Access Sites for TAVI: Patient Selection Criteria, Technical Aspects, and Outcomes

Abstract

During the last ten years, transcatheter aortic valve implantation (TAVI) has become a reliable and valid alternative treatment for elderly patients with severe symptomatic aortic valve stenosis requiring valve replacement and being at high or intermediate surgical risk. While common femoral arteries are the access site of choice in the vast majority of TAVI patients, in up to 15-20% of TAVI candidates this route might be precluded due to the presence of diffuse atherosclerotic disease, tortuosity or small vessel diameter. Therefore, in order to achieve an antegrade or retrograde implant, several alterative access routes have been described, namely trans-axillary, trans-aortic, trans-apical, trans-carotid, trans-septal, and trans-caval. The aim of this paper is to give a concise overview on vascular access sites for TAVI, with a particular focus on patient's selection criteria, imaging, technical aspects, and clinical outcome.

Keywords: TAVI; access; trans-aortic; trans-apical; trans-axillary; trans-carotid; trans-caval; trans-septal.

Figure 1

Bar plot reporting rates of transfemoral implants as compared to alternative accesses in national registries.

Figure 2

Three dimensional angio CT reconstruction obtained with the 3mensio software in a patient with severe aortic stenosis referred for TAVI (A). Snake view of the aorta and right iliacofemoral arteries (B) clearly shows diffuse calcific atherosclerotic disease precluding trans-femoral route. (C) shows diffuse tortuosity of the iliac arteries, while (D) the incidental finding of an infrarenal abdominal aneurysm. All the above mentioned findings might preclude a transfemoral approach.

Figure 3

Three dimensional reconstruction of the arterial system (A) and cross section of the common right femoral artery at the optimal puncture site (B). The artery shows a good caliber (exceeding 6.5 mm as evident from the yellow circle) and no calcifications. Moderate tortuosity of the superficial iliac artery is evident at both 3 D and angio reconstruction (C). In particular, the angio reconstruction allows for the fluoro guided detection of the optimal access site, based on its relationship with the femoral head.

Figure 4

Step by step approach for the transfemoral access. Once the common femoral artery has been deemed suitable for a trans-femoral approach due to the good caliber and the lack of anterior calcifications, the relationships with the femoral head (inferior border of the femoral head is highlighted in red), observed at the angio reconstruction, have to be described (A). Through a contralateral crossover, the pigtail is inserted in the common right femoral artery (B) and its position confirmed by contrast injection (C). Vessel puncture aiming at the anterior aspect of the femoral artery is then performed (D). Particular attention has to be paid in removing the pigtail before inserting the suture based closure devices with the consequent risk of catheter jailing and need for surgical removal (E).

Figure 5

Anatomy of the subclavian and axillary artery (A) and its relationship with the clavicle, the first rib and the medial border of the pectoralis minor. The first segment of the axillary artery (comprised between the two red lines) is usually the target for both surgical or percutaneous approaches. (B) shows the angiographic anatomy of the subclavian and axillary artery. (C) reports the surgical cut down for axillary artery with the vessel isolated by two yellow rubber bands. (D) shows a “Chimney approach” performed by means of a 15 cm × 8 mm GelwaveTM prosthesis, a gelatin sealed woven polyester peripheral vascular graft and a Check-FloVR PerformerTM 18 F Cook sheath (length 35 cm), routinely used for the transfemoral modified by cutting the distal portion in order to obtain an approximate length of 10–12 cm that could allow to accommodate the sheath inside the vascular graft without extending its distal edge into the axillary artery. (E) shows the navigation of a Medtronic Corevalve delivery system through the left subclavian artery.

Figure 6

(A) shows a 3D reconstruction of the left ventricle, aortic valve and ascending aorta in a patient with severe aortic stenosis. Lack of anterior calcifications of the aortic walls allowed for a transaortic approach. (B) shows an a case of a patients with extensive anterior aortic calcifications, a potential contra-indication for trans-aortic puncture. (C) the distance between the aortic entry site and the aortic valve annulus is of paramount importance for the valve release. A minimal distance of 6 cm is required for small delivery systems. The larger the valve size, the longer will be the length for delivery system retrieval.

Figure 7

Procedural steps in trans-apical approach. (A) surgical incision at the left fifth intercostal space and, after placement of a rib retractor and opening pericardium the apex is exposed. (B) Purse-string sutures reinforced by pledgets are placed at the apex and stabilized with a Tourniquet. (C) after apex is punctured within the purse-string sutures and a soft guidewire is advanced with an antegrade approach toward the aortic valve and positioned in the ascending aorta. Then, a conventional 18F sheath is advanced in the left ventricular cavity.