TWIN REVERSED ARTERIAL PERFUSION CAUSES DECREASED FETAL CEREBRAL VASCULAR IMPEDANCE

Abstract

HHS Public Access Author manuscript Author Manuscript Ultrasound Obstet Gynecol. Author manuscript; available in PMC 2015 July 15. Published in final edited form as: Ultrasound Obstet Gynecol. 2015 April ; 45(4): 447–451. doi:10.1002/uog.14650. Twin-reversed arterial perfusion sequence associated with decreased fetal cerebral vascular impedance S. Peyvandi *,† , V. A. Feldstein †,‡,§ , S. Hirose †,¶ , L. Rand †,§ , M. M. Brook *,† , and A. J. Moon- Grady *,† * Division of Cardiology, Department of Pediatrics, University of California San Francisco Benioff Children’s Hospital, San Francisco, CA, USA Author Manuscript † The Fetal Treatment Center, University of California San Francisco Benioff Children’s Hospital, San Francisco, CA, USA ‡ Department of Radiology, University of California San Francisco, San Francisco, CA, USA § Department of Obstetrics and Gynecology, University of California San Francisco, San Francisco, CA, USA ¶ Division of Pediatric Surgery, Department of Surgery, University of California San Francisco Benioff Children’s Hospital, San Francisco, CA, USA Abstract Author Manuscript Objectives—Twin-reversed arterial perfusion (TRAP) sequence affects 1% of monochorionic twin pregnancies and is caused by abnormal vascular connections between a pump twin and an acardiac mass. The effects of abnormal vascular connections on cerebral vasculature in the pump twin are unknown. We hypothesize that abnormal cerebral vascular impedance, as assessed by the pulsatility index (PI), is present in pump twins and that fetal intervention alters cerebral impedance. Methods—Fetal echocardiograms performed between 2010 and 2013 in pregnancies diagnosed with TRAP (n = 19), recorded at presentation, and uncomplicated monochorionic twin pregnancies (controls, n = 18; 36 fetuses) were analyzed. In all subjects, the middle cerebral artery (MCA)-PI, combined cardiac output (CCO) and cardiothoracic ratio were calculated, and the values for cases and controls were compared. Author Manuscript Results—The mean gestational age at the time of echocardiography was 20 weeks in both groups. MCA-PI was lower in TRAP cases than in controls (1.55 (95%CI, 1.47–1.64) vs 1.74 (95% CI, 1.65–1.82), respectively; P = 0.004). CCO in TRAP cases was mildly elevated for gestational age (199.7 (95% CI, 138.4–261.1) mL/min) compared with that of controls (131.4 (95% CI, 102.2–160.7) mL/min). In six TRAP cases with a second echocardiogram available, the mean MCA-PI increased after intervention, from 1.5 (95%CI, 1.3–1.7) to 1.8 (95% CI, 1.4–2.2). Conclusions—TRAP pump twins have lower cerebral vascular impedance than do controls, suggestive of a brain-sparing effect. MCA-PI appeared to increase in a small group of pump twins Correspondence to: Dr S. Peyvandi, Department of Pediatrics, University of California San Francisco Benioff Children’s Hospital, 505 Parnassus Ave Box 0214, San Francisco, CA 94143, USA (shabnam.peyvandi@ucsf.edu).