Platelet function recovery after ticagrelor withdrawal in patients awaiting urgent coronary surgery

Testing P2Y12 platelet inhibitors generics beyond bioequivalence: a parallel single-blinded randomized trial

Cardiovascular diseases are the leading cause of death worldwide. Ticagrelor is an oral antiplatelet drug used in acute coronary syndrome. Although generic drugs are approved for their bioequivalence to the original product, they are not necessarily to be therapeutically equivalent. This study was conducted to prove the efficacy and safety of ticagrelor generically named Ticaloguard® compared to its brand Brilique® in healthy volunteers. A loading dose of 180 mg ticagrelor named Brilique® or Ticaloguard® followed by a 90 mg twice daily regimen as maintenance dose was given to 14 and 15 volunteers in Tica and Brili groups, respectively. The platelet aggregation on the ADP agonist was assessed at baseline and repeated 1 h and 3 h after the loading dose, on day 4 (after reaching steady-state), 12 and 24 h after discontinuation of the antiplatelet drug. Adverse effects from trial medications were noted by direct questions. It was shown that generic Ticaloguard® provides a similar therapeutic effect and safety as its branded Brilique® (p > 0.05). This will permit safe and trusted use of the generic Ticaloguard® when treating it in the same manner as Brilique®. Testing generic drug effects rather than simple bioequivalency, especially for drugs that are used in critical life-threatening situations, is crucial. We advocate applying this form of a clinical trial to test surrogate clinical efficacy for generics used in critical indications before having real-world data whenever possible.

A case report of atraumatic splenic rupture after coronary stenting and dual antiplatelet therapy: Causality or relationship?

INTRODUCTION AND IMPORTANCE

Atraumatic splenic rupture(ASR) is a rare event with challenging management, due to absence of clinical history of trauma and delayed diagnosis. Current clinical report could provide detailed information regarding clinical presentation and management to physicians.

CASE PRESENTATION

A 61 years-old woman underwent percutaneous coronary intervention(PTCA) after ST elevation myocardial infarction(STEMI). In the first day after PTCA epigastric abdominal disconfort was reported, and new PTCA excluded early complication. During hospitalization, due to anemization and hypotension CT scan was performed which revealed ASR with large hemoperitoneum. Emergency surgical splenectomy was performed. Postoperative course was uneventful and patient started 90 mg Ticageclor twice daily in the first post-operative day(POD) plus low molecular weight Heparin and restarted dual antiplatelet therapy(DAPT) the seventh POD. During follow up, patient underwent to assessment of platelet function showing normal level of DAPT inhibition. Due to the lack of pathological aggregation activity, DAPT was maintained.

CLINICAL DISCUSSION

ASR is mainly linked to oncological, malformative, inflammatory and thromboembolic conditions. Despite anticoagulant and anti-aggregating drug-related ASR has been already described, we report the first case of drug-related ASR as immediate complication of PTCA due to DAPT. After surgery, careful anti-aggregating management was required to balance in stent restenosis and hemorragic risk. Assessment of platelet activity was performed to design a tailored anti-aggregating therapy.

CONCLUSION

Drug-related ASR is dangerous complication due to the high mortality rate and misleading symptoms. After major bleeding events, such as drug-related ASR, evaluation of platelet function could provide a tailored DAPT.

The impact of dual antiplatelet therapy administration on the risk of bleeding complications during coronary artery bypass surgery

Introduction

Dual antiplatelet therapy reduces the risk of cardiovascular death, myocardial infarction and recurrence of adverse ischemic events in patients affected by acute coronary syndromes, but in patients urgently needing coronary artery surgery it can increase the risk of severe perioperative bleeding complications.

Aim

We evaluated the impact of dual antiplatelet therapy (DAPT) based on acetylsalicylic acid plus clopidogrel or ticagrelor in patients undergoing coronary artery bypass grafting (CABG).

Material and methods

Three hundred and thirty-three patients underwent coronary artery bypass grafting with DAPT discontinuation > 72 hours or 3–4 days (group A, n = 159), 48–72 hours or 2–3 days (group B, n = 126), < 24 hours or 0–1 day (group C, n = 24) prior to CABG.

Results

Operative mortality was 1.87% (group A), 0.79% (group B), absent (group C). The incidence of mediastinal re-exploration was 1.25% or 2 patients (group A), 1.59% or 2 patients (group B), 8.33% or 4 patients (group C) (p = 0.01). Group C showed postoperatively a greater incidence of a blood loss greater than 500 ml at 6 hours and a blood loss from chest tube drainages significantly higher at 6 and 24 hours (p < 0.01). Multivariate analysis showed that ongoing ticagrelor intake in group C (HR = 42.4; p = 0.02) and group C (HR = 6.9; p = 0.04) were the only independent predictors of surgical re-exploration. In group C, surgical re-exploration was 2.56% or 1/39 patients taking clopidogrel, 33.3% or 3/9 patients taking ticagrelor (p = 0.002).

Conclusions

Dual antiplatelet therapy ongoing until 1 day or 24 hours before CABG showed a significantly increased risk of bleeding complications in comparison with its discontinuation at 2–3 and > 3–4 days before, respectively. Major blood loss and surgical re-exploration were not associated with increased risk of operative all-cause or bleeding-related mortality. As expected, taking ticagrelor compared with clopidogrel in the short interval confers a higher risk of bleeding complications.

Management of Bleeding Events Associated with Antiplatelet Therapy: Evidence, Uncertainties and Pitfalls

Bleeding complications are common in patients treated with antiplatelet agents (APA), but their management relies on poor evidence. Therefore, practical guidelines and guidance documents are mainly based on expert opinion. The French Working Group on Perioperative Haemostasis provided proposals in 2018 to enhance clinical decisions regarding the management of APA-treated patients with a bleeding event. In light of these proposals, this review discusses the evidence and uncertainties of the management of patients with a bleeding event while on antiplatelet therapy. Platelet transfusion is the main option as an attempt to neutralise the effect of APA on primary haemostasis. Nevertheless, efficacy of platelet transfusion to mitigate clinical consequences of bleeding in patients treated with APA depends on the type of antiplatelet therapy, the time from the last intake, the mechanism (spontaneous versus traumatic) and site of bleeding and the criteria of efficacy (in vitro, in vivo). Specific antidotes for APA neutralisation are needed, especially for ticagrelor, but are not available yet. Despite the amount of information that platelet function tests are expected to give, little data support the clinical benefit of using such tests for the management of bleeding events in patients treated or potentially treated with APA.

Reduction of Preoperative Waiting Time before Urgent Surgery for Patients on P2Y12 Inhibitors Using Multiple Electrode Aggregometry: A Retrospective Study

P2Y₁₂ inhibitor discontinuation is essential before most surgical interventions to limit bleeding complications. Based on pharmacodynamic data, fixed discontinuation durations have been recommended. However, as platelet function recovery is highly variable among patients, a more individualized approach based on platelet function testing (PFT) has been proposed. The aim of this retrospective single-centre study was to determine whether PFT using whole blood adenosine diphosphate–multiple electrode aggregometry (ADP–MEA) was associated with a safe reduction of preoperative waiting time. Preoperative ADP–MEA was performed for 29 patients on P2Y₁₂ inhibitors. Among those, 17 patients underwent a coronary artery bypass graft. Twenty one were operated with an ADP–MEA ≥ 19 U (quantification of the area under the aggregation curve), and the waiting time was shorter by 1.6 days (median 1.8 days, IQR 0.5–2.9), by comparison with the current recommendations (five days for clopidogrel and ticagrelor, seven days for prasugrel). Platelet function recovery was indeed highly variable among individuals. With the 19 U threshold, high residual platelet inhibition was associated with perioperative platelet transfusion. These results suggest that preoperative PFT with ADP–MEA could help reduce waiting time before urgent surgery for patients on P2Y₁₂ inhibitors.

Offset of ticagrelor prior to coronary artery bypass graft surgery for acute coronary syndromes: effects on platelet function and cellular adenosine uptake

Ticagrelor is an antagonist of both platelet adenosine diphosphate (ADP) receptor P2Y₁₂ and equilibrative nucleoside transporter-1. Optimal timing of ticagrelor cessation prior to coronary artery bypass grafting (CABG) remains unclear. We characterized the offset of ticagrelor's effects on platelets and cellular adenosine uptake in ticagrelor-treated patients (n = 13) awaiting CABG. Blood was drawn prior to CABG at multiple timepoints 2 to 120 (h) after the last dose of ticagrelor. Platelet function (n = 13) was assessed with multiple electrode aggregometry (MEA), expressed as arbitrary units (U) derived from area-under-the-curve (AUC) in response to ADP, and inhibition of adenosine uptake by high-performance liquid chromatography (n = 7). Mean±SD AUC was 20.3 ± 8.2 U (2 h post-ticagrelor), 33.0 ± 18.3U (24 h), 56.6 ± 30.6U (48 h), 61.4 ± 20.2U (72 h), 82.8 ± 24.2U (96 h) and 96.0 ± 15.3U (120 h). There was a significant difference between 72 h and 120 h (p = .007), but not between 96 h and 120 h (p > .99). By 96 h, all patients had AUC >31U, an accepted cutoff below which surgical bleeding risk is increased. Adenosine uptake showed no significant differences between the timepoints. These data suggest it takes 4 days for platelet reactivity to recover sufficiently after cessation of ticagrelor to avoid the excess risk of CABG-related bleeding. Discontinuing ticagrelor had no measurable effect on cellular adenosine uptake.

Pharmacokinetic and Pharmacogenetic Factors Contributing to Platelet Function Recovery After Single Dose of Ticagrelor in Healthy Subjects

Objectives: This study aimed to elucidate the contribution of candidate single nucleotide polymorphisms (SNPs) related to pharmacokinetics on the recovery of platelet function after single dose of ticagrelor was orally administered to healthy Chinese subjects.

Methods: The pharmacokinetic profiles of ticagrelor and its metabolite AR-C124910XX (M8), and the platelet aggregation (PA), were assessed after 180 mg of single-dose ticagrelor was orally administered to 51 healthy Chinese subjects. Effects of CYP2C19^*2, CYP2C19^*3, CYP3A5^*3, UGT1A1^*6, UGT1A1^*28, UGT2B7^*2, UGT2B7^*3, SLCO1B1 388A>G, and SLCO1B1 521T>C, on the pharmacokinetics of ticagrelor and M8, and platelet function recovery were investigated.

Results: The time to recover 50% of the maximum drug effect (RT₅₀) ranging from 36 to 126 h with 46.9% CV had a remarkable individual difference and was positively associated with the half-life (t_1/2) of M8 (r = 0.3901, P = 0.0067). The time of peak concentration (T_max) of ticagrelor for CYP2C19^*3 GG homozygotes was significantly higher than that of GA heterozygotes (P = 0.0027, FDR = 0.0243). Decreased peak concentration (C_max) of M8 was significantly associated with SLCO1B1 388A>G A allele (P = 0.0152, FDR = 0.1368). CYP2C19^*2 A was significantly related to decreased C_max of M8 (P = 0.0455, FDR = 0.2048). While, the influence of these nine SNPs on the recovery of platelet function was not significant.

Conclusion: Our study suggests that the elimination of M8 is an important factor in determining the recovery of platelet function. Although CYP2C19 and SLCO1B1 genetic variants were related to the pharmacokinetics of ticagrelor or M8, they did not show a significant effect on the platelet function recovery in this study.

Clinical Trial Registration:https://clinicaltrials.gov/ct2/show/NCT03092076, identifier: NCT03092076

Effect of thrombelastography on timing of coronary artery bypass grafting

The guiding value of thrombelastography (TEG) on the selection of surgical timing for patients scheduled for coronary artery bypass grafting (CABG) was investigated. A total of 90 subjects with acute coronary syndrome (ACS) treated between February 2014 and December 2016 in Henan Provincial People's Hospital were recruited. The patients received dual antiplatelet therapy (DAPT) and were scheduled for CABG. Subjects were randomly allocated into two groups, TEG group (n=45) and non-TEG group (n=45). Patients in the TEG group withheld medications at 24 h prior to surgery and received TEG examination. Based on maximum amplitude of adenosine diphosphate (MA_ADP), subjects were further grouped into three sub-groups with MA_ADP <35 mm, 35–50 mm, and >50 mm, and accordingly received CABG within 1 day, 3–5 days and 5 days later, respectively. Subjects in the control group (non-TEG group) received CABG 5–7 days after medication withdrawal. Chest drainage volume within 24 h after surgery and red blood cell transfusion during perioperative period were compared. Other recorded parameters were incubation period, intensive care unit length of stay, hospital stay, incidence of 30-day adverse events and readmission rate. The average waiting time before CABG for patients of TEG group was shorter compared with the commonly recommended time. The red blood cell transfusions during perioperative period of subjects in TEG group and non-TEG group were significantly different (P=0.23). The median hospital stay of subjects in TEG group was shorter than that of non-TEG group (P=0.037). The bleeding amount of patients in TEG group was 220.16±80.56 ml, which was significantly lower than that of non-TEG group (435.29±90.16). The difference was statistically significant (P=0.032). The results suggested that TEG assay-based evaluation of platelet function for patients scheduled for CABG reasonably guides surgeons with appropriate surgical timing and reduces the amount of time patients wait to be treated.