Malformations attributed to the process of vascular disruption.

BACKGROUND

Several malformations have been attributed to the process of vascular disruption. The central hypothesis for this etiology is that blood flow to a structure has been altered after that structure had formed normally. The decreased blood flow leads to hypoxia, endothelial cell damage, hemorrhage, tissue loss, and repair. After recovery, some structures are normal and others show either tissue loss or structural abnormalities, such as syndactyly and constriction rings.

METHODS

The phenotypic features of the 7,020 infants with one or more malformations, who were born to women who had always planned to deliver at Brigham and Women's Hospital (BWH) between, 1972 and 2012, that is, maternal nontransfers, were reviewed. The phenotypes associated with vascular disruption, such as the amniotic band syndrome and terminal transverse limb defects (TTLD), were identified.

RESULTS

One hundred and five fetuses and infants had malformations attributed to the process of vascular disruption. Some specific causes of the amniotic band limb deformity were identified. TTLD with associated small digit-like nubbins occurred at three levels: proximal forearm, wrist, and metacarpal-phalangeal joint. Other causes included severe hemoglobinopathies and exposures to misoprostol and to prenatal procedures.

CONCLUSIONS

Malformations attributed to the process of vascular disruption were a distinctive entity, among the recognized etiologies. The timing of the causative event in the first trimester was established for infants with exposures to either the prostaglandin misoprostol or the prenatal diagnosis procedure chorionic villus sampling. One challenge is to identify the developmental steps in vascular disruption when no causative exposure can be identified.