Is an arterial duplex scan recommended prior to Coronary Artery Bypass Grafting (CABG) or open heart surgery such as Surgical Aortic Valve Replacement (SAVR)?

Arterial Duplex Scan Recommendation Prior to CABG or Open Heart Surgery

Routine arterial (carotid) duplex scanning is not recommended for all patients undergoing CABG or open heart surgery, but is reasonable for selected high-risk patients based on specific clinical criteria.

Risk-Stratified Screening Approach

For CABG Surgery - Class IIa Recommendations (Reasonable to Perform)

Carotid duplex ultrasound screening is reasonable before elective CABG in patients with ANY of the following high-risk features: 1, 2

• Age >65 years (some guidelines specify ≥70 years)
• Left main coronary stenosis
• Peripheral arterial disease (PAD)
• History of stroke or TIA
• Carotid bruit on examination
• History of cigarette smoking
• Diabetes mellitus
• Hypertension

For Valve Surgery (SAVR) Without CABG - Uncertain Appropriateness

The evidence is less clear for isolated valve procedures: 1

• With atherosclerotic disease elsewhere (PAD, CAD, AAA) or history of neck irradiation ≥10 years ago: Uncertain appropriateness (score 6/9)
• With atherosclerotic risk factors present: Uncertain appropriateness (score 6/9)
• Without atherosclerotic risk factors: Uncertain appropriateness (score 4/9)

Rationale for Selective Rather Than Universal Screening

Evidence Against Universal Screening

The overall perioperative stroke rate after cardiac surgery is low (1.4-3.8%), and most strokes are NOT related to carotid stenosis: 1, 3

• Only 60% of territorial infarctions can be attributed to carotid disease alone 1
• 55% of strokes occur after uneventful recovery from anesthesia, attributed to atrial fibrillation, low cardiac output, or hypercoagulopathy 1
• In one study, only 3 of 21 postoperative stroke patients had hemodynamically significant carotid lesions (>70%) 3
• Universal screening resulted in an estimated net cost of $378,918 with minimal clinical benefit 3

Prevalence of Significant Carotid Disease

When screening is performed in cardiac surgery patients, the prevalence of significant carotid stenosis (≥50%) ranges from 7.7-16.3%: 4, 5, 6

• Among screened patients, only 2.9-3.3% have unilateral severe stenosis (70-99%) 6
• Only 0.7-1.6% have bilateral severe stenosis 6

Clinical Decision Algorithm

Step 1: Assess for Absolute Indications (Class I - Must Perform)

Perform carotid duplex if patient has: 1

• Recent neurological symptoms (stroke, TIA, amaurosis fugax within 6 months)
• Known symptomatic carotid disease

Step 2: Assess for High-Risk Features (Class IIa - Should Perform)

Perform carotid duplex if patient has ANY of: 1, 2

• Age >65 years
• Left main coronary stenosis or 3-vessel disease 4
• Peripheral arterial disease 4, 5
• Carotid bruit 5
• History of prior stroke/TIA (even if remote)
• Smoking history
• Diabetes mellitus

Step 3: Low-Risk Patients

Do NOT routinely screen patients who: 3, 6

• Are younger (<65 years)
• Have no atherosclerotic risk factors
• Have no history of cerebrovascular symptoms
• Have no carotid bruit
• Have no peripheral vascular disease

Management of Identified Carotid Stenosis

Symptomatic Patients (Recent TIA/Stroke Within 6 Months)

Carotid revascularization (CEA or CAS with embolic protection) is reasonable for stenosis >80% (some guidelines use >50%): 1, 2

• CEA is preferred over CAS for symptomatic disease 1, 2
• Timing (staged vs. simultaneous with cardiac surgery) should be determined by multidisciplinary team 1

Asymptomatic Patients

The safety and efficacy of carotid revascularization before or concurrent with cardiac surgery in asymptomatic patients is NOT well established (Class IIb - Uncertain): 1

• May be considered for bilateral severe stenosis (70-99%) or unilateral severe stenosis with contralateral occlusion 1
• No convincing evidence that intervention in asymptomatic stenosis improves outcomes 1

Critical Pitfalls to Avoid

Common Errors

• Do not perform universal screening on all cardiac surgery patients - this is not cost-effective and does not improve outcomes 3, 6
• Do not assume carotid stenosis predicts stroke risk - patient comorbidities and preoperative duplex velocities are not predictive of postoperative stroke 3
• Do not routinely revascularize asymptomatic carotid stenosis before cardiac surgery - evidence of benefit is lacking 1

Important Nuances

• Carotid bruit correlates more with systemic atherosclerosis than with significant carotid stenosis, but still warrants investigation 7
• Doppler can overestimate stenosis with contralateral disease or underestimate critical high-grade stenosis 7
• Most postoperative strokes occur in the anterior circulation (69.2%), but 15.4% occur in posterior circulation and 15.4% in both territories 3

Multidisciplinary Team Approach

A multidisciplinary team (cardiologist, cardiac surgeon, vascular surgeon, neurologist) is recommended for patients with clinically significant carotid disease planning CABG (Class I recommendation): 1, 2