Antiplatelet drugs: Potential therapeutic options for the management of neurodegenerative diseases

The blood platelet plays an important role but often remains under-recognized in several vascular complications and associated diseases. Surprisingly, platelet hyperactivity and hyperaggregability have often been considered the critical risk factors for developing vascular dysfunctions in several neurodegenerative diseases (NDDs) like Alzheimer's disease, Parkinson's disease, Huntington's disease, and multiple sclerosis. In addition, platelet structural and functional impairments promote prothrombotic and proinflammatory environment that can aggravate the progression of several NDDs. These findings provide the rationale for using antiplatelet agents not only to prevent morbidity but also to reduce mortality caused by NDDs. Therefore, we thoroughly review the evidence supporting the potential pleiotropic effects of several novel classes of synthetic antiplatelet drugs, that is, cyclooxygenase inhibitors, adenosine diphosphate receptor antagonists, protease-activated receptor blockers, and glycoprotein IIb/IIIa receptor inhibitors in NDDs. Apart from this, the review also emphasizes the recent developments of selected natural antiplatelet phytochemicals belonging to key classes of plant-based bioactive compounds, including polyphenols, alkaloids, terpenoids, and flavonoids as potential therapeutic candidates in NDDs. We believe that the broad analysis of contemporary strategies and specific approaches for plausible therapeutic treatment for NDDs presented in this review could be helpful for further successful research in this area.

Risk factors, diagnosis and management of venous thromboembolic disease in pregnancy

Venous thromboembolism (VTE) in pregnancy is a leading cause of maternal morbidity and mortality. However, despite the significant associated clinical burden and potentially devastating societal impact, there is still a paucity of data surrounding its prevention and management. Consequently, international guideline recommendations vary widely. Exclusion of pregnant women from clinical trials in the past has contributed to knowledge gaps. However, recently published and ongoing studies demonstrate that excellent clinical trials in pregnancy are achievable. This review will discuss prevention, diagnosis and treatment of VTE in pregnancy, and will also explore priorities for future research.

Venous thromboembolism in pregnancy is a leading cause of maternal morbidity and mortality. However, individualised clinical risk assessment and recent advances in clinical prediction rules for pulmonary embolism have the potential to improve management.https://bit.ly/3mjtHg2

Hemostatic efficacy of two topical adjunctive hemostats in a porcine spleen biopsy punch model of moderate bleeding

Topical hemostatic agents have become essential tools to aid in preventing excessive bleeding in surgical or emergency settings and to mitigate the associated risks of serious complications. In the present study, we compared the hemostatic efficacy of SURGIFLO^® Hemostatic Matrix Kit with Thrombin (Surgiflo-flowable gelatin matrix plus human thrombin) to HEMOBLAST™ Bellows Hemostatic Agent (Hemoblast-a combination product consisting of collagen, chondroitin sulfate, and human thrombin). Surgiflo and Hemoblast were randomly tested in experimentally induced bleeding lesions on the spleens of four pigs. Primary endpoints included hemostatic efficacy measured by absolute time to hemostasis (TTH) within 5 min. Secondary endpoints included the number of product applications and the percent of product needed from each device to achieve hemostasis. Surgiflo demonstrated significantly higher hemostatic efficacy and lower TTH (p < 0.01) than Hemoblast. Surgiflo-treated lesion sites achieved hemostasis in 77.4% of cases following a single product application vs. 3.3% of Hemoblast-treated sites. On average, Surgiflo-treated sites required 63% less product applications than Hemoblast-treated sites (1.26 ± 0.0.51 vs. 3.37 ± 1.16). Surgiflo provided more effective and faster hemostasis than Hemoblast. Since both products contain thrombin to activate endogenous fibrinogen and accelerate clot formation, the superior hemostatic efficacy of Surgiflo in the porcine spleen punch biopsy model seems to be due to Surgiflo's property as a malleable barrier able to adjust to defect topography and to provide an environment for platelets to adhere and aggregate. Surgiflo combines a flowable gelatin matrix and a delivery system well-suited for precise application to bleeding sites where other methods of hemostasis may be impractical or ineffective.

Combination targeting of 'platelets + fibrin' enhances clot anchorage efficiency of nanoparticles for vascular drug delivery

Occlusive thrombosis is a central pathological event in heart attack, stroke, thromboembolism, etc. Therefore, pharmacological thrombolysis or anticoagulation is used for treating these diseases. However, systemic administration of such drugs causes hemorrhagic side-effects. Therefore, there is significant clinical interest in strategies for enhanced drug delivery to clots while minimizing systemic effects. One such strategy is by using drug-carrying nanoparticles surface-decorated with clot-binding ligands. Efforts in this area have focused on binding to singular targets in clots, e.g. platelets, fibrin, collagen, vWF or endothelium. Targeting vWF, collagen or endothelium maybe sub-optimal since in vivo these entities will be rapidly covered by platelets and leukocytes, and thus inaccessible for sufficient nanoparticle binding. In contrast, activated platelets and fibrin are majorly accessible for particle-binding, but their relative distribution in clots is highly heterogeneous. We hypothesized that combination-targeting of 'platelets + fibrin' will render higher clot-binding efficacy of nanoparticles, compared to targeting platelets or fibrin singularly. To test this, we utilized liposomes as model nanoparticles, decorated their surface with platelet-binding peptides (PBP) or fibrin-binding peptides (FBP) or combination (PBP + FBP) at controlled compositions, and evaluated their binding to human blood clots in vitro and in a mouse thrombosis model in vivo. In parallel, we developed a computational model of nanoparticle binding to single versus combination entities in clots. Our studies indicate that combination targeting of 'platelets + fibrin' enhances the clot-anchorage efficacy of nanoparticles while utilizing lower ligand densities, compared to targeting platelets or fibrin only. These findings provide important insights for vascular nanomedicine design.

Severe spontaneous epistaxis: retrospective study in a tertiary ENT centre

PURPOSE

To investigate the clinical profile and outcomes of different treatment strategies in patients hospitalized for spontaneous severe epistaxis.

METHODS

This is a retrospective descriptive study of a case series of patients hospitalized for epistaxis in the University Hospital of Ghent between 2005 and 2012.

RESULTS

124 patients with, respectively, 132 episodes were included. 64% were male. The mean age was 65 years. 73% had comorbidities of which arterial hypertension was the most common. 61% were taking one or more antithrombotics and in 25.7% a recent change in the medication schedule took place. 47% of the episodes necessitated a vascular intervention. The most performed surgery was endoscopic sphenopalatine artery ligation. The 1-year success rate of conservative treatment was 47% and of vascular intervention 81%. No significant difference between the recurrence rates and need for vascular intervention of the different comorbidities and medications was detected using Pearson chi-squared and Fisher's exact testing. The overall 5-year survival rate was 83.6%.

CONCLUSIONS

The typical pattern of a patient presenting with severe epistaxis was a patient in the sixth decade, male, suffering from comorbidities and taking one or more antithrombotic agents. Based on the above-mentioned success rates of the different treatment options, we think all centres treating epistaxis should apply a well-defined protocol to guide the decision when to proceed with surgery. Furthermore, prospective research needs to precisely investigate the role played by comorbidities and their treatment in the occurrence of epistaxis and to test the effectiveness of proposed algorithms.

Use of Antiplatelet Agents in the Neurosurgical Patient

Antiplatelet agents used to treat neurovascular disease include aspirin; P2Y12 receptor antagonists clopidogrel, prasugrel, and ticagrelor; ADP antagonist ticlopidine; phosphodiesterase inhibitor dipyridamole; and glycoprotein IIb/IIIa inhibitors abciximab, eptifibatide, and tirofiban. Numerous studies have been performed evaluating their efficacy in stroke, extracranial carotid artery disease and dissection, intracranial atherosclerotic disease, and moyamoya disease. The rapid technological advancements in endovascular neurosurgical devices have also made antiplatelet therapy a necessary part of treating intracranial aneurysms. This article presents the relevant data supporting the use of antiplatelet agents in vascular neurosurgery and recommendations based on the described studies.

Dental management of patient with dual antiplatelet therapy: a meta-analysis

BACKGROUND

It is more common to need dual antiplatelet therapy (DAPT) for patients who had recently inserted coronary artery stent. However, the postoperative bleeding risk of patients in DAPT could significantly increase. The dental management of patients with antithrombotic therapy has always been a controversial problem. Focusing on this issue, this review discussed the available evidence to provide optimal strategy for patients taking dual antiplatelet agents in the dental setting.

METHODS

We searched the PubMed, Embase, ScienceDirect, Web of Science (WOS), Cochrane Library, and China National Knowledge Infrastructure (CNKI) which was performed in May 2018. Relevant articles were included according to our inclusion and exclusion criteria. Meta-analysis was conducted with fixed effects models. Subgroup analysis was used due to different dental surgeries.

RESULTS

Our meta-analysis included ten studies (continue DAPT vs. placebo, 535 patients vs.2907 patients). The quantitative results indicated that the risk of postoperative bleeding with continuing DAPT experienced significantly increase (RR = 1.95 95% CI [1.07, 3.54]; p = 0.03). There was no statistically significant difference between the postoperative bleeding rate and different dental surgeries (p = 0.72).

CONCLUSION

On the current studies, postoperative hemorrhage is exacerbated with DAPT, but it could be controlled by enhancing hemostasis methods. We recommend continuing long-term DAPT before tooth extraction.

CLINICAL RELEVANCE

In this work, we systematically evaluated and summarized the results of small clinical trials after reviewing the present literatures on this topic, so that we could propose more objective and more accurate evidence-based recommendations on dental management for patient with dual antiplatelet therapy.

The small-molecule MERTK inhibitor UNC2025 decreases platelet activation and prevents thrombosis

Essentials Signaling by Gas6 through Tyro3/Axl/Mer receptors is essential for stable platelet aggregation. UNC2025 is a small molecule inhibitor of the Mer tyrosine kinase. UNC2025 decreases platelet activation in vitro and thrombus formation in vivo. UNC2025's anti-platelet effect is synergistic with inhibition of the ADP receptor, P2Y12 .

SUMMARY

Background Growth arrest-specific protein 6 signals through the TAM (TYRO-3-AXL-MERTK) receptor family, mediating platelet activation and thrombus formation via activation of the aggregate-stabilizing αIIb β3 integrin. Objective To describe the antithrombotic effects mediated by UNC2025, a small-molecule MERTK tyrosine kinase inhibitor. Methods MERTK phosphorylation and downstream signaling were assessed by immunoblotting. Light transmission aggregometry, flow cytometry and microfluidic analysis were used to evaluate the impact of MERTK inhibition on platelet activation and stability of aggregates in vitro. The effects of MERTK inhibition on arterial and venous thrombosis, platelet accumulation at microvascular injury sites and tail bleeding times were determined with murine models. The effects of combined treatment with ADP-P2Y1&12 pathway antagonists and UNC2025 were also evaluated. Results and Conclusions Treatment with UNC2025 inhibited MERTK phosphorylation and downstream activation of AKT and SRC, decreased platelet activation, and protected animals from pulmonary embolism and arterial thrombosis without increasing bleeding times. The antiplatelet effect of UNC2025 was enhanced in combination with ADP-P2Y1&12 pathway antagonists, and a greater than additive effect was observed when these two agents with different mechanisms of inhibition were coadministered. TAM kinase signaling represents a potential therapeutic target, as inhibition of this axis, especially in combination with ADP-P2Y pathway antagonism, mediates decreased platelet activation, aggregate stability, and thrombus formation, with less hemorrhagic potential than current treatment strategies. The data presented here also demonstrate antithrombotic activity mediated by UNC2025, a novel translational agent, and support the development of TAM kinase inhibitors for clinical applications.

Postpancreatectomy Hemorrhage After Pancreatic Surgery in Patients Receiving Anticoagulation or Antiplatelet Agents

Background Postpancreatectomy hemorrhage (PPH) is a serious complication after pancreatic surgery. In this study, we evaluated PPH and thromboembolic complications after pancreatic surgery in patients with perioperative antithrombotic treatment. Methods Medical records of patients undergoing pancreatic surgery were reviewed retrospectively. Patients receiving thromboprophylaxis were given either bridging therapy with unfractionated heparin or continued on aspirin as perioperative antithrombotic treatment according to clinical indications and published recommendations. The International Study Group of Pancreatic Surgery definition of PPH was used. Risk factors associated with PPH were assessed by multivariate analysis. Results Thirty-four of 158 patients received perioperative antithrombotic treatment; this group had a significantly higher PPH rate (29.4% vs 6.5%, P = .001) and mortality (11.8% vs 2.4%, P = .039) than patients not receiving thromboprophylaxis. Multivariate analysis revealed that perioperative antithrombotic treatment was the only independent risk factor for PPH after pancreatic surgery (odds ratio 4.77; 95% CI 1.61-14.15; P = .005). Conclusions Perioperative antithrombotic treatment is an independent risk factor for PPH in patients undergoing pancreatic surgery, although this treatment effectively prevents postoperative thromboembolic events.

Treatment and prevention of gastrointestinal bleeding in patients receiving antiplatelet therapy

Antiplatelet therapy is the standard of care for the secondary prevention of acute coronary syndrome and ischemic stroke, especially after coronary intervention. However, this therapy is associated with bleeding complications such as gastrointestinal bleeding, which is one of the most common life-threatening complications. Early endoscopy is recommended for most patients with acute upper gastrointestinal bleeding. After successful endoscopic hemostasis, immediate resumption of antiplatelet therapy with proton-pump inhibitors (PPIs) is recommended to prevent further ischemic events. PPI prophylaxis during antiplatelet therapy reduces the risk of upper gastrointestinal bleeding. The potential negative metabolic interaction between PPIs and clopidogrel is still unclear.

Dental extraction can be performed safely in patients on aspirin therapy: a timely reminder

Cardiac patients on aspirin therapy may require extractions for their diseased teeth. It is a common practice among physicians and treating surgeons to stop aspirin prior to tooth extraction because of fear of bleeding complications. This practice often predisposes the patient to adverse thromboembolic events. This practice is based on theoretical risk of bleeding and on isolated case reports of excessive bleeding with aspirin therapy. The current consensus and recommendations are in favor of continuing aspirin therapy during simple tooth extraction as the bleeding complication incidence is very less and if it occurs can be controlled efficiently with local hemostasis measures.

Postoperative bleeding complications after gastric cancer surgery in patients receiving anticoagulation and/or antiplatelet agents

BACKGROUND

Perioperative antithrombotic treatment for gastric cancer patients receiving chronic anticoagulation and/or antiplatelet agents requires an understanding of potential bleeding and thromboembolic risks. However, no study has examined the safety aspects of perioperative antithrombotic treatment during radical gastrectomy. This study sought to evaluate postoperative bleeding and thromboembolic complications after radical gastrectomy in patients undergoing perioperative antithrombotic treatment.

METHODS

The medical records of patient treated by radical gastrectomy from January 2006 to December 2010 were retrospectively reviewed. Those in the thromboprophylaxis group had received one of three regimens of perioperative antithrombotic treatment according to the clinical indications of chronic anticoagulation and/or antiplatelet agents and several published evidence-based recommendations: (1) bridging therapy with unfractionated heparin; (2) continuation of aspirin; or (3) both 1 and 2. multivariate analysis was used to identify risk factors for postoperative bleeding complications after radical gastrectomy.

RESULTS

During the study period, 340 patients underwent radical gastrectomy. Of these, 62 patients received perioperative antithrombotic treatment; this thromboprophylaxis group had a significantly higher postoperative bleeding rate (8.1 vs. 0.7 %, P = 0.003). However, other complications, including thromboembolic events, were similar in the two study groups. Multivariate analysis revealed that perioperative antithrombotic treatment was the only independent risk factor of postoperative bleeding complications after radical gastrectomy (odds ratio, 8.53; 95 % confidence interval, 1.47-49.39; P = 0.017).

CONCLUSIONS

Perioperative antithrombotic treatment is an independent risk factor of postoperative bleeding complications in patients with gastric cancer undergoing radical gastrectomy, although such treatment was effective in preventing postoperative thromboembolic events.

Antiplatelet therapy in ENT surgery: a review

INTRODUCTION

Antiplatelet agents such as aspirin and clopidogrel are increasingly encountered in clinical practice. Otorhinolaryngological surgeons are involved in the peri-operative decision of whether to continue treatment and risk haemorrhage or to discontinue treatment and risk thrombosis.

METHODS

Literature relating to the risk of spontaneous or operative haemorrhage was reviewed. The morbidity and mortality associated with cessation of agents was evaluated. Published guidelines were also evaluated. A protocol for the management of antiplatelet agents in the peri-operative period, with particular reference to ENT operations, is presented.

CONCLUSION

SIGNIFICANT morbidity and mortality is associated with the premature cessation of antiplatelet agents. Data from cardiac surgery suggest that operative blood loss only marginally increases in patients on aspirin and clopidogrel. However, the management of antiplatelet agents in the peri-operative period should be made after multidisciplinary consultation.

The Management of Antiplatelet Therapy in Patients With Coronary Stents Undergoing Noncardiac Surgery

Whereas the development of coronary stents has been a major breakthrough in the treatment of coronary artery disease, stent thrombosis, associated with myocardial infarction and death, has introduced a new challenge in the care of patients with coronary stents undergoing noncardiac surgery. This review presents the authors’ recommendations regarding the optimal management of such patients. Elective surgery should be postponed for at least 6 weeks and optimally 3 months for a bare-metal stent and at least 1 year for a drug-eluting stent. On the other hand, managing a patient undergoing non-elective surgery is more difficult and necessitates a case-by-case assessment of bleeding risk versus thrombotic risk based on patient comorbidities, type of stents present, details of the coronary intervention, and type of surgical procedure. Patients with a risk of bleeding that outweighs the risk of stent thrombosis should discontinue at least clopidogrel, whereas all other patients should continue dual antiplatelet therapy throughout the perioperative period.

Perioperative management of the patient with cardiac disease

The overall incidence of perioperative death is relatively low. However, patients with coronary artery disease are at higher than average risk of perioperative cardiac complications. Thus, preoperative testing for cardiac disease should be done in certain patients in an effort to reduce postoperative mortality and morbidity. Patients who require emergent orthopaedic surgery are at greater risk of perioperative cardiac events than are those who undergo elective procedures. Certain modalities, such as beta blockers, statins, and alpha-2 agonists, may be started or continued in the postoperative period to further enhance cardiac function. We review the current recommendations for preoperative cardiac testing in orthopaedic patients and for perioperative management of orthopaedic patients with known cardiac disease.

Upper gastrointestinal bleeding in patients receiving dual antiplatelet therapy after coronary stenting

OBJECTIVE

We investigated the risk of upper gastrointestinal (UGI) bleeding and the protective effect of concomitant anti-secretory drugs during dual antiplatelet therapy administered following implantation of drug-eluting stents (DES) for coronary heart disease. Because proton pump inhibitors (PPIs) are reported to decrease the platelet inhibitory effects of clopidogrel, we also assessed cardiovascular outcomes in patients taking thienopyridine derivatives with or without anti-secretory drug.

METHODS

We retrospectively analyzed 243 patients, who underwent DES implantation between January 2006 and December 2007 and were receiving dual anti-platelet therapy post-surgery. The main outcome measurement was the presence of UGI bleeding. Cardiovascular outcomes were assessed by follow-up coronary angiography (CAG) findings. Data were collected from medical records.

RESULTS

Eight cases of UGI bleeding were observed during the follow-up period, none of whom were taking anti-secretory drugs. Among the 243 cases, 108 cases were taking anti-secretory drugs: a PPI (67 cases), and an H2 receptor antagonist (41 cases). No UGI bleeding was observed among patients who were taking concomitant anti-secretory drugs. The 1- and 2-year cumulative incidences of UGI bleeding among patients who were not taking anti-secretory drugs were 4.5% and 9.2%, respectively. When CAG findings were compared between patients not taking any anti-secretory drug, taking PPI, or taking H2RA, significantly more stenotic lesions of the coronary artery were observed in the PPI-treatment group.

CONCLUSION

Concomitant use of an anti-secretory agent was associated with a reduced risk of UGI bleeding. Use of PPI may be associated with an attenuation of the effect of dual antiplatelet therapy.

Contribution of bleeding and thromboembolic events to in-hospital mortality among patients with thrombocytopenia treated with heparin

In a population of patients experiencing thrombocytopenia while treated with heparin, bleeding and thromboses are well-appreciated complications, but their relative contributions to mortality have been less well described. In this population, the aims of this study were (1) to identify the independent predictors of bleeding and (2) to compare the incidence and the strength of association of bleeding and of new thromboses to in-hospital mortality. The independent predictors of bleeding and in-hospital mortality were identified using multivariate logistic regression models on the 1,478 patients who developed thrombocytopenia after their enrollment in the Complications After Thrombocytopenia Caused by Heparin (CATCH) study. The independent predictors of bleeding were chronic hematologic disorders, intra-aortic balloon pump, congestive heart failure, and platelet count nadir <120 x 10(9)/L. Although bleeding (n = 141 [10%]) and thromboembolic complications (n = 135 [9%]) were equally prevalent, the former was less strongly associated than the latter with in-hospital mortality (odds ratio 1.75, 95% confidence interval 1.01 to 3.03, and odds ratio 2.77, 95% confidence interval 1.67 to 4.61, respectively). In conclusion, medical management should be directed mainly at the prevention of thromboembolic complications, while additionally considering the risk for bleeding.

Laboratory assessment and perioperative management of patients on antiplatelet therapy: from the bench to the bedside

The contribution of platelets in the pathophysiology of thromboses has established antiplatelet therapy as a cornerstone for prevention or treatment of these disorders. However, patients on antiplatelet drugs undergoing surgery face the life-threatening dilemma between the risk of perioperative thrombosis by ceasing therapy and restoring platelet function versus the risk of surgical bleeding by its continuation. According to their mechanism of action, antiplatelet drugs can be conventionally classified as agents that inhibit cyclooxygenase, block the platelet adenosine diphosphate P2Y12 receptor, inhibit phosphodiesterase, or block platelet glycoprotein IIb/IIIa. Although several tests have been developed to assess platelet inhibition by most of these compounds, studies to date have not been able to reliably evaluate the diagnostic efficiency of these tests to predict hemorrhage and/or blood loss, and accordingly perioperative assessment of drug-induced platelet inhibition cannot be recommended as yet. Although several management options are available to counteract the hemorrhagic risk of surgical patients using antiplatelet agents, perioperative discontinuation of these drugs is the preferable choice wherever possible. The use of platelet transfusions should be limited where necessary to the treatment of major, life-threatening bleeding. The contribution of newer hemostatic agents, such as desmopressin and recombinant activated factor VII, is yet to be fully determined, and there remain many challenges and unresolved issues in the clinical care of these patients.

Risk and management of upper gastrointestinal bleeding associated with prolonged dual-antiplatelet therapy after percutaneous coronary intervention

Prolonged dual-antiplatelet therapy with aspirin and clopidogrel is mandatory after drug-eluting stent implantation because of the potential increased risk of late stent thrombosis. The concern regarding prolonged antiplatelet therapy is the increased risk of bleeding. Gastrointestinal bleeding is the most common site of bleeding and presents a serious threat to patients due to the competing risks of gastrointestinal hemorrhage and stent thrombosis. Currently, there are no guidelines and little evidence on how best to manage these patients who are at high risk of morbidity and mortality from both the bleeding itself and the consequences of achieving optimum hemostasis by interruption of antiplatelet therapy. Managing gastrointestinal bleeding in a patient who has undergone recent percutaneous coronary intervention requires balancing the risk of stent thrombosis against further catastrophic bleeding. Close combined management between gastroenterologist and cardiologist is advocated to optimize patient outcomes.

Facts and controversies of aspirin and clopidogrel therapy

Because of the central role of platelets in mediating ischemic events, antiplatelet agents are critical components of atherothrombosis prevention. Given their robust safety and efficacy profiles, aspirin and clopidogrel are consistently recommended by evidence-based treatment guidelines. Despite these recommendations, controversies surrounding the appropriate application of aspirin and clopidogrel remain. Questions of appropriate dosing, length of therapy, and use of combination therapy are most pressing, and considerable debate exists regarding the variability of response to antiplatelet therapy, including the definition, measurement, and clinical relevance of responsiveness. This review discusses the facts and controversies surrounding the use of aspirin and clopidogrel. Overall, despite the existing controversies, antiplatelet therapy with aspirin and/or clopidogrel remains a proven and essential therapeutic tool for safe and effective management of atherothrombotic risk in specific clinical settings.

Management of surgical patients receiving anticoagulation and antiplatelet agents

BACKGROUND

Temporary interruption of long-term anticoagulation and antiplatelet therapy during surgical procedures exposes patients to thrombotic risk. Continuation of these agents, however, is associated with an increased risk of bleeding. Managing anticoagulation can be a particular challenge in the emergency setting.

METHODS

A literature review of published articles sourced using the keywords heparin, warfarin, perioperative, antiplatelet, aspirin and surgery was undertaken. A management plan for all likely situations was developed.

RESULTS AND CONCLUSION

Based on an individual assessment of risk factors for arterial or venous thromboembolism and the risk of perioperative bleeding, it is possible to form an anticoagulant and antiplatelet management plan likely to achieve a low incidence of bleeding and thrombosis. A multidisciplinary approach is desirable.

Incidence of bleeding and compliance on prolonged dual antiplatelet therapy (aspirin + thienopyridine) following drug-eluting stent implantation

Prolonged periods of dual antiplatelet therapy (DAT), i.e., aspirin plus a thienopyridine, are currently recommended to prevent late drug-eluting stent (DES) thrombosis. The aim of our study was to determine the risk and predictors of bleeding and compliance associated with such prolongation of DAT. In this observational study we examined 2,355 consecutive patients undergoing successful DES implantation at 4 hospitals in Italy from June 2002 to December 2004. Bleeding events occurring on DAT and warfarin or in the first 30 days after stent implantation were excluded. Median duration of DAT was 209 days (interquartile range 178 to 444) and only 158 patients (6.7%) prematurely discontinued DAT. The overall bleeding rate was 1.9% (45), with major bleeding in 19 (0.8%) and minor bleeding in 26 (1.1%). Independent predictors of bleeding were DAT (hazard ratio 19.8, 95% confidence interval [CI] 3.69 to 106.34, p <0.001) and age >65 years (hazard ratio 2.15, 95% CI 1.16 to 4.00, p = 0.02). In patients on DAT, the incidence rate (30 days to 18 months) of any bleeding event was 2.57 per 100 person-years (95% CI 1.85 to 3.48) and major bleeding was 1.10 per 100 person-years (95% CI 0.65 to 1.74). In conclusion, DAT after DES implantation is well tolerated and associated with a very low risk of major bleeding.

Platelet ADP-receptor antagonists for cardiovascular disease: past, present and future

Aspirin is the foundation antiplatelet therapy for patients at risk of cardiovascular events. The thienopyridine, clopidogrel, is modestly more effective than aspirin and in patients with stroke seems to be as effective as the combination of aspirin and dipyridamole. The addition of clopidogrel to aspirin further reduces the risk of cardiovascular events in patients with acute coronary syndromes and those who undergo percutaneous coronary intervention, but uncertainty remains about whether this combination has incremental efficacy over clopidogrel monotherapy in patients with stroke or peripheral arterial disease. Clopidogrel has pharmacological limitations that have prompted the search for more effective ADP-receptor antagonists. Promising results have been achieved with the thienopyridine, prasugrel, which has been compared with clopidogrel in patients treated with aspirin. The nonthienopyridine P2Y(12) inhibitors AZD6140 and cangrelor are presently being evaluated in phase III, randomized, controlled trials.

Combined antiplatelet and anticoagulant therapy: clinical benefits and risks

The combination of anticoagulant and antiplatelet therapy is more effective than antiplatelet therapy alone for the initial and long-term management of acute coronary syndromes but increases the risk of bleeding. Antiplatelet therapy is often combined with oral anticoagulants in patients with an indication for warfarin therapy (e.g. atrial fibrillation) who also have an indication for antiplatelet therapy (e.g. coronary artery disease) but the appropriateness of such an approach is unresolved. Anticoagulation appears to be as effective as antiplatelet therapy for long-term management of acute coronary syndrome and stroke, and possibly peripheral artery disease, but causes more bleeding. Therefore, in such patients who develop atrial fibrillation, switching from antiplatelet therapy to anticoagulants might be all that is required. The combination of anticoagulant and antiplatelet therapy has only been proven to provide additional benefit over anticoagulants alone in patients with prosthetic heart valves. The combination of aspirin and clopidogrel is not as effective as oral anticoagulants in patients with atrial fibrillation, whereas the combination of aspirin and clopidogrel is more effective than oral anticoagulants in patients with coronary stents. Whether the benefits of triple therapy outweigh the risks in patients with atrial fibrillation and coronary stents requires evaluation in randomized trials.

The impact of bleeding in patients with acute coronary syndromes: how to optimize the benefits of treatment and minimize the risk

Recurrent ischemic events after an acute coronary syndrome (ACS) remain common. Antithrombotic therapy with coronary revascularization reduces the frequency of such life-threatening events. However, with the greater use of antithrombotic medications and early revascularization, bleeding has become an increasingly important problem. Not only does bleeding result in an immediate threat, but it is also associated with increased coronary artery disease mortality and reinfarction, both in the short and long term. Older patients and women, as well as patients with anemia, renal dysfunction, high-risk ACS, diabetes, hypertension and those undergoing invasive procedures, are at especially high risk for bleeding. Major bleeding is associated with a 60% increased risk of in-hospital death, and a fivefold increase in one-year mortality and reinfarction. However, the causal link between bleeding and increased coronary artery disease events is unproven. Although there is no proof that reducing bleeding events improves outcomes, the current paradigm for the management of ACS is a strategy to minimize recurrent ischemic events but also to minimize the risk of bleeding. Such a strategy includes matching the ACS risk to the most appropriate treatment, assessing the bleeding risk, using vascular access techniques to minimize bleeding, selecting the antithrombotic agent that is best for the patient, minimizing the duration of exposure to antithrombotic agents, using the correct dose of medications, recognizing the early signs of bleeding and using gastroprotective agents to minimize upper gastrointestinal bleeding.

Prevention of premature discontinuation of dual antiplatelet therapy in patients with coronary artery stents

BACKGROUND

and Overview. Dual antiplatelet therapy with aspirin and a thienopyridine has been shown to reduce cardiac events after coronary stenting. However, many patients and health care providers prematurely discontinue dual antiplatelet therapy, which greatly increases the risk of stent thrombosis, myocardial infarction and death.

CONCLUSIONS AND CLINICAL IMPLICATIONS

This advisory stresses the importance of 12 months of dual antiplatelet therapy after placement of a drug-eluting stent and educating patients and health care providers about hazards of premature discontinuation. It also recommends postponing elective surgery for one year, and if surgery cannot be deferred, considering the continuation of aspirin during the perioperative period in high-risk patients with drug-eluting stents.

Prevention of premature discontinuation of dual antiplatelet therapy in patients with coronary artery stents: a science advisory from the American Heart Association, American College of Cardiology, Society for Cardiovascular Angiography and Interventions, American College of Surgeons, and American Dental Association, with representation from the American College of Physicians

Dual antiplatelet therapy with aspirin and a thienopyridine has been shown to reduce cardiac events after coronary stenting. However, many patients and healthcare providers prematurely discontinue dual antiplatelet therapy, which greatly increases the risk of stent thrombosis, myocardial infarction, and death. This advisory stresses the importance of 12 months of dual antiplatelet therapy after placement of a drug-eluting stent and educating the patient and healthcare providers about hazards of premature discontinuation. It also recommends postponing elective surgery for 1 year, and if surgery cannot be deferred, considering the continuation of aspirin during the perioperative period in high-risk patients with drug-eluting stents.

Prevention of premature discontinuation of dual antiplatelet therapy in patients with coronary artery stents: A science advisory from the American Heart Association, American College of Cardiology, Society for Cardiovascular Angiography and Interventions, American College of Surgeons, and American Dental Association, with representation from the American College of Physicians

Dual antiplatelet therapy with aspirin and a thienopyridine has been shown to reduce cardiac events after coronary stenting. However, many patients and healthcare providers prematurely discontinue dual antiplatelet therapy, which greatly increases the risk of stent thrombosis, myocardial infarction, and death. This advisory stresses the importance of 12 months of dual antiplatelet therapy after placement of a drug-eluting stent and educating the patient and healthcare providers about hazards of premature discontinuation. It also recommends postponing elective surgery for 1 year, and if surgery cannot be deferred, considering the continuation of aspirin during the perioperative period in high-risk patients with drug-eluting stents.