Improving myocardial salvage in late presentation acute ST-elevation myocardial infarction with proximal embolic protection.

Background: Late-presenting ST-elevation myocardial infarction (STEMI) patients possess larger, more organized coronary thrombus leading to greater ventricular remodeling and arrhythmia despite angioplasty and pharmacological therapies. We hypothesized that myocardial injury would be reduced in late STEMI by proximal embolic protection (PEP).
Methods: 31 patients with first STEMI 12-24 hr after pain onset and TIMI 0-1 flow were treated with or without PEP (cohort design matched for age, gender, and infarct-related artery). Contrast-enhanced magnetic resonance determined myocardial function, area at risk, necrosis, salvaged myocardium, and arrythmogenic peri-infarct region. Clinical follow-up was performed.
Results: Pain to balloon time was 18 hr (95% CI 15.5-21.2 h), and Q waves were present in 87%. Angioplasty was performed with PEP in 15 and without in 16. Left ventricular (LV) volumes and ejection fraction were similar (EF 46.9% vs. 49.0% without PEP, P = 0.9). Although myocardial necrosis was similar (32.5 vs. 37.3% of LV, P = 0.3), PEP improved microvascular obstruction (8.7 vs. 11.2% of LV, P = 0.02) salvaged myocardium (39.6% vs. 29.6% of area at risk, P = 0.001), and the peri-infarct region (20.9 vs. 29.6% of infarct, P < 0.0001). On multivariate analysis, the use of PEP was an independent predictor of decreased arrythmogenic peri-infarct region and greater myocardial salvage.
Conclusion: In this pilot study, PEP improved myocardial salvage and the arrythmogenic peri-infarct region in late-presentation STEMI. Randomized trials are required to assess the clinical impact of improving salvaged myocardium and the peri-infarct region with PEP.
(© 2010 Wiley-Liss, Inc.)