Combined Oral Anticoagulant and Antiplatelet Therapy And Bleeding Risk

Abstract number: P2218

Poli D, Antonucci E, Cecchi E, Ilari I, Alessandrello Liotta A, Lapini I, Cellai AP, Gensini GF, Abbate R, Prisco D

In selected patients oral anticoagulant therapy (OAT) cannot sufficiently prevent thrombotic events and the association of antiplatelet therapy (APT) is required. This practice is debatable because of increased risk of bleeding. Aim of our study was to evaluate the rate of adverse events in patients receiving OAT+APT treatments. We studied 1596 consecutive unselected patients (942 males and 654 females; mean age 64 ± 13.1 years; follow-up 3364 patient-years), referred to our Anticoagulation Clinic for OAT monitoring. Among these patients, 44 (33 males and 11 females; mean age 64.6 ± 11.7 years) received also APT, for a total period of 115 patient-years. Patients received both treatments for different indications: mechanical prosthetic heart valves (13), arterial vascular disease (12), coronary artery disease (13), atrial fibrillation with embolic complication (4), other indications (2). Looking at the quality of OAT, time spent within, above and below the intended therapeutic range was similar in treated or not with APT (67%, 15% and 18% in the whole population and 70%, 15% and 15% in patients with APT). 2/44 APT patients had major bleeding events (1.7/100 patient-years), none was fatal. In all the other patients we recorded 36/1552 major bleeding events with a similar rate of incidence (1.1/100 patient-years), 3 were fatal (P= 0.5). 9/44 APT patients had major thrombotic events (rate 7.8/100 patient-years), none was fatal. In all the other patients, we recorded 95/1552 major thrombotic events (rate 2.9/100 patient-years), 3 were fatal. This difference was statistically significant [RR 2.6 (1.1–5.3 95% CI) P= 0.01], and may reflect the higher thrombotic risk that lead to the choice of adding APT to OAT. In conclusion, patients at high thrombotic risk who received OAT associated with APT seems not to be at significantly higher risk of serious bleeding.