The Mitracut Technique To Prevent Outflow Tract Obstruction After Transapical Mitral Valve Replacement
Markus Mach, Tillmann Kerbel, Thomas Poschner, Anna Bartunek, Guenther Laufer, Martin Andreas.
Medical University of Vienna, Vienna, Austria.
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. 
LEGEND: Figure 1: A: A 26F Gore DrySeal Sheath shortened to 10 cm holding straight endoscopic scissors. B: 3D en-face view of a heavily calcified mitral valve with intact anterior mitral valve leaflet (AML). C: The red arrows indicate the open scissor tips before AML splitting. The green arrow indicates the guidewire used for consecutive TMVR D: Fluoroscopic view of the commissurotomy. E: Mid-esophageal long-axis view of the LVOT to guide the scissor blades (highlighted in red) between the AML and the incision depth. The wire used for consecutive TMVR is highlighted in green F: 3D en-face view displaying the correct position of the scissors, with only one of the two scissor blades visible under correct alignment. G: The red arrows indicate the scissor tips in the left atrium after AML splitting. The green arrow indicates the deep cut in the A2 segment of the AML.
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