MULTI-LOOP TECHNIQUE FOR PAPILLARY MUSCLE RELOCATION IN ISCHEMIC MITRAL REGURGITATION

The appropriate surgical management of ischemic mitral regurgitation (IMR) is still highly debatable: valve replacement is often favoured over repair with ring annuloplasty (RA) because the former is associated with lower MR recurrence. The addition of a sub-valvular intervention, such as papillary muscle relocation (PMR), has been suggested to improve the durability of the mitral repair. Therefore, our aim was to examine the outcomes of a novel technique for PMR involving a multi-loop suture in the treatment of IMR.

Between 2017 and 2020, 9 patients with severe chronic IMR were enrolled into this case series: a multi-loop suture was used to address PMR in addition to ring annuloplasty. In brief, the multi-loop suture was prepared with Gore-Tex sutures, which was then anchored to the posteromedial papillary muscle, and buttressed with pledgets. The sutures attached to the loop were passed through the aspect of the annulus corresponding to the tethered segment, thus, serving as neo-chordae. Length was determined by saline test. Once regurgitation was absent on visual inspection of the saline test, the chordae were secured above the annulus with pledgets on the atrial side. Eight patients also received concomitant coronary artery bypass graft (CABG) procedure. Clinical and echocardiographic outcomes during the perioperative and follow-up periods were assessed. The mean follow-up was 15 +/- 8 months. One patient who had a pre-operative EuroSCORE of 8.25% died within the early post-operative period. The mean transmitral gradient at discharge was 3.8±1.4 mmHg. At follow-up, there was no mortality and cardiac-related readmissions, and only one patient had MR recurrence. The left ventricular end-systolic diastolic dimension was significantly lower at follow-up compared with pre-operative (6.1±4.6mm vs 5.6±0.9mm, P=0.03). A non-significant trend towards improvement was noted at follow-up compared with pre-operative for left ventricular end-diastolic volume (147.9 ± 61.2 ml vs 161.1 ± 46.6 ml, p=0.74), and left ventricular end-systolic volume (84.8 ± 42.6 ml vs 87.3 ± 35.9 ml, p=0.78). Despite the use of an undersized RA, mitral stenosis was not noted at latest follow-up, and the mean transmitral gradient of 3.6 ± 1.4 mmHg.

In patients with severe IMR, PMR with a multi-loop suture adjunctive to RA appears to offer excellent clinical and echocardiographic outcomes during follow-up of up to 2 years post-operatively. Nevertheless, these preliminary findings warrant further validation in a larger series of patients.