Abstract 2870: RING+STRING - Successful Repair Technique for Ischemic Mitral Regurgitation with Severe Leaflet Tethering
Residual/recurrent mitral regurgitation (MR) is observed in 30% of patients after undersized ring annuloplasty (RING) for ischemic MR. RING addresses primarily annular dilatation, but does not correct severe leaflet tethering due to papillary muscle (PM) displacement. We have performed a new repositioning method of the posterior PM using a transventricular suture (STRING), which is used in addition to standard repair (RING) and applied under transesophageal echocardiography (TEE) guidance in the loaded beating heart. Patients with tenting height exceeding 10mm were identified as high-risk patients for repair failure. In these patients (n=30, age 67±11 years, EF 37±14%, MR 3.2±0.4) undersized RING was combined with the adjunctive STRING technique. After CABG (3.1±1.1 grafts) and RING (partial flexible ring, median 29mm), a horizontal aortotomy was performed to expose the subvalvular mitral apparatus. A Teflon-pledgeted 4 – 0 polytetrafluoroethylene suture was anchored in the head of the posterior PM and then passed through the aorto-mitral continuity underneath the commissure between the non- and left-coronary aortic cusps and exteriorized through the aortic wall. During termination of cardiopulmonary bypass, this suture was tied under TEE guidance in the loaded beating heart. Tenting height (14±2mm to 5±1mm*) and tenting area (3.9±0.9 to 0.9±0.2*) decreased. The distance between posterior PM and aorto-mitral continuity was reduced (44±4mm to 36±3mm*). MR improved (3.2±0.4 to 0.5±0.5*) and remained stable (1.1±0.5) within medium-term follow-up (median 18 months, range 1– 41 months, freedom from reoperation 100% and freedom from MR>II 100% at 3 years). Two patients died in hospital, while 3 patients died during follow-up (lung cancer, endometrial cancer, sudden cardiac death) with stable mitral valve function. End-diastolic (62±7 to 55±8*) and end-systolic (48±9 to 43±8*) LV diameters decreased. (*p<0.05, paired t-test) Repositioning of the posterior PM neutralizes the ventricular component of ischemic MR. The combination of RING+STRING allows successful and reproducible repair in patients with high risk of repair failure leading to stable mitral valve function and LV reverse remodeling.