Assessing Cerebrovascular Hemodynamics Using Transcranial Doppler in Patients with Mechanical Circulatory Support Devices

Abstract

BACKGROUND AND PURPOSE: Mechanical circulatory support (MCS) devices are commonly used in heart failure patients. These devices carry risk for presumably embolic and additionally hemorrhagic stroke. Alterations in blood flow play a key role in stroke pathophysiology, and we aimed to learn more about hemodynamic compromise. In this study, we used transcranial Doppler (TCD) ultrasound to define hemodynamics of commonly used nonpulsatile MCS devices, as well as pulsatile devices, with special attention to the total artificial heart (TAH). METHODS:From 2/2013 through 12/2016, we prospectively enrolled patients with MCS who underwent TCD imaging. We analyzed TCD parameters, including peak systolic velocity, end-diastolic velocity, pulsatility indices (PIs), and number of highintensity transient signals. Waveform morphologies were compared between various MCS devices. RESULTS: We performed 132 TCD studies in 86 MCS patients. Waveforms in patients supported by venoarterial-extracorporeal membrane oxygenation demonstrated continuous flow without clear systolic peaks with an average (±SD) PI of .43 (±.2). PIswere low in patients with continuous-flow left ventricular assist devices with a mean PI of .32 (±.13). Impella patients had morphologically distinct pulsatile waveforms and a higher mean PI of .65 (±.24). In intra-arterial balloon pump patients, mean PI was 1.01 (±.16) and diastolic upstrokes were pronounced. In TAH patients, mean middle cerebral artery velocity of 79.69 (±32.33) cm/seconds and PI of .74 (±.14) approached normal values. CONCLUSION: TCD can detect characteristic waveforms in patients supported by various MCS devices. These device-specific TCD patterns are recognizable and reproducible.

Transcranial Doppler Ultrasound for Monitoring the Cerebral Hemodynamic Changes and Prognosticating Outcomes in Venoarterial Extracorporeal Membrane-Oxygenated Patients

“…As the cardiac systolic function changed, the patient's cerebral hemodynamics and PI value were also seen to change ( Figure 4 ). This finding is consistent with several previous studies [ 19 , 21 , 22 ]. Kavi et al [ 19 ] pointed out that the existence of low PI can be explained by the pulse produced by a severely weakened but mildly preserved cardiac systolic function, and such a patient should not be considered for either cerebral vasodilation or cerebral circulation arrest protocols.…”

A Standardized Multimodal Neurological Monitoring Protocol-Guided Cerebral Protection Therapy for Venoarterial Extracorporeal Membrane Oxygenation Supported Patients

“…Understanding the changes in CBF is helpful to detect new vascular injury during ECMO support and to optimize cerebral perfusion. TCD and TCCD have been applied to stroke, TBI, hypoxic-ischemic encephalopathy, and neurological monitoring during ECMO support ( 36 – 39 ). Point-of-care ultrasound (PoCUS) visualization management of ECMO patients has played an important role in identifying indications, catheterization, flow adjustment, volume management, cardiac function evaluation, etc.…”

Narrative Review of Neurologic Complications in Adults on ECMO: Prevalence, Risks, Outcomes, and Prevention Strategies

“…TCD ultrasound offers significant diagnostic value for patients supported by ECMO, providing direct measurements of the pattern of cerebral blood flow, hemodynamic reserve, and microembolic signals (MESs). Waveforms in patients supported by VA ECMO were demonstrated as continuous flows without clear systolic peaks ( 58 ). Furthermore, TCD ultrasound can be used to calculate mean flow velocities and pulsatility indexes for patients on VA ECMO ( 59 ).…”