What is the first‑line antibiotic for surgical wound prophylaxis after an ilio‑femoral endarterectomy, including dosing and alternatives for β‑lactam allergy or MRSA risk?

Antibiotic Prophylaxis for Iliofemoral Endarterectomy

Cefazolin 2g IV administered 30-60 minutes before surgical incision is the first-line antibiotic for prophylaxis in iliofemoral endarterectomy, with redosing of 1g if the procedure exceeds 4 hours. 1, 2

Standard Dosing Protocol

• Administer cefazolin 2g IV as a slow infusion within 60 minutes before surgical incision to ensure adequate tissue concentrations throughout the vascular procedure 2, 3
• Redose with cefazolin 1g intraoperatively if surgical duration exceeds 4 hours to maintain therapeutic levels, as vascular procedures frequently extend beyond this timeframe 1, 2
• Limit prophylaxis duration to a maximum of 24 hours postoperatively, as prolonged administration provides no additional benefit and increases antibiotic resistance risk 1, 2

Evidence Supporting Cefazolin in Vascular Surgery

The evidence specifically supports cefazolin for vascular procedures based on systematic review data showing β-lactams with gram-negative activity reduce mortality and pneumonia in cardiac and vascular surgery 1. A head-to-head trial comparing cefuroxime versus cefazolin in vascular surgery demonstrated cefazolin was superior, with only 1.0% deep wound infection rate versus 2.6% with cefuroxime 4. Importantly, S. aureus isolates from vascular wounds showed greater susceptibility to cefazolin (median MIC 0.5 mcg/mL) than cefuroxime (median MIC 2.0 mcg/mL) 4.

Alternatives for β-Lactam Allergy

• For patients with documented β-lactam allergy, use vancomycin 30 mg/kg IV over 120 minutes as the preferred alternative 5, 2
• Complete vancomycin infusion ideally 30 minutes before surgical incision to ensure adequate tissue penetration 5, 2
• Clindamycin 900 mg IV slow infusion is an acceptable second alternative for β-lactam allergic patients 5, 2

MRSA Risk Considerations

Routine use of vancomycin for MRSA prophylaxis is NOT recommended unless specific high-risk criteria are met 1, 5. The evidence shows no difference in overall surgical site infection rates between glycopeptides and β-lactams in vascular surgery, and glycopeptides are associated with increased respiratory tract infections (RR 1.54) 1.

Reserve vancomycin specifically for:

• Known MRSA colonization 5
• Recent antibiotic therapy 5
• Reoperation in units with documented MRSA ecology 5
• Documented severe β-lactam allergy 5, 2

Critical Timing Considerations

Antibiotic administration timing is the most critical factor for efficacy 3. The first dose must be given within 30-60 minutes before incision, with infusion completed before tourniquet inflation if applicable 1, 3. Beginning antibiotics earlier than 60 minutes provides no benefit, while starting after incision significantly reduces effectiveness 1, 3.

Common Pitfalls to Avoid

• Do not use third-generation cephalosporins (ceftriaxone, cefotaxime) for routine prophylaxis, as they offer no advantage over cefazolin and promote resistance 1, 6
• Do not extend prophylaxis beyond 24 hours postoperatively, as this increases complications without reducing infection rates 1, 2
• Do not substitute cefuroxime for cefazolin in vascular surgery, as direct comparative data shows inferior outcomes 4
• Do not use vancomycin routinely for MRSA coverage, as no threshold of MRSA prevalence justifies switching from β-lactams to glycopeptides for prophylaxis 1