Undiagnosed airflow limitation is common in patients with coronary artery disease and associated with cardiac stress.
OBJECTIVE
Smoking is a common risk factor for coronary artery disease (CAD) and chronic obstructive pulmonary disease (COPD). We evaluated the prevalence of undiagnosed COPD in patients with CAD and assessed the relationship between airflow obstruction and markers of cardiac stress.


METHODS
We recruited prospectively consecutive patients aged >40 years without known history of chronic lung disease (e.g. asthma, COPD, bronchiectasis) who had undergone percutaneous coronary intervention (PCI) for obstructive CAD between August 2009 and October 2010. Spirometry was performed and serum ST2, a novel biomarker of cardiomyocyte stress and fibrosis, was measured by enzyme-linked immunosorbent assay.


RESULTS
Among 475 subjects (mean age 64 ± 9.7, range 42-85 years, 87.2% males, 58.5% current or ex-smokers) who underwent spirometry, 51 (10.7%) had undiagnosed airflow obstruction with FEV1 /FVC ratio <70%. Of these 51 subjects, 14 (2.9%), 23 (4.8%) and 14 (2.9%) had FEV1 ≥80, 50-80 and 30-50% predicted normal, respectively. ST2 level was measured in all the subjects with undiagnosed airflow obstruction and in 290 subjects with normal lung function. There was no significant difference in left ventricular ejection fraction on echocardiogram between subjects with and without airflow obstruction. Patients with severe airflow obstruction had a higher level of cardiac stress marker ST2 than those with mild and moderate airflow obstruction (rho = -0.214, P ≤ 0.001).


CONCLUSIONS
Undiagnosed airflow obstruction is common among patients with CAD who have undergone PCI. Severity of airflow limitation is associated with increasing cardiac stress.
Division of Respiratory Medicine, Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, China.
Fanny W S
FW
Ko
Division of Cardiology, Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, China.
Bryan P
BP
Yan
Division of Cardiology, Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, China.
Yat-yin
YY
Lam
Division of Respiratory Medicine, Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, China.
Jojo H Y
JH
Chu
Division of Respiratory Medicine, Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, China.
Ka-Pang
http://orcid.org/0000-0002-8163-5846
KP
Chan
Division of Respiratory Medicine, Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, China.
David S C
DS
Hui
D000368:Aged; D000402:Airway Obstruction / Q000175:diagnosis* / Q000503:physiopathology; D015415:Biomarkers / Q000097:blood; D002681:China / Q000453:epidemiology; D003324:Coronary Artery Disease / Q000097:blood / Q000150:complications / Q000453:epidemiology / Q000503:physiopathology / Q000601:surgery; D003951:Diagnostic Errors / Q000517:prevention & control*; D005260:Female; D006801:Humans; D000072179:Interleukin-1 Receptor-Like 1 Protein; D008297:Male; D008875:Middle Aged; D062645:Percutaneous Coronary Intervention / Q000706:statistics & numerical data; D015995:Prevalence; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology; D011956:Receptors, Cell Surface / Q000097:blood*; D017472:Receptors, Interleukin-1 / Q000097:blood; D012307:Risk Factors; D012907:Smoking / Q000453:epidemiology / Q000503:physiopathology; D013147:Spirometry / Q000379:methods; D013223:Statistics as Topic
D015415:Biomarkers; C079241:IL1RL1 protein, human; D000072179:Interleukin-1 Receptor-Like 1 Protein; D011956:Receptors, Cell Surface; D017472:Receptors, Interleukin-1
ST2; airflow obstruction; cardiac stress; chronic obstructive pulmonary disease; coronary artery disease