Respiratory, cardiovascular and systemic factors associated with brain damage in Chronic Obstructive Pulmonary Disease (COPD) and/or coronary artery disease (CAD)

Abstract

Background: Brain damage and mild cognitive impairment are frequent comorbidities of COPD, and are also associated with smoking and CAD.

Aims and objectives: To investigate possible common mechanisms for brain damage in COPD and CAD.

Methods: Where possible, principal component analysis (PCA) was used to group disease markers within organ systems into composite markers. Relationships between brain damage and other organ systems were tested using correlations and multiple regression.

Results: 100 patients were studied (53 COPD, 23 CAD, 24 CAD + COPD); COPD patients met ATS/ERS criteria, CAD diagnosed by angiography. PCA identified two brain components: cerebral atrophy and white matter microstructural damage and six components from other organ systems: respiratory function, plasma lipids, blood pressure, glucose dysregulation, retinal vessel calibre and retinal vessel tortuosity. Several markers did not form components, including brain white matter lesion volume (WMLV). These were analysed as single variables.

Multiple regression showed that white matter microstructural damage was associated with lower respiratory function, higher blood pressure and higher troponin T; WMLV was associated with higher blood pressure; cerebral atrophy was associated with lower cerebral blood flow and higher blood pressure (all significant at p<0.05). Smoking history was not an independent marker of brain damage.

Conclusions: A range of disease markers in other organs were associated with brain damage in patients with COPD and/or CAD. Whilst no single common pathway was identified, the findings are compatible with vascular mediated brain damage.