Preoperative Cardiac Evaluations
Every year, more than 26.8 million surgical procedures occur in the United States [1]. Among the 1.5% of deaths occurring in the 30 days following surgery, the most common fatal complications are cardiac [1]. These complications include heart rhythm disorders, myocardial infarction, and heart failure [2]. To prevent perioperative cardiac complications and reduce patient mortality, thorough preoperative cardiac evaluations are crucial.
The major preoperative cardiac guidelines emphasize the same basic elements: a cardiac risk assessment, which incorporates a physical examination, patient history, and the intrinsic risk level of the particular procedure [3]. With this information, physicians will be able to determine whether the patient has undiagnosed cardiac conditions, requires further testing, and/or faces a high risk of a major adverse cardiac event (MACE) that necessitates an altered course of action [3].
In the US, preoperative cardiac evaluations tend to follow the clinical practice guidelines established by the American College of Cardiology (ACC) and the American Heart Association (AHA) [2]. These guidelines outline an algorithm that allows physicians to adequately account for cardiac risk when preparing for surgery [3]. The steps consist of five basic questions:
- Does the patient require emergency noncardiac surgery?
- Does the patient have active cardiac conditions that require treatment before surgery?
- What is the cardiac risk of the planned surgery?
- What is the patient’s functional capacity without symptoms?
- Does the patient exhibit any clinical risk factors? [4]
Unfortunately, some patients with cardiac difficulties may require emergency surgery, despite the suboptimal nature of their cardiac health. However, when treating patients for whom surgery can be delayed, physicians have a greater chance of achieving cardiac stability before the operation. As such, when conducting the physical examination and gathering the patient’s history, medical teams should pay close attention to the following: decompensated heart failure, unstable angina, arrhythmia, value disease, ST-elevated myocardial infarction (STEMI), and non-STEMI [5].
As for the risk levels of particular surgeries, most ophthalmologic, endoscopic, dermatologic, and breast-related operations are largely considered safe [4]. However, after analyzing data from more than 3.2 million surgical patients, Liu et al. found that the traditional approach of estimating surgical risk levels according to physiology, anatomy, or surgical specialty is not entirely accurate [1]. As a result, providers should look past basic categories and strive to analyze procedure-specific data concerning cardiac risk when gauging the complication probability of a particular type of operation.
To measure functional capacity, medical teams frequently rely on qualitative measures of patients’ metabolic equivalents (METs) [2]. For reference, activities associated with daily living require a capacity of 1 to 2 METs, while demanding physical activity requires more than 10 METs [4]. Patients whose functional capacity measures at fewer than 4 METs, or is unknown, are generally at higher cardiac risk during surgery [3].
Lastly, clinical risk factors are conditions that, according to many studies, are associated with a heightened risk of cardiac events during surgery [4]. They include: diabetes mellitus, history of compensated previous congestive heart failure, history of ischemic heart disease, history of cerebrovascular disease, and renal insufficiency [4].
Patients with these risk factors may require accommodations during surgery or prompt the adoption of a new surgical procedure altogether.
Ultimately, conducting preoperative cardiac evaluations that effectively gauge patient risk before surgery is important. Not only does meaningful risk assessment allow patients to make informed decisions about their healthcare, but it also facilitates preoperative medical optimization, essential cardiac interventions, and safe operations overall [1].
References
[1] J. B. Liu et al., “Defining the Intrinsic Cardiac Risks of Operations to Improve Preoperative Cardiac Risk Assessments,” Anesthesiology, vol. 128, pp. 283-292, February 2018. [Online]. Available: DOI: 10.1097/ALN.0000000000002024.
[2] G. Santangelo et al., “Risk of cardiovascular complications during non-cardiac surgery and preoperative cardiac evaluation,” Trends in Cardiovascular Medicine, vol. 16, no. 12, pp. 1-14, July 2021. [Online]. Available: DOI: 10.1016/j.tcm.2021.06.003.
[3] D. Raslau et al., “Preoperative Cardiac Risk Assessment,” Thematic Review on Perioperative Medicine, vol. 95, no. 5, pp. 1064-1079, May 2020. [Online]. Available: DOI: 10.1016/j.mayocp.2019.08.013.
[4] W. K. Freeman and R. J. Gibbons, “Perioperative Cardiovascular Assessment of Patients Undergoing Noncardiac Surgery,” Mayo Clinic Proceedings, vol. 84, no. 1, pp. 79-90, January 2009. [Online]. Available: DOI: 10.1016/S0025-6196(11)60812-4.
[5] C. P. Spanos, “Preoperative Cardiac Evaluation,” in Acute Surgical Topics: An Infographic Guide, vol. 128, New York: Springer, 2021, pp. 5-7.