The safety and efficacy of aspirin and clopidogrel as a combination treatment in patients with coronary heart disease

The safety of upper gastrointestinal endoscopic biopsy in patients receiving antithrombic drugs. A single-centre prospective observational study

Introduction

In July 2012, the Japan Gastroenterological Endoscopy Society updated their guidelines on gastroenterological endoscopy in patients undergoing antithrombotic therapy, although the safety of endoscopic procedures in patients receiving antithrombotic drugs has yet to be sufficiently studied.

Aim

This study evaluates the safety of upper gastroenterological endoscopic biopsy in patients receiving antithrombotic drugs. We evaluated the prospective observational safety of endoscopic biopsy performed in the endoscopy unit of our patients using antithrombotic drugs.

Material and methods

Oesophagogastroduodenoscopies (OGD) and biopsies performed at a single endoscopy unit between July 2018 and February 2019 were examined in this prospective observational study. Patients receiving antithrombotic drugs due to cardiovascular and neurological reasons, who underwent an endoscopic mucosal biopsy for diagnostic purposes, were included in the study.

Results

The study was completed with 166 patients who underwent an endoscopic biopsy, from whom a total of 327 biopsies taken. The patients were examined in two groups: those “receiving antithrombotic drugs” and those who had “stopped taking antithrombotic drugs”. There was no statistically significant difference between the two groups with respect to bleeding.

Conclusions

This prospective observational study showed that performing an endoscopic biopsy without the cessation of antithrombotic drugs does not increase bleeding risk. Low-risk procedures, such as endoscopic mucosal biopsies, can be performed confidently by experienced endoscopists.

Ticagrelor Use in Indian Patients Undergoing Neuroendovascular Procedures: A Single Center Experience

PURPOSE

A safe and efficacious antiplatelet drug is needed for patients with clopidogrel resistance who undergo neuroendovascular procedures. Ticagrelor is a new reversibly binding, oral, direct-acting P2Y receptor antagonist with no known resistance. We describe our clinical experience using ticagrelor for neuroendovascular procedures in Indian patients with clopidogrel resistance at the NH Institute of Neurosciences, Narayana Health City, Bangalore.

MATERIALS AND METHODS

We retrospectively reviewed our endovascular procedure database for all patients with predefined clopidogrel resistance. Clopidogrel resistance was defined as P2Y12 inhibition <40%. Patients were administered ticagrelor along with aspirin prior to the procedure.

RESULTS

Of 127 patients, 32 (25%) were non-responders to clopidogrel (22 [69%] males, 10 [31%] females; median age, 54 years [range, 20-75]). All patients were treated with a 180-mg loading dose of ticagrelor, followed by 90 mg twice daily. Twenty patients (63%) underwent endovascular intervention for intracranial aneurysm, two (6%) for dissecting aneurysms, nine (28%) for stenotic lesions, and one (3%) for carotico-cavernous fistula. No patient experienced any adverse effects related to the use of Ticagrelor in the postoperative period.

CONCLUSION

Ticagrelor is an effective alternative to clopidogrel for use in conjunction with aspirin in patients with clopidogrel resistance. None of our patients had adverse effects from ticagrelor. Drug cost, twice-daily dosing, and risk of faster platelet aggregation activation after discontinuation should be taken into consideration prior to its use in such patients.

Safety of gastrointestinal endoscopic biopsy in patients taking antithrombotics

BACKGROUND AND AIM

Current Japanese gastrointestinal (GI) endoscopic guidelines permit endoscopic biopsy without cessation of antiplatelet agents and warfarin in patients with a therapeutic range of prothrombin time-international normalized ratio (PT-INR) levels, although the evidence levels are low. We evaluated the safety of endoscopic biopsy in patients currently taking antithrombotics.

METHODS

Consecutive patients receiving antithrombotics who underwent GI endoscopy from August 2012 to August 2013 were enrolled. Adverse events and endoscopic hemostasis after biopsy were evaluated. PT-INR level was measured in patients taking warfarin the day before endoscopy.

RESULTS

Among 7939 patients undergoing endoscopy, 1034 patients (13.0%, 706 men and 328 women, average age 72.8 years) were receiving antithrombotics. Antithrombotics included aspirin (44.8%), warfarin (34.7%), thienopyridine (16.1%), cilostazol (10.3%), dabigatran (4.8%) etc. PT-INR levels in patients taking warfarin were >3.0 in 13 patients (4.3%), between 2.5 and 3.0 in 18 patients (6.0%), <2.5 in 269 patients (89.7%). Two hundred and six patients received endoscopic biopsy while taking aspirin (51.2%), warfarin (22.8%), and thienopyridine (13.6%). Endoscopic hemostasis was required in three patients after endoscopic biopsy (spraying thrombin in two patients, spraying thrombin and clipping in one patient). There were no major complications. The incidence of endoscopic hemostasis after biopsy in patients without antithrombotic cessation was not significantly different than in the controls not taking antithrombotics (1.5% vs 0.98%, P = 0.51).

CONCLUSION

Endoscopic biopsy did not increase the bleeding risk despite not stopping antithrombotics prior to biopsy even among patients taking warfarin whose PT-INR was within the therapeutic range.

Novel single nucleotide polymorphism markers for low dose aspirin-associated small bowel bleeding

BACKGROUND

Aspirin-induced enteropathy is now increasingly being recognized although the pathogenesis of small intestinal damage induced by aspirin is not well understood and related risk factors have not been established.

AIM

To investigate pharmacogenomic profile of low dose aspirin (LDA)-induced small bowel bleeding.

METHODS

Genome-wide analysis of single nucleotide polymorphisms (SNPs) was performed using the Affymetrix DMET™ Plus Premier Pack. Genotypes of candidate genes associated with small bowel bleeding were determined using TaqMan SNP Genotyping Assay kits and direct sequencing.

RESULTS

In the validation study in overall 37 patients with small bowel bleeding and 400 controls, 4 of 27 identified SNPs: CYP4F11 (rs1060463) GG (p=0.003), CYP2D6 (rs28360521) GG (p=0.02), CYP24A1 (rs4809957) T allele (p=0.04), and GSTP1 (rs1695) G allele (p=0.04) were significantly more frequent in the small bowel bleeding group compared to the controls. After adjustment for significant factors, CYP2D6 (rs28360521) GG (OR 4.11, 95% CI. 1.62 -10.4) was associated with small bowel bleeding.

CONCLUSIONS

CYP4F11 and CYP2D6 SNPs may identify patients at increased risk for aspirin-induced small bowel bleeding.

Combination of low-dose aspirin and thienopyridine exacerbates small bowel injury

OBJECTIVE

Antithrombotics is increasingly being used for cardiovascular prevention. In more recent studies, small bowel injury and enteropathy associated with low-dose aspirin are increasingly being recognized. Aim of this study was to evaluate small bowel injury using video capsule endoscopy (VCE) in obscure gastrointestinal bleeding (OGIB) patients taking low-dose aspirin including other antithrombotics.

MATERIAL AND METHODS

This is a retrospective review of chronic users of antithrombotics who underwent VCE for suspected small bowel bleeding. Small bowel mucosal injury was evaluated using VCE findings.

RESULTS

Fifty-four OGIB patients (36 men and 18 women, mean age 72.4 years) underwent VCE from January 2007 to May 2009. Twenty-two patients were taking 100 mg of enteric-coated aspirin (aspirin group), 8 taking thienopyridine, (ticlopidine or clopidogrel, thienopyridine group), 13 taking aspirin combined with thienopyridine (combined group), and 11 taking warfarin (warfarin group). The mucosal injury, especially ulcers were most frequently detected in the combined group (46.2%, p = 0.01) among the four groups. The median number of redness lesions in the combined group was the highest among the four groups and was significantly higher than that in the warfarin group. The lesions of redness or small erosions in the aspirin and the combined groups tended to exist in the proximal part of small bowel.

CONCLUSIONS

Combination of low-dose aspirin therapy and thienopyridine may exacerbate small bowel injury, and the preventive strategies should be established.

APD791, 3-methoxy-n-(3-(1-methyl-1h-pyrazol-5-yl)-4-(2-morpholinoethoxy)phenyl)benzamide, a novel 5-hydroxytryptamine 2A receptor antagonist: pharmacological profile, pharmacokinetics, platelet activity and vascular biology

We have evaluated the receptor pharmacology, antiplatelet activity, and vascular pharmacology of APD791 [3-methoxy-N-(3-(1-methyl-1H-pyrazol-5-yl)-4-(2-morpholinoethoxy)phenyl)benzamide] a novel 5-hydroxytryptamine 2A (5-HT(2A)) receptor antagonist. APD791 displayed high-affinity binding to membranes (K(i) = 4.9 nM) and functional inverse agonism of inositol phosphate accumulation (IC(50) = 5.2 nM) in human embryonic kidney cells stably expressing the human 5-HT(2A) receptor. In competition binding assays, APD791 was greater than 2000-fold selective for the 5-HT(2A) receptor versus 5-HT(2C) and 5-HT(2B) receptors, and was inactive when tested against a wide panel of other G-protein-coupled receptors. APD791 inhibited 5-HT-mediated amplification of ADP-stimulated human and dog platelet aggregation (IC(50) = 8.7 and 23.1 nM, respectively). Similar potency was observed for inhibition of 5-HT-stimulated DNA synthesis in rabbit aortic smooth muscle cells (IC(50) = 13 nM) and 5-HT-mediated vasoconstriction in rabbit aortic rings. Oral administration of APD791 to dogs resulted in acute (1-h) and subchronic (10-day) inhibition of 5-HT-mediated amplification of collagen-stimulated platelet aggregation in whole blood. Two active metabolites, APD791-M1 and APD791-M2, were generated upon incubation of APD791 with human liver microsomes and were also indentified in dogs after oral administration of APD791. The affinity and selectivity profiles of both metabolites were similar to APD791. These results demonstrate that APD791 is an orally available, high-affinity 5-HT(2A) receptor antagonist with potent activity on platelets and vascular smooth muscle.

Use of antiplatelet agents for prevention of ischemic stroke

Overall management to lower risk for ischemic stroke is multifaceted. Management includes measures to treat risk factors for accelerated atherosclerosis and stroke, antithrombotic therapies to lower the risk for thromboembolism, and surgery to treat a defined arterial or cardiac lesion. Treatment decisions are made on a case-by-case basis, with most patients receiving some combination of medication and recommendations for lifestyle modification. Some patients will also undergo surgical or endovascular interventions. This article discusses antithrombotic treatment for ischemic stroke prevention, placing major emphasis on the indications for and administration of antiplatelet therapy.

Targeting platelets for prevention and treatment of cardiovascular disease

Platelets play an important role in the development of thrombosis, atherosclerosis, hypertension, heart attack and stroke. As a result, pharmacologic interventions that influence platelet functions, such as adhesion, aggregation and the release of different factors, are considered useful for the prevention and treatment of cardiovascular disease. Although classical anti-platelet agents have proven beneficial effects for the treatment of some specific cardiovascular diseases, there are limitations for their use as these drugs target platelet function directly. In contrast, newly developed anti-platelet agents have broad applications for the treatment of cardiovascular disease as they not only influence platelet function but are also considered to affect cardiac and vascular smooth muscle cell functions. Natural food products and nutraceutical agents also appear to modify cardiovascular abnormalities by affecting various platelet functions; however, the mechanisms of their actions remain to be investigated. Accordingly, this article is focused to discuss emerging pharmacologic, nutritional and nutraceutical interventions that may influence the prevention or progression of a broad range of cardiovascular diseases.

Clinical aspects of platelet inhibitors and thrombus formation

The platelet, once thought to be solely involved in clot formation, is now known to be a key mediator in various others processes such as inflammation, thrombosis, and atherosclerosis. Supported by the wealth of evidence from clinical trials demonstrating their benefits in patient outcomes, antiplatelet agents have become paramount in the prevention and management of various diseases involving the cardiovascular, cerebrovascular, and peripheral arterial systems. Despite being among the most widely used and studied classes of medical therapies, new discoveries regarding important clinical aspects and properties of these agents continue to be made. As our understanding of platelet biology expands, more effective and safer novel therapies continue to be developed. The use of more refined agents in conjunction with a better understanding of their effects will further the ability to provide more optimized care on an individual basis.