Simulations of the Cardiovascular System Using the Cardiovascular Simulation Toolbox

In the present document, six mathematical models of the cardiovascular system are studied and implemented in MATLAB R2013a using an updated version of the Cardiovascular Simulation Toolbox proposed by O. Barnea at the Tel-Aviv University. All the mathematical models are based on electrical lumped-parameter analogies. The results of the simulations are compared with a list of expected hemodynamic parameters and contrasted with laboratory values

A novel approach for treating resistant hypertension using a controlled-pump accumulator relief device

Hypertension contributes to cardiovascular morbidity and mortality worldwide. While many hypertensive patients respond to drug therapy, a growing number of these cases are called resistant hypertension (RH), when patients cannot control their blood pressure to goal levels despite the use of multiple antihypertensive medications. While current interventional treatments for RH are based on dealing with the nervous system, there is no existing procedure that considers altering the way in which blood is pumped into the aorta such that to reduce blood pressure. We hypothesize that RH may be controlled by altering the way in which blood is pumped into the aorta. We introduce a novel idea of implementing what we called the accumulator device, which may be classified as a mechanical assist device for the cardiac system. A lumped-parameter model describing the cardiovascular system is presented and validated. The novel idea of accumulator device is also modeled and incorporated with the cardiovascular system model using analogies between the circulatory system, hydraulic systems, and electric circuits. The simulation work of the proposed accumulator device idea reveals promising preliminary results. It shows an ability to significantly decrease the systolic pressure by regulating the way in which blood is pumped into the aorta during the cardiac cycle, without reducing the cardiac output. It is our hope that this novel approach provides a transformational alternative to existing methods for treating RH, becomes a successful treatment option in the future, and improves life for millions of RH patients.Includes bibliographical reference

Assessing mechanical properties of the cardiovascular system

The elasticity of wall of the arteries plays a significant role in cardiovascular system. Capacitance of the aorta is predicative of cardiovascular events[1]. To get better understanding the function of the cardiovascular system, special attention should be paid to digest the traditional two-element Windkessel model. Because the Windkessel model provides information of cardiovascular function and which may be useful for prevention and diagnosis of hypertension. Our research presents a series of in vitro experimental studies of compliance, peripheral resistance, and pulse waves. In this thesis, several studies have been achieved: 1) a mathematical model for the capacitance of the aorta is derived based upon the conservation of mass, and a specialized test device provided by BDC Laboratories is used to simulate the aorta by employing an arched silicone-rubber tube with a known capacitance. 2) applied and compared arterial compliance determined from blood pressure, arterial compliance determined from PWV, and mechanical capacitance in flexible tubes and animal calf aortae. 3) investigated using sensitivity analysis as the analytical technique to determine parameters which. 4) develop a new technique which based on blood pressure diagram of flexible tubes and animal aortas. In the first study corresponding to chapter five, that the entire blood-pressure state may be plotted on a single blood-pressure diagram using three nondimensional groups. This diagram illustrates the impact of altering the capacitance and ejection period on the pulse pressure that exists within the aorta. In the second study corresponding to chapter six, the sensitivity analysis that has been used to figure out sensitivity coefficients with the largest magnitude is based on the most sensitive parameter that can be adjusted if we want to alter a pressure. In the third study corresponding to chapter seven, arterial compliance determined from blood pressure is more straightforward approach than arterial compliance determined from PWV to measuring the arterial stiffness. By that allowing hypertension to be managed. In the last study corresponding to chapter seven, it is figured out that total cardiovascular capacitance plays a significant role in determining the risk factors for cardiovascular disease, and the systolic and diastolic pressures during the cardiac cycle. In addition to cardiovascular capacitance other parameters that contribute to creating blood pressure include total peripheral resistance, stroke volume, ejection period, and heartrate. In conclusion, this research, combined with additional support may permit the realization for measuring arterial stiffness in the home setting. This research may make significant paradigm changes in prognosis and diagnosis of arterial stiffness and other cardiovascular events.Includes bibliographical references (pages 188-194)