Benefits and risks of P2Y12 inhibitor preloading in patients with acute coronary syndrome and stable angina

Center Variation in Use of Preoperative Dual Antiplatelet Therapy and Platelet Function Testing at the Time of Coronary Artery Bypass Grafting in Maryland

BACKGROUND

Patients presenting with acute coronary syndrome are administered a P2Y12 inhibitor and aspirin before coronary catheterization to prevent further myocardial injury from thrombosis. Guidelines recommend a standard waiting period between the time patients are administered dual antiplatelet therapy (DAPT) and elective cardiac surgery. Since 25% to 30% of the population may be considered nonresponders to clopidogrel, platelet function testing can be utilized for timing of surgery and to assess bleeding risks. The extent to which a standard waiting period or platelet function testing is used across centers is not established, representing an important opportunity to standardize practice.

METHODS

We conducted a retrospective cohort study from 2011 to 2020 using data from the Maryland Cardiac Surgical Quality Initiative, a consortium of all 10 hospitals in the state performing cardiac surgery. The proportion of patients administered DAPT within 5 days of surgery was examined by hospital over the time period. Mixed-effects multivariable logistic regressions were used to examine the association of preoperative DAPT with ischemic and bleeding outcomes. Centers were surveyed on use or nonuse of preoperative platelet function testing, and bleeding outcomes were compared.

RESULTS

There was significant heterogeneity of preoperative DAPT usage across centers ranging from 2% to 54% (P < .001). DAPT within 5 days of isolated coronary artery bypass grafting (CABG) was associated with higher odds of reoperation for bleeding (odds ratio [OR], 1.55; 95% confidence interval [CI], 1.19-2.01; P = .001), >2 units of red blood cells (RBCs) transfused (OR, 1.62; 95% CI, 1.44-1.81; P < .001), and >2 units of non-RBCs transfused (OR, 1.79; 95% CI, 1.60-2.00; P < .001). In the 5 hospitals using preoperative platelet function testing to guide timing of surgery, there were greater odds for DAPT within 5 days (OR, 1.33; 95% CI, 1.22-1.45; P < .001), fewer RBCs >2 units transfusions (22% vs 33%; P < .001), and non-RBCs >2 units (17% vs 28%; P < .001) transfusions within DAPT patients.

CONCLUSIONS

There is significant variability in DAPT usage within 5 days of CABG between hospital centers. Preoperative platelet function testing may allow for earlier timing of surgery for those on DAPT without increased bleeding risks.

Oral Antiplatelet Therapy Administered Upstream to Patients With NSTEMI

To describe from a noninterventional registry (Utilization of Ticagrelor in the Upstream Setting for Non-ST-Segment Elevation Acute Coronary Syndrome), the short-term ischemic and hemorrhagic outcomes in patients with non-ST elevation myocardial infarction (MI) are managed with a loading dose (LD) of a P2Y₁₂ inhibitor (P2Y₁₂i) given at least 4 hours before diagnostic angiography and delineation of coronary anatomy. Prior data on the effects of such “upstream loading” have been inconsistent.

The role of PSGL-1 in pathogenesis of systemic inflammatory response and coagulopathy in endotoxemic mice

INTRODUCTION

Endotoxemia often results in systemic inflammatory response syndrome (SIRS), coagulation disturbance and acute lung injury (ALI), and such a condition is associated with the activation of platelets, leukocytes and vascular endothelial cells (VECs). P-selectin glycoprotein ligand 1 (PSGL-1) is a key regulatory molecule in the activation of platelets, leukocytes and VECs. However, it still remains largely unexplored whether PSGL-1 plays an important role in SIRS, coagulation dysfunction and ALI of endotoxemia. In the present study, we aimed to study the role of PSGL-1 in above-mentioned situations using endotoxemic mice.

MATERIALS AND METHODS

An endotoxemia model was established in BALB/c mice via lipopolysaccharide (LPS) administration. Moreover, the mice were simultaneously injected with PSGL-1 antibody for intervention. The survival rate, morphologic changes of lung tissues, platelet-leukocyte adhesion, tissue factor expression on leukocytes, fibrinogen deposition in lung tissues, serum levels of inflammatory factors and the activation of VECs were determined.

RESULTS

The results showed that the aggregation and recruitment of platelets and leukocytes in lung tissues, the expression of tissue factor on leukocytes, the serum levels of inflammatory factors, the activation of VECs, and the fibrinogen deposition in lung tissues were increased in endotoxemic mice, which were significantly alleviated by administration of PSGL-1 antibody. Moreover, blockade of PSGL-1 markedly increased survival rate, and alleviated coagulation disturbance and lung injury in endotoxemic mice.

CONCLUSIONS

Taken together, PSGL-1 played an important role in pathogenesis of SIRS and coagulation dysfunction and ALI in endotoxemic mice.

Clopidogrel reduces lipopolysaccharide-induced inflammation and neutrophil-platelet aggregates in an experimental endotoxemic model

Platelet activation contributes to organs failure in inflammation and plays an important role in endotoxemia. Clopidogrel inhibits platelet aggregation and activation. However, the role of clopidogrel in modulating inflammatory progression of endotoxemia remains largely unexplored. Therefore, we investigated the role of clopidogrel on the activation of platelet and leukocytes in lipopolysaccharide (LPS)-induced inflammation in mice. Animals were treated with clopidogrel or vehicle before LPS induction. The expression of neutrophil-platelet aggregates and platelet activation and tissue factor was determined. Immunofluorescence was used to analyze platelet-leukocyte interactions and tissue factor (TF) expression on leukocytes. Clopidogrel pretreatment markedly decreased lung damage, inhibited platelet-neutrophil aggregates and TF expression. In addition, clopidogrel reduced thrombocytopenia and affected the number of circulating white blood cell in endotoxemia mice. Moreover, clopidogrel also reduced platelet shedding of CD40L and CD62P in endotoxemic mice. Taken together, clopidogrel played an important role through reducing platelet activation and inflammatory process in endotoxemia.