Indications for Dual Antiplatelet Therapy with Aspirin and Clopidogrel: Evidence-Based Recommendations for Use

Antithrombotics and Gastrointestinal Prophylaxis: A Systematic Review

Antithrombotic medications include both antiplatelet and anticoagulants and are used for a wide variety of cardiovascular conditions. A common complication of antithrombotic use is gastrointestinal bleeding. As a result, gastrointestinal prophylaxis is a common consideration for patients on a single or combination antithrombotic regimen. Prophylaxis is typically achieved through use of either proton pump inhibitors or histamine 2 receptor antagonists. Current recommendations for use of gastrointestinal prophylaxis with concomitant use of antithrombotic medications are scarce. In this systematic review, we explore the current evidence and recommendations regarding gastrointestinal prophylaxis for patients on antiplatelet or anticoagulant therapy as well as combination regimens.

Should we stop dual anti-platelet therapy for dental extractions? An umbrella review for this dental dilemma

OBJECTIVES

Dual Anti-platelet Therapy (DAPT) are prescribed to patients who had or are at risk of cerebrovascular or cardiovascular ischemic events. This umbrella review appraises existing systematic reviews on the risk of bleeding related complications during and after dental extractions for patients on DAPT.

STUDY DATA AND SOURCES

This review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and registered to the PROSPERO (International prospective register of systematic reviews) database. A systematic electronic literature search was conducted according to the PRISMA guidelines, via PubMed, Ovid, Cochrane and Embase.

STUDY SELECTION

Four systematic reviews met the inclusion criteria and were included the analysis. They show DAPT increases the risk of bleeding related complications after dental extractions, but the differences may not be clinically significant as local haemostatic measures were adequate in controlling bleeding.

CONCLUSION

Despite the increased risk of bleeding after dental extractions in patients on DAPT, it may not be necessary to interrupt the anti-platelet therapy. Local haemostatic agents may be sufficient in controlling both the primary or secondary bleeding. On the other hand, the complications of discontinuing DAPT may be more severe and fatal.

Formation of a Rectus Sheath Hematoma Secondary to COPD Exacerbation While Taking Dual Antiplatelet Therapy

Rectus sheath hematomas can occur due to nontraumatic increases in abdominal pressure from respiratory disease such as chronic obstructive pulmonary disease (COPD). This case study describes a 59-year-old male who was on dual antiplatelet therapy after a right coronary percutaneous intervention for acute coronary syndrome. He developed abdominal pain and ecchymosis on dual antiplatelets and was found to have a rectus sheath hematoma. The hematoma resolved with conservative care and did not require surgical intervention. The etiology of rectus sheath hematoma is thought to be due to coughing spells from chronic obstructive pulmonary disease exacerbation while taking dual antiplatelet therapy. Cases of rectus sheath hematomas continue to emerge in the literature with similar patient histories, and we should be cognizant of this possible complication in patients with chronic coughing.

Colonoscopic post-polypectomy bleeding in patients on uninterruptedclopidogrel therapy: A systematic review and meta-analysis

Current guidelines recommend temporary cessation of clopidogrel for 7-10 days for patients on clopidogrel undergoing colonoscopy with polypectomy. However, recent prospective randomized controlled trials have advocated for uninterrupted clopidogrel, due to similar post-polypectomy bleeding (PPB) rates with and without continued clopidogrel therapy. Thus, a meta-analysis was conducted to assess the risk of PPB rate in patients on continued clopidogrel therapy. Systemically identified publications were used to compare the rate of PPB in patients on continued clopidogrel therapy with those who had interrupted clopidogrel therapy. The primary outcome was the incidence of PPB. The secondary outcomes were immediate PPB, delayed PPB and serious cardio-thrombotic events. This study has been registered in PROSPERO (no. CRD42018118325). A total of five studies were identified, which included 655 patients in the continued clopidogrel group and 6620 patients in the control group. There was an increased risk of PPB with continued clopidogrel [P=0.0003; risk ratio (RR), 1.96; 95% confidence interval (CI), 1.36-2.83). The rate of immediate PPB was slightly higher in the continued clopidogrel group (5.77% vs. 1.77%, respectively), but was not statistically significant (P=0.06; RR, 1.57; 95%CI, 0.98-2.51). The rate of delayed PPB was increased in the continued clopidogrel group (P=0.0008; RR, 3.10; 95%CI, 1.60-5.98). However, no significant difference in serious cardio-thrombotic events was observed within 30 days (P=0.74; RR, 0.78; 95%CI, 0.18-3.40). Although continued clopidogrel therapy decreased the incidence of serious cardio-thrombotic events, the risk of delayed PPB was increased. Therefore, endoscopists should make all preparations to prevent bleeding in the perioperative period for patients at high thrombotic risk and on continued clopidogrel therapy, if polypectomy cannot be reasonably postponed.

Effects of Cilostazol-Based Triple Antiplatelet Therapy Versus Dual Antiplatelet Therapy After Coronary Drug-Eluting Stent Implantation: An Updated Meta-Analysis of the Randomized Controlled Trials

BACKGROUND AND OBJECTIVE

The results of studies on cilostazol-based triple antiplatelet therapy (TAT) after drug-eluting stent (DES) implantation were inconsistent. To assess the effects of TAT compared with dual antiplatelet therapy (DAT) after DES/second-generation DES implantation, we performed a meta-analysis of randomized controlled trials (RCTs).

METHODS

All relevant studies evaluated were identified by searching the PubMed, EMBASE, Cochrane Library, and ISI Web of Science databases without time and language limitation. Subgroup analyses were performed to evaluate the efficacy and safety of TAT after second-generation DES implantation.

RESULTS

Eleven RCTs involving a total of 4684 patients were included. The meta-analysis showed TAT was associated with significant beneficial effects on angiographic findings of in-stent restenosis [risk ratio (RR) 0.645, 95% confidence interval (CI) 0.470-0.885; P = 0.007], in-segment restenosis (RR 0.606, 95% CI 0.450-0.817; P = 0.001), in-stent late loss (RR - 0.095, 95% CI - 0.136 to - 0.054; P < 0.0001), in-segment late loss (RR - 0.100, 95% CI - 0.139 to - 0.061; P < 0.0001), target lesion revascularization (TLR) (RR 0.570, 95% CI 0.430-0.755; P < 0.0001), and target vessel revascularization (TVR) (RR 0.523, 95% CI 0.380-0.719; P < 0.0001). No significant difference was found in outcomes of all-cause death, cardiac death, definite/probable stent thrombosis (ST), non-fatal myocardial infarction (MI), overall bleeding, and major bleeding between the two groups, as well as some minor adverse effects including palpitations, thrombocytopenia, neutropenia, and hepatic dysfunction. However, the incidence rate of rash, gastrointestinal disorders, and headache was significantly higher in TAT. The second-generation DES subgroup showed similar results, except for the indicators of all-cause death (RR 2.161, 95% CI 1.007-4.635; P = 0.048) and hepatic dysfunction (RR 0.176, 95% CI 0.031-0.995; P = 0.049).

CONCLUSIONS

Compared with DAT, cilostazol-based TAT can significantly improve the angiographic findings of in-stent and in-segment late loss, in-stent and in-segment restenosis, TLR, and TVR after DES/second-generation DES implantation. However, no benefits were observed in outcomes of all-cause death, cardiac death, ST, and MI.

Dual or Mono Antiplatelet Therapy for the Prevention of Ischemic Stroke: A Literature Review

Ischemic stroke is defined as a sudden loss of blood to the brain which results in deprivation of oxygen and other nutrients. It can be either a transient episode called as “transient ischemic attack” (TIA), or it could last longer than 24 hours giving rise to “infarction of tissues” in the central nervous system. Anti-platelet agents are widely used for the secondary prophylaxis of ischemic stroke, and amongst them, aspirin remains the drug of choice. In this literature review, we summarized the existing data regarding the ischemic type of strokes with particular attention to the use of antiplatelet agents for this purpose. The following review highlights the significance of the use of dual antiplatelet (aspirin and clopidogrel) regimen for the stroke prevention. The role of dual antiplatelet (aspirin and clopidogrel) in patients with a recent TIA (within 30 days) or severe stenosis (70%–99%) of a major intracranial artery, for 90 days, might be a beneficial approach.

Management of Anticoagulants and Antiplatelet Agents During Colonoscopy

Colonoscopy frequently is performed for patients who are taking aspirin, nonsteroidal anti-inflammatory drugs, antiplatelet agents, and other anticoagulants. These colonoscopies often involve polypectomy, which can be complicated by bleeding. The risks of precipitating thromboembolic complications if anticoagulants are stopped must be weighed against the risk of postpolypectomy bleeding if these agents are continued. This article systematically reviews the management of anticoagulation during elective and emergency colonoscopy. For patients undergoing colonoscopic polypectomy, the overall risk of postpolypectomy bleeding is <0.5%. Risk factors for postpolypectomy bleeding include large polyp size and anticoagulant use, especially warfarin and thienopyridines. For patients who do not stop aspirin or other nonsteroidal anti-inflammatory drugs prior to colonoscopy, the rate of postpolypectomy bleeding is not significantly different from that for patients who do not take those medications. For patients who continue thienopyridines and undergo polypectomy, the risk of delayed postpolypectomy bleeding is approximately 2.4%. Even for patients who interrupt warfarin, the risk of postpolypectomy bleeding is increased. The direct oral anticoagulants (direct thrombin inhibitors and factor Xa inhibitors) have a rapid onset and offset of action, and periprocedural bridging generally is not necessary. For the thienopyridines, warfarin, and the direct oral anticoagulants, the decision to interrupt or continue these agents for endoscopy will involve considerable exercise of clinical judgment.

In vitro Research Concerning Effect of Clopidogrel Alone and on Combination with Aspirin and Dypiridamoleon Sedimentation of Erythrocytes

Based on extended theory of Derjaguin, Landau and Overbeeck (xDLVO) concerning aggregation of colloids and biological cells it was hypothesized that platelet antiaggregant agents have to reduce the aggregation of erythrocytes also. Applying Einstein-Stokes theory of sedimentation of spheres in viscous media it was concluded that sedimentation of erythrocytes is in fact sedimentation of aggregates of the approximately same size. Consequently, an expected outcome was that addition of antiaggregants in vitro to blood samples from patients with rheumatic or cardiovascular diseases will be the decrease of erythrocytes sedimentation. Starting from usual practice of dual antiaggregant therapy (aspirin and clopidogrel) effects of clopidogrel were compared with effects of clopidogrel plus small concentrations of aspirine and dipyridamole (smaller that their concentrations in plasma after in vivo administration) in order to put in evidence a possible synergic effect at platelet membrane level. Whole blood (0.8ml) was collected on 0.1ml 1% EDTA and then was added 25 or 50µl normal saline solution of clopidogrel or of the combination acetylosalycilic acid, clopidogrel and dypyridamole. The final concentrations were 1, 2 and µg/ml, of the same order as cumulated concentration of clopidogrel and its metabolites in clinical pharmacokinetics. Experiments were performed on a number of 40 human blood samples obtained from 2 groups of 20 patients. Sedimentation of erythrocytes was recorded using a camera and captured data were stored on a computer. Global analysis evidenced that in presence of antiaggregants the clusters of the sedimentation curves shifted down and into right, indicating a decrease and delay of sedimentation. Initial slopes and extent of sedimentation decreased linearly on clopidogrel concentration within the 1-3µg/ml range. For comparison of mean curves corresponding to different clopidogrel concentrations it was applied a metric from biopharmacy: areas under plasma concentrations curves (AUC) of drugs. The areas under average sedimentation curves decreased linearly at clopidogrel concentration within the 1-3µg/ml range. The same experiments were performed and similar results were obtained with the triple antiaggregant combination (clopidogrel, acetylosalycilic acid and dipyridamole). Apparently, a synergism between the tested antiaggregants appeared at studied concentration but the number of data was not sufficient to prove the statistical significance of the difference between clopidogrel alone and in triple combination.

Structure-activity relationship studies for multitarget antithrombotic drugs

Thrombosis is a complex process involving multiple pathways. Currently, therapy relies on the combination of two or more antithrombotic drugs, showing that inhibiting more than one target provides benefits in the prevention and treatment of thrombosis. This review focuses on structure-activity relationship studies of molecules possessing multiple actions against thrombosis, namely, dual inhibitors of coagulation, dual inhibitors of coagulation and platelet aggregation, and also dual inhibitors of platelet aggregation. EP217609 has just entered clinical trials, which raise the expectations on the multitarget strategy to prevent or treat thrombosis.

Efficacy and safety of vorapaxar for the prevention of adverse cardiac events in patients with coronary artery disease: a meta-analysis

BACKGROUND

Coronary artery disease (CAD) is the leading cause of morbidity and mortality worldwide. Vorapaxar, a protease-activated receptor-1 (PAR-1) antagonist, is a novel antiplatelet agent that may provide us a new way in antithrombotic therapy. Several studies had been conducted to evaluate the efficacy of vorapaxar in the treatment of CAD, but the results were inconsistent. Here a meta-analysis was made to assess the efficacy and safety of vorapaxar in reducing adverse cardiac events in patients with CAD.

METHODS

A comprehensive literature search was conducted. The primary efficacy endpoint was the major adverse cardiac events, which was defined as a composite of cardiovascular death, myocardial infarction (MI), stroke, urgent coronary revascularization, or recurrent ischemia with rehospitalization. The primary safety endpoint was the composite of major or minor bleeding events. Pooled effects were measured by odds ratios (ORs) with 95% confidence intervals (CIs). A random-effect or fixed model was used in this meta-analysis.

RESULTS

Totally, 31,388 patients from four randomized controlled trials (RCTs) were included in this meta-analysis. Patients who took vorapaxar combined with standard dual anti-platelet therapy (aspirin and thienopyridine) showed a lower incidence in major adverse cardiac events (OR, 0.86, 95% CI: 0.75-0.99, P=0.03), MI (OR, 0.79, 95% CI: 0.67-0.95, P=0.01) and ischemic stroke (OR, 0.72, 95% CI: 0.58-0.89, P=0.003) than those who only took placebo instead. But there was no significant reduction in cardiovascular death (OR, 0.95, 95% CI: 0.82-1.09, P=0.45). Nevertheless, the vorapaxar group were associated with a higher risk of bleeding events (P<0.001).

CONCLUSIONS

The result of this meta-analysis indicated that adding vorapaxar to the standard dual anti-platelet therapy may be efficient in reducing the incidence of major adverse cardiac events at the cost of increasing risk of bleeding events.

[Neurosurgery in a patient on dual antiplatelet therapy. Case report and the review of the literature]

INTRODUCTION

A neurosurgical intervention in a patient on dual antiplatelet therapy is a serious challenge for both the neurosurgeon and anesthesiologist..

MATERIAL AND METHODS

The article describes a clinical case of a successful urgent neurosurgical intervention (ventriculoperitoneostomy for obstructive hydrocephalus caused by a large meningioma of the posterior surface of the petrous pyramid) in a patient on dual antiplatelet therapy (DAT) due to a recently placed coronary stent..

CONCLUSION

Given a high risk of coronary stent thrombosis, the surgery was performed in the presence of ongoing DAT. There were no intracranial hemorrhagic complications, but subcutaneous hemorrhagic complications developed. The article discusses the features of managing similar patients whose number is growing.

Efficacy and safety of cilostazol based triple antiplatelet treatment versus dual antiplatelet treatment in patients undergoing coronary stent implantation: an updated meta-analysis of the randomized controlled trials

The aim of this study was to obtain best estimates of the efficacy and safety of cilostazol-based triple antiplatelet therapy (TAPT: aspirin, clopidogrel and cilostazol) compared with dual antiplatelet therapy (DAPT: aspirin and clopidogrel) in patients undergoing coronary stent implantation. We searched the literature to identify all randomized clinical trials examining efficacy and safety of TAPT versus DAPT in patients undergoing coronary stent implantation. Major efficacy outcomes were death, non-fatal myocardial infarction (MI), ischemic stroke and stent thrombosis (ST) and the safety outcome was bleeding. Data were analyzed using the Review Manager 5.0.0 software. A total of 19 trials involving 7,464 patients were included. TAPT and DAPT were associated with similar rates of death, non-fatal MI, ischemic stroke and ST, but compared with DAPT, TAPT had lower rates of target lesion revascularization (TLR) (RR 0.67, 95 % CI 0.56-0.82, P < 0.0001) and target vessel revascularization (TVR) (RR 0.65, 95 % CI 0.55-0.77, P < 0.00001), as well as less late loss of minimal lumen diameter (mean difference -0.14, 95 % CI -0.17--0.11, P < 0.00001), and less binary angiographic restenosis (RR 0.54, 95 % CI 0.45-0.65, P < 0.00001). TAPT and DAPT had similar rates of bleeding, but TAPT had significantly higher rates of headache, palpitation, rash and gastrointestinal side-effects. Cilostazol-based TAPT compared with DAPT is associated with improved angiographic outcomes and decreased risk of TLR and TVR but does not reduce major cardiovascular events and is associated with an increase in minor adverse events.

Dental extraction in patients receiving dual antiplatelet therapy

Background

Dual anti platelet therapy consists of administering antiplatelet (antiaggregant) drugs (clopidogrel and aspirin) to prevent thrombotic processes, as a preventative measure in patients with acute coronary disease, or in patients subjected to percutaneous coronary intervention.

Objectives

The purpose of this study was to evaluate the efficacy of a protocol for performing dental extraction in patients receiving dual anti platelet therapy.

Material and Methods

Thirty-two patients undergoing dental extractions were included in the study. The variables evaluated were: collagen-epinephrine fraction, collagen- adenosine diphosphate fraction, surgical surface, post-surgical measures, and adverse effects. Alveolar sutures and gauzes impregnated with an antifibrinolytic agent (tranexamic acid), which the patient pressed in place for 30 minutes, were applied to all patients as post-surgical measures. Descriptive statistics were calculated and analyzed with Student’s t-test to compare pairs of quantitative variables; simple regression analysis was performed using Pearson’s correlation coefficient. Statistical significance was set at p<0.05.

Results

Collagen/epinephrine fraction was 264.53±55.624 seconds with a range of 135 to 300 seconds, and collagen/ADP fraction was 119.41±44.216 seconds, both values being higher than normal. As a result of the post-surgical measures taken, no patients presented postoperative bleeding, hematoma or infection.

Conclusions

Dental extraction was safe for patients receiving dual anti-platelet therapy when using sutures and gauze impregnated with tranexamic acid, which the patient pressed in place for 30 minutes.

Key words: Aspirin, clopidogrel, tranexamic acid, dental extraction, platelet function.

Adverse cardiovascular outcomes in relation to suboptimal antithrombotic therapy use in patients undergoing peripheral artery disease angioplasty: lost opportunities?

INTRODUCTION

Current guidelines recommend antithrombotic therapy with either aspirin or clopidogrel for all patients with peripheral arterial disease (PAD). Nevertheless, cardiovascular comorbidities and perceived bleeding risk complicate antithrombotic management of PAD patients. We studied the proportion of patients receiving optimal (guideline-recommended) antithrombotic therapy, and second, assessed the impact of suboptimal antithrombotic therapy use to long-term outcomes of PAD patients.

METHODS

We performed a single centre retrospective analysis of patients with significant PAD, requiring percutaneous intervention. All patients coded as undergoing peripheral artery percutaneous transluminal angioplasty (PTA) between January 2007 and December 2011 were reviewed. Antithrombotic medication on discharge postprocedure was recorded.

RESULTS

Across the study period, 473 patients were coded as having received a PTA, but yet only 336 (71%) had data available for review: 218 (35.2%) male, mean age 73 ± 11 years. Of the whole cohort, 236 (70.2%) were discharged on optimal (guideline-recommended) antithrombotic therapy, 30 (8.9%) were considered 'overtreated' and 70 (20.8%) were undertreated. On multivariate analysis, patients with heart failure were more likely to be undertreated (OR 2.38, 95% CI: 1.15-5.00, p = 0.02) while patient with coronary artery disease were more likely to be overtreated (OR 4.00, 95% CI: 1.61-10.00, p = 0.03). Undertreated patients had an increased risk for all-cause mortality [hazard ratio (HR) 2.96, 95% CI 1.81-4.82: p = 0.00001] and cardiovascular mortality (HR 3.16, 95% CI: 1.49-6.68, p = 0.003).

CONCLUSION

In this single centre cohort of patients undergoing PTA, suboptimal antithrombotic therapy was not uncommon and had a major impact on long-term outcomes, resulting in increased all cause and cardiovascular mortality.

Yerba mate (Ilex paraguariensis) improves microcirculation of volunteers with high blood viscosity: a randomized, double-blind, placebo-controlled trial

BACKGROUND

Elevated blood viscosity is a risk factor for atherosclerosis, thrombosis and other cardiovascular events. Our previous studies have suggested that consumption of Yerba mate tea (Ilex paraguariensis) has strong antioxidant and lipid-lowering properties in animals. The in vivo effects of Yerba mate on blood viscosity in humans, however, have not been studied.

OBJECTIVE

This study aims to investigate the effect of Yerba mate tea on the reduction of blood viscosity and the improvement of microcirculatory parameters commonly regarded as risk factors for serious cardio and cerebrovascular disorders.

METHODS

142 subjects with high blood viscosity were recruited in this randomized, double-blind, placebo-controlled study. Yerba mate tea or placebo (5 g/day) was administered to different groups for 6 weeks. After treatment, results of hemorheological indexes, nailfold microcirculation, 6-keto-PGF1α and TXB2 and lipid profiles of subjects in the Yerba mate tea group were compared with those in the placebo-receiving group.

RESULTS

Parameters of blood viscosity and microcirculation were improved in the subjects from the Yerba mate tea group but not in placebo-receiving patients. After treatment, whole blood viscosity, plasma viscosity and the Equation K value of erythrocyte sedimentation rate (ESRK) decreased significantly in the Yerba mate group. Meanwhile, shape, flow state and nailfold microcirculation appeared positively changed. Specifically, blood flow speeds accelerated gradually and nailfold weighted integral values decreased significantly. Moreover, the vasodilator 6-keto PGF1α increased while the thromboxane TXB2 decreased in serum samples of subjects in the Yerba mate-receiving group. Overall, Yerba mate tea-receiving subjects saw nearly all measured values improve to levels comparable to those characteristic of patients with normal microcirculation.

CONCLUSIONS

These results indicate the therapeutic capacity of Yerba mate tea in the treatment of high blood viscosity. Here, Yerba mate tea played a role in the regulation of various indexes of hemorheology, nailfold microcirculation, and the platelet aggregating factors 6-keto-PGF1a and TXB2. The regulation of these might be correlated with reduced blood viscosity and accelerating blood flow. Thus, Yerba mate tea may reduce some key risk-factors of cardiovascular disease. Daily consumption of Yerba mate tea may be a better-tolerated option for individuals with high blood viscosity and microcirculatory disturbance and as such, a novel preventative strategy for patients at-risk for vascular disease.

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.

Low rate of postpolypectomy bleeding among patients who continue thienopyridine therapy during colonoscopy

BACKGROUND & AIMS

It is not clear whether the cardiovascular risk of discontinuing treatment with antiplatelet agents, specifically the thienopyridines, before elective colonoscopy outweighs the risks of postpolypectomy bleeding (PPB). We studied the rate of PPB in patients who continue thienopyridine therapy during colonoscopy.

METHODS

We performed a prospective study of 516 patients not taking warfarin who received polypectomies during elective colonoscopies; 219 were receiving thienopyridines, and 297 were not (controls). The occurrence of immediate PPB and delayed PPB was recorded. Delayed PPB was categorized as clinically important if it resulted in repeat colonoscopy, hospitalization, or blood transfusion.

RESULTS

Patients receiving thienopyridines were older and had significantly more comorbid diseases than controls; the mean number of polyps removed per patient was significantly higher (3.9 vs 2.9) in the thienopyridine group. Immediate PPB developed in 16 patients in the thienopyridine group (7.3%) and in 14 in the control group (4.7%, P = .25). Among patients who completed a 30-day follow-up analysis (96% of patients enrolled), clinically important, delayed bleeding occurred in 2.4% of patients receiving thienopyridines and in none of the controls (P = .01). All PPB events in both groups were resolved without surgery, angiography, or death.

CONCLUSIONS

Although a significantly higher percentage of patients who continue thienopyridine therapy during colonoscopy and polypectomy develop clinically important delayed PPB than patients who discontinue therapy, the rate of PPB events is low (2.4%), and all are resolved without sequelae. The risk for catastrophic cardiovascular risks among patients who discontinue thienopyridine therapy before elective colonoscopies could therefore exceed the risks of PPB. ClinicalTrials.gov, Number NCT01647568.

Clopidogrel has no effect on mortality from hip fracture

Over 76,000 patients in the UK sustain a proximal femoral fracture. Clopidogrel is currently the world's second best selling drug. There has been much recent controversy surrounding the optimal time for surgical intervention in this medically challenging group of patients. This consecutive series of 1225 patients from our unit over six years included thirty patients concurrently taking clopidogrel whilst sustaining a hip fracture. Our study demonstrated no significant difference in ASA grade, intra-operative blood loss or subsequent transfusion, post-operative wound complication, or mortality to one year in those taking clopidogrel. The authors therefore advocate timely surgical intervention as rapidly as circumstances allow.

Spontaneous spinal epidural haematoma after antiplatelet treatment: a report of two cases

We report 2 cases of spontaneous spinal epidural haematoma after antiplatelet treatment. One patient was on ticlodipine therapy and the other was on aspirin and clopidogrel. Both diagnoses were made using magnetic resonance imaging. One patient underwent multilevel laminectomies and posterior spinal fusion within 24 hours of symptom onset and achieved complete neurological recovery. The other underwent unilateral hemilaminectomies 40 hours after symptom onset and did not show neurological improvement. A high index of suspicion is needed for patients presenting with severe lower back pain and rapid neurological deterioration, especially in those on antiplatelet therapy. Urgent spinal cord decompression and epidural haematoma cord evacuation may provide more favourable outcome.

Dual Antiplatelet Agent—Induced Spontaneous Liver Hematoma

OBJECTIVE:

To report a case of a spontaneous liver hematoma in a patient receiving dual antiplatelet therapy for 5 years after coronary stent implantation.

CASE SUMMARY:

A 76-year-old man with coronary artery disease presented to the hospital with acute right upper quadrant pain. He had been taking clopidogrel 75 mg/day, a P2Y12 inhibitor, and aspirin 81 mg/day for 5 years after having a drug-eluting stent (DES) placed. Given a drop in hemoglobin (from 13.0 g/dL to 8.6 g/dL) and elevated liver enzymes, subsequent studies were performed and revealed a large liver hematoma. Clopidogrel and aspirin were discontinued. Aspirin was restarted 1 month later; there was no recurrence of bleeding.

DISCUSSION:

Current guidelines recommend that a P2Y12 inhibitor and aspirin after DES implantation be given for at least 12 months. However, because of concern for late stent thrombosis, some clinicians encourage patients to continue taking dual antiplatelet therapy beyond this period as long as the risk of bleeding is low. An objective causality assessment suggested that the liver hematoma was possibly related to the combination of clopidogrel and aspirin. To our knowledge, this is the first report of a patient who developed a liver hematoma while on aspirin and clopidogrel. Some recent studies have shown that the use of dual antiplatelet therapy for longer than 12 months does not reduce the rate of myocardial infarction or death from cardiac cause compared with aspirin monotherapy.

CONCLUSIONS:

It may be safer to maintain dual antiplatelet therapy for no more than 12 months after DES placement.

Whole blood viscosity issues VI: Association with blood salicylate level and gastrointestinal bleeding

Background:

This series on whole blood viscosity issues has been trying to elucidate the sensitivity, specificity and usefulness of the laboratory parameter in clinical practice. The postulation has been that since antiplatelet is used in the management of stasis, of which blood viscosity is an index, the latter would be useful laboratory indication and/or contraindication.

Aim:

The aim of this study was to observe whether blood level of acetylsalicylic acid differs with the level of whole blood viscosity.

Patients and Methods:

Out of the ten years database, 538 cases that were concomitantly tested for haematocrit, total proteins and blood level of salicylate were selected for this study. A separate nine cases of positive faecal occult blood tests were audited for blood viscosity and reviewed.

Results:

A statistically significant difference is observed with lower blood viscosity being associated with higher salicylate level in comparison of the former between the highest vs. lowest quartiles (p < 0.002). This observation demonstrates the effect of aspirin in lowering blood stasis. Reviewing the positive faecal occult blood cases indicate that gastrointestinal bleeding is characterized by relative hypoviscosity and that hyperviscosity is not present during bleeding complications.

Conclusion:

The findings affirm that whole blood viscosity is a valid clinical laboratory parameter for evidence-based contraindication, indication and monitoring of antiplatelet medication. It calls for better appreciation and clinical utility of whole blood viscosity, which (in the absence of viscometer) can now be extrapolated from haematocrit and total proteins.

Intracranial stents for treatment of acute ischemic stroke: evolution and current status

BACKGROUND

Intravascular stents have been applied to treat a variety of pathophysiologic conditions. With advances in stent design and delivery, stenting has become a viable treatment option in neurovascular disease. Recently, intracranial arterial stenting has received increasing interest as a modality to rapidly and effectively recanalize affected vessels in the setting of acute ischemic stroke.

METHODS

To examine the potential of stenting procedures for stroke, we compiled and analyzed relevant experimental and clinical studies in the available databases.

RESULTS

Our resulting discussion covers the brief history of stents, from their initial inception in the 1960s, to the developments of interventional cardiology, and finally to the treatment of acute occlusions of the neurovasculature. We also detail technological advances that have improved stent delivery to intracranial arteries and review the several clinical studies that feature stenting for the treatment of acute ischemic stroke.

CONCLUSION

Numerous clinical studies have revealed that stents are a quick and efficacious endovascular tool for acute ischemic stroke treatment. It appears likely that issues regarding design, safety, and feasibility of stent-based devices will experience further improvement and refinement, and from fruitful criticism of existing technologies and techniques, along with lessons from past mistakes, will arise safer and more effective devices.

Perioperative assessment of platelet function in patients under antiplatelet therapy

Platelets play a central role in primary hemostasis. Analysis of platelet function is therefore a cornerstone in the global assessment of the coagulation status in the perioperative setting, primarily in patients receiving antiplatelet medication, such as cyclooxygenase-1 inhibitors, adenosine diphosphate antagonists and glycoprotein IIb/IIIa inhibitors. In these patients, knowledge of residual platelet function is highly warranted in order to maintain an optimal and individual balance perioperatively between platelet function and inhibition - that is, bleeding and thrombosis. Traditional laboratory-based assays, such as light-transmission aggregometry and flow cytometry, are the clinical standards of platelet function testing today. Light-transmission aggregometry is one of the most widely used tests to identify and diagnose defects in platelet function. The majority of the conventional laboratory-based techniques are labor intensive, costly and time consuming, and require a high degree of experience and expertise to perform and interpret. Therefore, new automated technologies have been developed to measure platelet function more rapidly and easily, and several techniques can be used at the bedside, including whole blood aggregometry, high shear-induced platelet function assessment or viscoelastic measurement techniques. All methods assessing platelet function are summarized and their limitations are discussed in this article, emphasizing their perioperative use.

Realities and expectations of pharmacogenomics and personalized medicine: impact of translating genetic knowledge into clinical practice

The implementation of genetic data for a better prediction of response to medications and adverse drug reactions is becoming a reality in some clinical fields. However, to be successful, personalized medicine should take advantage of an informational structured framework of genetic, phenotypic and environmental factors in order to provide the healthcare system with useful tools that can optimize the effectiveness of specific treatment. The impact of personalized medicine is potentially enormous, but the results that have so far been gathered are often difficult to translate into clinical practice. In this article we have summarized the most relevant applications of pharmacogenomics on diseases to which they have already been applied and fields in which they are currently emerging. The article provides an overview of the opportunities and shortcomings of the implementation of genetic information into personalized medicine and its full adoption in the clinic. In the second instance, it provides readers from different fields of expertise with an accessible interpretation to the barriers and opportunities in the use/adoption of pharmacogenomic testing between the different clinical areas.

Elective single-vessel percutaneous coronary intervention in a vegetative state patient

A 73-year-old male in a persistent vegetative state underwent percutaneous coronary intervention (PCI) for unstable angina with multiple-vessel stenosis. The maximum dose pharmaceutical therapy was ineffective in controlling his symptoms. The goal of the procedure was to alleviate the patient's severe chest pain and vomiting with minimal invasion and risk. The procedure was effective despite treating only the culprit artery. Symptoms disappeared immediately after PCI and the patient remained attack free for 12 months. With the consent of the patient's family and support of medical staff, elective single-vessel PCI can be a practical and effective treatment option for refractory angina in patients with impaired consciousness.

Physicians' attitudes toward post-MI aspirin prophylaxis: findings from an online questionnaire in Europe and Latin America

Few surveys have assessed physicians' attitudes toward preventive treatment in post-myocardial infarction (MI) patients, although these patients have a high risk of recurrence. A newly developed online survey, which aimed to determine physicians' attitudes toward aspirin prophylaxis post-MI, was sent to physicians in 18 countries. This report describes findings from 7 European (n = 2842 respondents) and 2 Latin American (n = 149 respondents) countries. Although low-dose aspirin therapy was recommended by most physicians (> 90%), compliance was suboptimal; 29% of patients in Europe and 35% in Latin America were partially or totally noncompliant, and 18% of physicians in Europe and 20% in Latin America had lost contact with their patients. Low-dose aspirin monotherapy or combination therapy, dosage, and physician contact all had a significant effect on compliance (P < 0.00001). Shared decision making by the physician and patient was rated as the most effective measure to improve compliance, which clearly indicates the need for a change in management.

Temporary endovascular bypass: a novel treatment for acute stroke

Intracranial stent placement is emerging as an effective treatment for acute stroke. As a means to avoid stent-associated complications and capitalize on stent-placement-related advantages, the concept of a "temporary endovascular bypass" (TEB) for stroke therapy was recently reported. In this technique, a stent is temporarily deployed for instant recanalization. Once sufficient flow is established to maintain vessel patency, the stent is recaptured and withdrawn. We report a second case to further characterize the merits of TEB.

Effects of Aspirin on Clot Structure and Fibrinolysis Using a Novel In Vitro Cellular System

Objectives— The purpose of this study was to investigate the direct effects of aspirin on fibrin structure/function.

Methods and Results— Chinese Hamster Ovary cell lines stably transfected with fibrinogen were grown in the absence (0) and presence of increasing concentrations of aspirin. Fibrinogen was purified from the media using affinity chromatography, and clots were made from recombinant protein. Mean final turbidity [OD(±SEM)] was 0.083(±0.03), 0.093(±0.002), 0.101(±0.005), and 0.125(±0.003) in clots made from 0, 1, 10, and 100 mg/L aspirin-treated fibrinogen, respectively ( P <0.05). Permeability coefficient (Ks cm 2 ×10 −8 ) was 1.68(±0.29) and 4.13(±0.33) comparing fibrinogen produced from cells grown with 0 mg/L and 100 mg/L aspirin respectively ( P <0.05). Scanning electron microscopy confirmed a looser clot structure and increased fiber thickness of clots made from aspirin-treated fibrinogen, whereas rheometer studies showed a significant 30% reduction in clot rigidity. Fibrinolysis was quicker in clots made from aspirin-treated fibrinogen. Ex vivo studies in 3 normal volunteers given 150 mg aspirin daily for 1 week demonstrated similar changes in clot structure/function.

Conclusion— Aspirin directly altered clot structure resulting in the formation of clots with thicker fibers and bigger pores, which are easier to lyse. This study clearly demonstrates an alternative mode of action for aspirin, which should be considered in studies evaluating the biochemical efficacy of this agent.

2007 Guideline update for unstable angina/non-ST-segment elevation myocardial infarction: focus on antiplatelet and anticoagulant therapies

OBJECTIVE

To summarize key changes in the 2007 American College of Cardiology/American Heart Association (ACC/AHA) guideline recommendations for pharmacologic therapy as they relate to antiplatelets and anticoagulants, and to evaluate the evidence from several landmark trials that was used to support the guideline updates for these agents.

DATA SOURCES

Literature was accessed through MEDLINE (1950-January 2008) using the search terms acute coronary syndromes, unstable angina (UA), non-ST-segment elevation myocardial infarction (NSTEMI), antiplatelet, and anticoagulant. All papers were cross-referenced to identify additional studies.

STUDY SELECTION AND DATA EXTRACTION

ACC/AHA guidelines, relevant original research articles, and review articles were evaluated. Studies with more than 1000 patients were the focus of the review.

DATA SYNTHESIS

UA and NSTEMI are the most common presentations of acute coronary syndrome. The recently updated ACC/AHA guidelines for management of this condition were based on significant advances in pharmacotherapy including expanded use of drug-eluting stents, pretreatment with clopidogrel, and newer anticoagulants such as bivalirudin and fondaparinux. Landmark trials have been published that describe advances in the use of antiplatelets and anticoagulants. According to the guidelines, unfractionated heparin (UFH) and enoxaparin are preferred options for both invasive and conservative management. Enoxaparin was noninferior to UFH for invasive management in the SYNERGY trial, although it was associated with a higher incidence of bleeding. Other alternatives for an invasive strategy per the guidelines include bivalirudin and fondaparinux. Bivalirudin (alone or with glycoprotein [GP] IIb/IIIa inhibitor) was compared with heparin plus GP IIb/IIIa inhibitor in the ACUITY trial of patients undergoing early invasive management. The bivalirudin groups were noninferior to standard of care, although bivalirudin alone was associated with less bleeding. Fondaparinux was found to be noninferior to enoxaparin and was associated with fewer bleeding events in the OASIS-5 study of patients who were not treated with an early invasive approach. Accordingly, the guidelines 1list fondaparinux as an alternative for a conservative strategy or in patients at increased risk of bleeding.

CONCLUSIONS

Clinicians should be familiar with the updated 2007 ACC/AHA guidelines and the clinical trial evidence that serves as the basis for these recommendations. It is paramount for institutions to outline a preferred and consistent treatment approach. These decisions should involve a review of established efficacy, bleeding risk, need for anticoagulant reversal, costs, and clinician familiarity with different treatment regimens.