Predictors of exercise-induced pulmonary hypertension in patients with connective tissue disease

Screening and early detection of pulmonary arterial hypertension (PAH) in connective tissue disease (CTD) are currently recommended for early treatment. Exercise-induced pulmonary hypertension (EIPH) is thought to be a potential risk of developing resting pulmonary hypertension. However, accurate diagnosis of EIPH is needed hemodynamics by right heart catheterization during exercise. Therefore, we compared various parameters of EIPH group with non-EIPH group in patients with CTD. This study aimed to investigate noninvasive predictors of EIPH. A total of 162 consecutive patients with CTD who received screening of PAH was studied. Thirty-four patients with suspected PAH received right heart catheterization (RHC) at rest. Twenty-four patients without PAH underwent RHC during exercise, and they were divided into the EIPH group (n = 7) and the non-EIPH group (n = 17). Exercise tolerance such as 6-min walk distance and peak VO₂/kg in the EIPH group was lower than that in the non-EIPH group. For hemodynamics, pulmonary artery pressure, right atrial pressure, and vascular resistance in the EIPH group were significantly higher than those in the non-EIPH group. In echocardiography, RV Tei index in the EIPH group was significantly higher than that in the non-EIPH group (EIPH vs non-EIPH = 0.42 [0.41, 0.47] vs 0.25 [0.20, 0.32], P = 0.007). The receiver operating characteristics curve showed a cutoff value of RV Tei index (0.41) with a sensitivity of 0.857 and specificity of 0.882. In conclusion, RV Tei index might be a feasible predictor of EIPH in patients with CTD.