(1136) Redefining maternal vascular malperfusion (MVM) placental disease by circulating placental growth factor (PlGF) level

Maternal Vascular Malperfusion (MVM) is the most common placental diagnosis associated with preeclampsia, fetal growth restriction (FGR) and stillbirth.  However, 50% of placentas meeting diagnostic criteria for MVM result in healthy term pregnancies. Our objective was to determine which features currently used to establish a pathologic diagnosis (MVM) are most strongly correlated with low circulating placental growth factor (PlGF) as a marker of clinically meaningful placental dysfunction, as well as investigate patterns of association between pathologic features.  

Study Design:

We conducted a single-centre, retrospective cohort study in women with singleton pregnancies where decreased PlGF ( < 100pg/mL) was measured between 20 and 36 weeks gestation, with placental evaluation following delivery. Placental characteristics were systematically analyzed according to the Amsterdam Consensus for MVM. Findings were compared between MVM and non-MVM groups using a Chi-Square test. Cluster analysis was then performed using K-Modes unsupervised clustering algorithm.

Results:

Between March 2017 and December 2019, 337 pregnancies met inclusion criteria, of which 242 (71.8%) met current diagnostic criteria of MVM disease. Features significantly associated with MVM diagnosis were placental weight < 10%ile, eccentric cord insertion, placental infarction, distal villous hypoplasia, accelerated villous maturation, and decidual vasculopathy (p < 0.01) (table 1).  The features most specific to MVM pathology were distal villous hypoplasia (specificity 99%, PPV 99%,), and decidual vasculopathy (specificity 95%, PPV 96%).  Cluster analysis identified four phenotypic clusters (figure 1).

Conclusion:

These findings highlight the features which define maternal vascular malperfusion in the context of low circulating PlGF, as well as the heterogeneity of MVM placental disease under the current diagnostic criteria. This knowledge may be used to establish a hierarchy of specific gross and histologic observations to define MVM disease with greater diagnostic precision for meaningful adverse clinical outcomes.