Audrey Adji
Victor Chang Cardiac Research Institute
Non-Invasive assessment of arterial stiffness in advanced heart failure patients supported with mechanical heart assist device in association with their management and outcomes
#Cardiovascular
How will the SphygmoCor® technology enable, enhance, or accelerate your research?
Patients with continuous flow heart assist device are chronically exposed to continuous blood flow with minimal arterial pulsatility that decreases the cyclical stretch of the arterial wall and hence has been associated with increased arterial stiffness. There are a few studies, including from our group, that show how arterial stiffness and blood pressure profile are implicated in adverse events of the heart assist devices [Adji et al. ASAIO J 2022;68:925-931]. Therefore it is important to acquire longitudinal data to investigate the contributory factors associated with changes in large artery stiffness in these patients. Detailed descriptions of these changes are needed in order to gain a better understanding of patients’ hemodynamics and blood pressure control. The SphygmoCor technology will be utilised to develop a novel routine guideline to measure blood pressure using a non-invasive cuff-based device and to integrate this protocol with other heart function markers to improve patient management by health care providers and its association with device function. We previously published in a pilot study using SphygmoCor to estimate pump efficiency based on the blood pressure and heart-pump custom data acquisition system [Jain et al. Circ Heart Fail 2019;12(10):e006191]. Our proposed study intends to measure peripheral and central blood pressure non-invasively and estimate arterial stiffness using carotid femoral pulse wave velocity, using the SphygmoCor technology. Studies have found that non-invasive measurements of arterial stiffness proved to be strong prognostic parameters in heart failure patients, and our proposed study intends to extend its application into advanced heart failure supported by the heart assist device.
Executive Summary
About half of advanced heart failure patients waiting for transplantation require mechanical circulatory support or heart assist device to keep them alive. These device-supported patients are facing potentially fatal outcomes associated with device failure or stroke. To increase survival and quality of life of heart failure patients implanted with heart assist device, it is important to improve measures of circulatory function, including blood pressure and arterial stiffness, using non-invasive methods. Current International Society of Heart and Lung Transplantation guidelines recommend a mean arterial pressure of ≤80 mmHg in these patients, measured reliably by Doppler. Despite these recommendations with focus on blood pressure, only 70% patients maintained mean pressure of <85 mm Hg, suggesting significant ongoing challenges in blood pressure management. Elevated blood pressure has been found to reduce device flow output and decrease cardiac output resulting in less effective pump function as well as promoting pump thrombosis which may result in stroke. Additionally, active management of blood pressure has been shown to decrease cerebrovascular accident or stroke rates. The proposed study aims to understand the challenge in controlling blood pressure and the arterial stiffness profile in this unique cohort, to achieve better control of blood pressure, therefore reducing device-related complications and other adverse events. The objective is to reliably and efficiently assess overall hemodynamic state, while patients are actively supported by the heart assist device. The finding is particularly vital with the new generation of heart assist devices that are being tested and introduced to the market.
Research Setting
St Vincent’s Hospital Sydney, is the oldest and largest heart transplant unit in Australia. It has the greatest experience in heart assist support device in the Southern Hemisphere. This project will make the most of this leadership in research and clinical translation in this field. St Vincent’s Hospital Sydney also has the largest number patients supported by heart assist devices in Australia. Currently St Vincent’s Hospital performs 20-30 heart assist device implantation per year, and these implanted patients are seen in a dedicated Heart Lung Clinic which runs weekly. The Victor Chang Cardiac Research Institute, which I am also associated with, will be the key infrastructure support to the project. I have the expertise of utilising the SphygmoCor technology for the last 20 years for arterial stiffness and central blood pressure measurement, and I am know as an expert of arterial stiffness across St Vincent’s Health Sydney precinct including the Victor Chang Cardiac Research Institute and Garvan Medical Research Institute. I have collaboration with other departments across St Vincent’s Hospital, including cardiology, endocrinology, rheumatology, nephrology, which allow me to perform comparative studies related to arterial stiffness and cardiovascular risk in different diseases and conditions. While our principal proposal will focus on a cohort of advanced heart failure supported with heart assist device, we will also be able to include measurement of arterial stiffness in advanced heart failure patients being worked up for transplantation and those post transplantation.