RESUMO
We performed treadmill exercise magnetic resonance imaging in 27 patients with exertional chest pain who were referred for contrast coronary angiography to determine the feasibility of this method to identify severe coronary artery stenoses. The sensitivity and specificity for detecting >70% coronary artery luminal diameter narrowings on contrast coronary angiography were 79% and 85%, respectively.
Assuntos
Estenose Coronária/diagnóstico , Teste de Esforço/métodos , Imageamento por Ressonância Magnética/métodos , Adenosina , Idoso , Cardiotônicos , Angiografia Coronária/métodos , Estenose Coronária/classificação , Estenose Coronária/complicações , Dobutamina , Eletrocardiografia , Teste de Esforço/instrumentação , Teste de Esforço/normas , Estudos de Viabilidade , Feminino , Humanos , Imageamento por Ressonância Magnética/instrumentação , Imageamento por Ressonância Magnética/normas , Masculino , Pessoa de Meia-Idade , Sensibilidade e Especificidade , Índice de Gravidade de Doença , Método Simples-Cego , Fatores de Tempo , Vasodilatadores , Disfunção Ventricular Esquerda/etiologia , Disfunção Ventricular Esquerda/fisiopatologiaRESUMO
BACKGROUND: We postulated that antibodies to platelet factor 4/heparin complex might contribute to recurrent ischemic events in patients with acute coronary syndrome. METHODS AND RESULTS: We analyzed serum from patients enrolled in the placebo/unfractionated heparin arm of the GUSTO IV-ACS trial who had high likelihood of prior heparin exposure. We selected 109 patients without thrombocytopenia with the 30-day primary end point (death, myocardial infarction [MI], or revascularization) and 109 age-, gender-, and race-matched controls who did not achieve the primary end point. An ELISA for anti-platelet factor 4/heparin antibodies was performed using 48-hour serum samples. The analyses were done by blinded investigators, and the results were correlated with clinical outcomes. Twenty-three of 218 patients (10.6%) had anti-PF4/heparin antibodies. Patients with anti-PF4/heparin antibodies were more likely to have death or MI (30.4% versus 11.3%, P=0.011) or MI (21.7% versus 6.2%, P=0.008) than patients who were negative for the antibody. After multiple logistic regression analysis, anti-PF4/heparin antibodies remained a predictor of 30-day death or MI (odds ratio, 4.0; 95% CI, 1.4 to 11.3; P=0.0093) and MI (odds ratio, 4.6; 95% CI, 1.4 to 15.0; P=0.0108). The antibody was not associated with the composite end point (death, MI, or revascularization) or with death or revascularization alone. CONCLUSIONS: Antibodies to the platelet factor 4/heparin complex are a novel, independent predictor of myocardial infarction at 30 days in patients presenting with acute coronary ischemic syndromes. This finding may explain the previous association between thrombocytopenia and adverse events in patients with acute coronary syndrome and may have important implications for the choice of anticoagulant regimens.
