Platelet deposition on and calcification of bovine pericardial valve.

Abstract

Platelet deposition on bovine pericardial mitral valves was quantified in healthy adult mongrel dogs at 1, 14 and 30 days post-implantation and 24 h after i.v. injection of 400-500 microCi of autologous 111In-platelets. In vitro quantitation of platelet deposition on components of the prosthesis indicated maximal activity at one day with a successive decrease in activity at 14 and 30 days. At one day, platelet-associated radioactivity on the sewing ring was 3-4 times as great as on the leaflets, but at 14 and 30 days this had dropped to approximately half of the value on the leaflets. Calves underwent mitral valve replacement with a bovine pericardial valve. Thirty days post-operatively, 111Indium labeled labeled platelets were administered i.v.; 24 h later, calves were sacrificed and sections of each valve leaflet were analyzed for platelet and calcium deposition. Platelet deposition per mm2 of surface was greatest at the free edge of the leaflet, followed by the central zone and flexion point. Calves treated with sodium hydroxyethylene diphosphonate (5 mg kg-1 day-1 s.c.) had reduced platelet deposition but no reduced calcium content on the valves after 30 days compared with untreated calves. In flow chamber studies, platelet deposition from the heparinized blood of normal calves was significantly less on the smooth (inner) than on the rough (outer) surface of fixed bovine pericardium.