Introduction: Antimicrobial envelopes reduce the incidence of cardiac implantable electronic device (CIED) infections; however, patient selection strategies are poorly defined and cost–utility data are limited.
Methods: In a preliminary internal analysis, we examined the factors associated with infection for all transvenous CIED implants, generator changes and non-infected lead interventions at a single tertiary centre from 2016 to 2019. The primary outcome was hospitalisation for device infection within 12 months. We subsequently developed a novel risk score (BLISTER) and, in a multicentre validation cohort, compared prognostic utility versus the PADIT score. Finally, both scores were tested as gatekeepers in cost–utility modelling of the TYRX antimicrobial envelope; quality-adjusted life-year (QALY) increments were extrapolated from analysis of EQ-5D-3L data for all UK patients enrolled in the WRAP-IT trial.
Results: A total of 6,035 patients underwent 7,383 procedures; CIED infection occurred in 59 individuals (0.8%). In addition to the PADIT score constituents, lead extraction (HR 3.3 [1.9–6.1]; p<0.0001), C-reactive protein >50 mg/L (HR 3.0 [1.4–6.4]; p=0.005), re-intervention within 2 years (HR 10.1 [5.6–17.9]; p<0.0001), and procedure duration over 2 hours (HR 2.6 [1.6–4.1]; p=0.001) were independent predictors of infection, and were incorporated into the novel BLISTER score. In a validation cohort comprising 2,701 additional patients from three tertiary centres, BLISTER demonstrated superior prognostic utility versus PADIT (AUC 0.83 vs 0.73; p=0.01). The optimum cost–utility model assigned TYRX envelopes to all patients with a BLISTER score ≥6, and predicted a reduction in infections (0.55% versus 0.8%; p=0.033; number needed to treat 63) with a cost per QALY gained of £24,581.
Conclusions: The BLISTER score was a powerful predictor of infection in a heterogeneous CIED population and may facilitate cost-effective TYRX envelope allocation.
