Risk of Major Adverse Cardiac Events (MACE) in ASA 4 Patients

Understanding ASA 4 Classification

The American Society of Anesthesiologists (ASA) defines ASA IV as a patient with severe systemic disease that is a constant threat to life 1
ASA 4 patients have severe systemic diseases with substantive functional limitations that pose a constant threat to life, representing the highest-risk category of patients who can still undergo elective procedures 1
Examples of ASA 4 conditions include recent myocardial infarction, stroke, or transient ischemic attack, ongoing cardiac ischemia, severe valve dysfunction, and decompensated heart failure 1

ASA 4 classification is independently associated with increased perioperative mortality and morbidity, with cardiac complications being among the most common adverse outcomes 2, 3
In patients with ASA 4 classification, the risk of MACE is substantially higher than in patients with lower ASA classifications, with rates exceeding 5% for major cardiac complications 4, 5
The 2024 American Heart Association/American College of Cardiology guidelines identify ASA classification as a key component in perioperative risk assessment, with ASA 4 patients falling into the "elevated risk" category (≥1% risk of MACE) 4, 5

Coronary artery disease is prevalent in approximately 18% of patients undergoing major noncardiac surgery and is associated with increased risk of perioperative MACE 4
History of acute coronary syndrome confers greater perioperative risks than chronic coronary disease, with a 3.5-fold increased risk of perioperative MACE 4
Heart failure is an established risk factor for poor outcomes after noncardiac surgery, with 90-day mortality rates of 5.49% for symptomatic heart failure patients 6
Severely reduced left ventricular ejection fraction is an independent predictor of 30-day mortality in patients undergoing intermediate and high-risk procedures 6

The Revised Cardiac Risk Index (RCRI) is commonly used to assess perioperative risk of major cardiac complications, though it may have poorer discrimination in patients undergoing vascular surgery 3
Functional capacity assessment using tools like the Duke Activity Status Index (DASI) is reasonable to further stratify risk in ASA 4 patients undergoing elevated-risk noncardiac surgery 3

ASA 4 patients require careful preoperative optimization and may benefit from more intensive perioperative monitoring 2
Preoperative assessment of left ventricular function is indicated in ASA 4 patients with unexplained cardiac symptoms and may be reasonable with elevated preoperative B-type natriuretic peptide or NT-proBNP concentrations 6
For ASA 4 patients with aortic stenosis, elevated-risk elective noncardiac surgery with appropriate intraoperative and postoperative hemodynamic monitoring is reasonable 2

Underestimation of MACE risk in ASA 4 patients can lead to inadequate perioperative monitoring and management 4, 2