DEPT. OF ECHOCARDIOGRAPHY, SHAHEED RAJAEE CARDIOVASCULAR MEDICAL CENTER, MELLAT PARK, VALI ASR AVENUE, TEHRAN, IRAN
Background: The assessment of pulmonary artery pressure is, important in clinical management and prognostic evaluation of patients with cardiovascular and pulmonary disease. Today, the accurate measurement of pulmonary artery pressure requires the use of cardiac catheterization. However, reliable non-invasive evaluation of pulmonary pressure still presents a problem. The purpose of the present study was to determine whether the isovolumic relaxation time (IVRT) obtained by pulsed Doppler tissue imaging from tricuspid annular motion could be used as an index of pulmonary pressure in patients with valvular, coronary and congenital heart disease.
Methods: Simultaneous tissue Doppler echocardiography and right heart catheterization were performed in 80 patients (mean age 46 years, 36 male) with valvular heart disease (n=59), coronary heart disease (n=20) and congenital heart disease (n=15). The patients were divided into three groups: group I: pulmonary systolic pressure (post-LV injection phase) in 25-40 mmHg range (n=28); group II: 41-60 mmHg range (n=37); and group III: 61-100 mmHg range (n=15). The isovolumic relaxation time (IVRT) was measured from the tricuspid annulus in apical 4C view at the junction of the right ventricular free wall and the anterior leaflet of the tricuspid valve by tissue Doppler imaging. Cardiac catheterization and pulmonary artery systolic-diastolic pressures (pre-LV injection and post-LV injection phase) were measured. The IVRT was compared with pulmonary artery systolic- diastolic pressures by means of linear regression analysis.
Results: There was a significant correlation in all the groups between the IVRT and the sum of pulmonary artery systolic-diastolic pressures in post-LV injection phase (r= 0.99, P<0.0001). The linear regression equation is:
IVRT= [(PA systolic pressure in post-LV injection phase) + (PA diastolic pressure in post-LV injection phase)]±5.
Some factors such as RV function, underlying disease (valvular, coronary, congenital heart disease), age and sex have no effect on the calculated formula. The IVRT value was compared in the three groups: group I: 51.79 ms±8.35 STD; group II: 74.19 ms±10.51 STD; and group III: 108.27ms±16.43 STD. The IVRT values between the three groups had significant differences (P<0.001). An IVRT ³77 ms predicted pulmonary artery systolic pressure (Post LV injection phase) ³50 mmHg with a sensitivity of 93% and a specificity of 80%.
Conclusion: We conclude that the evaluation of the isovolumic relaxation time from the tricuspid annulus by Doppler tissue imaging provides a simple, rapid and non- invasive tool for estimating pulmonary pressure in patients with valvular, coronary and congenital heart disease.