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Impact of a Computerized Antithrombotic Risk Assessment Tool on the Prescription of Thromboprophylaxis in Atrial Fibrillation: Hospital Setting.
Pandya, E, Masood, N, Wang, Y, Krass, I, Bajorek, B
Clinical and applied thrombosis/hemostasis : official journal of the International Academy of Clinical and Applied Thrombosis/Hemostasis. 2018;(1):85-92
Abstract
The computerized antithrombotic risk assessment tool (CARAT) is an online decision-support algorithm that facilitates a systematic review of a patient's stroke risk, bleeding risk, and pertinent medication safety considerations, to generate an individualized treatment recommendation. The CARAT was prospectively applied across 2 hospitals in the greater Sydney area. Its impact on antithrombotics utilization for thromboprophylaxis in patients with nonvalvular atrial fibrillation was evaluated. Factors influencing prescribers' treatment selection were identified. The CARAT recommended a change in baseline therapy for 51.8% of patients. Among anticoagulant-eligible patients (ie, where the risk of stroke outweighed the risk of bleeding) using "nil therapy" or antiplatelet therapy at baseline, the CARAT recommended an upgrade to warfarin in 60 (30.8%) patients. For those in whom the bleeding risk outweighed the stroke risk, the CARAT recommended a downgrade from warfarin to safer alternatives (eg, aspirin) in 37 (19%) patients. Among the "most eligible" (ie, high stroke risk, low bleeding risk, no contraindications; n = 75), the CARAT recommended warfarin for all cases. Discharge therapy observed a marginal increase in anticoagulation prescription in eligible patients (n = 116; 57.8% vs 64.7%, P = .35) compared to baseline. Predictors of warfarin use (vs antiplatelets) included congestive cardiac failure, diabetes mellitus, and polypharmacy. The CARAT was able to optimize the selection of therapy, increasing anticoagulant use among eligible patients. With the increasing complexity of decision-making, such tools may be useful adjuncts in therapy selection in atrial fibrillation. Future studies should explore the utility of such tools in selecting therapies from within an expanded treatment armamentarium comprising the non-vitamin K antagonist oral anticoagulants.
2.
Increased risk of atherothrombotic events associated with cytochrome P450 3A5 polymorphism in patients taking clopidogrel.
Suh, JW, Koo, BK, Zhang, SY, Park, KW, Cho, JY, Jang, IJ, Lee, DS, Sohn, DW, Lee, MM, Kim, HS
CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne. 2006;(12):1715-22
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Abstract
BACKGROUND Clopidogrel is a prodrug requiring metabolism by cytochrome P450 3A (CYP3A) isoenzymes, including CYP3A5, in order to be active. It is controversial whether clopidogrel interacts with CYP3A inhibitors. We investigated the influence of CYP3A5 polymorphism on the drug interaction of clopidogrel. METHODS In phase 1 of the study, we administered clopidogrel to 16 healthy volunteers who had the CYP3A5 non-expressor genotype (*3 allele) and 16 who had the CYP3A5 expressor genotype (*1 allele) with and without pretreatment with itraconazole, a potent CYP3A inhibitor. A platelet aggregation test was performed at baseline, 4 hours, 24 hours and 6 days after clopidogrel administration. In phase 2, we compared clinical outcomes of 348 patients treated with clopidogrel after successful coronary angioplasty with bare-metal stent implantation according to their CYP3A5 genotype; the primary end point was a composite of atherothrombotic events (cardiovascular death, myocardial infarction and non-hemorrhagic stroke) within 1 and 6 months after stent implantation. RESULTS In phase 1, the change in platelet aggregation after clopidogrel administration and pretreatment with itraconazole was greater among the subjects with the CYP3A5 expressor genotype than among those with the non-expressor genotype: 24.9% (standard deviation [SD] 13.9%) v. 6.2% (SD 13.5%) at 4 hours (p < 0.001); 27.7% (SD 16.5%) v. 2.5% (SD 8.3%) at 24 hours (p < 0.001); and 33.5% (SD 18.6%) v. 17.8% (SD 13.8%) at day 7 (p < 0.01). In phase 2, atherothrombotic events occurred more frequently within 6 months after stent implantation among the patients with the non-expressor genotype than among those with the expressor genotype (14/193 v. 3/155; p = 0.023). Multivariable analysis showed that the CYP3A5 polymorphism was a predictor of atherothrombotic events in clopidogrel users. INTERPRETATION People with the CYP3A5 non-expressor genotype are vulnerable to drug interactions between clopidogrel and CYP3A inhibitors. This phenomenon may be associated with worse outcomes in patients with the non-expressor genotype who are given clopidogrel after coronary angioplasty and implantation of bare-metal stents.
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Heparin-coated Wiktor stents in human coronary arteries (MENTOR trial). MENTOR Trial Investigators.
Vrolix, MC, Legrand, VM, Reiber, JH, Grollier, G, Schalij, MJ, Brunel, P, Martinez-Elbal, L, Gomez-Recio, M, Bär, FW, Bertrand, ME, et al
The American journal of cardiology. 2000;(4):385-9
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Abstract
The purpose of this study was to determine the feasibility, safety, and efficacy of elective stenting with heparin-coated Wiktor stents in patients with coronary artery disease. In experimental studies, heparin coating has been shown to prevent subacute thrombosis and restenosis. Recently, a new method of heparin coating was developed, resulting in a more stable and predictable heparin layer on stent devices. This trial constitutes the first in-human use of this coating procedure, applied on the well-known Wiktor stent device. Heparin-coated Wiktor stent implantation was performed in 132 consecutive patients (132 lesions) in a multicenter international trial from September 1996 to February 1997. Forty-three percent of patients had unstable angina, 33% had previous myocardial infarction, and 10% had diabetes mellitus. Patients were followed for 12 months for occurrence of major adverse cardiovascular events, and 96% of the eligible patients underwent quantitative angiographic control at 6 months. Stent deployment was successful in 95.5% of lesions. Minimal lumen diameter increased by 1.67 +/- 0.48 mm (from 1.02 +/- 0.38 mm before to 2.69 +/- 0.37 mm after the stent implantation). Mean percent diameter stenosis decreased from 67.4 +/- 11.3% before to 18.9 +/- 7.7% after the intervention. A successful intervention (<50% diameter stenosis and no major adverse cardiac events within 30 days) occurred in 97% of the patients. The subacute thrombosis rate was 0.8%, which compares favorably with historical controls of this stent, and a low incidence of postprocedural increase in creatine kinase-MB was noted. At 6 months, event-free survival was 85% and angiographic restenosis rate was 22% with late loss of 0.78 +/- 0.69 mm and a loss index of 0.48 +/- 0.44. Heparin-coated Wiktor stents appeared to be an efficacious device to treat Benestent-like lesions, yielding angiographic and clinical results comparable to a heparin-coated Palmaz-Schatz stent. Despite its use in more complex lesions, the incidence of subacute thrombosis appeared to be lower than historical controls with a similar noncoated stent.