A Cost-Utility Analysis Of Transcatheter Versus Surgical Aortic Valve Replacement For The Treatment Of Aortic Stenosis In The Intermediate Surgical Risk Population
Derrick Y Tam1, Avery Hughes2, Saerom Youn2, Rebecca L Howard-Hancock2, Peter C Coyte2, Stephen E Fremes1, Harindra Wijeysundera3
1Division of Cardiac Surgery, Sunnybrook Health Sciences Centre, Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, ON, Canada2Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, ON, Canada3Division of Cardiology, Sunnybrook Health Sciences Centre, Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, ON, Canada
Objectives: Recent evidence suggests that transcatheter aortic valve implantation (TAVI) is non-inferior to surgical aortic valve replacement (SAVR) for early (30 days) and long term (2 years) mortality outcomes in patients with severe symptomatic aortic stenosis (AS), who are at an intermediate surgical risk. Our objective was to determine the cost-effectiveness of TAVI versus SAVR in the intermediate risk population.
Methods: A fully probabilistic Markov model with 30 day cycles was constructed from the Canadian third party payer's perspective to estimate the difference in cost and effectiveness (measured as Quality-Adjusted Life Years, QALYs) of TAVI versus SAVR for the intermediate risk patient population over a lifetime time horizon (Figure 1). Clinical trial data from the Placement of Aortic Transcatheter Valves 2 Trial (PARTNER 2), comparing a second generation balloon-expandable heart valve system (Edwards Lifesciences Sapien XT) to SAVR, was used to inform the efficacy inputs. Data from the Canadian Institute of Health Information Patient Cost-Estimator and the Ontario Schedule of Benefits were obtained for cost inputs. Incremental Cost-Effectiveness Ratios (ICERs) were calculated. All costs and utilities were discounted at 5% per annum. One-way sensitivity analyses and a Monte Carlo probabilistic sensitivity analysis (PSA) were conducted. All costs are presented in 2016 Canadian dollars (CAN). $1.00 CAN = $0.76 United States Dollar (Bank of Canada Currency Exchange Rate - January 7, 2017).
Results: In the base case analysis, the total life-time costs in present values for the TAVI and SAVR arms were $46,743±4,075 and $36,838±7,321 respectively while the QALYs gained were 4.63±1.17 and 4.43±1.17 for TAVI and SAVR respectively. Thus, the incremental cost of TAVI was $9,906 and the incremental gain in QALYs was 0.19. This resulted in an ICER of $51,288/QALY. Deterministic one-way analyses showed that the ICER was sensitive to rates of complications, cost of the TAVI valve and hospital lengths of stay. The PSA indicated moderate uncertainty in that TAVR was the preferred option in only approximately 52% (Figure 2) and 56% of the simulations at a $50,000 and $100,000 per QALY willingness-to-pay threshold (Figure 3), respectively. The driver of the uncertainty appeared to be in efficacy, reflecting the non-inferiority nature of the input data.
Conclusions: This study represents the first formal cost-effectiveness analysis comparing TAVI versus SAVR in the intermediate surgical risk population. TAVI was found to be a cost-effective option for the treatment of severe AS in intermediate surgical risk patients.
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