AUGMENTATION OF INTERCORONARY ANASTOMOSIS BY LONG-TERM ADMINISTRATION OF A VASODILATOR DRUG, DIPYRIDAMOLE (PERSANTIN).

A study was carried out to assess the ability of dipyridamole to promote intercoronary anastomotic channels in the dog. Nineteen normal dogs received 150-300 mg. dipyridamole daily for 73 to 162 days and were compared with 18 control animals. Employing pentobarbital sodium (Nembutal) anesthesia and positive pressure ventilation, the chest was opened and the circumflex coronary artery was tied and cannulated distal to the tie. The average retrograde flow in the treated group was significantly higher than that in the control group (p < 0.02). Acute administration of dipyridamole intravenously produced comparable reduction of blood pressure and retrograde flow in both groups of animals. Thus the long-term administration of dipyridamole appears capable of promoting the growth of intercoronary anastomotic pathways in some animals even in the absence of any known ischemic stimulus. This would appear to be the result of sustained vasodilator action.