Morphologic and angiographic analysis to assess the safety of a biodegradable mitral annuloplasty ring.

Background And Aim Of The Study: Although iatrogenic ischemic complications due to occlusion of the circumflex coronary artery following mitral ring annuloplasty are rare, they may be fatal if not recognized and treated promptly. The study aim was to assess the implantation safety of a novel biodegradable intra-annular mitral valvuloplasty ring in ex-vivo cadaveric human hearts.

Methods: Ten fresh-frozen human cadaveric hearts were washed, and filled with surgical gauze in order to mimic the heart's anatomic shape and position. Following left atriotomy, the biodegradable annuloplasty ring was implanted using the intra-annular implantation technique. Pre- and post-implantation coronary angiography was used to evaluate the dominance of the coronary circulation, and to assess coronary patency. The coronary arteries and veins were then filled with red and green latex solutions respectively, after which the hearts were fixed in 4% formaldehyde for four weeks. The distances between the annuloplasty ring, the coronary arteries, and coronary sinus were measured through perpendicular cuts at the levels of the anterolateral commissure (L-1), the mid-point of the posterior annulus (L-2), and the posteromedial commissure (L-3).

Results: Nine hearts had a right coronary artery dominance, and one had a balanced coronary circulation. None of the hearts demonstrated any abnormalities or occlusion of the circumflex coronary arteries after ring implantation. The mean distances between the circumflex coronary arteries and the ring were 7.2 +/- 2.7 mm, 11 +/- 2.4 mm, and 10.7 +/- 3.8 mm at L-1, L-2 and L-3, respectively. The mean distances between the coronary sinus and the ring were 11.8 +/- 3.4 mm, 9.8 +/- 2.3 mm, and 11 +/- 3.7 mm at L-1, L-2 and L-3, respectively. The implantation depth of the ring was 2-3 mm from the endocardial surface.

Conclusion: The present observations suggest that implantation of the intra-annular biodegradable annuloplasty ring is safe, as confirmed by angiography and measurement of the distances between the ring and the adjacent coronary vasculature.