ISTH Vienna July 2008
Atrial fibrillation (AF) is a major contributor to stroke and thromboembolism. Antithrombotic therapy is beneficial, and substantial trial data supports the use of anticoagulation therapy for moderate-high risk subjects. The most recent metaanalysis by Hart et al (2007) concluded that when compared with control, adjusted-dose warfarin and antiplatelet agents reduced stroke by 64%(95% CI, 49% to 74%) and 22%(CI, 6% to 35%), respectively. Adjusted-dose warfarin was also more efficacious than antiplatelet therapy (relative risk reduction, 39% [CI, 22% to 52%]) (12 trials, 12 963 participants). The most recent comparison of warfarin versus aspirin comes from the Birmingham Atrial Fibrillation Treatment of the Aged Study (BAFTA) which showed that warfarin was more effective than aspirin for stroke prevention amongst elderly patients with AF, with no significant difference in major bleeding between warfarin and aspirin. Despite the sound evidence from clinical trials and the many published guidelines, uptake of anticoagulation treatment in patients with AF is still suboptimal. Many reasons exist – these include patient centred factors, physician centred factors and health care system related factors – and all need efforts to address the different issues raised, in order that. Many patients dislike warfarin due to the inconvenience of monitoring, as well as food and drug interactions. Physicians are not good at stroke risk stratification, nor at estimating stroke or bleeding risks. Finally, health care systems need to have a holistic approach to educating the patient and physician, as well as appropriate facilities for anticoagulation monitoring, with support for hospital-based, home-based (or self monitoring) and/or point or care systems.
Gregory YH Lip, MD FRCP[Lond, Edin, Glasg] DFM FACC FESC, Professor of Cardiovascular Medicine, University Department of Medicine, City Hospital, Birmingham B18 7QH, England UK, g.y.h.lip(at)bham.ac.uk (July, 2008)
There is controversy regarding the optimal management of anticoagulation per-operatively. The reason is the lack of randomized trials. Minor procedures may be performed without interruption of anticoagulation and the discussion is usually regarding major surgery. For the option of only stopping vitamin K antagonists (VKA) about 5 days before and restarting after surgery are 1) the arguments of very low thromboembolic risk by extrapolation to the brief unprotected period, 2) the risk of bleeding after surgery with additional bridging anticoagulation, 3) the complexity of the regimen and 4) in some countries also the cost of low-molecular-weight heparin (LMWH). There is also a possibility that post-operative bleeding requires stopping of all anticoagulants with an increase of the risk of thromboembolic complications.For the option of bridging anticoagulation, usually with LMWH or perhaps unfractionated heparin are the arguments that 1) a postoperative stroke has more serious consequences than a bleeding, and 2) that the risk of thromboembolism is unproportionally high due to the activation of coagulation.Additional questions are 1) at what time point VKAs should be stopped before surgery – 5 days before or 2 days before in combination with a small dose of vitamin K, 2) if VKA should be restarted with the usual maintenance dose or a loading dose and 3) the optimal management of antiplatelet agents.These issues will be discussed during the symposium and information about some ongoing randomized trials will be provided.
Sam Schulman, MD, Hamilton, Canada (July 2008)
Treatment with vitamin K antagonists (warfarin or coumadin derivatives) requires repeated monitoring of the intensity of anticoagulation and regular dose-adjustment. Nevertheless, many patients are not in the therapeutic target range for a considerable proportion (30-50%) of the time. In addition, the repeated laboratory checks and visits to the (anticoagulation) clinic or office are time consuming and may have a negative impact on patient satisfaction. Recently, reliable portable coagulometers have become available and these devices allow the measurement of the International Normalized Ratio (INR) from a small drop of capillary blood, thereby enabling patients to self-manage their anticoagulation. Clinical studies show that self-testing of the INR and self-adjusting of the warfarin dose results in a better control of anticoagulation in comparison with regular care by general practitioners or specialists and is at least as good as management by a specialized anticoagulation clinic. Moreover, treatment-related patient satisfaction and quality of life improves in patients performing self-management of anticoagulation.
Marcel Levi, MD PhD, Chairman, Dept. of Medicine, Academic Medical Center, University of Amsterdam, The Netherlands (July, 2008)
The target of the International Self-Monitoring Association of oral Anticoagulated Patients (ISMAAP) is to offer patients a better understanding what coagulation means.How to live with anticoagulants. What kind of risks exist and also the benefit for anticoagulated patients.On the other hand we are looking for a better cooperation between patients and physicians.Physicians should understand the problems and worries of the patients when patients have to be on longtime anticoagulation. Here we need a better way of communication.We know that the life with anticoagulants is like a journey between Scylla and Charybdis.Patients can manage that if they are actively supported by their physicians how to sail between Scylla and Charybdis.
Christian Schaefer, (ISMAAP) Geneva, Switzerland
