Anterior Leaflet Laceration to Prevent Ventricular Outflow Tract Obstruction During Transcatheter Mitral Valve Replacement

Abstract

BACKGROUND Left ventricular outflow tract (LVOT) obstruction is a leading cause of mortality and exclusion from transcatheter mitral valve replacement (TMVR). Intentional laceration of the anterior mitral valve leaflet to prevent LVOT obstruction (LAMPOON) is a transcatheter mimic of surgical chord-sparing leaflet resection. OBJECTIVES The purpose of this prospective multicenter trial was to study LAMPOON with transseptal (Edwards Lifesciences, Irvine, California) TMVR in annuloplasty rings or native mitral annular calcification (MAC). METHODS Subjects at high or extreme surgical risk and prohibitive risk of LVOT obstruction from TMVR were included. Eligibility was modified midtrial to exclude subjects with threatened LVOT obstruction from a Sapien 3 valve fabric skirt. The primary endpoint was procedure survival with successful LAMPOON, with successful TMVR, without reintervention, and with LVOT gradient <30 mm Hg (“optimal”) or <50 mm Hg (“acceptable”). Secondary endpoints included 30-day mortality and major adverse cardiovascular events. There was universal source-data verification and independent monitoring. All endpoints were independently adjudicated. Central laboratories analyzed echocardiogram and CT images. RESULTS Between June 2017 and June 2018, 30 subjects were enrolled equally between the MAC and ring arms. LAMPOON traversal and midline laceration was successful in 100%. Procedure survival was 100%, and 30-day survival was 93%. Primary success was achieved in 73%, driven by additional procedures for paravalvular leak (10%) and high-skirt neo-LVOT gradients observed before a protocol amendment. There were no strokes. CONCLUSIONS LAMPOON was feasible in native and annuloplasty ring anatomies in patients who were otherwise ineligible for treatment, with acceptable safety. LAMPOON was effective in preventing LVOT obstruction from TMVR. Despite LAMPOON, TMVR using Sapien 3 in annuloplasty rings and MAC still exhibits important limitations. (NHLBI DIR LAMPOON Study: Intentional Laceration of the Anterior Mitral Leaflet to Prevent Left Ventricular Outflow Tract Obstruction During Transcatheter Mitral Valve Implantation; NCT03015194)

Acute fulminant hemolysis after transcatheter mitral valve replacement for mitral annular calcification

“…TMVR may lead to hemolysis by shear stress placed on RBCs passing through non‐endothelialized PVL channels or through cells of the mitral prosthesis that may protrude in the LVOT. The incidence of hemolysis in prior series of TMVR has been reported between 4 and 40% 3,7,8 . This wide range is likely related to differences in definitions of hemolysis and TMVR technique.…”

BATMAN—Savior or vigilante?

“…1 LAMPOON was successful in all patients irrespective of anatomy and calcification and 30-day survival in patients with a mean neo-LVOT of 81 mm 2 or mean anterior mitral leaflet length of 28 mm was 93%. 1 However, LAMPOON was unable to prevent obstruction from the covered valve skirt in cases where the skirt neo-LVOT was reduced. 2 Pre-emptive alcohol septal ablation was studied in a retrospective registry with self-reported endpoints.…”

“…Preventative strategies include percutaneous laceration of the anterior mitral leaflet (LAMPOON), pre‐emptive alcohol septal ablation, and transatrial surgical anterior mitral leaflet resection. Of these, the best evidence is for LAMPOON, which has been studied prospectively in a clinical trial with independent endpoint adjudication and core laboratory image analysis . LAMPOON was successful in all patients irrespective of anatomy and calcification and 30‐day survival in patients with a mean neo‐LVOT of 81 mm 2 or mean anterior mitral leaflet length of 28 mm was 93% .…”

“…Of these, the best evidence is for LAMPOON, which has been studied prospectively in a clinical trial with independent endpoint adjudication and core laboratory image analysis . LAMPOON was successful in all patients irrespective of anatomy and calcification and 30‐day survival in patients with a mean neo‐LVOT of 81 mm 2 or mean anterior mitral leaflet length of 28 mm was 93% . However, LAMPOON was unable to prevent obstruction from the covered valve skirt in cases where the skirt neo‐LVOT was reduced .…”

Hemodynamics rounds: Hemodynamics of mitral valve interventions

“…For instance, to overcome the risk of left ventricular outflow tract obstruction in certain cases of TMVR (e.g., mitral annular calcification), recent techniques have incorporated deliberate anterior mitral valve leaflet laceration. This technique sacrifices the native anterior leaflet through direct incision via percutaneous techniques, inducing severe mitral regurgitation but allowing for reduced risk of anterior leaflet displacement and postprocedural left ventricular outflow tract obstruction with valve replacement . In this setting, invasive hemodynamic monitoring confirms effective leaflet laceration in real time, facilitates further intraprocedural support (e.g., deployment of an intraaortic balloon pump), and guides valve replacement (Figure ).…”