Percutaneous septal sinus shortening: a novel procedure for the treatment of functional mitral regurgitation.

Background: The septal-to-lateral (SL) mitral annular diameter is increased in functional mitral regurgitation (MR). We describe a novel percutaneous technique (the percutaneous septal sinus shortening system) that ameliorates functional MR in an ovine model.

Methods And Results: Sheep underwent rapid right ventricular pacing to obtain moderate to severe functional MR with SL enlargement. The percutaneous septal sinus shortening system was placed via standard interventional techniques consisting of a bridge (suture) element between interatrial septal wall and great cardiac vein anchors. Through progressive tensioning of the bridge element, direct SL shortening was achieved. Sheep underwent short-term (n=19) and long-term (n=4) evaluation after device implantation. In short-term studies, SL diameter decreased an average of 24% (32.5+/-3.5 to 24.6+/-2.4 mm; P<0.001), and MR grade significantly improved (2.1+/-0.6 to 0.4+/-0.4; P<0.001). Despite continued rapid pacing, chronic device implantation resulted in durable SL shortening (30.4+/-1.9 mm before implantation to 25.3+/-0.8 mm at 30 days; P=0.01) and MR reduction (1.8+/-0.5 before implantation to 0.2+/-0.1 at 30 days; P=0.01). Increased cardiac output, decreased wedge pressure, and decreased brain natriuretic peptide levels were observed in animals undergoing long-term device implantation.

Conclusions: The percutaneous septal sinus shortening system is effective in ameliorating functional MR in an ovine tachycardia model. The procedure, which uses standard catheter techniques, can be deployed largely under fluoroscopic guidance. The unique bridge element appears durable and allows direct and precise SL shortening to a diameter optimal for MR reduction.