Modification of a hybrid technique for closure of muscular ventricular septal defects in a pig model

Closure of muscular ventricular septal defects (mVSDs) beyond the moderator band is still a challenge for both surgeons and interventional cardiologists. We evaluated a new technique in a pig model for hybrid patch closure of mVSDs via 2 stab wound incisions in the left ventricle (LV) without cardiopulmonary bypass.

Ten pigs underwent left anterolateral thoracotomy to expose the LV. mVSDs were created via a stab wound incision of the lateral wall of the LV under epicardial echocardiographic control. The patch system was forwarded through a second puncture of the LV apex and positioned in front of the mVSD. The stapler for fixation of the patch was introduced through the same incision as used for VSD creation. Finally, the patch was attached to the septum with nitinol anchors under epicardial echocardiographic and fluoroscopic guidance. Finally, detailed echocardiographic evaluation was done. All hearts were explanted, and macroscopic evaluation was done, either immediately after patch implantation (n = 4) or after 90 days (n = 6).

mVSD creation was successful in all pigs. Closure of mVSDs was successful in 8 of 10 pigs, as confirmed by echocardiography, hemodynamic measurements, and macroscopic examination. One patch embolized through the mVSD into the pulmonary artery because of insecure fixation, and 1 animal died during the procedure because of ventricular fibrillation. The final echocardiographic evaluation revealed good LV function and no damage to the valves.

Closure of mVSDs can be successfully performed in a hybrid technique on the beating heart with 2 stab wound incisions; however, further modifications need to be developed before clinical application.