No abstract

Good right ventricular function is one of the major determinants of long-term outcomes in patients with implanted left ventricular assist devices (LVADs). In the present study, a computer model was developed to assess the impact of mitral regurgitation on right ventricular workload at different levels of LVAD support. Left ventricular assist device was simulated by a model of HeartMate II. The computer model has shown that the regurgitant volume of the mitral valve falls significantly only after the systolic pressure in the left ventricle decreases, which occurs at higher LVAD revolutions per minute (RPM) when there is no ejection through the aortic valve. However, at low LVAD RPM, the pressures in the left atrium and the pulmonary artery decrease significantly, despite a small decrease in regurgitant volume. According to the computer model, LVAD support decreases mitral regurgitation. Furthermore, regurgitant volume has a smaller impact on the right ventricular afterload when compared with a heart without LVAD support.

A topological groupoid G is K-pointed, if it is equipped with a homomorphism from a topological group K to G . We describe the homotopy groups of such K-pointed topological groupoids and relate these groups to the ordinary homotopy groups in terms of a long exact sequence. As an application, we give an obstruction to presentability of proper regular Lie groupoids.

The study confirmed that the TTFM measured at the proximal end of the coronary bypass could be viewed as a sum of graft capacitive flow and the flow that passes through the distal anastomosis. Graft capacitive flow increases the systolic and decreases the diastolic TTFM when measured at the proximal end of the graft. It explains the higher DF when the TTFM is measured at the distal end of the graft and the increase in the PI at the proximal end when Q decreases. As the influence of graft capacitive flow on the PI in low Q can be eliminated by performing the TTFM at the distal end of the graft, we believe that the value of PI is clinically irrelevant.

Background and Aim of the Study: The aim of this study was to use coronary computed tomography in patients with normal tricuspid aortic valves to perform detailed aortic root and aortic valve geometric analysis with a focus on the asymmetry of the three leaflets.Methods: Retrospective analysis of anonymized coronary computed tomography angiograms was performed using dedicated software, where manual aortic root segmentation and marking of several points of interest were followed by automated measurements of aortic root and leaflets. Asymmetry of the three leaflets in individual patients was assessed by calculating absolute and relative differences between the largest and the smallest of the three leaflets.Results: We analyzed 70 aortic valves, the mean patient age was 53 ± 11 years, and 50% (n = 35) of patients were female. All aortic valves were tricuspid, without calcifications and aortic roots were of normal dimensions. Some degree of asymmetry was present in all analyzed valves. Absolute and relative differences for free margin length were 3.2 ± 1.4 mm and 9.3 ± 3.8%, respectively. The largest relative difference was noted in the coaptation area (36.5 ± 16.5%) and the smallest in leaflet effective height (6.1 ± 4.8%). Using predefined cutoff criteria for absolute differences in leaflet dimensions, 86% of the valves were classified as asymmetric.Conclusions: Most normal tricuspid aortic valves show some degree of asymmetry.Equal free margin length of the three leaflets is not needed for normal tricuspid aortic valve function. Leaflet effective height showed the least amount of asymmetry confirming its importance in keeping the aortic valve competent.