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Total thrombus‐formation analysis system (T‐TAS) quantitatively measures platelet thrombus formation. We examined the utility of T‐TAS in patients with coronary artery disease. T‐TAS can discriminate different types of the antiplatelet therapy in the same measuring method. Genetic background, cytochrome P‐450 2C19 genotypes, also influenced T‐TAS parameters. Summary BackgroundAccurate evaluation of thrombogenicity helps to prevent thrombosis and excessive bleeding. The total thrombus‐formation analysis system (T‐TAS) was developed for quantitative analysis of platelet thrombus formation by the use of microchips with thrombogenic surfaces (collagen, platelet chip [PL‐chip]; collagen plus tissue factor, atherome chip [AR‐chip]). We examined the utility of the T‐TAS in the assessment of the efficacy of antiplatelet therapy in patients with coronary artery disease (CAD). Methods and ResultsIn this cross‐sectional study, 372 consecutive patients admitted to the cardiovascular department were divided into three groups: patients not receiving any antiplatelet therapy (control, n = 56), patients receiving aspirin only (n = 69), and patients receiving aspirin and clopidogrel (n = 149). Blood samples were used for the T‐TAS to measure the platelet thrombus‐formation area under the curve (AUC) at various shear rates (1500 s−1 [PL18‐AUC10] and 2000 s−1 [PL24‐AUC10] for the PL‐chip; 300 s−1 [AR10‐AUC30] for the AR‐chip). The on‐clopidogrel platelet aggregation was measured by the use of P2Y12 reaction units (PRUs) with the VerifyNow system. The mean PL24‐AUC10 levels were 358 ± 111 (± standard deviation) (95% confidence interval [CI] 328.9–387.1) in the control group, 256 ± 108 (95% CI 230.5–281.5) in the aspirin group, and 113 ± 91 (95% CI 98.4–127.6) in the aspirin/clopidogrel group. In the aspirin/clopidogrel group, the PL24‐AUC10 was higher in poor metabolizers (PMs) with cytochrome P450 2C19(CYP2C19) polymorphisms (152 ± 112, 95% CI 103.4–200.6) than in the non‐PM group (87 ± 74, 95% CI 73.8–100.2). ConclusionsOur findings suggest that the PL24‐AUC10 level measured by the T‐TAS is a potentially suitable index for the assessment of antiplatelet therapy in CAD patients.

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BackgroundNon–vitamin K antagonist oral anticoagulants are used to prevent thromboembolism in patients with atrial fibrillation. The T‐TAS “Total Thrombus‐formation Analysis System” (Fujimori Kogyo Co Ltd) was developed for quantitative analysis of thrombus formation using microchips with thrombogenic surfaces (collagen, platelet chip [PL] ; collagen plus tissue factor, atheroma chip [AR]). We evaluated the utility of T‐TAS in predicting periprocedural bleeding in atrial fibrillation patients undergoing catheter ablation (CA).Methods and ResultsAfter exclusion of 20 from 148 consecutive patients undergoing CA, the remaining 128 patients were divided into 2 treatment groups: the warfarin group (n=30) and the non–vitamin K antagonist oral anticoagulants group (n=98). Blood samples obtained on the day of CA (anticoagulant‐free point) and at 3 and 30 days after CA were used in T‐TAS to compute the thrombus formation area under the curve (AUC; AUC for the first 10 minutes for PL tested at flow rate of 24 μL/min [PL 24‐AUC 10]; AUC for the first 30 minutes for AR tested at flow rate of 10 μL/min [AR 10‐AUC 30]). AR 10‐AUC 30 and PL 24‐AUC 10 levels were similar in the 2 groups on the day of CA. Levels of AR 10‐AUC 30, but not PL 24‐AUC 10, were significantly lower in the 2 groups at days 3 and 30 after CA. Multiple logistic regression analyses identified the AR 10‐AUC 30 level on the day of CA as a significant predictor of periprocedural bleeding events (odds ratio 5.7; 95% CI 1.54–21.1; P=0.009). Receiver operating characteristic analysis showed that the AR 10‐AUC 30 level on the day of CA significantly predicted periprocedural bleeding events (AUC 0.859, 95% CI 0.766–0.951; P<0.001). The cutoff AR 10‐AUC 30 level was 1648 for identification of periprocedural bleeding events.ConclusionsThese results suggested that the AR 10‐AUC 30 level determined by T‐TAS is a potentially useful marker for prediction of bleeding events in atrial fibrillation patients undergoing CA.

BackgroundPeriprocedural bleeding events are common after percutaneous coronary intervention. We evaluated the association of periprocedural bleeding events with thrombogenicity, which was measured quantitatively by the Total Thrombus‐formation Analysis System equipped with microchips and thrombogenic surfaces (collagen, platelet chip [PL]; collagen plus tissue factor, atheroma chip [AR]).Methods and ResultsBetween August 2013 and March 2016, 313 consecutive patients with coronary artery disease undergoing elective percutaneous coronary intervention were enrolled. They were divided into those with or without periprocedural bleeding events. We determined the bleeding events as composites of major bleeding events defined by the International Society on Thrombosis and Hemostasis and minor bleeding events (eg, minor hematoma, arteriovenous shunt and pseudoaneurysm). Blood samples obtained at percutaneous coronary intervention were analyzed for thrombus formation area under the curve (PL24‐AUC10 for PL chip; AR10‐AUC30 for AR chip) by the Total Thrombus‐formation Analysis System and P2Y12 reaction unit by the VerifyNow system. Periprocedural bleeding events occurred in 37 patients. PL24‐AUC10 levels were significantly lower in patients with such events than those without (P=0.002). Multiple logistic regression analyses showed association between low PL24‐AUC10 levels and periprocedural bleeding events (odds ratio, 2.71 [1.22–5.99]; P=0.01) and association between PL24‐AUC10 and periprocedural bleeding events in 176 patients of the femoral approach group (odds ratio, 2.88 [1.11–7.49]; P=0.03). However, PL24‐AUC10 levels in 127 patients of the radial approach group were not significantly different in patients with or without periprocedural bleeding events.ConclusionsPL24‐AUC10 measured by the Total Thrombus‐formation Analysis System is a potentially useful predictor of periprocedural bleeding events in coronary artery disease patients undergoing elective percutaneous coronary intervention.