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Background High-sensitivity C-reactive protein (hs-CRP) has been proposed as an indicator of inflammation and cardiovascular risk. However, little is known of the comparative temporal profile of hs-CRP and its relation to outcomes according to the disease acuity. Methods We enrolled 4,263 East Asian patients who underwent percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) and stable disease. hs-CRP was measured at baseline and 1 month post-PCI. Major adverse cardiovascular events (MACE: the composite occurrence of death, myocardial infarction, or stroke) and major bleeding were followed up to 4 years. Result The AMI group (n = 2,376; 55.7%) had higher hs-CRPbaseline than the non-AMI group (n = 1,887; 44.3%) (median: 1.5 vs. 1.0 mg/L; p Conclusion AMI patients have greater inflammation during the early and late phases than non-AMI patients. Risk phenotype of hs-CRPbaseline correlates with 1-month outcomes only in AMI patients. However, the prognostic implications of this risk phenotype appears similar during the late phase, irrespective of the disease acuity.

Background Direct-acting oral anticoagulants (DOACs) do not require monitoring. Measurement of DOAC effect would be useful in the event of bleeding, trauma, and thromboembolism while on anticoagulation. We evaluated the effectiveness of the investigational DOAC assays on the TEG®6s Hemostasis Analyzer to assess the anticoagulant effect of DOACs in patients treated for atrial fibrillation or deep vein thrombosis (DVT). Methods Patients on treatment for a minimum of 7 days with standard doses of dabigatran, rivaroxaban, and apixaban were included. DOAC plasma concentrations and TEG®6s Reaction (R)-time were measured and correlated. The sensitivity, specificity, and negative predictive value (NPV) of R-time to detect DOAC concentrations of ≥30, ≥50, and ≥100 ng/mL were calculated. Results A total of 189 patients were included, (n = 50) on apixaban, (n = 62) on rivaroxaban, (n = 53) on dabigatran, and (n = 24) on no DOAC were studied. Using the direct thrombin inhibitor (DTI) channel, R-time demonstrated strong linear correlation with dabigatran levels (r = 0.93, p Conclusion R-time measured by TEG®6s DOAC-specific cartridge has a strong correlation with concentrations of the most commonly used DOACs with high sensitivity and NPV for detecting lower drug levels that are considered clinically relevant for patients in need of antidote, or prior to urgent surgery. Further studies to determine the relation of R-time to clinical outcomes are warranted.

Amlodipine has a potential to reduce clopidogrel bioactivation through the cytochrome P450 3A4 enzyme in vivo, but the clinical impact of this interaction remains controversial. This randomized, open-label, two-period, crossover study was performed to evaluate the influence of amlodipine on the haemostatic profiles of high-risk patients during clopidogrel treatment. We recruited 40 Asian patients (Male/Female: n = 36/4) receiving clopidogrel (75 mg/day), aspirin (100 mg/day) and rosuvastatin for at least 6 months following percutaneous coronary intervention. Patients were randomly assigned to receive either 5 mg daily amlodipine or not for 2 weeks, and then were crossed over to the other treatment for 2 weeks. Haemostatic measurements were conducted with the VerifyNow assay and thromboelastography (TEG). Primary endpoint was P2Y12 Reaction Units (PRU) during on- versus off-amlodipine treatment. The on-amlodipine strategy showed higher level of PRU compared with the off-amlodipine strategy (176.8 ± 75.4 vs. 150.7 ± 65.5 PRU; ∆mean: 26.1 PRU; ∆95% confidence interval [CI]: 4.5–47.7 PRU; p = 0.019). Platelet-fibrin clot strength measured by TEG was lower during on- versus off-amlodipine treatment (7,712 ± 1,889 vs. 8,559 ± 2,174 dyne/cm2; ∆mean: –847 dyne/cm2; ∆95% CI: –1,632 to –62 dyne/cm2; p = 0.035). After amlodipine discontinuation, 27 patients (67.5%) showed a decrease in PRU, which was associated with ‘PRU ≥ 160 on-amlodipine’ in multivariate analysis (odds ratio: 62.014; 95% CI: 2.302–1670.328; p = 0.014). In conclusion, amlodipine increases platelet reactivity and decreases platelet-fibrin clot strength during clopidogrel treatment. In addition, the effect of amlodipine discontinuation on clopidogrel responsiveness is associated with on-amlodipine platelet reactivity.

Platelet activation and aggregation play a pivotal role in thrombotic complications occurring during percutaneous coronary intervention (PCI), and peri-PCI anti-platelet therapy represents a standard of care. High platelet reactivity prior to PCI has been correlated with an increased incidence of peri-procedural myonecrosis. Pre-PCI platelet reactivity predicts post-PCI platelet reactivity and has a prognostic impact on subsequent ischaemic and bleeding events, so as the platelet inhibition measured post-PCI. Many anti-platelet treatment strategies, including aspirin, glycoprotein IIb/IIIa inhibitors, P2Y12 receptor blockers and vorapaxar, are being used in the routine clinical practice to modify platelet reactivity at each stage, e.g. pre-, during and post-PCI. Anti-platelet strategies with a ‘stronger and faster’ pharmacodynamic effect than clopidogrel have been mostly adopted in patients with acute coronary syndromes. However, several issues regarding the anti-platelet treatment such as benefits/risks of anti-platelet therapy pre-treatment and duration, and definite association between speed and potency of various anti-platelet agents and clinical outcomes remain controversial. We believe that a better understanding of peri-PCI platelet reactivity and its relations to outcomes may lead to the development of more effective and safe treatment strategies.

SummaryThe role of platelet-leukocyte interaction in the infarct myocardium still remains unveiled. We aimed to determine the linkage of platelet activation to post-infarct left ventricular remodelling (LVR) process. REMODELING was a prospective, observational, cohort trial including patients (n = 150) with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention. Patients were given aspirin plus clopidogrel therapy (600 mg loading and 75 mg daily). Platelet reactivity (PRU: P2Y12 Reaction Units) was assessed with VerifyNow P2Y12 assay on admission. Transthoracic echocardiography was performed on admission and at one-month follow-up. The primary endpoint was the incidence of LVR according to PRU-based quartile distribution. LVR was defined as a relative ≥ 20 % increase in LV end-diastolic volume (LVEDV) between measurements. Adverse LVR was observed in 36 patients (24.0 %). According to PRU quartile, LVR rate was 10.8 % in the first, 23.1 % in the second, 27.0 % in the third, and 35.1 % in the fourth (p = 0.015): the optimal cut-off of PRU was ≥ 248 (area under curve: 0.643; 95 % confidence interval: 0.543 to 0.744; p = 0.010). LVR rate also increased proportionally according to the level of high sensitivity-C reactive protein (hs-CRP) (p = 0.012). In multivariate analysis, the combination of PRU (≥ 248) and hs-CRP (≥ 1.4 mg/l) significantly increased the predictive value for LVR occurrence by about 21-fold. In conclusion, enhanced levels of platelet activation and inflammation determined the incidence of adverse LVR after STEMI. Combining the measurements of these risk factors increased risk discrimination of LVR. The role of intensified antiplatelet or anti-inflammatory therapy in post-infarct LVR process deserves further study.

Unravelling the Smokers’ Paradox: Cigarette smoking, high-risk coronary artery disease and enhanced clinical efficacy of oral P2Y12 inhibitors

SummaryThe relationship between thrombin-induced platelet-fibrin clot strength (MATHROMBIN), genotype and high on-treatment platelet reactivity (HPR) is unknown. The aim of this study is to assess the influence of MATHROMBIN measured by thrombelastography on HPR and long-term major adverse cardiovascular events (MACE) in percutaneous coronary intervention (PCI)-treated patients during aspirin and clopidogrel therapy. MATHROMBIN, platelet aggregation, genotype, and two-year MACE were assessed in 197 PCI-treated patients. HPR was defined as 5 µM ADP-induced PR46% measured by conventional aggregometry. Both high MATHROMBIN ( 68 mm) and CYP2C19*2 allele carriage were independently associated with ADP-induced platelet aggregation ([uni03B2] coefficient: 8.3% and 12.0%, respectively). The combination of CYP2C19*2 allele carriage and high MATHROMBIN increased the predictive value for the risk of HPR (odds ratio: 13.89; 95% confidence interval: 3.41 to 55.56; p < 0.001). MACE occurred in 25 patients (12.7%). HPR and high MATHROMBIN were both associated with MACE (hazard ratio: 3.09 and 2.24, respectively), and patients with both HPR and high MATHROMBIN showed an increased risk for MACE (adjusted hazard ratio: 5.56; 95% confidence interval: 1.85 to 16.67; p = 0.002). In conclusion, this is the first study to demonstrate that high platelet-fibrin clot strength is an independent determinant of HPR in PCI-treated patients. Combining the measurements of platelet aggregation and platelet-fibrin clot strength may enhance post-PCI risk stratification and deserves further study.

SummaryPercutaneous coronary intervention (PCI) has significantly improved clinical outcomes in coronary artery disease patients. Since PCI is associated with platelet activation, antiplatelet therapy with aspirin, clopidogrel and GPIIb/IIIa inhibitors comprise the cornerstone strategy during and following PCI. The latter agents are arguably the most important drugs we administer to the patient with established coronary artery disease since they are specifically given to prevent the most catastrophic event, the formation of an occlusive arterial thrombus. Numerous clinical trials have confirmed the efficacy of antiplatelet therapy in attenuating recurrent ischaemic event occur-rence.Despite the extensive use of antiplatelet therapies, ischaemic event occurrence such as post-procedural myocardial infarction and stent thrombosis still remains an important concern and highlights the need for improved treatment strategies. A major limitation of current treatment is the application of a “one size fits all” strategy advocated by the guidelines that completely ignores the evaluation of the individual antiplatelet response. Pharmacodynamic studies have revealed the limitations of aspirin and clopidogrel treatment that include response variability, and a high prevalence of antiplatelet non-responsiveness associated with significant risk for recurrent ischemic event occurrence. Thus, two major paradoxes in cardiovascular medicine today are: 1) despite the overwhelming evidence that platelet reactivity strongly influences the development of potentially catastrophic events including myocardial infarction and stent thrombosis in the PCI patient, no measurement is made in clinical practice to assess the presence of blood vulnerability (platelet reactivity) and 2) despite the overwhelming evidence that the effect of dual antiplatelet therapy with aspirin and P2Y12 receptor blockers is variable, the guidelines largely recommend a uniform, “one size fits all” dosing of these agents in the PCI patient without any confirmation of an adequate antiplatelet effect.