By Ruben Osnabrugge
For decades, surgical aortic valve replacement has been the standard of care for patients with symptomatic aortic stenosis, but in the last 10 years, transcatheter aortic valve implantation (TAVI) has emerged as a new treatment option. More than 50,000 valves have been implanted and in the PARTNER trial, TAVI has been shown to reduce two-year mortality by 25% as compared to medical treatment in patients not eligible for surgery. Moreover, it is non-inferior to surgery in terms of two-year survival for patients at high surgical risk.
With healthcare expenditures outpacing the growth of Western economies, health technology assessment is increasingly important. TAVI is a new technology that is both expensive and especially useful in treating elderly patients. Since ageing and costly new technologies are the main drivers of healthcare expenditures, an economic analysis of TAVI is inevitable.
At the Erasmus University Medical Center, Rotterdam, The Netherlands, a cost-analysis of 84 propensity matched surgical and transcatheter patients was performed (Osnabrugge RL, Head SJ, Genders TS et al. Ann Thorac Surg 2012; in press). The matched patients had an intermediate surgical risk (logistic EuroSCORE=13), which is a lower risk than in the PARTNER trial.
All in-hospital diagnostic, procedural and post-procedural resources, such as the transcatheter heart valve prosthesis (CoreValve / Medtronic), hospital stay, medications and blood products were collected. In addition the costs of transferring to general hospitals and of one year follow-up were calculated.
In the matched patient cohort, the total length of stay after TAVI was on average seven days shorter than after surgical replacement. Intensive care unit stay was roughly three days shorter, and ward stay four days shorter. Follow-up costs were similar between the treatments. The higher price of the valve and the involvement of more personnel and equipment in TAVI were not outweighed by lower expenditure on blood products and hospitalisation. Consequently, TAVI was more expensive at one year (roughly €45,000 vs. 35,000 for TAVI and surgical replacement, respectively, p=0.009).
The economic outcomes of the PARTNER trial reported similar costs for surgical and transcatheter replacement at one year (US$94,206 vs. US$96,417, respectively). Differences with the study from Rotterdam might be attributed to higher costs of hospital stay in the United States, a more eminent cost component in surgery than in TAVI.
Some crude statements on the cost-effectiveness of TAVI can be made. The PARTNER trial showed a quality-of-life gain of 0.068 at one year for TAVI compared to surgical replacement. Combining the cost results from our cost analysis with this quality of life gain in high-risk patients yields an incremental cost-effectiveness ratio (ICER) of around €150,000 per quality-adjusted life year saved, a figure which in general is considered higher than the threshold willingness-to-pay. Although ICERs should be calculated using life-time costs, follow-up costs in both the Rotterdam study and the PARTNER trial were similar for the two treatments and show that periprocedural costs will be the driver of cost-effectiveness of TAVI.
Certainly, more elaborate analyses are needed to confirm these cost-effectiveness results. With valves from other companies entering the market it will be interesting to see whether market forces will decrease the price of transcatheter valves, a trend previously observed in coronary stents. Also, the quality-of-life gain after TAVI in lower risk populations will play an important role in future economic analyses.
Ruben Osnabrugge is with the Department of Cardio-Thoracic Surgery, Erasmus Medical Center, Rotterdam, The Netherlands