Objective: Carotid angioplasty and stenting (CAS) has been advocated as a minimally invasive and inexpensive alternative to carotid endarterectomy (CEA). However, a precise comparative analysis of the immediate and long-term costs associated with these two procedures has not been performed. To accomplish this, a Markov decision analysis model was created to evaluate the relative cost effectiveness of these two interventions.
Methods: Procedural morbidity/mortality rate for CEA and costs (not charges) were derived from a retrospective review of consecutive patients treated at New York Presbyterian Hospital/Cornell (n = 447). Data for CAS were obtained from the literature. We incorporated into this model both the immediate procedural costs and the long-term cost of morbidities, such as stroke (major stroke in the first year = $52,019; in subsequent years = $27,336/y; minor stroke = $9419). We determined long-term survival rate in quality-adjusted life years and lifetime costs for a hypothetic cohort of 70-year-old patients undergoing either CEA or CAS. Our measure of outcome was the cost-effectiveness ratio.
Results: The immediate procedural costs of CEA and CAS were $7871 and $10,133 respectively. We assumed major plus minor stroke rates for CEA and CAS of 0.9% and 5%, respectively. We assumed a 30-day mortality rate of 0% for CEA and 1.2% for CAS. In our base case analysis, CEA was cost saving (lifetime savings = $7017/patient; increase in quality-adjusted life years saved = 0.16). Sensitivity analysis revealed major stroke and death rates as the major contributors to this differential in cost effectiveness. Procedural costs were less important, and minor stroke rates were least important. CAS became cost effective only if its major stroke and mortality rates were made equivalent to those of CEA.
Conclusion: CEA is cost saving compared with CAS. This is related to the higher rate of stroke with CAS and the high cost of stents and protection devices. To be economically competitive, the mortality and major stroke rates of CAS must be at least equivalent if not less than those of CEA.