Hand Grip Strength at 4.5 Years of Age After Complex Cardiac Surgery in Early Infancy

Hand grip strength (HGS) is a validated measure of muscle function. We aimed to determine HGS and its predictors in young children after complex cardiac surgery in early infancy. A prospective inception-cohort of children who had complex cardiac surgery in early infancy between 2010-2019 had HGS measured using the Martin Vigorimeter at age 4.5 years. Predictor variables (demographics, severity-of-illness perioperatively and at age 4-5 years, and outcomes at 4-5 years of age) association with HGS were determined using univariate and two multiple linear regression models (considering all variables, and excluding distal variables). Of 390 survivors, 165 (42%) completed and 162 (42%) did not complete HGS assessment, and 63 (16%) were lost to follow-up or pending. Children who did not complete HGS had significantly higher illness severity and adverse outcome variables versus children who had HGS assessed. Stronger hand Z-scores for HGS were mean 1.16 (SD 1.72). In model 1, lower HGS z-score was statistically associated with small for gestational age, while higher HGS z-score was statistically associated with full-scale intelligence quotient and height z-score. In model 2, highest lactate after surgery was statistically associated with lower HGS z-score (Effect Size -0.11 (95% CI -0.21, -0.02), p=0.022). HGS measurement was feasible in 42% of survivors, limiting its application at the young age of 4.5 years after having had complex cardiac surgery in infancy. Risk factors including small for gestational age and highest lactate after surgery may be modifiable.