New Echocardiographic Tehniques in Pulmonary Arterial Hypertension vs. Right Heart Catheterization - A Pilot Study.

Background: Pulmonary arterial hypertension (PAH) represents an emerging pathology in modern medicine. Transthoracic echocardiography is an inexpensive and reproducible method and it is the most commonly used non-invasive diagnostic tool to asses pulmonary artery pressure (PAP) and the function of the right ventricle. Although, the right heart catheterization is still considered as the standard for the diagnosis, according to the last guidelines, the new echocardiographic methods may offer an improved value in the PAH evaluation.

Aim: To evaluate if cardiac ultrasonography data correlate with catheterization results in patients with PAH (Group I Dana Point 2008), and to compare the ultrasonography evaluation of PAH patients with that of normal.

Methods: 15 consecutive patients (pts) (52±15 yrs, 5 men, time from onset of symptoms 1.6±1.7 years) with PAH of different aetiologies (12 pts with idiopathic PAH, 2 pts with PAH associated with scleroderma and one with persistent PAH after atrial septal defect (ASD) closure) were evaluated through: 1. clinical examination (NYHA class); 2. exercise capacity (6 minute walking test - 6MWT); 3. conventional echocardiography (diameter of right ventricle - RVD and right atrium, fractional area shortening - FAS, TAPSE, pulmonary ascension time - PA, systolic and mean PAP -sPAP, mPAP, tricuspid E/A ratio, cardiac index-CI) and 4. Tissue Doppler Imaging - TDI (systolic and diastolic myocardial velocities at the tricuspid annulus - S, D, A); 5. right heart catheterization (sPAP, mPAP, CI, pulmonary vascular resistance - PVR)We compared classical and TDI echo parameters with those obtained from 15 normal subjects, matched in age and sex.

Results: PAH patients had high sPAP and mPAP with right heart dilation (RV - 44.8±7.3 mm), depressed TAPSE (16.2±5.9 mm) and cardiac index and low TDI systolic velocities at tricuspid level (7.3±2.9 cm/s). All parameters differed statistically significant from normal. There were no significant correlations between ultrasonography and catheterization (cath) parameters (sPAP 92±28.2 echo vs. 106.4±25.8 mmHg cath; mPAP 47.9±8.4 echo vs. 65.8±17.3 mmHg cath), excepting for CI 2.3±1.2 l/min/m(2) vs. 2.08±0.3 ml/min/m(2)) and PVR (16.5 ± 15.3 Wood U echo, vs. 19.6 ± 7.9 cath).

Conclusion: Classic and TDI cardiac ultrasonography represents a good screening and monitoring tool for PAH patients, but tends to underestimate the severity of the disease, leaving right heart catheterization as the essential diagnostic method for this rare disease.