The Mitracut Technique To Prevent Outflow Tract Obstruction After Transapical Mitral Valve Replacement

Authors: Markus Mach, Tillmann Kerbel, Thomas Poschner, Anna Bartunek, Guenther Laufer, Martin Andreas.
Medical University of Vienna, Vienna, Austria.
Abstract:

BACKGROUND: This study sought to report the first-in-human experience with a new minimal-invasive surgical hybrid technique to split the
anterior mitral valve leaflet (AML) and prevent iatrogenic left ventricular outflow tract (LVOT) obstruction during transapical transcatheter
mitral valve replacement.

METHODS: Between November 2022 and December 2022, four patients were treated with the endoscopic mitral-leaflet cutting (Mitra-Cut)
technique before undergoing a transapical mitral valve replacement using a self-expandable transcatheter heart valve system. All patients
were at potential risk for iatrogenic LVOT obstruction. A 26F Gore DrySeal sheath (W.L. Gore & Associates, Inc., Flagstaf, AZ, USA) was
shortened to an appropriate length and inserted via the transapical access site. After insertion of straight endoscopic scissors (CERAMO HCR,
MRT-2, Fehling Instruments, Karlstein am Main, Germany; blade length: 10mm, shaft diameter: 5mm), the anterior mitral leaflet was cut in
the A2 segment under transesophageal echocardiographic guidance. The result was assessed using transesophageal echocardiography; the
transcatheter mitral valve replacement was then performed in a standardized fashion.

RESULTS:The anterior mitral valve leaflet was successfully split in all cases. The mean procedural time for the Mitra-Cut was 2.5 ± 0.5
minutes. Procedural success for the TMVR procedure was 100%, with no systolic anterior leaflet motion, left ventricular outflow tract
obstruction, or other major complications. At hospital discharge, the echocardiographic evaluation revealed trace residual mitral
regurgitation in 2 patients and no MR in 2 patients. The mean transvalvular mitral and aortic gradients were 3.3 ± 1.0 and 5.2 ± 2.3 mmHg,
respectively. Patients were transferred to the normal ward either on the same day (n=2) or on the first postoperative day (n=2) and
discharged after 9±2 days after TMVR, with all patients being New York Heart Association functional class II.

CONCLUSIONS:The Mitra-Cut technique is a safe, efective, fast, and simple alternative to the LAMPOON procedure for prevention of
iatrogenic LVOT obstruction in patients undergoing transapical TMVR. Because it is primarily an echo-guided procedure that does not require
additional vascular access, the radiation exposure and the risk for vascular complications are probably reduced. Further studies with a larger
number of patients and longer follow-up are warranted.