Review of the registry's fourth year, incorporating lead data and pediatric ICD procedures, and use as a national performance measure

Cost effectiveness of implantable cardioverter defibrillators for 1.5 primary prevention of sudden cardiac arrest in China: an analysis from the Improve SCA study

OBJECTIVES

Implantable cardioverter defibrillator (ICDs) for primary prevention (PP) of sudden cardiac arrest (SCA) is underutilized in developing countries. The Improve SCA study has identified a subset of 1.5 primary prevention (1.5PP) patients with a higher risk of SCA and a significant mortality benefit from ICD therapy. From the perspective of China's healthcare system, we evaluated the cost-effectiveness of ICD therapy vs. no ICD therapy among 1.5PP patients with a view to informing clinical and policy decisions.

METHODS

A published Markov model was adjusted and verified to simulate the course of the disease and describe different health states of 1.5PP patients. The patient characteristics, mortality, utility and complication estimates were obtained from the Improve SCA study and other literature. Cost inputs were sourced from government tender prices, medical service prices and clinical experts' surveys in 9 Chinese public hospitals. For both ICD and no ICD therapy, the total medical costs and quality-adjusted life-years (QALYs) were modelled over a lifetime horizon and the incremental cost-effectiveness ratio (ICER) was calculated. Deterministic and probabilistic sensitivity analyses were performed to assess the uncertainty of the model parameters. We used the willingness-to-pay (WTP) threshold recommended by China Guidelines for Pharmacoeconomic Evaluations, one to three times China's GDP per capita (CNY85,698-CNY257,094) in 2022 Chinese Yuan.

RESULTS

The incremental cost effectiveness ratio (ICER) of ICD therapy compared to no ICD therapy is 139,652 CNY/QALY, which is about 1-2 times China's GDP per capita. The probability that ICD therapy is cost effective was 92.1%. Results from sensitivity analysis supported the findings of the base case.

CONCLUSIONS

ICD therapy compared to no ICD therapy is cost-effective for the 1.5PP patients in China.

Automatic measurement of short-term variability of repolarization to indicate ventricular arrhythmias in a porcine model of cardiac ischaemia

AIMS

An automated method for determination of short-term variability (STV) of repolarization on intracardiac electrograms (STV-ARIauto) has previously been developed for arrhythmic risk monitoring by cardiac implantable devices, and has proved effective in predicting ventricular arrhythmias (VA) and guiding preventive high-rate pacing (HRP) in a canine model. Current study aimed to assess (i) STV-ARIauto in relation to VA occurrence and secondarily (ii-a) to confirm the predictive capacity of STV from the QT interval and (ii-b) explore the effect of HRP on arrhythmic outcomes in a porcine model of acute myocardial infarction (MI).

METHODS AND RESULTS

Myocardial infarction was induced in 15 pigs. In 7/15 pigs, STV-QT was assessed at baseline, occlusion, 1 min before VA, and just before VA. Eight of the 15 pigs were additionally monitored with an electrogram catheter in the right ventricle, underwent echocardiography at baseline and reperfusion, and were randomized to paced or control group. Paced group received atrial pacing at 20 beats per min faster than sinus rhythm 1 min after occlusion. Short-term variability increased prior to VA in both STV modalities. The percentage change in STV from baseline to successive timepoints correlated well between STV-QT and STV-ARIauto. High-rate pacing did not improve arrhythmic outcomes and was accompanied by a stronger decrease in ejection fraction.

CONCLUSION

STV-ARIauto values increase before VA onset, alike STV-QT in a porcine model of MI, indicating imminent arrhythmias. This highlights the potential of automatic monitoring of arrhythmic risk by cardiac devices through STV-ARIauto and subsequently initiates preventive strategies. Continuous HRP during onset of acute MI did not improve arrhythmic outcomes.

Left ventricular lead implantation failure in an unselected nationwide cohort

BACKGROUND

Left ventricular (LV) lead implantation is often the most challenging aspect of cardiac resynchronization therapy (CRT) procedures; early studies reported implant failure rates in ∼10% of cases.

OBJECTIVE

The purpose of this study was to define rates, reasons for, and factors independently associated with LV lead implant failure.

METHODS

We studied patients with left bundle branch block and ejection fraction ≤ 35% who underwent planned de novo transvenous CRT implantation (2010-2016) and were reported to the National Cardiovascular Data Registry ICD Registry. Independent predictors of LV lead implant failure were determined using logistic regression; age, sex, and variables with a univariable P value of <.15 were considered for inclusion in the model.

RESULTS

Of the 111,802 patients who underwent a planned CRT procedure, 3.6% of patients (n = 3979) had LV lead implant failure. Reasons for implant failure included venous access (7.5%), coronary sinus access (64.3%), tributary vein access (13.5%), coronary sinus dissection (7.6%), unacceptable threshold (4.4%), and diaphragmatic stimulation (1.7%). Significant independent predictors of LV lead implant failure included younger age (odds ratio [OR] 1.01; 95% confidence interval [CI] 0.1.01-1.02), female sex (OR 1.38; 95% CI 1.29-1.47), black race (vs white, OR 1.44; 95% CI 1.32-1.57), Hispanic ethnicity (OR 1.23; 95% CI 1.08-1.40), QRS duration (OR 1.055 per 10 ms; 95% CI 1.038-1.072 per 10 ms), obstructive sleep apnea (OR 1.14; 95% CI 1.04-1.24), and implantation by a physician without specialized training (vs electrophysiology trained, OR 1.53; 95% CI 1.34-1.76).

CONCLUSION

LV lead implant failure is uncommon in the current era and is most commonly due to coronary sinus access failure. Predictors of LV lead implant failure included younger age, female sex, black race, Hispanic ethnicity, increased QRS duration, sleep apnea, and absence of electrophysiology training.

Development of the Implantable Cardioverter-Defibrillator: JACC Historical Breakthroughs in Perspective

Implantable cardioverter-defibrillators (ICDs) represent transformational technology, arguably the most significant advance in cardiovascular medicine in 50 years. The vision and determination of pioneers Mirowski and Mower was fundamental to this monumental achievement, working with limited resources and confronted by skepticism/criticism from medical establishment. The inventors were followed >35 years in which a multitude of innovative clinical scientists and engineers introduced technological advances leading to the sophisticated devices in practice today. A pivotal patient experiment with automated termination of ventricular fibrillation (1980) led to U.S. Food and Drug Administration approval. Transvenous lead systems converted ICDs from thoracotomy-based secondary prevention to primary prevention of sudden death devices in countless patients worldwide. ICD acceptance was solidified by prospective randomized controlled trials showing reduced mortality superior to antiarrhythmic drugs. ICDs eventually expanded from coronary disease to inherited arrhythmia conditions (eg, hypertrophic cardiomyopathy). The ICD breakthrough story demonstrates how significant progress is possible in medicine against all odds, given fearless imagination to pursue novel ideas that conflict with accepted wisdom.

Survival Probability and Survival Benefit Associated With Primary Prevention Implantable Cardioverter-Defibrillator Generator Changes

Background As patients derive variable benefit from generator changes (GCs) of implantable cardioverter-defibrillators (ICDs) with an original primary prevention (PP) indication, better predictors of outcomes are needed. Methods and Results In the National Cardiovascular Data Registry ICD Registry, patients undergoing GCs of initial non-cardiac resynchronization therapy PP ICDs in 2012 to 2016, predictors of post-GC survival and survival benefit versus control heart failure patients without ICDs were assessed. These included predicted annual mortality based on the Seattle Heart Failure Model, left ventricular ejection fraction (LVEF) >35%, and the probability that a patient's death would be arrhythmic (proportional risk of arrhythmic death [PRAD]). In 40 933 patients undergoing GCs of initial noncardiac resynchronization therapy PP ICDs (age 67.7±12.0 years, 24.5% women, 34.1% with LVEF >35%), Seattle Heart Failure Model-predicted annual mortality had the greatest effect size for decreased post-GC survival (P<0.0001). Patients undergoing GCs of initial noncardiac resynchronization therapy PP ICDs with LVEF >35% had a lower Seattle Heart Failure Model-adjusted survival versus 23 472 control heart failure patients without ICDs (model interaction hazard ratio, 1.21 [95% CI, 1.11-1.31]). In patients undergoing GCs of initial noncardiac resynchonization therapy PP ICDs with LVEF ≤35%, the model indicated worse survival versus controls in the 21% of patients with a PRAD <43% and improved survival in the 10% with PRAD >65%. The association of the PRAD with survival benefit or harm was similar in patients with or without pre-GC ICD therapies. Conclusions Patients who received replacement of an ICD originally implanted for primary prevention and had at the time of GC either LVEF >35% alone or both LVEF ≤35% and PRAD <43% had worse survival versus controls without ICDs.

Longitudinal Outcomes of Subcutaneous or Transvenous Implantable Cardioverter-Defibrillators in Older Patients

BACKGROUND

The subcutaneous (S-) implantable cardioverter-defibrillator (ICD) is an alternative to the transvenous (TV-) ICD that is increasingly implanted in younger patients; data on the safety and effectiveness of the S-ICD in older patients are lacking.

OBJECTIVES

The purpose of this study was to compare outcomes among older patients who received an S- or TV-ICD.

METHODS

The authors compared S-ICD and single-chamber TV-ICD implants in Fee-For-Service Medicare beneficiaries using the National Cardiovascular Data Registry ICD Registry. Outcomes were ascertained from Medicare claims data. Cox regression or competing-risk models (with TV-ICD as reference) with overlap weights were used to compare death and nonfatal outcomes (device reoperation, device removal for infection, device reoperation without infection, and cardiovascular admission), respectively. Recurrent all-cause readmissions were compared using Anderson-Gill models.

RESULTS

A total of 16,063 patients were studied (age 72.6 ± 5.9 years, 28.4% women, ejection fraction 28.3 ± 8.9%). Compared with TV-ICD patients (n = 15,072), S-ICD patients (n = 991, 6.2% overall) were more often Black, younger, and dialysis dependent and less likely to have history of atrial fibrillation or flutter. In adjusted analyses, there were no differences between device type and risk of all-cause mortality (HR: 1.020; 95% CI: 0.819-1.270), device reoperation (subdistribution [s] HR: 0.976; 95% CI: 0.645-1.479), device removal for infection (sHR: 0.614; 95% CI: 0.138-2.736), device reoperation without infection (sHR: 0.975; 95% CI: 0.632-1.506), cardiovascular readmission (sHR: 1.087; 95% CI: 0.912-1.295), or recurrent all-cause readmission (HR: 1.072; 95% CI: 0.990-1.161).

CONCLUSIONS

In a large representative national cohort of older patients undergoing ICD implantation, risk of death, device reoperation, device removal for infection, device reoperation without infection, and cardiovascular and all-cause readmission were similar among S- and TV-ICD recipients.

Trends in Use of Single- vs Dual-Chamber Implantable Cardioverter-Defibrillators Among Patients Without a Pacing Indication, 2010-2018

IMPORTANCE

Use of dual-chamber implantable cardioverter-defibrillator (ICD) systems among patients without a pacing indication is an example of low-value care given higher procedural risks, higher costs, and little evidence for benefit from an atrial lead. However, variation in the use of dual-chamber systems was present among patients without a pacing indication.

OBJECTIVE

To examine the temporal trends and hospital variation in use of single- and dual-chamber ICD implantation among patients without a pacing indication undergoing first-time ICD implantation.

DESIGN, SETTING, AND PARTICIPANTS

A multicenter cross-sectional study was conducted using the US National Cardiovascular Data Registry ICD Registry. A total of 266 182 patients undergoing initial implantation of a single- or dual-chamber transvenous ICD without a bradycardia pacing indication, class I or II cardiac resynchronization therapy indication, or history of atrial fibrillation or atrial flutter were included. The study was conducted from April 1, 2010, to December 31, 2018; data analysis was performed from October 19, 2020, to January 5, 2022.

EXPOSURES

Implantation of a single- or dual-chamber ICD.

MAIN OUTCOMES AND MEASURES

Temporal trends among patients undergoing single- vs dual-chamber ICDs were determined using the Cochran-Armitage trend test, and hospital-level variation using adjusted hospital median odds ratios was examined.

RESULTS

A total of 266 182 patients (single-chamber ICD, 134 925; dual-chamber ICD, 131 257) were included in this analysis; mean (SD) age was 58.0 (14.0) years and 91 990 patients (68.2%) were men. The use of dual-chamber ICDs decreased from 64.7% (n = 15 694) in 2010 to 42.2% (n = 9762) in 2018 (P < .001). Adjusted for patient characteristics, the median hospital-level proportion of single-chamber ICDs increased from 42.9% (95% CI, 42.6%-45.0%) in 2010 to 50.0% (95% CI, 47.8%-51.0%) in 2018. The median odds ratio for the use of dual-chamber ICDs, adjusted for patient characteristics, was 1.6 (95% CI, 1.6-1.8) in 2010 and 1.5 (95% CI, 1.5-1.8) in 2018, indicating decreasing but persistent variation in use.

CONCLUSIONS AND RELEVANCE

In this national study of US patients undergoing first-time ICD implantation without a clinical indication for an atrial lead, the use of dual-chamber devices decreased. However, institutional variability in the use of atrial leads persists, suggesting differences in individual or institutional cultures of real-world practice and opportunity to reduce this low-value practice.

Informed consent and compulsory medical device registries: ethics and opportunities

Many high-risk medical devices earn US marketing approval based on limited premarket clinical evaluation that leaves important questions unanswered. Rigorous postmarket surveillance includes registries that actively collect and maintain information defined by individual patient exposures to particular devices. Several prominent registries for cardiovascular devices require enrolment as a condition of reimbursement for the implant procedure, without informed consent. In this article, we focus on whether these registries, separate from their legal requirements, have an ethical obligation to obtain informed consent from enrolees, what is lost in not doing so, and the ways in which seeking and obtaining consent might strengthen postmarket surveillance in the USA.

Defibrillation Safety Margin Testing in Patients With Congenital Heart Disease: Results From the NCDR

OBJECTIVES

This study analyzed the predictors of defibrillation safety margin (DSM) testing at the time of implantable cardioverter-defibrillator (ICD) insertion and factors associated with inadequate DSM in patients with congenital heart disease (CHD).

BACKGROUND

There are few data about the prevalence and safety of DSM testing in those with CHD.

METHODS

A retrospective analysis was performed of all patients with atrial or ventricular septal defect, tetralogy of Fallot, transposition of the great vessels, Ebstein anomaly, or common ventricle undergoing a transvenous ICD procedure in the National Cardiovascular Data Registry (NCDR) ICD Registry from April 2010 to March 2016, and DSM testing was assessed. Inadequate DSM was defined as a lowest successful energy tested <10 J than the maximum output of the ICD generator.

RESULTS

Of all ICD recipients (N = 7,024), DSM testing was performed in 52.0% (n = 3,654). The mean lowest successful energy tested was 20.7 ± 7.3 J. Of those with DSM adequacy data available (n = 3,623), an inadequate DSM occurred in 13.8% (n = 501). After multivariable adjustment, DSM testing was not associated with in-hospital complications or death (odds ratio [OR]: 1.00; 95% confidence interval [CI]: 0.79 to 1.28) but was associated with lower odds of prolonged hospital stay (>3 days) (OR: 0.71; 95% CI: 0.60 to 0.84; p < 0.0001). An inadequate DSM was not associated with in-hospital death or complications (OR: 1.27; 95% CI: 0.79 to 2.04) or prolonged hospital stay (OR: 1.34; 95% CI: 0.995 to 1.81).

CONCLUSIONS

DSM testing is being performed less frequently over time and seems safe in those with CHD. An inadequate DSM was not associated with worse in-hospital outcomes.

Use and Outcomes of Dual Chamber or Cardiac Resynchronization Therapy Defibrillators Among Older Patients Requiring Ventricular Pacing in the National Cardiovascular Data Registry Implantable Cardioverter Defibrillator Registry

IMPORTANCE

Frequent right ventricular (RV) pacing can cause and exacerbate heart failure. Cardiac resynchronization therapy (CRT) has been shown to be associated with improved outcomes among patients with reduced left ventricular ejection fraction who need frequent RV pacing, but the patterns of use of CRT vs dual chamber (DC) devices and the associated outcomes among these patients in clinical practice is not known.

OBJECTIVE

To assess outcomes, variability in use of device type, and trends in use of device type over time among patients undergoing implantable cardioverter defibrillator (ICD) implantation who were likely to require frequent RV pacing but who did not have a class I indication for CRT.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study used the National Cardiovascular Data Registry (NCDR) ICD Registry. A total of 3100 Medicare beneficiaries undergoing first-time implantation of CRT defibrillator (CRT-D) or DC-ICD from 2010 to 2016 who had a class I or II guideline ventricular bradycardia pacing indication but not a class I indication for CRT were included. Data were analyzed from August 2018 to October 2019.

EXPOSURES

Implantation of a CRT-D or DC-ICD.

MAIN OUTCOMES AND MEASURES

All-cause mortality, heart failure hospitalization, and complications were ascertained from Medicare claims data. Multivariable Cox proportional hazards models and Fine-Gray models were used to evaluate 1-year mortality and heart failure hospitalization, respectively. Multivariable logistic regression was used to evaluate 30-day and 90-day complications. All models accounted for clustering. The median odds ratio (MOR) was used to assess variability and represents the odds that a randomly selected patient receiving CRT-D at a hospital with high implant rates would receive CRT-D if they had been treated at a hospital with low CRT-D implant rates.

RESULTS

A total of 3100 individuals were included. The mean (SD) age was 76.3 (6.4) years, and 2500 (80.6%) were men. The 1698 patients (54.7%) receiving CRT-D were more likely than those receiving DC-ICD to have third-degree atrioventricular block (828 [48.8%] vs 432 [30.8%]; P < .001), nonischemic cardiomyopathy (508 [29.9%] vs 255 [18.2%]; P < .001), and prior heart failure hospitalizations (703 [41.4%] vs 421 [30.0%]; P < .001). Following adjustment, CRT-D was associated with lower 1-year mortality (hazard ratio [HR], 0.70; 95% CI, 0.57-0.87; P = .001) and heart failure hospitalization (subdistribution HR, 0.77; 95% CI, 0.61-0.97; P = .02) and no difference in complications compared with DC-ICD. Hospital variation in use of CRT was present (MOR, 2.00), and the use of CRT in this cohort was higher over time (654 of 1351 [48.4%] in 2010 vs 362 of 594 [60.9%] in 2016; P < .001).

CONCLUSIONS AND RELEVANCE

In this cohort study of older patients in contemporary practice undergoing ICD implantation with a bradycardia pacing indication but without a class I indication for CRT, CRT-D was associated with better outcomes compared with DC devices. Variability in use of device type was observed, and the rate of CRT implantation increased over time.

Comparison of cost-effectiveness of implantable cardioverter defibrillator therapy in patients for primary prevention in Latin America: an analysis using the Improve SCA study

OBJECTIVE

The mortality benefit of implantable cardioverter defibrillators (ICDs) for primary prevention (PP) of sudden cardiac arrest (SCA) has been well-established, but ICD therapy remains globally underutilized. The results of the Improve SCA study showed a 49% relative risk reduction in all-cause mortality among ICD patients with 1.5 primary prevention (1.5PP) characteristics (patients with one or more risk factors, p < 0.0001). We evaluated the cost-effectiveness of ICD compared to no ICD therapy among patients with 1.5PP characteristics in three Latin American countries and analyzed the factors involved in cost-effectiveness.

METHODS

We used a published Markov model that compares costs and outcomes of ICD to no ICD therapy from local payers' perspective and included country-specific and disease-specific inputs from the Improve SCA study and current literature. We used WHO-recommended willingness-to-pay (WTP) thresholds to assess cost-effectiveness and compared model outcomes between countries.

RESULTS

Incremental costs per QALY (quality-adjusted life year) saved by ICD compared to no ICD therapy are Colombian Pesos COP$46,729,026 in Colombia, Mexican Pesos MXN$246,016 in Mexico, and Uruguayan Pesos UYU$1,213,614 in Uruguay in the base case scenario; all three figures are between 1-3-times GDP per capita for each country. One-way and probabilistic sensitivity analyses confirm the base case scenario results. Non-cardiac accumulated deaths are lower in Mexico, resulting in a comparatively increased cost-effective ICD therapy.

LIMITATIONS

The Improve SCA study was not randomized, so clinical results could be biased; however, measures were taken to reduce this bias. Costs and benefits were modelled beyond the timeline of direct observation in the Improve SCA study.

CONCLUSIONS

ICD therapy is cost-effective in Mexico and Uruguay and potentially cost-effective in Colombia for a 1.5PP population. Variability in ICER estimates by country can be explained by differences in non-cardiac deaths and cost inputs.

Implantable cardioverter defibrillator therapy is cost effective for primary prevention patients in Taiwan: An analysis from the Improve SCA trial

Objective

Implantable cardiac defibrillators (ICDs) for primary prevention (PP) of sudden cardiac arrest (SCA) are well-established but underutilized globally. The Improve SCA study has identified a cohort of patients called 1.5 primary prevention (1.5PP) based on PP patients with the presence of certain risk factors. We evaluated the cost-effectiveness of ICD therapy compared to no ICD among the PP population and the subset of 1.5PP patients in Taiwan.

Methods

A Markov model was run over a lifetime time horizon from the Taiwan payer perspective. Mortality and utility estimates were obtained from the literature (PP) and the IMPROVE SCA trial (1.5PP). Cost inputs were obtained from the Taiwan National Health Insurance Administration (NHIA), Ministry of Health and Welfare. We used a willingness-to-pay (WTP) threshold of NT$2,100,000, as established through standard WTP research methods and in alignment with World Health Organization recommendations.

Results

The total discounted costs for ICD therapy and no ICD therapy were NT$1,664,259 and NT$646,396 respectively for PP, while they were NT$2,410,603 and NT$905,881 respectively for 1.5PP. Total discounted QALYs for ICD therapy and no ICD therapy were 6.48 and 4.98 respectively for PP, while they were 10.78 and 7.71 respectively for 1.5PP. The incremental cost effectiveness ratio was NT$708,711 for PP and NT$441,153 for 1.5PP, therefore ICD therapy should be considered cost effective for PP and highly cost effective for 1.5PP.

Conclusions

ICD therapy compared to no ICD therapy is cost-effective in the whole PP population and highly cost-effective in the subset 1.5PP population in Taiwan.

Trends in Use and In-Hospital Outcomes of Subcutaneous Implantable Cardioverter Defibrillators in Patients Undergoing Long-Term Dialysis

BACKGROUND AND OBJECTIVES

Patients on dialysis are at high risk of complications related to implantable cardioverter defibrillator (ICD) implantation; use of subcutaneous ICDs may be preferred over transvenous devices due to lower risk of bloodstream infection and interference with vascular access sites. We evaluated trends in use and in-hospital outcomes of subcutaneous compared with transvenous ICDs among patients on dialysis in the United States.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Retrospective analysis of ICD implants from 2012 to 2018 among patients on dialysis reported to the National Cardiovascular Data Registry ICD Registry, a nationally representative US ICD Registry. We examined overall trends in subcutaneous ICD adoption as a proportion of all eligible ICD implants among patients on dialysis and then compared in-hospital outcomes between eligible subcutaneous ICD and transvenous ICD recipients using inverse probability of treatment weighting.

RESULTS

Of the 23,136 total ICD implants in patients on dialysis during the study period, 3195 (14%) were subcutaneous ICDs. Among eligible first-time ICD recipients on dialysis, the proportion of subcutaneous ICDs used increased yearly from 10% in 2012 to 69% in 2018. In propensity score-weighted analysis of 3327 patients, compared with transvenous ICDs, patients on dialysis receiving subcutaneous ICDs had a higher rate of in-hospital cardiac arrest (2% versus 0.4%, P=0.002), but there was no significant difference in total in-hospital complications (2% versus 1%, P=0.08), all-cause death, or length of hospital stay.

CONCLUSIONS

The utilization of subcutaneous ICDs among US patients on dialysis has been steadily increasing. The overall risk of short-term complications is low and comparable with transvenous ICDs, but higher risks of in-hospital cardiac arrest merits closer monitoring and further investigation.

PODCAST

This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2020_09_23_CJN07920520.mp3.

Trends and In-Hospital Outcomes Associated With Adoption of the Subcutaneous Implantable Cardioverter Defibrillator in the United States

Importance

Trends and in-hospital outcomes associated with early adoption of the subcutaneous implantable cardioverter defibrillator (S-ICD) in the United States have not been described.

Objectives

To describe early use of the S-ICD in the United States and to compare in-hospital outcomes among patients undergoing S-ICD vs transvenous (TV)-ICD implantation.

Design, Setting, and Participants

A retrospective analysis of 393 734 ICD implants reported to the National Cardiovascular Data Registry ICD Registry, a nationally representative US ICD registry, between September 28, 2012 (US Food and Drug Administration S-ICD approval date), and March 31, 2015, was conducted. A 1:1:1 propensity-matched analysis of 5760 patients was performed to compare in-hospital outcomes among patients with S-ICD with those of patients with single-chamber (SC)-ICD and dual-chamber (DC)-ICD.

Main Outcomes and Measures

Analysis of trends in S-ICD adoption as a function of total ICD implants and comparison of in-hospital outcomes (death, complications, and defibrillation threshold [DFT] testing) among S-ICD and TV-ICD recipients.

Results

Of the 393 734 ICD implants evaluated during the study period, 3717 were S-ICDs (0.9%). A total of 109 445 (27.8%) of the patients were female; the mean (SD) age was 67.03 (13.10) years. Use of ICDs increased from 0.2% during the fourth quarter of 2012 to 1.9% during the first quarter of 2015. Compared with SC-ICD and DC-ICD recipients, those with S-ICDs were more often younger, female, black, undergoing dialysis, and had experienced prior cardiac arrest. Among 2791 patients with S-ICD who underwent DFT testing, 2588 (92.7%), 2629 (94.2%), 2635 (94.4%), and 2784 (99.7%) were successfully defibrillated (≤65, ≤70, ≤75, and ≤80 J, respectively). In the propensity-matched analysis of 5760 patients, in-hospital complication rates associated with S-ICDs (0.9%) were comparable to those of SC-ICDs (0.6%) (P = .27) and DC-ICD rates (1.5%) (P = .11). Mean (SD) length of stay after S-ICD implantation was comparable to that after SC-ICD implantation (1.1 [1.5] vs 1.0 [1.2] days; P = .77) and less than after DC-ICD implantation (1.1 [1.5] vs 1.2 [1.5] days; P < .001).

Conclusions and Relevance

The use of S-ICDs is rapidly increasing in the United States. Early adoption has been associated with low complication rates and high rates of successful DFT testing despite frequent use in patients with a high number of comorbidities.

Appropriate Classification and Filtering of Electromagnetic Interference by the S-ICD Sensing Algorithm During Surgery

The subcutaneous implantable cardioverter defibrillator (S-ICD) is a new device used for the prevention of sudden cardiac death. Best practices in the perioperative management of the S-ICD are not established; therefore, clinicians typically deactivate the device during surgery, with reinterrogation and activation postoperatively. This could put the patient at risk for being discharged with the device "off." We present two cases where electromagnetic interference was appropriately detected by the S-ICD and filtered. These cases present an important clinical finding that could lead to less deactivation of devices during surgery. Further research will be required to define which surgical procedures require magnet, reprogramming, or no changes.

Simultaneous lead traction from above and below: A novel technique to reduce the risk of superior vena cava injury during transvenous lead extraction

BACKGROUND

Superior vena cava (SVC) injury is a rare but dreaded complication during percutaneous transvenous lead extraction (TLE) that carries high morbidity and mortality. Despite technological advances and improved efficacy, complication rates remain unchanged.

OBJECTIVE

We sought to develop and test a novel technique that could reduce the risk of SVC injury during TLE.

METHODS

Fifteen patients referred for TLE of an implantable cardioverter-defibrillator lead were included. Patients underwent fluoroscopic and intracardiac echocardiographic (ICE) imaging of the lead-SVC interface with traction from above, below, and simultaneously. Clinical characteristics, fluoroscopic and ICE findings, and procedural outcomes were collected and analyzed.

RESULTS

Fourteen of 15 patients were men (93%) with a mean age of 58 years. The mean lead dwell time was 8.09 ± 3.97 years (range 1.08-16.25 years), and 12 of 15 leads (80%) were dual-coil. Acceptable ICE imaging was not possible in 3 of 15 patients (20%). Simultaneous traction showed greater leftward fluoroscopic shift compared with traction from above (24.96 ± 8.82 mm vs 13.68 ± 6.86 mm; P < .01), created greater separation between the lead and the SVC wall upon ICE imaging (2.0 ± 0.52 mm vs 1.24 ± 0.38 mm; P < .01), and maintained a more parallel relationship of the lead with the SVC wall (24.41° ± 4.14° vs 27.91° ± 4.92°; P < .05).

CONCLUSION

In patients presenting for TLE, simultaneous traction results in increased separation and a more parallel alignment of the lead and SVC wall, allowing the sheath to be better oriented in the desired cleavage plane. This improved sheath alignment is particularly critical when powered sheaths are to be used.

Device Therapies Among Patients Receiving Primary Prevention Implantable Cardioverter-Defibrillators in the Cardiovascular Research Network

BACKGROUND

Primary prevention implantable cardioverter-defibrillators (ICDs) reduce mortality in selected patients with left ventricular systolic dysfunction by delivering therapies (antitachycardia pacing or shocks) to terminate potentially lethal arrhythmias; inappropriate therapies also occur. We assessed device therapies among adults receiving primary prevention ICDs in 7 healthcare systems.

METHODS AND RESULTS

We linked medical record data, adjudicated device therapies, and the National Cardiovascular Data Registry ICD Registry. Survival analysis evaluated therapy probability and predictors after ICD implant from 2006 to 2009, with attention to Centers for Medicare and Medicaid Services Coverage With Evidence Development subgroups: left ventricular ejection fraction, 31% to 35%; nonischemic cardiomyopathy <9 months' duration; and New York Heart Association class IV heart failure with cardiac resynchronization therapy defibrillator. Among 2540 patients, 35% were <65 years old, 26% were women, and 59% were white. During 27 (median) months, 738 (29%) received ≥1 therapy. Three-year therapy risk was 36% (appropriate, 24%; inappropriate, 12%). Appropriate therapy was more common in men (adjusted hazard ratio [HR], 1.84; 95% confidence interval [CI], 1.43-2.35). Inappropriate therapy was more common in patients with atrial fibrillation (adjusted HR, 2.20; 95% CI, 1.68-2.87), but less common among patients ≥65 years old versus younger (adjusted HR, 0.72; 95% CI, 0.54-0.95) and in recent implants (eg, in 2009 versus 2006; adjusted HR, 0.66; 95% CI, 0.46-0.95). In Centers for Medicare and Medicaid Services Coverage With Evidence Development analysis, inappropriate therapy was less common with cardiac resynchronization therapy defibrillator versus single chamber (adjusted HR, 0.55; 95% CI, 0.36-0.84); therapy risk did not otherwise differ for Centers for Medicare and Medicaid Services Coverage With Evidence Development subgroups.

CONCLUSIONS

In this community cohort of primary prevention patients receiving ICD, therapy delivery varied across demographic and clinical characteristics, but did not differ meaningfully for Centers for Medicare and Medicaid Services Coverage With Evidence Development subgroups.

Prophylactic implantable cardioverter defibrillator in heart failure: the growing evidence for all or Primum non nocere for some?

Heart failure (HF) is a common health problem and has reached epidemic in many western countries. Despite the current era of HF treatment, the risk of sudden cardiac death (SCD) in HF remains significant. Implantable cardioverter defibrillator (ICD) support has been shown to reduce the risk of SCD in patients with HF and impaired left ventricular function. Prophylactic ICD implantation in HF patients seems a logical step to reduce mortality through a reduction in SCD. However, ICD implantation is an invasive procedure, and both short- and long-term complications can occur. This needs to be carefully considered when evaluating the risk-benefit ratio of ICD implantation for individual patients. As the severity of HF increases, the proportion of SCD compared with HF-related deaths decreases. The challenge lies in identifying patients with HF who are at significant risk of SCD and who would most benefit from an ICD in addition to other anti-arrhythmic strategies. This review offers insight on the applicability and practicability of ICD for this growing population.

Impact of Abandoned Leads on Cardiovascular Implantable Electronic Device Infections: A Propensity Matched Analysis of MEDIC (Multicenter Electrophysiologic Device Infection Cohort)

OBJECTIVES

This study sought to evaluate the impact of abandoned cardiovascular implantable electronic device (CIED) leads on the presentation and management of device-related infections.

BACKGROUND

Device infection is a serious consequence of CIEDs and necessitates removal of all hardware for attempted cure. The merits of extracting or retaining presumed sterile but nonfunctioning leads is a subject of ongoing debate.

METHODS

The MEDIC (Multicenter Electrophysiologic Device Infection Cohort) prospectively enrolled patients with CIED infections at 10 institutions in the United States and abroad between January 1, 2009, and December 31, 2012. Within a propensity-matched cohort, relevant clinical information was compared between patients who had 1 or more abandoned leads at the time of infection and those who had none.

RESULTS

Matching produced a cohort of 264 patients, including 176 with no abandoned leads and 88 with abandoned leads. The groups were balanced with respect to Charlson comorbidity index, oldest lead age, device type, sex, and race. At the time of admission, those with abandoned leads were less likely to demonstrate systemic signs of infection, including leukocytosis (p = 0.023) and positive blood cultures (p = 0.005). Conversely, patients with abandoned leads were more likely to demonstrate local signs of infections, including skin erosion (p = 0.031) and positive pocket cultures (p = 0.015). In addition, patients with abandoned leads were more likely to require laser extraction (p = 0.010).

CONCLUSIONS

The results of a large prospective registry of CIED infections demonstrated that patients with abandoned leads may present with different signs, symptoms, and microbiological findings and require laser extraction more than those without abandoned leads.

Complications Associated With Implantable Cardioverter Defibrillators in Adults With Congenital Heart Disease or Left Ventricular Noncompaction Cardiomyopathy (From the NCDR® Implantable Cardioverter-Defibrillator Registry)

Patients with childhood heart disease are living longer and entering adulthood, and may undergo implantable cardioverter-defibrillator (ICD) implantation to reduce the risk of sudden death. We evaluated the characteristics of adult patients with congenital heart disease or left ventricular noncompaction cardiomyopathy (LVNC) in the National Cardiovascular Disease Registry ICD Registry and determined ICD-related in-hospital complications. Patients with LVNC or transposition of the great arteries, tetralogy of Fallot, Ebstein's anomaly, atrial septal defect, ventricular septal defect, or common ventricle were identified in the registry. In-hospital complications were compared among different diagnoses using the chi-square test for categorical variables and the F-test in analyses of variance for continuous variables. A total of 3,077 patients were identified. The mean age was 48.0 ± 16.0 years, and 39.9% were female. Single-chamber ICDs were implanted in 25.2%, dual chamber in 41.9%, and cardiac resynchronization in 30.8%. Intraprocedural or postprocedural complications occurred in 70 patients (2.3%); there were 6 in-hospital deaths (0.2%). The most frequent complications were acute lead dislodgments, pneumothorax, and hematomas. Patients with Ebstein's anomaly had the greatest complication rate (8.3%, p = 0.03). The complication rate was 1.55% in single-chamber devices, 1.86% in dual chamber, and 3.5% in cardiac resynchronization (p < 0.001). For initial implants, the complication rate was 2.55%, 1.62% in generator replacements, and 8.77% in lead revisions (p = 0.001). In conclusion, in this large contemporary adult cohort of congenital heart disease and LVNC patients who underwent ICD implant procedures, periprocedural complication rates were low. Lead-related risks predominated.

Outcomes Associated With Extraction Versus Capping and Abandoning Pacing and Defibrillator Leads

Background:

Lead management is an increasingly important aspect of care in patients with cardiac implantable electronic devices; however, relatively little is known about long-term outcomes after capping and abandoning leads.

Methods:

Using the 5% Medicare sample, we identified patients with de novo cardiac implantable electronic device implantations between January 1, 2000, and December 31, 2013, and with a subsequent lead addition or extraction ≥12 months after the de novo implantation. Patients who underwent extraction for infection were excluded. Using multivariable Cox proportional hazards models, we compared cumulative incidence of all-cause mortality, device-related infection, device revision, and lead extraction at 1 and 5 years for the extraction versus the cap and abandon group.

Results:

Among 6859 patients, 1113 (16.2%) underwent extraction, whereas 5746 (83.8%) underwent capping and abandonment. Extraction patients tended to be younger (median, 78 versus 79 years; P <0.0001), were less likely to be male (65% versus 68%; P =0.05), and had shorter lead dwell time (median, 3.0 versus 4.0 years; P <0.0001) and fewer comorbidities. Over a median follow-up of 2.4 years (25th, 75th percentiles, 1.0, 4.3 years), the overall 1-year and 5-year cumulative incidence of mortality was 13.5% (95% confidence interval [CI], 12.7–14.4) and 54.3% (95% CI, 52.8–55.8), respectively. Extraction was associated with a lower risk of device infection at 5 years relative to capping (adjusted hazard ratio, 0.78; 95% CI, 0.62–0.97; P =0.027). There was no association between extraction and mortality, lead revision, or lead extraction at 5 years.

Conclusions:

Elective lead extraction for noninfectious indications had similar long-term survival to that for capping and abandoning leads in a Medicare population. However, extraction was associated with lower risk of device infections at 5 years.

Can machine learning complement traditional medical device surveillance? A case study of dual-chamber implantable cardioverter-defibrillators

BACKGROUND

Machine learning methods may complement traditional analytic methods for medical device surveillance.

METHODS AND RESULTS

Using data from the National Cardiovascular Data Registry for implantable cardioverter-defibrillators (ICDs) linked to Medicare administrative claims for longitudinal follow-up, we applied three statistical approaches to safety-signal detection for commonly used dual-chamber ICDs that used two propensity score (PS) models: one specified by subject-matter experts (PS-SME), and the other one by machine learning-based selection (PS-ML). The first approach used PS-SME and cumulative incidence (time-to-event), the second approach used PS-SME and cumulative risk (Data Extraction and Longitudinal Trend Analysis [DELTA]), and the third approach used PS-ML and cumulative risk (embedded feature selection). Safety-signal surveillance was conducted for eleven dual-chamber ICD models implanted at least 2,000 times over 3 years. Between 2006 and 2010, there were 71,948 Medicare fee-for-service beneficiaries who received dual-chamber ICDs. Cumulative device-specific unadjusted 3-year event rates varied for three surveyed safety signals: death from any cause, 12.8%-20.9%; nonfatal ICD-related adverse events, 19.3%-26.3%; and death from any cause or nonfatal ICD-related adverse event, 27.1%-37.6%. Agreement among safety signals detected/not detected between the time-to-event and DELTA approaches was 90.9% (360 of 396, k=0.068), between the time-to-event and embedded feature-selection approaches was 91.7% (363 of 396, k=-0.028), and between the DELTA and embedded feature selection approaches was 88.1% (349 of 396, k=-0.042).

CONCLUSION

Three statistical approaches, including one machine learning method, identified important safety signals, but without exact agreement. Ensemble methods may be needed to detect all safety signals for further evaluation during medical device surveillance.

Outcomes Among Older Patients Receiving Implantable Cardioverter-Defibrillators for Secondary Prevention: From the NCDR ICD Registry

BACKGROUND

Clinical trials of implantable cardioverter-defibrillators (ICDs) for secondary prevention of sudden cardiac death were conducted nearly 2 decades ago and enrolled few older patients.

OBJECTIVES

This study assessed morbidity and mortality of older patients receiving ICDs for secondary prevention in contemporary clinical practice.

METHODS

We identified 12,420 Medicare beneficiaries from the National Cardiovascular Data Registry ICD Registry undergoing first-time secondary prevention ICD implantation between 2006 and 2009 in 956 U.S. hospitals. Risks of death, hospitalization, and admission to a skilled nursing facility (SNF) were assessed over 2 years in age strata (65 to 69, 70 to 74, 75 to 79, and ≥80 years of age) using Medicare claims. The adjusted association between age and outcomes was evaluated using multivariable models.

RESULTS

The mean age was 75 years at the time of implantation; 25.3% were <70 years of age and 25.7% were ≥80 years of age. Overall, the risk of death at 2 years was 21.8%, ranging from 14.7% among those <70 years of age to 28.9% among those ≥80 years of age (adjusted risk ratio [aRR]: 2.01; 95% confidence interval [CI]: 1.85 to 2.33; p for trend <0.001). The cumulative incidence of hospitalizations was 65.4%, ranging from 60.5% in those <70 years of age to 71.5% in those ≥80 years of age (aRR: 1.27; 95% CI: 1.19 to 1.36; p for trend <0.001). The cumulative incidence of admission to a SNF ranged from 13.1% among those <70 years of age to 31.9% among those ≥80 years of age (aRR: 2.67; 95% CI: 2.37 to 3.01; p for trend <0.001); SNF admission risk was highest in the first 30 days.

CONCLUSIONS

Almost 4 in 5 older patients receiving a secondary prevention ICD survives at least 2 years. High hospitalization and SNF admission rates, particularly among the oldest patients, identify substantial care needs after device implantation.

Comparative Effectiveness of Cardiac Resynchronization Therapy Among Patients With Heart Failure and Atrial Fibrillation: Findings From the National Cardiovascular Data Registry's Implantable Cardioverter-Defibrillator Registry

BACKGROUND

Atrial fibrillation is common in patients with heart failure, but outcomes of patients with both conditions who receive cardiac resynchronization therapy with defibrillator (CRT-D) compared with an implantable cardioverter-defibrillator (ICD) alone are unclear.

METHODS AND RESULTS

Using the National Cardiovascular Data Registry's ICD Registry linked with Medicare claims, we identified 8951 patients with atrial fibrillation who were eligible for CRT-D and underwent first-time device implantation for primary prevention between April 2006 and December 2009. We used Cox proportional hazards models and inverse probability-weighted estimates to compare outcomes with CRT-D versus ICD alone. Cumulative incidence of mortality (744 [33%] for ICD; 1893 [32%] for CRT-D) and readmission (1788 [76%] for ICD; 4611 [76%] for CRT-D) within 3 years and complications within 90 days were similar between groups. After inverse weighting for the probability of receiving CRT-D, risks of mortality (hazard ratio, 0.83; 95% confidence interval, 0.75-0.92), all-cause readmission (hazard ratio, 0.86; 95% confidence interval, 0.80-0.92), and heart failure readmission (hazard ratio, 0.68; 95% confidence interval, 0.62-0.76) were lower with CRT-D compared with ICD alone. There was no significant difference in the 90-day complication rate (hazard ratio, 0.88; 95% confidence interval, 0.60-1.29). We observed hospital-level variation in the use of CRT-D among patients with atrial fibrillation.

CONCLUSIONS

Among eligible patients with heart failure and atrial fibrillation, CRT-D was associated with lower risks of mortality, all-cause readmission, and heart failure readmission, as well as with a similar risk of complications compared with ICD alone.

Nursing Home Use After Implantable Cardioverter-Defibrillator Implantation in Older Adults: Results from the National Cardiovascular Data Registry

OBJECTIVES

To evaluate the incidence and characteristics of nursing home (NH) use after implantable cardioverter-defibrillator (ICD) implantation.

DESIGN

Cohort study.

SETTING

Medicare beneficiaries in the National Cardiovascular Data Registry-ICD Registry.

PARTICIPANTS

Individuals aged 65 and older receiving ICDs between January 1, 2006, and March 31, 2010 (N = 192,483).

MEASUREMENTS

Proportion of ICD recipients discharged to NHs directly after device placement, cumulative incidence of long-term NH admission, and factors associated with immediate discharge to a NH and time to long-term NH admission.

RESULTS

Over 4 years, 40.6% of the cohort died, and 35,939 (18.7%) experienced at least one NH admission, including 4.0% directly discharged to a NH after ICD implantation and 2.8% admitted to long-term NH care during follow-up. The cumulative incidence of long-term NH admission, accounting for the competing risk of death, was 1.7% at 1 year, 3.8% at 3 years, and 4.6% at 4 years; 20.1% of individuals admitted to a NH died there. Factors most strongly associated with direct NH discharge and time to long-term NH care were older age (adjusted odds ratio (AOR) = 2.09, 95% confidence interval (CI) = 2.01-2.17 per 10-year increment; adjusted hazard ratio (AHR) = 1.88, 95% CI = 1.80-1.97, respectively), dementia (AOR = 2.60, 95% CI = 2.25-3.01; AHR = 2.50, 95% CI = 2.14-2.93, respectively), and Medicare Part A claim for NH stay in prior 6 months (AOR = 3.96, 95% CI = 3.70-4.25; AHR = 2.88, 95% CI = 2.65-3.14, respectively).

CONCLUSION

Nearly one in five individuals are admitted to NHs over a median of 1.6 years of follow-up after ICD implantation. Understanding these outcomes may help inform the clinical care of these individuals.

Transaxillary Subpectoral Placement of Cardiac Implantable Electronic Devices in Young Female Patients

Background

The current indications of cardiac implantable electronic devices (CIEDs) have expanded to include young patients with serious cardiac risk factors, but CIED placement has the disadvantage of involving unsightly scarring and bulging of the chest wall. A collaborative team of cardiologists and plastic surgeons developed a technique for the subpectoral placement of CIEDs in young female patients via a transaxillary approach.

Methods

From July 2012 to December 2015, subpectoral CIED placement via an axillary incision was performed in 10 young female patients, with a mean age of 25.9 years and mean body mass index of 20.1 kg/m2. In the supine position, with the patient's shoulder abducted, an approximately 5-cm linear incision was made along one of the deepest axillary creases. The submuscular plane was identified at the lateral border of the pectoralis major, and the dissection continued over the clavipectoral fascia until the subpectoral pocket could securely receive a pulse generator. Slight upward dissection also exposed an entrance to the subclavian vein, allowing the cardiology team to gain access to the vein. One patient with dilated cardiomyopathy underwent augmentation mammoplasty and CIED insertion simultaneously.

Results

One case of late-onset device infection occurred. All patients were highly satisfied with the results and reported that they would recommend the procedure to others.

Conclusions

With superior aesthetic outcomes compared to conventional methods, the subpectoral placement of CIEDs via a transaxillary approach is an effective, single-incision method to hide operative scarring and minimize bulging of the device, and is particularly beneficial for young female or lean patients.

Association Between a Prolonged PR Interval and Outcomes of Cardiac Resynchronization Therapy: A Report From the National Cardiovascular Data Registry

BACKGROUND

A prolonged PR interval is common among cardiac resynchronization therapy (CRT) candidates; however, the association between PR interval and outcomes is unclear, and the data are conflicting.

METHODS

We conducted inverse probability weighted analyses of 26 451 CRT-eligible (ejection fraction ≤35, QRS ≥120 ms) patients from the National Cardiovascular Data Registry ICD Registry to assess the association between a prolonged PR interval (≥230 ms), receipt of CRT with defibrillator (CRT-D) versus implantable cardioverter defibrillator (ICD), and outcomes. We first tested the association between a prolonged PR interval and outcomes among patients stratified by device type. Next, we performed a comparative effectiveness analysis of CRT-D versus ICD among patients when stratified by PR interval. Using Medicare claims data, we followed up with patients up to 5 years for incident heart failure hospitalization or death.

RESULTS

Patients with a PR≥230 ms (15%; n=4035) were older and had more comorbidities, including coronary artery disease, atrial arrhythmias, diabetes mellitus, and chronic kidney disease. After risk adjustment, a PR≥230 ms (versus PR<230 ms) was associated with increased risk of heart failure hospitalization or death among CRT-D (hazard ratio, 1.23; 95% confidence interval, 1.14-1.31; P<0.001) but not ICD recipients (hazard ratio, 1.08; 95% confidence interval, 0.97-1.20; P=0.17) (P_interaction=0.043). CRT-D (versus ICD) was associated with lower rates of heart failure hospitalization or death among patients with PR<230 ms (hazard ratio, 0.79; 95% confidence interval, 0.73-0.85; P<0.001) but not PR≥230 ms (hazard ratio, 1.01; 95% confidence interval, 0.87-1.17; P=0.90) (P_interaction=0.0025).

CONCLUSIONS

A PR≥230 ms is associated with increased rates of heart failure hospitalization or death among CRT-D patients. The real-world comparative effectiveness of CRT-D (versus ICD) is significantly less among patients with a PR≥230 ms in comparison with patients with a PR<230 ms.

Hospice Use Following Implantable Cardioverter-Defibrillator Implantation in Older Patients: Results From the National Cardiovascular Data Registry

BACKGROUND

Older recipients of implantable cardioverter-defibrillators (ICDs) are at increased risk for short-term mortality in comparison with younger patients. Although hospice use is common among decedents aged >65, its use among older ICD recipients is unknown.

METHODS AND RESULTS

Medicare patients aged >65 matched to data in the National Cardiovascular Data Registry - ICD Registry from January 1, 2006 to March 31, 2010 were eligible for analysis (N=194 969). The proportion of ICD recipients enrolled in hospice, cumulative incidence of hospice admission, and factors associated with time to hospice enrollment were evaluated. Five years after device implantation, 50.9% of patients were either deceased or in hospice. Among decedents, 36.8% received hospice services. The cumulative incidence of hospice enrollment, accounting for the competing risk of death, was 4.7% (95% confidence interval [CI], 4.6%-4.8%) within 1 year and 21.3% (95% CI, 20.7%-21.8%) at 5 years. Factors most strongly associated with shorter time to hospice enrollment were older age (adjusted hazard ratio, 1.77; 95% CI, 1.73-1.81), class IV heart failure (versus class I; adjusted hazard ratio, 1.79; 95% CI, 1.66-1.94); ejection fraction <20 (adjusted hazard ratio, 1.57; 95% CI, 1.48-1.67), and greater hospice use among decedents in the patients' health referral region.

CONCLUSIONS

More than one-third of older patients dying with ICDs receive hospice care. Five years after implantation, half of older ICD recipients are either dead or in hospice. Hospice providers should be prepared for ICD patients, whose clinical trajectories and broader palliative care needs require greater focus.

Comparative Effectiveness of CRT-D Versus Defibrillator Alone in HF Patients With Moderate-to-Severe Chronic Kidney Disease

BACKGROUND

Patients with moderate-to-severe chronic kidney disease (CKD) are poorly represented in clinical trials of cardiac resynchronization therapy (CRT).

OBJECTIVES

This study sought to assess the real-world comparative effectiveness of CRT with defibrillator (CRT-D) versus implantable cardioverter-defibrillator (ICD) alone in CRT-eligible patients with moderate-to-severe CKD.

METHODS

We conducted an inverse probability-weighted analysis of 10,946 CRT-eligible patients (ejection fraction <35%, QRS >120 ms, New York Heart Association functional class III/IV) with stage 3 to 5 CKD in the National Cardiovascular Data Registry (NCDR) ICD Registry, comparing outcomes between patients who received CRT-D (n = 9,525) versus ICD only (n = 1,421). Outcomes were obtained via Medicare claims and censored at 3 years. The primary endpoint of heart failure (HF) hospitalization or death and the secondary endpoint of death were assessed with Cox proportional hazards models. HF hospitalization, device explant, and progression to end-stage renal disease were assessed using Fine-Gray models.

RESULTS

After risk adjustment, CRT-D use was associated with a reduction in HF hospitalization or death (hazard ratio [HR]: 0.84; 95% confidence interval [CI]: 0.78 to 0.91; p < 0.0001), death (HR: 0.85; 95% CI: 0.77 to 0.93; p < 0.0004), and HF hospitalization alone (subdistribution HR: 0.84; 95% CI: 0.76 to 0.93; p < 0.009). Subgroup analyses suggested that CRT was associated with a reduced risk of HF hospitalization and death across CKD classes. The incidence of in-hospital, short-term, and mid-term device-related complications did not vary across CKD stages.

CONCLUSIONS

In a nationally representative population of HF and CRT-eligible patients, use of CRT-D was associated with a significantly lower risk of the composite endpoint of HF hospitalization or death among patients with moderate-to-severe CKD in the setting of acceptable complication rates.

Considerations in Patients With Cardiac Implantable Electronic Devices at End of Life

Since the introduction of implantable cardiac pacemakers in 1958 and implantable cardioverter-defibrillators in 1980, these devices have been proven to save and prolong lives. Pacemakers, implantable cardioverter-defibrillators, and cardiac resynchronization therapy are deemed life-sustaining therapies. Despite these life-saving technologies, all patients ultimately will reach the end of their lives from either their heart disease or development of a terminal illness. Clinicians may be faced with patient and family requests to withdraw these life-sustaining therapies. The purpose of this article is to educate clinicians about the legal and ethical principles that underlie withdrawal of life-sustaining therapies such as device deactivation and to highlight the importance of proactive communication with patients and families in these situations.

Association Between Comorbidities and Outcomes in Heart Failure Patients With and Without an Implantable Cardioverter-Defibrillator for Primary Prevention

Background

Implantable cardioverter-defibrillator (ICD) therapy is associated with improved outcomes in patients with heart failure (HF), but whether this association holds among older patients with multiple comorbid illnesses and worse HF burden remains unclear.

Methods and Results

Using the National Cardiovascular Data Registry’s ICD Registry and the Get With The Guidelines–Heart Failure (GWTG-HF) registry linked with Medicare claims, we examined outcomes associated with primary-prevention ICD versus no ICD among HF patients aged ≥65 years in clinical practice. We included patients with an ejection fraction ≤35% who received (ICD Registry) and who did not receive (GWTG-HF) an ICD. Compared with patients with an ICD, patients in the non-ICD group were older and more likely to be female and white. In matched cohorts, the 3-year adjusted mortality rate was lower in the ICD group versus the non-ICD group (46.7% versus 55.8%; adjusted hazard ratio [HR] 0.76; 95% CI 0.69 to 0.83). There was no associated difference in all-cause readmission (HR 0.99; 95% CI 0.92 to 1.08) but a lower risk of HF readmission (HR 0.88; 95% CI 0.80 to 0.97). When compared with no ICD, ICDs were also associated with better survival in patients with ≤3 comorbidities (HR 0.77; 95% CI 0.69 to 0.87) and >3 comorbidities (HR 0.77; 95% CI 0.64 to 0.93) and in patients with no hospitalization for HF (HR 0.75; 95% CI 0.65 to 0.86) and at least 1 prior HF hospitalization (HR 0.69; 95% CI 0.58 to 0.82). In subgroup analyses, there were no interactions between ICD and mortality risk for comorbidity burden (P=0.95) and for prior HF hospitalization (P=0.46).

Conclusion

Among older HF patients, ICDs for primary prevention were associated with lower risk of mortality even among those with high comorbid illness burden and prior HF hospitalization.

A validated risk model for 1-year mortality after primary prevention implantable cardioverter defibrillator placement

OBJECTIVE

We sought to determine survival for patients with heart failure after an implantation of an implantable cardioverter defibrillator (ICD) for primary prevention in the United States and to develop a simple model that would predict mortality risk.

BACKGROUND

Clinical trials have found that patients with heart failure with a 1-year mortality risk near 20% may not benefit from an ICD.

METHODS

We identified patients from the ICD Registry of the National Cardiovascular Disease Registries who underwent ICD implantation for primary prevention from 2007 to 2009. Two risk scores for mortality were developed in 2 cohorts: one limited to those with a B-type natriuretic peptide (BNP) value and a second for all patients. The scores were obtained from derivation datasets and tested in a validation sets using logistic regression models and classification and regression trees.

RESULTS

In a primary prevention population with BNP available (18,725) the 6 variables most predictive of 1-year mortality were age ≥75, BNP ≥700 pg/mL, chronic lung disease, dialysis, blood urea nitrogen ≥30 mg/dL, and systolic blood pressure <120 mmHg. Patients with zero risk factors had a 3.3% one-year mortality compared to a 66.7% one-year mortality for those with all 6 risk factors. Those with ≥3 risk factors (24.0% of the population) had a 25.8% one-year mortality. A second score using a larger cohort that did not consider BNP identified similar risk factors.

CONCLUSIONS

A simple validated risk score can identify patients at high and low risk for death within a year after ICD placement. A large fraction of those currently implanted with an ICD in the United States have a high 1-year mortality and may not benefit from ICD therapy.

Gender and outcomes after primary prevention implantable cardioverter-defibrillator implantation: Findings from the National Cardiovascular Data Registry (NCDR)

BACKGROUND

Clinical trials have demonstrated the benefit of implantable cardioverter-defibrillators (ICDs) for the primary prevention of sudden cardiac death in selected high-risk individuals. Because of small numbers of women enrolled in these trials, outcomes for women after hospital discharge have not been well described. We compared procedure-related complications and outcomes after hospital discharge between men and women undergoing single- or dual-chamber ICD implantation for primary prevention.

METHODS

In patients 65 years or older with Medicare fee-for-service coverage, we identified 38,912 initial implants (25% women) who received single- or dual-chamber ICDs for primary prevention between January 2006 and December 2009 in the NCDR and evaluated gender differences in outcomes.

RESULTS

Women had greater comorbidity and more advanced heart failure (HF) at the time of ICD implantation than did men. Device-related complications, death at 6 months, all-cause readmissions, and HF readmissions at 6 months were significantly more common in women (7.2% vs 4.8%, 6.5% vs 5.6%, 37.2% vs 31.7%, and 14.0% vs 10.0% respectively; P < .001 for all). Women continued to have higher odds of procedural complications (odds ratio [OR] 1.39, 95% CI 1.26-1.53, P < .001), 6-month all-cause readmission (OR 1.22, 95% CI 1.16-1.28, P < .001), and 6-month HF readmission (OR 1.32, 95% CI 1.23-1.42, P < .001), with a trend toward higher 6-month mortality (OR 1.08, 95% CI 0.98-1.20, P = .123), compared with men, after adjusting for differences in baseline characteristics and device type (single vs dual chamber).

CONCLUSIONS

Among older patients receiving ICDs for primary prevention in clinical practice, women experience worse outcomes than do men. Reasons for gender differences in outcomes are poorly understood and require further investigation.

The Effect of Direct Current Stimulation versus T-Wave Shock on Defibrillation Threshold Testing

INTRODUCTION

There are several methods to induce ventricular fibrillation (VF) during defibrillation threshold (DFT) testing. Delivering a shock at a critical time during the T wave (T-shock) is the conventional approach, while delivering a constant direct current voltage (DC stim) from the implantable cardioverter defibrillator is an alternative method. Only a few reports compare VF induction methods. The purpose of this study was to evaluate the effects and safety of DC stim versus T-shock.

METHODS

We retrospectively investigated 414 consecutive patients undergoing DFT testing. We compared the two groups (DC stim and T-shock) with respect to clinical characteristics, electrocardiogram (ECG) changes, and complications.

RESULTS

Ventricular arrhythmia, including ventricular tachycardia (VT) and VF, was induced by DC stim in 93 patients or T-shock in 321 patients. No more than three attempts were performed during one procedure. There was no significant difference in the baseline ECG, induced tachycardia cycle length (TCL), or complications between the two groups. However, the induced TCL was significantly shorter than the clinical TCL regardless of induction method (P = 0.001). Five patients suffered major complications (i.e., electromechanical dissociation or incessant VT). A history of atrial fibrillation was significantly greater in patients with major complications than the others (80% vs 24%, P = 0.004), and was an independent predictor on multivariate analysis.

CONCLUSIONS

There is no significant difference in induced TCL or complications between the DC stim and T-shock. The induced TCL is significantly shorter than clinical TCL regardless of induction method.

Real world effectiveness of primary implantable cardioverter defibrillators implanted during hospital admissions for exacerbation of heart failure or other acute co-morbidities: cohort study of older patients with heart failure

OBJECTIVES

To examine the effectiveness of primary implantable cardioverter defibrillators (ICDs) in elderly patients receiving the device during a hospital admission for exacerbation of heart failure or other acute co-morbidities, with an emphasis on adjustment for early mortality and other factors reflecting healthy candidate bias rather than the effect of the ICD.

DESIGN

Retrospective cohort study.

SETTING

Linked data from the Centers for Medicare and Medicaid Services and American College of Cardiology-National Cardiovascular Data Registry ICD registry, nationwide heart failure registry, and Medicare claims data 2004-09.

POPULATION

23,111 patients aged ≥ 66 who were admitted to hospital for exacerbation of heart failure or other acute co-morbidities and eligible for primary ICDs.

MAIN OUTCOME MEASURES

All cause mortality and sudden cardiac death. Latency analyses with Cox regression were used to derive crude hazard ratios and hazard ratios adjusted for high dimension propensity score for outcomes after 180 days from index implantation or discharge.

RESULTS

Patients who received an ICD during a hospital admission had lower crude mortality risk than patients who did not receive an ICD (40% v 60% at three years); however, with conditioning on 180 day survival and with adjustment for high dimension propensity score, the apparent benefit with ICD was no longer evident for sudden cardiac death (adjusted hazard ratio 0.95, 95% confidence interval 0.78 to 1.17) and had a diminished impact on total mortality (0.91, 0.82 to 1.00). There were trends towards a benefit with ICD in reducing mortality or sudden cardiac death in patients who had had a myocardial infarction more than 40 days previously, left bundle branch block, or low serum B type natriuretic peptide; however, these trends did not reach significance.

CONCLUSION

After adjustment for healthy candidate bias and confounding, the benefits of primary ICD therapy seen in pivotal trials were not apparent in patients aged 66 or over who received ICDs during a hospital admission for exacerbation of heart failure or other acute co-morbidities. Future research is warranted to further identify subgroups of elderly patients who are more likely to benefit from ICDs. Recognition of those patients whose dominant risk factors are from decompensated heart failure and non-cardiac co-morbidities will allow better focus on ICDs in those patients for whom the device offers the most benefit and provides meaningful prolonging of life.

Comparative Effectiveness of Cardiac Resynchronization Therapy Defibrillators Versus Standard Implantable Defibrillators in Medicare Patients

Previous analyses have shown that there is lower mortality with cardiac resynchronization therapy defibrillators (CRT-D) in patients with left bundle branch block (LBBB) but demonstrated mixed results in patients without LBBB. We evaluated the comparative effectiveness of CRT-D versus standard implantable defibrillators (ICDs) separately in patients with LBBB and right bundle branch block (RBBB) using Medicare claims data. Medicare records from CRT-D and ICD recipients from 2002 to 2009 that were followed up for up to 48 months were analyzed. We used propensity scores to match patients with ICD to those with CRT-D. In LBBB, 1:1 matching with replacement resulted in 54,218 patients with CRT-D and 20,763 with ICD, and in RBBB, 1:1 matching resulted in 7,298 patients with CRT-D and 7,298 with ICD. In LBBB, CRT-D had a 12% lower risk of heart failure hospitalization or death (hazard ratio [HR] 0.88, 95% confidence interval 0.86 to 0.90) and 5% lower death risk (HR 0.95, 0.92 to 0.97) compared with ICD. In RBBB, CRT-D had a 15% higher risk of heart failure hospitalization or death (HR 1.15, 1.10 to 1.20) and 13% higher death risk (HR 1.13, 1.07 to 1.18). Sensitivity analysis revealed that accounting for covariates not captured in the Medicare database may lead to increased benefit with CRT-D in LBBB and no difference in RBBB. In conclusion, in a large Medicare population, CRT-D was associated with lower mortality in LBBB but higher mortality in RBBB. The absence of certain covariates, in particular those that determine treatment selection, may affect the results of comparative effectiveness studies using claims data.