Minimally Invasive, Tissue Engineering-Based Repair of Post Myocardial Infarction Mitral Regurgitation

Jonathan Leor, MD, Director, Neufeld Cardiac Research Institute Sheba Medical Center, Tel-Aviv University

Brief description of the research

Ischemic mitral regurgitation (MR) is a common complication of ischemic heart disease that conveys adverse prognosis after both myocardial infarction and coronary revascularization, more than doubling the risk of late death. We demonstrated in a murine and pig model of myocardial infarction that implantation of bioengineered alginate scaffolds grafted into the infarcted heart attenuates LV dilatation and failure compared with control. We can propose, therefore, that this acellular scaffold approach has the potential to reduce mitral leaflet tethering and ischemic MR by decreasing global end-systolic volume over which the mitral leaflets are stretched, as well as by locally reshaping the infarcted wall by making it thicker and less deformable.

We have attempted to develop a domestic pig model of ischemic MR and heart failure by alcohol ablation. Pigs were subjected to MI by transcoronary injection of ethanol 95% into the mid circumflex coronary artery or mid LAD coronary artery. An over-the-wire balloon catheter was advanced into the LAD or circumflex coronary artery. Ethanol 95% (1ml) was infused slowly (1 min) distally to the occluding balloon, through the central port of the balloon catheter. Echocardiography were performed on all animals before and 3 d and one month after MI induction. We experienced several problems during experiments: first, the infarcted pigs did not develop MR; second mortality of up to 50%; third in one third of the animals, the infarct related artery remained occluded. Thus, although ethanol approach could produce significant MI, it does not induce significant MR. To summarize, our preliminary results suggest that alcohol can be ued to generate MI and CHF in pig. However, we were unable to detect significant MR. Therefore, our model was not suitable to test our hypothesis.