Lung tissue blood perfusion changes induced by in utero tracheal occlusion in a rabbit model of congenital diaphragmatic hernia.
OBJECTIVE
To analyze the impact of in utero tracheal occlusion (TO) on lung tissue blood perfusion, as measured by fractional moving blood volume (FMBV) and conventional spectral Doppler, in a rabbit model of congenital diaphragmatic hernia (CDH).


METHODS
In 50 fetal rabbits, a left CDH was surgically created at 23 days of gestational age (GA). At 28 days of GA, the surviving CDH fetuses were randomly assigned to undergo either TO (CDH+TO group) or a sham operation (CDH group). Twenty littermates, which were not operated on, served as internal normal controls. At 30 days of GA, lung perfusion estimated by FMBV and spectral Doppler of the proximal intrapulmonary artery were evaluated in the right lung during cesarean section. Doppler waveform analysis included the pulsatility index (PI), peak early diastolic reverse flow and peak systolic velocity.


RESULTS
Eleven CDH fetuses, 9 CDH+TO and 20 controls were suitable for the study. CDH fetuses showed a significantly higher PI [8.0 (SD 1.8) vs. 5.22 (SD 1.1), p < 0.001] and lower FMBV [13.5% (SD 4.6) vs. 23.0% (SD 2.1), p < 0.001] than the controls. In contrast, CDH+TO fetuses had a significantly lower PI [5.8 (SD 2.3) vs. 8.0 (SD 1.8), p = 0.015] and higher FMBV [27.6% (SD 7.1) vs. 13.5% (SD 4.6), p < 0.001] than CDH fetuses, with values similar to the controls. Peak early diastolic reverse flow and peak systolic velocity showed nonsignificant differences among the study groups. The lung to body weight ratio at necropsy correlated positively with lung FMBV (r = 0.60, p < 0.001) and negatively with the pulmonary artery PI (r = -0.48, p < 0.01).


CONCLUSIONS
Tracheal occlusion is consistently associated with increased lung tissue perfusion and decreased intrapulmonary impedance in a rabbit model of CDH.
Cruz-Martinez
Rogelio
R
Fetal and Perinatal Medicine Research Group, Department of Maternal-Fetal Medicine, Hospital Clinic-IDIBAPS, University of Barcelona and Centre for Biomedical Research on Rare Diseases (CIBER-ER), Barcelona, Spain. jcruz1@clinic.ub.es
Moreno-Alvarez
Oscar
O
Prat
Jordi
J
Krauel
Lucas
L
Tarrado
Xavier
X
Castañón
Montserrat
M
Hernandez-Andrade
Edgar
E
Albert
Asteria
A
Gratacos
Eduard
E
D000818:Animals; D001835:Body Weight; D005260:Female; D005315:Fetal Diseases / Q000503:physiopathology / Q000601:surgery; D005332:Fetoscopy / Q000379:methods; D005865:Gestational Age; D006439:Hemodynamics; D006548:Hernia, Diaphragmatic / Q000503:physiopathology / Q000601:surgery*; D065630:Hernias, Diaphragmatic, Congenital; D008026:Ligation; D008168:Lung / Q000098:blood supply* / Q000196:embryology / Q000473:pathology; D009929:Organ Size; D011247:Pregnancy; D011652:Pulmonary Circulation; D011817:Rabbits; D011897:Random Allocation; D014132:Trachea / Q000196:embryology / Q000601:surgery*; D018608:Ultrasonography, Doppler / Q000379:methods