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Introduction: 'Safety indicators' in the anticoagulant management of atrial fibrillation (AF) are listed in the UK NHS Improvement Document, 'Anticoagulation for AF', aiming to promote quality services. Acceptable clinical event rates are not quantified in the document., Objective: To provide clinical evaluation of the relevant safety indicators using data from a recent large European Action on Anticoagulation (EAA) study., Results: 469 clinical events were recorded in 5839 outpatients in the EAA study. The safety indicators listed in the NHS Improvement Document were related to these patients with AF. The relevance of the 'safety indicators' is confirmed by the EAA study for patients starting oral anticoagulation and for those already receiving oral anticoagulation, and quantified., Conclusion: The EAA clinical study provides a quantitative basis for the safety indicators' in AF listed in the NHS Commissioning Support Document and emphasises the importance of the document.

The risk of endoscopy in patients on antithrombotics depends on the risks of procedural haemorrhage vs. thrombosis due to discontinuation of therapy. P2Y12 receptor antagonists (clopidogrel, prasugrel, ticagrelor): For low-risk endoscopic procedures we recommend continuing P2Y12 receptor antagonists as single or dual antiplatelet therapy (low quality evidence, strong recommendation);For high-risk endoscopic procedures in patients at low thrombotic risk, we recommend discontinuing P2Y12 receptor antagonists five days before the procedure (moderate quality evidence, strong recommendation). In patients on dual antiplatelet therapy, we suggest continuing aspirin (low quality evidence, weak recommendation).For high-risk endoscopic procedures in patients at high thrombotic risk, we recommend continuing aspirin and liaising with a cardiologist about the risk/benefit of discontinuation of P2Y12 receptor antagonists (high quality evidence, strong recommendation). Warfarin: The advice for warfarin is fundamentally unchanged from BSG 2008 guidance. Direct Oral Anticoagulants (DOAC): For low-risk endoscopic procedures we suggest omitting the morning dose of DOAC on the day of the procedure (very low quality evidence, weak recommendation). For high-risk endoscopic procedures, we recommend that the last dose of DOAC be taken ≥ 48 hours before the procedure (very low quality evidence, strong recommendation). For patients on dabigatran with CrCl (or estimated glomerular filtration rate, eGFR) of 30 - 50 mL/min we recommend that the last dose of DOAC be taken 72 hours before the procedure (very low quality evidence, strong recommendation). In any patient with rapidly deteriorating renal function a haematologist should be consulted (low quality evidence, strong recommendation). [ABSTRACT FROM AUTHOR]

In an open non-randomized study, 10 patients with major bleeding and an Internationalized Normal Ratio (INR) greater than 14 were treated with 5 mg of intravenous vitamin K and 30 iu/kg of a single concentrate containing factors II, VII, IX and X (Beriplex P/N; Aventis Behring). The levels of these factors before and immediately after treatment were 4·7, 1·6, 8·5 and 1·1 iu/dl and 94, 30, 66 and 91 iu/dl respectively. The median INR before treatment was greater than 20 and, after treatment, 1·1. All patients had a satisfactory clinical response with immediate cessation of bleeding, and no thromboembolic complications occurred. [ABSTRACT FROM AUTHOR]

The role of oral Vitamin K administration in the reversal of anticoagulation is not yet clear because of a paucity of data on the early effects of treatment, apparent differences in efficacy between preparations and a lack of data comparing oral with intravenous administration. We have compared the effects on the International Normalized Ratio (INR) and activities of the Vitamin K-dependent clotting factors II, VII, IX and X at 4 h and 24 h after administration of three oral Vitamin K preparations and of intravenous Vitamin K in 64 anticoagulated patients who required non-urgent partial correction of anticoagulation. Our data confirm that correction of anticoagulation is more rapid after intravenous administration of Vitamin K than after oral administration of similar or larger doses. At 24 h, satisfactory correction of INR can be achieved using low-dose Vitamin K given by either the intravenous or oral route. Our data, and that from previous studies, suggest that there may be differences in efficacy between orally administered products. Administration of Vitamin K by either route was accompanied by changes in the activities of the Vitamin K-dependent clotting factors that reflected their respective biological half-lives. In the 24 h after treatment, the relationship between the INR and the individual Vitamin K-dependent clotting factors was similar to that described previously in stable anticoagulated patients. We conclude that the reversal of anticoagulation with warfarin is achieved more rapidly by intravenous administration of Vitamin K. Satisfactory, but slower, reversal of anticoagulation can be effected using oral Vitamin K, but there may be differences in efficacy between the products tested in our study. [ABSTRACT FROM AUTHOR]

Thrombosis is a well-recognized complication following insertion of central venous catheters and is associated with significant morbidity. In an attempt to reduce line-associated thrombosis, 108 consecutive patients with haematological malignancies were commenced on prophylactic ‘minidose’ warfarin, 1 mg/d, at the time of line insertion. This group of patients were compared with a historic group of 115 consecutive patients who had not received warfarin. Clinically-suspected venous thrombosis was confirmed by Doppler ultrasound or venography. Patients taking prophylactic warfarin had their prothrombin time measured three times per week with the aim of maintaining an INR < 1.6. Five (5%) of the 108 patients who received minidose warfarin developed a thrombosis, at a median of 72 d (range 5–166) from the time of catheter insertion. In the 115 patients who were not anticoagulated 15 (13%) developed a catheter-associated thrombosis at a median of 16 d (range 1–35). There was a significant reduction in line-associated thrombosis in patients receiving warfarin (P = 0.03). These data suggest that minidose warfarin reduces the incidence of central venous catheter related thrombosis in patients with haematological malignancies. [ABSTRACT FROM AUTHOR]

Three cohorts of patients with the factor V Leiden mutation were recruited independently (heterozygotes, homozygotes and combined thrombophilia). The antithrombotic efficacy of oral anticoagulation and the predictive value for recurrence of an idiopathic as opposed to a precipitated first event were determined. Idiopathic first events occurred at an older age than precipitated events (43 v 26 years, LR = 23.31, P < 0.001). None of the patients had a recurrent event while on warfarin but the median time to recurrence after stopping warfarin was 9 years (95%CI 0.7–17.3 years). The time to recurrence was shorter when the first event was idiopathic as opposed to precipitated (3.5 v 13 years, LR = 4.76, P = 0.029). A calculation of benefit to risk of oral anticoagulation with a target INR of 2.5 does not support the use of long-term therapy in all patients with the factor V Leiden mutation following a first thrombotic event. [ABSTRACT FROM AUTHOR]

A cohort of patients with an INR >7.0 were identified prospectively and compared with a group of patients with stable anticoagulant control. During the study 15 100 INR measurements were recorded and 31 (0.2%) were >7.0. Odds ratios of patient characteristics were calculated as an estimate of relative risk for the development of a high INR. The highest risk factor was a target INR of 3.5 (OR 7.3, 95% CI 2.6–20.2). The second highest risk factor was antibiotic therapy in the 4 weeks preceding the high INR (OR 6.2, 95% CI 1.4–27.7). Bleeding was reported more frequently in the high INR group (OR 5.4, 95% CI 2.1–13.9). Five major bleeds occurred in this group compared to none in the stable group. This analysis identifies risk factors for over-anticoagulation and hence when to intensify monitoring and when to consider pre-emptive warfarin dose reductions. [ABSTRACT FROM AUTHOR]