vitamin-k-semiquinone-radical and Cerebrovascular-Disorders

Cerebral venous thrombosis (CVT) causes significant disability and mortality. Current guidelines for CVT management support the initial use of unfractionated heparin or low molecular weight heparin followed by longer-term oral vitamin K antagonist (VKA). There has been increasing, albeit limited, evidence for the use of direct oral anticoagulants (DOAC) as an alternative to VKA. We performed a systematic review and meta-analysis of studies that compared the safety and efficacy of DOACs to VKA in treating CVT. A comprehensive literature search was carried out in Medline, Embase and Cochrane Stroke Group Trials Register using a suitable keyword/MeSH term search strategy. All studies published in English comparing outcomes of patients with CVT treated with DOAC or VKA were included. In total, 6 studies (5 observational studies and 1 randomized clinical trial) comprising 412 patients (age range 16-83 years) were analyzed. DOAC was used in 151 patients, while 261 received VKA. The follow-up period was 3-11 months. The efficacy of DOACs was comparable with VKA in terms of partial or full thrombus recanalization (RR 1.02, 95% CI 0.89-1.16) and excellent functional recovery with modified Rankin scale < 2 (RR 1.02, 95% CI 0.93-1.13). Patients treated with DOAC developed lower major bleeding events when compared to VKA, although this did not reach statistical significance (RR 0.44, 95% CI 0.12-1.59). We provide preliminary evidence to support DOAC as effective and safe alternatives to VKA in CVT treatment. We await the results of upcoming randomized trials to further support our results and validate the use of DOAC.

Topics: Anticoagulants; Cerebrovascular Disorders; Factor Xa Inhibitors; Humans; Treatment Outcome; Venous Thrombosis; Vitamin K

As chronic kidney disease (CKD) is a contraindication to the use of the new anticoagulants, the vitamin K antagonists (VKA) are still valid in patients with CKD, though their use may be harmful. During overanticoagulation, some patients can develop acute kidney injury (AKI), especially those with CKD, by obstruction of the renal tubules and Bowman's spaces by erythrocytes. In addition, VKA increase atherogenesis through vitamin K deficiency, which is essential for the carboxylation of proteins that inhibit calcification of vessels. Eventually, hemodialysed patients under VKA have an increased risk of stroke, especially those over 75 years of age. Therefore anticoagulation with VKA in patients with CKD should be carefully implemented and its monitoring more frequent than in non-CKD patients.

Topics: 4-Hydroxycoumarins; Acute Kidney Injury; Anticoagulants; Atherosclerosis; Blood Coagulation Disorders; Cerebrovascular Disorders; Coumarins; Humans; Indenes; Renal Insufficiency, Chronic; Vitamin K; Warfarin

Stroke outcomes in patients with atrial fibrillation (AF) tend to be worse than those in patients without AF. The objective of this study was to evaluate whether the cost benefits of anticoagulation for stroke prevention in AF may currently be underestimated by existing economic models that do not distinguish between different stroke outcomes.. A literature review was conducted in 3 areas: (1) studies comparing stroke outcomes in AF and non-AF patients; (2) studies providing long-term cost of stroke estimates; and (3) studies modeling the cost-effectiveness of anticoagulation with a vitamin K antagonist (eg, warfarin) in AF patients.. There is considerable evidence that stroke in AF patients has a worse outcome than in patients without AF, including higher mortality, severity, and recurrence rates, and greater functional impairment and dependency. Estimates of the long-term cost of stroke of different severities were between US 24,991 dollars for a mild stroke over 5 years and US 142,251 dollars for a major ischemic stroke over a lifetime (2004 prices). The cost of a severe ischemic stroke may typically be 3-times that of mild stroke. However, cost-effectiveness models for anticoagulation in patients with AF have used average (not AF-specific) cost-of-stroke data, and most have used stroke severity distributions derived from clinical trials, which may differ from those in clinical practice.. Existing economic models underestimate the cost benefits of anticoagulation for stroke prevention because they do not adjust for poorer outcomes associated with cardioembolic strokes.

Topics: Aged; Aged, 80 and over; Anticoagulants; Atrial Fibrillation; Brain Ischemia; Cerebrovascular Disorders; Clinical Trials as Topic; Cost-Benefit Analysis; Humans; Ischemia; MEDLINE; Middle Aged; Models, Theoretical; Multivariate Analysis; Quality-Adjusted Life Years; Risk Factors; Stroke; Time Factors; Treatment Outcome; Vitamin K; Warfarin

To review the risk and pathogenesis of stroke associated with nonvalvular atrial fibrillation (AF) and the efficacies and risks of stroke prevention strategies.. About 16% of ischemic strokes are associated with AF; AF is an independent risk factor for stroke.. Review of the literature, focusing on 13 randomized trials of antithrombotic therapy.. The overall risk of stroke in AF patients averages about 5%/y, but with wide variation depending on the presence of coexistent thromboembolic risk factors. AF patients with low (about 1% per year), moderate (about 3% per year), and high (about 6% per year) stroke risks have been identified, but the generalizability of risk stratification schemes to clinical practice has not been fully assessed. AF patients with prior stroke or transient ischemic attack, even if remote, are at highest risk (about 12% per year). Adjusted-dose warfarin (target International Normalized Ratio [INR] 2-3) is highly efficacious for preventing stroke in AF patients (about 70% risk reduction) and is safe for selected patients, if carefully monitored. Aspirin has a modest effect on reducing stroke (about 20% risk reduction). The numbers of AF patients that would need to be treated with warfarin instead of aspirin for 1 year to prevent one ischemic stroke are about 200, 70, and 20 for those with low, moderate and high risk, respectively.. Many patients with nonvalvular AF have substantial rates of ischemic stroke. Stratification of stroke risk identifies AF patients who benefit most and least from lifelong anticoagulation. Warfarin is recommended for high-risk AF patients who can safely receive it. Aspirin may be indicated for those with a low stroke risk and for those who cannot receive warfarin. For AF patients considered to have a moderate risk of stroke, individual bleeding risk during anticoagulation and patient preference should particularly influence the choice of antithrombotic prophylaxis.

Topics: Aged; Aged, 80 and over; Aspirin; Atrial Fibrillation; Cerebrovascular Disorders; Clinical Trials as Topic; Female; Humans; Male; Randomized Controlled Trials as Topic; Risk Factors; Treatment Outcome; Vitamin K; Warfarin

In comparison with the incidence of cerebrovascular accident in the general population, atrial fibrillation increases the risk by a factor of five. Although age is without doubt the main risk factor for cerebrovascular accidents in patients with permanent of paroxysmal non-valvular atrial fibrillation, other independent risk factors have been identified: a previous history of hypertension, cerebrovascular accident, heart failure or diabetes. These factors enable identification of a population at risk in which oral anticoagulation may be recommended with an excellent efficacy/risk ratio. Six large scale randomised controlled multicenter trials of primary prevention have been published with a total of over 2,800 patients with non-valvular atrial fibrillation. The combined results of these trials show that treatment with vitamin K antagonist (INR 2-3) leads to a significant reduction in the risk of an ischaemic cerebrovascular accident of 64% (95% CI [51-74]; p < 0.001) and in the risk of death from all causes of 28% (95% CI [12-47]; p = 0.038) with a slight increase in the risk of cerebral haemorrhage (+ 2.7% NS). Although the benefits of aspirin therapy are not as impressive (reduction of the risk of an ischaemic cerebrovascular accident of 22%; 95% CI [0-39]; p = 0.053), this alternative may be proposed in patients under 75 years of age without the previously mentioned risk factors. The value of combined aspirin-oral anticoagulant therapy, especially in high risk patients, has not yet been established and is under evaluation.

Topics: Adult; Aged; Anticoagulants; Aspirin; Atrial Fibrillation; Cerebral Hemorrhage; Cerebrovascular Disorders; Humans; Middle Aged; Platelet Aggregation Inhibitors; Primary Prevention; Risk Factors; Treatment Outcome; Vitamin K; Warfarin

Topics: Adult; Aged; Aged, 80 and over; Aspirin; Atrial Fibrillation; Cerebrovascular Disorders; Clinical Trials as Topic; Echocardiography; Europe; Female; Fibrinolytic Agents; Humans; Male; Middle Aged; Placebos; Risk Factors; Thromboembolism; Vitamin K

Topics: Anticoagulants; Binding Sites; Blood Coagulation Factors; Blood Coagulation Tests; Cerebrovascular Disorders; Humans; Intestinal Absorption; Liver; Long-Term Care; Myocardial Infarction; Protein Binding; Recurrence; Thromboembolism; Vitamin K; Vitamin K 1

Significant reduction in bone mineral density (BMD) occurs in stroke patients on the hemiplegic and contralateral sides, correlating with the degree of paralysis and vitamin D and K deficiency due to malnutrition, and increasing the risk of hip fracture. We evaluated the efficacy of vitamin K2 (menatetrenone: menaquinone-4; MK-4) in maintaining BMD by comparing serum biochemical indices of bone metabolism between treated and untreated patients. In a random and prospective study, of 108 hemiplegic patients following stroke, 54 received 45 mg menatetrenone daily (MK-4 group, n = 54) for 12 months, and the remaining 54 (untreatment group) did not. Nine patients excluded from the study. The BMD in the second metacarpals and serum indices of bone metabolism were determined. BMD on the hemiplegic side increased by 4.3% in the MK-4 group and decreased by 4.7% in the untreated group (p < 0.0001), while BMD on the intact side decreased by 0.9% in the MK-4 group and by 2.7% in the untreated group (p < 0.0001). At baseline, patients of both groups showed vitamin D and K1 deficiencies, high serum levels of ionized calcium, pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP), and low levels of parathyroid hormones (PTH) and bone Gla proteins (BGP), indicating that immobilization-induced hypercalcemia inhibits renal synthesis of 1, 25-dihydroxyvitamin D (1, 25-[OH]2D) and compensatory PTH secretion. Both vitamins K1 and K2 increased by 97.6% and 666.9%, respectively, in the MK-4 group. Correspondingly, a significant increase in BGP and decreases in both ICTP and calcium were observed in the MK-4 group, in association with a simultaneous increase in both PTH and 1, 25-[OH]2D. One patient in the untreated group suffered from a hip fracture, compared with none in the MK-4 group. The treatment with MK-4 can increase the BMD of disused and vitamin D- and K-deficient hemiplegic bone by increasing the vitamin K concentration, and it also can decrease calcium levels through inhibition of bone resorption, resulting in an increase in 1, 25-[OH]2D concentration.

Topics: Aged; Biomarkers; Bone Density; Bone Diseases, Metabolic; Cerebrovascular Disorders; Female; Hemiplegia; Hemostatics; Humans; Male; Metacarpus; Middle Aged; Prospective Studies; Vitamin D Deficiency; Vitamin K; Vitamin K 1; Vitamin K 2; Vitamin K Deficiency

Topics: Adult; Aged; Aged, 80 and over; Aspirin; Atrial Fibrillation; Cerebrovascular Disorders; Clinical Trials as Topic; Echocardiography; Europe; Female; Fibrinolytic Agents; Humans; Male; Middle Aged; Placebos; Risk Factors; Thromboembolism; Vitamin K

Nine out of 47 (19%) patients on chronic anticoagulation with warfarin, as secondary prophylaxis after myocardial infarction, initially treated with streptokinase, had thromboembolic complications within 4 weeks after sudden (7/25) or gradual (2/22:NS) warfarin withdrawal. The biochemical effects of warfarin withdrawal were repeatedly studied in 20 of the patients during the first 14 days following drug cessation. During the first 4 days, the levels of coagulation factors VII and IX increased more rapidly than proteins C and S. Thus, a gap was created between the factors provoking and inhibiting the coagulation process. Furthermore, plasma concentrations of fibrinopeptide A (FPA) increased, reflecting activation of the coagulation system. These laboratory findings suggest that withdrawal of warfarin creates a transient hypercoagulable state, imposing a risk of thromboembolic events in patients given anticoagulant treatment as secondary prophylaxis following myocardial infarction.

Topics: Adult; Aged; Angina, Unstable; Blood Coagulation Disorders; Blood Coagulation Factors; Cerebrovascular Disorders; Drug Therapy, Combination; Female; Heparin; Humans; Male; Middle Aged; Myocardial Infarction; Peripheral Vascular Diseases; Streptokinase; Thromboembolism; Treatment Outcome; Vitamin K; Warfarin

Oral anticoagulation therapy is frequently prescribed to kidney transplant recipients (KTRs) for prevention and treatment of thrombotic events. Over the past 10 y, direct oral anticoagulants (DOACs) have shown similar efficacy with a safety profile equal or superior to that of vitamin K antagonist anticoagulants (VKAs) in the general population. However, little data are available on kidney transplantation.. We investigated the efficacy (thrombotic events) and safety (hemorrhagic and other adverse events and graft outcomes) of DOACs in a cohort of KTRs with a renal function >30 mL/min. We then compared these patients to a control group treated by VKA.. Fifty-two KTRs treated by DOACs between 2013 and 2018 at Necker Hospital were included. Patients were with a mean age of 62 ± 13 y old and a mean glomerular filtration rate of 59 ± 20 mL/min/1.73m. The major indication was atrial fibrillation (n = 31 [60%]). Apixaban was the most commonly used agent (n = 36 [69%]). No thrombotic complications were reported under DOAC until last follow-up (14.1 ± 13 mo). In comparison to 50 controls under VKA during the same period, the bleeding rate under DOAC was significantly lower (11.5 versus 22.9 per 100 patient-y, P = 0.037) with a hazard ratio of 0.39 (95% confidence interval, 0.19-0.85, P = 0.041). No significant changes in kidney function, rejection rate, or hemoglobin level were reported.. DOACs appear to be effective and safe anticoagulants in KTRs with stable renal function.

Topics: Administration, Oral; Aged; Anticoagulants; Atrial Fibrillation; Cerebrovascular Disorders; Factor Xa Inhibitors; Female; Graft Survival; Hemorrhage; Humans; Kidney Transplantation; Male; Middle Aged; Patient Safety; Pilot Projects; Retrospective Studies; Risk Assessment; Risk Factors; Thromboembolism; Treatment Outcome; Vitamin K

Gut microbiota is emerging as a novel risk factor for atherothrombosis, but the predictive role of gut-derived lipopolysaccharide (LPS) is unknown. We analyzed (1) the association between LPS and major adverse cardiovascular events (MACE) in atrial fibrillation (AF) and (2) its relationship with adherence to a Mediterranean diet (Med-diet).. This was a prospective single-center study including 912 AF patients treated with vitamin K antagonists (3716 patient-years). The primary end point was a composite of MACE. Baseline serum LPS, adherence to Med-diet (n=704), and urinary excretion of 11-dehydro-thromboxane B. In this cohort of AF patients, LPS levels were predictive of MACE and negatively affected by high adherence to Med-diet. LPS may contribute to MACE incidence in AF by increasing platelet activation.

Topics: Aged; Aged, 80 and over; Anticoagulants; Atrial Fibrillation; Bacteria; Biomarkers; Cerebrovascular Disorders; Diet, Mediterranean; Female; Gastrointestinal Microbiome; Humans; Intestines; Kaplan-Meier Estimate; Lipopolysaccharides; Male; Myocardial Ischemia; Patient Compliance; Platelet Activation; Prospective Studies; Protective Factors; Risk Factors; Rome; Time Factors; Treatment Outcome; Vitamin K

Data are limited on the safety of periprocedural anticoagulation with novel oral anticoagulants (NOACs) in patients undergoing pulmonary vein isolation (PVI) using the second-generation cryoballoon (CB) for the treatment of atrial fibrillation.. We hypothesized that the incidence of acute periprocedural complications in patients undergoing PVI do not differ between patients treated with VKA compared to NOACs.. In 200 consecutive patients (mean age, 64.3 _ 10.6 years; female, n = 83) with symptomatic atrial fibrillation, PVI using the second-generation 28-mm CB was performed. In patients treated with NOACs, the medication was stopped the day of the procedure and continued the evening after the procedure with a reduced dosage. Patients treated with phenprocoumon were continued on uninterrupted phenprocoumon with a target INR of 2 to 3. If INR was <2, bridging with low-molecular-weight heparin was performed.. Forty-seven of 200 patients (23.5%) were treated with a vitamin K antagonist (VKA) and 55 (27.5%) were treated with apixaban, 67 (33.5%) with rivaroxaban, and 31 (15.5%) with dabigatran. Seven (3.5%) major complications occurred in the overall population. Major bleeding complications did not differ significantly between the 2 groups (P = 0.23). One patient taking VKA had a pericardial tamponade at the end of the procedure; 2 patients treated with apixaban developed a groin hematoma requiring surgical intervention. Transient ischemic attack occurred in 1 patient of the apixaban and rivaroxaban group.. Apixaban, rivaroxaban, and dabigatran, compared with uninterrupted VKA, did not show a higher risk for major bleeding or ischemic complications in patients undergoing PVI using the second-generation CB.

Topics: Administration, Oral; Aged; Antithrombins; Atrial Fibrillation; Cardiac Catheters; Cerebrovascular Disorders; Cryosurgery; Dabigatran; Drug Administration Schedule; Drug Monitoring; Equipment Design; Factor Xa Inhibitors; Female; Heparin, Low-Molecular-Weight; Humans; International Normalized Ratio; Male; Middle Aged; Phenprocoumon; Postoperative Hemorrhage; Pyrazoles; Pyridones; Retrospective Studies; Risk Factors; Rivaroxaban; Time Factors; Treatment Outcome; Vitamin K

To describe a case of subtherapeutic international normalized ratio (INR) associated with concomitant use of warfarin and banana flakes in a patient with diarrhea.. A man in his 30s was hospitalized for an elective procedure, but his stay was complicated by cerebral venous thrombosis requiring intravenous infusion of unfractionated heparin, ventilator-associated pneumonia, bacteremia requiring broad-spectrum antimicrobials and percutaneous endoscopic gastrostomy tube placement, and diarrhea. Eventually, the heparin was transitioned to warfarin. After several days of therapeutic INR, the INR became subtherapeutic and remained so for 3 days. The decreased INR correlated temporally with initiation of consistent administration of dried banana flakes to treat diarrhea and the subsequent decrease in the rate and extent of diarrhea. Diarrhea decreases the amount and activity of vitamin K-producing intestinal flora and dietary vitamin K absorption, resulting in increased INR. Resolution of diarrhea secondary to banana flakes administration in this patient may have contributed to the decreased INR by causing a relative increase in vitamin K-producing flora and vitamin K absorption. A probability score of 5 was obtained upon applying the Drug Interaction Probability Scale modified to address interactions between warfarin and dietary supplements, indicating a probable interaction between warfarin and banana flakes.. Concomitant use of warfarin and banana flakes supplements may result in a reduced rate and extent of diarrhea and may be associated with subtherapeutic INR and decreased warfarin efficacy. Practitioners must be aware of this potential interaction and closely monitor INR and adjust warfarin doses accordingly.

Topics: Adult; Anticoagulants; Cerebrovascular Disorders; Diarrhea; Dietary Supplements; Drug Interactions; Humans; International Normalized Ratio; Male; Musa; Venous Thrombosis; Vitamin K; Warfarin

Patients undergoing elective electrical cardioversion (ECV) for atrial fibrillation have a temporarily increased risk of thromboembolism. Current guidelines recommend adequate anticoagulation for ≥3 consecutive weeks precardioversion, i.e. consecutive INR values 2.0-3.0 in patients with vitamin K antagonists (VKA). We aimed to evaluate the occurrence and impact of subtherapeutic INRs precardioversion and to study factors associated with these unwanted fluctuations.. We recruited 346 consecutive patients undergoing elective ECV in the Maastricht University Medical Centre between 2008 and 2013. Predictors of subtherapeutic INR values were identified and incorporated into a logistic regression model.. A subtherapeutic INR precardioversion occurred in 55.2% of patients. The only statistically significant predictor was VKA-naivety (Odds Ratio (OR) 4.78, 95% Confidence Interval (CI) 2.67-8.58, p<0.001). In patients with ≥1 subtherapeutic INR precardioversion, time from referral until cardioversion was 91.1±42.8days, compared to 41.7±26.6days (p<0.001) in patients without subtherapeutic INRs. No thromboembolic events occurred <30days after the ECV. Independent predictors for the combined endpoint of cardiovascular death, ischemic stroke and the need of blood transfusion (n=30, median follow-up of 374days) were coronary artery disease in the history (OR 3.35, 95%CI 1.54-7.25, p=0.002) and subtherapeutic INR precardioversion (OR 3.64, 95%CI 1.43-9.24, p=0.007).. The use of VKA often results in subtherapeutic INRs precardioversion and is associated with a significant delay until cardioversion, especially in patients with recent initiation of VKA therapy. Furthermore, subtherapeutic INR levels prior to ECV are associated with the combined endpoint of cardiovascular death, ischemic stroke and the need of blood transfusion.

Topics: Aged; Anticoagulants; Cerebrovascular Disorders; Cohort Studies; Electric Countershock; Female; Follow-Up Studies; Heart Diseases; Humans; International Normalized Ratio; Male; Middle Aged; Netherlands; Prospective Studies; Registries; Time Factors; Vitamin K

Antithrombotic medication plays a key role in the treatmentand secondary prophylaxis of atherothrombotic conditions. Numerous studies have found that acetylsalicylic acid is effective in reducing the incidence of (recurrent) acute vascular events, such as myocardial infarction or ischaemic stroke. For coronary atherothrombosis, anticoagulation with vitamin K antagonists was shown to be slightly superior to acetylsalicylic acid in high-risk patients. Two major trials, the 'Stroke prevention in reversible ischemia trial' (SPIRIT) and the 'European/Australasian stroke prevention in reversible ischaemia trial' (ESPRIT), showed that vitamin K antagonists were more effective than placebo in the prevention of ischaemic stroke, but the favourable effect was completely offset by a higher incidence of major bleeding (including intracerebral bleeding) in patients using vitamin K antagonists. In the ESPRIT trial, the combination of acetylsalicylic acid and dipyridamole provided a modest benefit over acetylsalicylic acid alone in the prevention of (recurrent) ischaemic stroke.

Topics: Aspirin; Cerebrovascular Disorders; Fibrinolytic Agents; Humans; Platelet Aggregation Inhibitors; Recurrence; Treatment Outcome; Vitamin K

Topics: Anticoagulants; Cerebrovascular Disorders; Dentistry; Tooth Extraction; Vitamin K

Topics: Arteriosclerosis; Atrial Fibrillation; Cerebrovascular Disorders; Coronary Disease; Dicumarol; Diet; Diet Therapy; Family Practice; General Practice; Humans; Intracranial Embolism; Intracranial Embolism and Thrombosis; Myocardial Infarction; Prothrombin Time; Thrombosis; Vitamin K; Warfarin