Mechanically reducing regional left ventricular wall stress and improving ejection fraction in heart failure patients

Objectives: Heart failure with reduced Ejection Fraction (HFrEF) is a pro-gressive disease with a low 5-year survival of <50%, which affects 23 million people worldwide. It is characterized by adverse remodeling of the left ventricle (dilated cardiomyopathy) due to an increase in filling pressures and myocardial wall stress. Pharmacological treatment and cardiac resynchronisation therapy have proven beneficial for survival. For patients with end-stage heart failure, a heart transplant or Left Ventricular Assist Device can be considered. A shortage of donors, patient selection and major downsides such as invasiveness and drive-line infections limit the use of these treatments. Research has shown a 13% decrease in mortality for every 5% increase in left ventricular ejec-tion fraction. Therefore, we developed a smart memory alloy configura-tion in order to increase the ejection fraction and obtain an increase of 3,5% in a bench model. To cope with ongoing left ventricular dilatation and rise in wall stress, this should be combined with adjustable and measurable ventricular restraint therapy. Our first aim is to measure local wall stress during a full cardiac cycle. Next, we aim to develop a mathematical model of the left ventricle to characterize the left ventricle in HFrEF patients. Methods: We will characterize in vivo wall stresses during the full car-diac cycle using Transesophageal Echocardiography and a left ventricular pressure catheter in 10 patients undergoing cardiac surgery for heart failure. With these parameters, we will develop a simplified mathemati-cal model of the left ventricle and we will improve our bench model for experimental testing. Results: This research will provide a characterization of the weakened left ventricular wall and the determination of optimal smart material properties and configuration of the cardiac assist device. Discussion: With this information, a patient-specific HFrEF treatment device will be developed combining active cardiac support and restraint therapy