VALIDATION OF NEW PULSED DOPPLER ECHOCARDIOGRAPHIC TECHNIQUES FOR ASSESSMENT OF PULMONARY HEMODYNAMICS

In preparation for a vasodilator study on chronic obstructive pulmonar y disease (COPD), we investigated the reliability of recently describe d pulsed Doppler techniques for estimating pulmonary artery pressure ( PAP) and cardiac output (CO). Our aims were to determine the following : (1) the imaging success rate for pulsed Doppler measurements; (2) th e repeatability of the measurements, and interobserver and intraobserv er variability; and (3) the accuracy of Doppler compared with catheter measurements. Doppler studies were attempted in 81 patients (cardiac diseases [23], COPD [22], sleep apnea [32], and normal subjects [4]). Suitable images were obtained in 68 subjects (84 percent) and in 76 su bjects (94 percent) for PAP and CO estimations, respectively. The lowe st imaging success rates were in COPD patients (68 percent for PAP and 86 percent for CO estimation). Repeatability of the techniques was as sessed in four cardiac patients and three healthy volunteers by perfor ming four replicate studies in each subject over 1 h. Intrasubject coe fficient of variation was <10 percent for PAP and <5 percent for CO. T he intraobserver variability for Doppler estimation of systolic and me an PAP was 5.5 percent and 5.8 percent, respectively. The correspondin g values for interobserver variability were 6.7 percent and 6.2 percen t. Intraobserver and interobserver variability for ''nongeometric'' me thod of estimating Co was 5.1 percent and 5.9 percent, respectively. A greement was good between catheter-measured and Doppler-estimated PAP in the 27 patients tested (cardiac [19] and COPD [81) for both mean an d systolic pressures (r = 0.96 and r = 0.97, respectively). The correl ations between thermodilution and Doppler estimations of CO in eight C OPD patients were 0.77 (''geometric'' technique) and 0.97 (''nongeomet ric'' technique). We conclude that pulsed Doppler techniques can be us ed to obtain accurate and reproducible quantitative information on pul monary hemodynamics in a wide range of patients. Suitable Doppler imag es can be obtained in more than two thirds of COPD patients.