Predicting Heart Failure Symptoms by Plasma N-terminal Pro B-Type Natriuretic Peptide for Patients with Chronic Aortic Regurgitation and Preserved Left Ventricular Function

Background: Plasma N-terminal pro B-type natriuretic peptide (NT-proBNP) secretion is stimulated by increased ventricular wall and volume expansion. In the present study, we hypothesized the concentrations of NT-proBNP would be increased proportionately with increasing aortic regurgitation (AR) severity due to volume overload. Furthermore, we wanted to explore the value of NT-proBNP as a marker for AR patients with symptoms of congestive heart failure. Method: Eighty-two patients were divided into 3 groups as determinated by the severity of AR and symptoms of congestive heart failure; they included: Non-significant AR (n=30)-the ratio of regurgitant jet width to left ventricular outflow tract diameter (LVOTD)＜45% and New York Heart Association (NYHA) functional class I; Asymptomatic significant AR (n=26)-the ratio of regurgitant jet width to LVOTD≥45% and NYHA functional class Ⅰ; Symptomatic significant AR (n=26)-the ratio of regurgitant jet width to LVOTD≥45% and NYHA functional class Ⅱ, Ⅲ, or Ⅳ.An immunoassay method was used for the quantitative determination of NT-proBNP. Result: The level of NT-proBNP was significantly higher in patients with symptomatic significant AR (1534.1±2106.7 pg/ml) than the value in the non-significant AR group (122.6±125.6 pg/ml) and the asymptomatic significant group (299.4±247.7 pg/ml) (p＜0.001 and p=0.001, respectively). An NT-proBNP level≥210 pg/ml was associated with the highest combination of sensitivity (78%) and specificity (68%) for the prediction of significant symptomatic AR. The possibility of missing symptomatic significant AR was low with NT-proBNP level＜110 pg/ml. The possibility of diagnosing symptomatic significant AR was extremely high with NT-proBNP level≥860 pg/ml. Conclusion: NT-proBNP level was strongly related to symptoms of CHF and could be used for predicting symptoms of CHF in patients with significant chronic AR.