Reduction in Right Ventricular Stroke Work Index After Balloon Pulmonary Angioplasty is Associated With Long-Term Prognosis in Chronic Thromboembolic Pulmonary Hypertension.

The prognostic relevance of the relative change in right ventricular stroke work index (RVSWI) after balloon pulmonary angioplasty (BPA) in chronic thromboembolic pulmonary hypertension (CTEPH) remains uncertain. This retrospective single-center study included 38 patients with CTEPH. Follow-up began at post-BPA catheterization. Relative change in RVSWI (%RVSWI; negative values indicate reduction) and conventional measures were compared using Cox models and direction-fixed C-indices. Bootstrap resampling assessed selection optimism across 14 candidates. RVSWI decreased from 16.96 to 9.83 g·m/m2/beat. During a median 4.1 years, 7 patients reached the composite endpoint of all-cause death or heart failure hospitalization. A smaller reduction was associated with higher risk (hazard ratio 1.24 per 1 percentage-point increase in %RVSWI, 95% confidence interval 1.06-1.44; p = 0.007). %RVSWI had the highest apparent C-index (0.942, 95% confidence interval 0.86-0.99), but its difference from achieved mean pulmonary artery pressure (C-index 0.855) was not statistically distinguishable. %RVSWI ranked first in 62% of bootstrap resamples; the optimism-corrected C-index was 0.922. Component log-ratios were essentially uncorrelated (r = 0.01, 95% confidence interval -0.31 to 0.33). Greater RVSWI reduction after BPA was associated with better prognosis. With seven events, these findings are hypothesis-generating; superiority over conventional measures and the physiological interpretation of the SVI component remain unestablished.