BACKGROUND For blood purification systems using a semipermeable membrane, the convective mass transfer by ultrafiltration plays an important role in toxin removal. The increase in the ultrafiltration rate can improve the toxin removal efficiency of the device, ultimately reducing treatment time and cost. In this study, we assessed the effects of pulsatile flow on the efficiency of the convectiv...

Total left ventricular external power and aortic input impedance spectra were calculated from recordings of pulsatile pressure and flow in the ascending aorta of 22 human subjects undergoing cardiac catheterization. Eleven subjects had increased aortic pressure (systolic 153 + 3.8[SEM] mm Hg, p < .001; diastolic 91 + 2.4 mm Hg, p < .03; mean 118 ± 2.4 mm Hg, p < .001) and constituted the group ...

OBJECTIVE To determine the role of patched receptor (Ptc)-1 in mediating pulsatile flow-induced changes in vascular smooth muscle cell growth and vascular remodeling. APPROACH AND RESULTS In vitro, human coronary arterial smooth muscle cells were exposed to normal or pathological low pulsatile flow conditions for 24 hours using a perfused transcapillary flow system. Low pulsatile flow increas...

BACKGROUND Left ventricular assist devices (LVADs) are now widely accepted as an option for patients with advanced heart failure. First-generation devices were pulsatile, but they had poor longevity and durability. Newer generation devices are nonpulsatile and more durable, but remain associated with an increased risk of stroke and hypertension. Moreover, little is understood about the physiolo...

BACKGROUND Tissue engineering is a new approach, whereby techniques are being developed to transplant autologous cells onto biodegradable scaffolds to ultimately form new functional tissue in vitro and in vivo. Our laboratory has focused on the tissue engineering of heart valves, and we have fabricated a trileaflet heart valve scaffold from a biodegradable polymer, a polyhydroxyalkanoate. In th...

Numerical predictions of blood flow patterns and hemodynamic stresses in Abdominal Aortic Aneurysms (AAAs) are performed in a two-aneurysm, axisymmetric, rigid wall model using the spectral element method. Physiologically realistic aortic blood flow is simulated under pulsatile conditions for the range of time-averaged Reynolds numbers 50< or =Re(m)< or =300, corresponding to a range of peak Re...

The effect of non-Newtonian viscosity of blood on the steady and pulsatile flow in a straight rabbit femoral artery with various degrees of stenosis is investigated numerically using a finite element technique for the peak Reynolds numbers of 65 and 100. The Cross model is used to take into account the non-Newtonian viscosity of blood at various shear rates. The infiniteand zeroshear-rate visco...

The effect of pulsatile flow during cardiopulmonary bypass on the hormonal stress response was studied in 26 patients. Thirteen had routine and 13 had pulsatile bypass with an average pulse pressure of 30 mm Hg. Plasma vasopressin levels were significantly elevated during bypass in both groups, but were lower with pulsation (66 +/- 11 vs 36.3 pg/ml, p less than 0.05). Epinephrine levels increas...