Hitachi Aloka Medical announced its collaboration with Alan Fraser of the Cardiff University School of Medicine to establish industry standards for the development and evaluation of diagnostic tools that examine how the heart interacts with larger arteries.
Cardiologists from 13 centres in Europe have collaborated in the ETIC study, coordinated from Cardiff, to pool results from eTRACKINGof carotid arteries using Hitachi Aloka Medical vascular transducers in more than 2000 normal subjects. Increased arterial stiffness – particularly in the carotid arteries – causes increased pressure and load to be placed on the heart. This process is understood to occur because increased arterial stiffness – which is measured by eTRACKING – modifies the timing of wave reflections.
For example, during ventricular ejection a forward pressure wave is generated which is then reflected back from the arterial tree. In patients with increased arterial stiffness, the reflected wave travels more quickly back to the heart – meaning that when it arrives the aortic valve has not had a chance to close (i.e. it arrives during LV ejection), so the central systolic blood pressure and LV afterload are both increased. This causes the heart muscle to increase in size (left ventricular hypertrophy). Over time, the heart’s increased muscle mass will also cause slow relaxation of the heart muscle and difficulty in filling.
The interactions between the heart and reflected waves have been studied using the special methods developed by Hitachi Aloka Medical, for estimating the local direction and amplitude of waves in an artery – Wave Intensity – via simultaneous recordings of diameter (with pressure) and velocity. The results have given clinicians new insights into how arteries and ventricles interact, especially in the presence of arterial disease.
Together, these two new diagnostic tools – eTRACKINGand Wave Intensity – provide powerful methods for understanding the effects of drugs on altering the interactions between the heart and arteries. It is now possible to discriminate between the peripheral and central effects of drugs, which will help clinicians to choose treatments for patients that are most likely to reduce the risk of heart failure. Drugs that modify the timing as well as the amplitude of reflected waves may be most effective in reducing stress on the heart.
“We have already successfully tested the Hitachi Aloka diagnostic tools for Wave Intensity and eTRACKING – contributing to breakthroughs in our concepts of the mechanisms of cardiovascular disease and ventricular-arterial coupling,” said Fraser.