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Thrombelastography Compared with Multiple Impedance Aggregometry to Assess High On-Clopidogrel Reactivity in Patients
Diona Gjermeni1, Hannah Vetter1, Sofia Szabó1
1Department of Cardiology and Angiology, Heart Center Freiburg University, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany.
Insights
High on-clopidogrel platelet reactivity (HPR) is common in atrial fibrillation (AF) patients after PCI, especially when assessed by thrombelastography (TEG). Conventional HPR definitions may need re-evaluation in this high-risk group.
Area of Science:
- Cardiology
- Thrombosis
- Interventional Cardiology
Background:
- High on-clopidogrel platelet reactivity (HPR) after percutaneous coronary intervention (PCI) increases ischemic risk.
- The applicability of conventional HPR definitions in patients on oral anticoagulation (OAC) is uncertain.
- Atrial fibrillation (AF) patients undergoing PCI often require OAC, creating a complex clinical scenario.
Purpose of the Study:
- To compare multiple platelet aggregometry (MEA) and thrombelastography (TEG) in detecting HPR in AF patients indicated for OAC post-PCI.
- To evaluate the performance of established HPR cut-off values in this specific patient population.
Main Methods:
- Observational, single-center cohort study.
- MEA and TEG performed on days 1-3 post-PCI in 39 AF patients indicated for OAC.
- Primary outcome: HPR defined by MEA (ADP AUC ≥ 46 U) or TEG (MAADP ≥ 47 mm).
Main Results:
- The rate of HPR was significantly higher when assessed by TEG (64%) compared to MEA (3%).
- Median ADP-induced aggregation was 9 U, and MAADP was 50 mm.
- Within 6 months, the cohort experienced 10% deaths, 3% MI, and 23% bleeding events.
Conclusions:
- TEG detects significantly higher rates of HPR than MEA in AF patients undergoing PCI.
- Conventional HPR cut-off values may require re-evaluation for this high-risk population.
- Further research is needed to correlate these findings with clinical outcomes.
Abstract:
Background: High on-clopidogrel platelet reactivity (HPR) following percutaneous coronary intervention (PCI) is associated with increased ischemic risk. It is unclear whether conventional definitions of HPR apply to patients with concomitant oral anticoagulation (OAC). This study aimed to compare the performance of multiple platelet aggregometry (MEA) and thrombelastography (TEG) to detect HPR in patients with atrial fibrillation (AF) and indication for an OAC. Methods: In this observational single-center cohort study, MEA and TEG were performed in patients with AF with an indication for OAC on day 1 to 3 after PCI. The primary outcome was HPR as assessed by MEA (ADP area under the curve ≥ 46 units [U]) or TEG (MAADP ≥ 47 mm), respectively. The secondary exploratory outcomes were a composite of all-cause death, myocardial infarction (MI) or stroke and bleeding, as defined by the International Society on Thrombosis and Hemostasis, at 6 months. Results: Platelet function of 39 patients was analyzed. The median age was 78 (interquartile range [IQR] was 72−82) years. 25 (64%) patients were male, and 19 (49%) presented with acute coronary syndrome. All patients received acetylsalicylic acid and clopidogrel prior to PCI. Median (IQR) ADP-induced aggregation, MAADP, TRAP-induced aggregation, and MAthrombin were 9 (6−15) U, 50 (43−60) mm, 54 (35−77) U and 65 (60−67) mm, respectively. The rate of HPR was significantly higher if assessed by TEG compared with MEA (25 [64%] vs. 1 [3%]; p < 0.001). Within 6 months, four (10%) deaths, one (3%) MI and nine (23%) bleeding events occurred. Conclusion: In patients with AF undergoing PCI, the rates of HPR detected by TEG were significantly higher compared with MEA. Conventional cut-off values for HPR as proposed by consensus documents may need to be re-evaluated for this population at high ischemic and bleeding risk. Further studies are needed to assess the association with outcomes.
