# Bioreactance assessment of cardiac output lacks reliability for the follow-up of patients with pulmonary hypertension

## TL;DR

This study finds that bioreactance is not reliable for tracking cardiac output in pulmonary hypertension patients compared to invasive methods.

## Contribution

The study evaluates bioreactance's reliability for monitoring cardiac output in pulmonary hypertension patients, showing poor agreement with thermodilution.

## Key findings

- Bioreactance CO measurements were significantly lower than thermodilution measurements.
- The correlation between bioreactance and thermodilution CO was moderate (Spearman r = 0.51).
- Bioreactance failed to reliably detect CO changes of more than 15% (AUC = 0.54).

## Abstract

Cardiac output (CO) is one of the primary prognostic factors evaluated during the follow-up of patients treated for pulmonary hypertension (PH). It is recommended that it be measured using the thermodilution technique during right heart catheterization. The difficulty to perform iterative invasive measurements on the same individual led us to consider a non-invasive option. The aims of the present study were to assess the agreement between CO values obtained using bioreactance (Starling™ SV) and thermodilution, and to evaluate the ability of the bioreactance monitor to detect patients whose CO decreased by more than 15% during follow-up and, accordingly, its usefulness for patient monitoring. A prospective cohort study evaluating the performance of the Starling™ SV monitor was conducted in patients with clinically stable PH. Sixty patients referred for hemodynamic assessment were included. CO was measured using both the thermodilution technique and bioreactance during two follow-up visits. A total of 60 PH patients were included. All datasets were available at the baseline visit (V0) and 50 of them were usable during the follow-up visit (V1). Median [IQR] CO was 4.20 l/min [3.60–4.70] when assessed by bioreactance, and 5.30 l/min [4.57–6.20] by thermodilution (p<0.001). The Spearman correlation coefficient was 0.51 [0.36–0.64], and the average deviation on Bland-Altman plot was -1.25 l/min (95% CI [-1.48–1.01], p<0.001). The ability of the monitor to detect a variation in CO of more than 15% between two follow-up measurements, when such variation existed using thermodilution, was insufficient for clinical practice (AUC = 0.54, 95% CI [0.33–0.75]).