What we see now are government systems starting to put greater emphasis on thrombosis prevention and, as a result of that, the benefits of what we know will be applied to greater numbers of patients.

Now, with regards to what we know currently, the era of low-molecular-weight heparin. The past 20 years of clinical research and clinical practice have provided us tremendous insights, both in recognizing which patients are at risk of thrombosis and therefore would benefit from thromboprophylaxis and also provided us with certainty that the low-molecular-weight heparins can be used safely and effectively in broad ranges of patient populations to prevent DVT [deep vein thrombosis] and pulmonary embolism.

Now, coming down the line are some exciting studies, particularly in 2 populations of patients where thrombosis is common and where all the benefits of thromboprophylaxis have still not been realized. The first of these are the acutely ill medical patients admitted to hospital. These patients are at high risk for developing thrombosis and certainly the current standard is to provide them with thromboprophylaxis in hospital with either the low-molecular-weight heparins, agents such as enoxaparin, or unfractionated heparin. What’s not clear is how long one should provide low-molecular-weight heparin or unfractionated heparin to these patients.

Within the acutely ill medical population there is a specific group of patients — those who have experienced acute ischemic stroke — who are at very high risk for the development of venous thromboembolic complications in the days and weeks after their stroke. Here again, there is the opportunity to provide thromboprophylaxis either with low-dose unfractionated heparin or with low-molecular-weight heparins. But a trial which is currently ongoing is evaluating a comparison of low-dose unfractionated heparin against the low-molecular-weight heparin enoxaparin and this is the PREVAIL [Prevention of VTE After Acute Ischemic Stroke With LMWH Enoxaparin] Study.

I think this study will be particularly important because one of the questions that concerns clinicians when providing thromboprophylaxis to patients who have had a stroke is how safe my thromboprophylaxis strategy is, in terms of any potential bleeding risk. And the provision of low-molecular-weight heparin has the theoretical advantage of not only having the same efficacy, but also potentially offering some safety advantage in this high-risk population. And the results of this study, the PREVAIL Study, are keenly awaited and should be available towards the end of this year.

A second broad group of patients where the benefits of thromboprophylaxis have yet to be fully explored, are patients with malignant disease. Now we know from excellent studies — the ENOXACAN [Enoxaparin and Cancer] I and in particular the ENOXACAN II Study — that low-molecular-weight heparin provided perioperatively and for up to 1 month after operation, in patients who have undergone a laparotomy for cancer, is associated with reduction in the frequency of deep vein thrombosis.

And, the purpose in doing this is to try and understand how venous thromboembolic disease affects the natural history of common cancers. At what stage in the natural history of malignant disease thrombosis occurs, how is it currently managed, what are the implications of the management in terms of bleeding and other adverse complications associated with anticoagulant therapy, and to determine how the thrombosis actually affects the overall outcomes for the patient and the cancer.

These data are only sparingly available in the current literature and I think it’s very important for us to try and understand how thrombosis actually affects and complicates cancer so that we can then design appropriate trials for the vast number of ambulant cancer patients receiving their chemo- or radio-therapy out of hospital, who remain a thrombosis risk and where we have not currently got sufficient data to provide guidance to our clinical colleagues on how and when antithrombotic prophylaxis should be provided.

It also provides the opportunity, therefore, to know the baseline risk in the various cancer populations and design appropriate clinical trials in those specific populations and, therefore, expose those in a clinical trial to have the greatest potential benefit if the interventions were shown to be successful.

Now I think it’s particularly pertinent because if you think about acutely ill medical patients, the factors that drive their risk of thrombosis in hospital are often the factors that drive the risk of thrombosis out of hospital. The underlying condition they have, the general state of health, isn’t markedly different in hospital as it is when they are immediately discharged from hospital. And therefore, one might suppose that their ongoing risk for thrombosis is also great even after hospital discharge. This question hasn’t been tested before, but the EXCLAIM Study, with nearly 8000 patients, certainly has the power in statistical terms and has the methodological soundness with a screening for all thrombosis events at a fixed time point, to potentially answer this question.

And certainly in other high-risk populations, those, for instance, who have undergone hip-replacement operations, extended prophylaxis has now been shown to be beneficial. We have discussed earlier the question of extended prophylaxis in cancer surgical patients and clearly the other risk population where this question needs to be answered are these acutely ill medical patients.

I think the great confidence we have with low-molecular-weight heparins is 20 years of experience and a huge amount of information both from well-conducted clinical trials and from real-life experience that tells us the low-molecular-weight heparins are effective and safe in a broad range of populations.

What the data from these new studies will do, is tell us when we need to give the low-molecular-weight heparins for an extended period and to tell us whether giving it for a longer time is as safe as it is giving it for the short time, because certainly we know in hospital, low-molecular-weight heparin prophylaxis is very safe.

So I think they have really the opportunity to have a tremendous impact and benefit large numbers of patients, but clearly we need the data from these prospective trials to confirm which populations are going to benefit and what the degree of benefit will be and how long the low-molecular-weight heparin should be extended for.

Thank you very much for inviting me. I greatly enjoyed it.