BRAIN-HEART Ultrasound Study Normative Values for Transcranial Doppler Based Cerebral Blood Flow Assessment

There is a dire need to establish normative values for transcranial Doppler(TCD) derived cerebral blood flow parameters for each type of Mechanical circulatory support (MCS) device and explore the relationship between the MCS device's systemic flow dynamics and TCD based cerebral flow(CBF) parameters TCD derived cerebral blood flow parameters can then be investigated as targets used to titrate systemic flow dynamics from MCS. Having target flow rates titrated to patient specific condition using TCD may help avoid both hypoperfusion as well as the possibility of hyperemia reperfusion injury contributing to neurological morbidity. We propose a multicenter study to gather normative data on TCD derived CBF and MCS systemic dynamics for a wide range of patient demographics. Such data collection is only possible with multi-center collaboration given the small volume of patients with MCS patients in each center.

The Mechanical circulatory support (MCS) devices are temporary devices that enable complete and immediate cardiopulmonary support in settings of cardiac arrest and cardiogenic shock. The different MCS devices differ in their operating principles and generate different systemic flow patterns (pulsatile vs non- pulsatile, flow volumes, Peak flow rates, and PI). Researchers have studied different MCS devices like VA Extra Corporeal Mebrane Oxygenation(ECMO), left ventricular assist device (LVAD), and Impella and their effect on cerebral flow and complication profiles using various neuromonitoring techniques including TCD . Most such studies were small single-center studies that added to the understanding of different flow rates and characteristics with different MCS devices but were not adequately powered or designed to establish normative values of TCD derived CBF measures in this special population. There is a dire need to establish normative values for each type of MCS device and explore the relationship between the MCS device's systemic flow dynamics and TCD derived cerebral flow. These normative values then can be used to assess the association of TCD derived CBF patterns with occurrence of neurological complications related to abnormal CBF in patients receiving MCS devices and advice on patient specific MCS parameters titrated using TCD derived parameters. Having target flow rates in MCS patients will help avoid both hypoperfusion as well as the possibility of hyperemia reperfusion injury contributing to neurological morbidity. Such data collection is only possible with multi-center collaboration given the small volume of patients with MCS patients in each center.

Eligibility Criteria:
Inclusion Criteria:

* \>18 years old on the day of enrollment
* Mechanical circulatory support

  a. Left Ventricular Assist Device \[HeartMate-III\] in antegrade flow i. Critically ill ii. With and without pulsatility b. Impella antegrade flow c. VA-ECMO (VA-ECMO) is a temporary mechanical circulatory support system that enables complete and immediate cardiopulmonary support in the setting of cardiogenic shock and cardiac arrest) retrograde flow usual with femoral cannulation or antegrade flow if centrally cannulated
* Patient must be in the intensive care unit or in patient for the intervention to be performed

Exclusion Criteria:

* Known cerebrovascular disease or know angiographic abnormalities based on preexisting computed tomography angiography, digital subtraction angiography or transcranial Doppler prior to this hospitalization that will significantly affect Transcranial Doppler (TCD) parameters. Patients with abnormalities not likely to affect TCD parameters or known normal TCDs despite abnormal cerebral hemodynamic studies will still be included
* Pre-Existing neurological deficits impairing quality of life
* Absence of temporal windows
* Presence of skull defects that may affect the feasibility of TCD windows
* Co-existing dialysis or other forms of renal replacement therapy
* Pregnant patients
* Patients on palliative care pathway awaiting de-escalation
* Patient on comfort care