Scientists from the Dublin, Ireland-based RCSI University of Medicine and Health Sciences report the development of a new lab-based model of a heart and circulatory system. The goal is to help test devices to treat patients with one of the most common forms of heart failure.

The study (“In vitro benchtop mock circulatory loop for heart failure with preserved ejection fraction emulation”), which appears in Frontiers of Cardiovascular Medicine, used two different types of circulatory, models including a silicone heart model. The research was carried out by RCSI in collaboration with the National College of Art and Design (NCAD).

There are two common types of heart failure: Heart Failure with Preserved Ejection Fraction (HFpEF) and Heart Failure with Reduced Ejection Fraction (HFrEF). Ejection fraction is the measurement used to determine the heart’s ability to pump oxygen-rich blood through the body.

In recent years, the number of patients presenting with heart failure with normal or preserved ejection fraction measurement is increasing, most likely due to the increase in the prevalence of common risk factors, including old age, hypertension, and obesity. Women are at greater risk than men.

In this research from RCSI, a model called a “mock circulatory loop” was developed to mimic both a healthy heart and a heart in failure with preserved ejection fraction. The model can test devices to examine the left atrium, the top chamber responsible for receiving oxygen-rich blood from the lungs, as well as the left ventricle, the lower chamber responsible for pumping the oxygen-rich blood around the body, according to the researchers.

“In this work, a novel mock circulatory loop (MCL) is presented that is capable of simulating both healthy cardiac function and HFpEF. This MCL differs from others presented in the literature as it features two independently actuated heart chambers, representing the left atrium and the left ventricle. This is an important improvement over other designs as it allows for potential HFpEF treatments to be examined, not just in relation to their effect on the left ventricle but also on the left atrium,” the investigators wrote.

Model developed to test for new circulatory support devices

“The aim of this work was to show that novel MCL designs could be developed to allow for testing of new mechanical circulatory support devices for the treatment of HFpEF. Two loop configurations are presented, one featuring hard PVC cylindrical chambers and one that features soft silicone chambers which are anatomically analogous to the native heart.

“We show that both MCLs are capable of simulating the onset of HFpEF with a sustained increase in diastolic pressure of 62.03% and a sustained decrease in end diastolic volume (EDV) of 14.24%.”

“Half of the patients presenting with heart failure have heart failure with preserved ejection fraction and the numbers are increasing in the developed world in particular due to the increase in the prevalence of risk factors,” said Aamir Hameed, MD, senior author on the study, lecturer in the department of anatomy and regenerative medicine, and a principal investigator with the tissue engineering research group at RCSI. “The condition can be difficult to treat with medicines and is causing a considerable burden to health services throughout the world.

“The development of this lab-based model is a milestone in heart failure research as it enables devices to be tested that have the potential to treat a condition that affects millions of people around the world, improving their quality of life and reducing the burden on health services.”

The research was funded by Enterprise Ireland, which is supporting the development of the RCSI pipeline spin-out company, Pumpinheart, which plans to commercialize a novel medical device for the treatment of heart failure with preserved ejection fraction.