Residency · Residency · Internal Medicine

Perioperative Cardiovascular Risk Assessment

Overview and Scope

Perioperative cardiovascular complications are a leading cause of morbidity and mortality in non-cardiac surgery. With more than 200 million non-cardiac surgeries performed annually worldwide, major adverse cardiac events occur in 1 to 5 percent of cases. The internist's role encompasses risk stratification, optimization of modifiable risk factors, perioperative medication management, and postoperative surveillance.

Stepwise Approach to Perioperative Cardiac Evaluation (ACC/AHA 2014 Guidelines)

Step 1: Is the Surgery an Emergency?

If the surgery is emergent, the patient should proceed directly to the operating room with perioperative risk management and surveillance in place. There is no time for extensive preoperative cardiac testing in this scenario.

Step 2: Does the Patient Have an Acute Coronary Syndrome?

Certain active cardiac conditions require evaluation and management before any elective surgery can proceed. These include unstable angina or recent MI (within 60 days), decompensated heart failure, significant arrhythmias (high-grade AV block, symptomatic ventricular arrhythmias, supraventricular tachycardia with uncontrolled rate), and severe valvular disease (symptomatic aortic stenosis, symptomatic mitral stenosis).

Step 3: Estimate Surgical Risk

Procedures are categorized as low-risk (less than 1 percent cardiac risk), which includes endoscopy, superficial procedures, cataract surgery, breast surgery, and ambulatory surgery, or elevated-risk (1 percent or greater cardiac risk), which includes intraperitoneal, intrathoracic, vascular, orthopedic (hip and knee), head and neck, and prostate surgery.

Step 4: Assess Functional Capacity

Functional capacity is measured in metabolic equivalents (METs). A patient who can achieve 4 or more METs without symptoms -- equivalent to climbing one flight of stairs, walking two blocks at normal pace, or doing heavy housework -- can generally proceed to surgery without further cardiac testing. When functional capacity is less than 4 METs or unknown, additional risk assessment is warranted. The DASI questionnaire is a validated tool for estimating functional capacity and is more objective than clinical estimation alone.

Step 5: Use the Revised Cardiac Risk Index (RCRI/Lee Index)

The RCRI comprises six independent predictors of perioperative cardiac complications:

The risk of major adverse cardiac events increases with the number of predictors present: 3.9 percent with 0 points, 6.0 percent with 1 point, 10.1 percent with 2 points, and 15 percent or more with 3 or more points.

ACS NSQIP Surgical Risk Calculator

The ACS NSQIP calculator provides more granular risk prediction by incorporating procedure-specific data and 21 patient variables. Available online, it estimates risk for multiple outcomes including cardiac complications, mortality, and surgical site infection. It is increasingly favored over RCRI alone for individualized risk assessment.

Preoperative Cardiac Testing

When to Order (and When NOT to Order)

Preoperative stress testing is not indicated for low-risk surgery, for patients with functional capacity of 4 or more METs without symptoms, or as routine screening before any surgery. Stress testing should be considered only when the patient is undergoing elevated-risk surgery with poor or unknown functional capacity and an RCRI of 1 to 2 or greater, and only when the results would actually change management.

Types of Stress Testing

An exercise stress test is preferred when the patient can exercise, as it also provides functional capacity data. Pharmacologic stress testing with dobutamine echocardiography or regadenoson/dipyridamole nuclear imaging is used for patients who cannot exercise. Coronary CT angiography is not established for routine preoperative assessment.

Preoperative Echocardiography

Echocardiography is not indicated routinely before surgery. It is reasonable when there is suspected new or worsening heart failure, a new murmur concerning for significant valvular disease, or dyspnea of unknown etiology. Patients with known severe aortic stenosis should have reassessment if no echocardiogram has been performed within the past year.

Preoperative Coronary Revascularization

The CARP trial demonstrated that prophylactic preoperative coronary revascularization does not reduce perioperative MI or mortality in patients with stable coronary artery disease undergoing vascular surgery. The indications for revascularization remain the same as in non-surgical patients (acute coronary syndromes, left main disease). Coronary stents create timing dilemmas because elective surgery must be delayed to allow completion of dual antiplatelet therapy: at least 30 days after a bare-metal stent, and at least 6 months (ideally 12 months) after a drug-eluting stent, with a minimum of 3 months in urgent situations.

Preoperative Laboratory and ECG

A 12-lead ECG is reasonable for patients with known cardiovascular disease, significant arrhythmia, structural heart disease, or those undergoing elevated-risk surgery, but is not recommended for asymptomatic patients having low-risk procedures. BNP or NT-proBNP may provide additive prognostic information, as elevated levels independently predict perioperative cardiac events. Routine CBC and BMP should be obtained only when clinically indicated.

Perioperative Medication Management

Beta-Blockers

Patients already taking beta-blockers chronically should continue them perioperatively, as abrupt withdrawal increases risk. New beta-blockers should not be initiated on the day of surgery. The POISE trial showed that perioperative metoprolol initiation reduced MI but increased stroke and all-cause mortality. If beta-blockers are to be started preoperatively, they should be begun days to weeks before surgery and titrated carefully, targeting a resting heart rate of 60 to 80 bpm without hypotension.

Statins

Statins should be continued perioperatively because discontinuation is associated with rebound cardiovascular events. It is reasonable to initiate statins preoperatively for patients undergoing vascular surgery, given observational benefit from their pleiotropic anti-inflammatory effects.

ACE Inhibitors/ARBs

Management of ACEi/ARBs is controversial. Holding them on the morning of surgery reduces intraoperative hypotension, while continuing them may prevent postoperative AKI. The common practice is to hold ACEi/ARBs on the morning of surgery and restart them postoperatively once the patient is euvolemic and hemodynamically stable. For patients taking these medications for heart failure, continuing may be preferable given the risk of decompensation if held.

Antiplatelet Agents

Aspirin used for primary prevention should be discontinued 7 to 10 days before surgery. For secondary prevention in patients with known CAD or prior stent, aspirin is generally continued perioperatively unless there is high bleeding risk (intracranial or spinal surgery). The POISE-2 trial showed that aspirin initiation or continuation perioperatively did not reduce MACE but increased bleeding. P2Y12 inhibitors should be held before surgery: clopidogrel for 5 days, ticagrelor for 5 days, and prasugrel for 7 days. For patients with recent coronary stents, the thrombotic risk of stopping antiplatelet therapy must be balanced against the bleeding risk, and cardiology should be involved.

Anticoagulants

Detailed bridging protocols for anticoagulants are covered in Topic 34 (Anticoagulation Reversal and Periprocedural Management).

Other Medications

Insulin management involves reducing basal insulin by 25 to 50 percent on the evening before or morning of surgery and holding short-acting insulin. Metformin should be held on the day of surgery due to concern for lactic acidosis with renal hypoperfusion and resumed when the patient is eating and renal function is stable. SGLT2 inhibitors should be held 3 to 4 days before major surgery because of the risk of euglycemic DKA. Thyroid hormone should be continued perioperatively. Stress-dose steroid protocols for patients on chronic steroids are covered in Topic 29.

Perioperative Monitoring

Troponin Surveillance

Some guidelines, including CCS 2017, recommend routine postoperative troponin monitoring for high-risk patients (RCRI of 1 or greater, age 65 or older with cardiovascular disease, age 45 or older with significant cardiovascular disease). Myocardial injury after non-cardiac surgery (MINS) refers to troponin elevation due to ischemia even without symptoms. MINS occurs in 8 to 18 percent of high-risk patients and is associated with increased 30-day mortality. The MANAGE trial found that dabigatran reduced vascular events after MINS but increased bleeding, and this is not yet standard of care. Perioperative MI is often silent, with only 35 percent of patients experiencing ischemic symptoms. Type 2 MI from supply-demand mismatch is more common than Type 1 in the perioperative setting.

Hemodynamic Monitoring

Prolonged hypotension (MAP less than 65 mmHg) and tachycardia should be avoided perioperatively. In patients already on beta-blocker therapy, perioperative heart rate control helps reduce myocardial oxygen demand.

Special Populations

Patients with Coronary Stents

Interruption of dual antiplatelet therapy represents the highest-risk scenario in these patients. Elective surgery should be delayed until the minimum DAPT duration has been completed. If surgery is urgent, aspirin should be continued, the P2Y12 inhibitor held for the shortest possible time, and the agent restarted as soon as possible postoperatively.

Patients with Heart Failure

Volume status should be optimized preoperatively. Guideline-directed medical therapy (beta-blocker, ACEi/ARB, MRA) should be continued perioperatively when possible. Patients with HFrEF and an ejection fraction below 30 percent face perioperative mortality rates 2 to 4 times higher than the general surgical population.

Patients with Valvular Heart Disease

Symptomatic severe aortic stenosis carries the highest perioperative cardiac risk. Valve replacement (TAVR or SAVR) should be considered before elective non-cardiac surgery. Asymptomatic severe aortic stenosis may allow elevated-risk surgery to proceed with invasive hemodynamic monitoring. Patients with mechanical heart valves require bridging anticoagulation as detailed in Topic 34.

<image> A stepwise clinical algorithm flowchart depicting the ACC/AHA perioperative cardiovascular evaluation pathway. Begin with "Emergency surgery?" and proceed through: active cardiac conditions assessment, surgical risk estimation (low vs elevated), functional capacity evaluation (>=4 METs vs <4 METs), and RCRI calculation. Show decision points leading to "Proceed to surgery" or "Consider further testing." Include the RCRI scoring components in a sidebar box. Use green for proceed pathways and yellow for caution/testing pathways. </image>

<image> A summary infographic of perioperative medication management displayed as a table with three columns: "Continue," "Hold," and "Controversial." The Continue column includes beta-blockers (chronic), statins, and thyroid hormones. The Hold column includes SGLT2 inhibitors, P2Y12 inhibitors, and metformin. The Controversial column includes ACE inhibitors/ARBs and aspirin, with brief annotations explaining the evidence for each decision. Use color-coded icons for each medication class. </image>

<image> A timeline diagram showing the recommended delays between coronary stent placement and elective non-cardiac surgery. Show a horizontal timeline with markers for bare-metal stent (30 days minimum with DAPT), drug-eluting stent (6-12 months minimum with DAPT), and balloon angioplasty alone (14 days). Above the timeline, indicate the risk of stent thrombosis (highest in first month, declining over time). Below, show the corresponding DAPT regimen duration. Include a decision branch for urgent surgery scenarios. </image>

Clinical Pearls

The most important step in perioperative cardiac evaluation is a thorough history and functional capacity assessment, as this alone determines most management decisions. Preoperative stress testing should not be ordered unless the result would change the surgical plan or anesthetic approach. The POISE trial taught the field that starting high-dose beta-blockers on the day of surgery is harmful, but abruptly stopping chronic beta-blockers is equally dangerous. The CARP trial showed that preoperative revascularization in stable CAD does not improve outcomes, and patients should proceed with optimized medical therapy. Most perioperative MIs are Type 2 (demand ischemia), occur postoperatively, and are often silent, so maintaining high clinical suspicion and monitoring troponins in high-risk patients is important. Functional capacity of 4 METs or greater is a reliable reassurance: if the patient can climb a flight of stairs without symptoms, extensive cardiac testing is rarely needed. Cardiology should be involved early for patients with recent coronary stents who need urgent surgery, as DAPT management in this setting is nuanced.

References

• Fleisher LA, et al. 2014 ACC/AHA Guideline on Perioperative Cardiovascular Evaluation and Management. Circulation. 2014.
• Halvorsen S, et al. 2022 ESC Guidelines on Cardiovascular Assessment and Management for Non-Cardiac Surgery. European Heart Journal. 2022.
• POISE Trial: Devereaux PJ, et al. Effects of Extended-Release Metoprolol Succinate in Patients Undergoing Non-Cardiac Surgery. Lancet. 2008.
• POISE-2 Trial: Devereaux PJ, et al. Aspirin in Patients Undergoing Non-Cardiac Surgery. NEJM. 2014.
• CARP Trial: McFalls EO, et al. Coronary Artery Revascularization Before Elective Major Vascular Surgery. NEJM. 2004.
• MANAGE Trial: Devereaux PJ, et al. Dabigatran in Patients with Myocardial Injury After Non-Cardiac Surgery. Lancet. 2018.
• Lee TH, et al. Derivation and Prospective Validation of a Simple Index for Prediction of Cardiac Risk. Circulation. 1999.

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