Comparison of the discriminatory power of different echocardiographic methods in the assessment of the effect of pulmonary hypertension on right ventricular function

Pulmonary hypertension is a complex, progressive disorder which is characterized by an increase in pulmonary vascular resistance and which may lead to right heart failure, or even mortality. An echocardiographic study should be performed in every case with suspected PHT. Echocardiography is a readily available, cheap, and noninvasive method used for diagnosis of pulmonary hypertension. It is also helpful for evaluation of response to treatment and for follow-up. This study aimed to determine the best noninvasive echocardiographic parameter that indicates right ventricular dysfunction in the patients with pulmonary hypertension. In this study, we assessed right ventricular function by two-dimensional echocardiography, conventional Doppler, tissue Doppler imaging, Strain analysis, and three-dimensional echocardiography in subjects with previously diagnosed pulmonary hypertension or elevated pulmonary artery pressure in transthoracic echocardiography and in normal subjects. The patients with pulmonary hypertension were compared with the control group. Additionally, the subgroups of different pulmonary hypertension severity were compared with one another. Our study included a total of 40 pulmonary hypertensive patients, of whom 18 had a systolic pulmonary artery pressure below 50 mmHg and 22 patients over 50 mmHg. The control group included 21 healthy subjects. The mean age of the patient population was 64.7 ± 15.8 years and 30 (75%) of them were female. Except for a higher rate of smoking in the healthy subjects (p<0.05), both groups had similar basal clinical characteristics and laboratory results (p>0.05). A blood sample for brain natriuretic peptide measurement was also taken from each patient. The mean brain natriuretic peptide was 69.8 (10-793) pg/ml. The mean systolic pulmonary artery pressure measured with echocardiography was 56.4 ±16.8 mmHg. The pulmonary hypertension subgroup in which a right catheterization was performed had a significant correlation between echocardiographically and invasively measured systolic pulmonary artery pressures (p<0.05, r=0.883). Therefore, the correlation between echocardiographic parameters and noninvasively measured systolic pulmonary artery pressure was analyzed. There was a significant correlation between systolic pulmonary artery pressure and right atrial diameter (p<0.001, r=0.746), right ventricular diameter (p<0.001, r=0.643), right ventricular end-systolic area (p<0.001, r=0.637), right ventricular end-diastolic area (p<0.001, r=0.598), right atrial area (p<0.001, r=0.580), fractional area change (p<0.001, r=-0.563), and three-dimensional ejection fraction (p<0.001, r=0.544). However, pulmonary artery pressure had a little correlation with brain natriuretic peptide level. The multiple regression analysis showed that right ventricular diameter and three-dimensional ejection fraction had a greater discriminatory power between normal systolic pulmonary artery pressure, systolic pulmonary artery pressure lower than 50 mmHg, and pulmonary artery pressure greater than 50 mmHg. In conclusion, the role of many noninvasive echocardiographic parameters for assessment of the effects of pulmonary hypertension on right ventricle were investigated and it was found that right ventricular diameter and three-dimensional ejection fraction were the best parameters to reflect the effect of pulmonary hypertension on right ventricle. Key words: Pulmonary hypertension, systolic pulmonary artery pressure, right ventricle, echocardiography