Use of implantable cardioverter defibrillators after out-of-hospital cardiac arrest: a prospective follow-up study

ICD Implantation Rates in Cardiac Arrest Survivors in Canada

Background

Patients resuscitated from out-of-hospital cardiac arrest (OHCA) are at high risk of recurrence, posing a substantial burden on healthcare systems. Despite the established benefit of implantable cardioverter defibrillator (ICD) therapy in many such patients, and recommendations by guidelines, few studies have described the proportion of OHCA patients who receive guideline-concordant care.

Methods

The Canadian Institute for Health Information Discharge Abstract Database dataset was used to identify OHCA patients admitted to hospitals across Canada, excluding Quebec. We analyzed all patients without a probable ischemic or bradycardia etiology of cardiac arrest, who survived to discharge, to estimate the ICD implantation rates in patients who were potentially eligible to have an ICD.

Results

Between 2013 and 2017, a total of 10,435 OHCA patients who were admitted to the hospital were captured in the database; 4486 (43%) survived to hospital discharge, and 2580 survivors (57.5%) were potentially eligible to receive an ICD. Among these potentially eligible patients, 757 (29.3%) received an ICD during their index admission or within 30 days after discharge from the hospital. The ICD implantation rate during index admission increased from 13.8% in 2013 to 19.6% in 2017 (P-value for time trend < 0.05). The rate of ICD implantations in potentially eligible patients was higher in urban than in rural settings (19.5% vs 11.1%) and in teaching vs community hospitals (34.7% vs 9.8%).

Conclusions

Although ICD implantation rates show an increasing trend among patients with OHCA who are likely eligible for secondary prevention, significant underutilization of ICDs persists in these patients.

Implantable Cardioverter Defibrillator Implantation Rates After Out of Hospital Cardiac Arrest: Are the Rates Guideline-Concordant?

BACKGROUND

Clinical practice guidelines recommend implantable cardioverter defibrillators (ICDs) for the secondary prevention of sudden death after a cardiac arrest not from a reversible cause, but "real world" implantation rates are not well described.

METHODS

Adults with out of hospital cardiac arrest attended by Emergency Medical Services are captured in the Toronto Regional RescuNET database. We analyzed those who survived to hospital discharge and collected data on age, sex, initial rhythm, ST-elevation myocardial infarction (STEMI) on presenting electrocardiogram (ECG), in-hospital revascularization, neurologic status (Modified Rankin Scale [MRS]) at discharge, and admission hospital type. To estimate 'indicated' ICD implantation rates, "likely ICD-eligible" patients were defined as having an initial shockable rhythm, no STEMI on presenting ECG, no revascularization, and good neurologic status (MRS 0-3). "Not likely ICD-eligible" patients were defined as having a STEMI on presenting ECG, revascularization, or poor neurologic status (MRS 4-5).

RESULTS

In the 1238 adults (2011-2014) analyzed, the overall ICD implantation rate was 23.9%. Two hundred fifty-six patients were "likely ICD-eligible," of whom 146 (57.0%) received an ICD. The implantation rate for "not likely ICD-eligible" patients was 16.7% (112 of 670). ICD eligibility could not be determined for 312 patients, of whom 38 (12.2%) received an ICD. Admission to a hospital with ICD implantation facilities was associated with a higher probability of ICD implantation (odds ratio, 2.85; 95% confidence interval, 1.40-5.82).

CONCLUSIONS

Postcardiac arrest ICD implantation rates in eligible patients are lower than expected. Implementation strategies to monitor guideline adherence after out of hospital cardiac arrest are warranted.

Primary Prevention of Sudden Cardiac Death With Device Therapy in Urban and Rural Populations

BACKGROUND

Implantable cardioverter defibrillators (ICDs) have shown benefit in reducing mortality in patients with heart failure, after myocardial infarction, and those with reduced ejection fraction. We sought to explore the use of this therapy in specialized heart function clinics, in rural and urban locations.

METHODS

This was a retrospective cohort study performed in 3 specialized heart function clinics in Nova Scotia, 2 of which were in rural locations. All patients with an initial left ventricular ejection fraction ≤ 35% were included from 2006 to 2011. Rates of referral, ICD implantation, and mortality were compared between urban and rural groups.

RESULTS

There were 922 patients included in the study; 636 patients in the urban clinic, 286 in the rural locations. Referral rates were higher in the urban clinic compared with the rural locations (80.4% vs 68.3%; P = 0.024). Refusal rates for referral were higher in the rural locations (13.7% vs 2.1%; P < 0.0001). Higher referral rates were associated with urban location (odds ratio [OR], 1.81; 95% confidence interval [CI], 1.01-3.26; P = 0.047), and younger age (OR, 0.96; 95% CI, 0.93-0.99; P = 0.003); lower referral rates for women was observed (OR, 2.29; 95% CI, 1.13-4.63; P = 0.021). Mortality was significantly associated with older age, lack of referral, presence of comorbidities (renal failure, diabetes, peripheral vascular disease) and a rural location.

CONCLUSIONS

Specialized heart function clinics have a high rate of appropriate referral for primary prevention ICDs, but referral rates for this life-saving therapy remain lower in rural jurisdictions. This disparity in access to care is associated with increased mortality and might require particular attention to prevent unnecessary deaths.

Patients, intimate partners and family experiences of implantable cardioverter defibrillators: qualitative systematic review

AIM

This paper is a report of an interpretive review of qualitative research on how an implantable cardioverter defibrillator affects adult recipients and their significant others.

BACKGROUND

An implantable cardioverter defibrillator detects pathological cardiac rhythms and automatically converts the rhythm with electrical counter shocks.

DATA SOURCES

A systematic literature search was conducted for qualitative research papers published between January 1999 and January 2009. PubMed, Medline, ISI Web of Knowledge and CINAHL databases were searched with the following key words: internal defibrillator, implantable defibrillator and qualitative research.

REVIEW METHODS

Twenty-two papers were included. The critical appraisal skills programme and prompts were used to appraise studies. Thematic analysis and synthesis approaches were used to interpret evidence.

FINDINGS

People with an implantable cardioverter defibrillator were found to experience physical, psychological and social changes. Shocks produce fear and anxiety, affecting relationships and sexual relations. The use of support groups and the use of the Internet are important in helping adjustment to an implantable cardioverter defibrillator. Women's responses to an implantable cardioverter defibrillator appear different than men's responses and include concerns about physical appearance and relationship issues. Postdischarge follow-up and educational programmes are still underdeveloped.

CONCLUSION

Patients need additional education, support and follow-up care after hospital discharge. Patients and significant others benefit from collaboration between patient associations and healthcare professional societies. Future research is needed to identify the specific challenges that women recipients face.

[The daily experience of the patient with an implantable cardioverter defibrillator]

OBJECTIVE

To describe the daily experience of patients with an automatic defibrillator (AD) implant and the adaptive changes of the patient.

METHOD

Qualitative and phenomenological research. Collection of data through; initially unstructured interview with half of the informants, semi-structured interviews through an open questions guide after the initial unstructured interviews and use of personal narratives of the informants. Analysis of the data using the Van Manen proposal.

RESULTS

We analysed the interviews of 10 participants. We collected socio-demographic variables and identified the following themes, which respond to the question "How is life with an AD": It is life "with the two sides of the coin," living in constant wait and uncertainty, accepting change, developing adaptation strategies, renegotiating relationships and sexuality and it is to live transformed.

CONCLUSIONS

The results of this study can be integrated into nurse clinical practice in areas such as valuation after discharge, changes in habits, control of treatment, notification of shocks, masking detection of symptoms and strategies that can jeopardise the bearer. Research needs to be developed that looks closer into the influence of other technological devices in people.

Cost-benefit analysis of primary prevention of sudden cardiac death with an implantable cardioverter defibrillator versus amiodarone in Canada

BACKGROUND

Clinical trials have shown that implantable cardioverter defibrillators are effective in primary prevention of sudden cardiac death (SCD) in patients with high risk profiles.

OBJECTIVES

To conduct a cost-benefit assessment of prevention of sudden cardiac death with an implantable cardioverter defibrillator (ICD) vs. amiodarone from the Canadian health-care system perspective.

METHODS

A simulation model that estimates the patient's course following an implantation with an ICD or initiation of amiodarone treatment was created. A thousand pairs of patients with identical characteristics in each treatment group, with similar demographic profiles as observed in the Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT) were simulated. Based on the simulated individual patient characteristics, the model estimated the timing of severe arrhythmic events and deaths due to other causes and implemented the consequences at the time of the events. Patients might die at the time of severe arrhythmia (sudden cardiac death) or survive and become secondary prevention cases and be exposed to a higher risk of severe arrhythmia for the following 6 months. The rates of arrhythmia and death due to other causes were assumed to be the same, whereas the cases of fatality from severe arrhythmia differed between treatments. During the course of the simulation, the clinical (i.e., deaths) and economic outcomes were tallied for both treatment groups. All model parameters were obtained from the literature. The primary data source for clinical inputs was the published results of the SCD-HeFT trial which investigated the impact of ICDs on patients' survival in primary prevention of sudden cardiac deaths compared to amiodarone and conventional therapy. The value of a statistical life (CND$ 5.8 million) was obtained from an analysis previously performed by Health Canada. The direct medical costs and monetary value of lives saved were estimated over 5 years. Sensitivity analyses on key parameters were carried out. The most important study limitation was using two different sources to derive the age dependent clinical risks. This issue was resolved by calibrating the derived risks to account for the population differences.

RESULTS

The model predicted that the overall mortality would be reduced by 19.1% (7.1% absolute reduction) with ICD compared to amiodarone over 5 years. The incremental benefit with ICD was estimated at CND$526,700 and additional cost at CND$28,300, which translated into a 0.05 cost: benefit ratio--around 1: 20 return of investment.

CONCLUSION

In Canada, ICDs are a worthwhile alternative to amiodarone in the primary prevention of sudden cardiac death.

Use of implantable cardioverter defibrillators in Canadian and US survivors of out-of-hospital cardiac arrest

BACKGROUND

Cardiac arrest due to ventricular arrhythmia in the absence of a reversible cause or contraindication has been a class I indication for insertion of an implantable cardioverter defibrillator since 1998. We compared and contrasted the use of implantable cardioverter defibrillator therapy in Canada and the United States among adults who survived a cardiac arrest.

METHOD

Data on hospital separations from April 1, 1994 through March 31, 2003 were obtained from the Health Person-Oriented Information Database maintained by Statistics Canada and from the US National Hospital Discharge Survey on all patients with a primary diagnosis of cardiac arrest, ventricular fibrillation or ventricular flutter for the same 9-year period. We excluded all records of patients with a secondary diagnosis of acute myocardial infarction.

RESULTS

In Canada, 3793 patients survived to discharge after a cardiac arrest; 628 (16.6%) of these were implanted with a cardioverter defibrillator before discharge. The implant rate rose steadily from 5.4% in 1994/95 to 26.7% in 2002/03. In the United States, 23 688 (30.2%) of 78 538 such survivors received an implantable cardioverter defibrillator before discharge. Logistic regression analysis indicated that sex, age, fiscal year, the hospital's teaching status, hospital size and patient history of heart failure were positive predictors of implantable cardioverter defibrillator implantation. Age, renal failure, liver failure and cancer were negative predictors of receiving an implantable cardioverter defibrillator.

INTERPRETATION

The rate of use of implantable cardioverter defibrillator therapy for cardiac arrest survivors in Canada is increasing, but still is lower than the rate in the United States.

Cost-benefit analysis of preventing sudden cardiac deaths with an implantable cardioverter defibrillator versus amiodarone

OBJECTIVES

To conduct a cost-benefit assessment of prevention of sudden cardiac deaths with an implantable cardioverter defibrillator (ICD) versus amiodarone from the perspective of the health-care systems in the UK and France.

METHODS

Course after implantation with an ICD or taking amiodarone was modeled using discrete event simulation; 1000 pairs of identical patients were simulated 100 times for each analysis. Rates of life-threatening arrhythmia and death from other causes were assumed identical, but the case fatality of arrhythmia and hospitalization differ between treatments. Rates were based on published data, primarily from the Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT). Direct medical costs (in 2004 Euros) and lives saved were estimated over 5 years. The monetary value of a life (UK euro2.1 million, France euro2.0 million) was applied to this benefit and examined relative to the net investment required.

RESULTS

ICDs decreased deaths during the 5 years from 37.0% to 29.7% at a net cost of euro26,222 to euro20,008 per patient, yielding cost-benefit ratios of 0.17 (UK) and 0.14 (France)-more than a 5 to 1 return on investment. Sensitivity analyses showed ICDs represent value for money whenever a life is valued at least at euro274,000.

CONCLUSION

In these European countries where society values a life at more than euro2 million, ICDs are a worthwhile investment compared with amiodarone for primary prevention of sudden cardiac deaths in patients with heart failure.

International Resuscitation Network Registry: design, rationale and preliminary results

There is a lack of high-quality information about the effectiveness of resuscitation interventions and international differences in structure, process and outcome after out-of-hospital cardiac arrest and cardiopulmonary resuscitation because data are not collected uniformly. An internet-based international registry could make such evaluations possible, and enable the conduct of large randomized controlled trials of resuscitation therapies. A prospective international cohort study was performed that included 571 infants, children and adults (a) who experienced cardiac arrest requiring chest compressions or external defibrillation, (b) outside the hospital in the study communities and (c) upon whom resuscitation was attempted by EMS personnel. Cardiac arrest was defined as lack of responsiveness, breathing or movement in individuals for whom the EMS system is activated for whom an arrest record is completed. All data were collated via a secure and confidential web-based method by using automated forms processing software with appropriate variable range checks, logic checks and skip rules. Median number of missing responses for each variable was 0 (interquartile range 0, 0). Twenty-seven percent of the patients had a first recorded rhythm of ventricular fibrillation or ventricular tachycardia, 60% had a witnessed arrest, and 34% received bystander CPR. Mean time from call to arrival on scene was 7.1+/-5.1 min. Six percent of the patients survived to hospital discharge. The resuscitation process was highly variable across centers, and survival and neurological outcome were also significantly and independently different across centers. This study shows that it is possible to collect data prospectively describing the structure, process and outcome associated with cardiac arrest in multiple international sites via the internet. Therefore, it is feasible to conduct adequately powered randomized trials of resuscitation therapies in international settings.