Transcatheter Laceration of Aortic Leaflets to Prevent Coronary Obstruction During Transcatheter Aortic Valve Replacement: Concept to First-in-Human

Abstract

Objectives: This study sought to develop a novel technique called bioprosthetic or native aortic scallop intentional laceration to prevent coronary artery obstruction (BASILICA).

Background: Coronary artery obstruction is a rare but fatal complication of transcatheter aortic valve replacement (TAVR).

Methods: We lacerated pericardial leaflets in vitro using catheter electrosurgery, and tested leaflet splaying after benchtop TAVR. The procedure was tested in swine. BASILICA was then offered to patients at high risk of coronary obstruction from TAVR and ineligible for surgical aortic valve replacement. BASILICA used marketed devices. Catheters directed an electrified guidewire to traverse and lacerate the aortic leaflet down the center line. TAVR was performed as usual.

Results: TAVR splayed lacerated bovine pericardial leaflets. BASILICA was successful in pigs, both to left and right cusps. Necropsy revealed full length lacerations with no collateral thermal injury. Seven patients underwent BASILICA on a compassionate basis. Six had failed bioprosthetic valves, both stented and stent-less. Two had severe aortic stenosis, including 1 patient with native disease, 3 had severe aortic regurgitation, and 2 had mixed aortic valve disease. One patient required laceration of both left and right coronary cusps. There was no hemodynamic compromise in any patient following BASILICA. All patients had successful TAVR, with no coronary obstruction, stroke, or any major complications. All patients survived to 30 days.

Conclusions: BASILICA may durably prevent coronary obstruction from TAVR. The procedure was successful across a range of presentations, and requires further evaluation in a prospective trial. Its role in treatment of degenerated TAVR devices remains untested.

Keywords: bioprosthetic heart valve failure; coronary artery obstruction; structural heart disease; transcatheter aortic valve replacement; transcatheter electrosurgery.

Figure 1.. Illustrations of coronary obstruction and prevention by BASILICA.

In normal TAVR performed in a capacious aortic root, blood flows unrestricted around valve leaflets into coronary arteries. In patients with a crowded sinus and low lying coronary arteries, coronary blood flow is obstructed by the bioprosthetic valve leaflets after TAVR. After BASILICA, blood flows through the open cells of the transcatheter heart valve unimpeded into the coronary artery.

Figure 2.. Illustration of the BASILICA procedure.

(A) a catheter directs an electrified guidewire through the base of the left aortic cusp into a snare in the left ventricular outflow tract; (B) after snare retrieval, the mid-shaft of the guidewire is electrified to lacerate the leaflet (C); (D) the leaflet splays after TAVR permitting coronary flow.

Figure 3.. Benchtop simulation of BASILICA

Two different transcatheter heart valves (23mm Sapien 3, top, and 26mm Evolut Pro, bottom) implanted in 25mm Mitroflow before (left) and after (right) the leaflet is cut with a scalpel.

Figure 4.. Necropsy after BASILICA in an animal

Animal necropsy viewed from the aorta showing a split left coronary cusp in line with the left coronary artery ostium. NCC = non-coronary cusp; LCC = left coronary cusp; RCC = right coronary cusp.

Figure 5.. BASILICA for TAVR with Sapien 3 in failed Mitroflow valve.

A) left coronary injection demonstrates a high risk of left coronary obstruction from the Mitroflow leaflet (double headed arrow); B) Co-axial catheters direct an electrified guidewire through the left coronary leaflet of the Mitroflow valve into the left ventricular outflow tract snare; C) laceration with radiofrequency concentrated at the kinked mid-shaft of the Astato guidewire (arrow); D) left cusp injection with flow through split leaflet and patent left coronary artery that would otherwise have been obstructed. LCA = left coronary artery; LCC = left coronary cusp.

Figure 6.. BASILICA and TAVR with Sapien 3 for native aortic stenosis

A) An electrified guidewire traverses native left coronary cusp leaflet into the LVOT snare; B) leaflet laceration through exposed kinked guidewire shaft (arrow); C) aortic root angiography showing coronary flow in a low lying coronary artery that may have been obstructed without BASILICA.

Figure 7.. Double BASILICA and TAVR with Sapien 3 for failed Magna valve

A) Heavily calcified leaflets, especially the left coronary cusp. B) Left coronary height is low at 3.4mm. C) Both left and right VTC are low at 3.3mm. D) An electrified guidewire traverses the left coronary leaflet of a Magna valve; E) The left coronary leaflet guidewire has been externalized to form a loop and a second electrified guidewire traverses the right coronary leaflet; F) Loops formed around both left (white arrow) and right (black arrow) coronary cusps, ready for sequential laceration; G) After TAVR a high pressure balloon is inflated to crack the bioprosthetic valve to improve hemodynamics; H) The bioprosthetic valve has been fractured at the site of the black arrow; I) Angiography demonstrates good flow to both coronary arteries that may otherwise have been completely obstructed. LCC= left coronary cusp; RCC = right coronary cusp; NCC = non-coronary cusp; RCA = right coronary artery; LCA = left coronary artery; VTC = virtual transcatheter valve to coronary distance.

Figure 8.. Transoesophageal echocardiography during BASILICA and TAVR with Sapien 3 for failed Sorin Solo Freedom valve

A) Echocardiography view showing the traversal catheter is aligned at the base of the left coronary cusp (upward arrow). A snare catheter is positioned across the valve (downward arrow); C) The laceration in the left coronary cusp is seen (arrow), adjacent to the left coronary artery ostium. LCA = left coronary artery

Figure 9.. CT images following BASILICA and TAVR with SAPIEN 3 (A-C) and Evolut Pro (D-E).

A-B) A narrow neo-sinus (double-headed arrow) maintains flow to the right coronary artery but the left sinus (B-C) is completely effaced. D-E) The left coronary artery was at risk of occlusion but there is adequate filling following BASILICA.