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Cullen Buchanan1, Manreet Kanwar2, John R Cockcroft3
1Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
Insights
Left ventricular assist devices (LVADs) improve survival but cause hypertension and stroke due to non-physiologic pulses. Addressing these side effects is crucial for enhancing patient quality of life and outcomes.
Area of Science:
- Cardiovascular Medicine
- Biomedical Engineering
Background:
- Current left ventricular assist devices (LVADs) significantly improve survival in advanced heart failure patients.
- However, LVAD use is associated with adverse effects like hypertension, stroke, and limited functional capacity.
Purpose of the Study:
- To investigate the link between non-physiologic pulse from LVADs and adverse patient outcomes.
- To explore the mechanisms behind LVAD-induced hypertension and stroke.
- To identify potential avenues for improving LVAD technology and patient quality of life.
Main Methods:
- Analysis of patient data regarding LVAD complications.
- Review of physiological pathways affected by non-physiologic pulsatility.
- Examination of sympathetic nerve activity and baroreceptor-mediated responses.
Main Results:
- LVAD patients exhibit elevated sympathetic nerve activity and hypertension, increasing stroke risk.
- Chronic exposure to non-physiologic pulses contributes to a hyperadrenergic state.
- Cerebral autoregulation appears preserved despite the absence of a physiologic pulse.
Conclusions:
- LVAD-related hypertension and stroke are significant challenges impacting patient morbidity and mortality.
- The non-physiologic pulse generated by current LVADs is a key factor contributing to these complications.
- Advancements in device technology are needed to mitigate these side effects and improve long-term patient outcomes.
New Findings:
LVAD patients are predisposed to hypertension which may increase the risk of stroke. Hypertension may result from markedly elevated levels of sympathetic nerve activity, which occurs through a baroreceptor-mediated pathway in response to chronic exposure to a non-physiologic (and reduced) pulse. Cerebral autoregulatory processes appear to be preserved in the absence of a physiologic pulse. Nevertheless, the rate of ischemic/embolic and hemorrhagic stroke is unacceptably high and is a major cause of morbidity and mortality in these patients. Despite normalization of a resting cardiac output, LVAD patients suffer from persistent, severe reductions in functional capacity.
Abstract:
Current generation left ventricular assist devices (LVADs) have led to significant improvements in survival compared to medical therapy alone, when used for management of patients with advanced heart failure. However, there are a number of side-effects associated with LVAD use, including hypertension, gastrointestinal bleeding, stroke, as well as persistent and severe limitations in functional capacity despite normalization of a resting cardiac output. These issues are, in large part, related to chronic exposure to a non-physiologic pulse, which contributes to a hyperadrenergic environment characterized by markedly elevated levels of sympathetic nerve activity through a baroreceptor-mediated pathway. In addition, these machines are unable to participate in, or contribute to, normal cardiovascular/autonomic reflexes that attempt to modulate flow through the body. Efforts to advance device technology and develop biologically sensitive devices may resolve these issues, and lead to further improvements in quality-of-life, functional capacity, and ultimately, survival, for the patients they support.
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