Association between perioperative management of antiplatelet agents and risk of post-endoscopic submucosal dissection bleeding in early gastric cancer: analysis of a nationwide multicenter study.

BACKGROUND AND AIMS: Data are lacking regarding post-endoscopic submucosal dissection (ESD) bleeding in patients with early gastric cancer (EGC) who take antiplatelet agents (APAs), particularly in those taking thienopyridine and cilostazol. We aimed to clarify the association between the status of APA medication and post-ESD bleeding risk. METHODS: This study is a secondary analysis using data from a recently conducted nationwide multicenter study in Japan. We retrospectively reviewed patients treated with APAs or on no antithrombotic therapy recruited from 33 institutions who underwent ESD for EGC between November 2013 and October 2016. The primary outcome of this study was the relationship between the rate of post-ESD bleeding and the status of each APA medication. RESULTS: A total of 9736 patients were included in the analysis. Among 665 aspirin users, the continuation group was significantly associated with post-ESD bleeding (odds ratio [OR], 2.79; 95% confidence interval [CI], 1.77-4.37). Among 227 thienopyridine users, the aspirin or cilostazol replacement group was not significantly associated with post-ESD bleeding (OR, 1.85; 95% CI, .72-4.78). Among 158 cilostazol users, there was no significant association with post-ESD bleeding, irrespective of medication status. The rate of post-ESD bleeding was approximately 10% to 20% irrespective of the status of APA administration among dual-antiplatelet therapy users. No patients experienced thromboembolic events in this study. CONCLUSIONS: Replacement of thienopyridine with aspirin or cilostazol may be acceptable for minimizing both the risk of post-ESD bleeding and thromboembolism in patients with EGC. In patients on cilostazol monotherapy undergoing ESD, continuation of therapy may be acceptable.

The effect of antithrombotic drug use on delayed bleeding with esophageal endoscopic resection.

BACKGROUND AND AIM: Whether antithrombotic drugs increase the risk of post-esophageal endoscopic resection bleeding is unknown. This study examined the effect of antithrombotic drugs, aspirin, thienopyridine, direct oral anticoagulants (DOAC), and warfarin, on post-esophageal endoscopic resection bleeding. METHODS: We enrolled 957 patients (1202 esophageal tumors) treated with endoscopic resection and classified them based on antithrombotic drug use as no use, aspirin, thienopyridine, DOAC, and warfarin. Patients using antiplatelet drugs (i.e. aspirin and thienopyridine) were further sub-classified based on their continued or discontinued use before endoscopic resection. The bleeding rates were compared between these groups to assess the effects of antithrombotic drug use and interruption of antiplatelet therapy on post-esophageal endoscopic resection bleeding. RESULTS: The post-endoscopic resection bleeding rate was 0.3% (95% CI, 0.1-1) in the group without antithrombotic drug use, 4.5% (95% CI, 0.1-23) in the aspirin-continued group, 2.9% (95% CI, 0.1-15) in the aspirin-discontinued group, 0% (95% CI, 0-78) in the replaced thienopyridine with aspirin group, 0% (95% CI, 0-26) in the thienopyridine-discontinued group, 13% (95% CI, 1.6-38) in the DOAC group, and 0% (95% CI, 0-45) in the warfarin group. The post-endoscopic resection bleeding rate in the DOAC group was significantly higher than that in the group without antithrombotic drugs (P = 0.003). The post-endoscopic resection bleeding rates did not differ between the other groups. CONCLUSIONS: Our results suggest that discontinuing aspirin is not necessary for esophageal endoscopic resection while we must be careful regarding DOAC.

Impact of Reticulated Platelets on the Antiplatelet Effect of the Intravenous P2Y12-Receptor Inhibitor Cangrelor.

BACKGROUND: Reticulated platelets are associated with impaired antiplatelet response to irreversibly acting P2Y12-receptor inhibitors. However, the impact of reticluated platelets (RP) on the reversibly acting injectable P2Y12-receptor inhibitor cangrelor is unknown. Thus, this study sought to investigate the influence of RP on cangrelor and transitioning strategies to oral P2Y12-receptor inhibitors. METHODS: This study randomized 110 patients undergoing elective percutaneous coronary intervention with use of cangrelor to different oral transitioning strategies loading with prasugrel 60 mg or ticagrelor 180 mg at the start of cangrelor (n = 45 each) or loading with clopidogrel 600 mg after discontinuation of cangrelor (n = 20). ADP-induced platelet reactivity was assessed by impedance aggregometry. Reticulated platelets were analysed by an automated whole blood flow cytometry and described as immature platelet count. RESULTS: There was no correlation of reticulated platelets and ADP-induced platelet reactivity in patients under treatment with cangrelor (r = 0.06, p = 0.47). This finding was consistent in all three transitioning strategies. On day 1 following treatment with cangrelor, the correlation of reticulated platelets and platelet reactivity was detectable again in patients receiving thienopyridines but not ticagrelor (all patients r = 0.37, p < 0.001; clopidogrel: r = 0.59, p = 0.01; prasugrel: r = 0.47, p < 0.001; ticagrelor r = 0.22, p = 0.13). CONCLUSION: Platelet inhibition is not influenced by levels of reticulated platelets during infusion of cangrelor independent of oral P2Y12-receptor inhibitor transitioning strategy. These findings underline the potency of cangrelor as immediate and reversibly acting P2Y12-receptor inhibitor.

Dual antiplatelet therapy is associated with prolonged survival after lower extremity revascularization.

BACKGROUND: Dual antiplatelet therapy (DAPT) after coronary stenting prolongs survival by preventing both in-stent thrombosis and other cardiovascular atherothrombotic events. Patients with peripheral artery disease (PAD) typically have a heavy burden of unrevascularized coronary artery disease and also stand to benefit from increased atherothrombotic protection with DAPT. The potential benefit of DAPT compared with aspirin alone in patients with PAD is not well described. METHODS: We identified all patients undergoing an initial elective lower extremity revascularization (bypass or endovascular) from 2003 to 2016 in the Vascular Quality Initiative registry discharged on aspirin or aspirin plus a thienopyridine antiplatelet agent (DAPT). We first estimated models predicting the likelihood of receiving DAPT and then used inverse probability weighting to account for baseline differences in the likelihood of receiving DAPT and compared late survival. For sensitivity analysis, we also performed Cox proportion hazard modeling on the unweighted cohorts and generated adjusted survival curves. RESULTS: We identified 57,041 patients undergoing lower extremity revascularization (28% bypass). Of 15,985 bypasses (69% for critical limb ischemia [CLI]), 38% were discharged on DAPT. Of 41,056 endovascular interventions (39% for CLI), 69% were discharged on DAPT. Analyses using inverse probability weighting demonstrated a small survival benefit to DAPT at 1 year for bypass (93% vs 92% [P = .001]) and endovascular interventions (93% vs 92% [P = .005]) that was sustained through 5 years of follow-up (bypass, 80% vs 78% [P = .004]; endovascular, 76% vs 73% [P = .002]). When stratified by severity of PAD, DAPT had a survival benefit for patients with CLI undergoing bypass (5 years, 70% vs 66% [P = .04]) and endovascular intervention (5 years, 71% vs 67% [P = .01]) but not for patients with claudication (bypass, 89% vs 88% [P = .36]; endovascular, 87% vs 85% [P = .46]). The protective effect of DAPT was similar when using Cox proportional hazard models after bypass (hazard ratio, 0.81 [95% confidence interval, 0.72-0.90]) and endovascular intervention (hazard ratio, 0.89 [95% confidence interval, 0.83-0.95]). CONCLUSIONS: DAPT at time of discharge was associated with prolonged survival for patients with CLI undergoing lower extremity revascularization but not for those with claudication. Further research is needed to quantify the risks associated with DAPT and to identify subgroups at increased risk of thrombotic and bleeding complications to guide medical management of patients with PAD.

Effects of P2Y12 receptor antagonists beyond platelet inhibition--comparison of ticagrelor with thienopyridines.

The effect and clinical benefit of P2Y12 receptor antagonists may not be limited to platelet inhibition and the prevention of arterial thrombus formation. Potential additional effects include reduction of the pro-inflammatory role of activated platelets and effects related to P2Y12 receptor inhibition on other cells apart from platelets. P2Y12 receptor antagonists, thienopyridines and ticagrelor, differ in their mode of action being prodrugs instead of direct acting and irreversibly instead of reversibly binding to P2Y12 . These key differences may provide different potential when it comes to additional effects. In addition to P2Y12 receptor blockade, ticagrelor is unique in having the only well-documented additional target of inhibition, the equilibrative nucleoside transporter 1. The current review will address the effects of P2Y12 receptor antagonists beyond platelets and the protection against arterial thrombosis. The discussion will include the potential for thienopyridines and ticagrelor to mediate anti-inflammatory effects, to conserve vascular function, to affect atherosclerosis, to provide cardioprotection and to induce dyspnea.

Management of acute coronary syndromes in a developing country; time for a paradigm shift? an observational study.

BACKGROUND: There are limited contemporary data on the presentation, management and outcomes of acute coronary syndromes (ACS) in Sri Lanka. We aimed to identify the critical issues that limit optimal management of ACS in Sri Lanka. METHODS: We performed a prospectively observational study of 256 consecutive patients who presented with ACS between November 2011 and May 2012 at a tertiary care general medical unit in Sri Lanka. RESULTS: We evaluated data on presentation, management, in-hospital mortality, and major adverse cardiovascular events (MACE) of participants. Smoking, alcohol abuse, and obesity were more common in patients with ST elevation myocardial infarction (STEMI) (P < 0.05). Discharge diagnoses were STEMI in 32.8 % (84/256) and unstable angina (UA)/non-ST elevation myocardial infarction [NSTEMI] in 67.1 % (172/256) of participants. The median time (IQR) from onset of pain to presentation was 60 (319) minutes for STEMI and 120 (420) for UA/NSTEMI (P = 0.058). A median delay of 240 min was noted in patients who had presented initially to smaller hospitals. Cardiac markers were assessed in only 35 % of participants. In-hospital anti-platelet use was high (>92 %). Only 70.2 % of STEMI patients received fibrinolytic therapy. Fewer than 20 % of patients were received fibrinolytic therapy within 30 min of arrival. Major adverse cardiac events (MACE) were recorded in 11.9 % of subjects with STEMI and 11.6 % of those with UA/NSTEMI (P = 0.5). According to logistic regression analysis, body mass index (P = 0.045) and duration of diabetes (P = 0.03) were significant predictors of in-hospital MACE. On discharge, aspirin, thienopyridine, and statins were prescribed to more than 90 % of patients. Only one patient underwent coronary angiography during the index admission. CONCLUSIONS: Delays in presentation and in initiation of thrombolytic therapy and coronary interventions are key hurdles that need attention to optimize ACS care in Sri Lanka.

Genetic determined low response to thienopyridines is associated with higher systemic inflammation in smokers.

AIM: To investigate whether the interactions of CYP2C19*2 and CYP2C19*17 with smoking are associated with the levels of P2Y12 receptor inhibition and CRP, in on-thienopyridine post-stenting patients. METHODS & RESULTS: At 1-month follow-up, the interactions of smoking and CYP2C19 polymorphisms on the vasodilator-stimulated phosphoprotein - platelet reactivity index (VASP PRI), and CRP were explored in three metabolizing groups (1128 patients) as follow: poor metabolizers (*2 carriers/*17 noncarriers); intermediate metabolizers (*2 carriers/*17 carriers or *2 noncarriers/*17 noncarriers); and ultrarapidmetabolizers (*2 allele noncarriers/*17 carriers). The interactions of metabolizing status and smoking was significant for CRP (p = 0.001) but not for VASP PRI (p = 0.734). CONCLUSION: Interaction between CYP2C19 polymorphisms and smoking modifies on-treatment CRP level of post-stenting, on-thienopyridine patients. This effect seems to be independent to the level of P2Y12 receptor inhibition.

Thienopyridine derivatives as risk factors for bleeding following high risk endoscopic treatments: Safe Treatment on Antiplatelets (STRAP) study.

BACKGROUND AND STUDY AIMS: The optimal method of perioperative management of antiplatelet agents during endoscopic procedures that carry a high risk of bleeding is still controversial. The aim of this study was to evaluate the safety of continuing aspirin treatment during these procedures in an Asian population. PATIENTS AND METHODS: A multicenter, prospective, observational cohort study was conducted at six high volume endoscopy centers in Japan. The study included patients at high risk of thromboembolism who were regularly taking antiplatelet agents (e. g. thienopyridine derivatives and aspirin). Enrolled patients continued their aspirin therapy, and underwent endoscopic procedures that had a high risk of bleeding for treatment of lesions in the upper and lower gastrointestinal tracts. The primary end point was the rate of major bleeding complications after endoscopic procedures. RESULTS: The study was terminated in accordance with predetermined safety criteria because 7 of 28 consecutive patients experienced major bleeding complications (25.0 %; 95 % confidence interval 10.7 % - 44.9 %). All major bleeding complications occurred following endoscopic submucosal dissection (ESD; 6 stomach, 1 colon). Univariate analysis showed that postoperative administration of thienopyridine derivatives was the only significant factor associated with postoperative bleeding (P = 0.01). Subanalysis of gastric ESD (23 lesions in 19 patients) confirmed that the administration of thienopyridine derivatives (P = 0.01) and that of multiple agents (P = 0.02) were the significant factors. All bleeding complications (postoperative day 11.2 ±â€Š3.5) occurred after resuming thienopyridine derivative therapy postoperatively (postoperative day 2.3 ±â€Š2.4). CONCLUSION: In Asian patients taking thienopyridine derivatives with aspirin, cautious postoperative care is necessary for those undergoing endoscopic procedures that are associated with a high risk of bleeding, especially gastric ESD. Continuation of aspirin alone during these endoscopic procedures may be acceptable. STUDY REGISTRATION: UMIN000009176.

Antiplatelet and anticoagulant drugs management before gastrointestinal endoscopy: do clinicians adhere to current guidelines?

BACKGROUND: Managing antiplatelet and anticoagulant drugs before endoscopy may be challenging. AIMS: To assess whether the pre-endoscopic management of antiplatelet/anticoagulant drugs is adherent to current guidelines and the influence of patients' characteristics, referring physician's specialty, type of endoscopic procedure and therapeutic regimen on adherence. METHODS: Two hundred and twenty patients taking aspirin, thienopyridines or warfarin and scheduled for upper endoscopy (± biopsies), variceal band ligation, colonoscopy (± biopsies or polypectomy), were prospectively analyzed. RESULTS: In 109 patients (49.5%) the management of antiplatelet/anticoagulant drugs was thoroughly compliant with guidelines. Neither demographic characteristics, nor in/outpatient status, nor type of endoscopic procedure, nor physician's specialty influenced the adherence but the therapeutic regimen had a significant impact (p < 0.0001) as compliance was less likely in patients on warfarin. Unwarranted drugs withholding was more frequent before colonoscopy than upper endoscopy (p = 0.0001). Warfarin was stopped longer than recommended more frequently than aspirin (p = 0.009). The International Normalized Ratio was properly checked before endoscopy in 47.7% of patients. Among the 55 patients who withheld warfarin, the decision about bridging to low molecular weight heparin was appropriate in 21 (38.2%). CONCLUSIONS: Compliance with guidelines is low especially in the management of warfarin, both among gastroenterologists and other physicians.

Aspirin, clopidogrel, and the surgeon.

The rising use of antiplatelet therapy for primary prevention and secondary prevention of cardiovascular and cerebrovascular events poses a dilemma for physicians in the perioperative period. The proven benefits of aspirin in preventing further thrombotic events in patients with prior ACS or stroke make it difficult to withdraw this therapy. The risk of hypercoagulability associated with surgery is also independent of antiplatelet withdrawal, but adds to the rebound effect of platelet responsiveness. Therefore, aspirin should be continued whenever feasible. Similarly, the use of thienopyridines such as clopidogrel, especially for the prevention of stent thrombosis, should be maintained for at least the recommended time frame, if not longer. It is recognized that maintaining antiplatelet therapy is also not without risk, as bleeding complications have been well documented. Unfortunately, current perioperative guidelines do not often provide a simple solution for management. Therefore, the risk of bleeding has to be weighed against the risk of thrombosis, and decisions should be made with all providers caring for the patient on an individual basis.

The role of P2Y12 receptor and activated platelets during inflammation.

Platelets play an important role not only during thrombosis, but also in modulating immune responses through their interaction with immune cells and by releasing inflammatory mediators upon activation. The P2Y12 receptor is a Gi-coupled receptor that not only regulates ADP-induced aggregation but can also dramatically potentiate secretion, when platelets are activated by other stimuli. Considering the importance of P2Y12 receptor in platelet function, a class of antiplatelet drugs, thienopyridines, have been designed and successfully used to prevent thrombosis. This review will focus on the role of activated platelets in inflammation and the effects that P2Y12 antagonism exerts on the inflammatory process. A change in platelet functions was noted in patients treated with thienopyridines during inflammatory conditions, suggesting that platelets may modulate the inflammatory response. Further experiments in a variety of animal models of diseases, such as sepsis, rheumatoid arthritis, myocardial infarction, pancreatitis and pulmonary inflammation have also demonstrated that activated platelets influence the inflammatory state. Platelets can secrete inflammatory modulators in a P2Y12-dependent manner, and, as a result, directly alter the inflammatory response. P2Y12 receptor may also be expressed in other cells of the immune system, indicating that thienopyridines could directly influence the immune system rather than only through platelets. Overall the results obtained to date strongly support the notion that activated platelets significantly contribute to the inflammatory process and that antagonizing P2Y12 receptor can influence the immune response.

Thienopyridines resistance and recovery of platelet function after discontinuation of thienopyridines in cardiac surgery patients.

OBJECTIVES: Patients who undergo cardiac operations under the effects of thienopyridines have a greater risk of major postoperative bleeding, transfusions and surgical revision due to bleeding. Discontinuation of thienopyridine is suggested but an adequate recovery period following discontinuation is still under debate, with opinions ranging from 3 to 7 days. The aim of this study was to assess the rate of recovery of thienopyridine-resistant patients and the time taken for resumption of platelet function after discontinuation of thienopyridine, in the setting of patients scheduled for cardiac operations. METHODS: This was a retrospective study, based on 344 patients screened for platelet aggregation before cardiac operations. All the patients received thienopyridines within 7 days prior to the test. Multiple electrode aggregometry adenosine diphosphate test was used to assess platelet aggregation before the operation. RESULTS: Thienopyridine resistance rate was 28%. Patients receiving clopidogrel had a significantly higher rate (32%) of resistance, compared with those receiving ticlopidine (14%) and thienopyridine resistance was significantly associated with platelet count (P = 0.006). The time taken to recover platelet function after thienopyridine discontinuation was variable between individuals; the only factor associated with a faster recovery time was the serum bilirubin value (P = 0.002). Platelet aggregation values high enough to avoid major bleeding were reached 3 days after discontinuation (95% confidence interval: 2-4 days); however, a complete recovery of platelet function was reached only after 8 days (95% confidence interval: 7-9 days). CONCLUSIONS: Patient-specific factors determine the effectiveness of thienopyridine treatment and platelet function recovery rate. Among these, platelet count (for thienopyridine resistance) and serum bilirubin values (for platelet function recovery rate) should be considered.

The postoperative bleeding rate and its risk factors in patients on antithrombotic therapy who undergo gastric endoscopic submucosal dissection.

BACKGROUND: There is a lack of consensus regarding the risk of postoperative hemorrhage in patients on antithrombotic therapy who undergo endoscopic submucosal dissection (ESD).We examined postoperative bleeding rates and risk factors for postoperative hemorrhage from post-ESD gastric ulcers in patients on antithrombotic therapy. METHODS: The subjects of this study were 833 patients who underwent ESD of gastric tumors. Of these, 743 were not on antithrombotic therapy and 90 were on some form of antithrombotic therapy (46 on low-dose aspirin (LDA) only, 23 on LDA + thienopyridine, and 21 on LDA + warfarin). All patients commenced proton pump inhibitor (PPI) therapy immediately postoperatively. Antiplatelet agents were discontinued for 7 days preoperatively and postoperative Day 1, and anticoagulants for 5 days preoperatively and postoperative Day 1. RESULTS: The postoperative bleeding rate in the antithrombotic group was 23.3%, significantly higher than the 2.0% observed in the non-antithrombotic group. Significant differences were seen in patients in the antithrombotic group with and without postoperative bleeding according to ESD duration (p = 0.041), PPI + mucosal protective agent combination therapy (p = 0.039), and LDA + warfarin combination therapy (p < 0.001). Multivariate analysis of these factors yielded odds ratios of 1.04 for ESD duration, 14.83 for LDA + warfarin combination therapy, and 0.27 for PPI + mucosal protective agent combination therapy. CONCLUSIONS: The risk of postoperative hemorrhage following gastric ESD was higher in patients with antithrombotic therapy than in those without that therapy. Among these patients, LDA + warfarin combination therapy and longer ESD duration were significant risk factors for postoperative bleeding. On the contrary, a mucosal protective agent to PPI therapy, lowering the odds ratio for postoperative bleeding, which suggests that the addition of a mucosal protective agent might be effective in preventing post-ESD hemorrhage in patients on antithrombotic therapy.

Impaired platelet P2Y12 inhibition by thienopyridines in chronic kidney disease: mechanisms, clinical relevance and pharmacological options.

Patients with chronic kidney disease (CKD) represent an increasing proportion of the population undergoing percutaneous coronary intervention (PCI) and up to 40% of the patients treated for acute coronary syndrome (ACS). Several studies and registries in the setting of ACS and elective PCI have reported a negative association between CKD and mortality, stent thrombosis, post-procedural ischaemic events and bleeding events. Pharmacological inhibition of the adenosine diphosphate receptor by thienopyridines or ticagrelor and disruption of the cyclooxygenase pathway by aspirin constitute the current standards of care to prevent thrombotic complications following stent-based PCI. In CKD patients, the avoidance of anti-platelet therapy may be driven by the lack of clinical trial data to support its efficacy, by errors or omissions, or by a reluctance to use this therapy in a population characterized by its enhanced bleeding risk. However, there is growing evidence to suggest that a severely decreased glomerular filtration rate per se, independent of the presence of diabetes mellitus, is an important determinant of high residual platelet reactivity under a clopidogrel maintenance dose. Recent reports have emphasized that the impact of impaired platelet inhibition by thienopyridines is of paramount importance in CKD patients, with an enhanced mortality rate in low-responder patients. Pharmacodynamic studies indicate the phosphodiesterase 3 inhibitor, cilostazol, the third generation thienopyridine prasugrel and the reversible P2Y12 antagonist ticagrelor to be potent strategies to overcome this biological resistance. In clinical practice, platelet function testing should be considered in CKD patients undergoing PCI, especially in those who experience thrombotic events despite dual therapy. Newer agents should be contemplated in patients who display higher residual platelet aggregability after standard treatment. Among these, the non-thienopyridine P2Y12 receptor antagonist ticagrelor, which does not require biotransformation, could be the drug of choice in CKD patients with ACS. In this population, ticagrelor has been found to reduce mortality and ischaemic events with an acceptable bleeding risk.

Tailored Thienopyridine therapy: no urgency for CYP2C19 genotyping.

Between 20% and 50% of cardiovascular patients treated with clopidogrel, an anti-P2Y12 drug, display high on-treatment platelet reactivity (HTPR) and are not adequately protected from major adverse cardiovascular events (MACE). Despite a minor influence of the CYP2C19*2 genetic variant on the pharmacodynamic response to clopidogrel (5% to 12%) and a limited or absent value for predicting stent thrombosis and MACE, this latter polymorphism is currently considered an important candidate to tailor anti-P2Y12 therapy during percutaneous coronary intervention. Seven studies have examined the value of CYP2C19*2 for predicting HTPR in comparison to a specific pharmacodynamic assay (VASP assay). Overall, the summarized sensitivity of the CYP2C19*2 genotype for predicting HTPR was 37.6% (95% CI: 32.2 to 43.3%), yielding a negative likelihood ratio of only 0.77 (95% CI: 0.68 to 0.86) which confirms its limited value as a routine clinical aid. A tailored anti-P2Y12 treatment strategy restricted to CYP2C19*2 carriers may be of some help, but this restrictive approach leaves out noncarriers with HTPR. As for platelet function testing, there is currently no convincing data to support that using CYP2C19*2 genotyping as a tailored anti-P2Y12 treatment would be an effective strategy and there is no urgency for CYP2C19 genotyping in clinical practice. Strategies incorporating genotyping, phenotyping, and clinical data in a stratified and sequential approach may be more promising.

Thienopyridines and other ADP-receptor antagonists.

Platelet P2Y12 receptor inhibition plays a pivotal role in preventing thrombotic vascular events in patients with ACS and in patients undergoing percutaneous coronary intervention (PCI). Among the P2Y12 receptor inhibitors, the group of thienopyridines include ticlopidine, clopidogrel and prasugrel, all of which are orally administered prodrugs leading to irreversible P2Y12 receptor inhibition. Non-thienopyridine derivatives including ticagrelor, cangrelor and elinogrel do not require metabolic activation and lead to a reversible P2Y12 receptor inhibition in contrast to thienopyridines. The extend of platelet inhibition is subject to the administered antiplatelet agent and influenced by individual genetic and clinical factors. Insufficient platelet inhibition, termed high platelet reactivity (HPR) is associated with an increased risk for ischemic events after PCI whereas exceeding platelet inhibition results in an increased bleeding risk. Pharmacologic properties and clinical outcome data differ substantially between the existing P2Y12 receptor inhibitors. Whether individualized antiplatelet treatment incorporating different P2Y12 receptor inhibitors improves patients' clinical outcomes warrants further investigation.

The management of antithrombotic medication in skin surgery.

BACKGROUND: Approximately one in four patients undergoing dermatologic surgery takes an antithrombotic medication. When approaching the management of antithrombotic agents, procedural dermatologists must balance surgical outcomes, bleeding risks, and cardiovascular protection. Continuing antithrombotics during surgery increases the risk hemorrhage, but discontinuation of these agents may increase the risk of thrombotic events. Despite increasing evidence for continuation of antithrombotics during dermatologic surgery, few official guidelines exist, and clinicians have been slow to integrate new evidence into clinical practice. A study in 2007 reported that more than 40% of dermatologic surgeons sometimes discontinue warfarin for surgery. OBJECTIVE: This article reviews antithrombotic agents in the United States and summarize perioperative management recommendations of antithrombotic agents in skin surgery. MATERIALS AND METHODS: A review of the literature was performed focused on antithrombotic medications commercially available in the United States, including the two newest agents, dabigatran and rivaroxaban. CONCLUSION: Although there are concerns regarding bleeding, there are no reports of life-threatening hemorrhage from continued antithrombotic therapy in dermatologic surgery. Furthermore, potentially fatal cardiovascular events after cessation of medically indicated antithrombotic medications are increasingly recognized, leading to the growing acceptance that the risk of stopping most antithrombotics may outweigh the risks of bleeding incurred by continuing antithrombotic therapy.

Dual antiplatelet therapy duration and clinical outcomes following treatment with zotarolimus-eluting stents.

OBJECTIVES: We sought to evaluate differences in late safety outcomes relative to dual antiplatelet therapy (DAPT) duration in patients treated with zotarolimus-eluting stents (ZES). BACKGROUND: Despite treatment recommendations for at least 12 months of DAPT following drug-eluting stent revascularization, device-specific outcomes relative to DAPT duration are absent. METHODS: Among 2,032 patients undergoing percutaneous coronary revascularization with ZES in 5 trials, late safety events were compared relative to DAPT duration for patients with ≥ 6 months DAPT adherence and survival free of major ischemic and bleeding events. RESULTS: A total of 1,414 event-free patients on DAPT at 6 months were identified. Patient group comparisons relative to DAPT included: 6 months versus ≥ 12 months, and 6 months versus ≥ 24 months. Through 3 years, risk-adjusted ischemic event rates did not significantly differ between groups: 6 versus ≥ 12 months: death (2.7% vs. 2.2%), myocardial infarction (MI, 0.3% vs. 1.1%), and definite/probable stent thrombosis (ST, 0.3% vs. 0%); 6 versus ≥ 24 months: death (1.6% vs. 1.6%), MI (0.4% vs. 1.2%), and definite/probable ST (0.1% vs. 0.2%). Composite events also did not statistically vary between DAPT durations. In multivariable analysis, 6-month versus longer DAPT duration was not associated with increased likelihood of thrombotic events at 3-year follow-up. Major bleeding was negligible across groups. CONCLUSIONS: Among patients treated with ZES, late-term events of death, MI, stroke, and ST do not significantly differ between patients taking 6 months DAPT compared with continuation beyond 1 year. These findings merit further study to identify the appropriate duration of DAPT according to specific drug-eluting stents.

Triple antiplatelet therapy in acute coronary syndromes.

Heightened platelet activity plays a critical role in thrombus formation, which is central to acute coronary syndromes (ACS), including non-ST-segment elevation (NSTE)-ACS (comprising unstable angina pectoris and non-ST-segment elevation myocardial infarction [NSTEMI]) and ST-segment elevation myocardial infarction (STEMI), and has been implicated in poor clinical outcome. Platelets not only impact coronary thrombus but are major contributors to microcirculatory dysfunction and vascular inflammation. Efforts to inhibit platelet function, including antiplatelet therapy, are paramount to the management of ACS; thus, a growing recognition of the various pathways driving platelet activity has given rise to the need for multiple agents that impart complimentary mechanisms of action. While only inhibiting platelet activation will still allow for aggregation, i.e. the binding of glycoprotein (GP) IIb/IIIa receptors to fibrinogen, solely blocking aggregation may leave platelet-activating pathways free to sustain the production and release of various pro-inflammatory and pro-thrombotic compounds. The benefit of 'triple antiplatelet therapy', referring to the combination of aspirin, a thienopyridine or non-thienopyridine adenosine diphosphate (ADP)/P2Y12 receptor blocker and a GPIIb/IIIa inhibitor (GPI), has been demonstrated in patients with NSTE-ACS who ultimately undergo percutaneous coronary intervention (PCI) and are determined to be at an elevated risk for ischaemic events, and in patients undergoing primary PCI. It is therefore recommended by the European Society of Cardiology (ESC) and American College of Cardiology/American Heart Association. Furthermore, the rationale for adding a GPI, particularly in patients with STEMI, is backed by studies that have shown negligible effects of a 600 mg clopidogrel loading dose, despite being administered 4 hours prior to PCI. Moreover, it has been observed that the physiological state of STEMI may deem dual antiplatelet therapy ineffective, because during an acute event the absorption of clopidogrel may be impaired. Nonetheless, there is still considerable variability with respect to the use of triple antiplatelet therapy such as that documented in the Euro Heart Survey. The perception that the mortality benefit afforded by adding a GPI to dual oral antiplatelet therapy does not outweigh the risk is a likely factor. This may be fuelled by results of trials such as BRAVE-3, which, inconsistent with those for On-TIME 2, failed to prove the value of adding a GPI to dual oral antiplatelet therapy in patients with STEMI. Subsequent analyses have indeed demonstrated the positive benefit-risk ratio associated with adding a GPI and determined that the timing of GPI administration could have an impact on clinical outcome related to its impact on infarct size in patients with STEMI. Additionally, it has been presumed that a synergistic effect exists between P2Y12 inhibitors and GPIs. Triple antiplatelet therapy has a significant role to play in the management of patients with ACS managed with PCI. An understanding of patient risk status and timing of symptoms and bleeding risk is crucial to patient selection and ensuring that this therapy is optimized. Though no interaction has been noted in trials of newer, more potent antiplatelet agents, future studies are key to determining the role of this strategy in the era of these more potent agents.