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| Selective Laser Photocoagulation of Communicating Vessels (SLCPV) in Twin-Twin Transfusion Syndrome |
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| Twin-twin transfusion syndrome (TTTS) is a condition that occurs in approximately 10% of all twins that share a common placenta (monochorionic twins or identical twins). Most identical twins share blood through the blood vessels in their common placenta. In TTTS there is an unequal sharing of blood. The smaller twin (the donor twin) may not get enough blood while the larger twin (the recipient twin) becomes overloaded with too much blood. As a result of TTTS, the recipient twin can have excess amniotic fluid in the bag of waters (called polyhydramnois), may suffer from cardiac failure, and die. The other donor twin, may have a small amount of amniotic fluid (called oligohydramnios), reduced or absent urine, growth retardation, and die. The diagnosis of TTTS is made with an ultrasound evaluation which shows polyhydramnois (maximum vertical pocket of 8 cm or more) in the recipient twin, and oligohydramnios a maximum vertical pocket of 2 cm or less in the donor twin. TTTS does not behave the same way in all patients. Some cases are more severely affected than others. A classification of TTTS into five stages by severity has been developed by us. Stage I: Oligohydramnios in the donor twin (MVP of 2 cm or less), and polyhydramnois in the recipient twin (MVP of 8cm or more). The bladder of the donor baby is visible. Stage II: Along with the oligohydramnios and polyhydramnois, there is no visible bladder in the donor twin during the entire ultrasound evaluation. Stage III: One or both babies have ultrasound evidence of poor blood flow or “Critically Abnormal Dopplers” (CADs). Defined as the presence of at least one of the following: a) Absent or reverse end-diastolic velocity in the umbilical artery (no blood flow or reversed blood flow through the umbilical artery in the latter part of the cardiac cycle). b) Reverse flow in the ductus venosus (reversed blood flow in the vessel that goes through the liver to the heart). c) Pulsatile umbilical venous flow (blood is backed up from the heart into the umbilical vein) Stage IV: Hydrops in one or both babies. This means fluid accumulation in any part of the baby such as swelling of the head (scalp edema), abdomen (ascites), lungs (pleural effusion) or heart (pericardial effusion). This is evidence of heart failure. In stage 3 and 4, if the donor’s bladder is not seen the TTTS is classified as “classic”, if the donor’s bladder is seen, the TTTS is classified as atypical. Stage V: One or both babies have died. Expectant management, or “watchful waiting” of TTTS has been associated with a high death rate in the period shortly before and after birth (up to 95%). The purpose of selective laser coagulation of communicating vessels (SLPCV) is to separate the circulation between the babies by using laser energy to seal off the vessels connecting the two. As a result the babies no longer share blood vessels and the TTTS is cured. There are other blood vessels in the placenta that do not allow sharing of blood between the babies. These vessels feed areas of the placenta that belong to each twin. These vessels are not targeted or “selected” during laser surgery. Laser surgery may benefit you directly by allowing the pregnancy to continue and improve the odds of a successful outcome. The current figures estimate the outcomes for this procedure are as follows: 85% chance of at least one living fetus, 50-60% chance of both fetuses surviving, and 15% chance of losing both fetuses. Thus, laser surgery or SLPCV is emerging worldwide as the most effective treatment for TTTS. It is vitally important to continue collecting data about the risks and benefits of this procedure in order to adequately counsel and treat high risk patients with multiple gestation pregnancies complicated with TTTS. The objective of this study is to analyze maternal and neonatal outcomes of TTTS patients treated with SLPCV in an observational trial. All outcomes will be stratified by stage. Neonatal/infant morbidity and survival will be evaluated up to 6 months after birth. INCLUSION CRITERIA: 1) 18 – 55 years old 2) 16 – 26 weeks gestation 3) Confirmed TTTS meeting the following sonographic criteria a. Single placentab. Polyhydramnois: MVP > or = to 8cm in recipient twin, prior to amniodrainagec. Oligohydramnios: MVP < or = to 2 cm in donor twin, prior to amniodrainage d. Thin dividing membrane (absence of twin peak sign) or absence of dividing membrane e. Same gender, if visible 4) Prior therapeutic amniocentesis may be included 5) Anterior placenta may be included 6) Triplet gestations with two or three fetus sharing the same placenta may be included 7) Patients must give written informed consent EXCLUSION CRITERIA: 1) Presence of major congenital anomalies 2) Known unbalanced chromosomal complement 3) Prior intentional septostomy (purposely making a hole in the diving membrane) 4) Ruptured membranes 5) Chorioamnionitis 6) Abnormal intracranial findings 7) Placental abruption 8) Active labor 9) Any other patient deemed inappropriate for the study by the principle investigator |
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For further information, please contact: University of Southern California |
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