Old MI: Preoperative risk assessment
Clinical - Cardiovascular
For preoperative risk assessment, the age of a myocardial infarction (MI) is important. Acute MI is defined as occurring within the past 7 days. Recent MI is defined as happening between 7 and 30 days ago. Both acute and recent MIs, along with unstable angina, are considered unstable coronary syndromes and place the patient at considerably higher risk for a perioperative cardiac event. According to the 2014 ACC/AHA Guidelines for Perioperative Cardiovascular Evaluation and Care for Non-Cardiac Surgery, the following conditions should prompt delay of elective non-cardiac surgery for further assessment and treatment:
- Unstable coronary syndromes
- Decompensated heart failure
- Significant arrythmias
- Severe valvular disease
Having an older MI (i.e. > 30 days ago) is a clinical risk factor for perioperative cardiac morbidity, falling under one of the variables of the (Lee) Revised Cardiac Risk Index.
Revised Cardiac Risk Index Variables:
- History of ischemic heart disease
- History of congestive heart failure
- History of cerebrovascular disease
- Insulin therapy for diabetes
- Preoperative serum creatinine > 2.0 mg/dL
- High-risk type of surgery
Unless the patient with an old MI has at least 2 more of the above risk factors, and either poor (<4 METs) or unknown functional capacity, surgery should proceed without further workup.