Long-term safety and durability of percutaneous septal sinus shortening (The PS(3) System) in an ovine model.

OBJECTIVES: Chronic implants of the PS(3) system were conducted in an ovine model to assess durability and safety at up to 1 year follow-up. BACKGROUND: The long-term durability and safety of emerging percutaneous devices for functional mitral regurgitation remain largely unknown. METHODS: The PS(3) system (consisting of interatrial septal and great cardiac vein devices connected by an adjustable suture bridge) was placed in eight healthy adult sheep. The mitral annular septal-lateral dimension in systole (SLS) was acutely reduced by 15-20%. Animals were sacrificed at up to 12 months postimplant and characterized by intracardiac echocardiography, cardiac computed tomography (CT), and histopathology. In vivo forces exerted on the PS(3) bridge were measured by means of a novel load cell catheter. RESULTS: At 3, 6, and 12 months after implantation, intracardiac echocardiographic and CT showed the PS(3) systems to be intact without erosion and with overall sustained reductions in the SLS. Histopathologic assessment revealed each component correctly deployed in its respective target site without evidence of erosion, thrombus, or device fracture. The SLS was 26.5 +/- 1.7 mm preimplant, 22.0 +/- 1.4 mm post-PS(3) (17.0% reduction), and 22.0 +/- 2.1 mm at latest follow-up. Mean forces exerted on the bridge in vivo ranged from 1.16 N to 1.87 N. CONCLUSIONS: The PS(3) System demonstrated excellent biocompatibility without evidence of erosion, thrombosis, or perforation at up to one-year follow-up in this chronic healthy ovine model. Forces exerted in the PS(3) system were relatively modest and should contribute to the durability of the device.

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.