Antiplatelet Resistance—Does it Exist and How to Measure it?

Aspirin and clopidogrel are the most commonly used antiplatelet agents in patients with coronary artery disease. The existence of resistance to these agents has been a controversial issue and new drugs are being developed to overcome this problem. Laboratory tests, which can identify resistance and correlate this with clinical outcome, are being studied in order to identify patients at risk of future thrombotic events. We discuss the evidence for the existence of antiplatelet resistance—both in the laboratory and in the clinical setting. So far, platelet aggregometry has been considered the gold standard test, but is very operator dependant, time consuming, and has shown little correlation with other available tests of antiplatelet resistance. We discuss the available tests of platelet function, their limitations, and evidence for their use. A simple, rapid, near-patient test, which is affordable and useful in the clinical (not just laboratory) setting, could allow risk stratification of patients and individualization of antiplatelet medication to improve outcome

Prevention of stroke in patients with chronic coronary syndromes or peripheral arterial disease

Stroke is a common and devastating condition caused by atherothrombosis, thromboembolism, or haemorrhage. Patients with chronic coronary syndromes (CCS) or peripheral artery disease (PAD) are at increased risk of stroke because of shared pathophysiological mechanisms and risk-factor profiles. A range of pharmacological and non-pharmacological strategies can help to reduce stroke risk in these groups. Antithrombotic therapy reduces the risk of major adverse cardiovascular events, including ischaemic stroke, but increases the incidence of haemorrhagic stroke. Nevertheless, the net clinical benefits mean antithrombotic therapy is recommended in those with CCS or symptomatic PAD. Whilst single antiplatelet therapy is recommended as chronic treatment, dual antiplatelet therapy should be considered for those with CCS with prior myocardial infarction at high ischaemic but low bleeding risk. Similarly, dual antithrombotic therapy with aspirin and very-low-dose rivaroxaban is an alternative in CCS, as well as in symptomatic PAD. Full-dose anticoagulation should always be considered in those with CCS/PAD and atrial fibrillation. Unless ischaemic risk is particularly high, antiplatelet therapy should not generally be added to full-dose anticoagulation. Optimization of blood pressure, low-density lipoprotein levels, glycaemic control, and lifestyle characteristics may also reduce stroke risk. Overall, a multifaceted approach is essential to best prevent stroke in patients with CCS/PAD

Shear-induced global thrombosis test of native blood: Pivotal role of ADP allows monitoring of P2Y12 antagonist therapy

Original article can be found at: http://www.sciencedirect.com/science/journal/00493848 Copyright Elsevier Ireland Ltd. [Full text of this article is not available in the UHRA]Background: It is claimed that in shear-induced platelet function tests, shear-stress is the sole agonist causing platelet activation and resultant thrombosis. However, the fact that red blood cells (RBC) are essential to achieve platelet aggregation in these tests supports recent evidence that ADP makes an important contribution to shear-induced platelet reaction. Aim: To establish the role of ADP in shear-induced thrombosis, and investigate whether a shear-induced thrombosis test can assess ADP-receptor (P2Y12) antagonist medication. Methods: Blood from healthy volunteers was tested using the Global Thrombosis Test (GTT), before and after clopidogrel. To investigate the importance of contact of blood with plastic, the reactive part of the tube was primed with saline. We also investigated the effect of priming the tube with water, to cause localised haemolysis and ADP release. Results: Saline-priming prolonged occlusion times (OT) by 25% (p < 0.01) confirming ADP release from platelets and RBC as a result of contact. Water-priming shortened OT, accelerating the thrombotic reaction (accelerated GTT; aGTT) (OT 379 vs. 177s, p < 0.01). Clopidogrel increased OT (379 vs. 477s, p < 0.01), preventing the shortening of aGTT-OT (177 vs. 362s, pre- and post-clopidogrel; p < 0.01). Conclusion: In addition to thrombin formation, ADP released from platelets and RBC in native blood subjected to high shear-stress makes an important contribution to the resultant thrombotic occlusion. The described aGTT sensitively detected the effect of clopidogrel and thus seems suitable for monitoring and individualizing ADP-receptor antagonist therapy. Parallel measurement of GTT and aGTT would allow assessment of both global thrombotic status and response to P2Y12 antagonist therapy.Peer reviewe

Multicenter randomized trial of intermittently scanned continuous glucose monitoring versus self-monitoring of blood glucose in individuals with type 2 diabetes and recent-onset acute myocardial infarction: results of the LIBERATES trial

OBJECTIVE To analyze the impact of modern glucose-monitoring strategies on glycemic and patient-related outcomes in individuals with type 2 diabetes (T2D) and recent myocardial infarction (MI) and assess cost effectiveness. RESEARCH DESIGN AND METHODS LIBERATES was a multicenter two-arm randomized trial comparing self-monitoring of blood glucose (SMBG) with intermittently scanned continuous glucose monitoring (isCGM), also known as flash CGM, in individuals with T2D and recent MI, treated with insulin and/or a sulphonylurea before hospital admission. The primary outcome measure was time in range (TIR) (glucose 3.9–10 mmol/L/day) on days 76–90 post randomization. Secondary and exploratory outcomes included time in hypoglycemia, hemoglobin A1c (HbA1c), clinical outcome, quality of life (QOL), and cost effectiveness. RESULTS Of 141 participants randomly assigned (median age 63 years; interquartile range 53, 70), 73% of whom were men, isCGM was associated with increased TIR by 17 min/day (95% credible interval −105 to +153 min/day), with 59% probability of benefit. Users of isCGM showed lower hypoglycemic exposure (<3.9 mmol/L) at days 76–90 (−80 min/day; 95% CI −118, −43), also evident at days 16–30 (−28 min/day; 95% CI −92, 2). Compared with baseline, HbA1c showed similar reductions of 7 mmol/mol at 3 months in both study arms. Combined glycemic emergencies and mortality occurred in four isCGM and seven SMBG study participants. QOL measures marginally favored isCGM, and the intervention proved to be cost effective. CONCLUSIONS Compared with SMBG, isCGM in T2D individuals with MI marginally increases TIR and significantly reduces hypoglycemic exposure while equally improving HbA1c, explaining its cost effectiveness. Studies are required to understand whether these glycemic differences translate into longer-term clinical benefit

Management of antithrombotic therapy in patients undergoing transcatheter aortic valve implantation: a consensus document of the ESC Working Group on Thrombosis and the European Association of Percutaneous Cardiovascular Interventions (EAPCI), in collaboration with the ESC Council on Valvular Heart Disease

Transcatheter aortic valve implantation (TAVI) is effective in older patients with symptomatic severe aortic stenosis, while the indication has recently broadened to younger patients at lower risk. Although thromboembolic and bleeding complications after TAVI have decreased over time, such adverse events are still common. The recommendations of the latest 2017 ESC/EACTS Guidelines for the management of valvular heart disease on antithrombotic therapy in patients undergoing TAVI are mostly based on expert opinion. Based on recent studies and randomized controlled trials, this viewpoint document provides updated therapeutic insights in antithrombotic treatment during and after TAVI.[GRAPHICS]