Retrospective study of left and right ventricular strain mechanics among neonates undergoing therapeutic hypothermia for neonatal encephalopathy

Abstract

Purpose

Early diagnosis of impaired myocardial function and timely therapeutic hypothermia is vital among patients with Neonatal Encephalopathy (NE). Traditional markers of myocardial function (Left Ventricular Ejection Fraction (LV EF) & LV Fractional Shortening (LV FS) can be variably reduced. Speckle tracking echocardiography (STE) is a more sensitive marker for impairment but remains inadequately studied in this patient population.

Methods

A retrospective study of neonates who underwent therapeutic hypothermia (TH) for NE from 2009 to2020 were matched 1:1 with normal neonates with normal echocardiograms performed for indications other than NE. Matching was based on gestational age, birth weight, days of age, and sex. Left ventricular 4 Chamber (4Ch) strain, right ventricular 4 Chamber (RV 4Ch), and RV free wall strain (RV FWS) were measured offline using vendor independent strain software (TomTec, GMBH, Munich, Germany).

Results

Ninety pairs of NE patients and controls were studied. Compared to controls, RV 4Ch strain (−17.3 % vs. -19.6 %), RV FWS (−18.8 % vs. -21.9 %), and RV fractional area change (FAC) (35 % vs. 37 %) were lower in NE cases (all p < 0.001), while differences in LV 4Ch strain, LV EF, and LV FS did not reach statistical significance. Moderate/severe NE (72 %) was associated with lower LV 4Ch strain compared to mild NE (−22.2 %/−19.3 % vs. -25.4 %, p = 0.004). RV 4Ch strain (−14.9 % vs. -18.8 %, p = 0.020) and RV FAC (27 % vs. 36 %, p = 0.006) were lower in severe NE compared to mild NE. Lower LV 4Ch was associated with need for chest compressions (−18.5 % vs. -23.3 %), epinephrine at delivery (−19.3 % vs. -23.4 %), and decreased survival to discharge (−15.9 % vs. -22.7 %).

Conclusions

RV and LV strain mechanics are impaired in NE patients. Lower RV Strain and LV 4Ch strain were associated with need for increased medical support and decreased survival to discharge.