Surgical Site Infection after Arterial Intervention with a Groin Incision

To investigate surgical site infection (SSI) statistics after arterial interventions requiring a groin incision (a known risk factor for SSI); including the influence of therapeutic vs prophylactic antibiotics, medical comorbidities associated with SSI, causative microbiology, and treatment outcomes. A 1-year (2009) retrospective, consecutive-case audit of 372 lower limb arterial interventions (bypass grafting, n = 236; AAA, stent graft, n = 86; endarterectomy/repair, n = 50) requiring a groin incision. Occurrence of SSI within 30 days was correlated with age, gender, body mass index, procedural therapeutic (active infection at time of procedure) vs prophylactic (24 hours) antibiotic administration, medical comorbidities (diabetes, renal insufficiency, coronary artery disease), and the presence of methicillin-resistant Staphylococcus aureus (MRSA) nasal colonization. In the prophylactic patient group (n = 311), the effect of adding an MRSA antibiotic (vancomycin, 15-20 mg/kg - 2 doses; daptomycin, 6 mg/kg - 1-dose) to cephalosporin prophylaxis on SSI rate was analyzed. The overall SSI rate was 15%; higher (P < .001) in patients receiving therapeutic (29%; 18 of 61) vs prophylactic (12%; 38 of 311) antibiotics. Nasal MRSA colonization was associated with ×2 increase in SSI (37% vs 16%; P < .01). SSI was lowest after open/EVAR AAA repair (5%) compared to arterial bypass (21%) or endarterectomy/repair (20%) procedures. The majority (64%) of SSIs were caused by gram + bacteria with MRSA isolated from 37% of all positive cultures. The SSI rate in patients receiving prophylactic antibiotics was 19% in the cephalosporin (cefazolin or cefepime) group, 13% in the vancomycin + cephalosporin group; and 6% in the daptomycin + cefepime group (P < .01). The frequency of MRSA SSI was similar (P = .1) in patients receiving daptomycin (1.3%) compared to the other prophylactic antibiotic regimens (4.8%). Overall, 41 (73%) of 56 patients with SSI required surgical therapy to achieve wound healing with mean LOS increase of 12 days in SSI group. Outcomes at 30 days included 1.3% (4 patients) mortality and one prosthetic graft excised for infection. Diabetes was associated with increased SSI (P < .04) while age, gender, CAD, BMI, or renal insufficiency were not predictive of SSI. This audit demonstrated one in seven patients develops SSI after arterial intervention involving the femoral artery. SSI risk was higher in diabetics, after arterial bypass, with required therapeutic antibiotics, and when nasal MRSA colonization was present. The most common bacterial isolate was MRSA. The addition of a single-dose of daptomycin (bactericidal to gram + organism including MRSA) to a cephalosporin prophylaxis regimen significantly reduced SSI. Given the trend to mandated hospital reporting of wound infection rates to consumers, these SSI statistics are relevant and indicate an urgent need to develop wound care strategies to augment primary healing and the prevention of biofilm-mediated infection.