Intracoronary administration of dipyridamole prior to percutaneous transluminal coronary angioplasty provides a protective effect exceeding that of ischemic preconditioning.

BACKGROUND

Ischemic preconditioning renders hearts more resistant to the deleterious consequences of ischemia. Adenosine is an important mediator in the induction and maintenance of ischemic preconditioning. Percutaneous transluminal coronary angioplasty (PTCA) allows the investigation of the consequences of ischemia in humans. The severity of myocardial ischemia decreases with subsequent balloon inflations during the course of PTCA.

OBJECTIVE

To compare the effect of intracoronary administration of dipyridamole with the effect of consecutive balloon inflations.

METHODS

We investigated 30 patients undergoing PTCA of the left anterior descending coronary artery in the setting of stable angina pectoris. Patients were randomly allocated to be administered either 0.5 mg/kg body weight dipyridamole intracoronarily or an equal amount of saline. Patients administered saline served as a control group. All patients were subjected to three consecutive balloon inflations. Severity of myocardial ischemia was assessed in terms of severity of chest pain, electrocardiographic signs of ischemia, and duration of balloon inflation tolerated.

RESULTS

Patients administered dipyridamole intracoronarily tolerated significantly longer durations of balloon inflation than did patients in the control group. Severity of anginal pain and extent of electrocardiographic signs of ischemia were significantly lower after intracoronary administration of dipyridamole. The reductions in anginal pain and ST-segment shift caused by intracoronary administration of dipyridamole during the first balloon inflation were even more pronounced than the protection that was afforded by the third balloon inflation for patients in the control group.

CONCLUSIONS

Intracoronary administration of dipyridamole prior to PTCA is associated with a significant gain in tolerance of ischemia. The protection afforded by intracoronary administration of dipyridamole is even more pronounced than the effect of ischemic preconditioning.