Effect of prolonged targeted temperature management on left ventricular myocardial function after out-of-hospital cardiac arrest - A randomised, controlled trial

Abstract

Aim: To evaluate post-cardiac arrest myocardial dysfunction during prolonged targeted temperature management (TTM) compared with standard TTM in comatose out-of-hospital cardiac arrest (OHCA) survivors.

Methods: A randomised, controlled trial comparing myocardial function after TTM at 33 ±1°C for 48h compared with 24h. A total of 105 OHCA patients were computer-randomised to 24h (n=50) or 48h (n=55) of TTM. Transthoracic echocardiography was performed after 24h, 48h and 72h. Echocardiographic parameters were evaluated by an investigator who was blinded to randomisation. The primary endpoint was peak systolic mitral annular velocity (Ś) measured as the difference in the period from 24h to 72h. The model was adjusted for age, primary rhythm and heart rate. The secondary outcomes were global peak longitudinal strain, left ventricular ejection fraction (LVEF), tricuspid annular plane systolic excursion (TAPSE) and the diastolic measures e' and E/e'.

Results: The mean difference of S' was significantly increased in the 48h group compared with the 24h group: -1.14cm/s (-1.83; -0.45), p=0.001. This difference was consistent after adjusting the data (p=0.008). However, there were no significant changes between the study groups with respect to the adjusted secondary outcomes of global peak longitudinal strain (p=0.07), LVEF (p=0.31), TAPSE (p=0.91), e' (p=0.26) and E/e' (p=0.18).

Conclusion: Prolonged TTM at 33°C of 48h compared with 24h in comatose OHCA survivors may improve the recovery of post-cardiac arrest left myocardial dysfunction demonstrated by the echocardiographic outcome, S'. ClinicalTrials.gov identifier: NCT02066753.

Keywords: Body temperature regulation; Cardiac arrest; Echocardiography; Heart arrest; Out-of-hospital cardiac arrest; Post resuscitation care; Targeted temperature management; Temperature; Therapeutic hypothermia.