Intertwin anastomoses in monochorionic placentas after fetoscopic laser coagulation for twin-to-twin transfusion syndrome: Is there more than meets the eye?

doi:10.1016/j.ajog.2005.08.062

American Journal of Obstetrics and Gynecology

Volume 194, Issue 3, March 2006, Pages 790-795

https://doi.org/10.1016/j.ajog.2005.08.062 Get rights and content

Objective

This study was undertaken to detect missed anastomoses on the chorionic surface as well as hidden connections in the depth of the cotyledons in placentas after laser coagulation for twin-to-twin transfusion syndrome (TTTS) and to correlate these findings to clinical outcome.

Study design

All cord vessels were injected with dyed barium sulphate. A digital photograph of the chorionic surface angioarchitecture and single-shot digital X-ray (Rx) angiograms were made. The presence and diameter of any missed anastomoses on the chorionic surface and of any hidden angiographic connections were determined.

Results

Fifty placentas were analyzed, 7 of double intrauterine fetal death (IUFD) and 43 of double survivors. In 9 of 43 (21%) cases with double survival and in all 7 cases of double IUFD, missed anastomoses were identified that should have been ablated by laser coagulation (P < .001). There appeared to be a correlation between the type and diameter of missed anastomoses on the chorionic surface and the clinical outcome. Placentas with missed large arteriovenous/venoarterial anastomoses (AV/VA) (N = 8) were from cases with recurrent TTTS or double IUFD (unless compensated by a large arterioarterial anastomosis [AA]). Next, missed small AV/VA (N = 4) without AA resulted in isolated (ie, without TTTS) discordant hemoglobin levels requiring intrauterine transfusion. Finally, when there were no missed anastomoses (N = 34), TTTS had resolved in all cases and outcome was good, although 1 case had discordant hemoglobin values treated with a single intrauterine transfusion and 4 others had discordant hemoglobin at birth. On Rx angiography, potential hidden connections were present, all but 1 case.

Conclusion

Coagulation of all anastomoses visible on the chorionic surface seems adequate to treat TTTS. However, hidden connections in the depth of the cotyledon could not be excluded and may be involved in lesser degrees of intertwin transfusion.

Section snippets

Collection of placentas

The placentas originated from the participating centers within the Eurofoetus project, which were invited to send intact placentas from cases treated with fetoscopic laser coagulation for severe midgestational TTTS with either optimal outcome, ie, double survival into the third trimester or suspected surgical failure, such as double IUFD, recurrent TTTS, or isolated (ie, without TTTS) discordant hemoglobin levels. Fresh placentas were sent in a watertight container without any fixation. The

Results

Fifty-six placentas were sent in for analysis. Six placentas were not suitable for injection, 5 because of tissue fragmentation and 1 because of fixation in formalin. All remaining 50 placentas were successfully evaluated by both the dye method and Rx angiography within 1 to 4 days of delivery. Forty-three placentas belonged to double survivors delivered at a median GA of 30 weeks (range: 27-38). In all these double survivors, there was normalization of amniotic fluid levels after surgery,

Comment

This is an ex vivo study of monochorionic placentas of double survivors and double IUFDs treated with fetoscopic laser coagulation for severe TTTS. Our study demonstrates that laser can coagulate all visible anastomoses on the chorionic surface and that successful coagulation results in resolution of TTTS. However, missed anastomoses were found—what could be referred to as procedure-related failure—which led to double IUFD, recurrent TTTS or discordant hemoglobin values requiring intrauterine

Acknowledgments

I. Blickstein (Israel) is greatly thanked for his help in writing the manuscript. The other members of the EuroTwin2Twin Consortium are thanked for setting up the group: R. Vlietinck-C Derom (Leuven), M. van Gemert (Amsterdam), G. Barki (Tuttlingen), R. Denk (Munchen), C. Jackson (London).

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Cited by (0)

L. Lewi and J. Jani are beneficents from a grant of the European Commission in its 5th Framework Programme (#QLG1-CT-2002-01632 EuroTwin2Twin).

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General Obstetrics and Gynecology: ObstetricsIntertwin anastomoses in monochorionic placentas after fetoscopic laser coagulation for twin-to-twin transfusion syndrome: Is there more than meets the eye?

Objective

Study design

Results

Conclusion

Section snippets

Collection of placentas

Results

Comment

Acknowledgments

Am J Obstet Gynecol

Placenta

Am J Obstet Gynecol

Placenta

Obstet Gynecol Clin North Am

Am J Obstet Gynecol

General Obstetrics and Gynecology: Obstetrics
Intertwin anastomoses in monochorionic placentas after fetoscopic laser coagulation for twin-to-twin transfusion syndrome: Is there more than meets the eye?