Clinical utility of B-type natriuretic peptide for estimating left ventricular filling pressures in unselected elderly patients undergoing diagnostic coronary angiography.

BACKGROUND

B-type natriuretic peptide (BNP) and echocardiographic tissue Doppler indices (TDI) predict elevated filling pressures, but few data exist comparing these methods while adjusting for clinical variables. We hypothesized that BNP would provide incremental value for estimating left ventricular end-diastolic pressure (LVEDP).

METHODS

Clinical data, echocardiograms, and BNP levels were obtained in 182 geriatric patients undergoing diagnostic left-heart catheterization. Patients with severe valvular disease or acute myocardial infarction were excluded. LVEDP and standard echocardiographic measurements, including early (E) and late (A) mitral inflow velocities and early (Em) mitral annular velocities by TDI, were measured in blinded fashion.

RESULTS

Mean age was 71 years, 51% were female, and 19% were nonwhite. Univariate correlations with LVEDP (p < or = 0.05) included functional class, beta-blocker use, body-mass index (BMI), heart rate, blood urea nitrogen (BUN), hemoglobin, peak tricuspid regurgitation velocity, left atrial volume index, E/A ratio, deceleration time, septal E/Em ratio and BNP. Linear regression analysis revealed independent correlations of LVEDP with BMI (p = 0.002), BUN (p = 0.011), and E/A ratio (p < 0.001). After adjusting for these variables, BNP was an independent correlate of LVEDP (p = 0.001). Predictors of LVEDP > or = 20 mmHg by logistic regression included higher BMI (p = 0.002), lower heart rate (p = 0.042), and septal E/Em ratio < 15 (p = 0.023). BNP was an independent predictor of LVEDP > or = 20 mmHg after adjustment for these variables (p = 0.037, c-statistic 0.663).

CONCLUSIONS

Standard clinical variables offer only modest utility for predicting LV filling pressures. BNP provides incremental value for estimating LVEDP, and elevated BNP is an independent predictor of increased LVEDP among older patients undergoing diagnostic cardiac catheterization.