Echocardiographic parameters during prolonged targeted temperature Management in out-of-hospital Cardiac Arrest Survivors to predict neurological outcome - a post-hoc analysis of the TTH48 trial

Abstract

Background: Transthoracic echocardiographic (TTE) indices of myocardial function among survivors of out-of-hospital cardiac arrest (OHCA) have been related to neurological outcome; however, results are inconsistent. We hypothesized that changes in average peak systolic mitral annular velocity (s') from 24 h (h) to 72 h following start of targeted temperature management (TTM) predict six-month neurological outcome in comatose OHCA survivors.

Methods: We investigated the association between peak systolic velocity of the mitral plane (s') and six-month neurological outcome in a population of 99 patients from a randomised controlled trial comparing TTM at 33 ± 1 °C for 24 h (h) (n = 47) vs. 48 h (n = 52) following OHCA (TTH48-trial). TTE was conducted at 24 h, 48 h, and 72 h after reaching target temperature. The primary outcome was 180 days neurological outcome assessed by Cerebral Performance Category score (CPC180) and the primary TTE outcome measure was s'. Secondary outcome measures were left ventricular ejection fraction (LVEF), global longitudinal strain (GLS), e', E/e' and tricuspid annular plane systolic excursion (TAPSE).

Results: Across all three scan time points s' was not associated with neurological outcome (ORs: 24 h: 1.0 (95%CI: 0.7-1.4, p = 0.98), 48 h: 1.13 (95%CI: 0.9-1.4, p = 0.34), 72 h: 1.04 (95%CI: 0.8-1.4, p = 0.76)). LVEF, GLS, E/e', and TAPSE recorded on serial TTEs following OHCA were neither associated with nor did they predict CPC180. Estimated median e' at 48 h following TTM was 5.74 cm/s (95%CI: 5.27-6.22) in patients with good outcome (CPC180 1-2) vs. 4.95 cm/s (95%CI: 4.37-5.54) in patients with poor outcome (CPC180 3-5) (p = 0.04).

Conclusions: s' assessed on serial TTEs in comatose survivors of OHCA treated with TTM was not associated with CPC180. Our findings suggest that serial TTEs in the early post-resuscitation phase during TTM do not aid the prognostication of neurological outcome following OHCA.

Trial registration: NCT02066753 . Registered 14 February 2014 - Retrospectively registered.

Keywords: Cardiac arrest; Echocardiography; Out-of-hospital cardiac arrest; Prognostication; Targeted temperature management.

Fig. 1

Consort diagram. Technical problems indicate problems with poor image quality where outcomes were not assessable

Fig. 2

Estimated medians of echocardiographic outcomes. Echocardiography outcomes across all scan time points in the good outcome group and the poor outcome group, respectively. X-axes refer to scan time points. When testing for parallel curves, no graphs showed significantly different curves. Significant differences at time points are indicated below. Abbreviations: CPC180: cerebral performance category at 180 days, EF: ejection fraction, GLS: global longitudinal strain, h: hours, IVC: inferior vena cava variability, mm: millimetre, TAPSE: tricuspid annular plane systolic excursion. *: p = 0.044, #: p = 0.036