# Stepwise Approach to Perioperative Cardiac Assessment — ACC/AHA 2014

## Overview

The 2014 ACC/AHA guideline provides a stepwise algorithmic approach to perioperative cardiovascular evaluation and management in patients with known or risk factors for coronary artery disease (CAD) who are undergoing noncardiac surgery. The algorithm integrates surgery urgency, active cardiac conditions, estimated perioperative risk of major adverse cardiac events (MACE), functional capacity, and the potential impact of further testing on patient management.

## The Stepwise Algorithm

### Step 1: Determine the Urgency of Surgery

- If the surgery is an **emergency** (i.e., life or limb is threatened if not in the operating room within a clinically appropriate timeframe), proceed directly to surgery.
- Clinical risk factors should be identified and documented, but emergency surgery should not be delayed for cardiac evaluation.
- Perioperative surveillance and management should be guided by the clinical assessment. (Class I, Level of Evidence: C)
- Risk factor modification and guideline-directed medical therapy (GDMT) should be pursued in the postoperative period.

### Step 2: Evaluate for Active Cardiac Conditions (Acute Coronary Syndrome)

- If the patient has an **acute coronary syndrome** (ACS), evaluate and treat the patient according to GDMT per the applicable UA/NSTEMI and STEMI clinical practice guidelines. (Class I, Level of Evidence: B)
- Active cardiac conditions that warrant evaluation and treatment before noncardiac surgery include:
  - **Unstable coronary syndromes** (unstable or severe angina, recent MI within 60 days)
  - **Decompensated heart failure** (NYHA functional class IV, worsening or new-onset HF)
  - **Significant arrhythmias** (high-grade AV block, Mobitz II AV block, third-degree AV block, symptomatic ventricular arrhythmias, supraventricular arrhythmias with uncontrolled ventricular rate > 100 bpm at rest, symptomatic bradycardia, newly recognized ventricular tachycardia)
  - **Severe valvular disease** (severe aortic stenosis with mean gradient >= 40 mmHg, aortic valve area < 1.0 cm2, or symptomatic; symptomatic mitral stenosis)
- If an active cardiac condition is present, the patient should be referred for cardiology evaluation and management prior to noncardiac surgery.
- If no active cardiac condition is present, proceed to Step 3.

### Step 3: Estimate the Perioperative Risk of MACE

- Estimate the risk of perioperative MACE based on the combined clinical and surgical risk using a validated risk-prediction tool. (Class IIa, Level of Evidence: B)
- The guideline endorses three acceptable tools:
  1. **Revised Cardiac Risk Index (RCRI)** (Lee Index)
  2. **ACS NSQIP MICA** (National Surgical Quality Improvement Program Myocardial Infarction and Cardiac Arrest calculator)
  3. **ACS NSQIP Surgical Risk Calculator**

> **OpenMedicine Calculator:** `calculate_rcri` -- available via MCP for automated RCRI scoring.

- Determine if the estimated risk is **low** (< 1% risk of MACE) or **elevated** (>= 1% risk of MACE).

### Step 4: Low Risk of MACE (< 1%)

- If the patient has a **low risk of MACE** (< 1%), no further testing is needed. Proceed to surgery. (Class IIa, Level of Evidence: B)
- For patients at low risk, further cardiac testing (e.g., stress testing) does not change management and is **not recommended**. (Class III: No Benefit, Level of Evidence: B)

### Step 5: Elevated Risk of MACE -- Assess Functional Capacity

- If the patient has an **elevated risk of MACE** (>= 1%), determine functional capacity using an objective measure or activity scale (e.g., the Duke Activity Status Index [DASI]).
- If the patient has **moderate, good, or excellent functional capacity** (>= 4 METs), proceed to surgery without further evaluation. (Class IIa, Level of Evidence: B)

#### Functional Capacity Estimation

| METs | Activity Examples |
|---|---|
| **1 MET** | Eating, dressing, walking around the house |
| **4 METs** | Climbing a flight of stairs, walking up a hill, walking on level ground at 4 mph, performing heavy work around the house (e.g., scrubbing floors, moving heavy furniture) |
| **> 10 METs** | Participation in strenuous sports (swimming, singles tennis, football, basketball, skiing) |

- Activities associated with **< 4 METs**: slow ballroom dancing, golfing with a cart, playing a musical instrument, walking at approximately 2 to 3 mph.
- The **4-MET threshold** is the critical cutoff: patients who can achieve >= 4 METs of work during daily activities without symptoms have a reassuring prognosis.

### Step 6: Elevated Risk and Poor or Unknown Functional Capacity

- If the patient has **poor functional capacity** (< 4 METs) or **unknown functional capacity**, the clinician should consult with the patient and the perioperative team to determine whether further testing will impact:
  - Patient decision making (e.g., whether to proceed with surgery)
  - Perioperative care (e.g., changes to anesthetic approach, monitoring, or medication management)
- If testing **will change management**, perform pharmacologic stress testing. (Class IIa, Level of Evidence: B)
  - If the stress test is normal, proceed to surgery according to GDMT.
  - If the stress test is abnormal, consider coronary angiography and revascularization depending on the extent of the abnormality, weighing cumulative risks.

### Step 7: Elevated Risk, Poor Functional Capacity, Testing Will Not Change Management

- If further testing **will not impact decision making or care**, proceed to surgery according to GDMT. (Class IIb, Level of Evidence: C)
- Alternative strategies should be considered, such as noninvasive treatment of the indication for surgery (e.g., radiation therapy for cancer) or palliation.

## Preoperative Noninvasive Stress Testing

- For patients with elevated risk and poor or unknown functional capacity, exercise stress testing is preferred if the patient can exercise. (Class IIa, Level of Evidence: B)
- Pharmacologic stress testing (dobutamine stress echocardiography or myocardial perfusion imaging) is appropriate for patients who cannot exercise. (Class IIa, Level of Evidence: B)
- **Routine screening** with noninvasive stress testing is **not useful** for patients undergoing low-risk surgery. (Class III: No Benefit, Level of Evidence: B)

## Preoperative Coronary Revascularization

- Coronary revascularization before noncardiac surgery is recommended in circumstances in which revascularization is indicated according to existing CPGs (e.g., ACS, significant left main disease). (Class I, Level of Evidence: C)
- **Routine** coronary revascularization is **not recommended** before noncardiac surgery exclusively to reduce perioperative cardiac events. (Class III: No Benefit, Level of Evidence: B)
- The CASS (Coronary Artery Surgery Study) registry demonstrated that patients who had undergone previous CABG had lower perioperative cardiac risk during subsequent noncardiac surgery compared with medically managed patients, but this does not justify prophylactic revascularization.

## Preoperative Resting 12-Lead ECG

- Preoperative resting 12-lead ECG is **reasonable** for patients with known coronary heart disease, significant arrhythmia, peripheral arterial disease, cerebrovascular disease, or other significant structural heart disease, except those undergoing low-risk surgery. (Class IIa, Level of Evidence: B)
- Preoperative resting 12-lead ECG **may be considered** for asymptomatic patients without known coronary heart disease, except those undergoing low-risk surgery. (Class IIb, Level of Evidence: B)
- Routine preoperative resting 12-lead ECG is **not useful** for asymptomatic patients undergoing low-risk surgical procedures. (Class III: No Benefit, Level of Evidence: B)

## Preoperative Assessment of LV Function

- Assessment of LV function is **reasonable** for patients with dyspnea of unknown origin. (Class IIa, Level of Evidence: C)
- Assessment of LV function is **reasonable** for patients with heart failure with worsening dyspnea or other change in clinical status. (Class IIa, Level of Evidence: C)
- Reassessment of LV function in clinically stable patients with previously documented LV dysfunction **may be considered** if there has been no assessment within 1 year. (Class IIb, Level of Evidence: C)
- Routine preoperative evaluation of LV function is **not recommended**. (Class III: No Benefit, Level of Evidence: B)

## Limitations

- The stepwise algorithm is based on a combination of available evidence and expert opinion. Several steps rely on Level of Evidence C (expert consensus).
- The algorithm applies specifically to patients with known or suspected CAD undergoing noncardiac surgery. It does not replace clinical judgment for unusual clinical scenarios.
- The term "elevated risk" was adopted instead of "intermediate" or "high" risk to simplify the previous 3-tier system into a 2-tier classification.
- Functional capacity assessment by clinical history has limited accuracy; the DASI questionnaire provides a more standardized assessment but is imperfect.
