Assessment of extremely premature lambs supported by the Extrauterine Environment for Neonatal Development (EXTEND).

BACKGROUND: Our team has previously reported physiologic support by the EXTra-uterine Environment for Neonatal Development (EXTEND) of 105 to 117 days gestational age (GA) lambs for up to 28 days with normal organ maturation. However, the fetal lamb brain matures more rapidly, requiring the study of 90-105 day GA fetal lambs to assess more neurodevelopmentally equivalent lambs to the 23-25 week GA extreme premature infant. METHODS: Extremely preterm lambs (90-95 days of GA) were delivered by C-section and supported by EXTEND. Estimated circuit flows were maintained at around 325 ml/kg/min. After support on EXTEND, MRI and histopathologic analysis were performed and compared to 105-112 days GA control lambs. RESULTS: The extremely preterm group includes 10 animals with a mean GA of 91.6 days, a mean weight at cannulation of 0.98 kg and a mean length of stay on EXTEND of 13.5 days (10-21 days). Hemodynamics and oxygenation showed stable parameters. Animals showed growth and physiologic cardiac function. MRI volumetric and diffusion analysis was comparable to controls. Histologic brain analysis revealed no difference between study groups. CONCLUSION: EXTEND appears to support brain and cardiac development in an earlier gestation, less mature, lamb model. IMPACT: Prolonged (up to 21 days) physiological support of extremely preterm lambs of closer neurodevelopmental equivalence to the 24-28 gestational week human was achieved using the EXTEND system. EXTEND treatment supported brain growth and development in extremely preterm fetal lambs and was not associated with intraventricular hemorrhage or white matter injury. Daily echocardiography demonstrated physiologic heart function, absence of cardiac afterload, and normal developmental increase in cardiac chamber dimensions. This study demonstrates hemodynamic and metabolic support by the EXTEND system in the extremely preterm ovine model.

Fetal Doppler Echocardiographic Assessment Predicts Severe Postnatal Obstruction in Total Anomalous Pulmonary Venous Connection.

BACKGROUND: Obstructed total anomalous pulmonary venous connection (TAPVC) is a form of critical congenital heart disease that usually requires urgent postnatal intervention. Knowing which patients have severe obstruction can aid delivery planning. The authors previously developed a novel quantitative metric of pulmonary venous flow, the pulmonary venous variability index (PVVI). The aim of this study was to test the hypothesis that fetal PVVI and vertical vein Doppler velocities are associated with severe pulmonary vein obstruction postnatally. METHODS: A retrospective cohort study of neonates with prenatally diagnosed TAPVC was performed. Patients who underwent fetal echocardiography at the Children's Hospital of Philadelphia with Doppler interrogation of the vertical vein were included for analysis. Twenty-nine patients met criteria (21 with heterotaxy, 18 with supracardiac TAPVC). The latest gestation fetal echocardiogram was used. Severe pulmonary vein obstruction was defined as preoperative death or urgent surgery or catheter-based intervention (first day of life). Measurements of PVVI, defined as (maximum velocity - minimum velocity)/mean velocity, were made offline. Wilcoxon rank sum models were used to assess the associations of severe obstruction and PVVI and maximum, mean, and minimum velocities. RESULTS: The mean gestational age at the latest fetal echocardiographic examination was 35 weeks (range, 30-39 weeks). Twelve of the 29 patients (41%) met criteria for severe pulmonary vein obstruction. Lower PVVI was associated with greater risk for severe pulmonary venous obstruction (P = .008). The maximum, mean, and minimum velocities in the vertical vein were all significantly associated with severe pulmonary venous obstruction (P = .03, P = .03, and P = .007, respectively). Qualitative assessment of obstruction was not significantly associated with the outcome. Interobserver reliability for all vertical vein Doppler metrics was high (intraclass correlation coefficient > 0.9). CONCLUSIONS: Fetal PVVI and maximum, mean, and minimum velocities are associated with severe postnatal pulmonary vein obstruction in TAPVC. Accurate prediction of obstructed TAPVC could allow safer delivery planning. Further research with larger sample sizes is needed to identify the ideal cutoff values for these Doppler measures.

Evaluation of umbilical venous flow volume measured using ultrasound compared to circuit flow volume in the EXTra-uterine Environment for Neonatal Development (EXTEND) system in fetal sheep.

OBJECTIVE: To compare and validate umbilical venous flow volume (UVFV) measured at the intra-abdominal portion using ultrasound with actual flow volume of umbilical vein (UV) in fetal sheep sustained on the EXTrauterine Environment for Neonatal Development (EXTEND) system. METHODS: Circuit flow volume through the oxygenator was obtained using sensors. Ultrasound derived UVFV (ml/min) was calculated as (UV diameter [cm]/2)2 × 3.14 × maximum velocity (cm/s) × 0.5 × 60, measured at approximately the mid portion between its abdominal insertion and the origin of the ductus venosus. UVFV was measured by ultrasound once daily and was compared to the average of daily circuit flow volume directly measured. RESULTS: UVFV was measured 168 times in 15 fetal sheep. The ratio of circuit flow volume to combined cardiac output remained stable within the anticipated physiological range throughout. UVFV measured by ultrasound showed good correlation to directly measured circuit flow (r = 0.72). Interclass correlation coefficients for intra-observer variability was 0.991 (95% confidence interval [CI], 0.979-0.996). CONCLUSION: UVFV measured at the intra-abdominal portion using ultrasound shows a good correlation with directly measured circuit flow volume in UV of fetal sheep on the EXTEND system. Regular incorporation of such validated UVFV measures into clinical use may offer opportunities to better understand conditions of placental dysfunction.

Characterization of Placental Microvascular Architecture by MV-Flow Imaging in Normal and Fetal Growth-Restricted Pregnancies.

OBJECTIVES: To observe the microvascular architecture in the placental bed and explore the feasibility and clinical utility of MV-Flow imaging (Samsung Medison Co, Ltd, Seoul, Korea) during normal pregnancy and fetal growth restriction (FGR). METHODS: Placental microvascular structure ultrasound imaging by MV-Flow was performed on 227 unaffected and 17 FGR fetuses between 11 and 41 weeks' gestation. A placental vascular index (VIMV ) was acquired by application of various MV-Flow regions of interest (ellipse, rectangle, and manual trace). Unaffected control and FGR groups were assessed for umbilical artery, middle cerebral artery, and uterine artery pulsatility indices and the cerebroplacental ratio calculated by ultrasound. RESULTS: No significant difference in the VIMV by varying regions of interest or placental regions was observed in the control group. The VIMV in the first trimester was lower than that in the second and third trimesters, with 5th through 95th percentile normal VIMV reference values of 18.39 to 63.79 for 13.6 weeks and earlier, 28.53 to 66.64 for 14 weeks to 27 weeks 6 days, and 21.95 to 67.45 for 28 weeks and later. The VIMV values in the FGR group were lower than those in the control group in the upper, middle, and lower parts of the placenta (mean ± SD, 24.9 ± 13.9 versus 45.0 ± 13.4; P < .01; 30.5 ± 16.1 versus 44.7 ± 14.3; P < .01; and 29.9 ± 17.4 versus 47.6 ± 12.2; P < .01, respectively). Higher umbilical artery and uterine artery pulsatility indices and a lower cerebroplacental ratio were found in the FGR group compared with the control group (P < .01). CONCLUSIONS: MV-Flow technology can display and quantify placental microvascular architecture at the level of the stem villi and villous leaves, and the VIMV provides for quantification of tissue vascularity. MV-Flow is a potentially powerful and promising tool to explore placental microvascular perfusion and provide new information on a host of pregnancy-related conditions.

Mid-gestational fetal placental blood flow is diminished in the fetus with congenital heart disease.

OBJECTIVE: Data suggest fetuses with congenital heart disease (CHD) have placental abnormalities. Their abnormal placental vasculature may affect fetal placental blood flow, which has not previously been explored. METHOD: We performed a retrospective cross-sectional study comparing umbilical venous volume flow (UVVF) of single ventricle, D-transposition of the great arteries, and tetralogy of Fallot fetuses with fetuses without CHD. UVVF and combined cardiac output (CCO) were calculated from fetal echocardiography and compared using t tests, χ2 and Fisher's exact tests. RESULTS: Mean gestational age and fetal weight were greater in CHD fetuses (26.5 weeks, 1119.4 g; n = 81, P < .001) compared to controls (23.1 weeks, 675 g; n = 170, P < .001). UVVF/fetal weight was nevertheless decreased among cases (99.8 vs 115.3 mL/min/kg, P < .001). Subgroup analysis of 20- to 25-week fetuses demonstrated no significant differences in case and control baseline characteristics. In CHD fetuses (n = 31) compared to controls (n = 144), absolute UVVF (50.8 vs 62.1 mL/min, P = .006), and UVVF/fetal weight (98.8 vs 118.5 mL/min/kg, P < .001) were decreased. Findings were similar in single ventricle (n = 24) and hypoplastic left heart syndrome (n = 14). CONCLUSION: Mid-gestational placental blood flow in CHD fetuses is decreased compared to controls. Further study is needed to explore the relationship between UVVF and placental pathology, and impact on outcomes.

Characterization of the Placenta in the Newborn with Congenital Heart Disease: Distinctions Based on Type of Cardiac Malformation.

The placenta is a complex organ that influences prenatal growth and development, and through fetal programming impacts postnatal health and well-being lifelong. Little information exists on placental pathology in the presence of congenital heart disease (CHD). Our objective is to characterize the placenta in CHD and investigate for distinctions based on type of malformation present. Placental pathology from singleton neonates prenatally diagnosed and delivered at > 37 weeks gestation was analyzed. Placental findings of absolute weight, placental weight-to-newborn birth weight ratio, chorangiosis, villus maturity, thrombosis, and infarction were recorded and analyzed based on four physiological categories of CHD: (1) single ventricle-aortic obstruction, (2) single ventricle-pulmonic obstruction, (3) two-ventricle anomalies, and (4) transposition of the great arteries (TGA). Associations between fetal Doppler assessments of middle cerebral/umbilical arterial flow and placental findings were investigated. A total of 120 cases of complex CHD were analyzed. Overall placental-to-birth weight ratios were < 10th percentile for 77% and < 3rd percentile for 49% with abnormalities of chorangiosis (18%), hypomature villi (15%), thrombosis (41%), and infarction (17%) common. There was no association between fetal Doppler flow measures and placental abnormalities. Newborns with TGA had the greatest degree of placental abnormality. Placentas of newborns with CHD are smaller than expected and manifest a number of vascular abnormalities, with TGA most prominent. Fetal Doppler does not correlate with these abnormalities. Studies investigating the relationship between placental abnormalities and postnatal outcomes may offer insight into the fetal origins of outcome variability in CHD.

Prenatal Echocardiographic Predictors of Postnatal Management Strategy in the Fetus with Right Ventricle Hypoplasia and Pulmonary Atresia or Stenosis.

Fetuses with pulmonary atresia or pulmonary stenosis with intact ventricular septum manifest variable degrees of right ventricle hypoplasia and inadequacy. We studied the relationship between prenatal echocardiographic parameters and their progression through gestation as potential predictors of postnatal single-ventricle or two-ventricle care strategy. Serial fetal echocardiograms of pulmonary atresia (n = 28) or severe pulmonary stenosis (n = 8) and intact ventricular septum were reviewed. Measurements included tricuspid valve and mitral valve diameter and Z scores, degree of tricuspid regurgitation, presence of subaortic stenosis, presence of coronary artery fistulae, and Doppler pulsatility indices in middle cerebral and umbilical artery. Data were compared between first and last fetal studies. Subjects were divided based on postnatal course of single- or two-ventricle repair. Tricuspid valve size of those destined for single ventricle is smaller than of those destined for a two-ventricle repair at first study (26w, Z score -4.22 v -1.83, p < 0.001) and at final study (35w, -4.94 v -1.42, p < 0.001). Tricuspid valve and right ventricle grow in those destined for two ventricle, but not single-ventricle palliation. Tricuspid valve Z score = -3 at first or last study discriminated between single- or two-ventricle repair, except in two unusual cases with significant subaortic stenosis. Tricuspid valve Doppler-derived parameters of middle cerebral artery and umbilical artery did not distinguish between groups. In the fetus with pulmonary atresia or stenosis and intact ventricular septum, tricuspid valve Z score ≥-3, presence of important tricuspid regurgitation, absence of coronary fistulae, and absence of subaortic stenosis are associated with a two-ventricle postnatal strategy.

Persistent Left Superior Vena Cava Connected to the Coronary Sinus in the Fetus: Effects on Cardiac Structure and Flow Dynamics.

Ventricular size discrepancy may be due to a persistent left superior vena cava (PLSVC) in utero. We sought to investigate for differences in cardiac structure measures and hemodynamics between fetuses with isolated PLSVC connected to the coronary sinus (CS) and normal. Fetuses diagnosed with isolated PLSVC in the second and third trimester were enrolled. We defined two groups: group 1, twenty-five fetuses in the second trimester (22-27 W + 6d); group 2, twenty-two fetuses in the third trimester (28-39 W + 6d). Fifty-three fetuses without intra-cardiac or extra-cardiac anomalies and gestation age-matched were divided into normal control groups: group 3, 28 fetuses in the second trimester; group 4, 25 fetuses in the third trimester. Parameters of cardiac structure and hemodynamics were measured, including: left- and right-side heart size, the diameter of foramen ovale, aorta (AO), aortic isthmus and pulmonary artery (PA), and ratios of cardiac structure RV/LV, RA/LA and PA/AO were calculated. Hemodynamic parameters measured included: flow velocity across mitral valve, tricuspid valve and foramen ovale. In the second trimester, the ratio of RV/LV and PA/AO of the PLSVC fetuses was significantly larger than normal, while the AO diameter, aortic isthmus diameter were smaller than normal (P < 0.05). However, in the third trimester, only the ratio of PA/AO of the PLSVC fetuses was significantly larger, and the aortic isthmus diameter was still smaller than normal (P < 0.05). Isolated PLSVC connecting to the CS is associated with differences in cardiac structure size from normal. These differences appear to diminish with gestational age. A dilated CS may have an influence on development of fetal left heart structures.

Anatomic variability and outcome in prenatally diagnosed absent pulmonary valve syndrome.

BACKGROUND: We sought to describe current outcomes and risk factors for mortality for fetuses diagnosed with absent pulmonary valve syndrome (APV). Fetuses with APV were divided into two cohorts, those with underlying tetralogy of Fallot (TOF/APV) and those without underlying TOF and either an intact ventricular septum or small ventricular septal defect (APV/IVS). METHODS: The fetal echocardiographic database was reviewed from January 1, 2001, until June 1, 2010, and all subjects with a diagnosis of APV were included. Multiple clinical and fetal echocardiographic measurements were recorded. Statistical analysis was performed by χ2 analysis and t tests. Survival analysis was performed by Kaplan-Meier analysis. Significant relationships between variables were explored by regression analysis. Significance was set at p=0.05. RESULTS: The cohort consisted of 15 fetuses with TOF/APV and 6 fetuses with APV/IVS. There were no fetal demises in either cohort. Survival to birth was 71% in the TOF/APV cohort and 83% in the APV/IVS cohort (p=0.62). Of subjects born alive, survival was 80% for both cohorts (p=0.95). However, in the APV/IVS cohort, transplantation-free survival was only 20%. Underlying single-ventricle physiology strongly predicted those who underwent heart transplantation (p=0.003, R2=0.50). For the entire APV cohort, left ventricular dysfunction (p=0.005, R2=0.41) and a higher pulmonary artery valve-to-aortic valve ratio (p=0.02, R2=0.34) predicted mortality. CONCLUSIONS: Postnatal outcomes continue to improve for fetuses with APV syndrome. Left ventricular dysfunction and higher pulmonary artery valve-to-aortic valve ratio accurately predict postnatal mortality for fetuses with APV.

Right ventricular mechanics in the fetus with hypoplastic left heart syndrome.

BACKGROUND: Right ventricular mechanics influence outcomes in patients with hypoplastic left heart syndrome (HLHS). The aim of this study was to determine whether differences in right ventricular performance have their origins in fetal life and if the architectural character of the hypoplastic left ventricle affects right ventricular mechanics. METHODS: The first complete fetal echocardiograms after 17 weeks' gestation were reviewed in 84 fetuses with HLHS and in 115 gestational age-matched normal controls. Inflow, outflow, and myocardial tissue Doppler velocities were measured. E/A and E/e' ratios and right ventricular myocardial performance index were calculated. RESULTS: In fetuses with HLHS, there were lower tricuspid E/A ratios (mean, 0.6 ± 0.1 vs 0.7 ± 0.1; P < .001), higher E/e' ratios (mean, 8.1 ± 2.6 vs 7.0 ± 1.3; P = .006), and higher right ventricular myocardial performance indices (mean, 0.47 ± 0.14 vs 0.40 ± 0.10; P < .001) compared with controls. Among fetuses with HLHS grouped according to left ventricular architecture, those with left ventricular endocardial fibroelastosis had the most striking differences in right ventricular mechanics. CONCLUSIONS: Right ventricular mechanics are different from normal in fetuses with HLHS and are influenced by the presence of left ventricular endocardial fibroelastosis. These differences precede the imposition of undue loading conditions as a consequence of surgical palliation and may offer clues to the development of later right ventricular failure.

Speckle tracking-derived myocardial tissue deformation imaging in twin-twin transfusion syndrome: differences in strain and strain rate between donor and recipient twins.

OBJECTIVES: Twin-twin transfusion syndrome (TTTS) is a complex disorder with altered cardiovascular loading conditions that affects both donors and recipients. Myocardial tissue deformation analysis using vector velocity imaging is an angle-independent, speckle-tracking technique which can assess myocardial mechanics and may provide insight into cardiac dysfunction in TTTS. METHODS: Digital dynamic two-dimensional four-chamber views were interrogated offline. Images were acquired utilizing standard video frame rates (30 frames/s). The global longitudinal strain, systolic strain rate, and diastolic strain rate were measured in the left (LV) and right ventricles (RV) of 25 fetal pairs with TTTS and compared to 25 gestational age-matched normal controls. Pulsatility indices for the umbilical artery and middle cerebral artery were measured. RESULTS: The gestational age at evaluation was 20.5 ± 1.3 weeks. The donor LV systolic strain rate was higher, while the donor RV diastolic strain rate was significantly lower, than control values. The recipient longitudinal strain, systolic strain rate, and diastolic strain rate were significantly lower for both LV and RV in comparison to controls. The donor umbilical artery pulsatility index was higher than control values (1.92 ± 0.45 vs. 1.41 ± 0.25, p < 0.001), while the donor middle cerebral artery pulsatility index was lower (1.46 ± 0.28 vs. 1.87 ± 0.21). Recipient umbilical artery and middle cerebral artery pulsatility indices were no different than control values. CONCLUSIONS: In TTTS, both the donor and the recipient exhibit abnormalities of myocardial tissue deformation with ventricle-specific changes evident based on loading conditions. Donor LV systolic function is hyperdynamic due to hypovolemia and selective ejection into a low-resistance cerebrovascular circuit while the donor RV selectively ejects into a high-resistance placental circuit. Recipient RV and LV are both globally depressed with systolic and diastolic dysfunction. Further prospective validation of our findings using high frame rate analysis is indicated.

Perinatal course of Ebstein's anomaly and tricuspid valve dysplasia in the fetus.

OBJECTIVE: We sought to better define echocardiographic predictors of perinatal mortality in fetuses with Ebstein's anomaly (EA) or tricuspid valve dysplasia (TVD). METHOD: Parameters included measured chamber size, the presence of hydrops, and Doppler recordings of the left ventricular (LV) myocardial performance index (MPI). RESULTS: Between 1 January 2000 and 31 December 2008, 21 fetuses were diagnosed with either EA (17) or TVD (4). Five fetuses were lost to follow-up, and 12 of 16 fetuses were born live (75%). Survivors were found to have smaller right atrial area index scores when compared with non-survivors (1.025 ± 0312 vs 1.502 ± 0.105, respectively, p = 0.013) and were less likely to present with hydrops (0% survivors vs 75% of non-survivors, p < 0.01). LV MPI sub-analysis revealed a shorter combined isovolemic contraction and relaxation time for non-survivors compared wth survivors (46.5 ± 8.2 ms vs 82.3 ± 21.2 ms, respectively, p = 0.004) although no difference was observed for LV ejection times or overall LV MPI between survivors and non-survivors. CONCLUSION: Physiologic analysis of left ventricular function via the LV Tei index and its component measurements demonstrates potentially novel insights into hemodynamic derangements and their association with outcomes in patients with EA/TVD.

[Impact of selective fetoscopic laser photocoagulation for twin-twin transfusion syndrome on myocardial deformation].

OBJECTIVE: To investigate the changes in myocardial deformation in donor and recipient hearts in response to selective fetoscopic laser photocoagulation (SFLP) for twin-twin transfusion syndrome (TTTS). METHODS: Totally 25 twin pairs before 24-hour and 1 week after SFLP had fetal echocardiography and digital dynamic two-dimensional four chamber views which were interrogated off-line using velocity vector imaging (VVI) software. Global longitudinal strain (S), systolic strain rate (SRs) and diastolic strain rate (SRd) were measured off-line in the left (LV) and right (RV) ventricles. RESULTS: In the donor, SFLP resulted in increase in cardiothoracic ratio (CTR, 0.29 ± 0.03 versus 0.34 ± 0.05, P < 0.01), with development of new onset tricupid regurgitation (n = 7) and pericardial effusion (n = 5) and worsening of all measures of myocardial deformation in both systole and diastole for LV and RV [LV-S: (-19.24 ± 3.68)% versus (-13.78 ± 3.64)%, P < 0.01; LV-SRs: (-2.28 ± 0.53) versus (-1.43 ± 0.41) s(-1), P < 0.01; LV-SRd: (1.67 ± 0.43) versus (1.15 ± 0.70) s(-1), P < 0.01; RV-S: (-20.20 ± 3.19)% versus (-16.10 ± 3.07)%, P < 0.01; RV-SRs: (-2.03 ± 0.65) versus (-1.72 ± 0.38) s(-1), P < 0.05; RV-SRd: (1.71 ± 0.30) versus (1.50 ± 0.36) s(-1), P < 0.05]. In the recipient, CTR decreased (0.42 ± 0.04 versus 0.37 ± 0.04, P < 0.01) and all parameters for both LV and RV improved substantially [LV-S: (-10.62 ± 2.72)% versus (-16.46 ± 3.23)%, LV-SRs: (-1.09 ± 0.30) versus (-1.60 ± 0.31) s(-1), LV-SRd: (0.99 ± 0.34) versus (1.53 ± 0.32) s(-1), RV-S: (-11.66 ± 4.56)% versus (-17.96 ± 3.97)%, RV-SRs: (-1.26 ± 0.39) versus (-1.74 ± 0.45) s(-1), RV-SRd: (1.15 ± 0.49) versus (1.63 ± 0.44) s(-1); all P < 0.01]. CONCLUSION: Myocardial deformational mechanics improve in the recipient but worsen in the donor following SFLP for TTTS.

Vasoreactive response to maternal hyperoxygenation in the fetus with hypoplastic left heart syndrome.

BACKGROUND: Cardiopulmonary interactions play an important role in the pathophysiology of hypoplastic left heart syndrome (HLHS). Pulmonary vasculopathy has been identified, especially in those with restrictive/intact atrial septum. Responsiveness of the pulmonary vasculature to maternal hyperoxygenation (MH) may provide a tool to assess the degree of pulmonary vasculopathy present before birth. METHODS AND RESULTS: Doppler echocardiography was performed in 27 normal and 43 HLHS fetuses. In HLHS, sampling was repeated after 10 minutes of MH with 60% FiO(2) and after 5 minutes of recovery. Sampling was performed in the proximal, midportion, and distal branch pulmonary artery (PA). Pulsatility index (PI) was used as a measure of vascular impedance. Of the HLHS fetuses, 34 had an open interatrial septum and 9 had a restrictive/intact atrial septum. At birth, 5 fetuses underwent immediate intervention on the interatrial septum. Middle cerebral artery PI was lower in HLHS versus normal fetuses (P<0.001). There was no difference in UA, DA, or branch PA PI between normal fetuses and those with HLHS. MH led to a significant decrease in PI at each of the PA sites sampled in fetuses with an open atrial septum (P<0.001); however, there no was significant change in the PI in fetuses that required immediate intervention on the atrial septum at birth. Using a cutoff value of <10% vasoreactivity, the sensitivity of MH testing for determining need for immediate intervention at birth is 100% (0.46 to 1.0); specificity, 94% (0.78 to 0.99); positive predictive value, 71% (0.30 to 0.95); and negative predictive value, 100% (0.86 to 1.0). No untoward effects were seen with MH. CONCLUSIONS: PA vasoreactivity to MH occurs in the fetus with HLHS. MH testing accurately identifies fetuses requiring urgent postnatal intervention at birth and may be used to select candidates for fetal atrial septoplasty.

Left ventricle to right ventricle size discrepancy in the fetus: the presence of critical congenital heart disease can be reliably predicted.

BACKGROUND: Prenatal ventricular size discrepancy with disproportionately smaller left ventricle than right ventricle (L-R/VD) can be a marker for important left-sided structural heart disease in the newborn. METHODS: We reviewed the echocardiograms of all fetuses evaluated at our center with L-R/VD from July 1, 2004 to January 1, 2008. RESULTS: Of the 35 fetuses, 20 (57%) had critical arch obstruction and underwent neonatal intervention (group 1); 15 (43%) did not require newborn intervention (group 2). Ratios comparing left with right heart structures were significantly lower in group 1 fetuses compared with group 2 fetuses. Aortic arch measurement

Right ventricular performance in the fetus with hypoplastic left heart syndrome.

BACKGROUND: In the fetus with hypoplastic left heart syndrome (HLHS), the single right ventricle (RV) pumps the entire cardiac output in utero. By investigating RV performance in utero, we sought to determine the inherent capabilities of a single RV before the increased metabolic demands of postnatal life and surgical palliation. In addition, we sought to determine whether the presence or absence of a left ventricular cavity impacts on RV performance in fetal life. METHODS: Between November 2004 and December 2006, Doppler flow-derived measures of ventricular performance were obtained with echocardiography in 76 fetuses with normal cardiovascular system and in 48 age-matched fetuses with HLHS from 17 weeks until 40 weeks of gestation. The myocardial performance index, ventricular ejection force, and cardiac output were determined for both groups and compared using unpaired Student's t tests and regression analysis. RESULTS: In fetuses with HLHS, cardiac output was diminished by 20%, RV ejection force was elevated, and RV myocardial performance index was elevated compared with those of normal fetuses. The presence of a left ventricular cavity did not impact on RV performance in utero. CONCLUSIONS: Fetuses with HLHS have preserved systolic performance but impaired diastolic performance compared with normal fetuses. The heart of a fetus with HLHS is less efficient than the normal heart in that ejection force of the RV is increased, but overall delivery of cardiac output is lower than normal. We conclude that patients with HLHS have inherent limitations in cardiac performance even before birth.

The twin-twin transfusion syndrome: spectrum of cardiovascular abnormality and development of a cardiovascular score to assess severity of disease.

OBJECTIVE: Current means of grading twin-twin transfusion syndrome does not characterize cardiovascular aspects adequately. We sought to develop a score that describes the magnitude of cardiovascular severity in twin-twin transfusion syndrome. STUDY DESIGN: Fetal echocardiograms of 150 monochorionic/diamniotic twins were reviewed. Blinded to Quintero stage, we applied a cardiovascular score to each twin set and compared it to the Quintero grade. The score is a composite of variables that include ventricular hypertrophy, dilation, function, valve regurgitation, great artery size, and diastolic properties in the recipient and umbilical artery flow in the donor. Doppler indices of vascular and ventricular function were measured. RESULTS: Mean age was 21 +/- 3 weeks. Discrepancy was noted in degree of severity between Quintero and cardiovascular stages. The score correlated well with myocardial performance index of the recipient right ventricle (r2 = .65). CONCLUSION: We describe the spectrum of cardiovascular abnormalities that are seen in twin-twin transfusion syndrome and propose a scoring system for assessment of severity.

Heterotaxy syndrome with functional single ventricle: does prenatal diagnosis improve survival?

BACKGROUND: Despite improved outcome for many single ventricle lesions, staged reconstruction for heterotaxy syndrome with a functional single ventricle continues to have a high mortality. Prenatal identification of heterotaxy syndrome may improve long-term survival. METHODS: Our database was reviewed from January 1996 to December 2004 for patients with heterotaxy syndrome. Assessment was made for prenatal diagnosis and echocardiographic characteristics of heterotaxy syndrome. We sought to assess the accuracy of fetal echocardiography in the diagnosis of heterotaxy syndrome and determine whether prenatal diagnosis and other risk factors have an impact on survival in patients with heterotaxy syndrome. RESULTS: Of 81 patients that met criteria, 43 (53%) had prenatal diagnosis. Prenatal diagnosis had high specificity and positive predictive value for all findings but had low sensitivity for anomalous pulmonary veins. Among the 70 patients born alive, survival was 60% with median follow-up of 51.4 months (range, 6.5 to 109.7 months). Prenatal diagnosis did not improve survival (p = 0.09). None of the 11 patients with complete heart block (CHB) survived past 3 months of age. Two patients underwent heart transplantation as their first intervention and have survived. CHB and anomalous pulmonary venous connection were associated with shorter duration of survival. CONCLUSIONS: Prenatal diagnosis of heterotaxy syndrome does not improve survival in patients who undergo single ventricle reconstruction. The most potent risk factors for poor outcome (CHB, anomalous pulmonary veins) are likely not impacted by identification in utero. In light of the poor outcome, cardiac transplantation as an initial therapy may be a viable option for some patients.

Preliminary investigations into a new method of functional assessment of the fetal heart using a novel application of 'real-time' cardiac magnetic resonance imaging.

OBJECTIVES: Because of quantitative echocardiographic limitations of fetal ventricular volumes as well as poor windows, we sought to determine if real-time magnetic resonance imaging (MRI) could be used. METHODS: Real-time, functional, true fast imaging with steady-state precession, cardiac MRI was performed on 2 fetuses (one with hypoplastic left heart syndrome and one with ductal constriction). Fetal echocardiography was performed and cardiac index by Doppler was used to validate volume measures by MRI. RESULTS: This technique was able to visualize the beating heart and assess ventricular volumes. Cardiac index and assessment of right ventricular hypertrophy and dilation by echocardiography were consistent with the ventricular volumes and right ventricular hypertrophy obtained by cardiac MRI. CONCLUSION: Real-time, functional fetal cardiac MRI is possible and can be used to quantitatively assess ventricular volumes and cardiac index in utero.