Impact of advanced age on survival in patients with implantable cardioverter defibrillators

Usefulness of the MADIT-ICD Benefit Score in a Large Mixed Patient Cohort of Primary Prevention of Sudden Cardiac Death

Background: Decision-making in primary prevention is not always trivial and many clinical scenarios are not reflected in current guidelines. To help evaluate a patient’s individual risk, a new score to predict the benefit of an implantable defibrillator (ICD) for primary prevention, the MADIT-ICD benefit score, has recently been proposed. The score tries to predict occurrence of ventricular arrhythmias and non-arrhythmic death based on data from four previous MADIT trials. We aimed at examining its usefulness in a large single-center register of S-ICD patients with various underlying cardiomyopathies. Methods and results: All S-ICD patients with a primary preventive indication for ICD implantation from our large single-center database were included in the analysis (n = 173). During a follow-up of 1227 ± 978 days, 27 patients developed sustained ventricular arrhythmias, while 6 patients died for non-arrhythmic reasons. There was a significant correlation for patients with ischemic cardiomyopathy (ICM) (n = 29, p = 0.04) to the occurrence of ventricular arrhythmia. However, the occurrence of ventricular arrhythmias could not sufficiently be predicted by the MADIT-ICD VT/VF score (p = 0.3) in patients with (n = 142, p = 0.19) as well as patients without structural heart disease (n = 31, p = 0.88) and patients with LV-EF < 35%. Of the risk factors included in the risk score calculation, only non-sustained ventricular tachycardias were significantly associated with sustained ventricular arrhythmias (p = 0.02). Of note, non-arrhythmic death could effectively be predicted by the proposed non-arrhythmic mortality score as part of the benefit score (p = 0.001, r = 0.3) also mainly driven by ICM patients. Age, diabetes mellitus, and a BMI < 23 kg/m2 were key predictors of non-arrhythmic death implemented in the score. Conclusion: The MADIT-ICD benefit score adds a new option to evaluate expected benefit of ICD implantation for primary prevention. In a large S-ICD cohort of primary prevention, the value of the score was limited to patients with ischemic cardiomyopathy. Future research should evaluate the performance of the score in different subgroups and compare it to other risk scores to assess its value for daily clinical practice.

Primary results from the Japanese Heart Failure and Sudden Cardiac Death Prevention Trial (HINODE)

Aims

The HINODE study aimed to analyse rates of mortality, appropriately treated ventricular arrhythmias (VA), and heart failure in Japanese patients and compared with those in Western patients.

Methods and results

After treatment decisions following contemporary practice in Japan, patients were prospectively enrolled into four cohorts: (i) internal cardioverter‐defibrillator (ICD), (ii) cardiac resynchronization therapy (CRT) defibrillator (CRT‐D), (iii) standard medical therapy (‘non‐device’: ND), or (iv) pacing (indicated for CRT; received pacemaker or CRT pacing). Cohorts 1–3 required a left ventricular ejection fraction ≤35%, a history of heart failure, and a need for primary prevention of sudden cardiac death based on two to five previously identified risk factors. Endpoint outcomes were adjudicated by the independent committees. ICD and CRT‐D cohorts, considered as high‐voltage (HV) cohorts, were pooled for Kaplan–Meier analysis and propensity‐matched to Multicenter Automatic Defibrillator Implantation Trial‐Reduce Inappropriate Therapy (MADIT‐RIT) arm B and C patients. The study enrolled 354 patients followed for 19.6 ± 6.5 months, with a minimum of 12 months. Propensity‐matched HV cohorts showed comparable VA (P = 0.61) and mortality rates (P = 0.29) for HINODE and MADIT‐RIT. The ND cohort presented a high crossover rate to ICD therapy (6.1%, n = 7/115), and the CRT‐D cohort showed elevated mortality rates. The pacing cohort revealed that patients implanted with pacemakers had higher mortality (26.0%) than those with CRT‐Pacing (8.4%, P = 0.05).

Conclusions

The mortality and VA event rates of landmark trials are applicable to patients with primary prevention in Japan. Patients who did not receive guideline‐indicated CRT devices had poor outcomes.

Cardiac Implantable Electronic Devices: Reoperations and the Competing Risk of Death

BACKGROUND

The use of cardiac implantable electronic devices (CIED), which includes pacemakers, implantable cardioverter-defibrillators (ICD), cardiac resynchronisation therapy pacemakers (CRT-P) and cardiac resynchronisation therapy defibrillators (CRT-D) has increased over the past 20 years, but there is a lack of real world evidence on the longevity of these devices in the older population which is essential to inform health care delivery and support clinical decisions.

METHODS AND RESULTS

We conducted a retrospective cohort study using data from the Australian Government Department of Veterans' Affairs database. The cohort consisted of people who had a CIED procedure between 2005 and 2015. The cumulative risk of generator replacement/reoperations was estimated accounting for the competing risk of death. A total of 16,662 patients were included. In pacemaker recipients with an average age of 85 years, the 5-year risk of reoperation ranged from 2.8% in single chamber, 3.6% in dual chamber to 7.6% in CRT-P recipients, while the 5-year risk of dying with the index pacemaker in situ was 63% in single chamber, 46% in dual chamber and 56% in CRT-P recipients. In defibrillator recipients with an average age of 80 years, the 5-year risk of reoperation ranged from 11% in single chamber, 13% in dual chamber to 24% in CRT-D recipients, while the 5-year risk of dying with the index defibrillator in situ was 46% in single chamber, 40% in dual chamber and 41% in CRT-D recipients.

CONCLUSION

In this cohort of older patients the 5-year risk of generator reoperation was low in pacemaker recipients whereas up to one in four CRT-D recipients would have a reoperation within 5 years.

Implantable cardioverter-defibrillators in elderly patients: outcome and predictors of mortality

PURPOSE

The implantable cardioverter-defibrillator (ICD) is the therapy of choice for the prevention of sudden cardiac death. The number of elderly patients receiving ICDs is increasing. This study aimed to assess the outcome of patients according to their age at the time of implantation, and to identify variables potentially associated with patient survival.

METHODS

Between June 2009 and December 2019, we retrospectively enrolled all consecutive patients in whom ICD implantation had been performed for primary or secondary prevention at our center.

RESULTS

During the study period, 670 patients underwent ICD implantation. We stratified the population into four age-classes: Class 1 (23%) (pts aged less than 60 years), Class 2 (28%) (pts aged between 60 and 70 years), Class 3 (39%) (pts aged between 70 and 80 years) and Class 4 (9%) (pts aged 80 years or older). Over a median follow-up of 42 months, the rate of deaths in Class 4 was higher than in Classes 1 and 2 (log-rank test, P < 0.01), but was comparable to that in Class 3 (P = 0.407). With increasing age, we observed more complications at the time of implantation and during follow-up. On multivariate analysis, higher NYHA class, creatinine level and CHA₂DS₂-VASc score were identified as independent predictors of death, while age was not associated with worse prognosis. Higher body mass index, higher NYHA class and CHA₂DS₂-VASc score were also confirmed as independent predictors of hospitalizations or death due to any cause.

CONCLUSION

This study showed good survival in ICD patients in all age-groups, including those aged ≥80 years. The CHA₂DS₂-VASc score seems to be a stronger predictor of death than age.

Predicted benefit of an implantable cardioverter-defibrillator: the MADIT-ICD benefit score

AIMS

The benefit of prophylactic implantable cardioverter-defibrillator (ICD) is not uniform due to differences in the risk of life-threatening ventricular tachycardia (VT)/ventricular fibrillation (VF) and non-arrhythmic mortality. We aimed to develop an ICD benefit prediction score that integrates the competing risks.

METHODS AND RESULTS

The study population comprised all 4531 patients enrolled in the MADIT trials. Best-subsets Fine and Gray regression analysis was used to develop prognostic models for VT (≥200 b.p.m.)/VF vs. non-arrhythmic mortality (defined as death without prior sustained VT/VF). Eight predictors of VT/VF (male, age < 75 years, prior non-sustained VT, heart rate > 75 b.p.m., systolic blood pressure < 140 mmHg, ejection fraction ≤ 25%, myocardial infarction, and atrialarrhythmia) and 7 predictors of non-arrhythmic mortality (age ≥ 75 years, diabetes mellitus, body mass index < 23 kg/m2, ejection fraction ≤ 25%, New York Heart Association ≥II, ICD vs. cardiac resynchronization therapy with defibrillator, and atrial arrhythmia) were identified. The two scores were combined to create three MADIT-ICD benefit groups. In the highest benefit group, the 3-year predicted risk of VT/VF was three-fold higher than the risk of non-arrhythmic mortality (20% vs. 7%, P < 0.001). In the intermediate benefit group, the difference in the corresponding predicted risks was attenuated (15% vs. 9%, P < 0.01). In the lowest benefit group, the 3-year predicted risk of VT/VF was similar to the risk of non-arrhythmic mortality (11% vs. 12%, P = 0.41). A personalized ICD benefit score was developed based on the distribution of the two competing risks scores in the study population (https://is.gd/madit). Internal and external validation confirmed model stability.

CONCLUSIONS

We propose the novel MADIT-ICD benefit score that predicts the likelihood of prophylactic ICD benefit through personalized assessment of the risk of VT/VF weighed against the risk of non-arrhythmic mortality.

Cardiac resynchronization therapy using a pacemaker or a defibrillator: Patient selection and evidence to support it

Cardiac resynchronization therapy (CRT) is an established treatment for patients with heart failure (HF), myocardial dysfunction and prolonged ventricular depolarization on surface electrocardiogram. CRT can be delivered by a pacemaker (CRT-P) or a combined pacemaker-defibrillator (CRT-D). Although these two types of devices are very different in size, function, and cost, current published guidelines do not distinguish between them, leaving the choice of which device to implant to the treating physician and the informed patient. In this paper, we review the published CRT clinical trial literature with focus on the outcomes of HF patients treated with CRT-P versus CRT-D. We also attempt to provide guidance as to the appropriate choice of CRT device type, in the absence of randomized prospective trials geared to answer this specific question.

Comparison of pharmacological treatment alone vs. treatment combined with implantable cardioverter defibrillator therapy in patients older than 75 years

Aims

Implantable cardioverter defibrillator (ICD) reduces mortality in selected patients. However, its role in patients older than 75 years is not well established.

Methods and results

We performed a retrospective, non‐randomized study using a historical cohort from a single centre. Between January 2008 and July 2014, we assessed patients aged ≥75 years with left ventricular ejection fraction ≤ 35%, identifying 385 patients with a Class I or IIa recommendation for ICD implantation. At the decision of the patient or attending cardiologists, 92 patients received an ICD. To avoid potential confounding factors, we used propensity‐score matching. Finally, 126 patients were included (63 with ICD). The mean age was 79.1 ± 3.1 years (86.5% male). As compared with the medical therapy group, the ICD patients had a lower percentage of chronic obstructive pulmonary disease (19.0% vs. 38.1%, P < 0.05) and more frequent use of beta‐blockers (BBs) (85.7 vs. 70.0%, P < 0.05). Other treatments were otherwise similar in both groups. There were no differences related to age, aetiology, or other co‐morbidities. During follow‐up (39.2 ± 22.4 months), total mortality was 46.0% and cardiovascular events (death or hospitalization) occurred in 66.7% of the patients. A multivariate analysis revealed that only BB therapy was shown to be an independent protective variable with respect to mortality [hazard ratio 0.4 (0.2–0.7)]. ICD therapy did not reduce overall mortality or the rate of cardiovascular events.

Conclusions

According to our results, the use of ICD, as compared with medical therapy, in patients older than 75 years did not demonstrate any benefit. Well‐designed randomized controlled studies in patients older than 75 years are needed to ascertain the value of ICD therapy.

Influence of patients' age at implantation on mortality and defibrillator shocks

Aims

Patients have increasing comorbidities and competing causes of death with advancing age, raising questions about the effectiveness of the implantable cardioverter defibrillators (ICD) in older age. We therefore investigated the effect of patients' age at initial device implantation on all-cause mortality and on the risk of ICD shocks in single-chamber (V-ICD), dual-chamber (D-ICD), and cardiac resynchronization therapy defibrillator (CRT-D) recipients.

Methods and results

We reviewed de-identified records of 67 128 ICD recipients enrolled in the Boston Scientific ALTITUDE database of remote monitored patients [V-ICD (n = 11 422), D-ICD (n = 23 974), and CRT-D (n = 31 732)]. Over a mean follow-up of 2.3 ± 1.4 years, patients in all ICD groups had increased all-cause mortality but decreased risk of defibrillator shocks and/or anti-tachycardia pacing per 10 year increase in age. Compared with the youngest age group (<50 years), patients in the oldest age group (≥80 years) had a 6.8-fold, 5.9-fold, and 3.4-fold increase in all-cause mortality (P < 0.001 for all comparisons) and a 31, 45, and 53% decrease in the risk of ICD shock (P ≤ 0.002 for all comparisons) for the V-ICD, D-ICD, and CRT-D groups, respectively.

Conclusion

Older recipients of standard and CRT defibrillators have higher mortality but fewer ICD shocks and/or therapies compared with younger patients. These data highly suggest less benefit of ICD therapy with increasing age, presumably because of competing risks of non-arrhythmic mortality. The role of defibrillator therapy in older patients may need to be evaluated with randomized controlled trials.

Implantable cardioverter-defibrillator in the elderly: Predictors of appropriate interventions and mortality at 12-month follow-up

BACKGROUND

The effectiveness of implantable cardioverter-defibrillator (ICD) in the elderly is uncertain, given their competing risk of nonarrhythmic death. Guidelines state that an ICD should be implanted if the expectation of survival is at least 1 year. However, survival is not easy to predict in elderly patients with severe cardiac disease.

AIM

To assess 12-month survival after ICD implantation in patients aged ≥75 years, to identify predictors of 12-month mortality, and to evaluate the incidence of ICD therapy during follow-up.

METHODS

We retrospectively analyzed all clinical, instrumental, and survival data of patients ≥75 years old who received an ICD in our center from 2000 to 2013.

RESULTS

We included 127 patients (mean age 78 years). ICD was implanted for primary prevention in 61%. The 12-month survival rate was 87.4%. At both univariate and multivariate analyses, left ventricular ejection fraction (EF) ≤ 25%, and moderate to severe impaired renal function (IRF) independently predicted 12-month mortality that was as high as 45.5% in patients with both risk factors. During a median follow-up of 38 months, 30 patients (23.6%) received ≥1 appropriate ICD interventions, but only 3.1% of shocks occurred during the first year, and none in the subgroup of patients with EF ≤ 25% and IRF.

CONCLUSION

Twelve-month survival in elderly patients after ICD implantation is good and the indication for ICD should not be based on age alone. However, the subgroup with EF ≤ 25% and IRF showed a high 12-month nonarrhythmic mortality and did not benefit from ICD implantation.

Guidance on reuse of cardio-vascular catheters and devices in India: A consensus document

Reuse of medical device is accepted worldwide. Benefits of reuse include not only cost saving but a favorable impact on environment. However, certain requirements should be met for reuse to be safe and effective. The devices, which can be reused, should be clearly defined, a meticulous process for dis-infection and sterilization followed and its functionality ascertained before use. Further, an appropriate consent should be obtained where necessary and the cost saving entailed should be directly passed on to the patient.

Position paper for management of elderly patients with pacemakers and implantable cardiac defibrillators: Groupe de Rythmologie et Stimulation Cardiaque de la Société Française de Cardiologie and Société Française de Gériatrie et Gérontologie

Despite the increasingly high rate of implantation of pacemakers (PMs) and implantable cardioverter defibrillators (ICDs) in elderly patients, data supporting their clinical and cost-effectiveness in this age stratum are ambiguous and contradictory. We reviewed the data regarding the applicability, safety and effectiveness of conventional pacing, ICDs and cardiac resynchronization therapy (CRT) in elderly patients. Although periprocedural risk may be slightly higher in the elderly, the implantation procedure for PMs and ICDs is still relatively safe in this age group. In older patients with sinus node disease, the general consensus is that DDD pacing with the programming of an algorithm to minimize ventricular pacing is preferred. In very old patients presenting with intermittent or suspected atrioventricular block, VVI pacing may be appropriate. In terms of correcting potentially life-threatening arrhythmias, the effectiveness of ICD therapy is similar in older and younger individuals. However, the assumption of persistent ICD benefit in the elderly population is questionable, as any advantageous effect of the device on arrhythmic death may be attenuated by higher total non-arrhythmic mortality. While septuagenarians and octogenarians have higher annual all-cause mortality rates, ICD therapy may remain effective in selected patients at high risk of arrhythmic death and with minimum comorbidities despite advanced age. ICD implantation among the elderly, as a group, may not be cost-effective, but the procedure may reach cost-effectiveness in those expected to live more than 5-7years after implantation. Elderly patients usually experience significant functional improvement after CRT, similar to that observed in middle-aged patients. Management of CRT non-responders remains globally the same, while considering a less aggressive approach in terms of reinterventions (revision of left ventricular [LV] lead placement, addition of a right ventricular or LV lead, LV endocardial pacing configuration). Overall, physiological age, general status and comorbidities rather than chronological age per se should be the decisive factors in making a decision about device implantation selection for survival and well-being benefit in elderly patients.

Implantable cardioverter-defibrillators in the elderly: rationale and specific age-related considerations

Despite the increasingly high rate of implantation of cardioverter-defibrillators (ICD) in elderly patients, data supporting their clinical and cost-effectiveness in this age stratum are ambiguous and contradictory. We comprehensively reviewed the state-of-the-art data regarding the applicability, safety, clinical- and cost-effectiveness of the ICD in elderly patients, and analysed which patients in this age stratum are more likely to get a survival benefit from this therapy. Although peri-procedural risk may be slightly higher in the elderly, this procedure is still relatively safe in this age group. In terms of correcting potentially life-threatening arrhythmias, the effectiveness of ICD therapy is comparable in older and younger individuals. However, the assumption of persistent ICD benefit in the elderly population is questionable, as any advantage of the device on arrhythmic death may be largely attenuated by a higher total non-arrhythmic mortality. While septuagenarians and octogenarians have higher annual all-cause mortality rates, ICD therapy may remain effective in highly selected patients at high risk of arrhythmic death and with minimum comorbidities despite advanced age. ICD intervention among the elderly, as a group, may not be cost-effective, but the procedure may reach cost-effectiveness in those expected to live >5-7 years after implantation. Biological age rather than chronological age per se should be the decisive factor in making a decision on ICD selection for survival benefit.

Peripheral artery disease is an independent predictor of mortality after implantable cardioverter-defibrillator implantation in patients with severe left ventricular dysfunction

The impact of peripheral artery disease (PAD) on survival in implantable cardioverter defibrillator (ICD) patients is poorly understood. Thus, we assessed the risk of PAD in our adult ICD patients with left ventricular dysfunction (ejection fraction [EF] ≤35%). Survival was estimated with Kaplan-Meier method and compared by the log-rank test; a Cox proportional hazards model assessed the effects of clinical variables on survival. Average age and EF of 1399 patients were 67.0 ± 12.1 years and 23.8% ± 7.2%, respectively. The ICD patients with PAD had significantly worse survival than those without (unadjusted P < .0001). The multivariate predictors of survival at implant were (hazard ratio, HR [95% confidence interval]) age (HR 1.05 [1.04-1.07] P < .0001), PAD (HR 2.07 [1.53-2.80] P < .0001), class III/IV heart failure (HR 1.36 [1.06-1.76] P = .016), creatinine 1.4-2.0 mg/dL (HR 1.36 [1.05-1.76] P = .019), and creatinine ≥2.0 mg/dL (HR 2.01 [1.42-2.85] P < .0001). The PAD is an independent predictor of mortality and should be considered in the preimplant risk assessment.

Consideration of patient age and life expectancy in implantable cardioverter-defibrillator referral

BACKGROUND

Primary prevention implantable cardioverter-defibrillator (ICD) guidelines recommend device consideration for at-risk patients with a life expectancy of greater than 1 year regardless of age. We sought to assess the influence of patient age and prognosis on ICD referral.

METHODS

A survey was mailed to a random, national sample of 3,000 physicians in the specialties of cardiology, family medicine, and internal medicine. Participants were asked focused questions regarding patient age, life expectancy, and ICD referral.

RESULTS

The overall response rate was 64%. More than one quarter of physicians (n = 386 [27%], 95% CI 25%-30%) withhold primary prevention ICD referral solely because of patient age. Life expectancy is not considered by 23% (n = 324, 95% CI 20%-25%) of physicians before referral, whereas 13% (n = 144, 95% CI 11%-15%) refer patients with a prognosis of less than 1 year. Providers who refer patients for ICD implantation with a life expectancy of less than 1 year are less likely to be cardiologists (odds ratio [OR] 0.50, 95% CI 0.32-0.79, P = .003), are less often affiliated with a teaching hospital (OR 0.62, 95% CI 0.41-0.94, P = .025), and have a greater number of years in practice (OR 1.25 for each 10 years in practice, 95% CI 1.03-1.51, P = .026). Only a minority (n = 315 [22%], 95% CI 20%-24%) of physicians use a life expectancy threshold of 1 year to guide ICD referral.

CONCLUSION

Physicians frequently withhold ICD referral because of patient age. The referral of patients with a prognosis of less than 1 year or without consideration of life expectancy is common.

Do patients at high risk of nonsudden cardiac death benefit from prophylactic ICD therapy?

PURPOSE OF REVIEW

Randomized controlled trials have established that prophylactic implantable cardioverter defibrillator (ICD) therapy improves survival in patients with reduced left ventricular ejection fraction (LVEF). However, mortality reduction is not uniform across the implanted population and recent data have highlighted the importance of nonsudden cardiac death (non-SCD) risk in predicting benefit from ICD therapy. This review explores the importance of non-SCD risk in patient selection for prophylactic ICD therapy, as well as the proposed approaches to identify potential ICD recipients at high risk of non-SCD.

RECENT FINDINGS

Data from randomized controlled trials have demonstrated that patients at high risk of non-SCD do not gain significant survival benefit from prophylactic ICD therapy irrespective of their risk of SCD. A variety of strategies to identify low LVEF patients at high risk of non-SCD have been proposed. These include the use of individual risk markers, such as advanced age and renal dysfunction, the presence of cardiac and noncardiac comorbidities, and the use of more complex risk scores.

SUMMARY

Non-SCD risk is an important issue in patient selection for prophylactic ICD therapy. However, the optimal strategy to identify patients at high non-SCD risk is unclear and further research is needed.

Comparison of benefit and mortality of implantable cardioverter-defibrillator therapy in patients aged ≥75 years versus those <75 years

Implantable cardioverter-defibrillator (ICD) therapy decreases arrhythmic and all-cause mortality in patients at high risk of sudden death. However, its clinical benefit in elderly patients is uncertain. The aim of this study was to assess the long-term efficacy of ICD treatment in elderly patients and to identify markers of successful ICD therapy and risk factors of mortality. We performed multivariate analysis of a prospective long-term database from 2 tertiary care centers including 936 consecutive patients with an ICD. Predictors of ICD therapy and risk factors for mortality were assessed in patients ≥75 years old at ICD implantation compared to younger patients. Mean follow-up time was 43 ± 40 months. Rates of ICD therapy were similar in the 2 age groups. No significant predictors of ICD therapy could be identified in older patients. Median estimated survival was 132 months in patients <75 years and 81 months in those ≥75 years old (p = 0.006). Decreased ejection fraction (hazard ratio 1.62 per 10% decrease, p = 0.03) and impaired renal function (hazard ratio 1.57 per 10 ml/kg/m(2) decrease in estimated glomerular filtration rate, p = 0.02) were independent risk factors of mortality in patients ≥75 years old. However, mortality of older patients was similar to that of the age-matched general population irrespective of delivery of ICD therapy. In conclusion, ICD therapy is effective for treatment of life-threatening arrhythmias in all age groups. However, prevention of sudden cardiac death may have limited impact on overall mortality in older patients. Despite a similar rate of appropriate ICD therapies, risk of death is increased 1.6-fold in ICD recipients ≥75 years old compared to younger patients. Patients with decreased ejection fraction and impaired renal function are at highest risk.

Health care utilisation after defibrillator implantation for primary prevention according to the guidelines in 2 Dutch academic medical centres

Background

The benefit of implantable defibrillators (ICDs) for primary prevention remains debated. We analysed the implications of prophylactic ICD implantation according to the guidelines in 2 tertiary hospitals, and made a healthcare utilisation inventory.

Methods

The cohort consisted of all consecutive patients with coronary artery disease (CAD) or dilated cardiomyopathy (DCM) receiving a primary prophylactic ICD in a contemporary setting (2004–2008). Follow-up was obtained from hospital databases, and mortality checked at the civil registry. Additional data came from questionnaires sent to general practitioners.

Results

There were no demographic differences between the 2 centres; one had proportionally more CAD patients and more resynchronisation therapy (CRT-D). The 587 patients were followed over a median of 28 months, and 50 (8.5%) patients died. Appropriate ICD intervention occurred in 123 patients (21%). There was a small difference in intervention-free survival between the 2 centres. The questionnaires revealed 338 hospital admissions in 52% of the responders. Device-related admissions happened on 68 occasions, in 49/276 responders. The most frequently reported ICD-related admission was due to shocks (20/49 patients); for other cardiac problems it was mainly heart failure (52/99). Additional outpatient visits occurred in 19%.

Conclusion

Over a median follow-up of 2 years, one fifth of prophylactic ICD patients receive appropriate interventions. A substantial group undergoes readmission and additional visits. The high number of admissions points to a very ill population. Overall mortality was 8.5%. The 2 centres employed a similar procedure with respect to patient selection. One centre used more CRT-D, and observed more appropriate ICD interventions.

Elevated γ-glutamyltransferase in implantable cardioverter defibrillator patients

BACKGROUND

Elevated γ-glutamyltransferase (GGT) is a new risk factor for cardiovascular diseases, but its impact on ventricular tachyarrhythmia occurrence and survival in patients with an implantable cardioverter defibrillator (ICD) is unknown.

METHODS AND RESULTS

Considering that GGT levels are gender-dependent, female ICD recipients were excluded from our database because of the low incidence of events. In a retrospective analysis, appropriate ICD therapy (both shocks and antitachycardia pacing due to ventricular tachyarrhythmias) occurred in 31.9% of 320 male patients who had received an ICD for primary prevention (median follow-up of 2.3 years), and in 55.1% of 423 male patients who had received an ICD for secondary prevention (median follow-up of 3.9 years). Compared to normal low GGT plasma levels (below 28 U/L), total mortality but not risk for appropriate ICD therapy was elevated for higher GGT categories (p for trend = 0.004 in primary prevention and p for trend = 0.002 in secondary prevention, respectively). In Cox regression analysis, elevated GGT (>56 U/L) remained an independent predictor of death both in primary (p = 0.011) and in secondary prevention (p = 0.006). Patients with elevated GGT and renal insufficiency defined by an estimated glomerular filtration rate <60 ml/min/1.73 m(2) suffered from excess total mortality jeopardizing the benefit of ICD therapy.

CONCLUSION

Elevation of GGT is an important adverse prognostic parameter in ICD patients. A possible role of GGT for improved patient selection for ICD therapy deserves further investigation.

Cost-effectiveness of implantable defibrillators after myocardial infarction based on 8-year follow-up data (MADIT II)

OBJECTIVES

About 190,000 Germans experience a myocardial infarction each year. Of these, 25% may be eligible for an implantable cardioverter defibrillator (ICD) due to low left ventricular ejection fraction. Given the high costs of implantation, the purpose of this study was to assess the cost-effectiveness of ICDs compared to conventional therapy in patients with an ejection fraction 30% or less after MI in Germany.

METHODS

The economic evaluation was performed from the perspective of the German statutory health insurance. To simulate costs and effectiveness over lifetime, a Markov model was constructed with seven health states. The model was based on 8-year follow-up data for ICD implantation after myocardial infarction (MADIT II), which was published recently.

RESULTS

The analysis shows that ICD implantation compared to conventional therapy in patients fulfilling MADIT-II criteria has a cost-effectiveness ratio of €44,736 per quality-adjusted life year gained. If every patient insured by the statutory health insurance and fulfilling the MADIT-II criteria would receive an ICD, the model suggests expenditures between €173 million and €1.7 billion per year.

CONCLUSIONS

ICD therapy cannot be considered clearly cost-effective when compared to many well-accepted interventions. If policy makers decide to reimburse ICDs in the MADIT-II population, they will need to either raise premiums or abandon coverage for other currently funded medical interventions.

Effectiveness of implantable defibrillators in octogenarians and nonagenarians for primary prevention of sudden cardiac death

Given their advanced age and frequent co-morbidities, it is unclear whether octogenarians and nonagenarians with decreased left ventricular ejection fraction (LVEF) derive a survival benefit from implantable cardioverter-defibrillators (ICDs) in the primary prevention setting. The purpose of this study was to examine the effect of ICDs, age, and multiple co-morbidities on survival in elderly patients who otherwise meet implantation criteria for primary prevention of sudden cardiac death. Patients ≥80 years of age who received an ICD for LVEF ≤35% at our institution from 2001 through 2008 (n = 99) were compared to a cohort of patients ≥80 years of age with similarly low LVEF who did not receive an ICD (n = 53). Co-morbid conditions were assessed using the Charlson co-morbidity index (CCI). The overall cohort (n = 152, 84 ± 4 years old, 72% men, 87% with ischemic cardiomyopathy, LVEF 25 ± 7%, CCI 5.9 ± 3.2) was followed for 2.3 ± 2.0 years. Patients with ICDs were younger (82 ± 3 vs 86 ± 4 years, p <0.001) and had fewer co-morbidities reflected in a lower CCI (5.3 ± 3.1 vs 6.7 ± 3.1, p = 0.021). Patients with ICDs also had a trend toward lower LVEF (24 ± 6% vs 27 ± 7%, p = 0.06). During follow-up 93 (61%) patients died, 58 (59%) in the ICD group and 35 (66%) in the no-ICD group. ICD recipients had better 1-year survival compared to patients with no ICD (72% vs 52%, p = 0.014). However, after adjusting for age, LVEF, glomerular filtration rate (GFR), and CCI using multivariate Cox models, an ICD did not confer any survival benefit (hazard ratio 0.71, 95% confidence interval 0.42 to 1.20, p = 0.20), whereas age (p = 0.043) and GFR (p = 0.006) were the only independent predictors of survival. In conclusion, age and GFR are the main determinant of survival in octogenarians and nonagenarians with LV dysfunction. After correcting for these parameters, an ICD does not appear to confer a survival benefit.

Influence of age on perioperative complications among patients undergoing implantable cardioverter-defibrillators for primary prevention in the United States

BACKGROUND- The majority of current implantable cardioverter-defibrillator (ICD) recipients are significantly older than those in the ICD trials. Data on periprocedural complications among the elderly are insufficient. We evaluated the influence of age on perioperative complications among primary prevention ICD recipients in the United States. METHODS AND RESULTS- Using the National Cardiovascular Data's ICD Registry, we identified 150 264 primary prevention patients who received ICDs from January 2006 to December 2008. The primary end point was any adverse event or in-hospital mortality. Secondary end points included major adverse events, minor adverse events, and length of stay. Of 150 264 patients, 61% (n=91 863) were 65 years and older. A higher proportion of patients ≥65 years had diabetes, congestive heart failure, atrial fibrillation, renal disease, and coronary artery disease. Approximately 3.4% of the entire cohort had any complication, including death, after ICD implant. Any adverse event or death occurred in 2.8% of patients under 65 years old; 3.1% of 65- to 69-year-olds; 3.5% of 70- to 74-year-olds; 3.9% of 75- to 79-year-olds, 4.5% of 80- to 84-year-olds; and 4.5% of patients 85 years and older. After adjustment for clinical covariates, multivariate analysis found an increased odds of any adverse event or death among 75- to 79-year-olds (1.14 [95% confidence interval, 1.03 to 1.25], 80-to 84-year-olds (1.22 [95% confidence interval, 1.10 to 1.36], and patients 85 years and older (1.15 [95% confidence interval, 1.01 to 1.32], compared with patients under 65 years old. CONCLUSIONS- Older patients had a modestly increased-but acceptably safe-risk of periprocedural complications and in-hospital mortality, driven mostly by increased comorbidity.

Bundle-branch block morphology and other predictors of outcome after cardiac resynchronization therapy in Medicare patients

BACKGROUND

Clinical trials of cardiac resynchronization therapy (CRT) have enrolled a select group of patients, with few patients in subgroups such as right bundle-branch block (RBBB). Analysis of population-based outcomes provides a method to identify real-world predictors of CRT outcomes.

METHODS AND RESULTS

Medicare Implantable Cardioverter-Defibrillator Registry (2005 to 2006) data were merged with patient outcomes data. Cox proportional-hazards models assessed death and death/heart failure hospitalization outcomes in patients with CRT and an implantable cardioverter-defibrillator (CRT-D). The 14 946 registry patients with CRT-D (median follow-up, 40 months) had 1-year, 3-year, and overall mortality rates of 12%, 32%, and 37%, respectively. New York Heart Association class IV heart failure status (1-year hazard ratio [HR], 2.23; 3-year HR, 1.98; P<0.001) and age ≥ 80 years (1-year HR, 1.74; 3-year HR, 1.75; P<0.001) were associated with increased mortality both early and late after CRT-D. RBBB (1-year HR, 1.44; 3-year HR, 1.37; P<0.001) and ischemic cardiomyopathy (1-year HR, 1.39; 3-year HR, 1.44; P<0.001) were the next strongest adjusted predictors of both early and late mortality. RBBB and ischemic cardiomyopathy together had twice the adjusted hazard for death (HR, 1.99; P<0.001) as left BBB and nonischemic cardiomyopathy. QRS duration of at least 150 ms predicted more favorable outcomes in left BBB but had no impact in RBBB. A secondary analysis showed lower hazards for CRT-D compared with standard implantable cardioverter-defibrillators in left BBB compared with RBBB.

CONCLUSIONS

In Medicare patients, RBBB, ischemic cardiomyopathy, New York Heart Association class IV status, and advanced age were powerful adjusted predictors of poor outcome after CRT-D. Real-world mortality rates 3 to 4 years after CRT-D appear higher than previously recognized.

Implantable Cardioverter-Defibrillator Therapy for Primary Prevention of Sudden Cardiac Death: An Argument for Restraint

Although it is estimated that a total of 220,000 patients undergo implantable cardioverter-defibrillator (ICD) implantation per year, only 10% to 20% of these patients experience life-saving therapy; this leaves up to 90% of the targeted population as "nonresponders," who do not derive clinical benefit but incur all of the risks from ICD implantation. This article reviews the landmark primary prevention trials to assess the incidence of sudden death and the absolute magnitude of benefit derived from ICD therapy. The discrepancy between trial patients and real-world implementation of ICD therapy is examined, and the potential for risks incurred from ICD implantation is presented. The natural history of patients who receive appropriate ICD therapy and the durability of ICD benefit with respect to cost-effective analyses are discussed, to support the authors' position that ICD therapy should not be routinely used for the primary prevention of sudden cardiac death.