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Economics of carotid revascularization

Stroke has enormous direct cost for the healthcare system and the society; in addition, it reduces quality of life and functional capacity. Therefore, the incorporation of economic analysis to clinical trials assessing different methods aiming to improve stroke-related outcomes appears very appropriate. The present study includes 310 patients randomized to each treatment arm and followed for one year. The author’s extrapolated one year data to cost per life year saved done using regression and imputation analysis [1]. They reported on the economic outcomes of patients randomized to either a carotid stent implantation or carotid endarterectomy surgery as part of a previously published trial [2] of high risk patients, which can be identified based on clinical or anatomic criteria [3]. The authors report that stent patients had higher initial procedure costs that were nearly offset by shorter length of stay in this group versus endarterectomy surgery. Neither follow-up costs after discharge nor total one-year costs differed significantly. Stroke or myocardial infarction (MI) may not be the only reason for prolonged length of stay; cranial nerve palsy after surgical exploration as well as persistent hypotension due to baroreceptor stimulation [4] may occur after any type of procedure [5]. As patients randomly assigned to carotid stent had better clinical outcomes at one-year, the authors projected that this approach would improve life expectancy by 0.51 quality-adjusted-life-years (QALYs) compared to surgery. Ultimately, the authors project a lifetime costeffectiveness ratio of $6,555/QALY for patients undergoing stent compared with endarterectomy. The results appear more favorable for the stent approach within the symptomatic patient subgroup, while the difference is narrower (still concordant) in asymptomatic patients. First, the study raises some important questions on extrapolation of the one year data; there is no clear description of the method used to project lifetime costs. Projections of life expectancy are central to the lifetime cost-effectiveness estimate. The authors analyzed data from a Canadian Health System Database for this purpose. These life expectancy estimates were based on data from 31,006 patients hospitalized between 1990 and 1995 with a history of stroke or peripheral arterial disease in Saskatchewan. With respect to the United States, a different standard of care may exist, including variability in intensity of secondary prevention as well as in the way outcome measures are defined. For instance, the authors estimate nonfatal MI reduces life expectancy by 4.37 to 5.12 years, whereas shorter estimates have been proposed from other databases. The Saskatchewan Health database had a limited number of patients who experienced both a major stroke and an MI, and patients who experienced both events during the trial were assigned the shorter of the two life expectancies. One must question the appropriateness of assigning the lesser of the two life expectancies, the effect on the unaccounted outcome for the patient. Regardless of the limitations included in the article itself, the present study is an ambitious attempt to initiate a cost effectiveness discussion in relation to a complex medical decision on treatment strategy selection. In general, a cost-effectiveness analysis is mainly driven by mortality differences. Carotid trials have produced no result to this end thus far. Next, the cost and quality of life implications of the secondary endpoints are considered. These include stroke and MI, albeit not in a strict hierarchy. In addition, other adverse events such as cranial nerve palsy, wound infections, or even rare contrast media reactions [6], should also be considered in a dedicated quality of life and costeffectiveness analysis. These clinical problems inherently limit any economic analysis. On the other hand, the fact that repeat procedures are very rare after either type of carotid revascularization after long-term follow-up [7] facilitates an economic analysis since this would be mainly driven by the in-hospital and 30-day events. Factors that should be considered for more complete event evaluation with respect to future quality of life and cost-effectiveness assessment include: (a) how disabling was the stroke, (b) how large was the MI, (c) in