OBJECTIVES: The aim of this study was to describe trends in warfarin dosing after Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG).
SETTING: Single academic center.
METHODS: All patients chronically on warfarin anticoagulation before RYGB or SG were retrospectively identified. Indications for anticoagulation, history of bleeding or thrombotic events, perioperative complications, and warfarin dosing were collected.
RESULTS: Fifty-three patients (RYGB n = 31, SG n = 22) on chronic warfarin therapy were identified (56.6% female, mean 54.4 ± 11.7 yr of age). Of this cohort, 34.0% had prior venous thromboembolic events, 43.4% had atrial fibrillation, and 5.7% had mechanical cardiac valves. Preoperatively, the average daily dose of warfarin was similar in the RYGB group (8.3 ± 4.1 mg) and SG group (6.9 ± 2.8 mg). One month after surgery, mean daily dose of warfarin was reduced 24.1% in the RYGB group (P
AREAS COVERED: A review of articles that evaluated the cost of prescribing conventional (e.g. vitamin K antagonists) and NOACs (e.g. direct thrombin inhibitors and direct factor Xa inhibitors) in older adults.
EXPERT COMMENTARY: While the use of NOACs significantly increases the cost of the initial treatment for thromboembolic disorders, they are still considered cost-effective relative to warfarin since they offer reduced risk of intracranial haemorrhagic events. The optimum anticoagulation with warfarin can be achieved by providing specialised care; clinics managed by pharmacists have been shown to be cost-effective relative to usual care. There are suggestions that genotyping the CYP2C9 and VKORC1 genes is useful for determining a more appropriate initial dose and thereby increasing the effectiveness and safety of warfarin.
METHODS: We performed a 3 × 2 partial factorial double-blind trial of 17,598 participants with stable cardiovascular disease and peripheral artery disease. Participants were randomly assigned to groups given pantoprazole 40 mg daily or placebo, as well as rivaroxaban 2.5 mg twice daily with aspirin 100 mg once daily, rivaroxaban 5 mg twice daily, or aspirin 100 mg alone. The primary outcome was time to first upper gastrointestinal event, defined as a composite of overt bleeding, upper gastrointestinal bleeding from a gastroduodenal lesion or of unknown origin, occult bleeding, symptomatic gastroduodenal ulcer or ≥5 erosions, upper gastrointestinal obstruction, or perforation.
RESULTS: There was no significant difference in upper gastrointestinal events between the pantoprazole group (102 of 8791 events) and the placebo group (116 of 8807 events) (hazard ratio, 0.88; 95% confidence interval [CI], 0.67-1.15). Pantoprazole significantly reduced bleeding of gastroduodenal lesions (hazard ratio, 0.52; 95% confidence interval, 0.28-0.94; P = .03); this reduction was greater when we used a post-hoc definition of bleeding gastroduodenal lesion (hazard ratio, 0.45; 95% confidence interval, 0.27-0.74), although the number needed to treat still was high (n = 982; 95% confidence interval, 609-2528).
CONCLUSIONS: In a randomized placebo-controlled trial, we found that routine use of proton pump inhibitors in patients receiving low-dose anticoagulation and/or aspirin for stable cardiovascular disease does not reduce upper gastrointestinal events, but may reduce bleeding from gastroduodenal lesions. ClinicalTrials.gov ID: NCT01776424.
METHODS: We searched PubMed, EMBASE and Cochrane library from inception to Feb 24th, 2017, to identify systematic reviews and meta-analyses of randomized controlled trials that assessed interventions or strategies to improve oral anticoagulant use in AF patients.
RESULTS: Thirty-four systematic reviews were eligible for inclusion but only 11 were included in the qualitative analyses, corresponding to 40 unique meta-analyses, as the remaining systematic reviews had overlapping primary studies. There was insufficient evidence to support the efficacy of genotype-guided dosing and pharmacist-managed anticoagulation clinics for stroke prevention in AF patients. Conversely, patient's self-management and novel oral anticoagulants (NOACs), in general were superior to warfarin for preventing stroke and reducing mortality. All interventions showed comparable risk of major bleeding with warfarin.
CONCLUSION: Findings from this overview support the superiority of NOACs and patient's self-management for preventing stroke in AF patients. However, uncertainties remain on the benefits of genotype-guided dosing and pharmacist-managed anticoagulation clinics due to poor quality evidence, and future research is warranted.
MATERIALS AND METHODS: Five Malay patients receiving warfarin maintenance therapy were investigated for their CYP2C9*2, CYP2C9*3, and VKORC1-1639G>A genotypes and their vitamin K-dependent (VKD) clotting factor activities. The records of their daily warfarin doses and international normalized ratio (INR) 2 years prior to and after the measurement of VKD clotting factors activities were acquired. The mean warfarin doses were compared with predicted warfarin doses calculated from a genotypic-based dosing model developed for Asians.
RESULTS: A patient with the VKORC1-1639 GA genotype, who was supposed to have higher dose requirements, had a lower mean warfarin dose similar to those having the VKORC1-1639 AA genotype. This discrepancy may be due to the coadministration of celecoxib, which has the potential to decrease warfarins metabolism. Not all patients' predicted mean warfarin doses based on a previously developed dosing algorithm for Asians were similar to the actual mean warfarin dose, with the worst predicted dose being 54.34% higher than the required warfarin dose.
CONCLUSION: Multiple clinical factors can significantly change the actual required dose from the predicted dose from time to time. The additions of other dynamic variables, especially INR, VKD clotting factors, and concomitant drug use, into the dosing model are important in order to improve its accuracy.
METHODS: In this retrospective study, we reviewed the cases diagnosed with CVST admitted to our centre from January 2011 until November 2015.
RESULTS: A total of 15 patients were included in this review. The patterns of imaging findings as well as risk factors for CVST is discussed with a review of the literature and current management practices. One year followed-up showed full recovery (Glasgow Outcome Scale (GOS) of 5) in 10 cases (66.7%), whereas 4 cases (26.7%) with GOS of 4 (three cases with neurological deficits, and 1 case with mild symptom. There was one case of mortality in this study secondary to sepsis during hospitalisation. The presenting symptoms were mainly headache, focal neurology deficits, seizure and altered sensorium. Risk factors identified were oral contraceptive pills usage, chronic sinuses or ear infections, and obesity. Initial computed tomography (CT) scan showed various findings and haemorrhagic infarct was one of the common findings. Magnetic resonance imaging (MRI) and magnetic resonance venography (MRV) revealed majority of the patients had occlusion at two or more venous sinus sites. No patients had new or recurrent intracranial haemorrhage following initiation of anticoagulation therapy.
CONCLUSION: Thus it is considerable safe to start anticoagulation therapy in CVST patients including those with intracranial haemorrhage. We propose further neuroimaging to avoid missed diagnosis of CVST in patient presented with recent onset headache and CT evidence of unusual cerebral infarction.
METHODS: An open-label, non-inferiority, 1:1 randomized trial was conducted at three academic hospitals in South East Asia, involving 322 ethnically diverse patients newly indicated for warfarin (NCT00700895). Clinical follow-up was 90 days. The primary efficacy measure was the number of dose titrations within the first 2 weeks of therapy, with a mean non-inferiority margin of 0.5 over the first 14 days of therapy.
RESULTS: Among 322 randomized patients, 269 were evaluable for the primary endpoint. Compared with traditional dosing, the genotype-guided group required fewer dose titrations during the first 2 weeks (1.77 vs. 2.93, difference -1.16, 90% CI -1.48 to -0.84, P
PURPOSE: The aim was to determine the metabolic fingerprint that predicts warfarin response based on the international normalized ratio (INR) in patients who are already receiving warfarin (phase I: identification) and to ascertain the metabolic fingerprint that discriminates stable from unstable INR in patients starting treatment with warfarin (phase II: validation).
EXPERIMENTAL APPROACH: A total of 94 blood samples were collected for phase I: 44 patients with stable INR and 50 with unstable INR. Meanwhile, 23 samples were collected for phase II: nine patients with stable INR and 14 with unstable INR. Data analysis was performed using multivariate analysis including principal component analysis and partial least square-discriminate analysis (PLS-DA), followed by univariate and multivariate logistic regression (MVLR) to develop a model to identify unstable INR biomarkers.
KEY RESULTS: For phase I, the PLS-DA model showed the following results: sensitivity 93.18%, specificity 91.49% and accuracy 92.31%. In the MVLR analysis of phase I, ten regions were associated with unstable INR. For phase II, the PLS-DA model showed the following results: sensitivity 66.67%, specificity 61.54% and accuracy 63.64%.
CONCLUSIONS AND IMPLICATIONS: We have shown that the pharmacometabonomics technique was able to differentiate between unstable and stable INR with good accuracy. NMR-based pharmacometabonomics has the potential to identify novel biomarkers in plasma, which can be useful in individualizing treatment and controlling warfarin side effects, thus, minimizing undesirable effects in the future.