Cost-Effectiveness of TAVI VS Minimally Invasive SAVR for Low-Risk Aortic Stenosis in Japan

Figures

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  Figure 1. Model Structure for the Cost-Effectiveness Analysis (A) Decision tree representing the acute (periprocedural) phase for TAVI and MICS-AVR. (B) Markov model illustrating transitions between postprocedural health states over time, including “alive and well,” post-PMI, poststroke, HF, SVD, and death. HF = heart failure; MICS-AVR = minimally invasive surgical aortic valve replacement; SVD = structural valve deterioration; TAVI = transcatheter aortic valve implantation.

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  Figure 2. Temporal Trends in Cost-Effectiveness Outcomes Over a 10-Year Horizon (A) Cumulative total costs, (B) total QALYs, and (C) trajectories of the ICER for TAVI and MICS-AVR. The ICER for TAVI decreased from approximately ¥14 million per QALY at year 6 to <¥6 million at year 10, approaching the Japanese WTP threshold of ¥5 million per QALY. ICER = incremental cost-effectiveness ratio; JPY = Japanese yen; QALY = quality-adjusted life-year; WTP = willingness-to-pay; other abbreviations as in Figure 1.

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  Figure 3. Deterministic Sensitivity Analyses in the Base-Case Analysis Tornado diagram shows the impact of key model parameters on the ICER of TAVI vs MICS-AVR. Blue bars represent the ICER when each parameter was set at the lower bound of its predefined range, whereas red bars represent the ICER when the parameter was set at the upper bound. Postoperative utility beyond 1 year had the greatest influence, followed by all-cause mortality during the chronic phase and device/procedural costs. The vertical lines indicate the base-case ICER (black) and the Japanese WTP threshold of ¥5 million per QALY (magenta). Abbreviations as in Figures 1 and 2.

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  Figure 4. Two-Way Deterministic Sensitivity Analysis 2-dimensional plot illustrates the cost-effectiveness regions according to simultaneous variations in device and procedural costs for TAVI and MICS-AVR. As the cost difference between the 2 strategies narrowed, the cost-effectiveness frontier shifted in favor of TAVI, emphasizing the impact of cost containment on its economic value. Abbreviations as in Figures 1 and 2.

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  Figure 5. Cost-Effectiveness Acceptability Curves Acceptability curves illustrate the probability of each strategy being cost-effective across a range of WTP thresholds. The curves intersected at approximately ¥6 million per QALY, indicating that TAVI was not cost-effective at the conventional Japanese threshold of ¥5 million per QALY but achieved cost-effectiveness under a higher threshold of ¥7 million per QALY. Abbreviations as in Figures 1 and 2.

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  Figure 6. Probabilistic Sensitivity Analysis Results (A and B) Incremental cost-effectiveness scatterplots derived from 10,000 Monte Carlo simulations at WTP thresholds of ¥5 million (A) and ¥7 million (B) per QALY. Each dot represents 1 simulation. Blue dots indicate simulations in which transcatheter aortic valve implantation was cost-effective at the specified WTP threshold, whereas red dots indicate simulations in which it was not. The proportion of simulations in which transcatheter aortic valve implantation was cost-effective was 49.4% at a WTP of ¥5 million per QALY and 53.9% at ¥7 million per QALY. Abbreviations as in Figure 2.

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  Central Illustration. Cost-Effectiveness of TAVI vs MICS-AVR Summary of the decision analytical model and principal findings. A hybrid model consisting of a periprocedural decision tree and a long-term Markov process was used to compare TAVI and MICS-AVR in low-risk AS over a 10-year horizon. In the base-case analysis, TAVI demonstrated slightly higher QALYs at greater cost, resulting in a borderline ICER near the Japanese WTP of ¥5 million per QALY. Probabilistic sensitivity analysis indicated substantial decision uncertainty. In a scenario reflecting high-volume surgical centers, MICS-AVR became economically dominant. Overall, relative cost-effectiveness depends strongly on postoperative utility and institutional performance. AS = aortic stenosis; HF = heart failure; ICER = incremental cost-effectiveness ratio; JPY = Japanese yen; MICS-AVR = minimally invasive surgical aortic valve replacement; PMI = permanent pacemaker implantation; QALY = quality-adjusted life-year; RCT = randomized controlled trial; SVD = structural valve deterioration; TAVI = transcatheter aortic valve implantation; WTP = willingness-to-pay.