Lung field alters effect of BPA on respiratory function in CTEPH patients
The effect of balloon pulmonary angioplasty on respiratory function in patients with chronic thromboembolic pulmonary hypertension varied depending on the lung field, according to research published in CHEST.
“Recently, balloon pulmonary angioplasty (BPA) has been reported to improve hemodynamics and functional capacity in patients with chronic thromboembolic pulmonary hypertension (CTEPH) who are not candidates for pulmonary endarterectomy. However, BPA effect on respiratory functions is unclear,” Mina Akizuki, PT, from the department of rehabilitation at Tokyo Women’s Medical University. “BPA changes ventilation/perfusion (V/Q) ratio by improving pulmonary blood flow, and BPA effect on respiratory functions may vary depending on BPA fields, such as lower or upper-middle lung fields at rest and during exercise.”
The researchers investigated how BPA affects hemodynamics, ventilator efficiency, and gas exchange in patients with CTEPH using right heart catheterization, respiratory function test, and cardiopulmonary exercise testing (CPX). The investigators performed 62 BPA sessions in 13 consecutive patients. They enrolled patients with inoperable CTECH who underwent BPA in lower lobe arteries (first series) and upper and middle lobe arteries (second series), then compared changes in hemodynamics and respiratory function between different BPA fields.
Akizuki and colleagues found mean pulmonary artery pressure and pulmonary vasculature resistance improved from 44 ± 8 to 23 ± 5 mmHg and 818 ± 383 to 311 ± 117 dyne/s/cm-5. The researchers observed percentage of predicted carbon monoxide lung diffusion capacity (%DLco) decreased after BPA in the lower-lung field (from 60 ± 8% to 54 ± 8%) with no recovery. In comparison, %DLco increased after BPA in the upper-middle lung field (from 53 ± 6% to 58 ± 6%) and continued to raise during follow-up (from 58 ± 6 % to 64 ± 11%).
The results showed changes in %DLco and the ventilation/carbon dioxide production (VE/VCO2) slope differed between lower and upper-middle lung fields. The VE/VCO2 slope increased after BPA in the lower-lung field (from 51 ± 13 to 41 ± 8) and continued to increase during follow-up (from 41 ± 8 to 35 ± 7). However, the investigators found after BPA in the upper-middle lung field, the VE/VCO2 slope remained unaffected.
“Based on our results, we suggest that BPA in the lower lung field improves oxygenation and respiratory function parameters during exercise, such as VE/VCO2 slope, because of remarkable improvement in hemodynamics,” Akizuki and associates wrote. “BPA in the upper-middle lung field may improve oxygenation and respiratory function parameters at rest, such as %DLco, cause by improvement in V/Q mismatch.” — by Savannah Demko
Disclosure: The researchers report no relevant financial disclosures.