Arterial stiffness is independently associated with emphysema severity in patients with chronic obstructive pulmonary disease

Abstract

Rationale: More patients with chronic obstructive pulmonary disease (COPD) die of cardiovascular causes than of respiratory causes, and patients with COPD have increased morbidity and mortality from stroke and coronary heart disease. Arterial stiffness independently predicts cardiovascular risk, is associated with atheromatous plaque burden, and is increased in patients with COPD compared with control subjects matched for cardiovascular risk factors. Elastin fragmentation and changes in collagen are found in the connective tissue of both emphysematous lungs and stiff arteries, but it is not known whether the severity of arterial stiffness in patients with COPD is associated with the severity of emphysema.

Objectives: To identify whether the extent of arterial stiffness is associated with emphysema severity.

Methods: We performed a cross-sectional study in 157 patients with COPD.

Measurements and main results: We measured pulse wave velocity (a validated measure of arterial stiffness), blood pressure, smoking pack-years, glucose, cholesterol, and C-reactive protein in 157 patients with COPD. We assessed emphysema using quantitative computed tomography scanning in a subgroup of 73 patients. We found that emphysema severity was associated with arterial stiffness (r = 0.471, P < 0.001). The association was independent of smoking, age, sex, FEV(1)% predicted, highly sensitive C-reactive protein and glucose concentrations, cholesterol-high-density lipoprotein ratio, and pulse oximetry oxygen saturations.

Conclusions: Emphysema severity is associated with arterial stiffness in patients with COPD. Similar pathophysiological processes may be involved in both lung and arterial tissue and further studies are now required to identify the mechanism underlying this newly described association.

Figure 1.

Associations between emphysema severity, FEV₁% predicted and arterial stiffness in the high-resolution computed tomography subgroup. Scatter plots of pulse wave velocity on emphysema severity (A), and airflow limitation (B). Scatter plot of emphysema severity on airflow limitation (C). Bar chart of percentage change between first quartile of pulse wave velocity and higher quartiles in terms of airflow limitation (1 − FEV₁% predicted) and emphysema severity (pixel index 910) (D).