Prevalence and Clinical Correlates of Radiologically Detected Coronary Artery Disease in COPD: A Cross-Sectional Observational Study

Unrecognised coronary artery disease (CAD) may contribute to adverse outcomes in chronic obstructive pulmonary disease (COPD). Improved identification of at-risk groups could inform better preventative care. We aimed to evaluate the burden and relationships of radiologically detectable CAD in COPD, establish frequency of occult disease, and examine potential cardiovascular screening methods. Using CT coronary angiogram (CTCA), we prospectively evaluated CAD in 50 patients with COPD compared to age, sex-matched controls. In those with COPD, the relationship of CAD to cardiac symptoms (chest pain, dyspnoea), functional capacity (six-minute walk), exacerbations and inflammation was assessed. The performance of screening tests (cardiovascular risk scores, biomarkers and CT thorax-derived coronary artery calcium score (CACS-Tx)) were evaluated using receiver operator curves. CAD was present in 88% of patients with COPD (42% had obstructive (≥50% stenosis of any vessel) and 28% severe obstructive (≥70%) disease). Rates of obstructive (OR 3·1 (95%CI 1·1-8·9) P=0·037) and severe obstructive CAD (OR 10·1(95%CI 1·9-52·7) P=0·006) were higher in COPD than controls. In the COPD group, those with CAD had greater functional impairments but not dyspnoea scores, and 75% reported no chest pain or prior IHD. CAD was more extensive in those with increased systemic inflammation (fibrinogen, c-reactive protein, leucocyte, and neutrophil count), bronchial wall thickening, and sputum bacterial growth but bore no relation to exacerbation frequency. CACS-Tx was an effective screening tool, with an area under the curve for CAD of 0·98 (95%CI 0·95-1·00) and obstructive CAD of 0·89 (95%CI 0·79-1·00). CTCA-detected CAD is common in patients with COPD, correlating poorly with symptoms and risk scores. Radiological screening, using CT thorax, might improve detection and outcomes in this patient group.