Variations in phase angle and handgrip strength in patients undergoing cardiac surgery: Prospective cohort study

Bioimpedance phase angle (PA) is a measure of cell membrane integrity, whereas handgrip strength (HGS) is an evaluation of functional capacity. Although both are related to the prognosis of patients undergoing cardiac surgery, their changes over time are less known. This study followed variations in PA and HGS for 1 year in these patients, determining associations with clinical outcomes.

This prospective cohort study included 272 cardiac surgery patients. PA and HGS were measured at six predetermined times. The evaluated outcomes were surgery type; bleeding; time of surgery, cardiopulmonary bypass, aortic cross-clamp, and mechanical ventilation; postoperative (PO) length of stay (LOS) in the intensive care unit (ICU) and hospital; and infections, hospital readmission, reoperation, and mortality.

There were reductions in PA and HGS values after surgery, with total recovery beginning at 6 months for PA and 3 months for HGS. In the PA area under the curve (AUC), age, combined surgery, and sex (β = -9.66, P < 0.001; β = -252.85, P = 0.005; β = -216.56, P < 0.001, respectively) were predictors for PA-AUC reduction. Stratified by sex, age (β = -93.54, P < 0.001) and PO LOS (β = -46.91, P = 0.003) were predictors for HGS-AUC reduction in women, but only age was a predictor in men (β = -77.02, P = 0.010). PA and HGS had an effect in hospital LOS and ICU LOS.

Age, combined surgery, and female sex were predictors of reduced PA-AUC, whereas reduced HGS-AUC was predicted by age in both sexes and PO hospital LOS in women, which suggests that these factors could interfere in prognosis.