BACKGROUND: Possible sarcopenia, aortic valve stenosis, and malnutrition are important issues that afflict older adults. OBJECTIVE: The aims of this study were to compare the differences in nutritional status and family support in older adults with possible sarcopenia and those without sarcopenia after undergoing transcatheter aortic valve implantation (TAVI) and to identify the predictors of malnutrition and demonstrate changes in heart function over time after undergoing TAVI. METHODS: A case-control design was conducted. Possible sarcopenia was identified by measuring calf circumference, grip strength, and gait speed. The Mini Nutritional Assessment-Short Form and numerical family support rating scale were used to collect data. Left ventricular ejection fraction and New York Heart Association (NYHA) functional class were assessed at 5 time points to evaluate heart function. RESULTS: Eighty-one participants were categorized into those without sarcopenia (34) and those with possible sarcopenia (47). Logistic linear regression showed albumin and possible sarcopenia to be predictors of malnutrition (odds ratio, 5.5; 95% confidence interval, 1.02-30.19). Family support was associated with nutrition status (P = .019). For patient heart function, the results of NYHA functional class and left ventricular ejection fraction improved over time after TAVI. The improvement in NYHA functional class at T2 was significantly different between the 2 groups compared with that at T0. CONCLUSIONS: The nutrition level was higher among participants without sarcopenia than those with possible sarcopenia. Approximately 90% of the participants indicated that they had high family support. Demographic factors and albumin levels could be used to evaluate risk of malnutrition. Patients without possible sarcopenia showed greater improvement in NYHA class.