Abordagem Invasiva versus Conservadora nas Síndromes Coronárias Agudas sem Supradesnivelamento do Segmento ST – Contributo para o Conhecimento e Avaliação da Realidade Nacional

BACKGROUND: In addition to medical therapy, revascularization plays an important role in determining prognosis in the acute setting of unstable angina (UA) or non-ST elevation myocardial infarction (NSTEMI). OBJECTIVE: To compare in-hospital and medium-term outcome of an invasive versus a conservative strategy in the setting of UA/ NSTEMI. METHODS: We carried out a prospective study of 802 consecutive patients admitted to a single coronary unit between May 2004 and December 2006 with UA/NSTEMI. Patients were divided into two groups: A (n=418)--invasive strategy; B (n=384)--conservative strategy. All-cause mortality and major adverse cardiovascular events (MACE) were assessed at one year. RESULTS: Group B patients were older (73.0 [29-93] vs. 64.0 [27-86] years, p < 0.001), more frequently female and diabetic (35.9 vs. 26.0%, p = 0.002), and were more likely to have a history of myocardial infarction and heart failure. They also presented with worse renal function, lower hemoglobin levels and lower left ventricular ejection fraction (53.0 [45-59] vs. 57.0% [50-60]%, p < 0.001). In hospital mortality was significantly higher for this group (5.7 vs. 1.9%, p = 0.004). Group A had more smokers, more frequent history of percutaneous coronary intervention, higher total and LDL cholesterol, lower Killip class on admission and lower TIMI scores. They were more frequently treated with anti-platelet therapy and at discharge were more often under beta-blocker and dual anti-platelet therapy. Female gender (adjusted OR 0.46; 95% CI 0.27-0.78) and older age (adjusted OR 0.55; 95% CI 0.31-0.99), were independent predictors for a conservative strategy during hospital stay. One-year survival was higher for the invasive strategy patients (95.9% vs. 86.2%, log rank p < 0.001), as was one-year MACE-free survival (88.3% vs. 75.7%, log rank p < 0.001). According to two multivariate Cox regression analyses, opting for an invasive strategy during hospital stay conferred a 57% reduction in relative risk of death (HR 0.43; 95% CI 0.20-0.94), and a 56% reduction in relative risk of MACE (HR 0.44; 95% CI 0.26-0.77) at one year. CONCLUSIONS: Despite some imbalances between the groups, in our population an invasive strategy during hospital stay independently predicted a favorable one-year outcome.