The bidirectional relationship between chronic obstructive pulmonary disease and coronary artery disease.

Chronic obstructive pulmonary disease (COPD) and coronary artery disease (CAD) not only have smoking as a common risk factor, they also share epidemiological relationships and important mutual effects. There is good evidence to suggest that COPD is highly prevalent but underdiagnosed among CAD patients and vice versa. The symptoms of the two diseases can overlap, making differential diagnosis challenging. This highlights the importance of pulmonary function tests (PFTs) in patients with CAD but also a cardiological assessment in patients with COPD. Chronic obstructive pulmonary disease is a risk factor for the development of CAD independent of other cardiovascular risk factors, and the presence of COPD worsens prognosis in patients with CAD. Mechanisms underlying the associations between COPD and CAD have been less well studied, but inflammation is increasingly being recognized as an important factor linking the two diseases. Other potential contributors include increased oxidative stress, platelet activation, and arterial stiffness. The influence of medications used to treat one condition on the other one needs to be understood and taken into account in patient management. Physicians need to be aware of the important links between COPD and CAD, both of which are commonly encountered in clinical practice. This should help to optimize the management of both conditions to improve patient outcomes.