The Use of Transthoracic Echocardiogram to Quantify Pulmonary Vascular Resistance in Patients with Systemic Sclerosis.

Abstract

To explore the accuracy of tricuspid regurgitation velocity (TRV) to right ventricular outflow tract time-velocity integral (TVI_RVOT) ratio by Doppler to determine pulmonary vascular resistance (PVR) in patients with systemic sclerosis (SSc). Thirty-five consecutive adult patients with SSc, fulfilling the 2013 European League Against Rheumatism/American College of Rheumatology classification criteria, with sinus rhythm referred for right heart catheterization (RHC), were retrospectively included. All patients underwent a transthoracic echocardiogram (TTE) performed within 24 h of RHC. Patients with SSc were recruited regardless of disease activity, cardiac symptoms, and treatment regimen. Doppler measurements were compared to RHC measurements. A linear regression equation was generated to predict PVR by echocardiogram based on the TRV/TVI_RVOT ratio. The accuracy of Doppler measurements for predicting PVR > 3 Wood units was assessed by computing the areas under the receiver-operating characteristic curves. There were 20 (57%) females in the study. The mean age was 65 ± 12 years. Mean and systolic pulmonary arterial pressures were 31 ± 8 and 53 ± 15 mmHg, respectively. There was a good correlation between TRV/TVI_RVOT ratio assessed by Doppler and PVR measured by RHC (R = 0.743, p < 0.001). The equation generated by this analysis was the following: PVR by Doppler = 11.3 × (TRV/TVI_RVOT) + 1.7. A cutoff value of 0.21 for TRV/TVI_RVOT ratio provided the best sensitivity (86%) and specificity (86%) to determine PVR > 3 Wood units. Our study suggests that TTE using Doppler could be a useful and noninvasive tool for estimating PVR in patients with SSc.