Comparison of Hemodynamic Responses to Balloon Pulmonary Angioplasty in Chronic Thromboembolic Pulmonary Hypertension in Japan and The Netherlands: A Multicenter Study.

BACKGROUND: Mean pulmonary arterial pressure (mPAP) after balloon pulmonary angioplasty (BPA) in patients with chronic thromboembolic pulmonary hypertension (CTEPH) consistently has been lower in Japan compared with non-Japanese cohorts.

RESEARCH QUESTION: What factors are associated with higher mPAP after BPA?

STUDY DESIGN AND METHODS: This retrospective multicenter study screened 200 consecutive patients with CTEPH who underwent BPA at 2 centers in The Netherlands and 2 centers in Japan. After excluding patients with prior pulmonary endarterectomy or lacking follow-up hemodynamic data, 138 patients were analyzed. Comorbidities, lesion distribution and morphologic features, PH medication, procedural details, and hemodynamic parameters were compared between the 2 countries' cohorts. Multivariable regression analysis was performed to identify factors associated with high mPAP at follow-up.

RESULTS: The proportion of male patients (55% vs 24%), BMI (mean [SD], 26 [4] kg/m2 vs 23 [5] kg/m2), the prevalence of atrial fibrillation (9% vs 0%), and smoking rate (43% vs 23%) were higher and diffusing capacity of the lung for carbon monoxide (Dlco) was lower (mean [SD], 69% [15%] vs 79% [19%]) in the cohort from The Netherlands. Proximal lesion distribution and severity on CT imaging were comparable between the 2 countries. The Japanese cohort demonstrated a greater mPAP reduction (-16 mm Hg [40%] vs -10 mm Hg [28%]; P < .01 ), with a lower mPAP at follow-up (mean [SE], 22 [1] mm Hg vs 30 [1] mm Hg; P < .01). Independent factors associated with higher follow-up mPAP included lower Dlco, higher right atrial pressure, higher pulmonary arterial wedge pressure at follow-up, a greater number of BPA sessions, and less frequent use of intermediate-sized balloons.

INTERPRETATION: Our results show that higher mPAP after BPA was associated with impaired lung and left-sided heart function and procedural parameters, rather than nationality or lesion distribution. These findings suggest that occult cardiopulmonary comorbidities are important contributors to international differences in BPA outcomes and that differences in procedural practice may play a role.