Risk for appropriate ICD intervention and complications in patients implanted after an out-hospital cardiac arrest compared to patients implanted for primary and other secondary prevention indication

Abstract Background Few data are available about patients implanted with an implantable cardioverter defibrillators (ICDs) after an out-of-hospital cardiac arrest (OHCA). In particular, it is unclear if these patients have a higher risk of appropriate device therapy than patients implanted for primary and other secondary prevention. Purpose To assess if appropriate device interventions (ATP/shocks) are higher in patients implanted after OHCA compared to patients implanted for primary and secondary prevention other than OHCA. To verify also if mortality, implantation-related complications (pneumothorax, hemothorax, hematoma, cardiac tamponade), device-related complications (lead displacement and fracture, infections) and inappropriate shocks/ATP are higher in OHCA patients compared to other patients. Methods This is a retrospective multicenter international study. All the patients implanted with an ICD between January 2015 and December 2016 in the participating centers were included. Follow-up was considered concluded in case of death or at the last follow-up available until December 2023. Patients were divided according to ICD implantation indication (secondary prevention after OHCA, other secondary prevention, primary prevention). Results 1386 patients (79% males; median age 67, IQR 59-74) from 15 centers were included with a median follow-up of 83 months: 111 patients in OHCA group, 134 in other secondary prevention group and 1141 in primary prevention group. Considering the first appropriate intervention, a significant difference among the three groups was observed (Fig.1A) and, at post-hoc comparison, the OHCA group was at higher risk than primary prevention (HR 1.51, 95%CI 1.06-2.17, p=0.02), but was at similar risk than other secondary prevention (HR 0.79, 95%CI 0.51-1.23, p=0.3). This was confirmed also after correction for age, gender, history of atrial fibrillation, aetiology and multi-comorbidity (Fig.2A). However, considering the number of appropriate interventions during follow-up, the risk of OHCA group was lower than other secondary prevention (IRR 0.28, 95%CI 0.11-0.68, p<0.01) and similar to primary prevention (IRR 0.97, 95%CI 0.47-1.96, p=0.93), also after correction for the other predictors (Fig.2B). The three groups showed no differences in survival (Fig.1B), implantation-related complication, device-related complications (Fig.1C) and inappropriate shocks/ATP. Conclusion Patients implanted with an ICD after an OHCA have a risk similar to those implanted for other secondary prevention, when considering the first appropriate intervention, but a risk similar to those implanted for primary prevention when considering the number of appropriate interventions during follow-up. Our study confirms that OHCA patients represents a peculiar population with the same chance of survival and rate of complications compared to primary and other secondary prevention patients suggesting the need of more studies to improve their long-term treatment.Figure 1 (Panel A, B and C)Figure 2 (Panel A and B)