Effect of pulsatile and nonpulsatile flow on cerebral perfusion in patients with left ventricular assist devices

Cornwell, William K.; Tarumi, Takashi; Aengevaeren, Vincent L.; Ayers, Colby; Divanji, Punag; Fu, Qi; Palmer, Dean; Drazner, Mark H.; Meyer, Dan M.; Bethea, Brian; Hastings, Jeffrey L.; Fujimoto, Naoki; Shibata, Shigeki; Zhang, Rong; Markham, David W.; Levine, Benjamin D.

doi:10.1016/j.healun.2014.08.013

Cited by 61 publications

(33 citation statements)

References 39 publications

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“…14 The structural changes within the aorta noted in our study may partly explain the baseline physiological changes in cerebral perfusion noted by these investigators. Additional studies are needed to determine the potential physiological compensatory responses to such structural changes within the vessels in the cerebral and other vascular beds.…”

Section: Discussionsupporting

confidence: 57%

Changes in Aortic Wall Structure, Composition, and Stiffness With Continuous-Flow Left Ventricular Assist Devices

Ambardekar

Hunter

Babu

et al. 2015

Circ: Heart Failure

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Background— The effects of nonpulsatile flow on the aorta are unknown. Our aim was to examine the structure of the aorta from patients with continuous-flow left ventricular assist devices (LVADs) and directly measure aortic wall composition and stiffness. Methods and Results— Age-matched aortic wall samples were collected from consecutive patients with heart failure (HF) at the time of transplantation and compared with nonfailing donor hearts. An unbiased stereological approach was used to quantify aortic morphometry and composition, and biomechanical testing was performed to determine the stress–strain relationship of the vessel. Data were obtained from 4 patients without a left ventricular assist device (HF group: mean age, 58.3±8.0 years), 7 patients with a continuous-flow LVAD (HF+LVAD group: mean, 57.7±5.6 years), and 3 nonfailing donors (mean, 53.3±12.9 years). Compared with HF, the aortic walls from HF+LVAD had an increase in wall thickness, collagen, and smooth muscle content accompanied by a reduction in elastin and mucinous ground-substance content. Stress–strain curves from the aortas revealed increased vessel stiffness in HF+LVAD compared with HF and nonfailing. The physiological modulus of the aorta progressively stiffened from 74.3±5.5 kPa in the nonfailing to 134.4±35.0 kPa in the HF to 201.7±36.4kPa in the HF+LVAD groups ( P <0.001). Conclusions— Among continuous-flow LVAD patients without aortic valve opening, there are changes in the structure and composition of the aorta as well as an increase in aortic wall stiffness compared with age-matched HF patients and nonfailing donors. Further studies examining the role of nonpulsatile blood flow on aortic function and the potential resultant systemic sequelae are needed.

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Section: Discussionsupporting

confidence: 57%

Changes in Aortic Wall Structure, Composition, and Stiffness With Continuous-Flow Left Ventricular Assist Devices

Ambardekar

Hunter

Babu

et al. 2015

Circ: Heart Failure

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“…This was recently investigated in a series of patients with continuous flow LVADs, pulsatile flow LVADs, and healthy controls who underwent an exercise challenge while undergoing transcranial Doppler (TCD) ultrasonography. In this study, investigators found that changes in TCD were similar in patients with LVADs and controls arguing against the loss of cerebral auto-regulation [27•]. Other more advanced measures of cerebral auto-regulation, such as direct cerebral auto-regulation with a hypotensive or post-occlusive hyperemic challenge [28], have not been established in this patient population.…”

Section: Hypertension and Stroke In Left Ventricular Assist Devicesmentioning

confidence: 93%

Hypertension and Stroke in Patients with Left Ventricular Assist Devices (LVADs)

et al. 2016

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Stroke is one of the most dreaded complications of left ventricular assist device therapy in patients with end-stage congestive heart failure. There is strong evidence linking anticoagulation and infection with ischemic and hemorrhagic strokes, though recent data has emerged regarding the importance of elevated blood pressure. In the recently completed Heartware Ventricular Assist Device studies, a mean arterial pressure greater than 90 mmHg was associated with greater stroke risk, particularly the hemorrhagic subtype. In this review, we discuss recent evidence regarding deleterious effects of uncontrolled hypertension in patients with left ventricular devices, and propose measurement and management strategies.

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“…However, autoregulation of cerebral flow was preserved in both device types. 67 Another intriguing study using a transparent replica of the HeartMate II left VAD (Thoratec, Inc) at different flow rates showed that pulsatility imposed on the system (in theory by the native heart) may induce disturbance to an otherwise stable flow field with possibly prothrombotic effects. 68 This study is particularly interesting as a newly designed VAD, the HeartMate III (Thoratec Corporation, Pleasanton, CA), which is in clinical trials currently, aims to intermittently introduce pulsatility to a centrifugal pump system (Table 2).…”

Section: Ventricular Assist Devicesmentioning

confidence: 99%

New Management Strategies in Heart Failure

Owens

Brozena

Jessup

2016

Circulation Research

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Effect of pulsatile and nonpulsatile flow on cerebral perfusion in patients with left ventricular assist devices

Cited by 61 publications

References 39 publications

Changes in Aortic Wall Structure, Composition, and Stiffness With Continuous-Flow Left Ventricular Assist Devices

Changes in Aortic Wall Structure, Composition, and Stiffness With Continuous-Flow Left Ventricular Assist Devices

Hypertension and Stroke in Patients with Left Ventricular Assist Devices (LVADs)

New Management Strategies in Heart Failure

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