Heart transplantation is performed in high-risk patients. Appropriate selection of patients for transplantation is vital. Increasingly, objective measures of frailty are used to estimate perioperative risks. Various frailty assessment tools have been used to risk-stratify patients referred for heart transplantation, and have been able to predict a range of outcomes. However, current methods are complex, subjective, time consuming and effort-dependant.
Lack of muscle bulk has been investigated as an objective, effort-independent marker of frailty in many different patient populations. Muscle mass has been measured using abdominal CT scan cross-sectional area of the psoas muscle. Recently, ultrasound measurement of the thigh muscle (rectus femoris), has been used to predict outcomes in other patient populations. This measurement is rapid, simple and safe.
This study will explore whether reduced size of the thigh muscle using a simple test will improve the predictive capability of an existing frailty score. This is the first study investigating ultrasound measurement of muscle mass and frailty in patients undergoing heart transplantation. It will also examine whether patients who have low thigh muscle mass have worse outcomes after heart transplantation.
The incorporation of a rapid, objective, simple, effort-independent, bedside measurement of muscle mass may enhance risk stratification in transplant patients. In the future, patients who are at increased risk of poor outcomes may be enrolled in a pre-habilitation program targeted at improving muscle mass. This study may provide data to inform future studies relating to muscle mass preservation which could also be applicable to wider patient populations, both surgical and non- surgical.
Dr Catherine Ashes, St Vincent’s Hospital, NSW.
The project was awarded $A15, 631 through the ANZCA research grants program for 2022.