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

Initial ECHO:

Abnormal strain (deformation) using speckle tracking echocardiography for the LV. 

CDH repaired at DOL4. TnECHO repeated post-OR DOL6:

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. 

Case 2

Initial Echo

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.