Platelet function recovery following exposure to triple anti-platelet inhibitors using an in vitro transfusion model

Coagulopathy and Emergent Reversal of Anticoagulation

More patients than ever are presenting for urgent or emergent procedures while therapeutically anticoagulated for various medical indications. Medications including warfarin, antiplatelet agents such as clopidogrel, direct oral anticoagulants such as apixaban, and even heparin or heparinoids may be present. Each of these medication classes presents its own challenges when coagulopathy needs to be quickly corrected. This review article presents evidence-based discussions of monitoring and reversal of these medication-induced coagulopathies. In addition, there will be a brief discussion of other potential coagulopathies that may be encountered in providing acute care anesthesia.

Emergency Reversal of Anticoagulation

Owing to the propensity of anticoagulated patients to bleed, a strategy for reversal of anticoagulation induced by any of the common agents is essential. Many patients are anticoagulated with a variety of agents, including warfarin, low molecular weight heparin, and the direct oral anticoagulants such as factor Xa and factor IIa inhibitors. Patients may also be using antiplatelet agents. Recommendations to reverse bleeding in these patients are constantly evolving with the recent development of specific reversal agents. A working knowledge of hemostasis and the reversal of anticoagulation and antiplatelet drugs is required for every emergency department provider. This article reviews these topics and presents the currently recommended strategies for dealing with bleeding in the anticoagulated patient.

In vitro properties of concentrated canine platelets stored in two additive solutions: a comparative study

BACKGROUND

Platelet transfusion therapy poses many challenges in veterinary clinical practice. Lack of readily available blood donors, short shelf-life, and inability to administer a sufficient number of platelets to meet a dog's transfusion need are the major difficulties encountered. Platelet additive solutions are already in use at American and European human blood banks, showing to be a realistic alternative. This study compares the in vitro platelet function in plasma, Composol, or SSP+ during storage for 13 days. Platelet rich plasma-platelet concentrate with 35% plasma and 65% platelet additive solutions (Composol or SSP+) and a control group (100% plasma) were prepared. Swirling, platelet count, blood gases, metabolic variables, platelet activation markers, and apoptosis markers were analyzed on days 1, 5, 9 and 13.

RESULTS

Swirling was well preserved and pH was acceptable (> 6.2) during storage for all platelet additive solutions units until day 9. SSP + units showed more stable pH and metabolic variables until day 13. Platelets in plasma showed higher glucose consumption than in Composol or in SSP+. The platelet additive solutions units showed better platelet metabolism maintenance, reduced glucose consumption and lactate production. The apoptotic markers were still low for 9 days in platelet concentrates with platelet additive solutions, suggesting the possibility to extend the shelf life with the use of SSP+ or Composol.

CONCLUSIONS

Our findings suggest that the uses of Composol and SSP+ in canine platelet concentrates are potential alternatives in veterinary blood banks.

Pharmacokinetic drug evaluation of vorapaxar for secondary prevention after acute coronary syndrome

INTRODUCTION

Vorapaxar is the first protease-activated receptor-1 inhibitor approved for clinical use. Its main indication is the reduction in thrombotic cardiovascular events in patients with previous myocardial infarction or symptomatic peripheral artery disease. Areas covered: This article reviews the pharmacokinetics of vorapaxar and its potential use in secondary prevention after an acute coronary syndrome. Expert opinion: Vorapaxar inhibits platelet aggregation mediated by thrombin. This effect is carried out without affecting to coagulation parameters and bleeding times. This drug has showed a significant reduction of cardiovascular events in patients with chronic atherosclerosis but not during the admission for an acute coronary syndrome. The rate of major bleeding found in patients treated with vorapaxar in randomized trials was consistently higher than placebo in most of the analyzed subgroups. For this reason, cautious evaluation of risk-benefit profiles should be required before prescribing this drug.

High prevalence of pharmacologically induced platelet dysfunction in the acute setting of brain injury

BACKGROUND

The management of patients with traumatic brain injury (TBI), primary intracerebral hemorrhage (pICH) and primary subarachnoid hemorrhage (pSAH) remains a highly demanding challenge in critical care medicine. Antithrombotic agents are one of the most relevant risk factors for poor outcome. However, in the acute setting of brain injury, information on preexisting medication might not be available. This group of patients is insufficiently characterized regarding pharmacologically induced platelet impairment.

METHODS

We retrospectively analyzed consecutive patients with TBI, pICH and pSAH admitted to our department with unknown preexisting medication. The impact of acetylsalicylic acid and ADP-receptor antagonists on platelet function was tested via the Multiplate analyzer. Patients' characteristics, management and the influence of platelet impairment on outcome were evaluated.

RESULTS

Within 25 months 103 patients with TBI (61), pICH (32) or pSAH (10) and unknown antithrombotic medication were admitted to our department. In 54 (52.4 %) of the patients reduced platelet function was detected, mainly caused by acetylsalicylic acid. In the TBI group, 30 patients (49.2 %) were identified, while Multiplate analysis detected platelet dysfunction in 19 (59.4 %) subjects in the pICH group and 5 in the pSAH group (50 %). In multivariable analysis the pathological Multiplate result was not associated with worse outcome; however, in our cohort 47 (87 %) patients received hemostatic therapy following detection of impaired platelet function.

CONCLUSION

Our results demonstrate the high frequency of pharmacologically impaired platelet function in patients with unknown preexisting medication. Early assessment of platelet function is an important tool to allow optimized treatment in these patients.