# Poor Sympathetic Compensation During Active Standing Increases the Risk of Morbidity–Mortality in the Post-Surgery of Patients with Severe Calcific Aortic Stenosis

## TL;DR

Patients with severe aortic valve disease who poorly adjust their heart rate when standing are at higher risk of complications or death after surgery.

## Contribution

Identified poor sympathetic compensation during standing as a novel predictor of post-surgery complications in aortic stenosis patients.

## Key findings

- Poor sympathetic compensation during active standing was independently associated with complications or death after surgery.
- Patients with complications had smaller changes in heart rate variability indices when standing.
- Greater left ventricular mass was also linked to increased risk of adverse outcomes.

## Abstract

Patients with severe calcific aortic valve stenosis have chronic sympathetic hyperactivity and a diminished increase in sympathetic activation when they change from supine position (resting) to active standing. In this work, we tested whether the change in heart rate variability indices, as a measure of cardiac autonomic modulation, was associated with complications or mortality after the patients had surgery to replace the aortic valve. We found that those who had complications or mortality after the surgery had a smaller change in their heart rate variability indices when standing, consistent with smaller sympathetic activation compared to those without complications or mortality. We discuss the physiological alterations that may lead to poor compensation of the sympathetic nervous system when the body faces the physiological challenge of standing up before surgery and how this could be tested in future studies as a potential predictor of complications or death after surgery.

(1) Background: Although all severe calcific aortic stenosis (SCAS) patients have decreased sympathetic compensation to active standing, it has not been studied in patients who underwent aortic valve replacement (AVR). The objective was to assess the association of the heart rate variability (HRV) response to an active orthostatic challenge before AVR with the risk of complications or death during the AVR postoperative period in patients with SCAS. (2) Methods: This observational study included 49 patients. The cardiac autonomic activity was assessed by HRV analysis during supine position and active standing (five minutes each). (3) Results: Twenty-four patients (48.9%) who presented outcomes (complication or death) had a greater left ventricular (LV) mass and a smaller magnitude of change during active standing in both the mean cardiac period and sympathetic predominance. Poor sympathetic compensation to active standing and LV mass were independently associated with the outcome odds ratio (OR) = 4.8 [(1.06, 21.8), p < 0.041] and 1.03 [(1.007, 1.062), p < 0.013], respectively. (4) Conclusions: In SCAS patients, poor sympathetic compensation in the face of orthostatic challenge and greater LV mass are associated with complications or death after AVR surgery. This approach offers an opportunity to find new criteria to reduce the surgical risk of these patients.