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2019 Update in perioperative cardiovascular medicine

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Release date: October 1, 2019
Expiration date: September 30, 2020
Estimated time of completion: 1 hour

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ABSTRACT

We performed a MEDLINE search and found 6 studies published February 2018 through January 2019 that should influence perioperative cardiovascular medicine, specifically in preoperative cardiac risk assessment, perioperative medication management, and postoperative cardiac complications.

KEY POINTS

  • The Duke Activity Status Index is a better tool for assessing cardiopulmonary fitness than subjective assessment, and it should be considered for use in guideline algorithms.
  • Aspirin should not be given perioperatively in patients undergoing vascular surgery other than carotid endarterectomy.
  • Angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) are associated with intraoperative hypotension if given before surgery. Further study is needed to determined how best to manage ACE inhibitors and ARBs perioperatively.
  • In a study, dabigatran given to patients with myocardial injury after noncardiac surgery lowered the risk of major vascular complications, with no significant increase in major bleeding. But the study had major limitations.
  • Postoperative atrial fibrillation is associated with outcomes similar to those of nonsurgical nonvalvular atrial fibrillation. Anticoagulation decreases its stroke and mortality risk.


 

References

Perioperative medicine is an evolving field with a rapidly growing body of literature, particularly in cardiology.

In this update, we review 6 articles to answer questions related to preoperative cardiac risk assessment, perioperative medication management, and postoperative cardiac complications. We surveyed perioperative literature from February 2018 through January 2019 and chose the final articles by consensus, based on relevance to clinicians who provide preoperative evaluations and postoperative care to surgical patients.

These summaries are derived from “Updates in Perioperative Medicine” presented at the 14th Annual Perioperative Medicine Summit (Orlando, FL, February 13–16, 2019) and the 2019 Society of Hospital Medicine Annual Meeting (National Harbor, MD, March 24–27, 2019).

PREOPERATIVE CARDIAC EVALUATION

How well do measures of functional capacity predict perioperative complications and mortality in noncardiac surgical patients?

Functional capacity is commonly assessed in preoperative evaluations to estimate patients’ risks of perioperative complications and death. The American College of Cardiology/American Heart Association1 and the European Society of Cardiology2 guidelines both include estimation of cardiopulmonary fitness as a step in preoperative assessment before major noncardiac surgery.

“Subjective assessment” is one way to estimate functional capacity. Simply put, clinicians try to form a rough idea about the fitness of patients by asking questions about routine activities such as walking or climbing stairs. Although commonly used, subjective assessment of functional capacity lacks strong evidence that it predicts adverse perioperative events.

Table 1. The Duke Activity Status Index
The Duke Activity Status Index is another method: self-administered in a questionnaire, it consists of 12 questions, which have weighted values (Table 1).3 In its derivation and validation studies, its results were found to correlate with peak oxygen uptake during exercise.

Cardiopulmonary exercise testing is a third option. It measures peak oxygen consumption and anaerobic threshold during exercise. It is probably the best objective measurement of functional capacity, but not necessarily for predicting postoperative cardiac complications, and it is performed relatively infrequently.

[Wijeysundera DN, Pearse RM, Sulman MA, et al. Assessment of functional capacity before major non-cardiac surgery: an international, prospective cohort study. Lancet 2018; 391(10140):2631–2640. doi:10.1016/S0140-6736(18)31131-0]

In a multicenter, prospective cohort study, Wijeysundera et al4 compared subjective functional capacity assessment, the Duke Activity Status Index, cardiopulmonary exercise testing, and the preoperative N-terminal pro-B-type natriuretic peptide (NT-proBNP) level in their ability to predict complications and death in 1,401 noncardiac surgery patients older than 40 with at least 1 cardiovascular risk factor. After surgery, patients had daily electrocardiograms and troponin measurements until postoperative day 3 or discharge.

The primary outcome was the 30-day incidence of death or myocardial infarction (MI). Additional outcomes included the 30-day incidence of death or myocardial injury after noncardiac surgery (MINS), the 1-year mortality rate, and moderate to severe in-hospital perioperative complications.

Findings. Two percent of patients died or had an MI within 30 days of surgery.4

Subjective assessment had only a 19.2% sensitivity (95% confidence interval [CI] 14.2–25) but a 94.7% specificity (95% CI 93.2–95.9) for predicting inability to attain 4 metabolic equivalents during exercise.4

A lower Duke Activity Status Index predicted the primary outcome of death or MI within 30 days (adjusted odds ratio [OR] 0.96, 95% CI 0.83–0.99, P = .03), and it was the only measure that did so. Additionally, the Duke index and NT-proBNP level predicted the risk of death or MINS within 30 days.4

Only elevated NT-proBNP was associated with death at 1 year.4

On exercise testing, low peak oxygen consumption was significantly associated with perioperative complications.

Limitations. The number of primary outcome events (death and MI) was low, potentially affecting the statistical power of the study.

Conclusions. Subjective assessment of functional capacity misclassifies too many patients as being at low risk of perioperative complications and should not be used for preoperative risk stratification. Other tools, such as the Duke Activity Status Index and NT-proBNP levels, are better predictors of adverse perioperative cardiovascular outcomes and should be considered for use in preoperative cardiac risk assessment.

Although the Duke Activity Status Index is a better predictor of adverse outcomes than subjective functional capacity assessment, a specific perioperative threshold for risk classification has not been established. Its correlate for metabolic equivalents should be considered for use in clinical practice at this point.

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