Page 82 - The role of advanced echocardiography in patients with ischemic heart disease - Rachid Abou

Chapter four. Left ventricular recovery after STEMI
DISCUSSION
The prevalence of severe LV systolic dysfunction (LVEF ≤40%) after STEMI has reduced significantly with the systematic use of primary PCI.8,9,14,15,16 The prevalence of severe LV systolic dysfunction in large series of patients with STEMI treated with primary PCI is approximately 20%.17,18 In a study including 216 patients with STEMI treated with primary PCI, Stolfo et al reported a prevalence of LVEF ≤40% of 19%.17 In addition, in a multicenter study of 3,798 STEMI patients treated with primary PCI, the prevalence of an LVEF ≤35% was 20%.18 In the present study, the prevalence of LVEF ≤40% was 13%; this lower prevalence of LV systolic dysfunction compared with previous studies can be explained by different populations: the aforementioned studies included older patients, with higher prevalence of comorbidities and previous myocardial infarction as well as less strict use of cardiovascular medication recommended in current guidelines.8,9 Furthermore, ischemic preconditioning before PCI, presence or absence of collateral flow and onset of reperfusion time are important factors influencing infarct size that have not been taken into consideration systematically in all studies. LV functional recovery and remodeling is a continuous process influenced by several factors including location of the culprit lesion and area at risk, timing of revascularization, loading conditions and medication.19
Data on changes in LVEF after STEMI treated with primary PCI are scarce. Stolfo et al evaluated 154 STEMI patients treated with primary PCI and demonstrated that 72% of patients had LVEF >35% after 3 months follow-up.17 Similarly, Søholm et al reported that 64% of 138 STEMI patients treated with primary PCI had LVEF >35% at 3 months follow-up.20 The use of guideline-based therapy to prevent LV remodeling in those studies was rather low. In the study by Stolfo et al,17 78% of patients were on ACEi or ARB-II and only 75% received beta-blockers. In the study by Søholm et al,20 90% of patients were treated with ACEi or ARB-II, 2% were on calcium-antagonists and 48% received beta-blockers, while use of aldosterone antagonists was not reported. Conversely, in the present study patients were treated systematically according to guidelines, achieving ≥94% use of ACEi, ARB-II and beta-blockers. This may have resulted in larger percentage of patients with an improvement in LVEF >40% at 6 months follow-up as compared to previous studies.17,20 In addition, in previous studies there was probably less emphasis on the importance of adherence to guideline-based therapy.17,20
Several factors have been associated with LVEF improvement in STEMI patients after primary PCI. The peak troponin level is an adequate reflector of infarct size as assessed
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