Exercise tolerance in patients with chronic thromboembolic pulmonary hypertension after balloon pulmonary angioplasty.

BACKGROUND

Balloon pulmonary angioplasty (BPA) is an effective therapeutic alternative for patients with chronic thromboembolic pulmonary hypertension (CTEPH), which improved pulmonary arterial compliance (CPA) and pulmonary vascular resistance (PVR).

OBJECTIVE

To investigate whether the CPA is a predictor of exercise tolerance after BPA.

METHODS

The correlations between changes in each parameter and changes in six-minute walking distance (6MWD) were evaluated by Pearson's test. The determinants of functional capacity that was defined as 6MWD ≥440 m were assessed with a logistic regression model. Multiple linear regression analysis was used to identify the independent variables related to △6MWD.

RESULTS

We enrolled 70 patients (female/male: 40/30, mean age: 64 years) who underwent a total of 271 BPA sessions which significantly increased CPA [1.0 (0.7, 1.3) vs. 2.1 (1.7, 2.5) mL/mmHg], and decreased PVR [6.7 (3.6, 9.7) vs. 3.0 (2.1, 4.3) wood units]. The correlation coefficient between improvement in 6MWD and changes in CPA was r = 0.328 (P = 0.006). At univariate analysis, duration of pulmonary hypertension symptoms and pulmonary arterial compliance were found to be associated with good exercise tolerance. Multivariate analysis demonstrated that CPA (95 %CI: 1.23 to 3.75, P = 0.026) was an independent predictor of exercise tolerance after BPA. The multiple linear regression analysis demonstrated that △CPA (β= 0.292, P = 0.019) was an independent predictor of △6MWD.

CONCLUSION

BPA significantly improved CPA in inoperable patients with CTEPH and the resistance-compliance relationship maintained inversely associated. After successful BPA, baseline CPA is an important determinant of exercise tolerance.