Rw. Redline et A. Pappin, FETAL THROMBOTIC VASCULOPATHY - THE CLINICAL-SIGNIFICANCE OF EXTENSIVE AVASCULAR-VILLI, Human pathology, 26(1), 1995, pp. 80-85
Thrombosis of large fetal vessels in the placenta leads to regions of
downstream avascular villi (AV). Avascular villi have been associated
with adverse outcomes in anecdotal reports, but no controlled study of
their significance has been done. We prospectively gathered cases of
extensive AV (n=29) occurring over a 2-year period at the Institute of
Pathology at Case Western Reserve University and compared obstetric h
istory, coexistent placental pathology, and neonatal outcome to gestat
ional age-matched controls in a case control study. The diagnosis of e
xtensive AV required one or more of the following characteristics: 2.5
% or more of total villous parenchyma affected, fod in multiple sectio
ns, or a single lesion measuring 0.25 cm(2) or larger. Women with AV p
lacentas had increased rates of intrauterine growth retardation (IUGR)
, acute and chronic monitoring abnormalities, oligohydramnios, and mat
ernal coagulation disorders. Placentas with AV were more likely to hav
e coexistent chronic villitis, membrane hemosiderin, meconium in all t
hree membrane layers, and villous chorangiosis. Finally, among the sub
group of neonates older than 34 weeks gestation without congenital mal
formations or coexistent placental pathology (n=18), we identified sig
nificant abnormalities, including major thrombotic events (n=5), neona
tal death (n=2), umbilical artery pH less than 7.10 (n=4), platelet co
unt less than 150,000 (n=4), increased nucleated red blood cell (NRBC)
counts (n=7), and transient hyploglycemia (n=4). Placental features c
orrelating with clinical abnormalities included percentage of greater
than 30% AV, recent platelet and fibrin aggregates, and multifocal dis
ease involving more than one histological section. HUM PATHOL 26:80-85
. Copyright (C) 1995 by W.B. Saunders Company