Thrombin-induced platelet-fibrin clot strength: Relation to high on-clopidogrel platelet reactivity, genotype, and post-percutaneous coronary intervention outcomes

Diabetic Status and Thrombogenicity: Association and Prognostic Implications After Percutaneous Coronary Intervention

BACKGROUND

A heightened prothrombotic environment, combined with premature and more aggressive atherosclerosis, contributes to the elevated cardiovascular risk in patients with diabetes mellitus (DM).

OBJECTIVES

The aim of this study was to evaluate the association between DM status and thrombogenicity and their prognostic implications in patients with significant coronary artery disease.

METHODS

A total of 2,501 patients with coronary artery disease undergoing percutaneous coronary intervention, with on-admission glycated hemoglobin and thrombogenicity indexes (measured by thromboelastography). Major adverse cardiovascular events (MACE) were defined as a composite of all-cause death, myocardial infarction, or stroke within 4-year follow-up.

RESULTS

Patients with DM (n = 970 [38.8%]) demonstrated significantly higher platelet-fibrin clot strength (PFCS), as indicated by maximal amplitude (median [Q1-Q3]: 67.1 [62.2-72.2] mm vs. 65.5 [61.0-70.4] mm; P < 0.001), and reduced fibrinolytic activity, measured by lysis at 30 minutes (median [Q1-Q3]: 0.1% [0.0%-1.0%] vs. 0.2% [0.0%-1.3%]; P = 0.003), compared to patients without DM. PFCS level was closely related with diabetic status, showing a positive relationship with glycated hemoglobin level up to 7.0% and then reaching a plateau. In a multivariable analysis, high PFCS phenotype defined as maximal amplitude ≥68 mm (HR: 1.39; 95% CI: 1.07-1.81; P = 0.015) and DM phenotype (HR: 1.38; 95% CI: 1.05-1.79; P = 0.018) were independently associated with MACE occurrence. The presence of diabetic phenotype and high PFCS exhibited an additive effect on MACE occurrence (HR: 2.49; 95% CI: 1.77-3.51; P < 0.001).

CONCLUSIONS

In percutaneous coronary intervention-treated patients, diabetic status and clot-strength value were significantly correlated. High clot-strength phenotype increased the risk for MACE, irrespective of diabetic phenotype. (Gyeongsang National University Hospital Registry [GNUH]; NCT04650529).

Association Between Thromboelastography and Coagulation for Disease Severity Evaluation in Patients With Lower Extremity Arteriosclerosis Obliterans

BACKGROUND

Thromboelastography (TEG) and coagulation tests can be used to detect hypercoagulability to assess thrombus formation. This study explored the association between TEG and coagulation in evaluating disease severity in elderly patients with lower extremity arteriosclerotic occlusive disease (LEASO), aimed to provide surgical treatment guideline.

METHODS

We retrospectively analyzed the clinical characteristics, laboratory biomarkers, TEG and coagulation parameters of 233 elderly LEASO patients treated between 2020 and 2023. Among them, 86 underwent surgical amputation, 51 received vascular intervention, and the remaining were treated conservatively. Differences in TEG and coagulation among the three groups were assessed using Spearman's correlation. Multivariate logistic regression and receiver operating characteristic curves analyzed the relationships among TEG, fibrinogen (FIB), and D-dimer (D-D) levels for surgical evaluation.

RESULTS

Inflammatory factors, platelet counts, and Fontaine stages III-IV differed significantly between the surgery and conservative groups (p < 0.05). The surgery group had higher α-angle, maximum amplitude (MA), coagulation comprehensive index (CI), FIB, and D-D, whereas lower clotting time (K) compared to the conservative group (p < 0.05), correlated with a lower ankle brachial index (ABI), indicating more severe clinical presentation. Spearman's analysis identified positive associations between α-angle, MA with FIB and D-D levels in surgical patients. Area under curve analysis indicated that combining MA, α-angle, FIB, and D-D could enhance accuracy in evaluating surgical necessity in LEASO.

CONCLUSION

In elderly LEASO patients, TEG and coagulation analysis revealed a positive association between thrombus intensity and disease severity. Increased MA, α-angle, FIB, and D-D levels serve as predictors for surgical treatment necessity in LEASO.

Platelet-fibrin clot strength and platelet reactivity predicting cardiovascular events after percutaneous coronary interventions

BACKGROUND AND AIMS

Platelet-fibrin clot strength (PFCS) is linked to major adverse cardiovascular event (MACE) risk. However, the association between PFCS and platelet reactivity and their prognostic implication remains uncertain in patients undergoing percutaneous coronary intervention (PCI).

METHODS

In PCI-treated patients (n = 2512) from registry data from January 2010 to November 2018 in South Korea, PFCS using thromboelastography and platelet reactivity using VerifyNow were measured. High PFCS (PFCSHigh) was defined as thromboelastography maximal amplitude ≥ 68 mm, and high platelet reactivity (HPR) was defined as >208 P2Y12 reaction units. Patients were stratified into four groups according to maximal amplitude and P2Y12 reaction unit levels: (i) normal platelet reactivity (NPR)-PFCSNormal (31.8%), (ii) HPR-PFCSNormal (29.0%), (iii) NPR-PFCSHigh (18.1%), and (iv) HPR-PFCSHigh (21.1%). Major adverse cardiovascular event (all-cause death, myocardial infarction, or stroke) and major bleeding were followed up to 4 years.

RESULTS

High platelet reactivity and PFCSHigh showed an additive effect for clinical outcomes (log-rank test, P < .001). Individuals with NPR-PFCSNormal, NPR-PFCSHigh, HPR-PFCSNormal, and HPR-PFCSHigh demonstrated MACE incidences of 7.5%, 12.6%, 13.4%, and 19.3%, respectively. The HPR-PFCSHigh group showed significantly higher risks of MACE compared with the NPR-PFCSNormal group [adjusted hazard ratio (HRadj) 1.89; 95% confidence interval (CI) 1.23-2.91; P = .004] and the HPR-PFCSNormal group (HRadj 1.60; 95% CI 1.12-2.27; P = .009). Similar results were observed for all-cause death. Compared with HPR-PFCSNormal phenotype, NPR-PFCSNormal phenotype was associated with a higher risk of major bleeding (HRadj 3.12; 95% CI 1.30-7.69; P = .010).

CONCLUSIONS

In PCI patients, PFCS and platelet reactivity demonstrated important relationships in predicting clinical prognosis. Their combined assessment may enhance post-PCI risk stratification for personalized antithrombotic therapy.

Portal vein thrombosis associates with high platelet-fibrin clot strength and platelet activation in decompensated cirrhosis: A retrospective study

BACKGROUND AND AIMS

Alteration of platelet status associates with decompensation and death in cirrhosis, while its effect on portal vein thrombosis (PVT) remains unclear. We aimed to retrospectively investigate whether PVT associates with platelet-fibrin clot strength and platelet activation in decompensated cirrhosis.

METHODS

Platelet-fibrin clot strength (G) was measured by thromboelastography (TEG). Platelet activation was reflected by plasma concentrations of soluble p-selectin (sPs) and a platelet aggregation test adjusted for platelet counts.

RESULTS

Among 166 patients, 45 had PVT. The platelet count was significantly lower in PVT. While the G value was positively correlated with platelet count (ρ = 0.74, P < 0.01), increased G was associated with PVT after adjusting for platelet count in the logistic regression (P = 0.04). The normalized G value according to the linear relation with platelet count was calculated as follows: G_platelet = [(G - 2622)/platelet count]. This coefficient had no correlation with platelet count and was an independent risk factor of PVT (OR = 1.03, CI_95%: 1.01-1.05, P = 0.012). In two subanalyses, the collagen-induced platelet aggregation (n = 37, P = 0.029) and plasma concentration of sPs (n = 56, P = 0.001) adjusted for platelet count were significantly higher in PVT.

CONCLUSION

This study showed a positive correlation of high platelet-fibrin clot strength detected via TEG and platelet activation with PVT in decompensated cirrhosis.

Association between kaolin-induced maximum amplitude and slow-flow/no-reflow in ST elevation myocardial infarction patients treated with primary percutaneous coronary intervention

BACKGROUND

ST-segment elevation myocardial infarction (STEMI) patients with a high thrombus burden have a relatively high slow-flow/no-reflow risk. However, the association between kaolin-induced maximum amplitude (MA_thrombin) and slow-flow/no-reflow has been scarcely explored.

METHODS

STEMI patients treated with primary percutaneous coronary intervention (PCI) were retrospectively enrolled from January 2015 to December 2019 at China-Japan Friendship Hospital. MA_thrombin levels were measured using thromboelastography before the PCI procedure. The patients were divided into two groups according to thrombolysis in myocardial infarction (TIMI) flow grade after primary PCI: the normal flow group (TIMI flow grade = 3) and slow-flow/no-reflow (TIMI flow grade ≤ 2). The logistic regression model and restricted cubic spline regression (RCS) were used to analyze the predictive value of MA_thrombin for slow-flow/no-reflow. All patients were followed up after discharge and observed the adverse cardiovascular events between the two groups.

RESULTS

A total of 690 patients were enrolled, with 108(15.7%) having slow-flow/no-reflow. The multivariate logistic regression model analysis showed that MA_thrombin level was an independent risk factor for slow-flow/no-reflow. The RCS analysis showed a nonlinear relationship between MA_thrombin levels and slow-flow/no-reflow. The cut-off value of MA_thrombin levels for predicting slow-flow/no-reflow was 68 mm. During a median follow-up time of 4.4 years, slow-flow/no-reflow (hazard ratio 1.93, 95% confidence interval 1.27-2.93, P = 0.002) and MA_thrombin levels (hazard ratio 1.06, 95% confidence interval 1.03-1.08, P < 0.001) were independent risk factors for predicting the long-term of adverse clinical cardiovascular events.

CONCLUSION

MA_thrombin was an independent risk factor for predicting slow-flow/ no-reflow in STEMI patients who underwent primary PCI.

Association Between Thrombogenicity Indices and Coronary Microvascular Dysfunction in Patients With Acute Myocardial Infarction

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Our study supports the feasibility of measuring thrombogenicity in patients with acute myocardial infarction, with intent to predict periprocedural and long-term clinical events, in real-world clinical practice.

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Preprocedural assessment of ex vivo thrombogenicity (eg, platelet-fibrin clot strength by thromboelastography) was significantly associated with the risk of coronary microvascular dysfunction.

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A combined risk stratification with coronary microvascular dysfunction and platelet-fibrin clot strength increased the prognostic implication to predict the rates of long-term clinical outcomes.

The association between thrombogenicity and coronary microvascular dysfunction (CMD) has been poorly explored in patients with acute myocardial infarction (AMI). In our real-world clinical practice (N = 116), thrombogenicity was evaluated with thromboelastography and conventional hemostatic measures, and CMD was defined as index of microcirculatory resistance of >40 U using the invasive physiologic test. High platelet-fibrin clot strength (P-FCS) (≥68 mm) significantly increased the risk of postprocedural CMD (odds ratio: 4.35; 95% CI: 1.74-10.89). Patients with both CMD and high P-FCS had a higher rate of ischemic events compared to non-CMD subjects with low P-FCS (odds ratio: 5.58; 95% CI: 1.31-23.68). This study showed a close association between heightened thrombogenicity and CMD and their prognostic implications after reperfusion in acute myocardial infarction patients.

The role of viscoelastic testing in assessing peri-interventional platelet function and coagulation

We carried out a literature search in MEDLINE (PubMed) and EMBASE literature databases to provide a concise review of the role of viscoelastic testing in assessing peri-interventional platelet function and coagulation. The search identified 130 articles that were relevant for the review, covering the basic science of VHA and VHA in clinical settings including cardiac surgery, cardiology, neurology, trauma, non-cardiac surgery, obstetrics, liver disease, and COVID-19. Evidence from these articles is used to describe the important role of VHAs and platelet function testing in various peri-interventional setups. VHAs can help us to comprehensively assess the contribution of platelets and coagulation dynamics to clotting at the site-of-care much faster than standard laboratory measures. In addition to standard coagulation tests, VHAs are beneficial in reducing allogeneic transfusion requirements and bleeding, in predicting ischemic events, and improving outcomes in several peri-interventional care settings. Further focused studies are needed to confirm their utility in the peri-interventional case.

Effects of Monotherapy with Clopidogrel vs. Aspirin on Vascular Function and Hemostatic Measurements in Patients with Coronary Artery Disease: The Prospective, Crossover I-LOVE-MONO Trial

OBJECTIVES

To evaluate the effect of clopidogrel vs. aspirin monotherapy on vascular function and hemostatic measurement.

BACKGROUND

Monotherapy with P2Y12 receptor inhibitor vs. aspirin can be a useful alterative to optimize clinical efficacy and safety in high-risk patients with coronary artery disease (CAD).

METHODS

We performed a randomized, open-label, two-period crossover study in stented patients receiving at least 6-month of dual antiplatelet therapy (DAPT). Thirty CAD patients with moderate-to-high ischemic risk were randomly assigned to receive either 75 mg of clopidogrel or 100 mg of aspirin daily for 4 weeks, and were crossed over to the other strategy for 4 weeks. Vascular function was evaluated with reactive hyperemia-peripheral arterial tonometry (RH-PAT) and brachial-ankle pulse wave velocity (baPWV). Hemostatic profiles were measured with VerifyNow and thromboelastography (TEG). The primary endpoint was the reactive hyperemia index (RHI) during clopidogrel or aspirin monotherapy.

RESULTS

Clopidogrel vs. aspirin monotherapy was associated with better endothelial function (RHI: 2.11 ± 0.77% vs. 1.87 ± 0.72%, p = 0.045), lower platelet reactivity (130 ± 64 vs. 214 ± 50 P2Y12 reaction unit [PRU], p < 0.001) and prolonged reaction time (TEG R: 5.5 ± 1.2 vs. 5.1 ± 1.1 min, p = 0.037). In multivariate analysis, normal endothelial function (RHI ≥ 2.1) was significantly associated with clot kinetics (TEG angle ≤ 68 degree) and 'PRU ≤ 132'. 'PRU ≤ 132' was achieved in 46.2% vs. 3.8% during clopidogrel administration vs. aspirin monotherapy (odds ratio 21.4, 95% confidence interval 2.7 to 170.1, p < 0.001).

CONCLUSIONS

In CAD patients, clopidogrel vs. aspirin monotherapy was associated with better endothelial function, greater platelet inhibition and lower coagulation activity, suggesting pleiotropic effects of clopidogrel on endothelial function and hemostatic profiles.

The East Asian Paradox: An Updated Position Statement on the Challenges to the Current Antithrombotic Strategy in Patients with Cardiovascular Disease

East Asian patients have reduced anti-ischemic benefits and increased bleeding risk during antithrombotic therapies compared with Caucasian patients. As potent P2Y12 receptor inhibitors (e.g., ticagrelor and prasugrel) and direct oral anticoagulants are commonly used in current daily practice, the unique risk-benefit trade-off in East Asians has been a topic of emerging interest. In this article, we propose updated evidence and future directions of antithrombotic treatment in East Asian patients.

Ethnic Difference of Thrombogenicity in Patients with Cardiovascular Disease: a Pandora Box to Explain Prognostic Differences

Arterial and venous atherothrombotic events are finely regulated processes involving a complex interplay between vulnerable blood, vulnerable vessel, and blood stasis. Vulnerable blood ('thrombogenicity') comprises complex interactions between cellular components and plasma factors (inflammatory, procoagulant, anticoagulant, and fibrinolytic factors). The extent of thrombogenicity may determine the progression of atheroma and the clinical manifestation of atherothrombotic events, with the highest thrombogenicity in African Americans and lowest in East Asians. Inherent thrombogenicity may influence clinical efficacy and safety of specific antithrombotic treatments in high-risk patients, which may in part explain the observation that East Asian patients have reduced anti-ischemic benefits and elevated bleeding risk with antithrombotic therapy compared to Caucasian patients. In this review, we discuss available evidence regarding the racial differences in thrombogenicity and its impact on clinical outcomes among patients with atherosclerotic cardiovascular disease.

The Impact of platelet-fibrin clot strength on occurrence and clinical outcomes of peripheral artery disease in patients with significant coronary artery disease

Patients with peripheral artery disease (PAD) have shown the increased risk of cardiovascular (CV) morbidity and mortality. This study sought to evaluate the impact of clot strength on prevalence and major adverse CV events (MACE) of PAD in high-risk patients. We enrolled patients undergoing percutaneous coronary intervention (PCI) (n = 1667) with available platelet-fibrin clot strength [thrombin-induced maximal amplitude (MAthrombin) measured by thromboelastography] and inflammation [high sensitivity C-reactive protein (hs-CRP)]. PAD was defined with abnormal ankle-brachial index (≤ 0.9 or > 1.4). MACE was defined as a composite of CV death, myocardial infarction or stroke. PAD was observed in 201 patients (12.1%). In the multivariate analysis, high clot strength [MAthrombin ≥ 68 mm: odds ratio (OR) 1.70, 95% confidence interval (CI) 1.20 to 2.41, p = 0.003] and enhanced inflammation (hs-CRP ≥ 3.0 mg/L: OR 2.30, 95% CI 1.56 to 3.41, p < 0.001) were associated with PAD occurrence. During the follow-up post-PCI (median, 25 months), MACE was more frequently occurred in patients with vs. without PAD (18.7% vs. 6.4% at 3 years; hazard ratio 1.72, 95% CI 1.03 to 2.87, p = 0.039). Furthermore, combined presence of PAD and high clot strength significantly increased the risk of MACE. In conclusion, this study is the first to show the impact of clot strength on prevalence and clinical outcomes of PAD in coronary artery disease patients undergoing PCI. Whether antithrombotic strategy according to level of this biomarker can improve clinical outcomes in PAD patients deserves the further study.

Viscoelastic properties of clot formation and their clinical impact in East Asian versus Caucasian patients with stable coronary artery disease: a COMPARE-RACE analysis

Compared with Caucasian patients, East Asian patients with coronary artery disease (CAD) have demonstrated better clinical outcomes. We sought to compare the viscoelastic properties of clot formation and their impact on clinical outcomes in East Asian vs. Caucasian patients. We analyzed age- and sex-matched East Asian and Caucasian patients with stable CAD (n = 249 each). Viscoelastic properties of clot formation were assessed with thromboelastography (TEG), and 3-year clinical outcomes were recorded. Major adverse cardiovascular events (MACE) were defined as a composite of cardiovascular death, myocardial infarction, or stroke. Compared with Caucasians, East Asians showed lower platelet-fibrin clot strength (PFCS) (maximum amplitude [MA]: 61.8 ± 7.9 vs. 65.4 ± 5.0 mm, p < 0.001). In a multivariate analysis, high PFCS (defined as MA ≥ 68 mm) was significantly associated with MACE occurrence (odds ratio 6.27, 95% CI 2.41 to 16.30, p < 0.001). East Asians vs. Caucasians had lower prevalence of high PFCS (odds ratio 0.50, 95% CI 0.27 to 0.93, p = 0.028). In conclusion, this is the first study to demonstrate different viscoelastic properties of clot between East Asian and Caucasian patients with stable CAD. The platelet-fibrin clot strength was significantly associated with MACE in these patients and was significantly lower in East Asians. Future studies are warranted to further explore the mechanistic explanation and clinical importance of these findings.

Adjunctive Cilostazol to Dual Antiplatelet Therapy to Enhance Mobilization of Endothelial Progenitor Cell in Patients with Acute Myocardial Infarction: A Randomized, Placebo-Controlled EPISODE Trial

BACKGROUND

Endothelial progenitor cells (EPCs) have the potential to protect against atherothrombotic event occurrences. There are no data to evaluate the impact of cilostazol on EPC levels in high-risk patients.

METHODS

We conducted a randomized, double-blind, placebo-controlled trial to assess the effect of adjunctive cilostazol on EPC mobilization and platelet reactivity in patients with acute myocardial infarction (AMI). Before discharge, patients undergoing percutaneous coronary intervention (PCI) were randomly assigned to receive cilostazol SR capsule (200-mg) a day (n = 30) or placebo (n = 30) on top of dual antiplatelet therapy (DAPT) with clopidogrel and aspirin. Before randomization (baseline) and at 30-day follow-up, circulating EPC levels were analyzed using flow cytometry and hemostatic measurements were evaluated by VerifyNow and thromboelastography assays. The primary endpoint was the relative change in EPC levels between baseline and 30-day.

RESULTS

At baseline, there were similar levels of EPC counts between treatments, whereas patients with cilostazol showed higher levels of EPC counts compared with placebo after 30 days. Cilostazol versus placebo treatment displayed significantly higher changes in EPC levels between baseline and follow-up (ΔCD133+/KDR+: difference 216%, 95% confidence interval (CI) 44~388%, p = 0.015; ΔCD34+/KDR+: difference 183%, 95% CI 25~342%, p = 0.024). At 30-day follow-up, platelet reactivity was lower in the cilostazol group compared with the placebo group (130 ± 45 versus 169 ± 62 P2Y12 Reaction Unit, p = 0.009). However, there were no significant correlations between the changes of EPC levels and platelet reactivity.

CONCLUSION

Adjunctive cilostazol on top of clopidogrel and aspirin versus DAPT alone is associated with increased EPC mobilization and decreased platelet reactivity in AMI patients, suggesting its pleiotropic effects against atherothrombotic events (NCT04407312).

Association Between Residual Platelet Reactivity on Clopidogrel Treatment and Severity of Coronary Atherosclerosis: Intrinsic Hypercoagulability as a Mediator

INTRODUCTION

High on-treatment residual platelet reactivity (HRPR) was associated with greater atherosclerosis burden. We examined whether intrinsic hypercoagulability (IHC) could be attributed to that association in patients treated by drug-eluting stents.

METHODS

This retrospective observation enrolled a total of 891 coronary artery disease (CAD) subjects. Platelet and coagulant reactivity was measured by thrombelastography. At least 24 h after a 300-mg dose of clopidogrel, adenosine diphosphate (ADP)-induced maximum amplitude of clot strength (MA_adp) > 47 mm represented HRPR. Thrombin-induced platelet-fibrin clot strength (MA_thrombin) and blood fibrinogen surrogated intrinsic coagulability. Using mediation analysis to evaluate the effect of IHC on the relationship between the number of narrowed coronaries and HRPR on clopidogrel.

RESULTS

More HRPR on clopidogrel and higher intrinsic coagulability were observed in more severe coronary atherosclerosis, especially in the three-vessel disease. After adjustment for confounding factors, the number of narrowed coronaries (OR_adj = 1.343, 95% CI 1.063-1.695, p = 0.013), MA_thrombin (OR_adj = 1.106, 95% CI 1.058-1.157, p < 0.001), and fibrinogen (OR_adj = 1.003, 95% CI 1.001-1.005, p = 0.012) were all independent positive predictors for HRPR. MA_thrombin and fibrinogen were meaningful mediators for the significant positive association of the number of narrowed vessels and HRPR on clopidogrel, which were enhanced by around 30% and 43%, respectively, for this effect.

CONCLUSIONS

This is the first study to demonstrate that the positive correlation between the number of stenotic coronaries and HRPR on clopidogrel may be partly attributed to IHC, which may enhance the risk stratification, guide more precise coagulation in multi-vessel disease after drug-eluting stents, and therefore deserve further study.

Importance of Endogenous Fibrinolysis in Platelet Thrombus Formation

The processes of thrombosis and coagulation are finely regulated by endogenous fibrinolysis maintaining healthy equilibrium. When the balance is altered in favour of platelet activation and/or coagulation, or if endogenous fibrinolysis becomes less efficient, pathological thrombosis can occur. Arterial thrombosis remains a major cause of morbidity and mortality in the world despite advances in medical therapies. The role endogenous fibrinolysis in the pathogenesis of arterial thrombosis has gained increasing attention in recent years as it presents novel ways to prevent and treat existing diseases. In this review article, we discuss the role of endogenous fibrinolysis in platelet thrombus formation, methods of measurement of fibrinolytic activity, its role in predicting cardiovascular diseases and clinical outcomes and future directions.

Thrombin induced platelet-fibrin clot strength in relation to platelet volume indices and inflammatory markers in patients with coronary artery disease

Platelet aggregation and inflammation are both implicated in coronary artery disease (CAD). Thrombin induced platelet-fibrin clot strength (MA_Thrombin) measured by thrombelastography (TEG) has been proved to be a novel marker of platelet aggregation. The aim of this study was to investigate the correlation of MA_Thrombin to platelet volume indices (PVIs) or to inflammatory markers in different types of CAD. 206 patients with different types of CAD were enrolled. MA_Thrombin, PVIs, including mean platelet volume (MPV), platelet distribution width (PDW), and platelet-large cell ratio (P-LCR) as well as inflammatory markers, including high-sensitivity C-reactive protein (hs-CRP) and fibrinogen (Fbg) were measured. Multiple linear regression models were used to analyze the association between MA_Thrombin, PVIs, and inflammatory markers. MA_Thrombin and inflammatory markers both varied with CAD types (P<0.001). MA_Thrombin was correlated to PVIs in NSTEMI individuals (MPV, r=0.393, P=0.007; PDW, r=0.334, P=0.023; P-LCR, r=0.382, P=0.008), but had inner-link with inflammatory markers in STEMI cases (hs-CRP, r=0.499, P<0.001; Fbg, r=0.500, P<0.001). These findings may suggest different mechanisms of platelet aggregation in different types of CAD. Moreover, MA_Thrombin may be used as a potential parameter to evaluate platelet aggregation and inflammation together.

Central aortic pulse pressure, thrombogenicity and cardiovascular risk

High central aortic pulse pressure (CPP) and thrombin-induced platelet-fibrin clot strength (TIP-FCS) have been associated with ischemic outcomes in patients with coronary artery disease in separate studies. But, the ischemic risk associated with these factors has never been analyzed in a single study and their interrelation is unknown. The primary aim of the study was to establish cut points for CPP and TIP-FCS measured at the time of catheterization associated with long term major adverse cardiovascular events. We enrolled 334 consecutive patients undergoing cardiac catheterization and assessed thrombogenicity by thrombelastography. Patients were followed up to 3 years. The primary endpoint was a composite of cardiovascular death, myocardial infarction, and ischemic stroke and the secondary endpoint was occurrence of the primary endpoint or recurrent ischemic events requiring hospitalization. Patients with primary and secondary endpoint occurrence had higher CPP (83 ± 20 vs. 60 ± 18 mmHg, p < 0.0001; 70 ± 21 vs. 59 ± 18 mmHg, p < 0.0001, respectively) and TIP-FCS (68.5 ± 5.8 vs. 65.5 ± 5.0 mm, p = 0.008; 67.4 ± 5.9 vs. 65.2 ± 4.8 mm, p = 0.001, respectively). CPP >60 mmHg and TIP-FCS >69 mm were both independent predictors of primary endpoint occurrence (p = 0.0001 and p = 0.02, respectively). ROC analysis for CPP and TIP-FCS showed a C-statistic of 0.81 (p < 0.0001) and 0.68 (p = 0.007) for the primary endpoint, respectively. Patients with CPP >60 mmHg had higher TIP-FCS (66.8 ± 5.1 vs. 64.8 ± 5.0 mm, p < 0.001) and primary and secondary endpoint occurrence (13 vs. 1.1%, p < 0.0001 and 31.8 vs. 14.4%, p = 0.0002, respectively). CPP >60 mmHg + TIP-FCS > 69 mm was associated with a markedly increased risk of primary endpoint occurrence [HR (95% CI) 5.4(2.3-12.5), p = 0.0001]. High CPP and thrombogenicity are interrelated; each are independently associated with increased cardiovascular risk; and simultaneous presence markedly enhances risk. The mechanistic link between CPP and thrombogenicity deserves further study.

Pharmacodynamic effects of a new fixed-dose clopidogrel-aspirin combination compared with separate administration of clopidogrel and aspirin in patients treated with coronary stents: The ACCEL-COMBO trial

Dual antiplatelet therapy (DAPT) with clopidogrel and aspirin is a widely prescribed regimen to prevent ischemic events in patients undergoing percutaneous coronary intervention (PCI). A fixed-dose combination (FDC) capsule (HCP0911) has been developed to provide dosing convenience and improve adherence. We compared the antiplatelet effects of single daily dose HCP0911 with separate treatment with daily 75 mg clopidogrel plus 100 mg aspirin. This was a randomized, open-label, two-period, crossover, non-inferiority study conducted in stented patients who had been treated for at least 6 months with clopidogrel and aspirin. Thirty patients were randomly assigned to receive either daily 75 mg clopidogrel plus 100 mg aspirin treatment or HCP0911 for 2 weeks and then were crossed over to the other treatment for 2 weeks. Pharmacodynamic effects were measured with VerifyNow, light transmittance aggregometry (LTA), and thromboelastography (TEG®). The primary endpoint was P2Y12 Reaction Units (PRU) measured by VerifyNow. PRUs during treatment with HCP0911 were not inferior to those during separate treatment (202 ± 52 vs. 207 ± 60 PRU; mean difference, -5 PRU; 90% confidence interval of difference, -23 to 13 PRU; P for non-inferiority = 0.015 for predetermined limit). "BASE" and Aspirin Reaction Units by VerifyNow did not differ between the two treatments. During each treatment, there were no differences in maximal and final platelet aggregations by LTA (all P values ≥0.822) and TEG® measurements. In conclusion, in stented patients, the antiplatelet effect of a fixed-dose clopidogrel-aspirin combination, HCP0911, was not inferior to separate administration of clopidogrel and aspirin.

Point-of-Care Technologies for Precision Cardiovascular Care and Clinical Research: National Heart, Lung, and Blood Institute Working Group

Point-of-care technologies (POC or POCT) are enabling innovative cardiovascular diagnostics that promise to improve patient care across diverse clinical settings. The National Heart, Lung, and Blood Institute convened a working group to discuss POCT in cardiovascular medicine. The multidisciplinary working group, which included clinicians, scientists, engineers, device manufacturers, regulatory officials, and program staff, reviewed the state of the POCT field; discussed opportunities for POCT to improve cardiovascular care, realize the promise of precision medicine, and advance the clinical research enterprise; and identified barriers facing translation and integration of POCT with existing clinical systems. A POCT development roadmap emerged to guide multidisciplinary teams of biomarker scientists, technologists, health care providers, and clinical trialists as they: 1) formulate needs assessments; 2) define device design specifications; 3) develop component technologies and integrated systems; 4) perform iterative pilot testing; and 5) conduct rigorous prospective clinical testing to ensure that POCT solutions have substantial effects on cardiovascular care.

Endogenous Fibrinolysis: An Important Mediator of Thrombus Formation and Cardiovascular Risk

Most acute cardiovascular events are attributable to arterial thrombosis. Plaque rupture or erosion stimulates platelet activation, aggregation, and thrombosis, whilst simultaneously activating enzymatic processes that mediate endogenous fibrinolysis to physiologically maintain vessel patency. Interplay between these pathways determines clinical outcome. If proaggregatory factors predominate, the thrombus may propagate, leading to vessel occlusion. However, if balanced by a healthy fibrinolytic system, thrombosis may not occur or cause lasting occlusion. Despite abundant evidence for the fibrinolytic system regulating thrombosis, it has been overlooked compared with platelet reactivity, partly due to a lack of techniques to measure it. We evaluate evidence for endogenous fibrinolysis in arterial thrombosis and review techniques to assess it, including biomarkers and global assays, such as thromboelastography and the Global Thrombosis Test. Global assays, simultaneously assessing proaggregatory and fibrinolytic pathways, could play a role in risk stratification and in identifying impaired fibrinolysis as a potential target for pharmacological modulation.

Impact of tailored anti-P2Y12 therapies in acute coronary syndromes

Acute coronary syndromes are a major disease burden and the prognosis has improved over the last decades due to improvement of medical and interventional treatments. Novel P2Y12-ADP-receptor antagonists have been introduced into clinical treatment offering more potent and rapid onset of action with the downside of increased bleeding risk. This special report will focus on interindividual variability of antiplatelet drugs in the setting of acute coronary syndromes and the current impact and potential future of point-of-care testing to personalize therapy aiming to improve prognosis in acute coronary syndrome patients.