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The accuracy of tissue Doppler parameters of right ventricular function including Isovolumic relaxation time (IVRT) and Isovolumic contraction time (IVCT) have not been validated sufficiently in pulmonary hypertensive patients (pts).
To assess the ability of tissue Doppler imaging (TDI) - as a noninvasive method- to predict pulmonary artery pressure and to determine the possibility of assessment of severity of pulmonary hypertension.
Patients and Methods
The study population comprised three parallel groups of consecutive patients. The study groups were: Group I (31 control subjects) in which conventional Doppler and TDI-derived echocardiographic variables were measured from lateral tricuspid annulus and compared with Group II (30 pts with pulmonary hypertension and normal left side structure and function) and group III (30 pts with pulmonary hypertension and dilated cardiomyopathy).
In group I the median age of the pts was 40.4 years, 68% of them were males, in group II the median age of the pts was 35.5 years, 76.7% of them were females while in group III the median age of the pts was 33.5 years, 80% of them were males. The estimation of PASP was derived from tricuspid regurgitation velocity according to the Bernoulli equation. The measurement of IVRT was calculated using pulsed tissue Doppler. In group II and in group I (p, 0.0001), the average IVRT was 81.00±6.3 ms [95% confidence interval (CI):65–96] and 32.3±7.05 ms (95% CI: 20–50), respectively. We found a strong correlation between IVRT and systolic pulmonary pressure in group II (r=0.57, p, 0.0001) and a cut-off of 57.5 ms showed a sensitivity and specificity of 100% and 97%, respectively, for the prediction of elevated PASP. In group II and in the group I (p, 0.0001), the average IVCT was 34.2±4.8 ms [95% confidence interval (CI):25–45] and 61.5±9.7 ms (95% CI: 45–75), respectively. We found a strong inverse correlation between IVCT and systolic pulmonary pressure in the PH group (r =-0.38, p, 0.0001) and a cut-off of 35.5ms showed a sensitivity and specificity of 60% and 63%, respectively, for the prediction of elevated PASP.
The measurement of IVRT and IVCT by TDI is a simple and reproducible method that correlates well with PASP. It is, therefore, parameters to consider in the echocardiographic assessment of pts with PH, and may be particularly important when the tricuspid Doppler signal is poor.