Abstract
Background
Clinical risk stratification in pulmonary arterial hypertension (PAH) relies on BNP level, NYHA functional class, 6min-walk distance and cardiac output by right heart catheterization (RHC) with no place for non-invasive mean like echocardiography.
Purpose
To avoid systematic RHC in PAH patients, we aimed to determine both tricuspid peak systolic S wave tissue Doppler velocity (S-DTI, cm/s) and tricuspid annular plane systolic excursion (TAPSE, mm) cut-off values that best correlated to invasive cardiac index ≥2.5l/min/m² (CI, meaning low risk clinical worsening or death) in an initial cohort and to test them in a validation cohort.
Methods
From a single referral pulmonary hypertension centre, 125 PAH patients (initial cohort) underwent 406 hemodynamic investigations with RHC and echocardiography on the same day. S-DTI and TAPSE were performed from a standard manner following the 2015 EACVI/ASE recommendations. This initial cohort served for the receiver operating characteristic analysis from which the cut-off values were investigated in a validation cohort, to test the cardiac index stratification.
Results
The initial cohort had a mean age of 66.9 ± 14.4 y. Mean pulmonary artery pressure averaged 44 ± 12 mmHg, CI was 2.8 ± 1.0 l/min/m2, S-DTI was 11.2 ± 2.9 cm/s and TAPSE was 18.4 ± 4.7 mm. Both pulsed S-DTI and TAPSE were correlated to invasive CI (p < 0.001 and p < 0.0001, respectively). S-DTI ≥12 cm/s or between <12 cm/s and ≥10 cm/s with TAPSE > 17 mm had a specificity of 0.89 and 0.90, respectively to detect CI ≥ 2.5l/min/m² from the ROC curve analysis. Applying this cutoff-based stratification provided similar results in the validation cohort of 97 PAH patients (mean age = 65 ± 16 y, mean pulmonary artery pressure = 45 ± 16 mmHg, CI = 3.0 ± 1.0 l/min/m2, while S-DTI = 11.1 ± 3.1 cm/s, TAPSE = 17.8 ± 5.4 mm). Overall, almost 50% of patients were appropriately classified avoiding RHC
Conclusion
Considering tricuspid peak systolic S wave tissue Doppler velocity ≥12 cm/s or <12 cm/s but ≥10 cm/s with tricuspid annular plane systolic excursion by M-mode >17 mm, then RHC may be avoided in almost 50% of patient to predict CI≥2.5l/min/m² in PAH patients.