Volume 30, Issue 5

This work is the numerical study of the age-dependent responses of the vascular system under low-mass high-speed impact scenario. The grid-characteristic method on the adaptive mesh model of the human thorax is the numerical tool of the study. Due to the lack of valid vascular injury criteria, the numerical model only provides information on injury risk. The numerical simulation demonstrates that an older age changes significantly the vascular response and increases the risk of aorta injury. We focused on the aorta because its rupture is the general consequence of vehicle accidents (great mass impacts at relatively low velocity). Our numerical results are in good agreement with previous studies of great-mass low-speed blunt thorax impact.

Atherosclerotic diseases of coronary vessels are the main reasons of myocardial ischemia. The value of the fractional flow reserve (FFR) factor is the golden standard for making decision on coronary network surgical treatment. The FFR measurements require expensive endovascular diagnostics. We propose a noninvasive method of the virtual FFR assessment in patient-specific coronary network based on angiography and computer tomography data. Also we analyze sensitivity of the model to the heart stroke volume.

The hydrodynamic properties of the blood flow in cerebral vessels with multiple aneurysms are studied in the paper. We compare the sets of parameters derived from the dissipation energy appearing due to the blood viscosity and computed for different aneurysms of one patient. Numerical simulations show that in most cases the dissipation energy and its derived parameters are lower in the case of ruptured aneurysm. Moreover, the average dissipation energy per unit volume is lower in all cases studied here.

A continual multicomponent model of growth of a low-invasive tumor is a developed subject to the angiogenesis and single bevacizumab therapy. The model takes into account the differences in permeabilities of the pre-existent vasculature and the vasculature formed as the result of angiogenesis. The dependence of the antitumor therapy efficacy on the bev dosage is studied. It is found out that in the case of successful treatment the tumor may pass from a compact convective growth to diffuse intergrowth followed by significant reduction in the growth rate and the number of active tumor cells. It is shown that the bev dosage sufficient for successful treatment is significantly less than it is commonly accepted in clinical practice. A scheme of bev prescription allowing a significant reduction of both the costs of therapy and its negative effects while maintaining antitumor efficacy is proposed.

In our study we developed a computational algorithm for finding optimal dosages of antiretroviral drug administration for the stabilization of HIV load at low levels. The novelty is that the pharmacokinetics and pharmacodynamics of the antiretroviral drugs were taken into account. A standard closed-loop control of HIV dynamics was constructed that stabilizes the viral load and the optimal drug administration mode was formulated. We analyze the appropriateness of the ‘drug efficacy’ based control and its relationship to a realistic drug dosage and kinetic models in the human body. The translation of the efficacy function into drug concentration is implemented via the pharmacodynamics model of the drug effect. Optimal approximation of the idealized concentration functions is based on the orthogonal projection on linear subspace of drug pharmacokinetics functions.