Extracardiac approach to functional mitral regurgitation: a cost-effective approach to addressing heart failure

To cite: Padmanabhan C, Jagannathan R, Talluri K, et al. BMJ Innov Published Online First: [please include Day Month Year] doi:10.1136/bmjinnov-2016000115 ABSTRACT Background Heart failure is frequently associated with severely impaired ventricular function and manifests often with functional mitral regurgitation (FMR). This is a complex syndrome that is primarily due to abnormal function of the ventricular muscle in the presence of normal mitral leaflets and annulus. Present surgical treatment options approach the problem through mitral valve annulus and leaflets, rather than ventricular muscle. We developed a concept that provides a ventricular solution to this problem. Methods After early proof-of-concept studies with polyester mesh, the BACE (Basal Annuloplasty of the Cardia Externally) device was developed along these lines—an adjustable silicone band that is implanted by means of slim polyester belt loops, and secured at the base of the heart. This device can be adjusted remotely under echocardiographic guidance, by inflating the inbuilt balloons that are connected to subcutaneous ports. Initial evaluation in animals showed long-term device safety. Safety and efficacy studies were performed in patients at 4 centres in India. They all underwent coronary artery bypass graft and implantation of the BACE device to correct mitral regurgitation (MR) on a beating heart. Results The animal evaluation included 2 components—a group of animals with severe FMR induced by rapid ventricular pacing with long-term implants to establish safety and efficacy and a group of normal animals implanted in a GLP laboratory to ensure device safety for regulatory purposes. The patient population included 11 patients, with a mean age of 58. The mean presurgical left ventricular ejection fraction was 31.8%. The mean MR grade (3.3±0.6) improved to 0.6±0.5 post-BACE implantation (p<0.05). The mean number of bypass grafts was 2.5. The effective improvement in MR was sustained at 6 months in the patients that had completed that duration of the study. All patients were followed up after surgery clinically and echocardiographically. Heart failure symptoms were reduced in all surviving patients with all of them being in NYHA Class I or II at 1-year follow-up. Conclusions Epicardial application and adjustment of the BACE device can be performed safely on a beating heart with effective reduction in FMR and sustained benefit in preventing heart failure progression. This early clinical trial shows encouraging results with this approach. This is the first epicardial device for treatment of FMR that can be remotely adjusted. This capability suggests that correction of MR under echocardiograph guidance is feasible.