The most important perioperative cardiac complications are myocardial infarction (MI) and cardiac death. Other complications include heart failure (HF), arrhythmias, and unstable angina. The principal patient-specific risk factor is the presence of end-organ cardiovascular disease. This includes not only coronary artery disease and HF but also cerebrovascular disease and chronic kidney disease. Diabetes mellitus, especially if treated with insulin, is considered a cardiovascular disease equivalent that increases the risk of cardiac complications. Major abdominal, thoracic, and vascular surgical procedures (especially abdominal aortic aneurysm repair) carry a higher risk of postoperative cardiac complications, likely due to their associated major fluid shifts, hemorrhage, and hypoxemia. These risk factors were identified in a validated, multifactorial risk prediction tool: the Revised Cardiac Risk Index (RCRI) (Table 3–2). Another risk prediction tool, derived from the American College of Surgeons’ National Surgical Quality Improvement Program (NSQIP) patient database, identified patient age, the location or type of operation, serum creatinine greater than 1.5 mg/dL (132.6 mcmol/L), dependency in activities of daily living, and the patient’s American Society of Anesthesiologists physical status classification as predictors for postoperative MI or cardiac arrest. An online risk calculator using the NSQIP tool can be found at http://www.qxmd.com/calculate-online/cardiology/gupta-perioperative-cardiac-risk. The American College of Cardiology and American Heart Association endorse both prediction tools. Patients with two or more RCRI predictors or a risk of perioperative MI or cardiac arrest in excess of 1% as calculated by the NSQIP prediction tool are deemed to be at elevated risk for cardiac complications.
Table 3–2.Revised Cardiac Risk Index. |Favorite Table|Download (.pdf) Table 3–2. Revised Cardiac Risk Index.
|Independent Predictors of Postoperative Cardiac Complications |
|1. Intrathoracic, intraperitoneal, or suprainguinal vascular surgery |
|2. History of ischemic heart disease |
|3. History of heart failure |
|4. Insulin treatment for diabetes mellitus |
|5. Serum creatinine level > 2 mg/dL [> 176.8 mcmol/L] |
|6. History of cerebrovascular disease |
|Scoring (Number of Predictors Present) ||Risk of Major Cardiac Complications1 |
|None ||0.4% |
|One ||1% |
|Two ||2.4% |
|More than two ||5.4% |
Limited exercise capacity (eg, the inability to walk for two blocks at a normal pace or climb a flight of stairs without resting) also predicts higher cardiac risk. Emergency operations are also associated with greater cardiac risk, but should not be delayed for extensive cardiac evaluation. Instead, patients facing emergency surgery should be medically optimized for surgery as quickly as possible and closely monitored for cardiac complications during the perioperative period.
ROLE OF PREOPERATIVE NONINVASIVE ISCHEMIA TESTING
Most patients can be accurately risk-stratified by history and physical examination. A resting electrocardiogram (ECG) should also be obtained in patients with at least one RCRI predictor prior to major ...