Plasma level of NT-proBNP in assessment of functional capacity and prognosis in patients with heart failure

ABSTRACTPlasma Level of NT-proBNP in Assessment of Functional Capacity and Prognosis inPatients with Heart FailureNew York Heart Association (NYHA) classification is frequently used for theassessment of functional capacity in heart failure patients. However, the classification is asubjective method and may change according to the loading conditions. We investigated therelation between the levels of NT-proBNP at rest and after exercise and functional capacityand also one year mortality and/or morbidity.One-hundred heart failure patients (88 male, 12 female and mean age: 53.6 ± 8.9years) and 20 healthy subjects (17 male, 3 female and mean age: 51.5 ± 4.8 years) wereenrolled the study. All subjects underwent echocardiography and exercise test. The levels ofNT-proBNP were measured at rest and after exercise. The patients were followed up 420 ± 45days.The level of NT-proBNP at rest and left atrium diastolic dimension were the mostimportant parameters in predicting functional capacity (p<0.001 and p=0.0001, respectively).The level of NT-proBNP at rest was an independent predictor of the functional capacity < 5METS (p=0.002) and with a cut-off value 860 pg/ml the sensitivity and specificity were86.7% and 80.0%, respectively. The absolute NT-proBNP which increased with exercise wasfound to be the only independent predictor of mortality in patients with NYHA class I-III(p=0.035). However, only left ventricular ejection fraction and the level of NT-proBNP at restwere the independent predictors of mortality in all patients (p=0.001 and p=0.004,respectively). The independent predictors of mortality or morbidity, as the end point of thestudy, were the level of NT-proBNP at rest, left ventricular mass index and resting heart rate(p=0.006, p=0.020 and p=0.006, respectively). The one year survival rates were 50% and 96%in patients with plasma level of NT-proBNP >1570 and those with ≤1569 pg/ml, respectively.In conclusion, NT-proBNP is an easy and reliable parameter in predicting functionalcapacity and mortality and/or morbidity in patients with heart failure.Keywords: NT-proBNP, Heart failure, Functional capacity, Mortality and/ormorbidityX