Preoperative Cardiac Risk Assessment

Preoperative Cardiac Risk Assessment

Introduction

The aim of preoperative cardiac risk assessment is to identify patients at increased risk of perioperative cardiovascular complications.

• To detect any active or unstable cardiovascular disease requiring evaluation or treatment prior to surgery.
• Used to estimate the risk of major adverse cardiovascular events (MACE).
• Used to assess the functional capacity.
• It determines whether additional investigations will change the management plan.
• It will be used to optimize cardiovascular disease before surgery.
• Useful to decide whether surgery should proceed, or proceed with additional monitoring/optimization, or be temporarily deferred.

Stepwise Perioperative Approach (2024 AHA/ACC Guideline)

The 2024 AHA/ACC guideline recommends a stepwise approach to perioperative cardiovascular assessment. In this approach, the urgency of the surgery is first determined, followed by identification of active or unstable cardiovascular disease and estimation of the perioperative MACE risk.

Estimation of Perioperative MACE Risk

• Low risk (<1%) — usually proceed without routine cardiac stress testing.
• Elevated risk (≥1%) — assess functional capacity.
• Functional capacity ≥4 METs → usually proceed without routine stress testing.
• Functional capacity <4 METs → consider selective biomarkers and/or further testing if clinically indicated.

This raises the key question: Will the test result change management?

Surgical Risk Classification

Procedure-Specific Cardiac Risk (2022 ESC Guidelines)

Classification scheme for procedure-specific cardiac risk in the 2022 European Society of Cardiology guidelines:

Low Cardiac Risk

Breast surgery, dental surgery, thyroid surgery, eye surgery, minor gynecologic surgery, minor orthopedic surgery, urologic surgery, minimally invasive minor lung resection.

Intermediate Cardiac Risk

Carotid surgery (asymptomatic), endovascular aortic aneurysm repair, head or neck surgery, intermediate-risk intraperitoneal surgery (splenectomy, hiatal hernia repair, cholecystectomy), major neurologic or orthopedic surgery (joint replacement, spine surgery), peripheral arterial angioplasty, kidney transplant, major urologic or gynecologic surgery.

High Cardiac Risk

Adrenal resection, aortic and major vascular surgery, carotid surgery (symptomatic), high-risk intraperitoneal surgery (bile duct surgery, esophagectomy, perforated bowel repair), amputation, pneumonectomy, liver transplant, lung transplant, limb revascularization surgery.

Cardiovascular Risk-Prediction Tools

According to the 2024 guideline, several validated perioperative risk prediction approaches exist. No single calculator is established as universally superior.

• Revised Cardiac Risk Index (RCRI)
• NSQIP Risk Calculator
• NSQIP: MICA
• Surgical Outcome Risk Tool

Revised Cardiac Risk Index (RCRI), 1999 (also called the Lee Index)

A simple, validated and widely used bedside tool. It uses six predictors, with 1 point assigned for each:

• Ischemic heart disease
• Cerebrovascular disease
• History of heart failure
• Diabetes mellitus requiring insulin therapy
• Serum creatinine ≥ 2 mg/dL
• High-risk surgery

Evolution of Risk Prediction Models

Risk prediction has evolved from early multifactorial clinical scores to procedure-specific and large database prediction models. The modern approach uses a validated risk calculator together with surgical risk, functional capacity, frailty, symptoms, and selected biomarkers, rather than relying on a single score.

(1) Goldman Cardiac Risk Index (1977)

• It is the first major multifactorial cardiac risk index.
• The original model used clinical findings, ECG, age, cardiac disease, and the type/urgency of surgery.

(2) Detsky Modified Cardiac Risk Index (1986)

• A modification of the Goldman Index.
• Added clinical variables such as angina and previous myocardial infarction.
• Represents an intermediate step in the evolution toward more clinically detailed risk prediction.

(3) NSQIP-Derived Models

• Large surgical databases allow risk models to incorporate both patient and procedure characteristics.
• They can predict multiple postoperative outcomes, including myocardial infarction, cardiac arrest, pneumonia, and acute kidney injury.

(4) Gupta NSQIP Risk Calculator (2011)

This model is specifically focused on perioperative myocardial infarction and cardiac arrest. Five major predictors:

• Type of surgery/procedure
• Functional status
• Serum creatinine
• ASA physical status
• Age

(5) Duke Activity Status Index (DASI)

• A structured tool for assessing functional capacity.
• Contains 12 daily activities.
• Score range: 0–58.2.
• Higher score indicates better functional status.

Functional Capacity

Functional capacity is an important predictor of perioperative cardiovascular events and is usually expressed in Metabolic Equivalents (METs). One MET represents an oxygen consumption of 3.5 mL/kg/min.

• The 2024 ACC/AHA guideline uses 4 METs as the threshold for poor functional capacity.
• Ability to climb 2 flights of stairs corresponds approximately to > 4 METs.
• Poor functional capacity is associated with increased perioperative cardiovascular risk.

Identifying Active or Unstable Cardiovascular Disease

• Presence of acute coronary syndrome
• Unstable or accelerating angina
• Decompensated heart failure
• Significant uncontrolled arrhythmia
• Severe symptomatic valvular disease
• Other clinically unstable cardiovascular conditions

If an unstable cardiovascular condition is present, elective surgery should generally be deferred while the condition is evaluated and treated.

Preoperative Biomarkers

For patients undergoing elevated-risk non-cardiac surgery who have known cardiovascular disease, age ≥ 65 years, or age ≥ 45 years with symptoms suggestive of cardiovascular disease:

Electrocardiography (ECG)

• Useful when there is known cardiovascular disease, cardiovascular symptoms, or elevated-risk surgery.
• Routine ECG is NOT required for every low-risk patient.
• It may identify prior MI, ischemic changes, conduction abnormalities, ventricular hypertrophy, or significant arrhythmias.

Echocardiography

Performed when clinically indicated, particularly with new or worsening heart failure symptoms, unexplained dyspnea, known significant ventricular dysfunction, or suspected valvular disease.

Stress Testing

The 2024 ACC/AHA guideline emphasizes avoiding routine stress testing when it is unlikely to change management. Stress testing should be selective.

Coronary CT Angiography (CCTA)

• May be considered selectively in appropriate patients as part of perioperative coronary assessment.
• Particular concern is identification of significant coronary disease, including possible left main or multivessel disease.

Invasive Coronary Angiography

• Routine invasive coronary angiography with intent to revascularize before elective non-cardiac surgery is NOT recommended in patients with stable CAD.
• Indications include acute coronary syndrome, accelerating angina despite maximal therapy, newly diagnosed moderate-to-severe ischemia, or evidence of obstructive left main disease.

Frailty

• An important risk marker, particularly in older adults.
• It is associated with increased postoperative mortality and complications.
• Prehabilitation can be beneficial in selected patients.

Major Cardiac Conditions and Perioperative Concerns

When to Proceed vs. When to Pause

Perioperative Optimization

• Optimize hypertension when clinically appropriate.
• Optimize heart failure and volume status.
• Manage clinically significant arrhythmias.
• Review antiplatelet and anticoagulant therapy.
• Assess recent coronary intervention and stent-related considerations.
• Consider frailty and functional status.
• Plan appropriate postoperative cardiovascular surveillance in high-risk patients.
• SGLT2 inhibitors should be discontinued 3–4 days before surgery to reduce the risk of perioperative ketoacidosis.

‘Do Not Overtest’ Rule

• Avoid routine stress testing in low-risk patients.
• Avoid routine stress testing in patients with adequate functional capacity and stable symptoms.
• Avoid routine invasive coronary angiography in stable CAD.
• Avoid cardiac imaging when there is no clinical indication.
• A test should be performed when its result is likely to change management.

Summary

• MACE risk ≥ 1% → Elevated perioperative risk.
• RCRI > 1 is traditionally used as a threshold for elevated risk.
• 4 METs is the important threshold for poor functional capacity.
• Good functional capacity generally argues against routine stress testing.
• BNP > 92 ng/L or NT-proBNP ≥ 300 ng/L is abnormal, while Troponin > 99th percentile upper reference limit is abnormal.
• Routine invasive coronary angiography is NOT recommended for stable CAD.
• Cardiovascular disease should be evaluated and treated according to usual clinical indications, NOT simply because surgery is planned.
• Frailty should be considered, particularly in older adults.
• Complex or unstable cardiovascular disease may require team-based management.
• Risk assessment is no longer based on a single score — use a validated risk calculator (RCRI / NSQIP-based tool) when appropriate.

References

1. Thompson A, Fleischmann KE, Smilowitz NR, et al. 2024 AHA/ACC/ACS/ASNC/HRS/SCA/SCCT/SCMR/SVM guideline for perioperative cardiovascular management for noncardiac surgery. Circulation. 2024;150:e351-e442. doi:10.1161/CIR.0000000000001285.

2.Miller RD, et al. Miller’s Anesthesia. 10th edition.