Dutch outcome in implantable cardioverter-defibrillator therapy extended follow up do it xl long term outcomes in a large primary prevention population

Background

International guideline recommendations are increasingly moving toward a more conservative approach regarding ICD implantation, especially in patients with non-ischemic cardiomyopathy. How does the choice to withhold ICD implantation compare to the potential procedural and device-related complications?

Purpose

To evaluate the long-term outcomes, including survival- and event rates, of the DO-IT study population across all ICD implantation indications.

Methods

This study reports the extended follow-up of the previously published Dutch Outcome in Implantable Cardioverter-Defibrillator Therapy (DO-IT) study, including patients who received a first ICD for primary prevention between September 2014 and June 2016. The design of the original study has been published previously. All centers participating in the DO-IT registry were contacted and asked to retrospectively report survival outcomes and clinical event rates up to 10 years after initial inclusion. Endpoints included overall survival, (in)appropriate ICD therapy and device-related complications.

Results

Of the initial cohort, 740 patients from 12 of 27 centers were available for this analysis. 29.6% of patients were female, the mean age was 67 ± 11 years. Ischemic cardiomyopathy (ICMP) was present in 52.8% of cases, hypertrophic CMP in 1.5%, dilated CMP in 15.0% and other non-ischemic cardiomyopathy in 28.5%. 1.6% and 0.5% of the cohort received an ICD for genetic or other reasons, respectively. For this analysis, patients not classified as having iCMP were analyzed as part of the non-ischemic cardiomyopathy (niCMP) group. Most patients received either a biventricular ICD (40.5%) or single-chamber ICD (37.3%).

After a median follow-up time of 7.54 [IQR 4.25; 8.37] years, 38.4% of the cohort died (iCMP 44.8% vs. niCMP 31.2%, p = 0.001), with cardiac-related deaths accounting for 1/3rd of these cases, most due to heart failure, while arrhythmic death had a very low incidence in both groups (iCMP n = 6 of 391, niCMP n = 2 of 349).

During follow-up a total of 157 patients (21.2%) received at least one episode of appropriate ICD therapy (iCMP 23.5 %, niCMP 18.6%, p = 0.124), see also figure 1. Appropriate therapy was delivered at an annual rate of 8.2% for patients with an iCMP and 6.5% for patients with a niCMP, while the annual rate for inappropriate therapy was 1.3% in both cohorts with iCMP and niCMP. Also 64 patients (iCMP n=31 (7.9%) vs niCMP n = 33 (9.5%)) experienced at least one complication requiring hospitalization, most frequently due to either lead displacement or lead failure.

Conclusion

Extended follow-up shows that even in modern times with more contemporary heart failure therapy, appropriate ICD therapy is frequently needed in primary prevention ICD recipients, even in the face of competing mortality risk. The high annual rate of appropriate ICD therapies in our cohort warrants reconsideration to withhold an ICD in patients with niCMP.Time until first episode of appropriateBaseline characteristics, ICD –therapy e