OBJECTIVE: Compare TEG parameters between clopidogrel-resistant and clopidogrel-non-resistant groups.

SUMMARY BACKGROUND DATA: Graft or stent thrombosis affects 1 in 5 patients within six months post-revascularization and is a leading cause of amputation in the elderly. Clopidogrel resistance occurs in 5-44% of patients.

METHODS: This prospective observational study evaluated patients with PAD undergoing revascularization and taking clopidogrel between 2022 and 2024. Whole blood samples were analyzed using thromboelastography (TEG) and VerifyNow testing. Patients were categorized based on their clopidogrel response: clopidogrel-resistant (>180 P2Y12 Reaction Units (PRU)) and non-resistant (<180 PRU). Fisher's exact and Wilcoxon tests were used to compare the groups for categorical and continuous variables, respectively. Spearman's correlation coefficient was used to determine the relationship between platelet function and clopidogrel response (VerifyNow).

RESULTS: Fifty-three patients were analyzed, 70% were male, and 23% were clopidogrel-resistant. Clopidogrel-resistant exhibited higher platelet reactivity (PRU 224.2 vs. 74.9, P<0.0001), faster clot formation (1.14min vs. 1.22min, P<0.0001), clot strength (ADP-MA 54.9 mm vs. 39.8 mm, P<0.0001), and reduced clot lysis (0.97min vs. 0.69min, P=0.0005) compared to non-resistant. Additionally, these patients showed a higher percentage of platelet aggregation (74.0% vs. 44.0%, P<0.0001) and a lower platelet inhibition (26.0% vs. 56.0%, P<0.0001), indicating a diminished response to clopidogrel and an increased risk of thrombosis.

CONCLUSION: Clopidogrel-resistant group exhibited faster clot formation, greater clot strength, and higher platelet aggregation. Incorporating TEG into clinical practice could help identify patients at risk of inadequate clopidogrel response.