Bronchiectasis increases the risk that a person with chronic obstructive pulmonary disease (COPD) will develop an enlarged pulmonary artery, a study reports.
The research, “Co-existence of COPD and bronchiectasis: a risk factor for a high ratio of main pulmonary artery to aorta diameter (PA:A) from computed tomography in COPD patients,” appeared in the journal International Journal of Chronic Obstructive Pulmonary Disease.
Pulmonary vascular disease, especially pulmonary hypertension, is a common complication of COPD and associated with high mortality. Bronchiectasis, which occurs in many patients, is considered not only a comorbidity of COPD, but also a risk factor for vascular disease.
The circulatory system has two main arteries. The pulmonary artery carries blood from the heart to the lungs, and the aorta carries blood from the heart to the rest of the body. The aorta is the largest blood vessel in the body.
The main pulmonary artery to aorta diameter ratio (PA:A ratio) is a reliable indicator of pulmonary vascular disease. It has also been found to be a good predictor of frequent exacerbations of COPD.
Patients with PA:A ratios of more than 1 are seen as having pulmonary artery enlargement. They display impaired physical activity and pulmonary hypertension.
Researchers hypothesized that the co-existence of COPD and bronchiectasis may be associated with pulmonary artery enlargement — or a PA:A ratio greater than 1.
In order to test this, the team did a retrospective study of patients with COPD. Patients were divided into two groups: the high ratio group, which included patients with a PA:A greater than 1, and the low ratio group, which included patients with PA:A equal to or less than 1. Patients were also divided into two groups according to the presence (or not) of bronchiectasis.
In total, 480 COPD patients were in the study, including 168 with bronchiectasis.
First, the PA:A ratio of the patients was determined. Patients with pulmonary artery enlargement had poorer nutrition, lower oxygen levels, a more severe airflow blockage, and a higher frequency of bronchiectasis than patients in the low ratio group.
Patients with both COPD and bronchiectasis also had higher levels of systemic inflammation and higher PA:A ratios. Furthermore, a higher PA:A ratio was closely associated with a higher bronchiectasis severity score.
Researchers ran multiple statistical analyses to determine risk factors. They found that bronchiectasis is a risk factor for high PA:A ratios in COPD patients.
“COPD and bronchiectasis co-existence subjects are considered at risk for relative pulmonary artery enlargement (PA:A ratio > 1),” the team concluded. “Future comprehensive assessment should pay close attention to the prevalence of and mechanisms underlying pulmonary vascular disease in patients with COPD and concomitant bronchiectasis.”