Intrinsic Cardiac Risk of Inspire Surgery
Inspire surgery (upper airway stimulation for obstructive sleep apnea) should be classified as low intrinsic cardiac risk, with an estimated 30-day cardiac event rate of less than 1%. 1
Risk Classification Framework
The European Society of Cardiology and ACC/AHA guidelines stratify surgical procedures into three cardiac risk categories based on 30-day rates of cardiac death and myocardial infarction 1:
- Low-risk surgery: <1% cardiac event rate (includes endoscopic procedures, superficial procedures, cataract surgery, breast surgery, ambulatory surgery) 1
- Intermediate-risk surgery: 1-5% cardiac event rate (includes intraperitoneal/intrathoracic surgery, carotid endarterectomy, head and neck surgery, orthopedic surgery, prostate surgery) 1
- High-risk surgery: ≥5% cardiac event rate (includes aortic and major vascular surgery, peripheral vascular surgery, emergent major operations with large fluid shifts/blood loss) 1
Why Inspire Surgery is Low-Risk
Inspire surgery falls into the low-risk category because it shares characteristics with other head and neck procedures that involve minimal hemodynamic stress, limited tissue trauma, and no significant fluid shifts or blood loss. 1
The intrinsic cardiac risk of operations depends on several surgery-specific factors 1, 2:
- Magnitude and duration: Inspire implantation is a relatively brief procedure with limited surgical dissection 1
- Hemodynamic stress: Minimal alterations in heart rate, blood pressure, vascular volume, and neurohumoral activation 1
- Fluid shifts and blood loss: Negligible compared to intermediate or high-risk procedures 1
- Tissue injury: Limited surgical trauma reduces the stress response that increases myocardial oxygen demand 1
Clinical Implications for Preoperative Assessment
For low-risk procedures like Inspire surgery, extensive preoperative cardiac testing is rarely indicated, even in patients with known cardiac disease. 1, 3
The preoperative approach should focus on 1, 3:
- Identifying active cardiac conditions (unstable coronary syndromes, decompensated heart failure, significant arrhythmias, severe valvular disease) that would require optimization regardless of surgery 1
- Assessing functional capacity: Patients who can climb 2 flights of stairs (≥4 METs) generally do not require further cardiac testing for low-risk surgery 1, 3
- Continuing chronic cardiac medications: Statins and beta-blockers should be continued in patients already taking them, but routine initiation of high-dose beta-blockers is not recommended 3
Important Caveats
The low intrinsic cardiac risk of the procedure does not eliminate patient-specific risk factors. 1, 2 Individual patient characteristics (history of myocardial infarction, heart failure, diabetes requiring insulin, renal dysfunction, cerebrovascular disease) still contribute to overall perioperative cardiac risk through the Lee index or similar risk stratification tools 1.
However, the combination of low surgical risk with even multiple patient risk factors typically results in acceptable overall perioperative cardiac risk that does not require delay or extensive preoperative cardiac workup. 1, 3