Platelet activation markers in patients with heart assist device

Clinical use of heart assist devices is often associated with thromboembolic complications. We hypothesized that platelets may be activated in patients receiving assist devices and examined expression of the platelet activation markers CD62, CD63, and thrombospondin using flow cytometry in eight patients with Novacor left ventricular assist system (LVAS) or Berlin Heart. Patients with end-stage heart failure had elevated expression of platelet activation markers before insertion of the assist device. While CD62 (P < 0.05) and thrombospondin expression (n.s.) decreased by the 14th postoperative day, the CD63 expression remained elevated (n.s.). A good correlation was found between CD62 and thrombospondin expression (r = 0.72). Bleeding time ex vivo indicated platelet dysfunction during the first 4 weeks after implantation. No relation between expression of platelet activation markers and bleeding time ex vivo were found. In conclusion, expression of the platelet activation markers CD62, CD63, and thrombospondin is increased in patients with end-stage heart failure before device placement and shows prolonged elevation during the assist period. Future studies in larger patient populations are necessary to identify new and specific markers of platelet activation in this clinical setting.