Transcatheter Aortic Valve Implantation (TAVI) in Bicuspid Anatomy

Abstract

Bicuspid aortic valve (BAV) stenosis, a common congenital condition, presents unique challenges for transcatheter aortic valve replacement (TAVI) due to anatomical variations like cusp morphology, coexisting aortopathy and calcification. TAVI offers a viable option for BAV patients with refinements in technique and technology, though ongoing research is essential to optimize patient-specific approaches and long-term results. Key considerations for TAVI in BAV include precise valve sizing, positioning, and the need for rigorous pre-procedural imaging to mitigate risks such as paravalvular leak and stroke. Early results show TAVI's safety and efficacy are comparable to surgery, though BAV patients undergoing TAVI often are exposed to higher rates of post-procedural pacemaker implantation. Emerging data on next-generation self-expandable (SE) and balloon-expandable (BE) valves reveal that while both offer success in this complex anatomical aortic valve variation, gaps remain in the long-term durability and management of BAV-related aortopathy. This review examines the latest advancements in TAVI for BAV, emphasizing how specialized approaches and device selection address BAV's complexities.

Keywords: TAVI; aortic stenosis; bicuspid.

Figure 1

Suggested classification of the BAV anatomy (modified by Michelena et al., Ref. [4]): The consensus proposes a relatively simple classification according to three (3) components of the anatomy: sinuses, cups and the presence or absence of raphe. (“?” Indicates that incidence of the cases are not precisely known).

Figure 2

Case illustration of a patient with BAV who underwent TAVI: (A) computer tomography angiography (CTA), which reveals typical BAV anatomy Type 3 (white arrow) according to the classification presented in Figure 1; (B) the dimensions of the appropriate TAVI size were measured at 4 mm above the aortic annulus. Cinematic representation: 1. baseline angiography, 2. pre-dilatation, 3. SE valve positioning, 4. SE final position and angiography demonstrating no AR, 5. Successful access site closure.

Figure 3

Homogenous and circumferential expansion of a TAVI valve in a tricuspid aortic valve anatomy, which results in a wider distention of the TAVI frame and, subsequently, a larger bio-prosthetic aortic valve area. The homogenous opening of the native valve results in the better apposition of the TAVI valve and better sealing, with less PVL. In a bicuspid anatomy (this is an example of a single raphe BAV, Sievers Type 1 L-R), the presence of a raphe between the cusps may lead to the insufficient separation of the cusps, leading to non-homogeneous TAVI frame expansion. This leads to a smaller valve orifice area and an oval-shaped valve configuration, which may induce early valve degeneration. Furthermore, the incomplete and non-circumferential apposition of the valve’s skirt may lead to incomplete sealing and subsequently a large area for PVL (BAV: Bicuspid Aortic Valve, PVL: Paravalvular leak).

Figure 4

Life Span Strategy (LSS): In patients where surgery is not considered as the only option, due to relative contraindications, deciding how to treat these patients depends on whether the ascending aorta aneurysm requires surgical restoration (✅) or not (⛔). If a surgical correction is required (✅), then the patient may be treated with the initial combined restoration of the ascending aorta and aortic stenosis, and then with TAVI in a bioprosthetic and re-TAVI if needed, at a later stage. In the latter case (⛔), the patient may initially have a TAVI procedure, followed by a surgical combined procedure with ascending aorta and aortic valve replacement in the case of TAVI restenosis and/or ascending aorta aneurysm enlargement. At a later stage, the patient may require a TAVI in a bioprosthetic valve procedure.