 to 84 following AVR and 53.3% in patients aged 80 to 84 following AVR+CABG. Yamane et al [26] published their single centre study in 2011, reporting Survival at 1, 3, 5, and 10 years in patients aged 70–79 as 91.6%, 85.1%, 77.2%, and 38.0%, respectively, as compared with 84.1%, 75.7%, 63.0%, and 21.7% in patients aged 80– 92 (P=0.002). More recently M. Di Eusa‐ nio et al [37] report a 1, 3 and 6 year survival of 91.3%, 80.6% and 67.5% respectively in octo‐

In several studies, estimates of quality of life, as measured by NYHA functional class im‐ provement, autonomy or satisfaction after receiving surgery have shown excellent function‐ al recovery after AVR in patients >80 years (also see Elderly patient). Wu et al [40] in a recent study, determining the economic value of the additional life given to patients under‐ going AVR, concluded that AVR is cost-effective for all ages, and still worthwhile in octoge‐

In conclusion, conventional AVR in selected octogenarians has similar outcomes to those in "younger" elderly patients, with good mid-term survival and excellent functional recovery

tors, including patient selection and perioperative management.

464 Calcific Aortic Valve Disease

genarian patients who underwent isolated AVR.

narian and nonagenarian patients.

MIS approaches appear to improve the results observed in conventional surgery. The latter shows good results with acceptable morbidity and mortality rates in most cases, including in patients with aortic valve disease, however, in some subgroups of patients these out‐ comes tend to be worse. Minimally invasive surgery aims to minimise the degree of surgical intrusiveness. Currently there are several surgical approaches. A partial upper sternotomy is the most frequently used incision for a minimally invasive approach to the aortic valve and this is usually carried out via a parasternal incision over the second and third intercostal space, depending on the patient's anatomy as observed in preoperative imaging studies such as CT. The partial sternotomy is also frequently used, and there are several possible approaches. The table below summarises the various possible techniques (Table 3).


**Table 3.** Minimally Invasive Approaches.

The "J" incision is the most widely used approach among the partial sternotomy approaches (Figure 5 & 6).

However there are other approaches that are gaining popularity and some groups are begin‐ ning to use it quite often, so is the case of the right anterior thoracotomy through 2º or 3º

New Therapeutic Approaches to Conventional Surgery for Aortic Stenosis in High-Risk Patients

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467

Some controversy exists as to the benefits of these approaches. There are currently very few randomized studies able to answer this question and those that do exist have certain limita‐ tions [55, 56]. However, in the medical literature we do find numerous articles that report broad series of patients in which the effects can be observed and several aspects of these ap‐

A series of advantages traditionally exist in the application of MIS for aortic valve replace‐ ment. There is no methodological uniformity across the studies that have been carried out, which sometimes complicates comparison between studies and makes it difficult to draw conclusions about the impact of these approaches on patient treatment. This is due to the fact that the aspects considered by the different studies differ in some cases. For example, some focus on length of hospitalization and specific complications and others give more relevance to surgical aspects such time spent with extracorporeal circulation or clamping. In summary, we can say that there is a group of patients about which there is a certain consen‐ sus as to the benefits of the MIS approaches. This group includes the elderly [50], and pa‐ tients who have previously undergone interventions involving myocardial revascularisation [43]. In the first case the benefit fundamentally lies in the reduction of surgical aggression in

inter-costal space (Figure 7).

**Figure 7.** Right anterior thoracotomy through 2º or 3º inter-costal space.

proaches can be compared to conventional approaches.

**Figure 5.** A & B: Reversed L incision.

**Figure 6.** Operative field distribution from surgeon view.

However there are other approaches that are gaining popularity and some groups are begin‐ ning to use it quite often, so is the case of the right anterior thoracotomy through 2º or 3º inter-costal space (Figure 7).

**Figure 7.** Right anterior thoracotomy through 2º or 3º inter-costal space.

**Figure 5.** A & B: Reversed L incision.

466 Calcific Aortic Valve Disease

**Figure 6.** Operative field distribution from surgeon view.

Some controversy exists as to the benefits of these approaches. There are currently very few randomized studies able to answer this question and those that do exist have certain limita‐ tions [55, 56]. However, in the medical literature we do find numerous articles that report broad series of patients in which the effects can be observed and several aspects of these ap‐ proaches can be compared to conventional approaches.

A series of advantages traditionally exist in the application of MIS for aortic valve replace‐ ment. There is no methodological uniformity across the studies that have been carried out, which sometimes complicates comparison between studies and makes it difficult to draw conclusions about the impact of these approaches on patient treatment. This is due to the fact that the aspects considered by the different studies differ in some cases. For example, some focus on length of hospitalization and specific complications and others give more relevance to surgical aspects such time spent with extracorporeal circulation or clamping. In summary, we can say that there is a group of patients about which there is a certain consen‐ sus as to the benefits of the MIS approaches. This group includes the elderly [50], and pa‐ tients who have previously undergone interventions involving myocardial revascularisation [43]. In the first case the benefit fundamentally lies in the reduction of surgical aggression in cases where patients are more susceptible to developing post-operative complications, lead‐ ing to a much faster functional recovery time compared to patients subjected to convention‐ al interventions. In the second case the benefit lies in the fact that it is not necessary to dissect the mediastinal structures, thus avoiding the risk of damaging coronary implants, and the complications that would entail [57, 58].

intensive care units. This has been taken into consideration in reducing the cost of the proc‐ ess, in a context of increased life expectancy and rising healthcare costs. In terms of patient treatment it is relevant in that the reduction of both is accompanied by a lesser incidence of other complications, basically infections, particularly respiratory infections, surgical wound

New Therapeutic Approaches to Conventional Surgery for Aortic Stenosis in High-Risk Patients

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469

Transcatheter aortic valve implantation (TAVI) was developed as an alternative to AVR in the very or extremely high-risk patient population. The first implant in man was performed by Cribier [68] in 2002, using a balloon expandable frame and equine valve. Since the intro‐ duction of minimally invasive and catheter-based therapies, patients want less invasive op‐ tions for all types of medical procedures including general surgical, orthopaedic, spinal, and urological operations with the goal of decreasing morbidity and mortality and shortening recovery time. Other issues with traditional aortic and mitral valve surgery include the fact that patients may not even be offered operation; in multiple series from different centres and in different countries, up to 40% of patients with severe aortic stenosis are treated medically [69, 70]. Some of these patients may be deemed to be too sick for surgery because of associat‐ ed medical comorbidities, and some may be considered too old. Finally, some who may ben‐ efit the most from an operation may decline surgery even though they develop irreversible damage from the valve lesion that could have been treated. These factors have led to the continuous development of less invasive strategies with lower mortality, lower morbidity, and less invasiveness [71]. Transcatheter aortic valve replacement seems to offer a new win‐ dow of treatment for those patients with severe aortic valve stenosis that are either extreme‐ ly high-risk or inoperable for conventional aortic valve replacement. Today around 40000 patients have received a transcatheter aortic valve implantation (TAVI) worldwide. Multiple single- and multi-centre registries, and a single randomized trial, the PARTNER trial (Place‐ ment of AoRTic TraNscathetER Valve Trial), have documented favourable outcomes using a wide spectrum of endpoints, including survival, symptom status, quality of life, and need

TAVI is currently carried out using two main approaches (retrograde transfemoral and ante‐ grade transapical), which share the same main principles. Trans-axillary artery or transaortic are other approaches that are gaining popularity when the transfemoral approach is not fea‐ sible. Specific anatomic issues must be considered in device design. These include the rigid structure and pattern of the valvular calcification and the aortic annulus, and the need for as full an apposition as possible to the annulus in an attempt to minimize periprosthetic leaks. In the case of eccentric, bulky calcifications, this may be difficult. The close proximity to the coronary ostia, the width and height of the sinuses, the membranous ventricular septum with the His bundle and the anterior leaflet of the mitral valve are also important anatomical considerations. In addition, the size and degree of severity of peripheral arterial disease are all factors that could limit catheter size [15]. It is therefore highly recommended to perform

infections and urinary tract infections.

for repeat hospitalization.

*7.3.1. Implantation techniques*

**7.3. Transcatheter Aortic Valve Replacement (TAVR)**

#### *7.2.1. Advantages and disadvantages of MIS approaches in aortic stenosis*

In other patients there are arguments in favour of MIS. Benefits have been observed in cer‐ tain aspects such as:


A certain consensus exists around the benefits mentioned above. There is also the question of the impact of MIS on duration of surgery. There is disparity in the results found in the literature. Along with other research groups, we observed that, once the learning curve has been overcome, these times tend to equal out and there is no significant difference to be ob‐ served between the different approaches. Studies that support an increase in the time for cardiopulmonary bypass and aortic clamping are Farhat et al, Detter et al, de Vaumas et al, and Stamou et al. [44, 46, 48, 67]; contradictory results can be found in Corbi et al., Sharony et al or the randomised study by Bonachi et al. [45, 50, 55]. Another aspect that is highly val‐ ued in MIS surgery is the impact it has on the duration of hospitalisation and time spent in intensive care units. This has been taken into consideration in reducing the cost of the proc‐ ess, in a context of increased life expectancy and rising healthcare costs. In terms of patient treatment it is relevant in that the reduction of both is accompanied by a lesser incidence of other complications, basically infections, particularly respiratory infections, surgical wound infections and urinary tract infections.

#### **7.3. Transcatheter Aortic Valve Replacement (TAVR)**

cases where patients are more susceptible to developing post-operative complications, lead‐ ing to a much faster functional recovery time compared to patients subjected to convention‐ al interventions. In the second case the benefit lies in the fact that it is not necessary to dissect the mediastinal structures, thus avoiding the risk of damaging coronary implants,

In other patients there are arguments in favour of MIS. Benefits have been observed in cer‐

**•** Reduction in bleeding in surgery and therefore in the use of hemoderivatives. There are also discrepancies in this aspect, as while some studies indicate the benefit [55, 59-61], others, such as Stamou et al [44] do not observe this effect. A possible explanation for this disparity of results is that in the assessment of reduced post-operative bleeding, no prior adjustments for risk factors for post-operative bleeding were made. The debate is further complicated by the fact that Dogan et al [32], observed differences in the reduction of post-surgical bleeding in a randomised study. In our group we did observe a statistically significant reduction in blood loss during surgery and in the need for hemoderivatives.

**•** Reduction in the pain perceived by the patient. Numerous studies indicate this benefit [55, 62, 63] which is based on a reduction in the distension of costovertebral ligaments and traction of the brachial plexus. This results in reduced consumption of analgesic pharma‐

**•** Less reduction in tidal lung volume, thus reducing the appearance of respiratory compli‐

**•** Better aesthetic results. This is one of the clear benefits of the technique, due to the re‐

**•** There are other benefits, such as the reduction in complications in the surgical wound/ in‐ fections. Grossi et al [64] observe an incidence of infection of 0.9% for minimally invasive approaches as against 5.7% in cases of patients with the approach by sternotomy, p=0.05. It has been observed that this difference increases in elderly patients (1.8 and 7.7% respec‐ tively). Other authors observe that in comparison with the classical approach there is a

A certain consensus exists around the benefits mentioned above. There is also the question of the impact of MIS on duration of surgery. There is disparity in the results found in the literature. Along with other research groups, we observed that, once the learning curve has been overcome, these times tend to equal out and there is no significant difference to be ob‐ served between the different approaches. Studies that support an increase in the time for cardiopulmonary bypass and aortic clamping are Farhat et al, Detter et al, de Vaumas et al, and Stamou et al. [44, 46, 48, 67]; contradictory results can be found in Corbi et al., Sharony et al or the randomised study by Bonachi et al. [45, 50, 55]. Another aspect that is highly val‐ ued in MIS surgery is the impact it has on the duration of hospitalisation and time spent in

cations such as atelectasis by maintaining the integrity of the thorax [56].

duced size of the surgical incisions and their relocation to less visible areas.

lesser incidence of infectious complications [65, 66].

and the complications that would entail [57, 58].

tain aspects such as:

468 Calcific Aortic Valve Disease

ceuticals by the patient.

*7.2.1. Advantages and disadvantages of MIS approaches in aortic stenosis*

Transcatheter aortic valve implantation (TAVI) was developed as an alternative to AVR in the very or extremely high-risk patient population. The first implant in man was performed by Cribier [68] in 2002, using a balloon expandable frame and equine valve. Since the intro‐ duction of minimally invasive and catheter-based therapies, patients want less invasive op‐ tions for all types of medical procedures including general surgical, orthopaedic, spinal, and urological operations with the goal of decreasing morbidity and mortality and shortening recovery time. Other issues with traditional aortic and mitral valve surgery include the fact that patients may not even be offered operation; in multiple series from different centres and in different countries, up to 40% of patients with severe aortic stenosis are treated medically [69, 70]. Some of these patients may be deemed to be too sick for surgery because of associat‐ ed medical comorbidities, and some may be considered too old. Finally, some who may ben‐ efit the most from an operation may decline surgery even though they develop irreversible damage from the valve lesion that could have been treated. These factors have led to the continuous development of less invasive strategies with lower mortality, lower morbidity, and less invasiveness [71]. Transcatheter aortic valve replacement seems to offer a new win‐ dow of treatment for those patients with severe aortic valve stenosis that are either extreme‐ ly high-risk or inoperable for conventional aortic valve replacement. Today around 40000 patients have received a transcatheter aortic valve implantation (TAVI) worldwide. Multiple single- and multi-centre registries, and a single randomized trial, the PARTNER trial (Place‐ ment of AoRTic TraNscathetER Valve Trial), have documented favourable outcomes using a wide spectrum of endpoints, including survival, symptom status, quality of life, and need for repeat hospitalization.

#### *7.3.1. Implantation techniques*

TAVI is currently carried out using two main approaches (retrograde transfemoral and ante‐ grade transapical), which share the same main principles. Trans-axillary artery or transaortic are other approaches that are gaining popularity when the transfemoral approach is not fea‐ sible. Specific anatomic issues must be considered in device design. These include the rigid structure and pattern of the valvular calcification and the aortic annulus, and the need for as full an apposition as possible to the annulus in an attempt to minimize periprosthetic leaks. In the case of eccentric, bulky calcifications, this may be difficult. The close proximity to the coronary ostia, the width and height of the sinuses, the membranous ventricular septum with the His bundle and the anterior leaflet of the mitral valve are also important anatomical considerations. In addition, the size and degree of severity of peripheral arterial disease are all factors that could limit catheter size [15]. It is therefore highly recommended to perform an adequate preoperative assessment of the degree of peripheral arterial disease through imaging studies such as CT (Figure 8).

**Figure 8.** (A) CT reconstruction of the aorta. (B) CT reconstruction of iliofemoral arteries

Most teams perform the procedure under general anaesthesia, although sedation and an‐ algesia may suffice for the transfemoral approach. Peri-procedural transoesophageal echocardiography (TEE) monitoring is desirable to correctly position the valve as well as to detect complications. After crossing the aortic valve, Balloon aortic valvuloplasty is performed to pre-dilate the native valve and serve as a rehearsal for TAVI. Simultaneous rapid pacing decreases cardiac output, stabilizing the balloon during inflation. Normal blood pressure must be completely recovered between sequences of rapid pacing. In or‐ der to position the prosthesis at the level of the aortic valve annulus different methods can be used, such as fluoroscopy to assess the level of valve calcification (Figure 9); aor‐ tography, using different views, performed at the beginning of the procedure and repeat‐ ed with the undeployed prosthesis in place, to determine the position of the valve and the plane of alignment of the aortic cusps; and echocardiography. TEE is particularly helpful in cases with moderate calcification.

**Figure 9.** First row (A). Edwards Sapiens transfemoral implantation. Second row (B). Transfemoral Corevalve implanta‐

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The specific issues related to the different approaches include the following: In the transfe‐ moral approach, close attention should be paid to the vascular access. The common femoral artery can be either prepared surgically or approached percutaneously. Echo-guided femo‐ ral access could be useful. Manipulation of the introductory sheaths should be careful and fluoroscopically guided. Depending on the size of the device, closure of the vascular access can be effected surgically or using a percutaneous closure device. Femoral access and cardi‐ opulmonary bypass should be on standby for patients for whom surgical conversion is an

The transapical approach requires an antero-lateral mini-thoracotomy (Figure 10), pericar‐ diotomy, identification of the apex, and then puncture of the left ventricle using a needle through purse-string sutures. Subsequently, an introductory sheath is positioned in the LV,

tion. Third row (C). Edwards Sapiens transapical implantation.

and the prosthesis is implanted using the antegrade route.

option in case of complications.

Three dimensional real-time TEE seems to provide extra information to the teams that use it. When positioning is considered correct, the prosthesis is released. Rapid pacing is used at this stage for balloon-expandable devices but not for self-expanding ones. Immediately after TAVI, aortography and, whenever available, TEE or, in the absence of TEE, Transthoracic echocardiogram(TTE) are performed to assess the location and degree of aortic regurgitation and the patency of the coronary arteries, and to rule out complications such as haemoperi‐ cardium, and aortic dissection. The hemodynamic results are assessed using pressure re‐ cordings and/or echocardiography. After the procedure, the patients should stay in intensive care for at least 24 hours and be closely monitored for several days, particularly as regards hemodynamics, vascular access, rhythm disturbances (especially late atrioventricu‐ lar block), and renal function.

an adequate preoperative assessment of the degree of peripheral arterial disease through

Most teams perform the procedure under general anaesthesia, although sedation and an‐ algesia may suffice for the transfemoral approach. Peri-procedural transoesophageal echocardiography (TEE) monitoring is desirable to correctly position the valve as well as to detect complications. After crossing the aortic valve, Balloon aortic valvuloplasty is performed to pre-dilate the native valve and serve as a rehearsal for TAVI. Simultaneous rapid pacing decreases cardiac output, stabilizing the balloon during inflation. Normal blood pressure must be completely recovered between sequences of rapid pacing. In or‐ der to position the prosthesis at the level of the aortic valve annulus different methods can be used, such as fluoroscopy to assess the level of valve calcification (Figure 9); aor‐ tography, using different views, performed at the beginning of the procedure and repeat‐ ed with the undeployed prosthesis in place, to determine the position of the valve and the plane of alignment of the aortic cusps; and echocardiography. TEE is particularly

Three dimensional real-time TEE seems to provide extra information to the teams that use it. When positioning is considered correct, the prosthesis is released. Rapid pacing is used at this stage for balloon-expandable devices but not for self-expanding ones. Immediately after TAVI, aortography and, whenever available, TEE or, in the absence of TEE, Transthoracic echocardiogram(TTE) are performed to assess the location and degree of aortic regurgitation and the patency of the coronary arteries, and to rule out complications such as haemoperi‐ cardium, and aortic dissection. The hemodynamic results are assessed using pressure re‐ cordings and/or echocardiography. After the procedure, the patients should stay in intensive care for at least 24 hours and be closely monitored for several days, particularly as regards hemodynamics, vascular access, rhythm disturbances (especially late atrioventricu‐

**Figure 8.** (A) CT reconstruction of the aorta. (B) CT reconstruction of iliofemoral arteries

helpful in cases with moderate calcification.

lar block), and renal function.

imaging studies such as CT (Figure 8).

470 Calcific Aortic Valve Disease

**Figure 9.** First row (A). Edwards Sapiens transfemoral implantation. Second row (B). Transfemoral Corevalve implanta‐ tion. Third row (C). Edwards Sapiens transapical implantation.

The specific issues related to the different approaches include the following: In the transfe‐ moral approach, close attention should be paid to the vascular access. The common femoral artery can be either prepared surgically or approached percutaneously. Echo-guided femo‐ ral access could be useful. Manipulation of the introductory sheaths should be careful and fluoroscopically guided. Depending on the size of the device, closure of the vascular access can be effected surgically or using a percutaneous closure device. Femoral access and cardi‐ opulmonary bypass should be on standby for patients for whom surgical conversion is an option in case of complications.

The transapical approach requires an antero-lateral mini-thoracotomy (Figure 10), pericar‐ diotomy, identification of the apex, and then puncture of the left ventricle using a needle through purse-string sutures. Subsequently, an introductory sheath is positioned in the LV, and the prosthesis is implanted using the antegrade route.

higher incidence of major strokes (5.0% versus 1.1%) as well as increased major vascular complications (16.2% versus 1.1%) with TAVR, both of which may adversely impact early and longer-term outcome. Longer-term outcomes will be required. These results were re‐ ceived enthusiastically; however, they have important limitations. Firstly, they can be ap‐ plied only in patients similar to those in the study (i.e., those patients deemed to be inoperable). Secondly, they are the result of treatment by very experienced operators work‐ ing as a heart team in a hybrid operating room or similar facility with a specific device and

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The results of the PARTNER Cohort A trial also have important implications. The pri‐ mary endpoint of the trial was met, with TAVR found not to be inferior to aortic valve replacement for all-cause mortality at 1 year (TAVR versus aortic valve replacement, 24.2% versus 26.8%, respectively, p₌0.001 for non-inferiority). Death at 30 days was lower than expected in both arms of the trial: TAVR mortality (3.4%) was the lowest reported in any series, despite an early generation device and limited previous operator experi‐ ence. Aortic valve replacement mortality (6.5%) was lower than the expected operative mortality (11.8%). Furthermore, both TAVR and aortic valve replacement were associated with important but different peri-procedural hazards: major strokes at 30 days (3.8% ver‐ sus 2.1%, p=0.20) and 1 year (5.1% versus 2.4%, p=0.07), and major vascular complica‐ tions were more frequent with TAVR (11.0% versus 3.2%, p<0.001). Major bleeding (9.3% versus 19.5%, p<0.001) and new onset atrial fibrillation (8.6% versus 16.0%, p<0.001) were

Rates of stroke were similar whether the access was transfemoral or transapical. Biopros‐ thetic-valve gradients and orifice areas were slightly better after transcatheter replacement than after surgical replacement, probably because of the less bulky support frame with transcatheter replacement [34]. However, transcatheter replacement resulted in much more frequent paravalvular aortic regurgitation. Although this condition was stable at 1 year, re‐ peat intervention was required in some cases. A reduction in the incidence and severity of paravalvular AR represents an obvious target for technical improvements in the design of transcatheter valves and of implantation techniques [24]. Clinical benefits of transcatheter replacement included significantly shorter stays in the intensive care unit and in hospital. In addition, the NYHA functional class and 6-minute walk distance were strikingly improved at 1 year [34]. Transcatheter aortic valve implantation by means of either the transfemoral or the transapical approach is a reasonable and promising treatment option for patients who are at high risk or had been refused for conventional AVR. Recommendations made to indi‐ vidual patients must balance the appeal of avoiding the known risks of open-heart surgery against the less invasive transcatheter approach, which has different and less well under‐

stood risks, particularly with respect to stroke and paravalvular aortic regurgitation.

These prostheses were designed by industry with a view to facilitating the implantation of the prosthesis through conventional surgery; that is to say, using a cardio-pulmonary by‐

**8. New prostheses in mini-invasive approaches**

do not necessarily apply to other devices.

more frequent with aortic valve replacement.

**Figure 10.** Anterior minitoracotomy for transapical approach of a TAVI procedure.

#### *7.3.2. TAVR results*

The PARTNER trial has been followed with great interest. The PARTNER trial was basically 2 parallel trials: 1) PARTNER Cohort A, which randomized high-risk surgical patients to ei‐ ther traditional aortic valve replacement or to TAVI by either a transfemoral or transapical approach; and 2) PARTNER Cohort B in which patients who were inoperable were random‐ ized to either a TAVR by a transfemoral approach or to conventional medical therapy, which typically consisted of balloon aortic valvuloplasty.

Screening required evaluation by 2 experienced cardiac surgeons to agree on the surgical risk using the STS Predicted Risk of Mortality score and was rigorous, with approximately one-quarter to one-third of screened patients subsequently enrolled. The primary endpoint was death from any cause at 1 year. The results of PARTNER Cohort B included 358 patients deemed unsuitable for conventional aortic valve replacement because of predicted probabil‐ ity of≥ 50% mortality or the risk of a serious irreversible complication within 30 days. At 1 year, all-cause mortality with TAVR was 30.7% versus 50.7% with medical therapy (hazard ratio: 0.55, 95% confidence interval: 0.40 to 0.74). Despite the marked improvement in sur‐ vival and event-free survival, there were some significant safety hazards, particularly a higher incidence of major strokes (5.0% versus 1.1%) as well as increased major vascular complications (16.2% versus 1.1%) with TAVR, both of which may adversely impact early and longer-term outcome. Longer-term outcomes will be required. These results were re‐ ceived enthusiastically; however, they have important limitations. Firstly, they can be ap‐ plied only in patients similar to those in the study (i.e., those patients deemed to be inoperable). Secondly, they are the result of treatment by very experienced operators work‐ ing as a heart team in a hybrid operating room or similar facility with a specific device and do not necessarily apply to other devices.

The results of the PARTNER Cohort A trial also have important implications. The pri‐ mary endpoint of the trial was met, with TAVR found not to be inferior to aortic valve replacement for all-cause mortality at 1 year (TAVR versus aortic valve replacement, 24.2% versus 26.8%, respectively, p₌0.001 for non-inferiority). Death at 30 days was lower than expected in both arms of the trial: TAVR mortality (3.4%) was the lowest reported in any series, despite an early generation device and limited previous operator experi‐ ence. Aortic valve replacement mortality (6.5%) was lower than the expected operative mortality (11.8%). Furthermore, both TAVR and aortic valve replacement were associated with important but different peri-procedural hazards: major strokes at 30 days (3.8% ver‐ sus 2.1%, p=0.20) and 1 year (5.1% versus 2.4%, p=0.07), and major vascular complica‐ tions were more frequent with TAVR (11.0% versus 3.2%, p<0.001). Major bleeding (9.3% versus 19.5%, p<0.001) and new onset atrial fibrillation (8.6% versus 16.0%, p<0.001) were more frequent with aortic valve replacement.

Rates of stroke were similar whether the access was transfemoral or transapical. Biopros‐ thetic-valve gradients and orifice areas were slightly better after transcatheter replacement than after surgical replacement, probably because of the less bulky support frame with transcatheter replacement [34]. However, transcatheter replacement resulted in much more frequent paravalvular aortic regurgitation. Although this condition was stable at 1 year, re‐ peat intervention was required in some cases. A reduction in the incidence and severity of paravalvular AR represents an obvious target for technical improvements in the design of transcatheter valves and of implantation techniques [24]. Clinical benefits of transcatheter replacement included significantly shorter stays in the intensive care unit and in hospital. In addition, the NYHA functional class and 6-minute walk distance were strikingly improved at 1 year [34]. Transcatheter aortic valve implantation by means of either the transfemoral or the transapical approach is a reasonable and promising treatment option for patients who are at high risk or had been refused for conventional AVR. Recommendations made to indi‐ vidual patients must balance the appeal of avoiding the known risks of open-heart surgery against the less invasive transcatheter approach, which has different and less well under‐ stood risks, particularly with respect to stroke and paravalvular aortic regurgitation.

### **8. New prostheses in mini-invasive approaches**

**Figure 10.** Anterior minitoracotomy for transapical approach of a TAVI procedure.

which typically consisted of balloon aortic valvuloplasty.

The PARTNER trial has been followed with great interest. The PARTNER trial was basically 2 parallel trials: 1) PARTNER Cohort A, which randomized high-risk surgical patients to ei‐ ther traditional aortic valve replacement or to TAVI by either a transfemoral or transapical approach; and 2) PARTNER Cohort B in which patients who were inoperable were random‐ ized to either a TAVR by a transfemoral approach or to conventional medical therapy,

Screening required evaluation by 2 experienced cardiac surgeons to agree on the surgical risk using the STS Predicted Risk of Mortality score and was rigorous, with approximately one-quarter to one-third of screened patients subsequently enrolled. The primary endpoint was death from any cause at 1 year. The results of PARTNER Cohort B included 358 patients deemed unsuitable for conventional aortic valve replacement because of predicted probabil‐ ity of≥ 50% mortality or the risk of a serious irreversible complication within 30 days. At 1 year, all-cause mortality with TAVR was 30.7% versus 50.7% with medical therapy (hazard ratio: 0.55, 95% confidence interval: 0.40 to 0.74). Despite the marked improvement in sur‐ vival and event-free survival, there were some significant safety hazards, particularly a

*7.3.2. TAVR results*

472 Calcific Aortic Valve Disease

These prostheses were designed by industry with a view to facilitating the implantation of the prosthesis through conventional surgery; that is to say, using a cardio-pulmonary by‐ pass and aortic clamping. The gold standard for the use of these prostheses is in association with MIS approaches, providing a reduction in surgical aggression in addition to the reduc‐ tion in ECC and aortic clamping time, the consequences of which we have already exam‐ ined. These designs have the common feature of being expandable, anchoring themselves to the aortic ring in a similar way to the devices used in TAVI.

To date there are three commercially available models: 3f Enable ® (Medtronic Inc, Minne‐ apolis, MN), Perceval S (Sorin Group Cardio Srl, Sallugia, Italy) and Intuity (Edwards Life‐ sciences, Irvine, California). These differ from each other in a few characteristics.

**3f Enable ® aortic bioprosthesis** (Figure 11): This prosthesis is especially indicated in pa‐ tients with small aortic annulus where the possibility of having a severe mismatch is high with the use of conventional prosthesis. Several studies report an acceptable hemodynamic behavior with this type of prosthesis. Furthermore, there is no need to match the measure between the annulus and the sinotubular junction, because the prosthesis is anchored only to the annulus. Of the three prostheses this is the oldest and different models have been de‐ veloped since its initial commercialisation with a view to improving hemodynamics, dura‐ bility and facilitating surgeons in its implantation [72-74]

**Figure 12.** Perceval S (Sorin Biomedica Cardio Srl, Sallugia, Italy)

does not require stitches in the aortic ring.

**Figure 13.** Intuity (Edwards Lifesciences, Irvine, California)

**Intuity (Edwards Lifesciences, Irvine, California)** (Figure 13): Of these three prostheses this is the most recently commercialised and results as to its hemodynamic profile and durability in clinical practice are not available. Arguments in its favour, as put forward by the compa‐ ny, are the conjunction between the Edwards Perimount bioprosthesis, the clinical and he‐ modynamic results of which are widely known, and the experience in the development of new prostheses such as the Sapien transcatheter. The mode of implantation for this prosthe‐ sis allows the aortic clamping and extracorporeal circulation times to be reduced. For a number of reasons, one of the most important being ischemic reperfusion, these two varia‐ bles are known to be directly related to the surgical morbidity and mortality of procedures, which is why this model may be attractive, in addition to the comfort of implantation, as it

New Therapeutic Approaches to Conventional Surgery for Aortic Stenosis in High-Risk Patients

http://dx.doi.org/10.5772/54333

475

The disadvantage of these prostheses is their cost, as they ultimately increase resource con‐ sumption. Results for hemodynamics and durability are becoming better understood as pre‐ liminary studies are published. From the beginning we find data in the literature relating to safety and effectiveness in the implantation of aortic valve replacements. Some of the com‐ plications associated with their use, such as perivalvular leaks are understood to be inti‐ mately related to the decalcification of the ring; in some cases, it has been possible to correct

**Figure 11.** Enable ® (Medtronic Inc, Minneapolis, MN)

**Perceval S (Sorin Biomedica Cardio Srl, Sallugia, Italy)** (Figure 12): Prosthesis aimed at pa‐ tients with a high surgical risk in which a reduction in surgery time may have a significant impact, for patients where it is necessary to carry out mixed procedures, and patients under‐ going re-intervention, and patients with a small aortic ring, because of the hemodynamic characteristics of the prosthesis [75, 76]

**Figure 12.** Perceval S (Sorin Biomedica Cardio Srl, Sallugia, Italy)

pass and aortic clamping. The gold standard for the use of these prostheses is in association with MIS approaches, providing a reduction in surgical aggression in addition to the reduc‐ tion in ECC and aortic clamping time, the consequences of which we have already exam‐ ined. These designs have the common feature of being expandable, anchoring themselves to

To date there are three commercially available models: 3f Enable ® (Medtronic Inc, Minne‐ apolis, MN), Perceval S (Sorin Group Cardio Srl, Sallugia, Italy) and Intuity (Edwards Life‐

**3f Enable ® aortic bioprosthesis** (Figure 11): This prosthesis is especially indicated in pa‐ tients with small aortic annulus where the possibility of having a severe mismatch is high with the use of conventional prosthesis. Several studies report an acceptable hemodynamic behavior with this type of prosthesis. Furthermore, there is no need to match the measure between the annulus and the sinotubular junction, because the prosthesis is anchored only to the annulus. Of the three prostheses this is the oldest and different models have been de‐ veloped since its initial commercialisation with a view to improving hemodynamics, dura‐

**Perceval S (Sorin Biomedica Cardio Srl, Sallugia, Italy)** (Figure 12): Prosthesis aimed at pa‐ tients with a high surgical risk in which a reduction in surgery time may have a significant impact, for patients where it is necessary to carry out mixed procedures, and patients under‐ going re-intervention, and patients with a small aortic ring, because of the hemodynamic

sciences, Irvine, California). These differ from each other in a few characteristics.

the aortic ring in a similar way to the devices used in TAVI.

474 Calcific Aortic Valve Disease

bility and facilitating surgeons in its implantation [72-74]

**Figure 11.** Enable ® (Medtronic Inc, Minneapolis, MN)

characteristics of the prosthesis [75, 76]

**Intuity (Edwards Lifesciences, Irvine, California)** (Figure 13): Of these three prostheses this is the most recently commercialised and results as to its hemodynamic profile and durability in clinical practice are not available. Arguments in its favour, as put forward by the compa‐ ny, are the conjunction between the Edwards Perimount bioprosthesis, the clinical and he‐ modynamic results of which are widely known, and the experience in the development of new prostheses such as the Sapien transcatheter. The mode of implantation for this prosthe‐ sis allows the aortic clamping and extracorporeal circulation times to be reduced. For a number of reasons, one of the most important being ischemic reperfusion, these two varia‐ bles are known to be directly related to the surgical morbidity and mortality of procedures, which is why this model may be attractive, in addition to the comfort of implantation, as it does not require stitches in the aortic ring.

**Figure 13.** Intuity (Edwards Lifesciences, Irvine, California)

The disadvantage of these prostheses is their cost, as they ultimately increase resource con‐ sumption. Results for hemodynamics and durability are becoming better understood as pre‐ liminary studies are published. From the beginning we find data in the literature relating to safety and effectiveness in the implantation of aortic valve replacements. Some of the com‐ plications associated with their use, such as perivalvular leaks are understood to be inti‐ mately related to the decalcification of the ring; in some cases, it has been possible to correct other complications, such as bad positioning, with new designs being applied to the already existing prosthetics [77]

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