Spontaneous hemodynamic improvement after balloon pulmonary angioplasty in patients with chronic thromboembolic pulmonary hypertension is observed within a short term after balloon pulmonary angioplasty

Natural hemodynamic changes after balloon pulmonary artery angioplasty (BPA) in a unified state without oxygen administration in patients with chronic thromboembolic pulmonary hypertension (CTEPH) remains undetermined. This study aimed to clarify the delayed changes in the hemodynamics after BPA in patients with CTEPH. We analyzed 73 consecutive patients with CTEPH who underwent BPA between July 2014 and December 2022. We extracted and evaluated hemodynamic data of the right heart catheter without oxygen administration immediately before and after the first BPA; and immediately before the second BPA, as the "post-delayed changes" after BPA. BPA significantly improved the mean pulmonary artery pressure (mPAP, mmHg) and pulmonary vascular resistance (PVR, dyn-s/cm5) from 36 (32-43) mmHg and 449 (312-627) dyn-s/cm5 before the first BPA to 28 (23-32) mmHg and 275 (217-366) dyn-s/cm5 immediately after BPA, and further significantly improved the values to 23 (20-28) mmHg and 225 (175-301) dyn-s/cm5 post-delayed changes after BPA, respectively. Improvement observed on account of delayed changes was observed both with and without pulmonary hypertension drugs. The delayed changes were observed during a period of 5-180 days, which did not correlate with the changes in mPAP and PVR. Hemodynamic improvement owing to BPA was observed immediately after BPA; however, further improvement was observed as a result of delayed changes. mPAP improved by 3.4 +/- 5.2 mmHg and PVR by 53 (10-99) dyn-s/cm5 as delayed improvement. mPAP and PVR showed delayed improved by approximately 10% of their values before BPA.Graphical abstractSpontaneous hemodynamic improvement after balloon pulmonary angioplasty. BPA, balloon pulmonary angioplasty; CTEPH, chronic thromboembolic pulmonary hypertension; RHC, right heart catheterization