Factors affecting ventriculoperitoneal shunt revision: a post hoc analysis of the British Antibiotic and Silver Impregnated Catheter Shunt multicenter randomized controlled trial

OBJECTIVE The British Antibiotic and Silver Impregnated Catheter Shunt (BASICS) trial established level I evidence of the superiority of antibiotic-impregnated catheters in the prevention of infection of newly implanted ventriculoperitoneal shunts (VPSs). A wealth of patient, shunt, and surgery-specific data were collected from trial participants beyond that of the prespecified trial objectives. METHODS This post hoc analysis of the BASICS survival data explores the impact of patient age, hydrocephalus etiol-ogy, catheter type, valve type, and previous external ventricular drain on the risk of infection or mechanical failure. Time to failure was analyzed using Fine and Gray survival regression models for competing risk. RESULTS Among 1594 participants, 75 patients underwent revision for infection and 323 for mechanical failure. Multi -variable analysis demonstrated an increased risk of shunt infection associated with patient ages < 1 month (subdistribu-tion hazard ratio [sHR] 4.48, 95% CI 2.06-9.72; p < 0.001) and 1 month to < 1 year (sHR 2.67, 95% CI 1.27-5.59; p = 0.009), as well as for adults with posthemorrhagic hydrocephalus (sHR 2.75, 95% CI 1.21-6.26; p = 0.016). Age >= 65 years was found to be independently associated with reduced infection risk (sHR 0.26, 95% CI 0.10-0.69; p = 0.007). Antibiotic-impregnated catheter use was also associated with reduced infection risk (sHR 0.43, 95% CI 0.22-0.84; p = 0.014). Independent risk factors predisposing to mechanical failure were age < 1 month (sHR 1.51, 95% CI 1.03-2.21; p = 0.032) and 1 month to < 1 year (sHR 1.31, 95% CI 0.95-1.81; p = 0.046). Age >= 65 years was demonstrated to be the only independent protective factor against mechanical failure risk (sHR 0.64, 95% CI 0.40-0.94; p = 0.024).CONCLUSIONS Age is the predominant risk for VPS revision for infection and/or mechanical failure, with neonates and infants being the most vulnerable.