Development of a novel clinical platelet analyser

Funding body/stream	NIHR - Invention for Innovation (i4i)
Chief investigator	Professor Alastair Poole
Institution	University of Bristol & University Hospitals Bristol NHS Foundation Trust
Start date and duration	1^st April 2014 for 2 years
Amount	£543,926
Summary	The ability of blood to clot is critical to us to stop bleeding. There is however a wide variety of circumstances where the mechanisms underlying clot formation are abnormal or need to be controlled by drugs. People vary from those who bleed too easily through to those at risk of thrombosis, where blood clots too readily, blocking blood vessels and leading to conditions such as deep vein thrombosis or heart attack. Blood platelets are the central cell involved in this process. Although several bedside tests of how well platelets function are currently available for clinical use, none provide estimates accurate enough to predict whether a patient has a tendency to bleed or is at high risk of thrombosis. This is enormously important in a variety of hospital-based situations, including major surgery, patients on antithrombotic therapies and patients undergoing blood transfusions. We have therefore developed a new medical instrument for measuring platelet function. This instrument is readily developable into a bedside system with the potential to be transformational. The system will, when developed, take a single small blood sample and analyse platelet function within 3 minutes. Importantly our device will provide a numerical readout based upon a novel method of analysing the images of clots as they form under conditions much closer to those inside the patient's body than any instrument currently available. Our aim is to demonstrate the effectiveness of this novel tool in the clinic with a view to predicting clinical risks and to direct antiplatelet drug management on a patient-specific basis. Development will take place in 3 phases: (1) hardware refinement and miniaturisation, (2) software engineering and analytical tools development and (3) taking measurements from patients, such as those undergoing coronary artery bypass graft surgery, and comparing results with existing techniques and against clinical outcome.
Impact	A rapid, robust and reliable assay of platelet function, that provides a clear, quantifiable estimate of a patient's propensity either to bleed or to undergo vessel blockage through thrombosis, would have multiple benefits to the patient, and to the wider management of these issues by the NHS. We envisage that our system, because it measures platelet function in a more physiological manner and because of the development of novel algorithms for derivation of predictive parameters of platelet function and thrombotic potential, will have clear benefits in several clinical and patient care areas: 1. prediction of bleeding potential in patients prior to surgery. 2. prediction of post-surgical thrombotic complications 3. monitoring of response to antiplatelet agents 4. assessment of functionality of platelet packs for transfusion Although outside the remit of the present application, it is also envisaged that this technology may be developed, through further miniaturisation and use of microfluidic approaches, into home testing apparatus which could provide significant benefits for management of bleeding and thrombotic problems in the home setting. The apparatus could be developed to allow remote medical care, through connectivity to internet, and have significant impact upon patient care and upon the ability to manage patients outside of the hospital environment.
Patient and public involvement	We currently have two lay people advising the project. Our first, has previous experience in fluid mechanics and rheology as suggested by the referee of our preliminary application. Our second lay advisor is a patient on AM's list who has advised us on the wording of the lay summary and offered useful insights into a patient's view of this research. Specifically he has suggested that we consider adapting our sampling mechanism to collect blood from a finger prick instead of an intravenous blood sample. This fits very well with our plans to miniaturise the instrument and will become a stretch target of this project. The lay advisor has also asked us to consider if our device could be made suitable for home use and tele-medicine. This latter suggestion may be beyond the scope of this initial project but points to an extremely important avenue for further development. We have invited our current lay advisors to attend our biannual project management meetings and have requested funds to cover their expenses. One lay advisor, a retired academic with extensive experience on fluid mechanics, has offered his technical advice if necessary (as suggested by the referee to our preliminary proposal).