Putting a stop to leg clots Deep vein thrombosis is a major concern for health authorities, and a lot of attention is focused on prevention in patients at risk of developing blood clots in the leg. Intermittent pneumatic compression (IPC) therapy could offer an effective, cost-efficient method of prevention, a topic at the heart of Doctor Paul Ackermann’s research. Many
patients have their legs immobilized after surgery, which affects blood circulation and increases the risk of a blood clot in the limb, known as venous thromboembolism or deep vein thrombosis (DVT). While low molecular weight heparins are available to minimize the risk of DVT, they are not always effective in patients whose lower limbs have been immobilized. “Low molecular weight heparins are often given as a subcutaneous injection in the stomach, then distributed throughout the body via the blood circulation. However, when the blood circulation in the lower limbs is limited, for example during immobilization, patients don’t receive the optimal prophylactic effect from the treatment” explains Doctor Paul Ackermann, a Lecturer and Senior Physician at the Karolinska Institute and Karolinska University Hospital, Stockholm. Preventing leg blood clots is a major health priority; Dr Ackermann and his colleagues are now assessing the effectiveness of an alternative approach called intermittent pneumatic compression (IPC) therapy, based on a device
Mechanisms of action of IPC applied to the calf. Increased venous return Increased arterial circulation Improved oedema reduction Increased chemical bloodcloth prophylaxis
has to be persistent in using the treatment during that time. This is one of the main challenges in this study, to get the patients to use the device consistently” says Dr Ackermann. Beyond preventing blood clots in people recovering after surgery or injury, this treatment could also be used to improve health; “The treatment could be beneficial for people who live a sedentary lifestyle which includes prolonged sitting. It’s logical to think that these individuals might have low blood
The IPC treatment could be beneficial for people who live a sedentary lifestyle which includes prolonged sitting. It’s logical to think that these individuals might have low blood circulation in their limbs. which squeezes the calf muscles to increase the blood flow. “IPC is a mechanical therapy designed to address the blood stasis problem, when blood flow in the limb is low, such as during leg immobilization” he outlines. This treatment is commonly used today in hospitals immediately after surgery in patients who are at high risk of forming blood clots in the leg. Dr Ackermann aims to study its effectiveness as a home-based therapy in a group of 1,400 patients in a clinical, randomized trial of orthopaedic patients with lower limb injuries requiring leg immobilization. The IPC treatment, which is performed when the patient is in a sedentary position - i.e. sitting or lying down - has to be continued during the whole time that a patient’s leg is immobilized, which could be up to 8 weeks in some cases. “The patient
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circulation in their limbs, and that more profound circulation would be beneficial” Dr Ackermann points out. “The treatment could also be used for other patient groups. We have in this study chosen to investigate patients which we know are at high risk of developing a blood clot.” The cost-efficiency of the IPC approach is another important consideration in Dr Ackermann’s research. With budgets under strain, health authorities are keen to use resources efficiently, a context in which the IPC treatment takes on clear importance. “Patients borrow the machine which produces the intermittent compression. It is very costefficient in comparison to pharmacological prophylaxis,” explains Dr Ackermann. Researchers are currently studying the effectiveness of the treatment on a large
cohort of patients, which will provide the foundations for a more detailed cost-efficiency analysis in future. “We’ve looked at around 100-150 patients so far in this study, and we’re planning to include around 1,400 patients overall,” continues Dr Ackermann. “We are looking to heighten awareness among people. When people are more aware of the problem of blood clots in the leg, we can start to include more patients to assist with this very big and important project.”
StopLegClots Swedish multicenter Trial of Outpatient Prevention of Leg Clots The study is funded by the Swedish Research Council nr: 2017-00202. Supported by the Swedish Orthopedic Traumatology Society (SOTS). Associate Professor Paul Ackermann M.D, Ph.D. Specialist in Orthopaedic Surgery Orthopaedic Department Karolinska University Hospital SE-17176 Stockholm SWEDEN T: +46 8 517 700 00 E: paul.ackermann@ki.se W: https://ki.se/mmk/stopleg-clots Dr. P.W. Ackermann is the Head of the Integrative Orthopedic Research Group, focusing his research on neuro-vascular regulation of venous thromboembolism, pain and musculoskeletal tissue repair in collaboration with a global network of researchers.
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