Estimation of Elevated Systolic Pulmonary Artery Pressure Using Right Ventricular Isovolumic Relaxation Time

Echocardiographic estimation of pulmonary hypertension (PH) in absence of tricuspid regurgitation (TR) remains a challenge. Isovolumic relaxation time (IVRT) measured by Doppler tissue imaging (DTI) can be a useful method to estimate PH. This study was designed to evaluate the feasibility and accuracy of the right ventricle (RV) IVRT for predicting PH. We conducted an analytical cross-sectional study in 90 consecutive patients suspected or known to have pulmonary hypertension (PH). sPAP was assessed using TR jet velocity using a Bernoulli’s equation. RV IVRT was calculated using tissue Doppler imaging. Out of the 90 consecutive patients [49 (54.4%) were female, mean age was 48 +/- 14 years and mean systolic pulmonary aretry pressure (sPAP) was 68.25+/- 29.15 mmHg. Mean RV IVRT was 67.29 ± 22.2 msec. We found a strong correlation between IVRT and systolic pulmonary pressure (r = 0.69, P < 0.0001) and a cutoff of 43 ms showed a sensitivity and specificity of 89% and 93%, respectively, for the prediction of elevated sPAP (≥39 mm Hg). However, this correlation reduces in the presence of RV dysfunction and elevated mean RA pressure. The calculation of IVRT by DTI is a simple and feasible method. It correlates well with sPAP. It is a useful echocardiographic parameter as a screening in patients at risk for PH, monitoring the disease progression and the effect of the treatment for PH, especially in patients with absent TR.