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Sleep apnea linked to subclinical myocardial injury
Results from a new study indicate that obstructive sleep apnea is associated with subclinical myocardial injury and that high-sensitivity troponin T may serve as an early marker of the adverse myocardial impact of obstructive sleep apnea.
“Although obstructive sleep apnea is associated with increased cardiovascular risk, a causal association has been hard to establish because of the association of obstructive sleep apnea with other risk factors,” Amil M. Shah, MD, MPH, of Brigham and Women’s Hospital, said in a press release. “In our study, we were able to demonstrate that greater obstructive sleep apnea severity is independently associated with higher high-sensitivity troponin T levels, suggesting a role for subclinical myocardial injury in the relationship between obstructive sleep apnea and heart failure.”
This is the first study to demonstrate an independent association between sleep apnea severity and this marker of early myocardial injury, the researchers said.
The study included 1,645 middle-aged and older participants in the Atherosclerosis Risk in Communities (ARIC) study and the Sleep Health Study. All were free of CHD and HF at baseline. Median follow-up was 12.4 years. Participants underwent overnight home polysomnography. Obstructive sleep apnea severity, measured by the respiratory disturbance index (RDI), was categorized as none (RDI ≤5), mild (RDI 5-15), moderate (RDI 15-30) or severe (RDI ≥30).
High-sensitivity troponin T levels, but not NT-proBNP levels, were significantly associated with obstructive sleep apnea after adjustment for 17 potential confounders (P=.02). In all obstructive sleep apnea severity categories, high-sensitivity troponin T was significantly related to the risk for death or incident HF; this relationship was strongest in the severe obstructive sleep apnea group.
Limitations of the study include its cross-sectional design and a limited number of participants with obstructive sleep apnea.
“Our results suggest a relationship between subclinical myocardial injury and the increased cardiovascular risk seen in patients with obstructive sleep apnea,” Shah said. “Monitoring of high-sensitivity troponin T levels in these patients may have prognostic value, particularly in patients with severe obstructive sleep apnea.”
Disclosure: The researchers report no relevant financial disclosures.