European Heart Journal Advance Access originally published online on November 16, 2006
European Heart Journal 2007 28(1):42-51; doi:10.1093/eurheartj/ehl382
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The long-term cost-effectiveness of cardiac resynchronization therapy with or without an implantable cardioverter-defibrillator
1 Department of Primary Care and General Practice, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
2 Health Services Management Centre, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
3 Department of Cardiology, Hôpital Pontchaillou, Rennes, France
4 Department of Cardiology, University of Hull, Castle Hill Hospital, Kingston upon Hull, UK
Received 21 June 2006; revised 26 September 2006; accepted 26 October 2006; online publish-ahead-of-print 16 November 2006.
* Corresponding author. Tel: +44 121 414 7943; fax: +44 121 414 3353. E-mail address: n.freemantle{at}bham.ac.uk
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Abstract |
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Aims Cardiac resynchronization therapy (CRT-P) is an effective treatment for patients with heart failure and cardiac dyssynchrony with moderate or severe symptoms despite pharmacological therapy. The addition of an implantable cardioverter-defibrillator (ICD) function may further reduce the risk of sudden death. We assessed the cost-effectiveness of CRT-P compared with medical therapy (MT) alone, and the cost-effectiveness of CRT–ICD + MT compared with CRT-P + MT, on incremental cost per quality adjusted life year (QALY) and life year using data from two landmark clinical trials.
Methods and results A Markov model with Monte Carlo simulation to assess costs, life years, and QALYs associated with CRT (± ICD) and MT in patients with heart failure and cardiac dyssynchrony, on the basis of a UK healthcare perspective was constructed. NYHA class distribution and transitions, associated health utilities, rates and cause of hospitalization and death were estimated from individual patient data from the CArdiac REsychronization in Heart Failure (CARE-HF trial). The estimated additional benefit on survival of an ICD was based on results from COMPANION. The base case analysis used 10 000 individual life-time simulations assuming a battery life of 6 years for CRT-P and 7 years for CRT–ICD. From a life-time perspective in a 65-year-old patient, the incremental cost-effectiveness of CRT-P compared with MT is 
7538 (95% CI 5325–11 784) per QALY gained and 7011 (95% CI 5346–10 003) per life year gained. The incremental cost-effectiveness of CRT–ICD compared with CRT-P is 47 909 (95% CI 35 703–79 438) per QALY gained, and 35 864 (95% CI 26 709–56 353) per life year gained.
Conclusion Long-term treatment with CRT-P appears cost-effective compared with MT alone. From a life-time perspective, assuming a reasonable life expectancy when receiving effective treatment for heart failure, CRT–ICD may also be considered cost-effective when compared with CRT-P + MT.
Key Words: Cost effectiveness • Cardiac resynchronization therapy • Implantable cardioverter defibrillator • Markov model • Individual simulation
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Introduction |
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Heart failure is a common disease and costly in terms of morbidity, mortality, and resources consumed.1–3
Randomized controlled trials have demonstrated that cardiac resynchronization therapy (CRT-P) and cardiac resynchronization with an implantable cardioverter-defibrillator (CRT–ICD) improve symptoms, exercise capacity, ventricular function, quality-of-life, and reduces mortality in patients with heart failure due to cardiac dyssynchrony who have persistent moderate or severe symptoms, despite standard pharmacological therapy.4–8
A within-trial cost-effectiveness analysis based on individual patient data from the CARE-HF trial and UK cost structures showed that CRT-P was associated with increased costs (4316, 95% CI: 1327–7485), increased survival (0.10 years, 95% CI – 0.01–0.21), and increased quality adjusted life years (QALYs) (0.22 95% CI 0.13–0.32).9 The incremental cost-effectiveness ratio (ICER) was 19 319 per QALY gained (95% CI: 5482–45 402) and 43 596 per life-year gained (95% CI: – 146 236–223 849). The results were sensitive to the costs of device and procedure, and indicate that treatment with CRT-P is cost-effective at the notional willingness to pay threshold of 29 400 (£20 000) per QALY gained. The within-trial analysis suggests that CRT-P might be cost-effective over a patients lifetime, but this has not been established with trial evidence.
Previous evaluations have provided varying estimates of the cost-effectiveness of CRT-P and CRT–ICD relative to medical therapy (MT).10–12 However, none has addressed the incremental cost-effectiveness of CRT-P vs. CRT–ICD, a more relevant and appropriate question, and none has been completed since the availability of the results from the CARE-HF trial.7 It is quite possible that CRT–ICD may appear cost-effective compared with MT, but the incremental benefit of ICD in addition to CRT-P might be beyond the threshold of willingness to pay (UK perspective). This could occur if the additional costs associated with the ICD component are high compared with any additional benefits gained.
We developed an economic model populated with data from CARE-HF7 to evaluate the long-term incremental cost-effectiveness of CRT-P and MT compared with MT alone, on incremental cost per QALY and life-year gained. In addition, we evaluated the cost-effectiveness of CRT–ICD + MT vs. MT and the relative cost-effectiveness of CRT-P and CRT–ICD, incorporating estimates of the proportion of sudden deaths that might be prevented with CRT–ICD from the COMPANION study.13 The incremental cost-effectiveness of CRT-P or CRT–ICD in different patient subgroups was also evaluated.
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Methods |
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Overview of CARE-HF
The design and results of the CARE-HF study have been reported previously.7 In brief, eligible patients were at least 18 years of age, had evidence of heart failure for at least 6 weeks, and were in New York Heart Association (NYHA) class III or IV despite receipt of standard pharmacological therapy, with a left ventricular ejection fraction of < 35%, a left ventricular end-diastolic dimension of
30 mm (indexed to height), and a QRS interval of > 120 ms on the electrocardiogram. Patients with a QRS interval of 120–149 ms were required to meet two of three additional criteria for dyssynchrony: an aortic pre-ejection delay of more than 140 ms, an interventricular mechanical delay of more than 40 ms, or delayed activation of the posterolateral left ventricular wall. A total of 813 patients were randomly assigned to receive MT alone (n = 404) or with cardiac resynchronization (n = 409).
Model structure
We constructed a Markov model with Monte Carlo simulation to describe the clinical history of patients with NYHA class III/IV treated with CRT-P plus MT compared with MT alone, CRT–ICD + MT compared with MT alone, and CRT–ICD plus MT compared with CRT-P plus MT. Health states were defined by NYHA functional class and death. Mortality was sub-classified by cause including: death due to worsening heart failure; sudden death; death due to all other causes. As simulated patients pass through the model, cost, and QALYs associated with each state, their experiences are accumulated.
The initial distribution of the NYHA classes, age, and gender, and subsequent transition probabilities and costs associated with treatment by MT or CRT-P + MT were based on the intention-to-treat analysis of the CARE-HF trial.7
The additional effect of ICD on sudden death was based on the observed and projected rate in patients assigned to CRT-P in CARE-HF and the proportional reduction in sudden death observed in COMPANION in patients assigned to CRT–ICD compared with CRT-P.13 Mortality for other causes was derived from the UK population.14
Model description
The model had two components: the short-term representing changes in health status and the costs and consequences of the process of device implantation, and the long-term effects of the device after successful implantation (Figures 1 and 2). In the model, MT patients did not receive CRT-P or CRT–ICD during follow-up. The CRT-P and CRT–ICD groups received treatment with their assigned therapy in accordance with the successful device implantation rates observed in the CARE-HF trial.7 In the long-term phase, patients faced different risks of sudden death and unplanned hospitalization depending on their health state, treatment group, and duration of treatment. During each cycle of the model, patients could move between the four NYHA health states, experience sudden death, or have an unplanned hospitalization for a major cardiac event. We assumed that transition probabilities between NYHA classes only differed by CRT and were independent of the time in that health state, based on data from CARE-HF.7 Patients faced treatment and time-dependent risks for experiencing sudden death and unplanned hospitalization. Unplanned hospitalizations were categorized by type: procedure-related; non-procedure-related; and those leading to death due to worsening heart failure.
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Input data
Estimates of the rate of successful implantation
Table 1 shows the rates of successful device implantation derived from total implantation experience (in both the CRT-P and MT groups) in the CARE-HF trial.7
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Efficacy
Effectiveness is expressed as transition probabilities between Markov states. The transition probabilities among NYHA classes differed in the short- and long-run. In the short-run, we assumed there was an immediate response to treatments at the end of the first month.
Table 1 shows the estimated transition probabilities among NYHA classes based on available data derived from 388 (94.1%) and 380 (94.9%) patients in the CARE-HF CRT-P and MT groups, respectively.
The long-term treatment effect on NYHA class was assumed to follow constant transition probabilities. This is supported by the CARE-HF trial data.7 In the CARE-HF trial, outcomes including NYHA class have been measured at months 1, 6, 9, and 12, and every 6 months thereafter. The monthly transition probabilities from one NYHA class to another for the long-term were derived from NYHA classes assessed at month 1 and 6. We estimated monthly transition probability on the basis of the 5 month data by matrix algebra on the assumption of a constant Markov chain property during this period (Table 1). Each NYHA class was assigned a utility score independent of treatment which was estimated from quality-of-life assessments made during CARE-HF using the EQ-5D at baseline and 90 days (Table 2). Utility weights were combined with life-years to estimate QALYs.
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Estimating time to sudden death
Estimates of the time to sudden death were based on the Kaplan–Meier survival curve extrapolated using a Weibull distribution from the CARE-HF trial (Table 3).7
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Estimating time to unplanned hospitalization
The baseline survival function for time to cardiovascular unplanned hospitalization was derived from the time to first unplanned hospitalization using a Weibull survival function. Table 3 shows the estimated hazards ratios by different NYHA class with NYHA class I as reference case.
Estimating the risk reduction from ICD
The estimated additional benefit of ICD in reducing sudden death was based on the observed rate of sudden death in patients assigned to CRT-P in CARE-HF and the difference in sudden death rates in the COMPANION trial between the CRT-P and CRT–ICD groups, based on a median follow-up in that trial of 16 months in the device therapy groups.6,13 We assumed no additional benefit apart from preventing sudden death attributable to ICD. The monthly probability of hospitalization has been reported to be similar for CRT-P and CRT–ICD in the COMPANION trial12 (0.098 and 0.097 respectively), so no further penalty was applied to CRT–ICD patients for hospitalization rates due to the presence of the ICD component.
Cost analysis
The economic analysis was conducted from a UK NHS perspective, including device cost of CRT-P and CRT–ICD, implantation procedure cost, cost of hospitalization (hospital stay during implantation and unplanned hospitalization), medical care cost, and drug costs, and were converted to euros based on a conversion rate of 1.47 = £1. Implantation cost included device cost, procedure cost, intravenous medication, and hospital stay (including ICU and CCU). Table 2 summarizes the cost data by different categories.
Medical care cost included outpatient visits, cardiology or primary care visits, and length of time spent in nursing or residential homes or rehabilitation centres. Cost per patient per day for medical care and drug cost were estimated from CARE-HF.7 We assumed the same drug and medical care costs per day for all treatment groups.
Unplanned hospitalization for a major cardiac event was characterized by the presence or absence of a procedure cost. Procedure costs included ICU, CCU, CABG, PTCA, and heart transplantation. Procedure costs were based on the frequency and cost of events, and average costs for ICU and CCU. The unit costs employed have been previously reported.9
Battery life
On the basis of product specifications, we assumed that batteries were replaced for surviving patients in the CRT-P group every 6 years, and every 7 years in the CRT–ICD group.15,16 In order to examine the influence of battery life on the cost-effectiveness of the CRT–ICD device, which will vary with the device used and the specific programming employed, we also examined the cost-effectiveness of CRT–ICD using a device life of 4, 5, 6, and 8 years. The cost associated with battery replacement was the device cost plus one cardiac out-patient visit day.
Patient age
While the base case assumed a starting age of 65, this was varied in sensitivity analyses to examine the extent to which patient starting age (and thus life expectancy) affected the results of the model.
Discounting
We adopted a discount rate of 3.5% annually for costs and benefits.
Probabilistic sensitivity analysis
We conducted probabilistic sensitivity analysis across all input values, together with scenario analysis of the assumptions within the model. Tables 1–3 list all input values and their respective distributions used to examine second-order uncertainty.17 Each set of random input values was drawn on the bass of their specific distributions for every 10 000 patients and the results were iterated 1000 times. We constructed cost-effectiveness acceptability curves to illustrate uncertainty.
Model validation
We validated the model using the observed results of CARE-HF and the published results from COMPANION.9,13
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Results |
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Survival
For the base-case analysis, where all mean input values were used based on 10 000 individual simulations, and patients started at a fixed age of 65, the predicted median survival was 7.44, 10.53, and 11.98 years for MT, CRT-P and CRT–ICD, respectively and 75% of patients were dead by 11.33, 15.92, and 17.92 years (Table 4, Figure 3). The undiscounted life gained for CRT-P vs. MT was 3.09 years and for CRT–ICD vs. CRT-P was 1.45 years.
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Cost-effectiveness results
Tables 5–7 show the difference in costs, life years, and QALYs by group for the base case. The total cost per patient for CRT–ICD + MT was
87 350 compared with 53 996 and 39 060 for CRT-P + MT and MT, respectively. The mean life-time QALYs were 6.75, 6.06, and 4.08 and life years was 9.16, 8.23, and 6.10 for CRT–ICD + MT, CRT-P + MT, and MT, respectively.
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For the comparison of CRT-P + MT and MT, the probabilistic sensitivity analysis gave an incremental cost of
14 935, a QALY score of 1.98, and a life-year estimate of 2.13. This gives ICERs of 7,538 (95% CI 5325–11 784) per QALY gained and 7011 (95% CI 5346–10 003) per life-year gained. The incremental cost-effectiveness of CRT–ICD + MT vs. MT is 18 017 (95% CI 14 500–25 070) per QALY gained, and 15 780 (95% CI 12 955–20 728) per life-year gained. For CRT–ICD + MT vs. CRT-P + MT, the incremental cost is 33 354, the QALY score is 0.70, and the life years gained is 0.93. The ICER here is 47 909 (95% CI 35 703–79 438) per QALY gained, and 35 864 (95% CI 26 709–56 353) per life year gained.
Figures 4A and B present the cost-effectiveness acceptability curves for CRT-P + MT and CRT–ICD + MT vs. MT, and CRT–ICD + MT vs. CRT-P + MT respectively. On the basis of a willingness to pay threshold of 44 100 (£30 000)/QALY, CRT–ICD + MT has a probability of 0.40 of being cost-effective compared with CRT-P + MT treatment alone.18
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Analyses by cohort age
We modelled patient groups who started at age 55, 60, 70, and 75 (Table 8, Figure 5). If patients received CRT–ICD at age 60, the ICER for the comparison with CRT-P alone decreased from
47 909–42 701 per QALY gained, and for patients starting at age 55, the ICER fell to 36 777. Similarly, for patients starting at age 75, the ICER rose to 73 299.
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Length of follow-up
The effect of varying the period of follow-up in the model is shown in Table 9.
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Battery life
The effect of different battery life for CRT–ICD on the incremental cost per QALY is described in Table 10. Reducing battery life to 4 years, the cost per QALY for CRT–ICD + MT vs. CRT-P + MT was increased to
75 091. Conversely, increasing battery life to 8 years reduced the cost per QALY for this comparison to 43 506.
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Model validity
In Table 9, we assessed the internal validity of the model output by estimating a variety of shorter-term effects to contrast with other models12 and with the within-trial analysis from CARE-HF trial.9 Figure 6 contrasts the model predicted and observed survival in the CARE-HF trial.
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Discussion |
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For the base case, CRT-P appears a highly cost-effective addition to MT among eligible patients. CRT–ICD + MT also appears cost-effective compared with MT, although this may not be considered an appropriate comparison as the treatment with high cost relative to benefits may appear cost-effective when combined with a highly cost-effective regimen. However, from a life-time perspective, assuming a reasonable life expectancy when receiving effective treatment for heart failure, CRT–ICD + MT may still appear cost-effective, although to a lesser extent, compared with CRT-P + MT.18 CRT-P + MT appeared cost-effective in all age groups. The cost-effectiveness of CRT-P + MT for patients in the ninth decade of life may seem surprising. This gain reflects a substantial benefit on quality-of-life among survivors, and some increase in longevity. The cost-effectiveness of CRT–ICD + MT is substantially greater in younger subjects, due to the longer potential period when the subject is at risk of sudden death. The cost-effectiveness of CRT–ICD + MT compared with CRT-P + MT was lower in older people partly because these treatments exert similar effects on quality-of-life and because older patients were likely to die of other problems even if sudden death was treated. Varying the period of follow-up in the model (Table 9) indicates the sensitivity of the results for CRT–ICD + MT to the duration of follow-up being considered, effectively the duration of the patients' exposure to the risk of sudden death. It also indicates the similarity of the model results to our previously reported within-trial analysis.9
Sensitivity analyses varying the length of CRT–ICD battery life significantly affects the cost-effectiveness of CRT–ICD + MT compared with CRT-P + MT. Our base-case analysis considered a battery life of 6 years for CRT-P and 7 years for CRT–ICD based on information from the manufacturer. Estimates of device longevity for older generation CRT–ICD products were 5–6 years, however, current developments in lead technology mean that lower battery consumption is needed to stimulate effectively the chamber with an appropriate safety margin. However, the device longevity for the CRT–ICD device also assumed an energy conserving programming specification, which may not be used routinely in practice, and the device longevity we assumed in the base case may not be achieved in practice.19,20 Longer battery life clearly results in an increased cost-effectiveness of CRT–ICD + MT compared with CRT-P + MT, but conversely shorter device life in practice will result in reduced cost-effectiveness. Further improvements in device technology, including the duration of battery life, present an important future challenge to the device manufacturers.
This model-derived analysis extends our previously published within-trial analysis based upon 29.4 months of mean follow-up.9 It also further advances the work described in the COMPANION cost-effectiveness analysis which provided estimates of benefit at 7 years which are similar to those observed in our model at 6 years. In addition, our work examines the ICER associated with adding an ICD component to CRT therapy.
Our analysis has a number of strengths. The existing clinical trials provide considerable evidence for the long-term effectiveness of both CRT-P and CRT–ICD, but most patients were alive and many felt well at the end of the trials. Patients' treatment does not cease at the end of the trial and it is inappropriate to assume that benefits cease at that point. In taking a life-time approach, we have been able to consider important issues such as device replacement, which none of the existing trials has had long enough follow-up to address. Economic modelling also enables the inclusion of data and other evidence from a range of sources in order to examine health policy questions.
The question of whether to implant CRT-P or CRT–ICD remains controversial, and as Jarcho21 has noted, a definitive trial comparing these treatments may never be conducted. In the absence of evidence from a definitive trial comparing CRT-P and CRT–ICD, economic modelling provides one useful perspective to health policy decisions.22 Our analysis indicates that CRT–ICD is cost-effective compared with CRT-P for patients with a reasonable life expectancy (when treated). However, the cost-effectiveness of CRT–ICD is sensitive to the frequency and cost of device replacements. Reduced device cost and increased device longevity both increase the cost-effectiveness of CRT–ICD.
There are a number of limitations to our analysis. The analysis is based on simulation rather than the direct observation of event rates achieved in a randomized trial, although simulation that has been constructed from a large scale long-term trial and in which the additional benefits of CRT–ICD are addressed using individual patient data from the CARE-HF trial to identify potentially preventable sudden deaths, and a further randomized trial of the effects of ICD on sudden death (COMPANION13). Thus our work may be considered a best-evidence synthesis of the likely cost-effectiveness of CRT-P and CRT–ICD, although the strength of that evidence is not as high as direct observation from sufficiently powered and appropriately designed randomized trials.
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Conclusions |
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Long-term treatment with CRT-P + MT appears cost-effective compared with MT alone. CRT–ICD + MT was also cost-effective, although to a lesser extent, compared with CRT-P + MT at a willingness to pay of
44 100 (£30 000) per QALY, in the treatment of patients with moderate-to-severe heart failure characterized by dyssynchrony, except in those who have a poor life expectancy.
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Acknowledgements |
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This study was funded by an unrestricted research grant from Medtronic Inc. N.F., J.G.F.C., and J.C.D. have received funding for research, consultancy, and travel from companies that manufacture devices for the treatment of heart failure and other related conditions. M.J.C. has received salary support from grants funded by Medtronic Inc.
Conflict of interest: Medtronic Inc., who funded this study, had the option to comment upon the final draft of the manuscript. The funders had no involvement in the design or analysis of the study, or in the drafting of the paper other than providing comments as above. The authors were not obliged to incorporate comments received from the sponsor. G.L.Y. and S.B. have no conflicts of interest.
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References |
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TopAbstractIntroductionMethodsResultsDiscussionConclusionsAcknowledgementsReferences |
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- http://www.escardio.org/knowledge/ehs/survey/Heart_Failure_II.htm(21 November 2005).
- Stewart S. (2005) Financial aspects of heart failure programs of care. Eur J Heart Fail 7:423–428.[CrossRef][ISI][Medline]
- Cazeau S, Leclercq C, Lavergne T, Walker S, Varma C, Linde C, Garrigue S, Kappenberger L, Haywood GA, Santini M, Bailleul C, Daubert JC. (2001) Effects of multisite biventricular pacing in patients with heart failure and intraventricular conduction delay. N Engl J Med 344:873–880.
[Abstract/Free Full Text] - Young JB, Abraham WT, Smith AL, Leon AR, Lieberman R, Wilkoff B, Canby RC, Schroeder JS, Liem LB, Hall S, Wheelan K. (2003) Combined cardiac resynchronization and implantable cardioversion defibrillation in advanced chronic heart failure: the MIRACLE ICD Trial. JAMA 289:2685–2694.
[Abstract/Free Full Text] - Abraham WT, Fisher WG, Smith AL, Delurgio DB, Leon AR, Loh E, Kocovic DZ, Packer M, Clavell AL, Hayes DL, Ellestad M, Trupp RJ, Underwood J, Pickering F, Truex C, McAtee P, Messenger J. (2002) Cardiac resynchronization in chronic heart failure. N Engl J Med 346:1845–1853.
[Abstract/Free Full Text] - Bristow MR, Saxon LA, Boehmer J, Krueger S, Kass DAMD, De Marco T, Carson P, DiCarlo L, DeMets D, White BG, DeVries DW, Feldman AM. (2004) Cardiac-resynchronization therapy with or without an implantable defibrillator in advanced chronic heart failure. N Engl J Med 350:2140–2150.
[Abstract/Free Full Text] - Cleland JGF, Daubert JC, Erdmann E, Freemantle N, Gras D, Kappenberger L, Tavazzi L. (2005) The effect of cardiac resynchronization on morbidity and mortality in heart failure. N Engl J Med 352:1539–1549.
[Abstract/Free Full Text] - Freemantle N, Tharmanathan P, Calvert M, Abraham WT, Ghosh J, Cleland JGF. (2006) Cardiac resynchronization for patients with heart failure due to left ventricular systolic dysfunction: a systematic review and meta-analysis accepted for publication. Eur J Heart Fail 8:433–440.[CrossRef][ISI][Medline]
- Calvert MJ, Freemantle N, Yao G, Cleland JGF, Billingham L, Daubert JC, Bryan S. (2005) Cost-effectiveness of cardiac resynchronization therapy: results from the CARE-HF trial. Eur Heart J Published online ahead of print November 11, 2005.
- Nichol G, Kaul P, Huszti E, Bridges JFP. (2004) Cost-effectiveness of cardiac resynchronization therapy in patients with symptomatic heart failure. Ann Intern Med 141:343–351.
[Abstract/Free Full Text] - Banz K. (2005) Cardiac resynchronization therapy (CRT) in heart failure: a model to assess the economic value of this new medical technology. Value Health 8:128–139.[CrossRef][ISI][Medline]
- Feldman AM, de Lissovoy G, Bristow MR, Saxon LA, de Marco T, Kass DA, Boehmer J, Singh S, Whellan DJ, Carson P, Boxcoe A, Baker TM, Gunderman MR. (2005) Cost effectiveness of cardiac resynchronization therapy in the comparison of medical therapy, pacing and defibrillation in heart failure (COMPANION) trial. J Am Coll Cardiol 46:2311–2321.
[Abstract/Free Full Text] - Carson P, Anand I, O'Connor C, Jaski B, Steinberg J, Lwin A, Lindenfeld J, Ghali J, Barnet JH, Feldman AM, Bristow MR. (2005) Mode of death in advanced heart failure. The Comparison of Medical, Pacing, and Defibrillation Therapies in Heart Failure (COMPANION) Trial. JACC 46:2329–2334.
[Abstract/Free Full Text] - http://www.gad.gov.uk/Life_Tables/Interim_Life_Tables.htm (9 January 2006).
- http://manuals.medtronic.com/OrderManagementCONCERTOC174AWKReferenceManual (28 August 2006).
- Medtronic Inc. (2001) Insync III 8042 Implant Manual.
- Briggs AH. (2000) Handling uncertainty in cost-effectiveness models. Pharmacoeconomics 17:479–500.[CrossRef][ISI][Medline]
- Rawlins MD and Culyer AJ. (2004) National institute for clinical excellence and its value judgments. BMJ 329:224–227.
[Free Full Text] - Gould PA and Krahn AD. (2006) Complications associated with implantable cardioverter-defibrillator replacement in response to device advisories. JAMA 295:1907–1911.
[Abstract/Free Full Text] - Maisel WH, Moynahan M, Zuckerman BD, Gross TP, Tovar OH, Tillman DB, Schultz DB. (2006) Pacemaker and ICD generator malfunctions: analysis of the Food and Drug Administration Annual Reports. JAMA 295:1901–1906.
[Abstract/Free Full Text] - Jarcho JA. (2005) Resynchronizing ventricular contraction in heart failure. New Engl J Med 352:1594–1597.
[Free Full Text] - Salkeld G, Freemantle N, O'Brien B. (2004) Economic modelling in drug reimbursement. In Freemantle N and Hill S (Eds.). Evaluating Pharmaceuticals for Health Policy and Reimbursement(Blackwell Publishing Ltd, Oxford).
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 F. A. McAlister, J. Ezekowitz, N. Hooton, B. Vandermeer, C. Spooner, D. M. Dryden, R. L. Page, M. A. Hlatky, and B. H. Rowe Cardiac Resynchronization Therapy for Patients With Left Ventricular Systolic Dysfunction: A Systematic Review JAMA, June 13, 2007; 297(22): 2502 - 2514. [Abstract] [Full Text] [PDF]
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