Increased Pulmonary Arterial Compliance after Balloon Pulmonary Angioplasty Predicts Exercise Tolerance Improvement in Inoperable CTEPH Patients with Lower Pulmonary Arterial Pressure.

BACKGROUND:Balloon pulmonary angioplasty (BPA) improved pulmonary arterial compliance (CPA) and exercise tolerance in patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH). OBJECTIVES:To investigate whether CPA is a useful index to indicate exercise tolerance improvement by BPA in CTEPH patients. METHODS:The correlation between changes in CPA and improvements in 6-minute walk distance (6MWD) by BPA was retrospectively analyzed in 70 patients (Analysis 1), and it was sequentially analyzed in 46 symptomatic patients who achieved mean pulmonary arterial pressure (mPAP)<30mmHg (Analysis 2). RESULTS:We enrolled 70 patients (female/male:57/13, mean age:59 years) who underwent a total of 352 BPA sessions which significantly increased CPA (1.5±0.8 vs. 3.0±1.0 mL/mmHg) and decreased pulmonary vascular resistance (PVR) (8.0 ± 3.9 vs. 3.6 ± 1.7 wood units). The correlation coefficient between improvement in 6MWD and changes in PVR and CPA were r=0.21 (p=0.09) and r=0.14 (p=0.26) (Analysis 1). In Analysis 2, those were r=0.32 (p=0.06) and r=0.38 (p=0.02), respectively. CONCLUSIONS:CPA can be a useful index to indicate the improvement in exercise tolerance by BPA in symptomatic patients with lower mPAP.