Platelets after intracerebral haemorrhage: more is not better

Platelet Transfusion: An Update on Indications and Guidelines

Platelets are commonly transfused either therapeutically or prophylactically to maintain hemostasis. Most platelet transfusions are used to manage patients with hematologic malignancies. Although platelet transfusion guidelines have been published, platelet transfusion practices are still heterogeneous. Platelet transfusion guidelines partly lack recommendations or differ in the platelet threshold recommendations in some clinical situations. This article reviews platelet transfusions focusing on transfusion guidelines and platelet thresholds in different clinical settings.

Hemorrhagic stroke

Hemorrhagic stroke comprises about 20% of all strokes, with intracerebral hemorrhage (ICH) being the most common type. Frequency of ICH is increased where hypertension is untreated. ICH in particularly has a disproportionately high risk of early mortality and long-term disability. Until recently, there has been a paucity of randomized controlled trials (RCTs) to provide evidence for the efficacy of various commonly considered interventions in ICH, including acute blood pressure management, coagulopathy reversal, and surgical hematoma evacuation. Evidence-based guidelines do exist for ICH and these form the basis for a framework of care. Current approaches emphasize control of extremely high blood pressure in the acute phase, rapid reversal of vitamin K antagonists, and surgical evacuation of cerebellar hemorrhage. Lingering questions, many of which are the topic of ongoing clinical research, include optimizing individual blood pressure targets, reversal strategies for newer anticoagulant medications, and the role of minimally invasive surgery. Risk stratification models exist, which derive from findings on clinical exam and neuroimaging, but care should be taken to avoid a self-fulfilling prophecy of poor outcome from limiting treatment due to a presumed poor prognosis. Cerebral venous thrombosis is an additional subtype of hemorrhagic stroke that has a unique set of causes, natural history, and treatment and is discussed as well.

Hematoma Expansion in Intracerebral Hemorrhage: An Update on Prediction and Treatment

Intracerebral hemorrhage (ICH) is the most lethal type of stroke, but there is no specific treatment. After years of effort, neurologists have found that hematoma expansion (HE) is a vital predictor of poor prognosis in ICH patients, with a not uncommon incidence ranging widely from 13 to 38%. Herein, the progress of studies on HE after ICH in recent years is updated, and the topics of definition, prevalence, risk factors, prediction score models, mechanisms, treatment, and prospects of HE are covered in this review. The risk factors and prediction score models, including clinical, imaging, and laboratory characteristics, are elaborated in detail, but limited by sensitivity, specificity, and inconvenience to clinical practice. The management of HE is also discussed from bench work to bed practice. However, the upmost problem at present is that there is no treatment for HE proven to definitely improve clinical outcomes. Further studies are needed to identify more accurate predictors and effective treatment to reduce HE.

PATCHing platelet data to improve transfusion

The Platelet Transfusion in Cerebral Hemorrhage (PATCH) trial, a trial of platelet transfusion in patients on antiplatelet agents with cerebral hemorrhage, suggested that platelets worsened outcomes. Reanalysis of the data by the investigators revealed that despite randomization, some, if not all, of the adverse effects of platelets reflected worse baseline hemorrhage in patients in the platelet arm.

Laboratory Monitoring of Platelet P2Y12 Receptor Inhibitors and Reversal of Antiplatelet Agents

OBJECTIVES

To review the use of laboratory tests for antiplatelet agents to determine escalation of antiplatelet therapy and for emergent reversal of P2Y12 inhibitors.

METHODS

A case scenario and review of cardiovascular and neurointerventional literature are described.

RESULTS

In cardiovascular disease patients, large randomized trials failed to demonstrate superiority of tailored antiplatelet regimens using the VerifyNow P2Y12 assay, where earlier studies had shown promise. Platelet transfusions restored platelet function measured by vasodilator-stimulated phosphoprotein, light transmission aggregometry, or thromboelastography but not VerifyNow P2Y12, with the most restoration for clopidogrel and the least for ticagrelor.

CONCLUSIONS

Current evidence does not support changing antiplatelet therapy based on the results of platelet function monitoring tests. For emergent reversal of P2Y12 inhibitors, test method can affect platelet dosing recommendations, as different methods may give different results.