Impact of Sleep-Disordered Breathing on Myocardial Salvage and Infarct Size in Patients With Acute Myocardial Infarction
Does sleep disordered breathing (SDB) impact infarct size 3 months after myocardial infarction (MI)?
This was a prospective observational study performed at a single hospital in Germany. All patients underwent cardiovascular magnetic resonance (CMR) to define salvaged myocardium and infarct size within 3-5 days and at 3 months after acute MI. Patients were stratified according to apnea–hypopnea index (AHI) assessed by polysomnography at baseline into those with (AHI ≥15/hour) and without (AHI <15/hour) SDB.
A total of 220 consecutive patients with first MI and percutaneous coronary intervention (PCI) were screened between March 2009 and June 2011. After exclusions (shock, unable to follow-up, need for surgery, severe medical illnesses, lack of consent, no sleep study or CMR), 56 patients were enrolled. SDB was found in 29 (52%) and not in 27 patients. There was no significant difference between the SDB and no SDB groups with respect to age, gender, coronary risk factors, and hemodynamic findings. Patients with SDB had higher body mass index and left ventricular mass compared with no SDB. There were no significant differences for time from symptom onset to revascularization, infarct-related artery, TIMI flow pre- or post-PCI, thrombus aspiration, or use of glycoprotein IIb/IIIa inhibitors during PCI. All patients were on optimal medical therapy. One patient without SBD had recurrent MI during follow-up.The area at risk between both groups was similar (40 ± 12% vs. 40 ± 14%, p = 0.925). Patients with SDB had significantly less salvaged myocardium (myocardial salvage index 52% vs. 77%, p < 0.001), smaller reduction in infarct size (0.3% vs. 6.5%, p < 0.001) within 3 months after acute MI, a larger final infarct size (23% vs. 12%, p < 0.001), and a lower final left ventricular ejection fraction (48% vs. 54%, p = 0.023). In a multivariate analysis, including established risk factors for large MI, AHI was independently associated with less myocardial salvage and a larger infarct size 3 months after acute MI.
The authors concluded that SDB was associated with less myocardial salvage and a smaller reduction in infarct size.
These findings suggest a contribution of SDB to impaired healing of MI. Reducing infarct size is an important goal in treating patients with acute MI. The next steps would be to test whether diagnosis and treatment of SDB early after MI would reduce infarct size at 3 months.
Keywords: Myocardial Infarction, Follow-Up Studies, Multivariate Analysis, Ventricular Function, Left, Risk Factors, Germany, Sleep Apnea Syndromes, Percutaneous Coronary Intervention, Body Mass Index, Polysomnography, Thrombosis, Salvage Therapy, Cardiovascular Diseases, Stroke Volume, Magnetic Resonance Spectroscopy
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