Correspondence
Twin–Twin Transfusion Syndrome
N Engl J Med 1995; 333:387-389August 10, 1995
- Article
To the Editor:
Regarding the article by Ville et al. entitled “Preliminary Experience with Endoscopic Laser Surgery for Severe Twin–Twin Transfusion Syndrome” (Jan. 26 issue),1 the patients in that study had therapeutic amniocentesis performed at the time of laser surgery, and therefore the relative contributions of laser surgery and therapeutic amniocentesis are blurred.
What is most striking about the report is the extraordinary frequency of catastrophic outcomes that appear to have been caused by the laser surgery — namely, fetal death in utero within 24 hours. This occurred in 50 percent of pregnancies (21 of 42, if 3 pregnancies in which selective feticide was performed are excluded), with 15 donor fetuses, 2 recipient fetuses, and 4 fetuses whose identity as donors or recipients was unknown dying first and within 24 hours. This would indicate that from 36 percent to as many as 45 percent of donor fetuses died as a result of the laser surgery. This complication is certainly not reported with therapeutic amniocentesis. Why does it occur? The answer is really unknown, but the surgery and the ablation of all visible vessels in the area of the connecting membrane must result in unfavorable cardiovascular changes, especially in the donor twin. It is certainly possible that there is a net reversal of flow from the recipient to the previous donor, which would result in sudden fluid overload in a baby with chronic hypovolemia.
The Discussion section contains some troublesome recommendations. The authors state, “Furthermore, the data suggest that this treatment may be associated with a higher survival rate and a lower risk of cerebral palsy than treatment with serial drainage of amniotic fluid.” Their data do not support either claim. The overall outcome in this series shows a survival of 53 percent, as compared with survival approaching 66 to 79 percent in several series of therapeutic amniocentesis.2,3 Nor can the statement about the incidence of cerebral palsy be substantiated. Cerebral palsy has been documented in patients with the twin–twin transfusion syndrome. It has occurred consistently in donor twins and is probably related to hypovolemia that leads to cerebral ischemia. In this study, there were only 17 donor twins who survived and could be evaluated for cerebral palsy. That group is entirely too small for any kind of statement to be made about the incidence of cerebral palsy associated with laser surgery. The problem of potential abnormality of the central nervous system is real, and more research needs to be done to identify the mechanism of injury and any interventions that can reduce the incidence of this complication.
3 ReferencesJohn P. Elliott, M.D.
Good Samaritan Regional Medical Center, Phoenix, AZ 850061
Ville Y ,Hyett J ,Hecher K ,Nicolaides K . Preliminary experience with endoscopic laser surgery for severe twin-twin transfusion syndrome. N Engl J Med 1995;332:224-227
Full Text | Web of Science | Medline2
Reisner DP ,Mahony BS ,Petty CN , et al. Stuck twin syndrome: outcome in thirty-seven consecutive cases. Am J Obstet Gynecol 1993;169:991-995
Web of Science | Medline3
Elliott JP ,Urig MA ,Clewell WH . Aggressive therapeutic amniocentesis for treatment of twin-twin transfusion syndrome. Obstet Gynecol 1991;77:537-540
Web of Science | Medline
To the Editor:
Ville et al. claim that laser coagulation of placental vessels is an effective treatment for the twin–twin transfusion syndrome and is associated with a higher survival rate than serial amniocentesis. Perinatal survival in their series was only 53 percent (48 of 90 fetuses). These results are especially poor for two reasons. First, Ville et al. performed amniocentesis at the time of laser therapy. Second, the range in the size of the deepest vertical pockets of amniotic fluid before surgery (8 to 18 cm) indicated that some patients had polyhydramnios that was only mild, not severe as claimed. In contrast to the results of Ville et al., perinatal survival in recent series using aggressive serial amniocentesis was 74 to 83 percent,1-3 in accordance with our own experience. An exception was the 37 percent survival rate reported by the same group from King's College Hospital.4 However, one third of those losses were spontaneous abortions within 48 hours of the procedure, and it is difficult to envisage why this risk would be averted by laser surgery, which necessarily involves concomitant amniocentesis.
We have recently reported controlled perfusion experiments in monochorial placentas showing that pregnancies with the twin–twin transfusion syndrome have significantly fewer anastomoses than those without the syndrome.5 In particular, the syndrome is characterized by a paucity of superficial anastomoses (usually one or none). Previous reports of laser coagulation, however, document ablation of 6 to 10 superficial vascular anastomoses. Ville et al. describe the identification of communicating vessels by color Doppler and the successful coagulation of all crossing vessels. Because the intertwin septum bears little relation to the vascular equator,5 we suggest that they are instead largely ablating normal chorionic-plate vessels. This would explain the necrosis of the full thickness of the placenta seen after laser surgery6 and the high rate of intrauterine death within 24 hours of the procedure (in 50 percent of pregnancies in the series of Ville et al.). Indeed, selective feticide is considered a “successful” therapy by some, in that it can lead to a resolution of the condition, although there can be only one survivor.
Although the report by Ville et al. represents a considerable technical achievement, we cannot agree that laser ablation as currently practiced is an effective treatment for the twin–twin transfusion syndrome.
6 ReferencesNicholas M. Fisk, M.B., Ph.D.
Rekha Bajoria, M.B., Ph.D.
Jonathan Wigglesworth, M.D.
Royal Postgraduate Medical School, London W6 OXG, United Kingdom1
Pinette MG ,Pan Y ,Pinette SG ,Stubblefield PG . Treatment of twin-twin transfusion syndrome. Obstet Gynecol 1993;82:841-846
Web of Science | Medline2
Reisner DP ,Mahony BS ,Petty CN , et al. Stuck twin syndrome: outcome in thirty-seven consecutive cases. Am J Obstet Gynecol 1993;169:991-995
Web of Science | Medline3
Elliott JP ,Urig MA ,Clewell WH . Aggressive therapeutic amniocentesis for treatment of twin-twin transfusion syndrome. Obstet Gynecol 1991;77:537-540
Web of Science | Medline4
Saunders NJ ,Snijders RJ ,Nicolaides KH . Therapeutic amniocentesis in twin-twin transfusion syndrome appearing in the second trimester of pregnancy. Am J Obstet Gynecol 1992;166:820-824
Web of Science | Medline5
Bajoria R ,Wigglesworth J ,Fisk NM . Angioarchitecture of monochorionic placentas in relation to the twin-twin transfusion syndrome. Am J Obstet Gynecol 1995;172:856-863
CrossRef | Web of Science | Medline6
De Lia JE ,Cruikshank DP ,Keye WR Jr . Fetoscopic neodymium:YAG laser occlusion of placental vessels in severe twin-twin transfusion syndrome. Obstet Gynecol 1990;75:1046-1053
Web of Science | Medline
Author/Editor Response
The authors reply:
To the Editor: In the period 1988 to 1992 we performed serial amniocentesis in 25 pregnant women who had severe twin–twin transfusion syndrome presenting with acute second-trimester polyhydramnios. Sixteen babies survived (32 percent), and four of the survivors (25 percent) had cerebral palsy. This high proportion of handicap prompted us to seek an alternative therapy. Since 1992 we have performed endoscopic laser coagulation in 75 pregnant women who met diagnostic criteria identical to those of the serial-amniocentesis group. In one case, the depth of amniotic fluid was only 8 cm, but at 15 weeks of gestation this constitutes severe polyhydramnios. In 54 of the pregnancies (72 percent) there was at least 1 survivor, and a total of 79 babies survived (53 percent). Only one baby, diagnosed antenatally to have microcephaly, had cerebral palsy. These data suggest that laser coagulation is associated with both higher survival and a substantially reduced risk of cerebral palsy, as compared with serial amniocentesis, and the findings are compatible with those of another study that used laser coagulation to treat this condition.1
More than 20 years ago, Benirschke and Kim reported that the arteriovenous anastomoses underlying the twin–twin transfusion syndrome are found deep in the common cotyledons.2 However, their afferent and efferent branches are superficial, and although the intertwin membrane does not necessarily overlie these common cotyledons, the coagulation of all crossing vessels will inevitably include the branches of these anastomoses. A problem with laser coagulation that may have contributed to the high mortality rate of the donor fetuses is that coagulation may interrupt more than the vascular supply to the common cotyledon, destroying whatever little reserve there is in an already compromised placenta. The extent to which we can restrict coagulation to the common cotyledons remains to be determined, as does the potential increase in survival without handicap.
The results in our serial-amniocentesis group were similar to those in series reported before 1992 and compare favorably with the mean survival of 5 percent in studies in which no intervention was used.3 In the past three years, three centers (as indicated in the letters of Fisk et al. and Elliott) have reported that in 53 pregnancies treated with serial amniocentesis and in 9 managed with watchful waiting, the fetal survival rates were 76 percent and 56 percent, respectively, suggesting that the condition was milder than in previous studies. In addition, the largest series included dichorionic pregnancies.4 Reisner et al. also reported that 36 percent of the survivors of amniocentesis had cerebral palsy.4
4 ReferencesYves Ville, M.D.
Jon Hyett, M.D.
Kypros Nicolaides, M.D.
King's College School of Medicine and Dentistry, London SE5 8RX, United Kingdom1
De Lia JE ,Kuhlmann RS ,Harstad TW ,Cruikshank DP . Fetoscopic laser ablation of placental vessels in severe previable twin-twin transfusion syndrome. Am J Obstet Gynecol 1995;172:1202-1211
CrossRef | Web of Science | Medline2
Benirschke K ,Kim CK . Multiple pregnancy. N Engl J Med 1973;288:1276-1284
Full Text | Web of Science | Medline3
Saunders NJ ,Snijders RJ ,Nicolaides KH . Therapeutic amniocentesis in twin-twin transfusion syndrome appearing in the second trimester of pregnancy. Am J Obstet Gynecol 1992;166:820-824
Web of Science | Medline4
Reisner DP ,Mahony BS ,Petty CN , et al. Stuck twin syndrome: outcome in thirty-seven consecutive cases. Am J Obstet Gynecol 1993;169:991-995
Web of Science | Medline
- Citing Articles (2)
Citing Articles
1
J. M. Middeldorp, E. Lopriore, F. P. H. A. Vandenbussche. (2005) Foetoscopische lasercoagulatie van placentaire anastomosen als behandeling van het tweelingtransfusiesyndroom. Tijdschrift voor kindergeneeskunde 73:4, 101-109
CrossRef2
Martin van Gemert, Asli Umur, Jan Tijssen, Michael Ross. (2001) Current Opinion in Obstetrics & Gynecology 13:2, 193
CrossRef
