A comparative study between various echocardiographic methods of screening for pulmonary hypertension in heart failure

Pulmonary hypertension (PH) is defined as mean pulmonary artery pressure (MPAP) ≥25mmHg. Right heart catheterization (RHC) is the gold standard for PH assessment but it has fallen out of fashion for the routine assessment of PH due to its invasiveness. More recently, Doppler echocardiography which is a non-invasive, cost-effective, and more readily available tool has become a favorable modality for the screening and serial assessment of PH in HF. The aim of this study was to identify Echocardiographic doppler correlates of pulmonary hypertension in heart failure patients. This study was carried out at the University of Benin Teaching Hospital (UBTH), Benin City, Edo state, Nigeria. The study population included one hundred and fifty patients (150) who were consecutively admitted into the medical wards for heart failure. This was a descriptive cross-sectional study where consenting patients who met the inclusion criteria were recruited consecutively. PASP, MPAP, PAAT,PADP, RVET and PAAT/RVET measurement were obtained, MPAP was derived from PASP using the Chemla formula. PH was defined as MPAP >25mmHg. Pulmonary artery acceleration time was measurable in all the subjects in the study population (100%), while TR was measurable in 104 (69.3%) of them. The prevalence of PH in HF using MPAP (PAAT) was 54%, while using PASP it was 44%. Tricuspid regurgitation was measurable in 104 (69.3%) subjects in the study population. The prevalence of pulmonary hypertension using PASP was 54%. This showed that patients with tricuspid regurgitation had significantly higher mean pulmonary artery pressure (p<0.001). Patients with PH had higher mean pulmonary artery systolic pressure of 47.4±1.5mmHg, while those without PH had mean pulmonary artery systolic pressure of 31.3±7.1mmHg (p = 0.017). Similarly, patients with pulmonary hypertension had higher mean pulmonary artery pressure of 32.7±6.4mmHg compared to patients without pulmonary hypertension (p < 0.001). The mean pulmonary artery pressure derived from pulmonary artery acceleration time (PAAT) was significantly higher in patients with PH. Patients with PH had mean pulmonary artery pressure of 38.4±3.1mmHg while those without PH had a mean value of 15.8±0.6 (p<0.001). A significant positive correlation was found between MPAP derived from PAAT and PASP in patients with PH, without PH and the total population (r=0.74, p=<0.001, r= 0.85, p<0.001, r= 0.90, p<0.001). There was a significant inverse relationship between PAAT/RVET and RVSP (p<0.001). Also, Linear regression analysis showed significant prediction of PASP from PAAT [ R2 = 0.641; F = 50.09 (p<0.001); B=1.34; β = 0.80; p<0.001]. Conclusion: Pulmonary hypertension is a common finding in patients admitted for heart failure. PAAT and PAAT/RVET have been shown to be excellent correlates of RVSP therefore utilizing them for technically difficult Echo procedures where good TR spectral Doppler flow cannot be gotten will be an invaluable tool.