scholarly journals Effects of Acute Pump Speed Changes on Cerebral Hemodynamics in Patients With an Implantable Continuous-Flow Left Ventricular Assist Devices

2021 ◽  
pp. 831-839
Author(s):  
M. Konarik ◽  
M. Sramko ◽  
Z. Dorazilova ◽  
M. Blaha ◽  
I. Netuka ◽  
...  

Mechanical circulatory support (MCS) with an implantable left ventricular assist device (LVAD) is an established therapeutic option for advanced heart failure. Most of the currently used LVADs generate a continuous stream of blood that decreases arterial pulse pressure. This study investigated whether a change of the pulse pressure during different pump speed settings would affect cerebral autoregulation and thereby affect cerebral blood flow (CBF). The study included 21 haemodynamically stable outpatients with a continuous-flow LVAD (HeartMate II, Abbott, USA) implanted a median of 6 months before the study (interquartile range 3 to 14 months). Arterial blood pressure (measured by finger plethysmography) was recorded simultaneously with CBF (measured by transcranial Doppler ultrasound) during baseline pump speed (8900 rpm [IQR 8800; 9200]) and during minimum and maximum tolerated pump speeds (8000 rpm [IQR 8000; 8200] and 9800 rpm [IQR 9800; 10 000]). An increase in LVAD pump speed by 800 rpm [IQR 800; 1000] from the baseline lead to a significant decrease in arterial pulse pressure and cerebral blood flow pulsatility (relative change −24 % and −32 %, both p < 0.01), but it did not affect mean arterial pressure and mean CBF velocity (relative change 1 % and −1.7 %, p=0.1 and 0.7). In stable patients with a continuous-flow LVAD, changes of pump speed settings within a clinically used range did not impair static cerebral autoregulation and cerebral blood flow.

Angiology ◽  
2020 ◽  
Vol 72 (1) ◽  
pp. 9-15
Author(s):  
Pavel Poredos ◽  
Mateja K. Jezovnik ◽  
Rajko Radovancevic ◽  
Igor D. Gregoric

The endothelium plays a crucial role in maintaining cardiovascular homeostasis. Shear stress generated by flowing blood regulates the release of substances that provide adequate tissue perfusion. The extent of damage to endothelial cells depends on locally disturbed shear stress caused by the deteriorated flow. Patients with heart failure have reduced cardiac output, which results in reduced blood flow and negative shear stress. Reduced shear stress also affects microcirculation and reduces tissue perfusion. Consequently, the production of free oxygen radicals is increased and bioavailability of nitric oxide is additionally decreased. Therefore, endothelial dysfunction is involved in the progression of heart failure and cardiovascular events. Left ventricular assist devices (LVAD) are used for the treatment of patients with advanced heart failure. Older pulsatile flow LVADs were mostly substituted by continuous-flow LVADs (cf-LVADs). Despite the advantages of the cf-LVADs, the loss of pulsatility leads to different complications on the micro- and macrovascular levels. One of the pathogenetic mechanisms of cardiovascular complications with cf-LVADs may be endothelial dysfunction, which after the implantation of the device does not improve and may even deteriorate. In contrast, the pulsatile pattern of LVADs on blood flow could preserve endothelial function.


2016 ◽  
Vol 22 (8) ◽  
pp. S108-S109
Author(s):  
Christopher T. Sparrow ◽  
David S. Raymer ◽  
Shree L. Radhakrishnan ◽  
Michael E. Nassif ◽  
Justin M. Vader ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document