Left ventricular function in acute myocardial infarction treated with thrombolysis followed by early versus late invasive strategy

Abstract

Background: Thrombolysis remains the treatment of choice in acute ST-segment elevation myocardial infarction (STEMI) when primary percutaneous coronary intervention (PCI) cannot be performed within 90 to 120 minutes. The optimal treatment after thrombolysis is still debated, but several studies have shown improved clinical outcomes with early transfer for PCI. The aim of this study was to investigate whether an early invasive strategy after thrombolysis preserved left ventricular function better than a late invasive strategy.

Methods: This was a substudy of the NORwegian study on DIstrict treatment of ST-Elevation Myocardial Infarction. Patients with STEMI of <6 hours of duration and >90 minutes of expected transfer delays to PCI were treated with aspirin, tenecteplase, enoxaparin, and clopidogrel and randomized to early or late invasive strategy (N = 266). Left ventricular volumes and ejection fraction were assessed by single-photon emission computed tomography, echocardiography, and magnetic resonance imaging 3 months after the index infarction.

Results: Noninvasive imaging was completed in 241 patients (91%). Median end-diastolic and end-systolic volumes after 3 months did not differ between groups. Median ejection fraction was well preserved and also without differences: 63% (interquartile range 51-70) in the early invasive versus 65% (interquartile range 55-71) in the late invasive group when assessed by single-photon emission computed tomography (P = .30), 55% versus 55% when assessed by echocardiography (P = .88), and 57% versus 57% when assessed by magnetic resonance imaging (P = .99).

Conclusion: In this group of STEMI patients treated with thrombolysis, no difference in left ventricular function after 3 months was found between patients treated with early versus late invasive strategy.

Trial registration: ClinicalTrials.gov NCT00161005.