How to manage cardiac risk in patients undergoing foot and ankle surgery?

Managing Cardiac Risk in Foot and Ankle Surgery

Foot and ankle surgery is generally classified as low-risk (<1% cardiac event rate), and most patients can proceed directly to surgery with appropriate medical therapy without extensive cardiac testing. 1

Risk Stratification

Use the Revised Lee Cardiac Risk Index to quantify perioperative cardiac risk based on the following factors 2, 3, 4:

• High-risk surgery (not applicable to foot/ankle procedures)
• Ischemic heart disease (angina or prior MI)
• Heart failure
• Cerebrovascular disease (stroke/TIA)
• Insulin-dependent diabetes mellitus
• Renal dysfunction (creatinine >2 mg/dL)
• Age >75 years

Patients with 0-2 risk factors have low cardiac risk and can proceed to surgery without delay or additional testing. 3, 4 Patients with ≥3 risk factors warrant more careful evaluation, though foot/ankle surgery itself remains low-risk. 1

Preoperative Assessment

Measure vital signs (blood pressure and heart rate) and perform cardiac physical examination within 2 hours of surgery. 1 Focus specifically on:

• Signs of decompensated heart failure (elevated JVP, pulmonary rales, peripheral edema) 2
• Unstable coronary syndromes (rest angina, recent MI) 2
• Significant arrhythmias 2
• Severe valvular disease (murmurs with symptoms) 2

Assess functional capacity by asking if the patient can climb two flights of stairs without stopping due to cardiac symptoms. 2, 4 Inability to achieve 4 metabolic equivalent tasks (METs) indicates poor functional capacity and higher risk. 2, 4

Obtain preoperative laboratory studies in intermediate- and high-risk patients 1, 2:

• Complete blood count and renal function (creatinine, BUN) 1, 2
• Hemoglobin A1c in diabetic patients (target <7%) 2
• Serum albumin (hypoalbuminemia predicts complications) 2

A 12-lead ECG is recommended for patients with at least one clinical risk factor, though this is more critical for vascular surgery than foot/ankle procedures. 2

When to Delay Surgery

Delay elective foot/ankle surgery if any of the following active cardiac conditions are present 2:

• Unstable coronary syndromes (unstable angina, recent MI within 30 days)
• Decompensated heart failure (NYHA Class IV, worsening symptoms)
• Significant arrhythmias (high-grade AV block, symptomatic ventricular arrhythmias, supraventricular arrhythmias with uncontrolled rate)
• Severe valvular disease (severe aortic stenosis, symptomatic mitral stenosis)

Stabilize these conditions before proceeding with elective surgery. 2

Cardiac Testing

Routine stress testing is NOT indicated for foot/ankle surgery, even in patients with cardiac risk factors, because the surgery is low-risk. 3, 4 Stress testing does not predict which patients will have perioperative MI or death, and delays surgery by up to 3 weeks without improving outcomes. 3

Stress testing may be considered only if 4:

• The patient has poor functional capacity (<4 METs)
• The patient has ≥3 cardiac risk factors
• Test results would change perioperative medical, anesthesia, or surgical management independent of the planned surgery

Routine coronary revascularization does not reduce perioperative risk and should not be performed solely to facilitate noncardiac surgery. 3, 4

Perioperative Medical Management

Beta-Blockers

Continue beta-blockers in patients already taking them for angina, arrhythmias, or hypertension. 2, 5 Abrupt discontinuation can precipitate acute coronary syndromes. 5

Do NOT routinely start high-dose beta-blockers (e.g., metoprolol 100 mg) 2-4 hours before surgery, as this increases stroke risk (1.0% vs 0.5%) and mortality (3.1% vs 2.3%). 4

For patients with ≥1 cardiac risk factor undergoing vascular surgery (not foot/ankle surgery), consider starting low-dose beta-blocker (bisoprolol 2.5-5 mg daily) at least 30 days before surgery, titrated to heart rate <70 bpm and systolic BP ≥120 mmHg. 2, 3 This recommendation is less applicable to low-risk foot/ankle procedures.

Statins

Start or continue statins in all patients with atherosclerotic cardiovascular disease undergoing any surgery. 2, 3, 4 Statins reduce postoperative cardiovascular complications (1.8% vs 2.3% without statins) and mortality. 4

Ideally initiate statins 30 days before surgery using long-acting formulations (e.g., fluvastatin 80 mg daily or atorvastatin 40-80 mg daily). 3

Aspirin

Routine perioperative low-dose aspirin (100 mg daily) does NOT decrease cardiovascular events but does increase surgical bleeding. 4

Continue aspirin only in patients with 2:

• Recent coronary stent placement (especially drug-eluting stents within 12 months)
• Established coronary artery disease where the cardiovascular benefit outweighs bleeding risk

Discuss aspirin continuation with the surgeon, as foot/ankle surgery may have specific bleeding concerns.

ACE Inhibitors/ARBs

Consider ACE inhibitors or ARBs preoperatively in patients with heart failure and reduced ejection fraction (LVEF <40%). 2

Hold ACE inhibitors on the morning of surgery to reduce risk of intraoperative hypotension. 6 ACE inhibitors can block compensatory renin release during anesthesia, leading to refractory hypotension. 6

Restart ACE inhibitors postoperatively only after confirming euvolemia to decrease risk of perioperative renal dysfunction. 2, 6

Special Populations

Elderly Patients (≥75 years)

Age >75 years increases perioperative cardiac risk (9.5% vs 4.8% in younger adults), though this is primarily relevant for higher-risk surgeries. 4 Age alone causes only small increases in risk; greater risks come from comorbid cardiac, pulmonary, and renal disease. 2

Patients with Coronary Stents

Patients with coronary stents have significantly elevated perioperative risk (8.9% vs 1.5% without stents). 4

Elective surgery should be delayed 4:

• At least 30 days after bare-metal stent placement
• At least 12 months after drug-eluting stent placement

Continue dual antiplatelet therapy (aspirin + P2Y12 inhibitor) throughout the perioperative period if surgery cannot be delayed, accepting increased bleeding risk. Discuss with cardiology and surgery teams.

Patients with Heart Failure

Optimize volume status preoperatively. 2, 5 Beta-blockers can depress myocardial contractility and precipitate heart failure; monitor closely. 5

Careful fluid management is essential during surgery to avoid exacerbating heart failure. 2 Regional anesthesia may be preferable to general anesthesia in patients with severe LV dysfunction.

Diabetic Patients

Target hemoglobin A1c <7% to reduce complications. 2 Beta-blockers may mask hypoglycemia symptoms (tachycardia), though dizziness and sweating remain. 5

Intraoperative Considerations

Maintain normothermia throughout the procedure. 2

Control blood glucose perioperatively in diabetic patients or those with acute hyperglycemia. 2

Use volatile anesthetic agents for maintenance of general anesthesia in hemodynamically stable patients at risk for myocardial ischemia. 2

Common Pitfalls to Avoid

Do not order stress tests reflexively in patients with cardiac risk factors undergoing low-risk foot/ankle surgery—this delays surgery without improving outcomes. 3, 4

Do not start high-dose beta-blockers acutely before surgery, as this increases stroke and death risk. 4

Do not routinely discontinue beta-blockers in patients already taking them, as abrupt withdrawal can precipitate acute coronary syndromes. 5

Do not perform prophylactic coronary revascularization solely to facilitate noncardiac surgery—it does not reduce perioperative MI or death. 3, 4

Do not ignore functional capacity assessment—inability to climb two flights of stairs is more predictive of cardiac risk than many formal tests. 2, 4