Aortic valve dynamics and blood flow control in continuous flow left ventricular assist devices

2017 ◽  
Author(s):  
Viswajith S. Vasudevan ◽  
Yu Wang ◽  
Marwan A. Simaan
Keyword(s):  
Blood Flow ◽  
Aortic Valve ◽  
Continuous Flow ◽  
Left Ventricular ◽  
Ventricular Assist Devices ◽  
Left Ventricular Assist Devices ◽  
Ventricular Assist ◽  
Left Ventricular Assist ◽  
Blood Flow Control ◽  
Valve Dynamics

Pulse assessment is important with blood pressure measurement in individuals with continuous flow left ventricular assist devices

2020 ◽  
pp. 039139882092702
Author(s):  
Hernan G Marcos-Abdala ◽  
Ana S Cruz-Solbes ◽  
Imad Hussain ◽  
Barry Trachtenberg ◽  
Guha Ashrith ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Aortic Valve ◽  
Continuous Flow ◽  
Left Ventricular ◽  
Ventricular Assist Devices ◽  
Left Ventricular Assist Devices ◽  
Ventricular Assist ◽  
Assist Devices ◽  
Left Ventricular Assist ◽  
Valve Opening

While Doppler and cuff blood pressure techniques are prevalent methods of assessing blood pressure in patients with continuous flow left ventricular assist devices, the impact of pulsatility on measurement is not well established. Retrospective chart analysis of clinical variables including pulse perception, blood pressure (Doppler and standard cuff), and aortic valve opening on echo at clinic visit were abstracted. Stable outpatients on continuous flow left ventricular assist devices support with concomitant portable echo assessment were included. Mean average difference was calculated and Pearson’s correlation performed for all those patients who had both Doppler and cuff pressure obtained. In all, 74 Heartmate-II patients with a median time from implant of 380 days were analyzed. A pulse was perceived in 82% of patients with persistent aortic valve opening on portable echo and also in 30% of those who had a persistently closed aortic valve. The mean average difference between the Doppler and systolic cuff pressure was ~13 mmHg ( r = 0.5, p = 0.004) when a pulse was present and ~11 mmHg when aortic valve was open ( r = 0.68, p < 0.0001). Pulse presence seems to reflect aortic valve opening a majority of the time but not always. In the presence of a prominent pulse or persistent aortic valve opening, the Doppler pressure seems to be more reflective of a systolic pressure than mean perfusion pressure. Hence, assessment of pulsatility needs to be incorporated into blood pressure measurement methods for patients with continuous flow left ventricular assist devices.

Endothelial Function in Patients With Continuous-Flow Left Ventricular Assist Devices

Angiology ◽  
2020 ◽  
Vol 72 (1) ◽  
pp. 9-15
Author(s):  
Pavel Poredos ◽  
Mateja K. Jezovnik ◽  
Rajko Radovancevic ◽  
Igor D. Gregoric
Keyword(s):  
Heart Failure ◽  
Blood Flow ◽  
Shear Stress ◽  
Continuous Flow ◽  
Tissue Perfusion ◽  
Left Ventricular ◽  
Ventricular Assist Devices ◽  
Left Ventricular Assist Devices ◽  
Ventricular Assist ◽  
Left Ventricular Assist

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.

Continuous-Flow Left Ventricular Assist Devices and the Aortic Valve: Interactions, Issues, and Surgical Therapy

2020 ◽  
Vol 17 (4) ◽  
pp. 97-105 ◽  
Author(s):  
Matthew L. Goodwin ◽  
Christopher M. Bobba ◽  
Nahush A. Mokadam ◽  
Bryan A. Whitson ◽  
Michael Essandoh ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Surgical Therapy ◽  
Continuous Flow ◽  
Left Ventricular ◽  
Ventricular Assist Devices ◽  
Left Ventricular Assist Devices ◽  
Ventricular Assist ◽  
Assist Devices ◽  
Left Ventricular Assist
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