Cost Effectiveness Of Antiplatelet Therapy Following Lower Extremity Endovascular Interventions
Kyle Markel, Natalie Sridharan, Efthimios Avgerinos, Mohammad Eslami, Michael Madigan, Kenneth Smith.
University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
OBJECTIVES: Dual antiplatelet therapy with 81mg aspirin and clopidogrel is commonly prescribed following lower extremity endovascular interventions. However, emerging evidence suggests that not all patients respond equally to clopidogrel therapy, which has been termed clopidogrel resistance or high on-treatment platelet reactivity (HoTPR). While clopidogrel is relatively inexpensive, patients with HoTPR may be at increased risk of intervention failure. Our goal with this study was to compare different antiplatelet prescribing strategies following lower extremity femoropopliteal endovascular interventions using cost effectiveness modeling hypothesizing that tailored antiplatelet therapy would be cost effective. METHODS: We used a one-year decision analytic model to compare cost effectiveness among four antiplatelet management strategies in patients undergoing femoropopliteal endovascular interventions for peripheral arterial disease: empiric clopidogrel (EC), empiric ticagrelor (ET), pharmacogenetic testing guided antiplatelet therapy (PGx), and platelet function testing guided antiplatelet therapy (PFT). In the latter two strategies, ticagrelor would be prescribed to patients with HoTPR, otherwise the patient would continue to receive clopidogrel. Effectiveness was measured using published cumulative patency rates when available. Medication costs along with procedural and testing reimbursement (in US dollars) were estimated using recently published cost data. RESULTS: The least expensive strategy is empiric clopidogrel (EC), however it is also the least effective with 70% cumulative patency rate at one year. The next least expensive strategy is tailored antiplatelet therapy using pharmacogenetic testing (PGx), which costs $133 per patient more annually. This increased cost comes with higher cumulative patency of 76%, which offers an additional 6% absolute patency likelihood compared to EC. We estimated a willingness to pay (WTP) threshold of $8249, which is equal to our estimated cost for reintervention. Choosing PGx over EC costs $2404 more annually to prevent loss of patency per limb over 1 year. This result is below the WTP making PGx the preferred strategy. Both tailored antiplatelet therapy using platelet function testing and using empiric ticagrelor are less effective and more expensive than EC and PGx. CONCLUSIONS: Our model supports empiric clopidogrel, the current guideline-based therapy for lower extremity arterial endovascular interventions, as the least expensive strategy. However, at a willingness to pay threshold equal to estimated reintervention costs, favored antiplatelet strategy is pharmacogenetic testing with tailored antiplatelet therapy using ticagrelor in place of clopidogrel for patients with HoTPR.
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