Arquivos Brasileiros de Cardiologia (Dec 2011)
Nível de NT-proBNP em pacientes com síndrome coronariana aguda sem supradesnivelamento do segmento ST NT-proBNP levels in patients with non-ST-segment elevation acute coronary syndrome
Abstract
FUNDAMENTO: A síndrome coronariana aguda (SCA) sem supradesnivelamento do segmento ST (SCASEST) está associada ao supradesnivelamento do peptídeo natriurético tipo B (BNP) e aos marcadores de necrose miocárdica, embora se desconheça a correlação dessa síndrome ao escore de trombólise no infarto do miocárdio (TIMI) e à função ventricular esquerda. OBJETIVO: Avaliar a correlação entre os níveis do fragmento N-terminal do peptídeo natriurético tipo B (NT-proBNP) e os marcadores de necrose miocárdica (creatinofosfoquinase fração músculo-cérebro CK-MB e troponina I), bem como entre o escore de risco TIMI e a fração de ejeção do ventrículo esquerdo (FEVE) nos pacientes com síndrome coronariana aguda sem supradesnivelamento do segmento ST. MÉTODOS: Oitenta e sete pacientes com síndrome coronariana aguda sem supradesnivelamento do segmento ST foram divididos em dois grupos: 37 (42,5%) com angina instável e 50 (57,5%) com infarto agudo do miocárdio sem supradesnivelamento do segmento ST (IAMSSST). RESULTADOS: A fração de ejeção do ventrículo esquerdo superior a 40% foi encontrada em 86,2% do total da amostra. Os níveis séricos de NT-proBNP foram maiores em pacientes com infarto do miocárdio sem supradesnivelamento do segmento ST, em comparação àqueles com angina instável (pBACKGROUND: Non-ST-segment elevation acute coronary syndrome is associated with elevation of brain natriuretic peptide and markers of myocardial necrosis, although its relationship with the TIMI score and left ventricular function are largely unknown. OBJECTIVE: To evaluate the correlation between plasma N-terminal pro-brain natriuretic peptide (NT-proBNP) and markers of myocardial necrosis [creatine phosphokinase muscle-brain fraction (CK-MB) and troponin I], TIMI risk score and left ventricular ejection fraction in patients with non-ST-segment elevation acute coronary syndrome. METHODS: Eighty-seven patients with non-ST-segment elevation acute coronary syndrome were divided into two groups: 37 (42.5%) with unstable angina and 50 (57.5%) with non-ST-segment elevation myocardial infarction. RESULTS: Left ventricular ejection fraction more than 40% was found in 86.2% of the total sample. Serum levels of NT-proBNP was higher in patients with non-ST elevation myocardial infarction than in those with unstable angina (p<0.001). Increased levels of NT-proBNP were associated with increases in troponin I (rs=0.425, p<0.001), peak CK-MB (rs=0.458, p<0.001) and low left ventricular ejection fraction (rs=-0.345, p=0.002); no correlation was found with the TIMI risk score (rs=0.082, p=0.44). Multivariate analysis revealed that left ventricular ejection fraction and troponin I levels were independently correlated with NT-proBNP levels (p=0.017 and p=0.002, respectively). CONCLUSION: Increased levels of NT-proBNP in patients with non-ST-segment elevation acute coronary syndrome are not related exclusively to low left ventricular ejection fraction, but can also be caused by the presence of myocardial ischemia and necrosis.
