Parsing periop predicaments

Due to a lack of evidence for best perioperative procedures, clinicians have debated for decades how to address circumstances such as stroke or atrial fibrillation.

Common problems without good evidence-based solutions include the timing of elective surgery after stroke and medication management before noncardiac surgery in patients with atrial fibrillation and a stent. Since definitive data don't exist to guide us in these scenarios, we often rely on "clinical pearls."

The timing of elective noncardiac surgery after ischemic stroke is something for which there was essentially no evidence for a number of years, and we winged it. Now we have some limited evidence, but I'm not sure physicians are aware of it. For most patients who have had an ischemic stroke, it's reasonable to perform elective noncardiac surgery three months after the stroke instead of waiting six to nine months as previously recommended.

Dr. Cohn discusses perioperative practices for cardiological conditions. (Duration 1:46)

In 2014, a study published in JAMA looked at a large registry of more than 470,000 Danish patients without a history of stroke and 7,100 patients who had a stroke who underwent noncardiac surgery. The study looked at the time elapsed after the stroke and when patients had surgery and the incidence of a recurrent ischemic stroke, major adverse cardiac events, and mortality. Patients who had surgery within one month of a stroke had the highest incidence of adverse events. It was still high from one to three months postsurgery, decreased a bit from three to six months, but persisted at an elevated rate up until nine months when it stabilized. The study recommended to wait at least nine months after a stroke before doing elective surgery, which seemed a bit excessive to me. I don't know that many clinicians were actually following that recommendation.

In 2020, the Society for Neuroscience in Anesthesiology and Critical Care recommended waiting at least nine months based on that single 2014 study. That recommendation was followed in the same year by a scientific statement from the American Heart Association (AHA)/American Stroke Association (ASA), which said that although the evidence is limited, we would recommend that patients wait at least six months after a stroke before undergoing elective noncardiac surgery.

The following year, a study published in JAMA Surgery (by two of the authors of the AHA/ASA statement) looked at a large database of almost 6 million Medicare patients, 54,000 or so of whom had had a stroke. It was a much larger, older group, with more comorbidities than the Danish study. It found that the incidence of recurrent ischemic stroke or mortality was highest with surgery in the first month after the stroke, decreased between one and three months, but after three months, leveled off. In contrast to the Danish study, where researchers said to wait six to nine months before performing noncardiac surgery, this study found that the time frame was really much shorter, only three months. Their conclusion was that the AHA/ASA statement was maybe a bit too conservative in recommending waiting six months or more. That supported what we were already doing at the University of Miami, which was to wait three months.

The second pearl involves another scenario that we have zero evidence for but will be seeing a lot more in the future: patients who have atrial fibrillation (AF), coronary artery disease, and a stent. These patients used to be on triple therapy (anticoagulant and dual antiplatelet therapy [DAPT]), and then it became double therapy (anticoagulant and aspirin or P2Y12 inhibitor); now the newest recommendations are for single therapy (anticoagulant) after a year. So, how do we manage a patient who has AF and coronary artery disease, who has undergone percutaneous coronary intervention (PCI) with placement of a drug-eluting stent more than a year ago, is now on anticoagulant monotherapy, and has to undergo noncardiac surgery?

I am not aware of any studies or information other than theoretical choices and views of some experts I spoke with. We know that somebody with AF who has a CHA2DS2-VASc score indicating an elevated thromboembolic risk is going to be on some form of anticoagulation, either warfarin or a direct oral anticoagulant (DOAC). We also know that patients who have stents are going to be on DAPT initially for some period of time, after which one of the drugs will be stopped. When they go to surgery, we usually recommend that they continue antiplatelet therapy, typically aspirin.

The guidelines for AF have changed, because patients with AF and PCI were previously treated with aspirin, a P2Y12 inhibitor, and an oral anticoagulant—so-called triple therapy—which was associated with an increased risk of bleeding. The most recent guidelines suggest that after one year of antiplatelet therapy (initially DAPT, then a single drug) plus an anticoagulant, patients should drop the antiplatelet therapy completely and just continue their anticoagulant. The duration of DAPT has changed, getting shorter and shorter over time, and recently the trend is changing to continue the P2Y12 inhibitor rather than aspirin as the antiplatelet agent.

The problem now is, when a patient on anticoagulant monotherapy goes to surgery, you have to stop the oral anticoagulant, and the patient no longer has any protection against stent thrombosis. A substudy of the Perioperative Ischemic Evaluation 2 (POISE-2) trial showed that patients who had PCI, regardless of type of stent, did better if they continued aspirin as opposed to stopping aspirin perioperatively. There was a 50% relative risk reduction and a 5% absolute risk reduction in nonfatal myocardial infarction in these patients, and they showed no increased risk of bleeding with the surgery. The recommendation based on the substudy was that anybody who had a stent should try to continue antiplatelet therapy perioperatively. So, should we start an aspirin in patients with a stent who have been on anticoagulant monotherapy or not?

Warfarin is typically stopped five days before surgery and restarted postop, but is not therapeutic for at least another five days, meaning you have almost 10 days where the patient has no stent protection. I asked a number of anticoagulation and cardiology experts what they would do in this scenario. Nine of the 10 physicians I asked said they would start aspirin, which seems reasonable to me. Although we have no evidence and no clinical studies, this is something we will be seeing much more of in the near future as people go from triple therapy to double therapy to anticoagulant monotherapy.

Now, what would we do with patients on a DOAC instead, for example, because in this case you'd only have to stop the drug for a day or two before surgery, and you can restart it one to three days after surgery. The time frame that patients would be without anticoagulation, without protection for their stent, would be much shorter, maybe three to five days. In that case, I'm not convinced that I would use aspirin. But if it's going to be a seven- to 10-day period or longer, as with warfarin, I think starting aspirin is reasonable.