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

Introduction: Heart failure with a reduced Ejection Fraction (HFrEF) is a progressive disease with a low 5-year survival of <50%, affecting 23 million people. It is characterized by adverse remodelling of the left ventricle (dilated cardiomyopathy). For every 5% increase in EF there is a 13% decrease in mortality. Pharmacological treatment and cardiac resynchronisation therapy have proven beneficial for survival. However, HFrEF still remains a progressive deadly disease. In HFrEF myocardial wall stress is increased and wall stress reduction might prevent or even reverse remodelling. Some devices, superficially constraining the dilated heart, have shown EF-increase and promote reverse remodelling. However, current devices cannot adapt to left ventricle reverse remodelling or apply different restraints to regional parts of the ventricle which limits these beneficial effects, thus limiting long-term effect of this treatment. Furthermore, regional wall stresses during a full cardiac cycle in humans are unknown.

Aim: We aim to develop a device to reduce left ventricular regional wall stresses, prevent further dilatation, increase the ejection fraction and guide reverse remodelling.

Methods: First, we will measure wall stresses during the full cardiac cycle. Next, we will develop a simplified mathematical model of the left ventricle to characterize the weakened wall and to determine optimal material properties and configuration of a device.Using a synthetic heart model adjusted to various HFrEF stages, we will obtain wall stresses of the left ventricle constraint with smart materials in different configurations. Possible side effects on diastolic filling, pressure build-up, flow and coronary arteries will be examined.