History of acute myocardial infarction in patients with acute coronary syndrome: population characterization and impact on prognosis

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Patients with a history of Acute Myocardial Infarction (AMI) continue to be underrepresented in large studies on Acute Coronary Syndromes (ACS). Purpose To characterize patients with ACS and previous AMI and to evaluate their impact on the therapeutic approach, complications and in-hospital mortality. Methods We studied 722 patients admitted to a Cardiac Intensive Care Unit with a diagnosis of ACS. We considered 2 groups: patients with previous AMI and patients without previous AMI. Age, gender, personal history, clinical and electrocardiographic presentation of the ACS, treatment at admission, left ventricular ejection fraction (EF), coronary angiography and angioplasty were recorded. The following in-hospital complications were defined: heart failure, cardiogenic shock, re-infarction, mechanical complications, stroke and major hemorrhage. In-hospital mortality was compared between both groups. Results Patients with previous AMI constituted 26.8% (194 patients) of the population studied. These had a higher prevalence of arterial hypertension (92.8% vs 71.2%; p<0.001), diabetes (47.9% vs 30.4%, p<0.001), dyslipidemia (73.6% vs 49 .2%, p<0.001), previous angioplasty (62.1% vs 0.0%; p<0.001), heart failure (14.0% vs 4.7%, p<0.001), arterial disease (13.5% vs 3.6%, p<0.001), chronic renal failure (18.7% vs 9.6%, p=0.009) and previous bleeding (5.3% vs 1.3 %, p=0.002). The D with previous AMI presented more frequently with AMI without ST elevation (62.4% vs 40.7%; p<0.001) and Unstable Angina (10.3% vs 5.3%, p=0.02 ) and less with ST-elevation AMI (22.2% vs 47.3%, p<0.001). At admission, patients with previous AMI received less therapy with unfractionated heparin (20.6% vs 30.7%; p=0.007) and more therapy with angiotensin-2 antagonists (6.2% vs 2.3% , p=0.009), nitrates (62.9% vs 49.2%, p=0.001), ivabradine (5.2% vs 1.7%, p=0.01) and diuretics (34.5% vs 22 .3%, p=0.009). The coronary angiography rate was similar between the groups, however patients with previous AMI underwent more coronary angiography via the femoral route (36.9% vs 15.7%, p<0.0001) and fewer angioplasties (58.5% vs 69 .5%, p=0.006). EF was slightly lower in patients with previous AMI (45.7 ± 9.3% vs 48.3 ± 10.4%, p=0.04). However, there were no differences in the presence of any of the complications considered, as well as in in-hospital mortality. Conclusion Patients with previous AMI have a higher prevalence of co-morbidities and a higher prevalence of AMI without ST elevation and Unstable Angina. The presence of previous AMI was not per se a predictor of in-hospital complications or mortality.