Management of Kell isoimmunization--evaluation of a Doppler-guided approach.
OBJECTIVE
To assess the role of peak systolic velocity in the middle cerebral artery (MCA-PSV) in the management of pregnancies complicated by Kell isoimmunization.


METHODS
Sixteen fetuses were monitored by conventional protocol (Group 1) and eight fetuses by an MCA-PSV-guided protocol (Group 2). The conventional protocol included a weekly ultrasound evaluation and measurement of maternal anti-Kell titers every 4-6 weeks. In Group 2 Doppler assessment of the MCA-PSV was performed at intervals of 4 to 7 days and MCA-PSV>1.5 multiples of the median (MoM) was considered as an indication for fetal blood sampling (FBS).


RESULTS
No parameter emerged as a reliable predictor of isoimmunization severity in Group 1. In Group 2, no FBS was necessary in one case since the MCA-PSV values obtained during the follow-up were <1.29 MoM. In two cases the first FBS was already indicated after 1 week of follow-up, but five other fetuses were followed for 3-9 weeks before FBS was indicated. All fetuses with MCA-PSV>1.5 MoM prior to intrauterine transfusion (IUT) had severe fetal anemia on FBS. In fetuses with severe anemia on the first FBS, the MCA-PSV values 7 days before the first FBS were <1.29 MoM (four cases), between 1.29 and 1.5 MoM (two cases) and >1.55 MoM (one case).


CONCLUSIONS
In the management of Kell isoimmunization invasive procedures may be avoided by implementing MCA-PSV measurements. Delineation of appropriate intervals between reassessments, the reliability of MCA-PSV following repeated IUTs, and cut-off values for FBS await further study.
Rimon
E
E
Department of Obstetrics and Gynecology, Chaim Sheba Medical Center and the Sackler Faculty of Medicine, Tel-Aviv University, Tel-Hashomer, Israel. rimoneli@yahoo.com
Peltz
R
R
Gamzu
R
R
Yagel
S
S
Feldman
B
B
Chayen
B
B
Achiron
R
R
Lipitz
S
S
D000328:Adult; D000751:Anemia, Neonatal / Q000000981:diagnostic imaging* / Q000196:embryology; D001787:Blood Group Incompatibility / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007626:Kell Blood-Group System / Q000032:analysis / Q000097:blood*; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011247:Pregnancy; D018608:Ultrasonography, Doppler / Q000295:instrumentation / Q000379:methods*
D007626:Kell Blood-Group System