O1020: Assessment of Left and Right Ventricular Strain Mechanics Among Neonates Undergoing Therapeutic Hypothermia for Hypoxic Ischemic Encephalopathy

Background: Early diagnosis of impaired myocardial function and timely therapeutic hypothermia is vital among neonates with peripartum asphyxia and moderate/severe hypoxic ischemic encephalopathy (HIE). Traditional markers of myocardial function (Left Ventricular Ejection Fraction, LVEF; LV Shortening Fraction, LV FS) can be variably reduced. Speckle tracking echocardiography is a more sensitive marker for impairment, but remains inadequately studied, particularly in the neonatal population.

Methods: Neonates who underwent therapeutic hypothermia for HIE from 2009-2020 were matched 1:1 with normal neonates delivered during the same period with echocardiograms done for indications other than HIE (Figure 1). Patients (pts) were matched based on gestational age, birth weight, days of life, and gender. LV global longitudinal strain (LV GLS), Right Ventricular GLS (RV GLS), and RV Free Wall Strain (RV FWS) were measured offline using TomTec software.

Results: 90 HIE patients and 90 controls were reviewed. 72.2% of pts had moderate/severe HIE. RV GLS (-17.3 vs. -19.6, p< 0.001), RV FWS (-18.8 vs. -21.9, p < 0.001), and most RV wall segments demonstrated significantly lower strain among HIE cases. Overall, LV GLS, LV EF, and LV FS were not significantly different between HIE and control groups (Table 1). Among HIE pts, lower LV GLS was associated with death before discharge, need for chest compressions, epinephrine during initial resuscitation, and inotrope use during admission (all p values < 0.05; Table 2). Lower LV GLS correlated with a lower LV EF (Spearman ρ = -0.29, p = 0.005), but not with LV FS (p = 0.20). Compared to mild and moderate HIE patients, LV GLS was significantly lower in severe HIE patients (-25.4 vs -23.0 vs -19.3, p = 0.002; Table 2). RV GLS was significantly lower among severe versus mild HIE patients (-14.9 vs. -18.8, p = 0.020; Table 3).

Conclusion: Both right and left ventricular strain mechanics are impaired in pts with HIE, especially in severe HIE. Compared to controls, HIE tended to have a lower RV GLS, FWS, and segmental strain in most RV segments. Within cases, severity of HIE tended to correlate with a lower LV GLS, with the latter further associated with need of medical resuscitation/support and decreased survival to discharge, highlighting it as a potential important early prognostic marker.