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.