A simple method for noninvasive estimation of pulmonary capillary wedge pressure

Abstract

Background: Various Doppler echocardiographic indices were postulated for evaluation of cardiac performance, however, a reliable index for estimation of pulmonary capillary wedge pressure (PCWP) is unavailable. Objectives: We hypothesize the Doppler-derived variables in right ventricle provides a clinically reliable index to estimate PCWP and to assess the severity of congestive heart failure. Methods: Forty five patients with ischemic or idiopathic dilated cardiomyopathy underwent simultaneous BNP measurement, right-side catheterization and Doppler echocardiographic examination. We measured isovolumetric contraction time (ICT), ejection time (ET), isovolumetric relaxation time (IRT) in each ventricles (LV, RV) and analyzed the correlations with PCWP. Results: LVICT, LVET, LVIRT and RVIRT correlated poorly with PCWP. On the other hand, both RVICT and RVET had definite correlation (r = 0.75 and −0.71, respectively). And, we attempted to calculate a novel Doppler index defined as RVICT divided RVET (RVICT/ RVET) and found a good correlation with PCWP. (r = 0.83, p < 0.0001, PCWP = 4.15 + 50.5∗(RVICT/ RVET)). A RVICT/RVET cut off value of 0.20 had a sensitivity of 95.5% and a specificity of 91.3% to determine PCWP > 15mmHg. In addition, a RVICT/RVET value correlated well with plasma BNP level (r = 0.86, p < 0.001). Conclusions: Novel right ventricular Doppler index (RVICT/RVET) provides a simple and accurate means of estimating PCWP that is useful for assessment of the severity of congestive heart failure.