Assessing endothelial function and providing calibrated UFMD data using a blood pressure cuff

A method of assessing cardiovascular function in a mammal, said method comprising:

• a) determining the systolic and diastolic blood pressure of said mammal wherein said determining the systolic and diastolic blood pressure comprises determining the pulse height as a function of applied external pressure Pm to an artery;
• b) applying a substantially constant external pressure Pm to an artery for a first period of time Tm, to provide a reduced transmural pressure, and determining, over the course of one or more cardiac cycles in said first period of time Tm, changes in pressure in said artery resulting from cardiac activity of said mammal, or an artificially induced arterial pulse, to establish a baseline value for a parameter related to endothelial function in said mammal;
• c) applying an arterial stimulus to said mammal;
• and
• d) applying said substantially constant external pressure Pm to said artery for a second period of time Tm, to provide a reduced transmural pressure, and determining, over the course of one or more cardiac cycles in said second period of time Tm, changes in pressure in said artery resulting from cardiac activity of said mammal, or an artificially induced arterial pulse, to provide a stimulus-affected parameter related to endothelial function in said mammal;
• e) determining a second the systolic and diastolic blood pressure of said mammal, wherein said determining a second systolic and diastolic blood pressure comprises determining the pulse height as a function of applied external pressure Pm to an artery;
• f) fitting the data obtained in step (a) to determine a first model relating pulse height to transmural pressure and using said first non-linear model to convert said baseline value for a parameter related to endothelial function to a baseline value for a parameter related to endothelial function at a reference pressure;
• g) fitting the data obtained in step (e) to determine a second non- linear model relating pulse height to transmural pressure and using said second model to convert said stimulus-affected value for a parameter related to endothelial function to a stimulus-affected parameter related to endothelial function at said reference pressure;
• h) using said baseline value for a parameter related to endothelial function at said reference pressure to calculate baseline arterial lumen area (Ab) or a measure proportional to the area Ab at said reference pressure;
• i) using said stimulus-affected value for a parameter related to endothelial function at said reference pressure to calculate stimulus-affected arterial lumen area (Ar) or a measure proportional to the area Ar at said reference pressure;
• and
• j) determining the equivalent ultrasound-based flow-mediated dilation FMD (uFMD) measure where uFMD is proportional to the square root of the ratio Ar/Ab, and where said baseline values are determined from measurements made when said mammal is not substantially affected by said stimulus and uFMD provides a measure of cardiovascular function in said mammal.