Perioperative debates

Published in the April 2018 issue of Today’s Hospitalist

RECENT GUIDELINES are helping settle some longstanding perioperative controversies, according to hospitalist Hugo Quinny Cheng, MD, director of the medicine consultation service at the University of California, San Francisco (UCSF) Medical Center.

Speaking at UCSFs management of the hospitalized patient conference last fall, Dr. Cheng presented new evidence on how long to delay surgery after stenting, the need to bridge (or not) surgical patients on anticoagulation, and how to medically manage patients headed to surgery who have cardiac disease. He also weighed in on two other hot topics: perioperative management of patients with suspected obstructive sleep apnea and how to minimize opiate prescribing in surgical patients.

CASE 1
Stents and surgical delays
A 63-year-old patient who needs a hemicolectomy for colon cancer had a drug-eluting stent placed four months ago. Do you OK the surgeon to proceed, wait six months post-stent to do the surgery or wait 12 months?

“If delaying surgery would cause undue harm, waiting only three months after stent implant is what guidelines call ‘not unreasonable.’ “

~ Hugo Quinny Cheng, MD
University of California, San Francisco Medical Center

In terms of stent type and timing and how those relate to postop cardiac complications, a retrospective analysis in the Oct. 9, 2013, Journal of the American Medical Association looked at more than 25,000 patients who had noncardiac surgery between six weeks and two years after receiving either a bare-metal or a drug-eluting stent. Researchers tracked cardiac complication rates including all-cause mortality, myocardial infarction and the need for revascularization.

“For both stent types, bad outcomes happened at an alarmingly high rate with surgery soon after the implant,” said Dr. Cheng. But complication rates declined fairly rapidly and reached their nadir by 180 days. ACC/ AHA guidelines published in the March 29, 2016, issue of Circulation recommend waiting 30 days for surgery after a bare-metal stent and six months after a drug-eluting stent.

“But the guidelines also say that if delaying surgery would cause undue harm, waiting only three months after stent implant is what they call ‘not unreasonable,’ ” Dr. Cheng pointed out. As for the case he presented,
“I would say the patient should go to the OR now.”

What about DAPT?
The question then becomes what to do with the patient’s dual antiplatelet therapy. The 2016 guidelines say that if you must stop a patient’s P2Y12 inhibitor, continue aspirin if possible, then resume the P2Y12 postop as soon as possible.

“You’re looking at this and saying, ‘Is this about the most wishy-washy thing they could say?’ ” But Dr. Cheng noted that there isn’t a lot of evidence backing up any particular strategy. Instead, there are small case series, a case-control study and expert opinion.

“It’s fine to listen to the cardiologists,” he said. “But realize that when they are adamant that a patient has to stay on these drugs and the surgeon is saying ‘No, I’m worried about bleeds,’ the cardiologists don’t have a stack of randomized controlled trials to tell them that this is the right way to go.”

CASE 2
Bridging anticoagulated patients
In Dr. Cheng’s next case, a 76-year-old woman with paroxysmal A fib on warfarin underwent head and neck surgery two days ago. Her CHA2DS2- VASc score is 5 (her CHADS2 score is 3), her hemoglobin is 8 and her platelet count is 88,000.

Her surgeon asks if the patient should be bridged with either IV heparin or low-molecular-weight heparin. Do you bridge or not?

For years, Dr. Cheng said, clinicians have been moving away from bridging perioperative patients on warfarin with heparin. But “now,” he said, “recent guidelines based on the latest evidence actually back up that decision.”

That evidence comes from the BRIDGE trial, with results published online by the New England Journal of Medicine (NEJM) in June 2015. The study randomized nearly 1,900 surgical patients—all on warfarin for A fib with flutter—to either bridging with low-molecular-weight heparin or placebo. Patients undergoing cardiac or neurological surgeries were excluded, as were those with mechanical valves. Outcomes were 30-day risk of arterial thromboembolism and bleeding.

As Dr. Cheng explained, patients had the same number of embolic events whether or not they were bridged. However, “bleeding increased in bridged patients, about 3% vs. 1%, and the number needed to harm to cause one major bleed was 53.” As for minor bleeding, bridging numbers were even worse: 21% vs. 12%, with one minor bleed for every 12 patients bridged.

But, he noted, very few enrollees in that trial had high CHADS2 scores. Instead, “the average was about 2.3.”

Balancing clotting and bleeding risk
In the Feb. 21, 2017, Journal of the American College of Cardiology, the ACC published expert consensus on how to manage perioperative anticoagulation among A fib patients.

Among its general recommendations: Clinicians can perform some procedures—those with negligible bleeding, like cataract surgery—on patients with full anticoagulation. And bridging isn’t necessary for patients taking direct oral anticoagulants because of those drugs’ rapid onset.

As for patients on warfarin, the guideline says to base bridging decisions on both clotting and bleeding risk. The guidelines define elevated bleeding risk as having had a major bleed or intracranial hemorrhage within the last three months, low or abnormal platelets, aspirin use, a supratherapeutic INR, or prior bleeding with bridging or similar surgery.

The guidelines also recommend using the CHA2DS2VASc score to assess clotting risk. Patients scoring between 1 and 4 are considered low risk, while moderate risk is 5 or 6, and high risk is between 7 and 9. According to the guidance, patients should be bridged if their CHA2DS2-VASc score indicates high risk and they have normal bleeding risk. However, for those with a high-risk score and elevated bleeding risk, doctors should use clinical judgment.

As for the case he presented with a CHA2DS2VASc score of 5, the guidance recommends using clinical judgment when such patients have normal bleeding risk. But “the patient had a low platelet count, so a high bleeding risk,” Dr. Cheng pointed out. “The guidelines recommend not bridging that patient.”

CASE 3
Preventing postop ischemia and MIs
You do a preop evaluation on a patient who’s scheduled for a femoral- popliteal arterial bypass next week. The patient smokes and has diabetes and peripheral arterial disease, but the only medication he takes is glyburide. What should you do now: start aspirin, metoprolol or atorvastatin?

Among those choices, more than a quarter (27%) of the hospitalist audience picked starting metoprolol. Dr. Cheng noted that in the past, beta-blockers have had “the most enthusiasm for preventing cardiac complications after surgery.”

But some studies behind that enthusiasm have since been discredited, he added. “The largest study found only a small benefit on MI prevention, while overall mortality increased.” As a result, “beta-blockers have largely fallen out of favor,” and 2014 ACC/ AHA guidelines on periop cardiovascular evaluation and management of patients undergoing noncardiac surgery recommend beta-blockers strongly only if patients already take them.

Those guidelines, published online in August 2014 by the Journal of the American College of Cardiology, do note that it would “not be unreasonable”—”Guidelines are really good at hedging bets!” Dr. Cheng said—to start patients on a beta-blocker if they have a revised cardiac risk index score of 3 or more or if patients have ischemia on a preop stress test.

But not if patients need urgent or emergent surgery. “With beta-blockers, you want to start low, go slow and begin way in advance of any planned surgery,” Dr. Cheng said.

The case for statins
As for aspirin, the POISE trial published in the April 17, 2014, NEJM randomized patients at high risk for complications before surgery to aspirin, the antihypertensive clonidine, both or neither. Aspirin did not prevent death or MI, but it (not surprisingly) increased bleeding complications. Clonidine likewise didn’t prevent MI or death but—again, no surprise—it was linked to clinically significant hypotension and bradycardia.

The 2014 ACC/AHA guidelines don’t recommend starting aspirin in patients undergoing noncardiac surgery unless they have a stent, nor do they recommend starting alpha-2 agonists like clonidine. The guidelines also don’t endorse preop coronary revascularization, except for independent guideline-concordant indications.

As for starting statins, research in the Sept. 3, 2009, NEJM looked at 500 statin-naive patients undergoing major vascular surgery. Those patients were randomized one month before surgery to either fluva-statin XL or placebo.

“Patients on statins were roughly half as likely to develop cardiac death or nonfatal MI,” said Dr. Cheng. “Almost all that difference was in nonfatal MI, so mortality didn’t differ very much at all.”

A more recent analysis published in the February 2017 JAMA Internal Medicine looked at 180,000 VA patients undergoing noncardiac surgery. Researchers looked at early statin treatment—defined as getting a statin on postop day 0 or 1—and postop mortality and complications. The results: Early statins were associated with lower all- cause 30-day mortality, fewer cardiac complications, and fewer total complications, including respiratory problems and renal insufficiency.

The authors also found a dose effect, with patients who received moderate- or high-intensive statins experiencing better outcomes than those with lower doses.

“It’s a retrospective study,” Dr. Cheng said, “so obviously there’s the potential for a lot of confounders.”

The 2014 ACC/AHA guidelines recommend continuing patients already on statins and starting patients going for vascular surgery on a statin, regardless of their cholesterol levels. The guidelines also bring out the “it’s-not-unreasonable” rationale to initiate statins in patients with elevated clinical risk based on your preop assessment and for those undergoing moderate- or high-risk operations.

Edward Doyle is Editor of Today’s Hospitalist.

Surgery and sleep apnea
A 55-YEAR-OLD morbidly obese patient with hypertension is scheduled for total knee replacement. He reports occasional fatigue and somnolence, but he doesn’t know if he snores or has apnea. Should you notify the surgical team of suspected obstructive sleep apnea (OSA), or first notify the surgical team and then recommend empiric CPAP postop? Or should you delay surgery until the patient has a formal sleep study?

Hugo Quinny Cheng, MD, director of the medicine consultation service at the University of California, San Francisco (UCSF) Medical Center, presented this case during UCSF’s management of the hospitalized patient conference last fall. According to Dr. Cheng, sleep apnea “probably” increases patients’ risk of postop complications.

Guidelines published in August 2016 by Anesthesia and Analgesia found that patients with OSA are more likely to develop postop pulmonary complications such as respiratory failure. Evidence also suggests an association between OSA and higher risk of postop A fib.

As for screening patients, the guidelines recommend using STOPBANG, the acronym for Snoring, Tired or sleepy, Observe apnea, Pressure (hypertension), BMI greater than 35, Age greater than 50, Neck circumference of more than 17 inches for men or 16 for women, and Gender being male.

This “quick-and-dirty assessment has a positive predictive value of close to 90%” among patients scoring five or more points, Dr. Cheng said. “A sleep study will help confirm the diagnosis, but I don’t think you need that additional degree of certainty.”

The guidelines agree, noting that there’s not enough evidence to recommend delaying surgery for a formal sleep study as the standard of care. Exceptions include evidence of severe or uncontrolled systemic OSA complications or impaired gas exchange, such as known severe pulmonary hypertension, hypoventilation or resting hypoxia.

And while the guidelines do say to notify both the surgeon and the anesthesiologist about suspected sleep apnea, “there is no randomized trial that consistently shows that putting OSA patients on CPAP or BIPAP after surgery leads to better outcomes,” Dr. Cheng said.

Pay attention to opiate prescribing
WHILE OPIATE OVERUSE for chronic non-cancer pain has received a lot of coverage, “very little attention has been paid to opiates used to treat postop pain,” said Hugo Quinny Cheng, MD, director of the medicine consultation service at the University of California, San Francisco Medical Center, during a presentation last year on perioperative controversies. “But maybe there should be.” With 100 million operations performed in this country every year, “the potential pool of patients being exposed to that risk is enormous.”

A study published online in April 2017 by JAMA Surgery tried to gauge patients’ risk of developing persistent postop use by looking at 36,000 patients undergoing one of 13 common surgeries. One big problem with the results: “Most were minor surgeries,” Dr. Cheng pointed out. “The authors excluded orthopedic or spine surgery patients—the pain surgery patients.”

Overall, the incidence of persistent opiate use more than 90 days after surgery was 6%, “and it was the same whether patients were getting a colectomy or hernia repair,” he said. Risk factors for developing chronic use were a history of alcohol, tobacco, or other drug use, sicker patients with more baseline comorbidities, and those with psychiatric comorbidity or pain unrelated to their surgery.

“There is,” Dr. Cheng said, “a significant risk that such patients may develop persistent opiate abuse after they go home.”