There are guidelines to help the clinician and patient better define the risk of both cardiac and noncardiac surgery in heart patients. The easiest to use algorithms for cardiac surgery can be found on either of two websites: one includes the euroSCORE (www.euroSCORE.org/calc.html) and the other the STS (Society of Thoracic Surgeons) database that provides a longitudinal look at the risk of cardiac surgery (http://www.sts.org/national-database). The EuroScore method invariably results in a greater risk score than the STS. These preoperative guidelines and algorithms are also available as smartphone applications (preop cardiac evaluation, STS scoring system, ACC/AHA risk of noncardiac surgery algorithm).
The assessment of the risk of noncardiac surgery in cardiac patients is addressed by the 2014 ACC/AHA Task Force which provides clinically useful algorithms to help determine risk including the controversy surrounding beta-blocker prophylaxis. The major cardiovascular societies have also outlined an approach to assessing risk for cardiac patients that need noncardiac surgery. It basically follows a stepwise approach that assesses the clinical status of the patient and combines that with the inherent risk of the surgical procedure (eFigure 10–83). There are societies that have provided multivariate risk models. The Revised Cardiac Risk Index (RCRI) is most commonly used and is available as a smartphone or computer application. Others include the American College of Surgeons National Quality Improvement Program (NSQIP), Myocardial Infarction and Cardiac Arrest calculator, and the American College of Surgeons NSQIP Surgical Risk Calculator. Each of these can be found on-line to address an individual patient risk. The RCRI takes into account the risk of the noncardiac surgery, the status or presence of ischemic heart disease, the history of heart failure, the history of cerebrovascular disease, the preoperative need for insulin, and renal function. In 2017, the Canadian Cardiovascular Society published their own interpretation of prior guidelines and made a variety of new suggestions regarding the assessment of cardiovascular patients prior to noncardiac surgery. Some of the suggestions from the Canadian Cardiovascular Society included measuring the NT-proBNP or BNP prior to surgery and troponin levels after, avoiding most cardiovascular testing prior to noncardiac surgery, against perioperative use of aspirin or beta-blockers and in favor of withholding ARBs or ACE inhibitors prior to the surgery. Details can be found online. In 2019, the American College of Surgeons published the risk of noncardiac surgery in heart patients based on their National Surgical Quality Improvement Program database. After analysis of almost 1.2 million patients, their multivariate risk features included age older than 75, history of heart disease, hemoglobin less than 12 mg/dL, vascular surgery, and emergency surgery. Each factor was assigned a point (total then 0, 1, 2, 3, greater than 3). An adverse outcome was noted in 0%, 0.5%, 2.0%, 5.6%, and 15.7% respectively.
American College of Cardiology/American Heart Association (ACC/AHA) stepwise approach to perioperative cardiac assessment for coronary artery disease (CAD). (Reproduced, with permission, from McKean SC, Ross JJ, Dressler DD, et al. Principles and Practice of Hospital Medicine, 2nd ed. McGraw-Hill, 2017.)
Patients with known or suspected cardiac disease undergoing general surgery present a common management problem. Anesthesia and surgery are often associated with marked fluctuations of heart rate and BP, changes in intravascular volume (often patients leave surgery markedly volume overloaded), myocardial ischemia or depression, arrhythmias, decreased oxygenation, increased sympathetic nervous system activity, and alterations in medical regimens and pharmacokinetics. Even with careful monitoring and management, the perioperative period can be very stressful to cardiac patients.
The risk of surgery in patients with heart disease depends primarily on three factors: the type of operation, the nature of the heart disease, and the degree of preoperative stability. The type of anesthesia is less important, though halothane, enflurane, and barbiturates are more severe myocardial depressants, whereas opioids have little depressive effect. Spinal and epidural anesthesia were previously thought to be preferable in patients with heart disease, but this has not proved to be the case.
Numerous studies have evaluated the excess risk of surgery in patients with various cardiac diseases. Recent (within 3 months) MI, unstable angina, heart failure, and significant aortic stenosis are associated with substantial increases in operative morbidity and mortality rates. Any degree of instability in these conditions magnifies the potential risk. Stable angina, particularly in an inactive individual, is also associated with a higher operative risk. Although less common, cyanotic congenital heart disease and severe primary or secondary pulmonary hypertension pose great risks during major surgery. In patients with any of these problems, the risk-to-benefit ratio of the planned surgery should be carefully examined. If the procedure is necessary but elective, consideration should be given to delaying it until full recovery postinfarction and correction or optimal stabilization of the other conditions are achieved. Hypertension should be at least moderately controlled. Patients with severe angina should have increased medical therapy initiated or be considered for revascularization before noncardiac surgery. Symptomatic arrhythmias, nonsustained ventricular tachycardia, or high-grade AV block and cardiac failure should be treated optimally.
Clinical assessment provides the most useful guidance in determining the risk of noncardiac surgery. Important indicators of high risk have been discussed above. Patients with known but clinically stable heart disease, such as angina pectoris or prior MI, are at intermediate risk, particularly for major operations such as vascular surgery. If a history or symptoms of heart failure are present, assessment of LV function can be very helpful in perioperative management. Although frequently advocated, further noninvasive testing for myocardial ischemia for the purpose of risk stratification is probably overutilized. Tests such as stress myocardial perfusion scintigraphy or dobutamine echocardiography should be reserved for situations in which the results may alter patient management. There is no evidence that prophylactic revascularization by either PCI or coronary artery bypass surgery alters long-term outcome in patients undergoing noncardiac surgical procedures without the usual indications for PCI or CABG. Only in the case of major vascular operations is perioperative mortality and morbidity high enough that prophylactic PCI or CABG should be considered.
However, it should be noted that many patients undergoing surgery have not had recent medical follow-up, and this may be an appropriate opportunity to perform a more complete evaluation. Thus, stress testing may be indicated for selected patients with symptomatic angina or prior MI with a view to instituting more comprehensive medical management or performing coronary revascularization to reduce long-term (rather than perioperative) mortality and morbidity. At the least, such patients should not be discharged without a plan for an appropriate follow-up and institution of antihyperlipidemic, aspirin, and beta-blocker therapy as indicated.
Once the decision to operate is made, careful management is essential. Most cardiac medications should be continued preoperatively and postoperatively. In patients judged to be at medium or high risk, there has been controversy regarding the use of beta-blockers. Data do not support their value in most situations preoperatively. Monitoring is an important prophylactic measure in high-risk individuals; hemodynamic monitoring can facilitate early intervention in patients with heart failure, severe valve disease, or easily induced myocardial ischemia. Excessive hypertension, hypotension, and myocardial ischemia should be identified and appropriately treated using rapidly acting agents. TEE can also be used for intraoperative monitoring of ischemia, but its value has never been established in well-designed studies. Ischemic events, whether symptomatic or silent, should be vigorously treated.
et al. A new index for pre-operative cardiovascular evaluation. J Am Coll Cardiol. 2019 Jun 25;73(24):3067–78.
et al. Canadian Cardiovascular Society Guidelines on perioperative cardiac risk assessment and management for patients who undergo noncardiac surgery. Can J Cardiol. 2017 Jan;33(1):17–32.
et al. 2014 ACC/AHA guideline on perioperative cardiovascular evaluation and management of patients undergoing noncardiac surgery: a report of the American College of Cardiology/American Heart Association Task Force on practice guidelines. J Am Coll Cardiol. 2014 Dec 9;64(22):e77–137.