What is the recommended preoperative evaluation for a patient with a coronary artery calcium score of 550 undergoing hip replacement surgery?

Preoperative Cardiac Evaluation for Hip Replacement with Calcium Score 550

A patient with a coronary artery calcium score of 550 undergoing elective hip replacement should proceed directly to surgery without additional cardiac testing, as this represents intermediate-risk surgery in a patient who likely has low-to-moderate clinical cardiac risk, and routine preoperative stress testing or coronary angiography does not improve outcomes. 1

Risk Stratification Approach

Calculate Clinical Cardiac Risk First

• Use the Revised Cardiac Risk Index (RCRI) as your primary risk stratification tool to determine if the patient has 0-1 risk factors (low risk, <1% MACE) or ≥2 risk factors (elevated risk, ≥1% MACE). 1, 2
• RCRI factors include: history of ischemic heart disease, cerebrovascular disease, heart failure, insulin-dependent diabetes, chronic kidney disease (creatinine >2 mg/dL), and high-risk surgery (which hip replacement is NOT). 1, 2
• Hip replacement is classified as intermediate-risk surgery (1-5% risk of MACE), not high-risk surgery. 1

Interpret the Calcium Score in Context

• A calcium score of 550 indicates significant coronary atherosclerotic burden and places the patient at increased long-term cardiovascular risk. 1, 3
• However, the calcium score alone does NOT dictate the need for preoperative cardiac testing - clinical risk factors and functional capacity are more important for perioperative decision-making. 1
• Calcium scores ≥400 are associated with higher cardiovascular event rates (approximately 2-4% annually in primary prevention populations), but this is still lower than the threshold that would mandate coronary revascularization before elective surgery. 1, 3

Functional Capacity Assessment

Assess functional capacity using a structured tool like the Duke Activity Status Index (DASI) or by asking if the patient can climb 2 flights of stairs without symptoms. 1, 2

• If functional capacity is ≥4 METs (can climb 2 flights of stairs): Proceed directly to surgery regardless of calcium score. 1, 2, 4
• If functional capacity is <4 METs or unknown: Consider whether additional testing would change management (see below). 1, 2

When Additional Testing is NOT Indicated

Routine preoperative stress testing, echocardiography, or coronary angiography should NOT be performed in the following scenarios: 1, 5

• Asymptomatic patients with good functional capacity (≥4 METs), even with elevated calcium scores. 1
• Patients with RCRI 0-1 (low clinical risk), regardless of calcium score. 1, 2
• Routine coronary revascularization before noncardiac surgery does not reduce perioperative risk and should not be pursued without indications independent of the planned surgery. 1, 4

When Additional Testing MAY Be Considered

Pharmacological stress testing (dobutamine stress echo or myocardial perfusion imaging) may be reasonable ONLY if: 1, 2

• RCRI ≥2 (elevated clinical risk) AND
• Poor functional capacity (<4 METs) or unknown functional capacity AND
• The test results would change perioperative management (e.g., lead to coronary revascularization for indications independent of surgery, change surgical approach, or alter anesthetic management). 1, 2

Important caveat: Even in patients with RCRI ≥2 and poor functional capacity, if the test results would NOT change management, testing should be avoided. 1

Recommended Preoperative Workup

Essential Baseline Testing

• 12-lead ECG: Reasonable in all elderly patients with hip fracture or known cardiovascular disease. 1
• Complete blood count and electrolytes: Required routinely before hip surgery. 1
• BNP or NT-proBNP: May be reasonable for additional risk stratification in patients ≥65 years or with significant cardiovascular disease, though this is more strongly recommended in Canadian guidelines than US guidelines. 1, 5

Echocardiography Indications

Preoperative echocardiography is indicated ONLY if: 1

• New dyspnea or physical examination findings of heart failure. 1
• Known heart failure with worsening symptoms or change in clinical status. 1
• Routine preoperative echocardiography in asymptomatic stable patients is NOT recommended, even with elevated calcium scores. 1, 6

Perioperative Medical Management

Medications to Continue

• Beta-blockers: Continue in patients already taking them chronically (Class I recommendation). 1, 2, 7
• Statins: Continue in patients currently taking statins (Class I recommendation). 1, 4
• ACE inhibitors/ARBs: Continuation is reasonable perioperatively, though withholding 24 hours before surgery may be considered to limit intraoperative hypotension (Class IIa/IIb). 1, 7, 5

Medications to Avoid or Use Cautiously

• Do NOT initiate high-dose beta-blockers (e.g., metoprolol 100 mg) 2-4 hours before surgery - this increases stroke and mortality risk. 4
• Do NOT routinely use aspirin for perioperative cardiovascular protection unless the patient has a recent coronary stent or will undergo carotid endarterectomy - aspirin increases bleeding without reducing cardiovascular events. 4, 5

Medications to Consider Starting

• Statins: Should be considered preoperatively in patients with atherosclerotic cardiovascular disease (which a calcium score of 550 indicates) undergoing vascular surgery, and may be reasonable for other surgeries. 4

Postoperative Monitoring

Measure daily troponin for 48-72 hours after surgery in patients with: 5

• Elevated preoperative BNP/NT-proBNP, OR
• RCRI ≥1, OR
• Age ≥65 years, OR
• Age 45-64 with significant cardiovascular disease. 5

Common Pitfalls to Avoid

• Do not delay surgery for cardiac testing unless there are acute cardiac symptoms or the patient would require coronary revascularization independent of the planned surgery. 1
• Do not assume a high calcium score automatically requires stress testing - clinical risk and functional capacity are more important for perioperative decision-making. 1
• Do not perform preoperative coronary revascularization solely to "clear" the patient for surgery - this does not improve perioperative outcomes. 1, 4
• Ensure clear communication about which medications to continue or withhold on the morning of surgery. 7
• Recognize that preoperative echocardiography does not reduce time to surgery or improve outcomes in hip fracture patients, even those with prior coronary interventions. 6