Does coronary angioplasty after timely thrombolysis improve microvascular perfusion and left ventricular function after acute myocardial infarction?

BACKGROUND: Recent data show that percutaneous coronary intervention (PCI) in patients with stable postthrombolytic ST-segment elevation myocardial infarction (STEMI) is better than no PCI or ischemia-guided PCI. These results still have to find a pathophysiologic explanation. We hypothesized that complete mechanical recanalization of infarct-related artery improves clinical benefits of thrombolysis as a result of more preserved and better perfused coronary microcirculation. To test this hypothesis, we studied a selected STEMI population presenting very early after symptom onset in whom successful infarct-related artery reperfusion was obtained by thrombolysis followed or not by elective PCI within 24 hours, and we compared these 2 groups with those underwent primary PCI. METHODS: This study analyzed 96 patients with STEMI randomized within 3 hours from symptom onset to primary PCI (group A, n = 36), tenecteplase followed within 24 hours by PCI (group B, n = 30), or to tenecteplase alone (group C, n = 30). Microvascular perfusion was assessed by myocardial contrast echocardiography. Regional contrast score, endocardial length and area of contrast defect on day 2 (T1) and at predischarge (T2), left ventricular end-diastolic volume, regional wall motion score, extent of wall motion abnormalities, and ejection fraction at T1, T2, and at 3 months' follow-up were calculated. RESULTS: Baseline clinical and angiographic characteristics were not statistically different between groups. The extent of microvascular damage and of myocardial salvage was similar in primary PCI-treated or in invasively treated patients after lytic administration. Conversely, group C patients, although treated very early with fibrinolytic therapy, showed higher extent of microvascular damage and infarct size and a more depressed left ventricular function after reperfusion and at follow-up. CONCLUSIONS: Our data suggest that early PCI after lysis is more effective in preserving myocardial perfusion and function than lysis alone and may be a helpful alternative when primary PCI is not available.