Health & Safety Science Abstracts

BACKGROUND: Transapical off-pump mitral valve (MV) repair is a novel minimally-invasive surgical technique, allowing to correct mitral regurgitation (MR) caused by chordae tendineae rupture. While numerical simulation of the MV structure has proven to be useful to evaluate the effects of the MV surgical repair techniques, no numerical simulation studies on the outcomes of transapical MV repair have been done up to now. OBJECTIVE: The purpose of this study is to evaluate the transapical MV repair using finite element modeling and to determine the effect of the neochordal length on the function of the prolapsing MV. METHODS: The reconstruction of the MV geometry based on the patient-specific data was performed. In order to simulate prolapse, chordae inserted into the middle segment of the posterior leaflet (P2) were ruptured. A total of four virtual transapical repairs using neochordae of different length were performed. The function of the MV before and after virtual repairs was simulated. RESULTS: The evaluation of the effect of the neochordal length on post-repair MV function showed that the length of the implanted neochordae has a significant impact on the correction of MR caused by chordae tendineae rupture. CONCLUSIONS: The presented results can improve the understanding of the effects of transapical MV repair.

In this paper a method is proposed to evaluate the heart’s coronary vessels’ status based on the elimination of large coronary branches from IR-thermal image. This method makes it possible to determine nutrient cardiac blood circulation by calculation of the rate of heat spreading in small coronary vessels in the myocardium at hypothermia and hyperthermia under the conditions of artificial blood circulation.

BACKGROUND: Upper extremity (UE) motor function deficits are commonly noted in multiple sclerosis (MS) patients and assessing it is challenging because of the lack of consensus regarding its definition. Instrumented biomechanical analysis of upper extremity movements can quantify coordination with different spatiotemporal measures and facilitate disability rating in MS patients. OBJECTIVE: To identify objective quantitative parameters for more accurate evaluation of UE disability and relate it to existing clinical scores. METHODS: Thirty-four MS patients and 24 healthy controls (CG) performed a finger-to-nose test as fast as possible and, in addition, clinical evaluation kinematic parameters of UE were measured by using inertial sensors. RESULTS: Generally, a higher disability score was associated with an increase of several temporal parameters, like slower task performance. The time taken to touch their nose was longer when the task was fulfilled with eyes closed. Time to peak angular velocity significantly changed in MS patients (EDSS > 5.0). The inter-joint coordination significantly decreases in MS patients (EDSS 3.0–5.5). Spatial parameters indicated that maximal ROM changes were in elbow flexion. CONCLUSIONS: Our findings have revealed that spatiotemporal parameters are related to the UE motor function and MS disability level. Moreover, they facilitate clinical rating by supporting clinical decisions with quantitative data.

BACKGROUND: Integration of the verticalization robot, Erigo, with functional electric stimulation and passive leg movements in the postacute rehabilitation of neurological patients could reduce the risk of secondary complications and improve functional outcomes (i.e. orthostatic hypotension, postural control and walking ability). OBJECTIVE: The aim of this study was to estimate and quantify changes in the postacute stage, mainly related to heart rate and blood pressure in functional recovery, postural parameters, walking ability and psychoemotional reactions, during training using the verticalization robot Erigo. METHODS: Six patients [three suffering from a stroke (ST) and three with spinal cord injuries (SCI)] participated in 10 sessions of physical therapy with the verticalization robot during primary inpatient rehabilitation. Functional state changes were assessed using clinical tests before and after the treatment, and the loading tolerance during Erigo training was noted. RESULTS: In early rehabilitation, Erigo training was safe and effective at improving orthostatic tolerance, posture and positive emotional reactions in both the ST and SCI patients (P < 0.05). In addition, advanced technologies were more effective at boosting the orthostatic tolerance in SCI patients, while they were more effective at increasing the dynamic balance and walking ability in ST patients (P < 0.05).

Background: Long sitting causes many health problems for people. Healthy sitting monitoring systems, like real-time pressure distribution measuring, is in high demand and many methods of posture recognition were developed. Such systems are usually expensive and hardly available for the regular user. Objective: The aim of study is to develop low cost but sensitive enough pressure sensors and posture monitoring system. Methods: New self-made pressure sensors have been developed and tested, and prototype of pressure distribution measuring system was designed. Results: Sensors measured at average noise amplitude of a = 56 mV (1.12%), average variation in sequential measurements of the same sensor s = 17 mV (0.34%). Signal variability between sensors averaged at 100 mV (2.0%). Weight to signal dependency graph was measured and hysteresis calculated. Results suggested the use of total sixteen sensors for posture monitoring system with accuracy of < 1.5% after relaxation and repeatability of around 2%. Conclusion: Results demonstrate that hand-made sensor sensitivity and repeatability are acceptable for posture monitoring, and it is possible to build low cost pressure distribution measurement system with graphical visualization without expensive equipment or complicated software.

BACKGROUND: Simulation divergence due to the backflow through the outlet boundary is a common, but not fully addressed challenge in patient-specific simulations of the aortic valve flows. OBJECTIVE: The purpose of this study is to develop the outlet boundary conditions aiming to improve convergence of the patient-specific aortic valve computations and to control the backflow in the case of partial reversal of the flow through the outlet. METHODS: Haemodynamic analysis of the aortic valve flows governed by the Navier-Stokes equations is performed by using the finite volume method. The pressure distribution, obtained from the convergent computations driven by the outflow boundary condition, is approximated by the parabolic surface of revolution and prescribed on the outlet as the novel pressure boundary condition. RESULTS: Various types of outlet boundary conditions are investigated to evaluate their influence on the resulting backflows. The outflow boundary condition produces a smaller backflow than other investigated boundary conditions, but it causes the solution divergence. The proposed outlet boundary condition allows for continuing the solution and preserving the expected backflow. CONCLUSIONS: The proposed outlet boundary condition helps to achieve a convergent solution and to conserve the observed backflow by varying the convexity of the specified pressure surface.