**7. Implantation approaches**

With regard to the delivery systems and their introduction into ascending aorta, two specific pathways have been explored so far: the antegrade pathway, which uses direct transapical access, and the retrograde pathway, which uses either transfemoral or trans-subclavian or trans-axillary access [11].

#### **7.1. The transapical approach**

**Figure 7.** Profile of the CoreValve Revaving System (A) and Edwards SAPIEN Transcatheter Heart Valve (B)

490 Calcific Aortic Valve Disease

ly positioned and deployed, similar to the antegrade approach.

Newer devices that have first-in-man application include Paniagua (Endoluminal Tech‐ nology Research, Miami, FL), Enable (ATS, Minneapolis, MN), AoTx (Hansen Medical, Mountain View, CA), Perceval (Sorin Group, Arvada, CO), Jena (JenaValve Technology, Wilmington, DE), Lotus Valve (Sadra Medical, Campbell, CA), and Direct Flow percuta‐ neous aortic valve (Direct Flow Medical, Inc., Santa Rosa, CA). TAVI represents a unique challenge for anesthesiologists. As with other invasive procedures, a careful preoperative assessment, appropriate intraoperative monitoring and imaging, meticulous management of hemodynamics, and early treatment of expected side effects and complications is of ut‐ most importance. An unexpected decrease or increase in systemic vascular resistance re‐ sulting in decreased coronary perfusion pressure or acute heart failure by elevated left ventricular end-diastolic pressure should be avoided by maintaining a normotensive blood pressure and heart rate between 60 bpm and 100 bpm. The choice of anesthetic technique, either local anesthesia with mild sedation promoting spontaneous respiration, deep intravenous sedation with insertion of a laryngeal mask, or general anesthesia, var‐ ies among centers and is probably not associated with a significant difference in out‐ come. Post valvuloplasty and implantation, which were done under rapid right ventricular pacing due to reduce left ventricular ejection and cardiac motion, may require some additional inotropic support. Tracheal extubation can usually be done at the end of the procedure. Close postoperative monitoring is necessary, and admission to an inten‐ sive care unit is required. However, at present a retrograde approach through the femo‐ ral artery is used. During the procedure, a balloon valvuloplasty is first done to facilitate passage of the native aortic valve. During rapid right ventricular pacing, the prosthesis is positioned and deployed under fluoroscopy and echocardiographic guidance. Alternative‐ ly, in patients with difficult vascular access because of extensive calcifications or tortuosi‐ ty of the femoral artery or aorta, a transapical approach can be used. After a partial thoracotomy, direct puncture of the apical portion of the left ventricular free wall is done to gain catheter access to the left ventricle and aortic valve. The prosthesis is subsequent‐ The main advantages of using transapical procedures are: [1] the feasibility does not rely on the absence of a concomitant peripheral vascular disease or previous aortic surgery; [2] the delivery system seems to be more "steady" and the procedure itself more "straightforward"; and [3] this access potentially reduces the risk of calcium dislodgement due to the passage of a stiff transfemoral device into a diseased aortic arch. A transapical approach can be used in the operating room, in a hybrid room, or in a catheterization laboratory with a patient un‐ der general anesthesia. Regardless of where the transapical approach is done, it is a prereq‐ uisite that high-quality fluoroscopic imaging must be guaranteed. Apical bleeding is very rare, mostly related to patient tissue fragility or to the team learning curve, and represents the most dangerous complication related to transapical access itself. In transapical TAVI, the cardiac apex is prepared through a small left anterolateral mini-thoracotomy using a pursestring or a crossing suture reinforced by pledgets and, after the procedure, a chest tube is routinely inserted into the left pleura with pain releasers injected in the intercostal tissue (Figure 8).

#### **7.2. The transfemoral approach**

The transfemoral approach is used mostly in cardiac catheterization laboratory or a hybrid room. One of the main advantages of this technique is that it allows fully percutaneous im‐ plantation in conscious patients, as long as the peripheral vessels are of an adequate caliber (more than 6mm diameter), there are no very tortuous vessels, and vascular closure devices are available (Figure 9). Alternatively, the standard technique requires surgical preparation of the common femoral artery under local or general anesthesia. Major and minor postoper‐ ative vascular complications have been reported quite often in recent series [12,13] and some critical events (vessel dissections, ruptures or avulsions) might be catastrophic when not promptly and adequately treated.

**7.4. The trans-aortic approach**

**8. Results from the literature**

**8.1. Cribrier-Edwards valve**

massive bleeding limit this approach to selected patients.

In case of severe vascular disease and a concomitant contraindication to transapical proce‐ dures, an alternative, interesting, retrograde approach has been proposed: through an upper "J-shape" mini-sternotomy, the guidewire and the delivery system are inserted, retrograde‐ ly, into the ascending aorta and are secured with a double-string suture. TAVI is then done as a transfemoral procedure. The presence of "porcelain" aorta and the risk of postoperative

Indications for Transcatheter Aortic Valve Implantation

http://dx.doi.org/10.5772/53437

493

Cribier *et al.* did the first human implantation in 2002 [14]. The Edwards SAPIEN valve was approved for use in the European Union in November 2007 (for the transfemoral approach) and in January 2008 (for transapical delivery). In the Initial Registry of EndoVascular Im‐ plantation of Valves in Europe (I-REVIVE) trial, followed by the Registry of Endovascular Critical Aortic Stenosis Treatment (RECAST) trial, a total of 36 patients (mean (SD) Euro‐ SCORE 12 (2)) were included [15]. Twenty-seven patients underwent successful percutane‐ ous aortic valve implantation (23 antegrade, 4 retrograde). The 30-day mortality was 22% (6 of 27 patients), and the mean AVA increased from 0.60 ± 0.11cm2 to 1.70 ± 0.10cm2 (p<0.001). Importantly, this improvement in AVA was maintained up to 24 months followup [16]. Since these first trials, the Cribrier-Edwards prosthesis and the Edwards SAPIEN prosthesis have been used in numerous studies. Overall, acute procedural success is ach‐ ieved in 75–100% of the procedures, and 30-day mortality ranges between 8–50% in the pub‐ lished studies. Using the transapical technique and the Sapien valve, Walther et al. [17] has reported their initial multicenter results of 59 consecutive patients, which is the largest feasi‐ bility study published thus far. Procedural success using the transapical technique was ach‐ ieved in 53 patients. Thirty-day mortality was 13.6% and none of these were thought to be valve related as there was good valve function at autopsy. The overall procedural success of 1038 SAPIEN implants from 32 centers within the European SOURCE registry was 93.8%. The 30-day survival within SOURCE was 93.7% (transfemoral) and 89.7% (transapical) [18]. The 1-year survival of the cohort was 81.1% (transfemoral) and 72.1% (transapical), respec‐ tively. In cohort B of the PARTNER randomized trial, 179 patients receiving transfemoral SAPIEN aortic valve with 179 patients receiving standard medical therapy (including bal‐ loon aortic valvuloplasty), confirmed the superiority of transfemoral TAVI with regard to overall survival and cardiac functional status [19]. The Kaplan-Meier 1-year mortality from any cause was 30.7% (TAVI) versus 50.7% (standard medical therapy), corresponding to a 0.55 hazard ratio with TAVI (p<0.001). The fraction of surviving patients at 1-year, in New York Heart Association functional class III-IV, was lower in the TAVI group (25.2% versus 58%; p<0.001). Nevertheless, the TAVI group had a higher 30-day incidence of major stroke (5.0% versus 1.1%; p=0.06) and major vascular complications (16.2% versus 1.1%; p<0.001). Early and 1-year outcomes from the REVIVAL trial, which consisted of 55 patients with a

**Figure 9.** TAVI using the transfemoral approach

#### **7.3. The trans-subclavian approach**

Trans-subclavian access is an alternative retrograde pathway that has been recently ex‐ plored. It requires a surgical exposure of the left subclavian artery and an adequate minimal vessel inner diameter for 18F delivery systems (Figure 10). There are some advantages in us‐ ing this approach: firstly, the distance between the site of introduction and the aortic valve is short, compared with the transfemoral option, and it results in a steadier pathway. Second‐ ly, as long as the subclavian artery is intact, the trans-subclavian procedure can be done in case of a concomitant vascular disease involving the abdominal aorta or the legs, and it does not require a thoracotomy. Unfortunately, the presence of a patent internal mammary ar‐ tery, such as a diseased subclavian artery, in redo coronary surgery contraindicates this ap‐ proach. However, at this moment, this interesting approach remains "off-label" and is not yet formally recommended by the industry.

**Figure 10.** TAVI using the subclavian approach

#### **7.4. The trans-aortic approach**

are available (Figure 9). Alternatively, the standard technique requires surgical preparation of the common femoral artery under local or general anesthesia. Major and minor postoper‐ ative vascular complications have been reported quite often in recent series [12,13] and some critical events (vessel dissections, ruptures or avulsions) might be catastrophic when not

Trans-subclavian access is an alternative retrograde pathway that has been recently ex‐ plored. It requires a surgical exposure of the left subclavian artery and an adequate minimal vessel inner diameter for 18F delivery systems (Figure 10). There are some advantages in us‐ ing this approach: firstly, the distance between the site of introduction and the aortic valve is short, compared with the transfemoral option, and it results in a steadier pathway. Second‐ ly, as long as the subclavian artery is intact, the trans-subclavian procedure can be done in case of a concomitant vascular disease involving the abdominal aorta or the legs, and it does not require a thoracotomy. Unfortunately, the presence of a patent internal mammary ar‐ tery, such as a diseased subclavian artery, in redo coronary surgery contraindicates this ap‐ proach. However, at this moment, this interesting approach remains "off-label" and is not

promptly and adequately treated.

492 Calcific Aortic Valve Disease

**Figure 9.** TAVI using the transfemoral approach

**7.3. The trans-subclavian approach**

yet formally recommended by the industry.

**Figure 10.** TAVI using the subclavian approach

In case of severe vascular disease and a concomitant contraindication to transapical proce‐ dures, an alternative, interesting, retrograde approach has been proposed: through an upper "J-shape" mini-sternotomy, the guidewire and the delivery system are inserted, retrograde‐ ly, into the ascending aorta and are secured with a double-string suture. TAVI is then done as a transfemoral procedure. The presence of "porcelain" aorta and the risk of postoperative massive bleeding limit this approach to selected patients.
