Updated guidelines on cardiovascular evaluation before noncardiac surgery: A view from the trenches

IMPACT ON CLINICAL PRACTICE: A PERIOPERATIVE HOSPITALIST'S VIEW

Regarding testing

Although the updated guidelines provide some novel concepts in risk stratification, the new algorithm still leaves many patients in a gray zone with respect to noninvasive testing. Patients with heart failure, valvular heart disease, and arrhythmias appear to be somewhat disconnected from the algorithm in this version, and management according to clinical practice guidelines is recommended.

Patients with acute coronary syndrome remain embedded in the algorithm, with recommendations for cardiology evaluation and management according to standard guidelines before proceeding to elective surgery.

The concept of a combined risk based on clinical factors along with the surgical procedure is important, and an alternative to the RCRI factors is offered. However, while this new NSQIP surgical risk calculator is more comprehensive, it may be too time-consuming for routine clinical use and still needs to be externally validated.

There is only limited evidence as to how arrhythmias affect surgical risk

The concept of shared decision-making and team communication is stressed, but the physician may still have difficulty deciding when further testing may influence management. The guidelines remain somewhat vague, and many physicians may be uncomfortable and will continue to look for further guidance in this area.

Without more specific recommendations, this uncertainty may result in more stress tests being ordered—often inappropriately, as they rarely change management. Future prospective studies using biomarkers in conjunction with risk calculators may shed some light on this decision.

The new perioperative guidelines incorporate other ACC/AHA guidelines for valvular heart disease¹⁵ and heart failure.¹⁴ Some of their recommendations, in my opinion, may lead to excessive testing (eg, repeat echocardiograms) that will not change perioperative management.

Regarding revascularization

The ACC/AHA guidelines continue to emphasize the important concept that coronary revascularization is rarely indicated just to get the patient through surgery.

The new guidelines give physicians some leeway in allowing patients with drug-eluting stents to undergo surgery after 6 rather than 12 months of dual antiplatelet therapy if they believe that delaying surgery would place the patient at more risk than that of stent thrombosis. There is evidence in the nonsurgical setting that the newer stents currently being used may require no more than 6 months of therapy. In my opinion it was never clear that there was a statistically significant benefit in delaying surgery more than 6 months after placement of a drug-eluting stent, so this is a welcome addition.

Regarding beta-blockers

The systematic review of beta-blockers reinforces the importance of continuing them preoperatively while downgrading recommendations for their prophylactic use in patients who are not at increased risk.

Although the debate continues, there is no doubt that beta-blockers are associated with a decrease in myocardial ischemia and infarction but an increase in bradycardia and hypotension. They probably are associated with some increased risk of stroke, although this may be related to the specific beta-blocker used as well as the time of initiation before surgery. Evidence of a possible effect on mortality depends on whether the DECREASE and POISE trials are included or excluded in the analysis.

In the absence of new large-scale randomized controlled trials, we are forced to rely on observational trials and expert opinion in the meantime. I think that if a beta-blocker is to be started preoperatively, it should be done at least 1 week before surgery, and a more cardioselective beta-blocker should be used.

Regarding other drugs and tests

I agree with the recommendation to continue ACE inhibitors and ARBs preoperatively in patients with heart failure and poorly controlled hypertension. Although somewhat contrary to current practice, continuance of these drugs has not been associated with an increase in myocardial infarction or death despite concern about intraoperative hypotension.

Data from randomized controlled trials of perioperative statins are limited, but the information from observational studies is favorable, and I see little downside to initiating statins preoperatively in patients who otherwise have indications for their use, particularly if undergoing vascular or other high-risk noncardiac surgery. It is not known whether the specific drug, dose, or timing of initiation of statins influences outcome.

Although multiple studies of biomarkers suggest that there is an association with outcome, there are no randomized controlled trials or specific interventions shown to improve outcome.

Some of the recommended interventions have included various cardiac medications, stress testing, possible coronary angiography, and revascularization, which are not without risk. In the absence of data and following the directive to "first do no harm," the ACC/AHA has been appropriately cautious in not recommending them for routine use at this time.

The updated guidelines have summarized the new evidence in perioperative cardiac evaluation and management. Many of their recommendations were reinforced by this information and remain essentially unchanged. Several new recommendations will lead to changes in management going forward. Unfortunately, we lack the evidence to answer many questions that arise in routine practice and are therefore forced to rely on expert opinion and our clinical judgment in these cases. The ACC/AHA guidelines do provide a framework for our evaluation and management and help keep clinicians up-to-date with the latest evidence.