Longevity of implantable cardioverter defibrillators: a comparison among manufacturers and over time.

AIMS: Longevity of implantable cardioverter defibrillators (ICDs) is crucial for patients and healthcare systems as replacements impact on infection rates and cost-effectiveness. Aim was to determine longevity using very large databases of two teaching hospitals with a high number of replacements and a rather homogeneous distribution among manufacturers. METHODS AND RESULTS: The study population consists of all patients in whom an ICD was inserted in. All ICD manufacturers operating in Switzerland and the Netherlands and all implanted ICDs were included. Implantable cardioverter defibrillator replacements due to normal battery depletion were considered events, and other replacements were censored. Longevity was assessed depending on manufacturers, pacing mode, implant before/after 2006, and all parameters combined. We analysed data from 3436 patients in whom 4881 ICDs [44.2% VVI-ICDs, 27.4% DDD-ICDs, 26.3% cardiac resynchronization therapy (CRT)-ICDs, 2.0% subcutaneous ICDs] were implanted. The four major manufacturers had implant shares between 18.4 and 31.5%. Replacement due to battery depletion (27.4%) was performed for 1339 ICDs. Patient survival at 5 years was 80.1%. Longevity at 5 years improved in contemporary compared with elderly ICDs [63.9-80.6% across all ICDs, of 73.7-92.1% in VVIs, 58.2-76.1% in DDDs, and of 47.1-66.3% in CRT defibrillators, all P value < 0.05]. Remarkable differences were seen among manufacturers, and those with better performance in elderly ICDs were not those with better performance in contemporary ones. CONCLUSION: Implantable cardioverter defibrillator longevity increased in contemporary models independent of manufacturer and pacing mode. Still, significant differences exist among manufacturers. These results might impact on device selection.

Inappropriate shocks in the subcutaneous ICD: Incidence, predictors and management.

BACKGROUND: The entirely subcutaneous implantable cardioverter-defibrillator (S-ICD) eliminates the need for transvenous leads, and therefore has the potential to improve lead-longevity and reduce lead-related complications. The S-ICD has a morphology-based sensing algorithm of which inappropriate shocks have been reported. METHODS: We analyzed the incidence, predictors and management of inappropriate shocks in the EFFORTLESS S-ICD Registry, which collects S-ICD implantation information and follow-up data from clinical centers in Europe and New Zealand. RESULTS: During a follow-up of 21 ± 13 months, 48 out of 581 S-ICD patients (71% male, age 49 ± 18 years) experienced 101 inappropriate shocks (8.3%). The most common cause was cardiac signal oversensing (73%), such as T-wave oversensing. Eighteen shocks (18%) were due to supraventricular tachycardias (SVT), of which 15 occurred in the shock-only zone. Cox-proportional hazard modeling using time-dependent covariates demonstrated that patients with a history of atrial fibrillation (HR 2.4) and patients with hypertrophic cardiomyopathy (HR 4.6) had an increased risk for inappropriate shocks, while programming the primary vector for sensing (from xyphoid to V6) reduced the risk. Reprogramming or optimization of SVT treatment after the first clinical event of inappropriate shock was successful in preventing further inappropriate shocks for cardiac oversensing and SVT events. CONCLUSIONS: Inappropriate shocks, mainly due to cardiac oversensing, occurred in 8.3% of the S-ICD patients. Patients with hypertrophic cardiomyopathy or a history of atrial fibrillation were at increased risk, warranting specific attention for sensing and programming in this population.

The cost-effectiveness of primary prophylactic implantable defibrillator therapy in patients with ischaemic or non-ischaemic heart disease: a European analysis.

AIMS: It remains unclear whether primary prophylactic implantable cardioverter-defibrillator (ICD) therapy is cost-effective compared with a 'no ICD strategy' in the European health care setting. We performed a cost-effectiveness analysis for a cohort of patients with a left ventricular ejection fraction <40% and ischaemic or non-ischaemic heart disease. METHODS AND RESULTS: A Markov decision analytic model was used to evaluate long-term survival, quality-adjusted life years (QALYs), and lifetime costs for a cohort of patients with a reduced left ventricular function without previous arrhythmias, managed with a prophylactic ICD. Input data on effectiveness were derived from a meta-analysis of primary prophylactic ICD-only therapy randomized trials, from a prospective cohort study of ICD patients, from a health care utilization survey, and from the literature. Input data on costs were derived from a micro-cost analysis. Data on quality-of-life were derived from the literature. Deterministic and probabilistic sensitivity analysis was performed to assess the uncertainty. Probabilistic sensitivity analysis demonstrated a mean lifetime cost of €50 685 ± €4604 and 6.26 ± 0.64 QALYs for patients in the 'no ICD strategy'. Patients in the 'ICD strategy' accumulated €86 759 ± €3343 and an effectiveness of 7.08 ± 0.71 QALYs yielding an incremental cost-effectiveness ratio of €43 993/QALY gained compared with the 'no ICD strategy'. The probability that ICD therapy is cost-effective was 65% at a willingness-to-pay threshold of €80 000/QALY. CONCLUSION: Our results suggest that primary prophylactic ICD therapy in patients with a left ventricular ejection fraction <40% and ischaemic or non-ischaemic heart disease is cost-effective in the European setting.

Poor health status and distress in cardiac patients: the role of device therapy vs. underlying heart disease.

AIMS: Implantable cardioverter defibrillator (ICD) therapy, which includes the risk of shocks, is considered the primary culprit of reductions in patient reported outcomes (PROs; e.g. health status and distress), thereby negating the role of underlying disease severity. We examined the relative influence of living with an ICD vs. congestive heart failure (CHF) on PROs and compared (i) ICD patients without CHF (ICD only), (ii) CHF patients without an ICD (CHF-only), and (iii) CHF patients with an ICD (ICD + CHF). METHODS AND RESULTS: Separate cohorts of ICD and CHF patients (N = 435; 75% men) completed PROs at baseline, 6 and 12 months. Groups differed on physical health status only at baseline (F((2,415)) = 7.15, P = 0.001) and on anxiety at 12 months (F((2,415)) = 4.04, P = 0.01); ICD + CHF patients had the most impaired physical health status but the lowest anxiety level followed by the ICD only and CHF only patients. Congestive heart failure only patients had the most impaired mental health status and reported the highest level of anxiety as compared to the ICD only (P < 0.001) and ICD + CHF groups (P = 0.009), while the two latter groups did not differ. The effect sizes ranged from very small (0.03) to moderate-large (0.69). Groups did not differ in depression scores. CONCLUSION: Congestive heart failure patients reported worse PROs as compared to ICD patients, although the magnitude of the differences was relatively small. This suggests that the well being of patients is not necessarily negatively influenced by the implantation of an ICD, and that underlying heart disease may have at least an equal if not greater influence on PROs.

Evaluation oF FactORs ImpacTing CLinical Outcome and Cost EffectiveneSS of the S-ICD: design and rationale of the EFFORTLESS S-ICD Registry.

BACKGROUND: Leads in and on the heart of the transvenous implantable cardioverter defibrillator (ICD) form the Achilles' heel of this system due to potential for peri- and postimplant complications. The S-ICD is a newer generation of the ICD that does not require leads on the heart or in the vasculature. We present the rationale and study design of the Evaluation oF FactORs ImpacTing CLinical Outcome and Cost EffectiveneSS of the S-ICD (EFFORTLESS S-ICD) Registry which was designed to evaluate the long-term performance of the S-ICD including patient quality of life and long-term resource utilization. METHODS: The Registry is an observational, nonrandomized, standard of care evaluation to be conducted at approximately 50 investigational centers in Europe and New Zealand where the S-ICD is approved for use and distribution. Clinical Registry endpoints include perioperative (30 days postimplant) complication-free rate, 360-day complication-free rate, and percentage of inappropriate shocks for atrial fibrillation and supraventricular ventricular tachyarrhythmia. Other endpoints include patient-reported outcomes (e.g., quality of life) and hospital personnel implant and follow-up experience with the S-ICD system. CONCLUSIONS: Results from EFFORTLESS will build on and expand the initial published experience with the S-ICD, which demonstrated that the device successfully and consistently detects and treats episodes of sustained ventricular tachyarrhythmias. The Registry will also evaluate the patients' perspective of how it is to live with an S-ICD as compared to a contemporary transvenous system and track the experience of implanting physicians and personnel performing patient follow-up with a completely subcutaneous system.

Analysis of implantable defibrillator longevity under clinical circumstances: implications for device selection.

INTRODUCTION: Information about implantable cardioverter-defibrillator (ICD) longevity is mostly calculated from measurements under ideal laboratory conditions. However, little information about longevity under clinical circumstances is available. This survey gives an overview on ICD service times and generator replacements in a cohort of consecutive ICD patients. METHODS: Indications for replacement were classified as a normal end-of-service (EOS), premature EOS, system malfunction, infection and device advisory, or recall actions. From the premature and normal EOS group, longevity from single-chamber (SC), dual-chamber (DC), and cardiac resynchronization therapy defibrillator (CRT-D), rate-responsive (RR) settings, high output (HO) stimulation, and indication for ICD therapy was compared. Differences between brands were compared as well. RESULTS: In a total of 854 patients, 203 ICD replacements (165 patients) were recorded. Premature and normal EOS replacements consisted of 32 SC, 98 DC and 24 CRT-D systems. Longevity was significantly longer in SC systems compared to DC and CRT-D systems (54 +/- 19 vs. 40 +/- 17 and 42 +/- 15 months; P = 0.008). Longevity between non-RR (n = 143) and RR (n = 11) settings was not significantly different (43 +/- 18 vs. 45 +/- 13 months) as it also was not for HO versus non-HO stimulation (43 +/- 19 vs. 46 +/- 17 months). Longevity of ICDs was not significantly different between primary and secondary prevention (42 +/- 19 vs. 44 +/- 18 months). The average longevity on account of a device-based EOS message was 43 +/- 18 months. Average longevity for Biotronik (BIO, n = 72) was 33 +/- 10 months, for ELA Medical (ELA, n = 12) 44 +/- 17 months, for Guidant (GDT, n = 36) 49 +/- 12 months, for Medtronic (MDT, n = 29) 62 +/- 22 months, and for St. Jude Medical (SJM, n = 5) 31 +/- 9 months (P < 0.001). CONCLUSION: SC ICD generators had a longer service time compared to DC and CRT-D systems. No influence of indication for ICD therapy and HO stimulation on generator longevity was observed in this study. MDT ICDs had the longest service time.