Scanning electron microscopy evaluation of the Abiomed 5000 ventricular support system after clinical biventricular assistance.

Twenty-nine days after implantation of an Abiomed 5000 biventricular support system for otherwise intractable end-stage cardiomyopathy, the inner surfaces of the device were examined by means of scanning electron microscopy (SEM). SEM showed clean surfaces inside the blood sacs, with only rare fibrin deposits. There were platelet adhesions on the ventricular side of the artificial atrioventricular valves; no deposits were on the opposite side. Structural deterioration of the closing edge of the artificial valves could be seen. The tubing system was likewise covered by a uniform deposition of single platelets with no major thrombus formation. Postmortem examination of the patient, on the other hand, revealed gross thrombus formation inside both atria at the cannulation sites, despite efficient anticoagulation. We conclude that the Abiomed 5000 per se is unlikely to be the site of major thrombus formation leading to subsequent embolization after 660 h implantation. However, the structural integrity of the adapting areas of the leaflets may become a point of concern. Further research is necessary to improve the atrial cannulation technique in order to prevent the atrial thrombus formation demonstrated as the source of systemic embolization.