Balloon-Augmented Leaflet Modification With Bioprosthetic or Native Aortic Scallop Intentional Laceration to Prevent Iatrogenic Coronary Artery Obstruction and Laceration of the Anterior Mitral Leaflet to Prevent Outflow Obstruction: Benchtop Validation and First In-Man Experience

Abstract

Background: Bioprosthetic or native aortic scallop intentional laceration to prevent iatrogenic coronary artery obstruction (BASILICA) and laceration of the anterior mitral leaflet to prevent outflow obstruction (LAMPOON) reduce the risk of coronary and left ventricular outflow obstruction obstruction during transcatheter aortic valve replacement and transcatheter mitral valve replacement. Despite successful laceration, BASILICA or LAMPOON may fail to prevent obstruction caused by inadequate leaflet splay in patients having challenging anatomy such as very small valve-to-coronary distance, diffusely calcified, rigid leaflets, or undergoing transcatheter aortic valve replacement inside existing transcatheter aortic valve replacement. We describe a novel technique of balloon-augmented (BA) leaflet laceration to enhance leaflet splay.

Methods: We measured the incremental leaflet splay from BA-BASILICA in vitro. From November 2019 to March 2021, 16 patients underwent BA-BASILICA and 4 BA-LAMPOON at 3 centers.

Results: BA-BASILICA increased benchtop leaflet tip splay 17%, maximum splay angle 30%, and splay area 23%, resulting in a more rounded apex and larger effective area. Sixteen patients at risk for inadequate BASILICA leaflet splay, including 4 transcatheter aortic valve replacement inside existing transcatheter aortic valve replacement, underwent BA-BASILICA. All had successful leaflet laceration. One had coronary obstruction requiring immediate orthotopic stenting. Two underwent elective orthotopic coronary stenting through the transcatheter valve cells for leaflet prolapse without coronary ischemia. There were no deaths during the procedure or at 30 days. Four patients at risk for inadequate anterior mitral leaflet splay underwent BA-LAMPOON. All had successful target leaflet laceration without left ventricular outflow obstruction obstruction or procedural death. One died within 30 days.

Conclusions: BA leaflet laceration enhances leaflet splay in vitro and may allow transcatheter aortic valve replacement and transcatheter mitral valve replacement in patients otherwise ineligible for traditional BASILICA or LAMPOON due to challenging anatomy. Graphic Abstract: A graphic abstract is available for this article.

Keywords: electrosurgery; laceration; mitral valve; stents; transcatheter aortic valve replacement.

Figure 1:. In Vitro BA-BASILICA Modeling

Custom jig (a) to mount, traverse (a), optionally balloon dilatate (b, c) and lacerate pericardial “leaflets” in an electrosurgical bath and test balloon enlargement between traversal and laceration. Representative leaflet splay following BASILICA (d) and BA-BASILICA (e) laceration and subsequent implantation of a 26mm Sapien3. Schematic of a leaflet laceration (f) demonstrating splay measurements.

Figure 2:. In-vitro Modeling of Leaflet Splay after Benchtop BASILICA and BA-BASILICA in Two Common TAVR Devices

In-vitro data demonstrating increase in leaflet splay angle, tip splay distance, and leaflet splay area with BA-BASILICA. A) 29mm self-expanding THV following traditional BASILICA. B) 29mm self-expanding THV following BA-BASILICA. C) 26mm balloon expandable THV following traditional BASILICA. D) 26mm balloon expandable THV following BA-BASILICA. P value calculated using Student’s T-test.

Figure 3:. Demonstration of a BA-BASILICA and BA-LAMPOON Procedure

Representative degenerated bioprosthetic aortic valve, at high risk for left coronary obstruction, who underwent BA-BASILICA-TAVR. A) Traversal of the left coronary leaflet. B) Balloon dilatation of the target leaflet after traversal, before laceration. C) Post-deployment angiogram demonstrating patent left coronary, despite leaflet visibly touching the STJ. Representative patient with severe mitral stenosis, at high risk for LVOT obstruction, who underwent BA-LAMPOON-TMVR. D) Pre-procedural CT shows calcified basal AML. E) AML electrosurgical traversal. F) Lithotripsy pre-dilatation of the AML before laceration. G) After transcatheter mitral valve deployment. H) 3D CT reconstruction showing unobstructed cells and wide splay. (black = anterior leaflet split, white = Sapien3 valve frame, blue = annular calcification. Abbreviations: AML – anterior mitral leaflet, LCC – left coronary cusp, LVOT – left ventricular outflow tract, STJ – sinotubular junction, TMVR – transcatheter mitral valve replacement

Figure 4:. TAV-in-TAV Doppio BA-BASILICA

A, B) Pre-procedural CT demonstrating calcified leaflets portending high risk for bilateral coronary obstruction. C) Standard electrosurgical traversal of left and right coronary leaflets. D) Balloon dilatation of the target leaflets. E, F) Patent left and right coronaries after TAV-in-TAV. Adapted with permission from Greenbaum Abbreviations: LCC – left coronary cusp, LM – left main, RCC – right coronary cusp, RCA – right coronary artery, STJ – sinotubular junction

Figure 5:. Calcium Distribution Patterns for BA-BASILICA Patients

Patterns of heavy or diffuse calcification that might impede leaflet splay after laceration. Upper panels: Representative axial pre-procedural CT images of 6 BA-BASILICA patients with calcified target leaflets. Lower panels: Corresponding coronal images. Numbers correspond to patient number in Tables 2 and 3. Abbreviations: L – left coronary cusp, N – non coronary cusp, R – right coronary cusp,

Figure 6:. Acute Coronary Obstruction Salvaged with Orthotopic Left Main Stenting

Left main coronary obstruction despite successful BA-BASILICA in a patient with a small Mitroflow valve and a low coronary ostium, effaced sinus, and very narrow VTC. BA-BASILICA allowed successful left main PCI in an orthotopic fashion, through the cells of the THV. Abbreviations: PCI – percutaneous coronary intervention, THV – transcatheter heart valve, VTC – valve to coronary distance

Figure 7:. Calcium Distribution Patterns of Valve in MAC BA-LAMPOON Patients

Upper panels: Axial pre-procedural CT images of the annulus and AML. Lower panels: Corresponding cross-sectional images of the annulus and AML of the same patients. Numbers correspond to patient number in Table 5. Abbreviations: AML – anterior mitral leaflet

Figure 8:. Unsuccessful BASILICA and Fatal TAVR due to Rigid, Calcified Leaflet and Narrow VTC/VTSTJ Dimensions.

Fatal coronary obstruction despite BASILICA, which inspired development of balloon-augmented BASILICA. A) Pre-procedure CT showing a diffusely calcified left coronary leaflet, short left main, and small sinuses of Valsalva. B) Pre-procedure CT planning demonstrating high risk for coronary occlusion due to VTC and VTSTJ of 0. C) Autopsy findings with native leaflet pinned by TAVR valve, crushing rescue left main stent. D) Autopsy findings showing rigid, diffusely calcified leaflet with limited splay despite BASILICA. Abbreviations: L – left, LM – left main, R – right, SOV – sinus of Valsalva, TAVR – transcatheter aortic valve replacement, VTC – valve to coronary distance, VTSTJ – valve to sinotubular junction distance