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

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ABSTRACTIn August 2014, the American College of Cardiology and American Heart Association updated their guidelines on cardiovascular evaluation and care before noncardiac surgery and simultaneously published a systematic review of perioperative use of beta-blockers. The update reinforces many previous recommendations and provides new evidence and expert opinion that is useful to the perioperative team.

KEY POINTS

  • Like earlier guidelines, the update recommends preoperative cardiac testing only when the results may influence the patient’s management.
  • Preoperative intervention is rarely necessary just to get the patient through surgery, unless it is otherwise indicated independent of the need for surgery.
  • The update proposes a modified algorithm for preoperative risk assessment and management and suggests using a new calculator of surgical risk.
  • The report also updates information on the timing of surgery after percutaneous coronary intervention, as well as on antiplatelet therapy, other medical therapy, and biomarkers.


 

References

Guidelines jointly issued by the American College of Cardiology and American Heart Association (ACC/AHA)1 provide a framework for evaluating and managing perioperative cardiac risk in noncardiac surgery. An overriding theme in successive documents from these organizations through the years has been that preoperative intervention, coronary artery bypass grafting, or percutaneous coronary intervention is rarely necessary just to get the patient through surgery, unless it is otherwise indicated independent of the need for surgery.

See related commentary

This article highlights some of the key recommendations in the 2014 updates to these guidelines,1–3 how they differ from previous guidelines,4 and the ongoing challenges and unresolved issues facing physicians involved in perioperative care.

Of note, while these guidelines were being updated, Erasmus University5 expressed concern about the scientific integrity of some of the Dutch Echocardiographic Cardiac Risk Evaluation Applying Stress Echocardiography (DECREASE) trials. As a result, the evidence review committee included these trials in its analysis but not in a systematic review of beta-blockers.2 These trials were not included in the clinical practice guideline supplements and tables but were cited in the text if relevant.

The European Society of Cardiology and European Society of Anesthesiology6 revised their guidelines concurrently with but independently of the ACC/AHA, and although they discussed and aligned some recommendations, many differences remain between the two sets of guidelines. Readers should consult the full guidelines for more detailed information.1

THE ROLE OF THE PREOPERATIVE CARDIAC EVALUATION

The purpose of preoperative medical evaluation is not to "get medical clearance" but rather to evaluate the patient’s medical status and risk of complications. The process includes:

  • Identifying risk factors and assessing their severity and stability
  • Establishing a clinical risk profile for informed and shared decision-making
  • Recommending needed changes in management, further testing, or specialty consultation.

The updated guidelines emphasize the importance of communication among the perioperative team and with the patient. They reiterate the focus on appropriateness of care and cost containment—one should order a test only if the result may change the patient’s management.

HOW URGENT IS SURGERY? HOW RISKY?

The new guidelines classify the urgency of surgery as follows:

  • Emergency (necessary within 6 hours)
  • Urgent (necessary within 6–24 hours)
  • Time-sensitive (can delay 1–6 weeks)
  • Elective (can delay up to 1 year).

One should order a test only if the result may change the patient's management

Surgical risk is now classified as either low (< 1% risk of major adverse cardiac events) or elevated (≥ 1%) on the basis of surgical and patient characteristics. Previous schemas included an intermediate-risk category. Low-risk procedures include endoscopic procedures, superficial procedures, cataract surgery, breast surgery, and ambulatory surgery. Elevated-risk procedures include vascular surgery, intraperitoneal and intrathoracic surgery, head and neck surgery, orthopedic surgery, and prostate surgery.

Risk calculators and biomarkers

To estimate the perioperative risk of major adverse cardiac events, the guidelines suggest incorporating the Revised Cardiac Risk Index (RCRI)7 with an estimation of surgical risk or using a newer surgical risk calculator derived from a database of the American College of Surgeons’ National Surgical Quality Improvement Project (ACS NSQIP).

The RCRI is based on six risk factors, each worth 1 point:

  • High-risk surgery
  • Ischemic heart disease
  • Heart failure
  • Stroke or transient ischemic attack
  • Diabetes requiring insulin
  • Renal insufficiency (serum creatinine > 2.0 mg/dL).7

MICA. The Myocardial Infarction or Cardiac Arrest (MICA) calculator8 has a narrower focus and was validated in only one center.

ACS NSQIP. The recommended newer ACS NSQIP surgical risk calculator9 provides an estimate of procedure-specific risk based on Current Procedural Terminology code and includes 21 patient-specific variables to predict death, major adverse cardiac events, and eight other outcomes. While more comprehensive, this risk calculator has yet to be validated outside of the ACS NSQIP database.

Reconstructed RCRI. The RCRI has been externally validated, but it underestimates risk in major vascular surgery and was outperformed by the MICA calculator. Although not discussed in the new guidelines, a recently published "reconstructed RCRI,"10 in which a serum creatinine level greater than 2 mg/dL in the original RCRI is replaced by a glomerular filtration rate less than 30 mL/min and diabetes is eliminated, may outperform the standard RCRI. A patient with either an RCRI score or a reconstructed RCRI score of 0 or 1 would be considered to be at low risk, whereas patients with two or more risk factors would have an elevated risk.

Cardiac biomarkers, primarily B-type natriuretic peptide (BNP) and N-terminal (NT) proBNP, are independent predictors of cardiac risk, and their addition to preoperative risk indices may provide incremental predictive value. However, how to use these biomarkers and whether any treatment aimed at them will reduce risk is unclear, and the new guidelines did not recommend their routine use.

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