Abstract 6150: Dynamic Characterization of Mitral Valve Anterior Leaflet Perfusion Pattern
Previous histologic and static-staining studies have confirmed the existence of blood vessels in the anterior mitral valve leaflet (AML) and chordae, but little is known about the dynamic pattern of leaflet perfusion. We investigated the pattern and source of AML perfusion in an ovine model. Fluorescein angiograms were obtained in 17 ovine hearts immediately after heparinization and cardioplegic arrest using non-selective left coronary artery (LCA) and selective left anterior descending (LAD), proximal, mid and distal left circumflex (LCx) perfusion. Serial photographs using a flash/filter system to optimize fluorescence were obtained through a left atriotomy. The proximal half of the AML has a rich vascular supply. A loop of vessels is consistently observed in the mitral annulus and AML: Vessels run along the annulus, particularly that subtending the AML, extend out to the sites of second-order chordae (SC) insertion (Fig⇓.*) and create anastomoses between these insertion sites (Fig. A⇓). SC contribute perfusion to the AML and the anastomotic loop (Fig. B⇓). Selective perfusion of the LAD or proximal LCx artery (ligated before first OM) did not perfuse the AML (n=6). Perfusion of the mid and distal LCx (n=7) consistently supplied the AML via SC insertion sites (*) and annular branches. The AML is perfused by vessels that run through the SC and annulus simultaneously, which then create a communicating arcade in the AML. These vessels originate from the mid-and distal portions of the LCx artery in Ovine hearts. Loss of perfusion from microvascular disease or chordal cutting could have adverse implications that need to be addressed in further studies.