The effect of dipyridamole on the thrombocyte count and bleeding tendency in open-heart surgery.

The effect of dipyridamole (Persantine) on the thrombocyte count and bleeding tendency in connection with open-heart surgery and perfusion was studied in 22 patients. A control series of 21 patients undergoing open-heart surgery was available. The treatment group received dipyridamole, 0.5 mg. per kilogram of body weight, in the beginning of cardiopulmonary bypass into the heart-lung machine and thereafter 10 mg. intravenously three times daily for 2 days. From the third day dipyridamole was administered by mouth, 75 mg. three times a day, until the patient was discharged from hospital. We found that dipyridamole had the effect of maintaining the thrombocyte count during cardiopulmonary bypass and the first and second postoperative days. Thereafter no significant difference was seen between the dipyridamole and control groups. The use of dipyridamole did not increase the postoperative hemorrhagic tendency. There were no significant differences in per- and postoperative blood loss and in bleeding and activated partial thromboplastin times between the groups.