Clinical impact of mean pulmonary arterial pressure after balloon pulmonary angioplasty for inoperable chronic thromboembolic pulmonary hypertension.

Background: Balloon pulmonary angioplasty (BPA) improves haemodynamics in patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH). Previous studies on BPA have set the treatment objective to achieve a mean pulmonary arterial pressure (mPAP) of <30 mm Hg. However, the clinical impact of mPAP after BPA remains unclear. This study aimed to stratify patients according to their mPAP after BPA and evaluate its association with clinical status and long-term outcomes.

Methods: We retrospectively reviewed 304 patients with inoperable CTEPH (median age, 72 (61 to 79) years) who underwent BPA and follow-up right heart catheterisation. Patients were categorised by mPAP after BPA: ≤20, >20-<30 and ≥30 mm Hg groups.

Results: The WHO functional classification, 6 min walk distance and right ventricular ejection fraction were significantly better in the group with a lower mPAP (trend test p=0.007, p<0.001 and p=0.002, respectively). Additionally, the proportions of patients who required pulmonary vasodilators or oxygen therapy were significantly lower in the group with a lower mPAP (trend test p<0.001 and p<0.001, respectively). Across all multivariable models, the mPAP ≥30 mm Hg group had a significantly poorer prognosis compared with the mPAP ≤20 mm Hg group. In contrast, no significant difference was observed between the mPAP ≤20 mm Hg and >20-<30 mm Hg groups.

Conclusions: In patients with CTEPH after BPA, an mPAP of <30 mm Hg was associated with a favourable prognosis, and patients with an mPAP of ≤20 mm Hg presented with better symptoms, exercise capacity, right ventricular function and more withdrawal from oxygen therapy and pulmonary vasodilators. The BPA treatment goal may require individual adaptation.