NUMERICAL STUDY OF HEMODYNAMICS OF LUMPED-PARAMETER MODEL FOR LOWER LIMB AMPUTEE

Although lower limb amputation has been identified as a possible risk factor of cardiovascular disease, the underlying biomedical mechanisms are not completely understood. The purpose of this study was to examine the cardiovascular hemodynamic status of lower limb amputees at different postoperative periods and life status to evaluate the impact of abnormal hemodynamics on cardiovascular system. In this paper, a centralized parameter model of the cardiovascular system with lower limb arteries was established to simulate three common conditions of amputation patients, i.e., postoperation, postoperation residual limb atrophy and postoperation both limb atrophy. The diameter of lower limb artery measured by ultrasound in 7 patients with lower limb amputation was used as the reference for parameter setting of the model. By comparing the blood pressure and blood flow waveform of the normal person model and the lower limb amputation model, we found that the amplitude of the systolic and diastolic blood pressure increased after amputation, and the peak value of the arterial flow in the abdominal aorta and below decreased significantly. In postoperation residual limb atrophy and postoperation both limb atrophy, the peak blood pressure in the central aorta increased during diastole. Such abnormal hemodynamic changes may be a risk factor of cardiovascular diseases such as hypertension and ventricular hypertrophy in lower limb amputees. The centralized parameter model established in this paper provides the change rule of hemodynamics after amputation, which can provide theoretical guidance of rehabilitation treatment and cardiovascular disease prevention of amputation patients in the future.