aPWV

Salvete omnes,

Yesterday I went to a biomedical engineering seminar on aortic pulse wave velocity (aPWV) and how it measures aortic stiffness. It also covered the value of this test in the diagnosis of cardiovascular disease. Two methods of determining the aPWV are under research and includes using an MRI or an ultrasound and then matching the results up against the EKG (specifically the QRS complex since that is what creates a pulse, the QRS complex indicates the depolarization of the ventricles). The advantages of using one of the above methods is that it is both noninvasive and relatively cheap.

Here is a quote from a Medscape article titled, "Aortic Pulse Wave Velocity" which is from the The American Journal of Geriatric Cardiology which explains the basic hemodynamic concepts involved:

"In the absence of widely used noninvasive aortic blood pressure measurements,[3] PWV may be an available method to evaluate the status of central arteries. During systole, the contraction of left ventricular myocardium and the ejection of blood into the ascending aorta acutely dilate the aortic wall and generate a pulse wave that propagates along the arterial tree at a finite speed. This propagation velocity constitutes an index of arterial distensibility and stiffness: the higher the velocity, the higher the rigidity of the vascular wall and the lower the distensibility.[3]
The pressure pulse generated by ventricular ejection is propagated throughout the arterial tree at a speed that is determined by the elastic and geometric properties of the arterial wall and the characteristics (density) of the contained fluid (blood). Since blood is an incompressible fluid and is contained in elastic conduits (arteries), the energy propagation occurs predominantly along the walls of the arteries and not through the incompressible blood. Thus, the properties of the arterial wall, its thickness, and the arterial lumen diameter are the major factors influencing PWV. The relationships between PWV, transmural pressure, wall tension and distensibility have been formalized in many mathematic models. In most of them, the arterial segment studied is considered as a tube either with a thin or a thick vascular wall. Inside this cylindrical tube, there is a positive relationship between the change in pressure and the change in volume (V). The latter is usually expressed per unit length and then evaluated in terms of changes in diameter or radius, considering the length of the tube as constant. In such conditions, PWV may be defined according to the Moens-Korteweg and the Bramwell and Hill equations.[3]"

Okay, well I thought it was interesting anyway...you all probably didn't. Hopefully you read the above article and learned something anyway though. If you are interested in reading the rest of the article, you can go to http://www.medscape.com/viewarticle/443202 .

Stay safe everyone,
Bravomedic out.