Health Technology Assessment (Nov 2013)
Clinical effectiveness and cost-effectiveness of second- and third-generation left ventricular assist devices as either bridge to transplant or alternative to transplant for adults eligible for heart transplantation: systematic review and cost-effectiveness model
Abstract
Background: Advanced heart failure (HF) is a debilitating condition for which heart transplant (HT) offers the best treatment option. However, the supply of donor hearts is diminishing and demand greatly exceeds supply. Ventricular assist devices (VADs) are surgically implanted pumps used as an alternative to transplant (ATT) or as a bridge to transplant (BTT) while a patient awaits a donor heart. Surgery and VADs are costly. For the NHS to allocate and deliver such services in a cost-effective way the relative costs and benefits of these alternative treatments need to be estimated. Objectives: To investigate for patients aged ≥ 16 years with advanced HF eligible for HT: (1) the clinical effectiveness and cost-effectiveness of second- and third-generation VADs used as BTT compared with medical management (MM); and (2) the clinical effectiveness and cost-effectiveness of second- and third-generation VADs used as an ATT in comparison with their use as BTT therapy. Data sources: Searches for clinical effectiveness studies covered years from 2003 to March 2012 and included the following data bases: MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations, EMBASE, Cochrane Database of Systematic Reviews (CDSR), Database of Abstracts of Reviews of Effects (DARE), NHS Economic Evaluation Database (NHS EED), HTA databases [NHS Centre for Reviews and Dissemination (CRD)], Science Citation Index and Conference Proceedings (Web of Science), UK Clinical Research Network (UKCRN) Portfolio Database, Cumulative Index to Nursing and Allied Health Literature (CINAHL), PsycINFO and National Library of Medicine (NLM) Gateway, Cochrane Central Register of Controlled Trials (CENTRAL), Current Controlled Trials and ClinicalTrials.gov. Reference lists of relevant articles were checked, and VAD manufacturers' websites interrogated. For economic analyses we made use of individual patient data (IPD) held in the UK Blood and Transplant Database (BTDB). Review methods: Systematic reviews of evidence on clinical effectiveness and cost-effectiveness of second- and third-generation US Food and Drug Administration (FDA) and/or Conformité Européenne (CE) approved VADs. Publications from the last 5 years with control groups, or case series with 50 or more patients were included. Outcomes included survival, functional capacity (e.g. change in New York Heart Association functional classification), quality of life (QoL) and adverse events. Data from the BTDB were obtained. A discrete-time, semi-Markov, multistate model was built. Deterministic and probabilistic methods with multiple sensitivity analyses varying survival, utilities and cost inputs to the model were used. Model outputs were incremental cost-effectiveness ratios (ICERs), cost/quality-adjusted life-years (QALYs) gained and cost/life-year gained (LYG). The discount rate was 3.5% and the time horizon varied over 3 years, 10 years and lifetime. Results: Forty publications reported clinical effectiveness of VADs and one study reported cost-effectiveness. We found no high-quality comparative empirical studies of VADs as BTT compared with MM or as ATT compared with BTT. Approximately 15–25% of the patients receiving a device had died by 12 months. Studies reported the following wide ranges for adverse events: 4–27% bleeding requiring transfusion; 1.5–40% stroke; 3.3–48% infection; 1–14% device failure; 3–30% HF; 11–32% reoperation; and 3–53% renal failure. QoL and functional status were reported as improved in studies of two devices [HeartMate II® (HMII; Thoratec Inc., Pleasanton, CA, USA) and HeartWare® (HW; HeartWare Inc., Framingham, MA, USA)]. At 3 years, 10 years and lifetime, the ICERs for VADs as BTT compared with MM were £122,730, £68,088 and £55,173 respectively. These values were stable to changes in survival of the MM group. Both QoL and costs were reduced by VADs as ATT compared with VADs as BTT giving ICERs in south-west quadrant of the cost effectiveness plain (cost saving/QALY sacrificed) of £353,467, £31,685 and £20,637 over the 3 years, 10 years and lifetime horizons respectively. Probabilistic analyses yielded similar results for both research questions. Limitations: Conclusions about the clinical effectiveness were limited by the lack of randomised controlled trials (RCTs) comparing the effectiveness of different VADs for BTT or comparing BTT with any alternative treatment and by the overlapping populations in published studies. Although IPD from the BTDB was used to estimate the cost-effectiveness of VADs compared with MM for BTT, the lack of randomisation of populations limited the interpretation of this analysis. Conclusions: At 3 years, 10 years and lifetime the ICERs for VADs as BTT compared with MM are higher than generally applied willingness-to-pay thresholds in the UK, but at a lifetime time horizon they approximate threshold values used in end of life assessments. VADs as ATT have a reduced cost but cause reduced QALYs relative to BTT. Future research should direct attention towards two areas. First, how any future evaluations of second- or third-generation VADs might be conducted. For ethical reasons a RCT offering equal probability of HT for each group would not be feasible; future studies should fully assess costs, long-term patient survival, QoL, functional ability and adverse events, so that these may be incorporated into economic evaluation agreement on outcomes measures across future studies. Second, continuation of accurate data collection in the UK database to encompass QoL data and comparative assessment of performance with other international centres. Funding: The National Institute for Health Research Health Technology Assessment programme.
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