A. Introduction. More than 200 million patients worldwide undergo noncardiac surgery each year. As the volume of procedures is increasing, so too is reliance on general internists and hospitalists to assist in the management of these patients. Perioperative cardiovascular complications are a major cause of morbidity and mortality.
B. The Preoperative Cardiovascular Risk Assessment: A Stepwise Approach
a. Determine the urgency of surgery
i. Emergency surgery (<6 hours). There is no role for formal risk assessment or risk reduction strategies because the patient needs to proceed to surgery immediately. Most surgeries related to trauma or acute abdominal catastrophes fall into this category.
ii. Urgent surgery (6–24 hours). A limited clinical evaluation is indicated in these patients because surgery must proceed in a timely manner. A classic example of urgent surgery is repair of a traumatic hip fracture.
iii. Time sensitive surgery (1–6 weeks). A thorough risk assessment is performed; however, some factors cannot be fully addressed because of time constraints (e.g., optimal blood sugar management in patients with diabetes). Most oncologic procedures are in this category.
iv. Elective surgery (could be delayed for up to 1 year). There is no time limitation for preoperative medical optimization for patients undergoing elective surgery. Examples include total hip or knee arthroplasty for patients with osteoarthritis.
b. Assess the patient for any active or unstable cardiovascular disease.
i. The perioperative period offers an opportunity to uncover undiagnosed cardiovascular conditions or detect worsening of preexisting diagnoses (e.g., ischemic heart disease or heart failure).
ii. If detected, active cardiovascular disease should be managed according to standard guidelines (see Chapters 10–12). Surgery should be postponed until the patient’s condition is fully assessed and optimized.
c. Estimate perioperative risk for major adverse cardiac events using a combined clinical/surgical risk tool.
i. The American College of Cardiology/American Heart Association (ACC/AHA) guidelines recommend using an objective risk tool to calculate perioperative cardiovascular risk. These tools include the Revised Cardiac Risk Index (RCRI) and the American College of Surgeons (ACS) NSQIP risk calculator (also known as the “Gupta risk index”).
1. RCRI. This includes six independent risk factors as follows:
a. Ischemic heart disease
c. Stroke or transient ischemic attack (TIA)
d. Diabetes mellitus on insulin therapy
e. Creatinine greater than 2 mg/dL
f. High-risk surgery (defined as intrathoracic, intraperitoneal, or major vascular surgery)
Having 0–1 risk factors indicates low risk for perioperative cardiovascular risk (~1%); 2 risk factors indicate intermediate risk (~5%); and 3 or more risk factors indicate high risk (~10%).
2. The ACS NSQIP calculator/Gupta risk index. This includes five elements to predict the risk for perioperative myocardial infarction and cardiac arrest. Calculating risk requires an online calculator or smartphone app to enter the following variables:
a. Type of surgery (20 options)
b. Dependent functional status (3 options)
c. Abnormal creatinine (i.e., ≥1.5 mg/dL)
d. ASA (American Society of Anesthesiology) class
ii. If the calculated perioperative risk is “low,” the patient may proceed to surgery with no further testing. If the estimated risk is “high,” the next step is to determine the patient’s functional capacity.
d. Determine the patient’s functional capacity.
i. Functional status is correlated with risk for perioperative events; high preoperative functional capacity is associated with fewer perioperative complications. Questionnaires such as the Duke Activity Status Index can be helpful to determine a patient’s functional capacity.
1. If a patient can achieve moderate/good functional capacity (4–10 METS) or excellent functional capacity (>10 METS), the patient may proceed to surgery without further testing (a rough rule of thumb is to estimate that 4 METS is climbing ≥1 flight of stairs without stopping or walking up hill for ≥1–2 blocks).
2. If a patient’s functional capacity is poor (<4 METS) or unknown, the next step is to determine whether further testing will affect decision-making or perioperative care.
e. Will further testing affect decision making or perioperative care?
i. If the answer is no, the patient may proceed to surgery with medical optimization. This, in fact, is the typical strategy for most patients. Alternatively, if it is determined the patient is at excessive perioperative risk, alternative strategies including noninvasive treatment or palliation can be considered.
ii. If the answer is yes, obtaining a pharmacologic stress test may be warranted. Consider the following regarding preoperative stress testing:
1. Although preoperative stress testing is known to have a high negative predictive value (i.e., a negative stress test is predictive of a low perioperative complication rate), stress testing has a very poor positive predictive value (i.e., a positive stress test is poorly predictive of perioperative complications).
2. Preoperative stress testing is recommended for patients with signs or symptoms of undiagnosed or unstable cardiac disease.
3. Stress testing can be considered for patients with a high or very high calculated perioperative risk using one of the recommended objective tools (see earlier), but only if it will change perioperative management.
4. If a stress test is performed and the results demonstrate significant myocardial ischemia, cardiology consultation is generally advised.
In most patients, preoperative stress testing is rarely indicated because it seldom changes perioperative management.
Suggested Further Readings
2014 ACC/AHA guideline on perioperative cardiovascular evaluation and management of patients undergoing noncardiac surgery: executive summary. J Nucl Cardiol 2015;22:162–215.Find this resource:
Devereaux PJ, Sessler DI. Cardiac complications in patients undergoing major noncardiac surgery. N Engl J Med 2015;373:2258–69.Find this resource:
Goldman L, Caldera DL, Nussbaum SR, et al. Multifactorial index of cardiac risk in noncardiac surgical procedures. N Engl J Med 1977;297:845–50. (Classic Article.)Find this resource:
Gupta PK, Gupta H, Sundaram A, et al. Development and validation of a risk calculator for prediction of cardiac risk after surgery. Circulation 2011;124:381.Find this resource:
Lee TH, Marcantonio ER, Mangione CM, et al. Derivation and prospective validation of a simple index for prediction of cardiac risk of major noncardiac surgery. Circulation 1999;100:1043. (Classic Article.)Find this resource: