LV hypoplasia and dysfunction in CDH
Physiology
CDH newborns often present with signs of PH and respiratory failure
Increasing reports of LV hypoplasia in CDH: autopsy, fetal and MRI studies
Mechanical compression of heart during fetal growth
Primary mesenchymal defect resulting into left-sided anomalies
Abnormal streaming of fetal blood flow preferentially filling the RV
Underfilling secondary to decreased pre-load
Pancaking by the pressure overloaded right ventricle
Fetus with CDH: Cardiac ventricular disproportion associated with post-natal mortality (Crawford DR et al. Br J Obstet Gynaecol. 1989 - Jun;96(6):705-10.; Sharland GK et al. Am J Obstet Gynecol. 1992 Jan;166(1 Pt 1):9-13.)
Newborns with CDH: Report of reduction in indexed LV mass (Schwarts SM et al. J Pediatr. 1994 Sep;125(3):447-51; Karamanoukian HL et al, J Pediatr Surg. 1995 Jul;30(7):925-8)
ECMO: lower indexed LV mass than those without ECMO
Confirmed in neonatal lamb model
Adults with CDH: Persistent abnormal cardiac function and decreased LV stroke volume by MRI (Abolmaali N et al. Eur Radiol 20:1580–1589)
Case 1
38+5 weeks, male
Prenatal diagnosis of L-CDH
Liver, spleen in the chest
AC-PC: 45 x 25/5
Initially 50% FiO2 with pre-post differences (95% and 75%)
Started by iNO by clinical team
57/41 BP by UAL
Called for evaluation by ECHO
Found to have: Moderate-severe LV dysfunction; Lactate adequate, urine output 2 mL/kg/hr; iNO wean; Decision to initiate Milrinone 0.5 mcg/kg/min considering the normal BP and urine output; Hydrocortisone added at 1mg/kg IV q8hr;
ECHO repeated DOL3: mild LV dysfunction to normal LV function, PDA small bidirectional (mostly Left to right)
Initial ECHO:
Mild to moderate mitral regurgitation in the apical 4 chamber view
Some degree of LV dysfunction in A4C
Moderate dysfunction in the A2C
Depressed Ejection fraction by Speckle Tracking echocardiography
Abnormal strain (deformation) using speckle tracking echocardiography for the LV.
CDH repaired at DOL4. TnECHO repeated post-OR DOL6:
RV dilation and bowing of the septum in systole towards the left ventricle indicating supra-systemic pulmonary pressure.
RV dilation by 3D echocardiography
Restrictive ductus that is bidirectional. Right to left in systole with estimated PA to Ao gradient of 33 mmHg
TR indicating supra-systemic pulmonary arterial pressure 94 mmHg of RV-RA gradient, for sBP at the time of the ECHO at around 60 mmHg.
Following the introduction of iNO during the ECHO, the RV decompressed, the PDA became predominantly left to right and the TR decreased to 50 mmHg.
Patient with echocardiographic and clinical response to iNO
Mixed picture: Initial biventricular dysfunction: initially LV dysfunction and eventually pulmonary reactive vascular disease with RV dysfunction
Last ECHO: TR at 37, RV function and LV function normal by various metrics.
Case 2
Lt. sided CDH.
Born at 38 wks.
Post-natal, MAP 15, FiO2 80% with PaO2 35 (OI: 35)
Pre-ductal saturation 89, post-ductal of 56%
mBP (via UAL): 32
Initial Echo
PFO is bidirectional but mostly left to right
Septal flattening/bowing.
Restrictive ductus - bidirectional
TR with RV-RA gradient of about 100 mmHg
Bidirectional PDA with right to left gradient in systole of 30 mmHg.
Bidirectional PDA with R-L gradient in systole of 30 mmHg.
PFO bidirectional, mostly left to right.
TR 102 mmHg with SBP at 59 mmHg,
Suprasystemic PA pressure.
Mild RA and RV dilatation.
RV dysfunction by TAPSE - 5.6 mm.
Estimated LV end diastolic volume Z-score -3.5 by 3D
Predominant picture: small LV/dysfunction with altered output + PH
Started on PGE 0.01 mcg/kg/min + Milrinone; given restrictive ductus, adequate sBP and urine output (Word of acution: milrinone can lead to severe distributive shock with vasodilation if already hypotensive and oliguria/anuria since renally excreted)
After PGE and Milrinone - ECHO
PDA is now large and bidirectional - not restrictive, with minimal gradient right to left in systole). Allows to pop-off the RV and maintain LV output.
Adequate RV and LV function. The RV is less dilated.
The PFO is now only left to right.
Septum is round at peak of systole and RV is decompressed.
