Arquivos Brasileiros de Cardiologia (Sep 2006)
Estratificando o risco na angina instável com a ecocardiografia sob estresse com dobutamina Stratifying the risk in unstable angina with dobutamine stress echocardiography
Abstract
OBJETIVO: Avaliar a importância da ecocardiografia sob estresse pela dobutamina (EED) na estratificação de risco de pacientes com angina instável (AI) de baixo a moderado risco, quanto à capacidade de predizer os eventos clínicos combinados (morte de causa cardiovascular, infarto agudo do miocárdio (IAM), AI recorrente, necessidade de revascularização miocárdica) no seguimento de 6 meses. MÉTODOS: Estudo prospectivo, multicêntrico. Os pacientes incluídos estavam internados, assintomáticos havia 24 horas e a medicação em uso não era suspensa para a realização do exame. O EED era realizado preferencialmente até 72 horas da chegada ao hospital. RESULTADOS: Foram avaliados 95 pacientes consecutivos. O EED foi positivo para isquemia em 40 pacientes (42,1%) e em 55 (57,9%), foi negativo. Eventos ocorreram em 28 pacientes, 26 dos quais tinham o EED positivo para isquemia miocárdica. Os outros 67 pacientes não tiveram eventos; desses, 53 tinham o EED negativo. A sensibilidade, especificidade, acurácia, valor preditivo positivo e negativo do teste frente aos desfechos foram: 92,9%, 79,1%, 83,2%, 65% e 96,4%, respectivamente. Sobrevida livre de eventos após 6 meses para os pacientes com EED negativo foi de 96%, comparada com 35% nos que tiveram o EED positivo (pOBJECTIVE: To evaluate the role of dobutamine stress echocardiography (DSE) in the risk stratification of low to moderate risk unstable angina (UA) patients, to predict the combined clinical outcome of cardiovascular death, myocardial infarction (MI), recurrent UA and the need of revascularization procedures in a 6 month period. METHODS: Multicenter prospective study. Patients should be admitted to the hospital and asymptomatic in the last 24 hours. The exam was performed up to 72 hours from the hospital admission and no medication was stopped prior to the test. RESULTS: Ninety-five consecutive patients were evaluated by DSE. Forty patients (42,1%) had a positive ischemic test and fifty five (57,9%) had a negative one. Clinical events occurred in twenty eight patients, twenty six of whom had a positive test. The rest of the patients (67) did not have clinical events and fifty three of them, had a negative test. The sensibility, specificity, accuracy, positive predictive value and negative predictive value of the test related to the clinical events were: 92,9%, 79,1%, 83,2%, 65% and 96,4%, respectively. Event-free survival after 6 months for pacients with a negative DSE was 96% compared to 35% for those with a positive DSE (p<0,001). The UA classification, left ventricular ejection fraction, rest and peak wall motion score index, DSE result and history of previous MI were associated with the combined end point by univariate analysis. The test result was the only independent predictor of cardiac events by multivariate analysis (p<0.001). CONCLUSION: O DSE has shown an excellent negative predictive value allowing for early hospital discharge without further exams. The positive test result was the only independent predictor for adverse cardiac events.
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