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Problem: Cardiovascular diseases are still the most common cause of death in developed industrialised countries. Heart transplantation is the last possible form of therapy for many patients in the final stage. Mechanical cardiovascular assist devices (VADs) are used to bridge the waiting time for a donor heart or as a cardiac replacement. A serious complication is thrombosis. Due to the high stress loads in the pump flow and contact with an artificial surface, platelets are activated which attach themselves to the foreign surfaces of the cardiac support system and locally lead to the activation and attachment of further platelets. If these thrombi become detached, they can lead to the closure of blood vessels in the bloodstream, leading to heart attacks and strokes. The administration of anticoagulants reduces thrombosis, which leads to an increased bleeding tendency of the patient. Despite previous efforts to minimize the thrombogenicity of the surfaces, the rate of thromboembolic complications is still very high at 27% per patient year.
The aim of the project is to avoid thrombo-embolic complications. This is to be achieved by developing, testing and applying a novel coating for blood-bearing elements of cardiac support systems. The coating is intended to prevent the formation of thrombi and thus enable a breakthrough in the use of cardiac support systems.
The coating is based on a substance that does not interact with platelets. The components coated with the substance are thus not recognized as foreign material. The substance is a polyglycerin developed by the cooperation partner of Freie Universität Berlin.
The effect of the novel polyglycerin coating differs from that of heparin, which is used in previous antithrombogenic coatings. While heparin intervenes relatively late in the complicated process of blood coagulation, the polyglycerin coating prevents the first step of thrombosis: the initial attachment of platelets to the surface.
The benefit of an effective, long-term stable coating results from the expected reduction of thrombo-embolic complications such as strokes and pump thrombosis. As a result, anticoagulation management of VAD patients with blood-thinning drugs can be reduced, reducing bleeding complications. This significantly increases the life expectancy and quality of life for these patients.