Scientists have devised a method to obtain critical information about cardiac function - using machines that help failing hearts circulate blood. The new approach could offer clinicians a more accurate method for measuring heart function after cardiogenic shock (a condition in which the organ is suddenly unable to pump enough blood to meet the body's needs), and may pave the way to self-contained, automatic mechanical circulatory support systems. After a heart attack, some patients suffer from potentially life-threatening cardiogenic shock. Few treatments exist beyond implanted devices to improve circulation, such as the Impella from Abiomed, which pulls blood from a heart chamber called the left ventricle into the main artery of the body, the aorta. Techniques that evaluate whether an implant is working to improve cardiac output are lacking - motivating Brian Chang and colleagues to investigate potential cross-talk between pump performance and heart function. The researchers narrowed in on the relationship between pump motor current and pressure gradients across the device (both available from the Impella's control unit) as a good substitution for an established metric of cardiac function called left ventricular end diastolic pressure (LVEDP, the pressure in the heart chamber at its fullest point before contracting). In pig models and artificial circulating systems called circulatory loops, the pump measurements correlated well with LVEDP. Notably, information from an implanted Impella pump was more sensitive than established clinic protocols for inferring LVEDP for a patient being treated for cardiogenic shock in a clinical setting.
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Journal
Science Translational Medicine