The Use of Clot Strength as a Predictor of Thrombosis in Peripheral Artery Disease

Graft/stent thrombosis is the leading cause of amputation in patients over 60, and while dual antiplatelet therapy is the standard of care, there is a significant variability in platelet response and limited guidance on measuring effectiveness. Thromboelastography with platelet mapping (TEG-PM) can objectively detail an individual's coagulation profile, namely the strength of the clot and its response to antiplatelet medication. Although TEG-PM has been used for predicting postoperative bleeding and assessing platelet dysfunction in traumatic brain injury, its application in thrombosis diseases such as peripheral artery disease remains unexplored. The aim of this observational study was to determine if objective measures of clot strength could predict a high clinical risk of thrombosis.

Patients >60 years with peripheral artery disease undergoing revascularization were prospectively evaluated from 2021 to 2023. They were clinically followed for 1 year to detect any thrombotic events. TEG-PM was used to objectively evaluate coagulation profiles in patients at 1, 3, 6, and 9 months. These follow-up periods were chosen based on studies showing that 1-3 month intervals in the first year after lower extremity revascularization optimize therapy and risk control. The TEG-PM data preceding a thrombotic/stenotic event in patients with thrombosis was compared to the last known well TEG-PM event in those without a thrombotic/stenotic event. We stratified the groups based on the occurrence of thrombosis/stenotic events. Descriptive statistics were applied to characterize each group and a chi-square test was conducted to assess the variance between both groups. An unpaired t-test was run to identify differences in platelet function. Receiver operating characteristic analysis was performed to determine the optimal TEG-PM cutoff for predicting a higher risk of thrombosis.

One hundred and fifty-eight patients were analyzed, from whom 28 (17.7%) experienced a thrombotic event. The thrombosis cohort exhibited significantly greater MA_ADP, MA_Fibrin, and MA_Thrombin [50.2 vs. 40.0, P < 0.05], [18.19 vs. 14.64, P < 0.05], and [63.8 vs. 58.5, P < 0.05], respectively, indicative of greater clot strength. By receiver operating characteristic analysis, the optimal predictor cut-off for MA_ADP, indicating a higher risk of thrombosis, was >42 mm [P < 0.05] with 82% sensitivity and 50% specificity.

An increase in clot strength was found to be predictive of thrombosis/stenosis within 30 days. Using a MA_ADP cut-off greater than 42 mm might serve as an alternative approach to tailor the use of antiplatelet medication, potentially reducing the risk of thrombosis.