Clinical significance of PlA polymorphism of platelet GP IIb/IIIa receptors during long-term VAD support

Background. Although bleeding and thromboembolism remain major complications after implantation of ventricular assist devices (VADs), no standard anticoagulation protocols are available. Genetic polymorphism of platelet glycoprotein IIb/IIIa may contribute to the development of complications. The present study demonstrates a relationship between the PlA genotype and postoperative complications in patients implanted with pulsatile and axial flow VADs. Methods. The PlA genotype was determined in 41 consecutive patients treated with a VAD who received anticoagulation with phenprocoumon and aspirin. Pulsatile Novacor (Novacor Corp, Oakland, CA) and Berlin Heart VADs (Berlin Heart, Berlin, Germany) were implanted in 28 patients and the axial flow MicroMed DeBakey VAD (MicroMed Technology, Inc, Houston, TX) in 13. The relationship between the PlA genotype, the anticoagulation regime, and bleeding and thromboembolic events was analyzed. Results. There were no differences between patients with the A1A1 and A1A2 genotype regarding demographic characteristics, weight, or infection episodes. The international normalized ratio (INR), platelet activation tests, and doses of aspirin and dipyridamol before events were similar in both groups. Patients with the A1A1 genotype developed more bleeding complications (39% vs 0%, p = 0.021), while patients with the A1A2 genotype showed a tendency toward more thromboembolic events (13% vs 30%, p = 0.33). With regard to different types of VAD, patients with the axial flow DeBakey VAD and the A1A1 genotype developed significantly more bleeding complications (70% vs 0%, p = 0.033). Conclusions. In patients with a long-term VAD determination of PlA polymorphism and subsequent adjustment of the anticoagulation regime may lead to a reduction of bleeding and thromboembolic complications.