[Protection and "preconditioning" of the human heart during percutaneous transluminal coronary angioplasty (PTCA) by intracoronary dipyridamole administration]

Abstract

Background and aim: A brief episode of ischemia followed by reperfusion termed "ischemic preconditioning" has been identified as a mechanism rendering the myocardium more resistant to ischemia. Recently adenosine has been identified as an important mediator of ischemic preconditioning. Dipyridamole represents an important drug interfering with myocardial adenosine metabolism by inhibiting its degradation. The aim of this study was to investigate the effect of an intracoronary dipyridamole infusion on the extent and tolerance of myocardial ischemia during percutaneous transluminal coronary angioplasty (PTCA).

Patients and methods: In the first study group 46 patients undergoing coronary angioplasty were randomised to receive dipyridamole or conventional treatment before PTCA. In the second study group 11 patients were investigated, receiving PTCA of restenosis following PTCA carried out 6 months earlier.

Results: In the first group as a striking result patients receiving pretreatment with dipyridamole tolerated longer times of balloon inflations (155.3 +/- 68.9 vs. 93.1 +/- 24.7 s), expressed lower severity of cardiac pain, demonstrated less pronounced ST-segment shifts on the surface ECG and showed a lower incidence of arrhythmias. In the second group the first dilatation had been performed conventionally, while pretreatment with dipyridamole had been performed prior to the dilatation of restenosis. Similar to the findings in the first patient group pretreatment with dipyridamole resulted in enhancement of balloon inflation times, regression in cardiac pain and lower extent of ST-segment shift and incidence of arrhythmias. In both study groups intracoronary application of dipyridamole showed no significant impact on heart rate and arterial blood pressure.

Conclusion: Summarising our results indicate, that intracoronary application of dipyridamole renders the heart more resistant to ischemia.