Microsizing Using Inside Suture Placement. A Simple and Versatile Technique for Precision Adjustment of Ring Annuloplasties

INTRODUCTION: A new and simple technique for eliminating residual leaks during mitral annuloplasty, called microsizing, is described. METHODS: Microsizing is performed by moving one or more annuloplasty sutures from the outside to the inside of the prosthetic ring. This maneuver advances discrete segments of the annulus toward the opposing leaflet by a distance equal to the thickness of the ring (approximately 3 mm). Microsizing is a simple method for precision adjustment of annular shape and size to eliminate focal gaps, regardless of the cause. RESULTS: A series of 63 consecutive patients with moderate to severe mitral regurgitation (MR) were repaired over a 10 year period, all with intraoperative transesophageal echocardiography guidance. No patient required valve replacement (repair success rate 100%). Concomitant (non-mitral valve) procedures were performed in 53 patients (84.1%). Fifty patients (79.3%, Group 1) underwent successful repair using traditional suture placement in the prosthetic ring. Thirteen patients (20.6%, Group 2) had one or more sutures repositioned to the inside of the ring ("micro-sized") as a new strategy to eliminate residual leaks. Mean post repair MR grade was lower when microsizing was used (0.15 for Group 2 versus 0.30 for Group 1). No micro-sized patient experienced systolic anterior motion (SAM) or mitral stenosis. There were no repairs with greater than trace MR, late ring dehiscences, recurrent regurgitation, or reoperation in the entire series. There was one death (1.6%) in a non-micro-sized patient from intra-operative abdominal hemorrhage secondary to an IABP complication. CONCLUSION: Microsizing is a simple variation of suture placement that allows custom shaping of the mitral annulus by advancing selected portions toward the opposing leaflet, eliminating gaps, and improving coaptation. This technique is safe, simple, and reproducible without causing stenosis, SAM, or late failure.