Researchers in the  Division of Imaging Sciences & Biomedical Engineering  at King’s have discovered an improved method for measuring the presence of an obstruction when the blood flows out of the heart.

When the heart beats, blood is squeezed from the heart into the aorta. As it leaves the heart, it crosses the valve, and the pressure of the blood drops.  The amount the blood pressure drops can tell doctors a lot about how the valve is functioning and is a powerful diagnostic technique.

Cardiologists currently use non-invasive images to measure a peak velocity value in the jet of blood leaving the heart, and then use a physical principle (called Bernoulli’s Principle) to estimate for the pressure drop when the jet leaves the heart through the aortic valve.

Led by  Dr Pablo Lamata  and  Dr David Nordsletten , the team at King’s have been looking into improving this method of calculating blood pressure, using non-invasive imaging techniques. Their recent results, published in  Circulation: Cardiac Imaging  illustrates that using the Bernoulli principle can cause inaccuracies in blood pressure measurements in diseased hearts where the valves are narrowed, irregularly shaped or where the valve doesn’t work properly.

These inaccuracies are caused by the faulty valves altering the speed of the blood, causing skewed blood jets in the aorta. The team found that a more accurate and precise non-invasive estimation of the peak pressure drop, beyond Bernoulli’s principle, is now possible by a more comprehensive examination of blood velocity.

Using the team’s methods to control for the variations in speed caused by faulty valves, it is hoped that clinicians may be able to better diagnose and treat patients with valve stenosis and other conditions where the flow of blood from the heart is constricted. Further research could look to establish which pressure drops signify serious problems with the heart and determine which pressure biomarker holds the most importance in predicting clinical outcomes.

The full paper is available  here