Cardiac Troponin Values in Patients With Acute Coronary Syndrome and Sleep Apnea

Abstract

The results of this study suggest that OSA has a protective effect in the context of myocardial infarction and that patients with OSA may experience less severe myocardial injury. The possible role of OSA in cardioprotection should be explored in future studies.

Does OSA Upregulate Cardioprotective Pathways to an Ischemic Insult?

“…The association between OSA severity and peak cTn-I or area under the cTn-I curve was not statistically significant but showed a trend toward lower cTnI with increasing OSA severity. 11 Thus, although IH of short duration and mild severity is typically linked to beneficial adaptive responses, 2 the current data suggest increasing cardiac protection with increasing IH severity, as previously shown for neuroprotection. 7 These data of Sánchez-de-la-Torre et al 11 are in agreement with the previous report by Shah et al 12 of lower peak troponin-T levels in patients with OSA with acute myocardial infarction.…”

“…11 Thus, although IH of short duration and mild severity is typically linked to beneficial adaptive responses, 2 the current data suggest increasing cardiac protection with increasing IH severity, as previously shown for neuroprotection. 7 These data of Sánchez-de-la-Torre et al 11 are in agreement with the previous report by Shah et al 12 of lower peak troponin-T levels in patients with OSA with acute myocardial infarction. By contrast, Buchner et al 13 (using contrast-enhanced MRI, which is widely accepted as the reference method for imaging infarct size) found greater final infarct size in patients with sleep-disordered breathing than in those without.…”

“…7 This paradigm shift in sleep apnea research is reinforced by the consistent lack of clinical benefit of CPAP therapy or adaptive servo-ventilation regarding the prevention of cardiovascular events in large clinical trials of patients with obstructive or central sleep apnea and established cardiovascular disease. [8][9][10] In this issue of CHEST, Sánchez-de-la-Torre et al 11 provide some preliminary evidence supporting the concept of OSA-induced cardioprotection. The authors prospectively studied 127 patients admitted to the hospital for an acute coronary syndrome.…”

Intermittent Hypoxia and Obstructive Sleep Apnea: Mechanisms, Interindividual Responses and Clinical Insights

“…For instance, peak cardiac troponin values were shown to be significantly higher in AMI patients without OSA than in AMI patients with OSA. This finding suggests that OSA might have a protective effect in the context of MI and that patients with OSA may experience less severe myocardial injury [16]. Additionally, the prevalence of non-ST-elevation myocardial infarction (NSTEMI) in AMI patients was associated with OSA and was shown to increase with the increasing severity of OSA.…”

“…The severity of the IH and the hypoxemia in OSA are determined by the number of the hypoxic events per hour of sleep, termed Apnea-Hypopnea Index (AHI). It mostly ranges from a cutoff point of 10 events per hour of sleep for normal breathing to mild (11)(12)(13)(14)(15)(16)(17)(18)(19)(20), moderate (21)(22)(23)(24)(25)(26)(27)(28)(29)(30), and severe OSA (>30 events per hour of sleep). In severe patients, blood oxygenation levels can intermittently drop to as low as 60%.…”