Noninvasive measurement of systemic vascular resistance using Doppler echocardiography

Background: Systemic vascular resistance (SVR) is an integral therapeutic component of patients with heart failure and shock. We hypothesized that the ratio of the peak mitral regurgitant velocity (MRV) (m/s) to left ventricular outflow time-velocity integral (TVILVOT) (cm) by Doppler would provide a noninvasive correlate of SVR. Methods: SVR was correlated to MRV/TVILVOT in 33 patients undergoing right heart catheterization. Receiver operating characteristic curves were generated to determine the best-balanced sensitivity and specificity to identify SVR > 14 Wood units (WU) and < 10 WU. Results: MRV/TVILVOT correlated well with SVR (r = 0.842, 95% confidence interval 0.7-0.92, P < .001, Y = 0.459 + 49.397*X). By receiver operating characteristics, MRV/TVILVOT > 0.27 had a 70% sensitivity and a 77% specificity to identify SVR > 14 W/U. MRV/TVILVOT < 0.2 had a 92% sensitivity and a 88% specificity to identify SVR < 10 WU. Conclusion: Doppler echocardiography provides a reliable noninvasive assessment of SVR.