Unrecognized severe OSA is a major risk factor for postoperative cardiovascular events, according to the authors of new research.1,2

“We found that patients with severe apnea, within the first week and first 30 days after surgery, had much higher rates of cardiovascular outcomes,” says Dennis Auckley, MD, professor of medicine at Case Western Reserve University in Cleveland.

Researchers found that patients with severe OSA had double the risk of an adverse cardiac event, such as heart failure, stroke, myocardial injury, and cardiac death, occurring within 30 days after surgery. Within 30 days of surgery, 235 patients experienced cardiac problems. Of those 235 patients, 17 died from a cardiac cause, and 205 sustained a myocardial injury. Congestive heart failure affected 1.7% of patients. Less commonly, some patients experienced thromboembolism and stroke.1

Auckley notes these findings show why it is important for surgery center staff to note OSA risk and develop policies and procedures to prevent cardiovascular problems among patients at risk for the condition. For instance, Auckley suggests performing shorter surgeries with less anesthesia and fewer opioids. Patients at risk of severe OSA should be observed, especially if there are underlying comorbidities and opioids are used to manage pain after surgery.

“The other thing surgery centers can do is monitor patients closely in the PACU,” Auckley explains. “If they have ongoing saturation events or are slow in their respiratory rate, then they might be at risk of problems post-surgery.” Most patients in the study received nocturnal oximetry monitoring immediately after surgery.1

Another strategy is to perform the high-risk OSA patient’s surgery earlier in the day so he or she can be watched longer in the PACU or to keep the patient in observation overnight, Auckley adds. About 68% of patients had unrecognized OSA, and 11.2% of patients had severe OSA. Also, three in five patients had two risk factors for cardiac disease. When these patients underwent intraperitoneal and major orthopedic surgical procedures, about 42% of the procedures were for cancer.1

Patients were screened with the STOP-BANG risk score questionnaire. (See cover story for more information about the tool.) About 26% of patients were rated as high risk, and 53% were rated as intermediate risk, with close to 21% rated as low risk.2 Both high-risk and intermediate-risk patients were significantly associated with readmission to an ICU.1

“These are patients undergoing a variety of noncardiac surgeries, the majority of which were a mix of orthopedic, intraperitoneal, and vascular surgeries,” Auckley adds.

The patients had comorbidities, were 45 years of age and older (with 42.1% in the 65 to 74 years of age range), and about 60% of the patients were men.2 OSA patients also were more likely to undergo unplanned tracheal intubation or postoperative lung ventilation. Patients with myocardial injury had ischemic symptoms, changes in ECG or cardiac imaging, and fulfilled the diagnosis of myocardial infarction.2 The study, which included 1,218 adult patients from five countries observed between January 2012 and July 2017, revealed that a cohort without OSA demonstrated a 0.3% death rate. Conversely, the group with OSA demonstrated a 4.4% death rate.2 The percentage of patients who sustained cardiac injury or died increased with the severity of OSA.

For instance, about 14% of those without OSA experienced a cardiac event. This rate increased to 19% for those with mild OSA, 22% for patients with moderate OSA, and 30% for patients with severe OSA.2 These findings should be a wake-up call about the importance of surgery centers and physicians screening patients for potential OSA.

“This should raise awareness that this is a major issue,” Auckley says. “Patients with severe obstructive sleep apnea are at risk of cardiac issues.”

Surgery centers need to screen for OSA, as most of these conditions are undiagnosed, and they should be well educated on optimal interventions. “There are common sense interventions, including closely monitoring these patients,” Auckley adds. Limited opioid use, elevating patients after surgery, and even referring some severely at-risk patients to an inpatient surgical setting also are tactics to employ. Physicians and surgery centers sometimes become aware of the dangers OSA poses after a patient has died or become injured because of the problem, but that is too late.

“Most centers get interested when they have a bad outcome and the lawyers come,” Auckley says. “Almost 20 years ago, soon after I started practicing, we had a bad outcome, and formed a committee to look into this issue, which is why we have had an algorithm for managing these patients for quite a while.”

REFERENCES

  1. Chan MTV, et al. Association of unrecognized obstructive sleep apnea with postoperative cardiovascular events in patients undergoing major noncardiac surgery. JAMA 2019;321:1788-1798.
  2. Auckley D, Memtsoudis S. Unrecognized obstructive sleep apnea and postoperative cardiovascular complications: A wake-up call. JAMA 2019;321:1774-1776.