Is an arterial duplex scan required in the imaging needed prior to Coronary Artery Bypass Grafting (CABG)?

Arterial Duplex Scan Prior to CABG: Selective Approach Based on Risk Factors

Arterial duplex ultrasound scanning is NOT routinely required prior to CABG but is strongly recommended in specific high-risk patient populations, particularly those with recent stroke/TIA history within the past 6 months. 1, 2

Indications for Carotid Duplex Ultrasound Before CABG

Strongly Recommended (Class I, Level B):

• Patients with recent (<6 months) history of TIA or stroke 1

May Be Considered (Class IIb, Level B):

• Age ≥70 years
• Multi-vessel coronary artery disease
• Concomitant lower extremity arterial disease (LEAD)
• Presence of carotid bruit
• History of peripheral vascular disease (PVD) 1, 2, 3

Not Indicated (Class III, Level C):

• Patients requiring urgent CABG with no recent stroke/TIA 1
• Routine screening in asymptomatic patients without risk factors 1

Clinical Significance and Rationale

The prevalence of significant carotid stenosis in CABG candidates ranges from 8.5% to 14.3% 4, 3. Selective screening is justified because:

1. Perioperative stroke risk is significantly higher (18.2% vs 1.7%) in patients with severe carotid stenosis (≥80%) 3
2. Peripheral vascular disease is a strong predictor of carotid stenosis (sensitivity 63.6%, specificity 83.1%) 3
3. Targeted screening in high-risk populations reduces unnecessary testing while identifying most patients with significant stenosis 1

Management Algorithm Based on Duplex Findings

If Carotid Stenosis is Detected:

• 50-99% stenosis with recent (<6 months) TIA/stroke: Consider carotid revascularization (preferably CEA) before CABG (Class IIa, Level B) 1
• 70-99% bilateral stenosis or 70-99% stenosis + contralateral occlusion: Consider carotid revascularization even in asymptomatic patients (Class IIb, Level B) 1, 2
• <50% stenosis: Carotid revascularization not recommended (Class III, Level C) 1
• 70-99% unilateral stenosis in asymptomatic patients: Routine prophylactic revascularization not recommended (Class III, Level B) 1

Important Caveats and Pitfalls

1. Timing matters: The decision about carotid revascularization should be made early enough to allow for potential intervention before CABG 2

2. Limited predictive value: Carotid duplex identifies only a minority of patients who will develop perioperative stroke, as many strokes during CABG are related to aortic atherosclerosis or hemodynamic factors rather than carotid disease 1

3. Multidisciplinary approach: Any decision regarding carotid revascularization should involve discussion within a multidisciplinary team including a neurologist (Class I, Level C) 1, 2

4. Risk of staged procedures: Staged CAS plus cardiac surgery may increase bleeding risk during CABG if performed within the DAPT period 1

By following this selective approach to arterial duplex scanning before CABG, clinicians can identify patients at highest risk for perioperative stroke while avoiding unnecessary testing in low-risk populations.