Project Overview

The objective of our project is to investigate if women with carotid stenosis (CAS) have impaired cerebral blood flow (CBF) regulation in different regions of their brain. Specifically, we hypothesize that women with more severe CAS will have greater impairments in their ability to maintain CBF during rapid reductions in blood pressure. We predict this will be specific to the side of the brain that has the plague build-up. A secondary objective is to test how CBF regulation is related to resting (i.e., baseline) measures of brain health. For example, we hypothesize that areas with impaired CBF regulation will also have low CBF at rest and impaired ability to use oxygen as a fuel for the neurons.

The researchers on this project have received funding from the Canadian government to run a project on patients with CAS and their resting brain health, by using novel and unique brain imaging technology. These technologies, called magnetic resonance imaging (MRI) and positron emission tomography (PET), allow us to investigate resting measures of CBF and oxygen usage in the brain. We are proposing to add an additional testing day to assess regional CBF regulation using MRI and “”oscillatory lower-body negative pressure”” (OLBNP). OLBNP is a common technique to mimic the blood pressure drop that occurs when you stand up. OLBNP does this in a controlled manner with minimal movement, discomfort, and risk for the participant. The set-up includes placing the participant in an air-tight MRI-compatible box that is attached to a vacuum. When the vacuum turns on, it creates a “”negative pressure”” that pulls the blood toward the feet for a period of ~12.5s. By turning the vacuum on and off we can assess how different regions of the brain work o maintain CBF. We will recruit 30 female patients who will be classified into three groups: healthy controls, moderate CAS, and severe CAS. We will also recruit 10 age-matched men with severe CAS.

Principal Investigator

Leena Shoemaker , University of Western Ontario

Partners and Donors

Heart and Stroke Foundation