Analysis and design of a thrombectomy device by using simulation techniques

Purpose: In this work, we present the analysis, design and optimization of one experimental device recently developed in the UK, called the 'GP' Thrombus Aspiration Device (GPTAD). This device has been designed to remove blood clots without the need to make contact with the clot itself thereby potentially reducing the risk of problems such as downstream embolisation. Method: To obtain the minimum pressure necessary to extract the clot and to optimize the device, we have simulated the performance of the GPTAD analysing the resistances, compliances and inertances effects. We model a range of diameters for the GPTAD considering different forces of adhesion of the blood clot to the artery wall, and different lengths of blood clot. In each case we determine the optimum pressure required to extract the blood clot from the artery using the GPTAD, which is attached at its proximal end to a suction pump. Result: We then compare the results of our mathematical modelling to measurements made in laboratory using plastic tube models of arteries of comparable diameter. We use abattoir porcine blood clots that are extracted using the GPTAD. The suction pressures required for such clot extraction in the plastic tube models compare favourably with those predicted by the mathematical modelling. Discussion & Conclusion: We conclude therefore that the mathematical modelling is a useful technique in predicting the performance of the GPTAD and may potentially be used in optimising the design of the device

Modelling and simulation of a thrombectomy probe applied to the middle cerebral artery by using the bond graph technique

Thrombosis is produced by the formation of a clot inside blood vessels causing an abrupt interruption of the blood flow. In the cerebral arteries, this occlusion can take place due to the presence of a clot that has formed at another location of greater diameter. It then obstructs the cerebral artery due to its smaller cross section. The process concerning the removal of this obstruction involves catheterisation. The experimental probe under study in this paper was developed by Dr G. Pearce and Reverend Neil Perkinson [1]. The probe, which when developed further may form the basis of a new Thrombectomy Aspiration Device (TAD) is called the GPTAD. Once fully developed, the GPTAD may provide a means of clot removal from vessels in the human arterial system e.g. the cerebral vessels. The modelling that we present in this paper, taking into account the catheter, the probe, artery, blood clot and adhesion forces, may assist with the optimisation of the design of the GPTAD probe . In the model used for the simulation both mechanical and hydraulic aspects have been considered with the purpose of combining the effect of the fluid-blood transmission for the different sections of the vein and the cathete

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According to the World Health Organization, 15 million people suffer stroke worldwide each year, of these, 5 million die and 5 million are permanently disabled. Stroke is therefore a major cause of mortality world-wide. The majority of strokes are caused by a blood clot that occludes an artery in the brain, and although thrombolytic agents such as Alteplase are used to dissolve clots that arise in the arteries of the brain, there are limitations on the use of these thrombolytic agents. However over the past decade, other methods of treatment have been developed which include Thrombectomy Devices e.g. the 'GP' Thrombus Aspiration Device ('GP' TAD). Such devices may be used as an alternative to thrombolytics or in conjunction with them to extract blood clots in arteries such as the middle cerebral artery of the midbrain brain, and the posterior inferior cerebellar artery (PICA) of the posterior aspect of the brain. In this paper, we mathematically model the removal of blood clots using the 'GP' TAD from selected arteries of the brain where blood clots may arise taking into account factors such as the resistances, compliances and inertances effects. Such mathematical modelling may have potential uses in predicting the pressures necessary to extract blood clots of given lengths, and masses from arteries in the Circle of Willis - posterior circulation of the brai