Septal-lateral annular cinching abolishes acute ischemic mitral regurgitation

Abstract

Objective: Ring annuloplasty prevents acute ischemic mitral regurgitation in sheep, but it also abolishes normal mitral annular and posterior leaflet dynamics. We investigated a novel surgical approach of simple septal-lateral annular cinching with sutures to treat acute ischemic mitral regurgitation. Methods: Nine adult sheep underwent implantation of multiple radiopaque markers on the left ventricle, mitral anulus, and mitral leaflets. A septal-lateral transannular suture was anchored to the midseptal mitral anulus and externalized to a tourniquet through the midlateral mitral anulus and left ventricular wall. Open-chest animals were studied immediately postoperatively. Acute ischemic mitral regurgitation was induced by means of proximal left circumflex artery snare occlusion, and 3 progressive steps of septal-lateral annular cinching (each 2-3 mm suture tightening for 5 seconds) were performed with the transannular suture. Biplane videofluoroscopy for 3-dimensional marker coordinates and transesophageal echocardiography were performed continuously before and during left circumflex ischemia and septallateral annular cinching. Results: Acute left circumflex ischemia caused ischemic mitral regurgitation (+0.5 ± 0.4 [baseline] vs +2.0 ± 0.7 [ischemia]; P = .005; scale, +0-4), which decreased progressively with each step of septal-lateral annular cinching and was eliminated during the third step (ischemic mitral regurgitation, +0.6 ± 0.5; P = not significant vs baseline). The third step of septal-lateral annular cinching decreased the septal-lateral diameter by 6.0 ± 2.6 mm (P = .005); however, mitral anulus area reduction (8.5% ± 1.0% and 6.9% ± 1.9% for ischemic mitral regurgitation and septal-lateral annular cinching step 3, respectively; P = .006) and posterior leaflet excursion (50° ± 9° and 44° ± 11° for regurgitation and annular cinching step 3, respectively; P = .002) throughout the cardiac cycle were affected only mildly. Normal mitral annular 3-dimensional shape was maintained with septal-lateral annular cinching. Conclusions: Isolated 22% ± 10% reduction in mitral annular septal-lateral dimension abolished acute ischemic mitral regurgitation in normal sheep hearts while allowing near-normal mitral annular and posterior leaflet dynamic motion. Septallateral annular cinching may represent a simple method for the surgical treatment of ischemic mitral regurgitation, either as an adjunctive technique or alone, which helps preserve physiologic annular and leaflet function.