Impaired brachial flow-mediated dilation (FMD) is associated with risk for subsequent cardiovascular events in patients after myocardial infarction (MI). These patients often have obstructive sleep apnea (OSA). We tested the hypothesis that patients with OSA post MI will exhibit more severe impairment in FMD.

The researchers studied 64 patients with MI admitted to our hospital. Obstructive sleep apnea was determined using polysomnography. FMD was measured using high-resolution ultrasonography, with researchers blind to the obstructive sleep apnea (OSA) diagnosis.

The mean age was 60 ± 11 years, and the mean BMI was 29 (26, 32 kg/m2), 84% of patients were men, 39% had moderate to severe OSA (apnea-hypopnea index [AHI] > 15), and 31% of the patients had  mild OSA (5 ? AHI < 15). FMD was severely impaired in patients with moderate to severe OSA (0.8% ± 0.7%) as compared with patients without OSA (4.7% ± 0.8%, P = .001) and with mild OSA (3.9% ± 0.8%, P = .015). Linear regression showed that FMD was associated with log nocturnal nadir oxygen saturation (minSao2) (? = 31.17, P = .0001), age (? = ?0.11, P = .006). MinSao2 was an independent predictor of FMD after adjustment for possible confounders (? = 26.15, P = .001).

FMD is severely impaired in patients with moderate to severe OSA post MI, which may be partially related to nocturnal hypoxemia. Patients with  obstructive sleep apnea may, therefore, be at higher risk for subsequent cardiovascular events after an MI. Identifying and treating   obstructive sleep apnea may have important implications in the long-term prognosis of patients post MI. Further studies are necessary to determine if the presence of OSA would affect the long-term occurrence of cardiovascular events after an MI.

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Filed under: Cardiovascular DiseaseClinical ResearchHeart AttackHeart ProblemsObstructive Sleep ApneaOther DisordersSleepSleep ApneaSleep Apnea EffectsSleep Apnea NewsSleep Apnea ResearchSleep Apnea StudySleep Problems

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