Loss of small, distal pulmonary arteries associated with bronchiectasis progression

The loss of small, distal pulmonary arteries was associated with progression of CT-derived bronchiectasis, especially among smokers with COPD, according to results published in Respiratory Medicine Journal.

“Smokers with bronchiectasis present a loss of small, distal pulmonary vessels, and children with cystic fibrosis bronchiectasis and adults who underwent surgery due to bronchiectasis manifest a loss of small pulmonary arteries and capillary beds,” Wojciech R. Dolliver, MD, research assistant in the division of pulmonary and critical care medicine at Brigham and Women’s Hospital, and colleagues wrote. “Therefore, this study aimed to test the hypothesis that intra-parenchymal pulmonary arterial pruning is associated with bronchiectasis progression, using techniques applied on noncontract CT that allow to objectively assess in vivo vascular trees.”

Researchers evaluated bronchiectasis on CT at baseline and 5 years later among 386 participants (mean age, 64 years; 41% women) with 10 or more pack-years smoking history with (n = 185) and without (n = 201) COPD. Researchers visually scored bronchiectasis, with higher scores indicating more severe disease. They also measured vascular pruning with use of the ratio of blood vessel volume in arteries less than 5 mm² in cross-section to total arterial blood vessel volume (BV5a:BVTa) on baseline CTs; lower values indicated more pruning.

Participants with more arterial pruning were more likely to be non-Hispanic Black women compared with those with less arterial pruning (36% vs. 18%; P = .001). These participants also had lower FEV₁ (1.73 L vs. 2.24 L; P < .001), 6-minute walk distance (1,268 ft vs. 1,447 ft; P < .001) and resting oxygen saturation (96% vs. 97%; P = .0008) as well as higher baseline 10 mm inner perimeter airway (2.43 mm vs. 1.89 mm; P < .001) compared with participants with less arterial pruning, the researchers wrote.

Overall, 34.5% of participants met the definition of CT-derived bronchiectasis progression, with a mean 5-year change of an increase of 5.7 points. Researchers reported an increase in pulmonary segments with bronchiectasis as the main contributor to score changes, followed by the extent of airway wall thickness severity and airway dilation severity.

In addition, the baseline BV5a:BVTa ratio was associated with 5-year progressing CT-derived bronchiectasis per 5% lower BV5a:BVTa (OR = 1.28; 95% CI, 1.07-1.53; P = .007). Among those with COPD, the corresponding OR was 1.45, according to the researchers.

“These results extend this knowledge by revealing that disappearance of small pulmonary arteries is associated with structural bronchiectasis progression, and they are in line with studies demonstrating that pulmonary vascular pruning is associated with other chronic airway disease, COPD and asthma,” the researchers wrote.