Objectives: Acute myocardial infarction (AMI) is myocardial necrosis resulting from myocardial ischemia, and its risk factors are usually a combination of the consumption of tobacco, inadequate diet, obesity, and a sedentary lifestyle, in addition to preexisting comorbidities. These risk factors may compromise cellular integrity, affecting physiologic and nutritional components. The phase angle (PhA) has been measured by bioelectrical impedance analysis (BIA) to identify the quality of the cell membrane and the distribution of body fluids. The aim of this study was to verify if the standardized PhA (SPhA) is a predictor of short- and long-term adverse cardiovascular events in patients after AMI.
Methods: This was a prospective cohort study including hospitalized adult patients with a diagnosis of AMI. Demographic, clinical, and nutritional data were collected. The PhA was calculated through the measuring of the resistance (R) and reactance (Xc) from BIA, and it was adjusted based on reference values for sex and age, presenting, therefore, the SPhA. Low SPhA was defined as that <10th percentile of distribution. Hospital length of stay (LOS) and major adverse cardiac events (MACE), such as new hospital admission for unstable angina, new MI, and cardiovascular mortality, were observed. The sample comprised 153 patients, with a mean age of 61.2 ± 12.6 y, with 57.5% being older adults.
Results: Fifteen patients with low SPhA (values <-3.10) had a longer LOS compared with those with normal SPhA (median 14 versus 8 d, P = 0.007), and shorter time for the occurrence of death (320 versus 354 d, P = 0.024). In the multivariate analysis, an association was observed between SPhA and longer LOS (hazard ratio, 9.25; P = 0.005), but not with mortality and MACE (P > 0.05 for all).
Conclusion: SPhA was a predictor of longer LOS, but not of long-term adverse cardiac events in patients following AMI.
Keywords: Bioelectrical impedance analysis; Coronary arterial disease; Hospital readmission; Mortality; Phase angle; Prognostic factors.
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