Platelet Reactivity in Patients With Acute Coronary Syndromes Awaiting Surgical Revascularization

Impact of Ticagrelor Versus Clopidogrel on Bleeding Outcomes of Isolated Coronary Artery Bypass Grafting

BACKGROUND

Increased bleeding risks have been documented in patients exposed to P2Y₁₂ inhibitors within 5 days of coronary artery bypass surgery (CABG). This study aimed to determine the relative CABG bleeding risks of clopidogrel versus ticagrelor exposure and the proper time course of ticagrelor discontinuation prior to surgery.

METHODS

Clinical outcomes were assessed in 2075 isolated CABG patients, including 375 who had received P2Y₁₂ inhibitors within 5 days of surgery (155 clopidogrel, 213 ticagrelor, 7 prasugrel). BARC-4 CABG bleeding complications and perioperative blood product usage were assessed in propensity-matched P2Y₁₂-inhibited and non-P2Y₁₂-inhibited cohorts.

RESULTS

P2Y₁₂-inhibited patients (n = 375) in comparison to matched non-P2Y₁₂-inhibited patients (n = 1138) had higher rates of re-operation for bleeding (3.8 % vs 1.3 %, p = 0.003), postoperative red blood cell transfusion ≥5 units (5.7 % vs 2.7 %, p = 0.007), and intraoperative and postoperative blood product utilization (42.3 % vs 27.1 %, p < 0.001; 41.8 % vs 32.2 %, p < 0.001, respectively). Univariate predictors of BARC-4 bleeding included clopidogrel (OR: 2.145, 95 % CI: 1.131-4.067, p = 0.019) and ticagrelor discontinued within 3 days of surgery (OR: 2.153, 95 % CI: 1.003-4.169, p = 0.049). Multivariate logistic regression demonstrated that only clopidogrel exposure was an independent BARC-4 bleeding predictor (OR: 1.850, 95 % CI: 1.007-3.398, p = 0.048). Unadjusted ticagrelor patients with drug discontinuation 4-5 days prior to CABG only demonstrated higher rates of perioperative platelet transfusion, without additional signs of excessive bleeding.

CONCLUSIONS

Clopidogrel exposure within 5 days of CABG is an independent predictor of BARC-4 bleeding, whereas major ticagrelor bleeding effects are confined to drug exposure within 3 days of surgery.

Novel Platelet Function Analyzer 200 Predicts Blood Transfusion After Elective Cardiac Surgery in Patients Suspended on Dual Antiplatelet Therapy

The value of platelet function test in timing of cardiac surgery remains uncertain. Researches on correlation between Platelet Function Analyzer 200 (PFA-200) and bleeding after elective cardiac surgery are still inadequate. The objective of this study was to investigate the predictive value of PFA-200 in blood transfusion after cardiac surgery. A total of 71 patients on aspirin and P2Y12 receptor inhibitors undergoing cardiac surgery in Fuwai Hospital were enrolled. Platelet function after discontinuing of antiplatelet drugs was assessed by PFA-200 using closure time (CT). PFA-200 results before surgery were included in the statistics. The primary endpoint was postoperative blood transfusion. Seventeen patients (21.9%) received blood transfusion after cardiac surgery. The preoperative PFA-200 CT value in the transfused group was significantly higher than that in the non-transfused group (147.24 ± 85.54 s vs 98.06 ± 61.59 s, P = .011). Using 106 seconds as the dividing point, the incidence of blood transfusion in the elevated PFA-200 (CT > 106 s) group was significantly higher than those in normal PFA-200 (CT ≤ 106 s) group (10/24 patients, 41.9% vs 7/47 patients, 14.7%, P = .012). Multivariate logistic regression analysis showed that PFA-200 CT value > 106 s was an independent predictor of postoperative blood transfusion (OR: 4.05, 95%CI: 1.19-13.86, P = .026). The platelet function test PFA-200 had a predictive value for postoperative blood transfusion in elective cardiac surgery and had a promising prospect in the timing of cardiac surgery.

Coagulation and Transfusion Updates From 2021

2021 and the COVID 19 pandemic have brought unprecedented blood shortages worldwide. These deficits have propelled national efforts to reduce blood usage, including limiting elective services and accelerating Patient Blood Management (PBM) initiatives. A host of research dedicated to blood usage and management within cardiac surgery has continued to emerge. The intent of this review is to highlight this past year's research pertaining to PBM and COVID-19-related coagulation changes.

The Diagnostic Value of Combined Detection of Serum Lp-PLA2 and Hcy and Color Doppler in Elderly Patients with Acute Coronary Syndrome and Effect on Endothelial Function

Objective

To evaluate the application value of serum lipoprotein-associated phospholipase A2 (Lp-PLA2) and homocysteine (Hcy) combined with color Doppler detection in elderly patients with acute coronary syndrome (ACS) and the influence on their endothelial function.

Methods

From February 2019 to October 2020, 100 elderly patients with suspected ACS treated in our hospital were recruited and assigned (1 : 1) to a control group or an experimental group. The control group received color Doppler detection, and the experimental group received the combined detection of serum Lp-PLA2 and Hcy and color Doppler. Positive results were determined by the combined detection of the levels of LP-PLA2 and Hcy and color Doppler. The two groups were compared in terms of specificity, susceptibility, positive detection rate, negative detection rate, test accuracy, the area under the receiver operating characteristic (ROC) curve (AUC), the expression levels of interleukin-2 (IL-2), interleukin-12 (IL-12), interleukin-13 (IL-13), and the vascular endothelial function. The patients with ACS were divided into three subgroups according to the Gensini score three-quartile interval, and their Lp-PLA2 levels were calculated for analysis.

Results

The test specificity, susceptibility, positive detection rate, negative detection rate, test accuracy, and AUC in the experimental group were much better than the those in the control group (all P < 0.05), and there were no significant differences in the expression levels of IL-2, IL-12, IL-13, and vascular endothelial function between the two groups (P > 0.05). The three subgroups showed similar levels of fasting blood glucose, total cholesterol, triglyceride, high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol, apolipoprotein A-I, glutamic-pyruvic transaminase, lutamic-oxaloacetic transaminase, homocysteine, and amino-terminal pro-brain natriuretic peptide (all P > 0.05). The severe condition group had the highest Lp-PLA2 level, followed by the moderate group, and then the mild group (P < 0.05). Moreover, the levels of LP-PLA2, aspartate transaminase (AST), and N-terminal pro hormone B-type natriuretic peptide (NT-proBNP) were all influencing factors for the coronary Gensini score (all P < 0.05).

Conclusion

The combined detection of serum Lp-PLA2, Hcy, and color Doppler significantly improves the diagnostic accuracy, specificity, and susceptibility in the elderly with ACS, with little impact on their vascular endothelial function.

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.

"Tailored" antiplatelet bridging therapy with cangrelor: moving toward personalized medicine

In the setting of patients with indication to receive dual antiplatelet therapy undergoing surgery or invasive procedures, the risk of perioperative cardiac ischemic events, particularly stent thrombosis, is high, because surgery has a prothrombotic effect and antiplatelet therapy is withdrawn in order to avoid bleeding complications. Cangrelor, an intravenous P2Y₁₂ receptor antagonist, has been tested in a randomized trial as a "bridge" to cardiac surgery from discontinuation of oral P2Y₁₂ receptor antagonists. Thus, a consensus document extended its off-label use in this setting and before non-cardiac surgery. Currently, despite the implementation of a standardized bridging protocol with cangrelor, a residual risk of adverse outcome mainly due to bleeding events, still persist during the perioperative phase.Accordingly, a personalized management driven by platelet reactivity serial measurements and careful assessment of ischemic and bleeding risks has potential to optimize outcomes and costs as compared to a standardized bridging protocol, based on average pharmacodynamic data of oral P2Y₁₂ inhibitors.While specific indications for bridging have been extensively addressed in the aforementioned consensus statement, the aim of the present document is the proposal of a "tailored" clinical decision-making algorithm inspired to the principle of personalized medicine dealing with complex clinical scenarios.