Perinatal- and procedure-related outcomes following radiofrequency ablation in monochorionic pregnancy.

OBJECTIVE: We sought to assess the efficacy, complication rates, and outcomes for complex monochorionic pregnancies undergoing selective fetal reduction using radiofrequency ablation (RFA). STUDY DESIGN: In this prospective observational study, 100 consecutive cases of selective fetal reduction using RFA were analyzed. All cases were managed at the Centre for Fetal Care at Queen Charlotte's and Chelsea Hospital in London. Indications for offering RFA, details of the procedure, and pregnancy outcomes were collected and analyzed. RESULTS: The main indications for RFA were discordant fetal anomaly and twin-twin transfusion syndrome. Overall live birth rate was 78% and the median gestation at delivery was 35.15 weeks. Delivery <32 weeks' gestation occurred in 17.9% of cases. Postprocedure abnormal antenatal magnetic resonance imaging occurred in 3% of cases. There was no statistical difference in outcomes with regard to gestation when the procedure was performed or the indication for the RFA. CONCLUSION: RFA appears to be a reasonable option for selective fetal reduction in complex monochorionic pregnancies with an overall survival rate of 78%.

Ventricular strain changes in monochorionic twins with and without twin-to-twin transfusion syndrome.

OBJECTIVE: The objective of the study was to investigate whether vector velocity imaging (VVI), a non-Doppler speckle tracking ultrasound technology, is feasible in twin pregnancies and can aid management of twin-twin transfusion syndrome (TTTS). STUDY DESIGN: Twenty-seven women pregnant with monochorionic diamniotic twins affected by TTTS and 28 monochorionic pregnancies that did not develop TTTS were included in a prospective case-control study at a fetal medicine center. Fetal echocardiograms were recorded with dummy electrocardiography to retain original frame rates when exported for offline speckle tracking analysis using Syngo-VVI software (Siemens Corp, Munich, Germany). Right and left ventricular (LV) free wall Lagrangian strain was measured from the original coordinates. Within-twin pair ventricular strain differences including relationship to Quintero staging and response to laser therapy for TTTS were analyzed by Wilcoxon signed-rank test. RESULTS: The VVI strain measurements could be analyzed in 182 of 200 TTTS and 96 of 112 non-TTTS control ventricles. Within-pair strain was concordant in non-TTTS controls. Recipient LV strain was reduced at all Quintero stages compared with donors (P < .01). Recipient right ventricular strain was reduced only in stages 3 and 4 (P < .01). Strain improved at a median of 2 weeks following successful laser therapy. Intertwin differences in strain were independent of weight discordance. CONCLUSION: Recipient LV strain is reduced in stages 1 and 2 TTTS. Within-pair strain discordance may distinguish early TTTS from growth discordance and guide timing of and management following treatment.

Impaired recovery of intracellular calcium and force after activation in isolated myometrial and subcutaneous resistance arteries from women with preeclampsia.

OBJECTIVES: Preeclampsia is a major cause of maternal and perinatal morbidity and mortality, but its cause is poorly understood. This study investigated whether there is an abnormality of intracellular calcium ([Ca2=]i) and tension during recovery from activation in isolated resistance arteries in preeclampsia and investigated the underlying mechanisms. METHODS: Subcutaneous and myometrial resistance arteries from preeclamptic, normotensive pregnant and nonpregnant women were mounted on an isometric myograph and loaded with fura-2 to allow simultaneous measurement of force and [Ca2+]i. Arteries were activated by a high-potassium solution or noradrenaline, and the rate of decline in force and [Ca2+]i examined following washout. RESULTS: Basal tone and [Ca2+]i and rise in force and [Ca2+]i induced by high-potassium solution did not differ between groups but the rate of decline after washout was significantly slowed in both subcutaneous and myometrial arteries from preeclamptic women as compared with normotensive pregnant or nonpregnant women. The rate of decline in force after noradrenaline was also slowed in arteries from preeclamptic women. In subcutaneous resistance arteries from nonpregnant women, removal of the endothelium did not affect the rate of decline in force after high-potassium solution. However, inhibition of the plasma membrane Ca ATPase with carboxyeosin mimicked the findings seen in preeclampsia. In contrast, inhibition of the sarcoplasmic endoreticulum Ca ATPase with cyclopiazonic acid had no effect on the rate of decline in force or [Ca2+]i. CONCLUSION: The rate of relaxation and decline in [Ca2+]i in resistance arteries are impaired in preeclampsia. This may be mediated by decreased activity of plasma membrane Ca2+ ATPase and could be a mechanism contributing to elevated peripheral resistance and raised blood pressure in preeclampsia.

The effect of polyhydramnios on cervical length in twins: a controlled intervention study in complicated monochorionic pregnancies.

OBJECTIVE: To test the hypothesis that cervical shortening in polyhydramnios reflects the degree of excess amniotic fluid, and increases with normalisation of amniotic fluid volume. STUDY DESIGN: Prospective cohort study of 40 women with monochorionic twins undergoing interventional procedures between 16-26 weeks. Cervical length was assessed via transvaginal sonography pre-procedure, 1 and 24 hours post-procedure, and results compared between amnioreduction and control procedures. Amniotic fluid index (AFI) was measured pre- and post-procedure. RESULTS: Pre-procedural cervical length correlated with AFI (linear fit = 5.07 -0.04x, R(2) = 0.17, P = 0.03) in patients with polyhydramnios (n = 28). Drainage of 2000 ml fluid (range 700-3500 ml), reduced AFI from 42 cm to 21 cm (P<0.001). Their pre-procedural cervical length did not change at one (mean Delta:-0.1cm, 95%CI, -0.4 to 0.2) or 24 hours (0.2 cm, -0.1 to 0.6) after amnioreduction. There was no change in cervical length at control procedures. CONCLUSION: Cervical shortening in twins with polyhydramnios does not appear to be an acute process; cervical length can be measured before or after therapeutic procedures.

Interstitial laser therapy for fetal reduction in monochorionic multiple pregnancy: loss rate and association with aplasia cutis congenita.

OBJECTIVE: To evaluate experience with interstitial laser therapy for intrafetal vascular ablation in monochorionic (MC) multiple pregnancy. METHODS: MC pregnancies that underwent fetal reduction between 1998 and 2007 by interstitial laser therapy were reviewed. Indications were twin reversed arterial perfusion sequence (TRAP) (n = 10), twin-to-twin transfusion (6), discordant abnormality (7) or growth (1) and high-order multiples (6). RESULTS: Thirty pregnancies treated at 15 weeks (median, range: 11 weeks-20 weeks, 5 days) had no technical failures but four manifested procedure-related amniorrhexis. Four of 38 remaining fetuses suffered intrauterine death (IUFD) within 24 h, giving an early procedure-related fetal loss rate of 10% per pregnancy and 11% per fetus. A further five IUFDs occurred within 2 weeks, giving a maximum procedure-related loss rate of 27% per pregnancy and 24% per fetus. Median gestation at delivery was 37 weeks (18 weeks, 1 day-41 weeks, 3 days) for pregnancies continuing > 2 weeks. Perinatal survival was 26 of 38 (68%) in nonreduced fetuses. Two of 26 neonates (8%) were diagnosed with aplasia cutis congenita (ACC). CONCLUSION: Interstitial laser therapy in complicated MC pregnancies carries significant risks of unintended fetal loss and may be associated with ACC.

Effects of vasoactive agents on intracellular calcium and force in myometrial and subcutaneous resistance arteries isolated from preeclamptic, pregnant, and nonpregnant woman.

OBJECTIVE: Preeclampsia is a common and serious complication of pregnancy, characterized by maternal hypertension and proteinuria, placental insufficiency, and fetal growth restriction. The purpose of this study was to investigate whether intracellular Ca 2+ ([Ca 2+ ] i ) and contractile responses of vascular smooth muscle to vasoactive agents are altered in preeclampsia compared with normal pregnancy and the nonpregnant state. STUDY DESIGN: Subcutaneous and myometrial resistance arteries from women who had preeclampsia, normal pregnancy, and nonpregnant women were obtained at the time of cesarean section or hysterectomy. Arteries were mounted on an isometric myograph and loaded with the Ca 2+ indicator, fura-2AM, to permit simultaneous measurement of force and [Ca 2+ ] i . Reponses to endothelium-dependent relaxants (acetylcholine and substance P) and vasoconstrictors (depolarizing potassium solution, phenylephrine, and angiotensin II) were examined. RESULTS: The fall in [Ca 2+ ] i and relaxation in response to acetylcholine was significantly inhibited in both myometrial and subcutaneous arteries from preeclamptic women compared with arteries from nonpregnant or normal pregnant women. However, responses to substance P did not differ between the 3 groups. There were no significant differences in [Ca 2+ ] i or force responses to high potassium, phenylephrine, or angiotensin II in myometrial and subcutaneous resistance vessels in women with preeclampsia compared with normal pregnant women. However, force, but not [Ca 2+ ] i responses to angiotensin II, in subcutaneous vessels from normal pregnant and preeclamptic women were reduced compared with subcutaneous arteries from nonpregnant women, indicating that pregnancy is associated with a reduction in Ca 2+ sensitization in this tissue. A similar effect was not seen in myometrial arteries. CONCLUSION: Endothelial function is altered in preeclampsia, with loss of effect of acetylcholine, but not substance P. Vasoconstrictor reactivity is not increased in preeclampsia compared with uncomplicated normal pregnancy, and this is unlikely to be an explanation for the increased peripheral vascular resistance seen in preeclampsia.