Smoking, sleep apnoea tied to coronary microvascular dysfunction

Current smoking and respiratory diseases independently contribute to coronary microvascular disease (CMD) in patients undergoing invasive coronary microvascular evaluation, suggests a study. Moreover, higher pack-years among smokers strongly predict CMD.

The analysis involved 266 patients (mean age 67 years, 59 percent females), of whom 155 (58 percent) had evidence of CMD.

Among the respiratory variables assessed, current smoking (adjusted odds ratio [AOR], 2.5, 95 percent confidence interval [CI], 1.2‒5; p=0.01) and obstructive sleep apnoea (AOR, 5.7, 95 percent CI, 1.2‒26; p=0.03) independently predicted CMD, but chronic obstructive pulmonary disease did not.

Among smokers, those with higher smoking pack-years were more likely to develop CMD (median 35 vs 25 pack-years: AOR, 1.09, 95 percent CI, 1.04‒1.13; p<0.01) and were found to have higher rates of pathologic index of microcirculatory resistance and resistive reserve ratio.

“Our findings should raise awareness for prevention and possible treatment options,” the authors said.

This observational, single-centre study enrolled consecutive patients undergoing invasive evaluation of coronary microvascular function in the catheterization laboratory. Those with evidence of obstructive coronary artery disease or with missing data were excluded from the analysis.

Univariate and multivariate regression models were used to explore the relationships between respiratory-related variables and indices of CMD.

“CMD is common in patients with and without obstructive coronary artery disease, and is associated with adverse clinical outcomes,” the authors said.