RECOVERY OF MYOCARDIAL PERFUSION IN ACUTE MYOCARDIAL-INFARCTION AFTERSUCCESSFUL BALLOON ANGIOPLASTY AND STENT PLACEMENT IN THE INFARCT-RELATED CORONARY-ARTERY

Objectives. This study sought to investigate changes in myocardial per fusion after direct percutaneous transluminal coronary angioplasty (PT CA) in acute myocardial infarction (MI). Background. After initially s uccessful recanalization of the infarct-related artery, coronary-perfu sion may deteriorate as a result of reocclusion, distal embolization o f platelet aggregates formed at the dilated plaque or microvascular re perfusion injury. This change could offset the benefit from early inte rvention. Methods. The study included 19 patients in whom the infarct- related artery was successfully recanalized by PTCA with Palmaz-Schatz stent placement within 24 h after the onset of pain. Basal and papave rine-induced coronary blood flow mere assessed by Doppler flow velocit y measurements and quantitative coronary angiography, In addition, bas al and adenosine-induced myocardial blood how mere measured by nitroge n-13 ammonia positron emission tomography (PET). Results. Immediately after completion of the intervention, the average coronary flow reserv e (CR) in the recanalized vessel was 1.56 +/- 0.51; it increased to 2. 04 +/- 0.65 at 1 h (p = 0.013) and to 2.66 +/- 0.72 at 2 weeks after r eperfusion (p = 0.008, n = 16). PET studies in 12 patients revealed th at perfusion defect size and CR in the infarct region (2.19 +/- 0.89 v s. 2.33 +/- 0.86) did not change significantly between day 2 after rec analization and 2 weeks. However, we found significant (p < 0.03) incr eases in basal (by 26%) and adenosine-induced (by 40%) blood flow in t he infarct region. Conclusions. Despite the persistence of a perfusion defect after successful recanalization of the occluded artery in acut e MI, CR of the infarct region improves in most patients within 1 h an d further improves within 2 weeks. (C) 1997 by the American College of Cardiology.