What are the recommendations for a patient with peripheral vascular disease undergoing Coronary Artery Bypass Grafting (CABG)?

CABG in Patients with Peripheral Vascular Disease

Patients with peripheral vascular disease undergoing CABG face significantly elevated perioperative risks and require specific preoperative screening, surgical planning modifications, and intensified perioperative management to reduce morbidity and mortality.

Preoperative Risk Assessment

Carotid Artery Screening

• Perform duplex ultrasound (DUS) in all patients with recent (<6 months) history of TIA or stroke 1, 2
• Consider DUS screening in patients with: 1, 2
  • Age ≥70 years
  • Multivessel coronary artery disease
  • Audible carotid bruit on examination
  • History of smoking
  • Left main coronary stenosis
• Skip carotid screening only if CABG is urgent and no recent neurological symptoms occurred 1
• This targeted approach identifies most patients with significant stenosis while reducing unnecessary testing by 40% 2

Lower Extremity Assessment

• Screen for lower extremity artery disease (LEAD) before saphenous vein harvesting 1
• Perform at minimum clinical examination and ankle-brachial index (ABI) measurement 1
• This screening is critical because saphenous vein harvest can cause wound healing complications in severe LEAD 1

Management of Identified Carotid Stenosis

Recent Stroke/TIA (<6 months)

• Perform carotid revascularization in patients with 50-99% stenosis 1
• Carotid endarterectomy (CEA) is the preferred method over carotid artery stenting (CAS) 1
• Do not revascularize stenosis <50% 1

Asymptomatic Patients

• Do not perform routine prophylactic carotid revascularization for 70-99% stenosis 1
• Consider revascularization only in: 1
  • Bilateral 70-99% stenoses
  • 70-99% stenosis with contralateral occlusion
• All decisions must involve multidisciplinary team discussion including a neurologist 1

Surgical Planning Modifications

Conduit Selection

• Spare the great saphenous vein whenever possible for potential future peripheral bypass 1
• Use radial artery or internal mammary artery as alternative conduits 1
• The autologous saphenous vein is the conduit of choice for future femoro-popliteal and infra-popliteal bypass 1
• Success of peripheral revascularization in complex lesions strongly depends on availability of autologous venous segments 1

Intraoperative Considerations

• Maintain adequate mean arterial pressure during cardiopulmonary bypass (CPB) 1
• Monitor peripheral oxygen saturation in patients with chronic limb-threatening ischemia (CLTI) during CPB 1
• Consider off-pump CABG when feasible to avoid hemodynamic instability from CPB 1
• CPB causes mean arterial pressure drop and loss of pulsatile flow, risking worsening of CLTI 1

Perioperative Medical Management

Antiplatelet Therapy

• Continue low-dose aspirin (≤160 mg daily) throughout the perioperative period 3
• Aspirin reduces perioperative myocardial infarction, acute renal injury, and mortality without increasing bleeding risk 3
• For patients on dual antiplatelet therapy, delay CABG: 3
  • 5 days after stopping clopidogrel
  • 3 days after stopping ticagrelor
  • 7 days after stopping prasugrel
• Resume P2Y12 antagonist postoperatively for 12 months in patients with recent acute coronary syndrome or coronary stent 3

Risk Factor Control

• Implement strict glycemic control with continuous intravenous insulin infusion perioperatively 1
• Aggressive glucose management reduces deep sternal wound infection risk 1
• Optimize diabetes control in patients with CLTI 1

Postoperative Surveillance

Immediate Monitoring

• Actively monitor for compartment syndrome caused by ischemia-reperfusion injury during CPB 1
• Watch for neurological complications, which occur at 2.8-fold higher rates in PVD patients 4
• Monitor for pulmonary complications (1.4-fold increased risk) 5
• Assess for low cardiac output (1.3-fold increased risk) 5

Cardiac Rehabilitation

• Recognize that coexisting LEAD may complicate cardiac rehabilitation programs 1
• Adjust exercise protocols based on peripheral arterial limitations 1

Expected Outcomes and Prognostic Factors

Perioperative Risk

• Overall major complication rate is 12% in PVD patients versus 6.1% in non-PVD patients 4
• Neurological complications show the greatest differential (2.8-fold increase) 4
• Arrhythmias requiring treatment occur at 1.7-fold higher rates 5
• Renal complications occur in approximately 7% of patients 6

Long-term Outcomes

• PVD patients have 3-fold higher risk of subsequent cardiovascular events after CABG 1
• Age, diabetes, end-stage renal disease, and peripheral vascular disease independently predict increased long-term mortality 6
• Higher left ventricular ejection fraction is protective (hazard ratio 0.78 per 10% increase) 6

Critical Pitfalls to Avoid

• Never harvest saphenous vein without screening for LEAD - this can cause limb-threatening wound complications 1
• Never skip carotid screening in patients with recent neurological symptoms - stroke risk increases to 9% with significant stenosis 2
• Never perform routine prophylactic carotid revascularization in asymptomatic patients - evidence shows no benefit 1
• Never allow mean arterial pressure to drop excessively during CPB in CLTI patients - this worsens limb ischemia 1