Progressive Additive Benefits of Prehabilitation and Subsequent Bariatric Surgery on Cardiac Autonomic Regulation as Assessed by Means of a Simple Unitary Composite Index: Preliminary Data from an Observational Study

Obesity is associated with an increased risk of several chronic comorbidities, which may
also be determined by dysfunctional autonomic nervous system (ANS). The influence of bariatric
surgery (BS) on ANS balance was explored in previous studies, but with high heterogeneity in both
the assessment timing and methods employed. In the present observational study, we applied a
clinical protocol which considers two subsequent phases. Twenty-nine non-diabetic obese subjects
were studied at baseline (T0), after one month of lifestyle modification (prehabilitation) (phase 1-T1),
and after eight months following BS (phase 2-T2). ANS regulation was assessed across the three study
epochs by means of ANSI, a single composite percent-ranked proxy of autonomic balance, being free
of gender and age bias, economical and simple to apply in a clinical setting. The aim of the present
study was to investigate the effects of the clinical protocol based on prehabilitation and subsequent
BS on the ANS regulation by means of ANSI. Potential intertwined correlations with metabolic
parameters were also investigated. Notably, we observed a progressive improvement in ANS control,
even by employing ANSI. Moreover, the reduction in the markers of sympathetic overactivity was
found to significantly correlate with the amelioration in some metabolic parameters (fasting glucose,
insulin levels, and waist circumference), as well as in stress and tiredness perception. In conclusion,
this study provides convincing evidence that a unitary proxy of cardiac autonomic regulation (CAR)
may reflect the progressive improvement in autonomic regulation following behavioral and surgical
interventions in obese patients. Intriguingly, this might contribute to reducing cardiovascular and
metabolic risk.