Structural analysis of retinal blood vessels in patients with COPD during a pulmonary rehabilitation program

Anouk W Vaes,Martijn A Spruit,João Barbosa-Breda,Patrick De Boever,Frits M E Franssen,Jan Theunis,Emiel F M Wouters,Karel Van Keer

doi:10.1038/s41598-019-56997-5

Abstract

Cardiovascular diseases are frequently present in chronic obstructive pulmonary disease (COPD). Population-based studies found associations between retinal vessel diameters and cardiovascular health, but it is unknown whether this also applies to COPD patients. Therefore, we measured retinal vessel diameters in COPD patients and aimed to determine the association with cardiovascular risk factors, lung function, and functional outcomes. In addition, we investigated whether an exercise-based pulmonary rehabilitation (PR) program would change retinal vessel diameters, as a proxy for improved microvascular health. Demographics and clinical characteristics, including pulmonary function, exercise capacity, blood pressure, blood measurements and level of systemic inflammation were obtained from 246 patients during routine assessment before and after PR. Retinal vessel diameters were measured from digital retinal images. Older age and higher systolic blood pressure were associated with narrower retinal arterioles (β: −0.224; p = 0.042 and β: −0.136; p < 0.001, respectively). Older age, higher systolic blood pressure and lower level of systemic inflammation were associated with narrower retinal venules (β: −0.654; −0.229; and −13.767, respectively; p < 0.05). No associations were found between retinal vessel diameters and lung function parameters or functional outcomes. After PR, no significant changes in retinal venular or arteriolar diameter were found. To conclude, retinal vessel diameters of COPD patients were significantly associated with systolic blood pressure and systemic inflammation, whilst there was no evidence for an association with lung function parameters, functional outcomes or other cardiovascular risk factors. Furthermore, an exercise-based PR program did not affect retinal vessel diameter.

Highlights

Chronic obstructive pulmonary disease (COPD) is characterized by persistent respiratory symptoms and airflow limitation due to airway and/or alveolar abnormalities usually caused by significant exposure to noxious particles or gases[1]
We showed that retinal arteriolar and venular diameters were independently associated with systolic blood pressure, whereas retinal venular diameter was related to systemic inflammatory status and age
Retinal vessel diameters were not associated with important functional outcomes of pulmonary rehabilitation

Summary

Introduction

Chronic obstructive pulmonary disease (COPD) is characterized by persistent respiratory symptoms and airflow limitation due to airway and/or alveolar abnormalities usually caused by significant exposure to noxious particles or gases[1]. Data from a population study suggest that the width of retinal venules is inversely associated with forced expiratory volume in one second (FEV1) and FEV1/forced vital capacity (FVC)[26,27]. This would indicate that vascular comorbidities associated with obstructive decrements in lung function may be characterized by defects in the microvascular circulation, as assessed with fundus imaging[26]. Based on similarities with type 2 DM and heart failure, we postulated that the microcirculation, as assessed by retinal vessel diameters, is inversely associated with systemic cardiometabolic parameters and functional outcomes in patients with COPD22–24

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