Undiagnosed Sleep Apnea and Bypass OperaTion

The SABOT Study is an observational study designed to study the impact of sleep apnea on cardiovascular outcomes after non-urgent coronary artery bypass surgery (CABG). Patients between the ages of 18 and 90 who are scheduled undergo an non-urgent CABG were eligible for the study

The recruited patients participants were scheduled to undergo a hospital-based overnight sleep study using a US Food and Drug Administration-approved portable monitoring devices: the Watch-PAT (Itamar Medical, Caesarea, Israel). Watch-PAT is a four-channel unattended sleep monitoring device that measures peripheral arterial tone (PAT), pulse oximetry, heart rate, and actigraphy from a built-in actigraph. Respiratory events are identified by digital vasoconstriction mediated by α-adrenergic receptors that are sensitive to surges in sympathetic activity. Respiratory events are considered to be present when one of the following three criteria was met: a reduction in PAT amplitude with an acceleration of the pulse rate or an increase in wrist activity; a reduction in PAT amplitude with ≥3% oxyhemoglobin desaturation; and ≥4% oxyhemoglobin desaturation only. Although manual scoring and editing of the Watch-PAT signals are possible, we adopted results generated by the device algorithm alone with no intervention by the operator. The diagnosis of sleep apnea is confirmed if the AHI was greater than 15 events/h.

End Points The pre-specified primary end point is a major adverse cardiac and cerebrovascular event (MACCE), defined as a composite of cardiovascular mortality, non-fatal myocardial infarction, non-fatal stroke, and repeat revascularization.

The secondary end point comprised sudden cardiac death or resuscitated cardiac arrest, all-cause mortality, and hospitalization for heart failure.

Inclusion criteria

• Patients with coronary artery disease scheduled to undergo non-urgent coronary artery bypass surgery

Exclusion criteria

• Known sleep apnea on CPAP therapy
• Cardiogenic shock on mechanical hemodynamic support
• Intubated on mechanical ventilation
• Heart failure on oxygen therapy
• Long -term alpha blocker therapy
• Severe chronic pulmonary disease
• Recurrent malignant arrhythmia
• Inability to provide informed consent