Early Antiplatelet Resumption and the Risks of Major Bleeding After Intracerebral Hemorrhage

Stroke

Stroke affects up to one in five people during their lifetime in some high-income countries, and up to almost one in two in low-income countries. Globally, it is the second leading cause of death. Clinically, the disease is characterised by sudden neurological deficits. Vascular aetiologies contribute to the most common causes of ischaemic stroke, including large artery disease, cardioembolism, and small vessel disease. Small vessel disease is also the most frequent cause of intracerebral haemorrhage, followed by macrovascular causes. For acute ischaemic stroke, multimodal CT or MRI reveal infarct core, ischaemic penumbra, and site of vascular occlusion. For intracerebral haemorrhage, neuroimaging identifies early radiological markers of haematoma expansion and probable underlying cause. For intravenous thrombolysis in ischaemic stroke, tenecteplase is now a safe and effective alternative to alteplase. In patients with strokes caused by large vessel occlusion, the indications for endovascular thrombectomy have been extended to include larger core infarcts and basilar artery occlusion, and the treatment time window has increased to up to 24 h from stroke onset. Regarding intracerebral haemorrhage, prompt delivery of bundled care consisting of immediate anticoagulation reversal, simultaneous blood pressure lowering, and prespecified stroke unit protocols can improve clinical outcomes. Guided by underlying stroke mechanisms, secondary prevention encompasses pharmacological, vascular, or endovascular interventions and lifestyle modifications.

WY-14643, a novel antiplatelet and antithrombotic agent targeting the GPIbα receptor

BACKGROUND AND PURPOSE

Hypolipidemia and platelet activation play key roles in atherosclerotic diseases. Pirinixic acid (WY-14643) was originally developed as a lipid-lowering drug. Here we focused on its antiplatelet and antithrombotic abilities and the underlying mechanism.

EXPERIMENTAL APPROACH

The effects of WY-14643 on platelet aggregation was measured using a lumi-aggregometer. Clot retraction and spreading on fibrinogen were also assayed. PPARα-/- platelets were used to identify the target of WY-14643. The interaction between WY-14643 and glycoprotein Ibα (GPIbα) was detected using cellular thermal shift assay (CETSA), surface plasmon resonance (SPR) spectroscopy and molecular docking. GPIbα downstream signaling was examined by Western blot. The antithrombotic effect was investigated using mouse mesenteric arteriole thrombosis model. Mouse tail bleeding model was used to study its effect on bleeding side effects.

KEY RESULTS

WY-14643 concentration-dependently inhibits human washed platelet aggregation, clot retraction, and spreading. Significantly, WY-14643 inhibits thrombin-induced activation of human washed platelets with an IC50 of 7.026 μM. The antiplatelet effect of WY-14643 is mainly dependent of GPIbα. CESTA, SPR and molecular docking results indicate that WY-14643 directly interacts with GPIbα and acts as a GPIbα antagonist. WY-14643 also inhibits phosphorylation of PLCγ2, Akt, p38, and Erk1/2 induced by thrombin. Noteworthily, 20 mg/kg oral administration of WY-14643 inhibits FeCl3-induced thrombosis of mesenteric arteries in mice similarly to clopidogrel without increasing bleeding.

CONCLUSION AND IMPLICATIONS

WY-14643 is not only a PPARα agonist with lipid-lowering effect, but also an antiplatelet agent as a GPIbα antagonist. It may have more significant therapeutic advantages than current antiplatelet agents for the treatment of atherosclerotic thrombosis, which have lipid-lowering effects without bleeding side effects.

Antiplatelet Agent Use After Stroke due to Intracerebral Hemorrhage

This focused update about antiplatelet agents to reduce the high risk of major adverse cardiovascular events after stroke due to spontaneous (nontraumatic) intracerebral hemorrhage (ICH) complements earlier updates about blood pressure-lowering, lipid-lowering, and oral anticoagulation or left atrial appendage occlusion for atrial fibrillation after ICH. When used for secondary prevention in people without ICH, antiplatelet agents reduce the risk of major adverse cardiovascular event (rate ratio, 0.81 [95% CI, 0.75-0.87]) and might increase the risk of ICH (rate ratio, 1.67 [95% CI, 0.97-2.90]). Before 2019, guidance for clinical decisions about antiplatelet agent use after ICH has focused on estimating patients' predicted absolute risks and severities of ischemic and hemorrhagic major adverse cardiovascular event and applying the known effects of these drugs in people without ICH to estimate whether individual ICH survivors in clinical practice might be helped or harmed by antiplatelet agents. In 2019, the main results of the RESTART (Restart or Stop Antithrombotics Randomized Trial) randomized controlled trial including 537 survivors of ICH associated with antithrombotic drug use showed, counterintuitively, that antiplatelet agents might not increase the risk of recurrent ICH compared to antiplatelet agent avoidance over 2 years of follow-up (12/268 [4%] versus 23/268 [9%]; adjusted hazard ratio, 0.51 [95% CI, 0.25-1.03]; P=0.060). Guidelines in the United States, Canada, China, and the United Kingdom and Ireland have classified the level of evidence as B and indicated that antiplatelet agents may be considered/reasonable after ICH associated with antithrombotic agent use. Three subsequent clinical trials have recruited another 174 participants with ICH, but they will not be sufficient to determine the effects of antiplatelet therapy on all major adverse cardiovascular events reliably when pooled with RESTART. Therefore, ASPIRING (Antiplatelet Secondary Prevention International Randomized Study After Intracerebral Hemorrhage) aims to recruit 4148 ICH survivors to determine the effects of antiplatelet agents after ICH definitively overall and in subgroups.

Does dual antiplatelet therapy increase the risk of haematoma enlargement in the acute stage? A retrospective study of the use of stent-assisted coiling versus coiling alone or balloon-assisted coiling for the treatment of ruptured intracranial aneurysms combined with intracranial haematoma

This study aims to identify the efficacy and safety of stent-assisted coiling (SAC) treatment of ruptured intracranial aneurysms (RIAs) combined with intracranial haematoma (ICH) compared to coiling alone or balloon-assisted coiling (non-SAC). A retrospective analysis of 54 consecutive patients receiving endovascular therapy from 2014 to 2020 was performed. The data collected included baseline characteristics, angiographic results, perioperative complications, immediate aneurysm occlusion, clinical outcomes, follow-up at discharge and after 6 months, hospitalisation costs, and inpatient length of stay. Patients were categorised into the SAC group and the non-SAC group. Univariate and multivariate logistic regression analyses were used to identify risk factors related to clinical outcomes. Of the 54 patients harbouring RIAs with ICH, 22 (40.74%) and 32 (59.26%) patients were subject to SAC and non-SAC treatments, respectively. Postoperative rebleeding (1 [4.5%] and 3 [9.3%] in SAC and non-SAC groups, respectively, p > 0.05) and Hunt-Hess grade (IV-V) lesions (13.6% vs. 40.6%, p = 0.067) did not differ between the two groups. In total, 10 (45.5%) patients treated with SAC received a Fisher scale score of 0-3 compared with 6 (18.8%) patients treated with non-SAC methods (p = 0.035). Compared with the non-SAC group (7/21.9%), the rate of wide-necked aneurysms was increased in the SAC group (11/50%) (p = 0.031). No differences in poor outcomes (mRS > 2) were noted between the SAC and non-SAC groups (p > 0.05). Multivariate analysis revealed that ischaemic complication events (p = 0.016) represent the only independent risk factor for adverse outcomes, and a trend towards unfavourable clinical outcomes was noted for patients who smoke (p = 0.087). SAC is a safe and efficient treatment for RIAs combined with ICH when dual antiplatelet therapy (DAPT) is used in the perioperative period. In addition, SAC should be preferentially used in wide-neck RIAs. Ischaemic complications are a risk factor for poor clinical outcomes. Given the small sample size and retrospective bias of this study, these findings should be further verified in a study with a larger sample size or a randomised controlled trial (RCT).