Jay D. Pruetz

Differential branch pulmonary artery growth after the Norwood procedure with right ventricle–pulmonary artery conduit versus modified Blalock–Taussig shunt in hypoplastic left heart syndrome

OBJECTIVES The Norwood procedure with right ventricle-pulmonary artery conduit is thought to improve postoperative hemodynamics in hypoplastic left heart syndrome, but its effects on pulmonary artery growth are unknown. This study evaluated pulmonary artery growth after the Norwood procedure in patients with a right ventricle-pulmonary artery conduit as compared with patients with a modified Blalock-Taussig shunt. METHODS A total of 159 patients at our institution underwent the Norwood procedure between January 2000 and September 2005. Patients were divided into group A or B if they had a modified Blalock-Taussig shunt (n = 103) or a right ventricle-pulmonary artery conduit (n = 56). Angiograms from the pre-Glenn catheterizations were used to measure pulmonary artery size and assess shunt stenosis (n = 64). RESULTS Fifty-five (53.4%) patients in group A versus 40 (71.4%) in group B underwent Glenn surgery. Group B patients often required an additional shunt (modified Blalock-Taussig) before the Glenn procedure because of hypoxemia (8/40 vs 1/55; P = .004). Branch pulmonary artery growth was better in group B patients who did not require an additional shunt (Nakata index 212 vs 169 mm(2)/m(2); P = .004) and more balanced than in group A (right pulmonary artery/left pulmonary artery ratio = 1.02 vs 1.39; P = .001) as a result of greater left pulmonary artery size (29 vs 19 mm(2); P = .001). However, group B experienced more shunt stenosis (8/32 vs 2/32; P = .001), underwent the Glenn operation earlier (192 vs 246 days; P = .03), and had central pulmonary artery hypoplasia develop more often than group A patients (25/32 vs 14/32; P = .01). CONCLUSION The Norwood procedure with a right ventricle-pulmonary artery conduit promotes better distal left pulmonary artery growth resulting in more balanced branch pulmonary artery size, but central pulmonary artery hypoplasia occurs more often. Early right ventricle-pulmonary artery conduit stenosis also increases the need for additional shunting or early Glenn surgery.

Outcomes and Predictors of Perinatal Mortality in Fetuses With Ebstein Anomaly or Tricuspid Valve Dysplasia in the Current Era A Multicenter Study

Background— Ebstein anomaly and tricuspid valve dysplasia are rare congenital tricuspid valve malformations associated with high perinatal mortality. The literature consists of small, single-center case series spanning several decades. We performed a multicenter study to assess the outcomes and factors associated with mortality after fetal diagnosis in the current era. Methods and Results— Fetuses diagnosed with Ebstein anomaly and tricuspid valve dysplasia from 2005 to 2011 were included from 23 centers. The primary outcome was perinatal mortality, defined as fetal demise or death before neonatal discharge. Of 243 fetuses diagnosed at a mean gestational age of 27±6 weeks, there were 11 lost to follow-up (5%), 15 terminations (6%), and 41 demises (17%). In the live-born cohort of 176 live-born patients, 56 (32%) died before discharge, yielding an overall perinatal mortality of 45%. Independent predictors of mortality at the time of diagnosis were gestational age <32 weeks (odds ratio, 8.6; 95% confidence interval, 3.5–21.0; P<0.001), tricuspid valve annulus diameter z-score (odds ratio, 1.3; 95% confidence interval, 1.1–1.5; P<0.001), pulmonary regurgitation (odds ratio, 2.9; 95% confidence interval, 1.4–6.2; P<0.001), and a pericardial effusion (odds ratio, 2.5; 95% confidence interval, 1.1–6.0; P=0.04). Nonsurvivors were more likely to have pulmonary regurgitation at any gestational age (61% versus 34%; P<0.001), and lower gestational age and weight at birth (35 versus 37 weeks; 2.5 versus 3.0 kg; both P<0.001). Conclusion— In this large, contemporary series of fetuses with Ebstein anomaly and tricuspid valve dysplasia, perinatal mortality remained high. Fetuses with pulmonary regurgitation, indicating circular shunt physiology, are a high-risk cohort and may benefit from more innovative therapeutic approaches to improve survival.

Outcomes of critical congenital heart disease requiring emergent neonatal cardiac intervention.

The aim of this study was to evaluate outcomes for neonates with critical congenital heart disease (CHD) requiring emergent neonatal cardiac intervention (ENCI).

Prenatal diagnosis of congenital heart disease: impact of mode of delivery on neonatal outcome

We sought to evaluate the impact of mode of delivery (MOD) on early outcome for neonates diagnosed prenatally with major forms of congenital heart disease (CHD).

Preclinical Testing and Optimization of a Novel Fetal Micropacemaker

Yaniv Bar-Cohen, MD, FHRS, Gerald E. Loeb, MD, Jay D. Pruetz, MD, Michael J. Silka, MD, Catalina Guerra, DVM, Adriana N. Vest, BE, Li Zhou, MS, Ramen H. Chmait, MD From the Division of Cardiology, Children’s Hospital Los Angeles; and Keck School of Medicine, University of Southern California, Los Angeles, CA, Department of Biomedical Engineering, University of Southern California, Los Angeles, California, C.W. Steers Biological Resources Center, Los Angeles Biomedical Research Institute, Harbor–University of California, Los Angeles, Torrance, California, and Department of Obstetrics and Gynecology, Keck School of Medicine, University of Southern California, Los Angeles, California.

Design and Testing of a Percutaneously Implantable Fetal Pacemaker

We are developing a cardiac pacemaker with a small, cylindrical shape that permits percutaneous implantation into a fetus to treat complete heart block and consequent hydrops fetalis, which can otherwise be fatal. The device uses off-the-shelf components including a rechargeable lithium cell and a highly efficient relaxation oscillator encapsulated in epoxy and glass. A corkscrew electrode made from activated iridium can be screwed into the myocardium, followed by release of the pacemaker and a short, flexible lead entirely within the chest of the fetus to avoid dislodgement from fetal movement. Acute tests in adult rabbits demonstrated the range of electrical parameters required for successful pacing and the feasibility of successfully implanting the device percutaneously under ultrasonic imaging guidance. The lithium cell can be recharged inductively as needed, as indicated by a small decline in the pulsing rate.

Twin–twin transfusion syndrome treated with laser surgery: postnatal prevalence of congenital heart disease in surviving recipients and donors

To assess postnatal prevalence of congenital heart disease (CHD) in surviving twins treated for twin–twin transfusion syndrome (TTTS) with laser surgery.

Fetal cardiology: changing the definition of critical heart disease in the newborn

Infants born with congenital heart disease (CHD) may require emergent treatment in the newborn period. These infants are likely to benefit the most from a prenatal diagnosis, which allows for optimal perinatal planning. Several cardiac centers have created guidelines for the management of these high-risk patients with CHD. This paper will review and compare several prenatal CHD classification systems with a particular focus on the most critical forms of CHD in the fetus and newborn. A contemporary definition of critical CHD is one which requires urgent intervention in the first 24 h of life to prevent death. Such cardiac interventions may be not only life saving for the infant but also decrease subsequent morbidity. Critical CHD cases may require delivery at specialized centers that can provide perinatal, obstetric, cardiology and cardiothoracic surgery care. Fetuses diagnosed in mid-gestation require detailed fetal diagnostics and serial monitoring during the prenatal period, in order to assess for ongoing changes and identify progression to a more severe cardiac status. Critical CHD may progress in utero and there is still much to be learned about how to best predict those who will require urgent neonatal interventions. Despite improved therapeutic capabilities, newborns with critical CHD continue to have significant morbidity and mortality due to compromise that begins in the delivery room. Fetal echocardiography is the best way to predict the need for specialized care at birth to improve outcome. Once the diagnosis is made of critical CHD, delivery at the proper time and in appropriate institution with specific care protocols should be initiated. More work needs to be done to better delineate the risk factors for progression of critical CHD and to determine which newborns will require specialized care. The most frequently described forms of critical CHD requiring immediate intervention include hypoplastic left heart syndrome with intact or severely restricted atrial septum, obstructed total anomalous pulmonary venous return and transposition of the great arteries with restrictive atrial septum.

Blood pressure evaluation in children treated with laser surgery for twin-twin transfusion syndrome at 2-year follow-up

OBJECTIVE Twin survivors of twin-twin transfusion syndrome (TTTS) may be at risk for early onset of cardiovascular disease. The aim of this study was to determine prevalence and risk factors for elevated blood pressure (BP) among children treated with selective laser photocoagulation of communicating vessels. STUDY DESIGN Data were prospectively collected from surviving children treated for TTTS with laser surgery from 2008 through 2010. Systolic BP (SBP) and diastolic BP (DBP) were obtained from 91 child survivors at age 24 months (±6 weeks) and evaluated based on age, sex, and height percentile. BP percentiles were calculated for each patient and categorized as normal (<95%) or abnormal (>95%). Clinical variables were evaluated using multilevel regression models to evaluate risk factors for elevated BP. RESULTS BP was categorized as normal in 38% and abnormal in 62% of twin survivors based on percentile for sex, age, and height; a comparable distribution was found for DBP elevation. There were no differences between donor and recipient twins for absolute SBP and DBP or BP classification. In a multivariate analysis, significant risk factors for higher SBP included prematurity (β -0.54; 95% confidence interval [CI], -0.99 to -0.09; P = .02), higher weight percentile (β 0.24; 95% CI, 0.05-0.42; P = .01), and presence of cardiac disease (β 0.50; 95% CI, 0.10-0.89; P = .01). Prematurity was also a significant risk for abnormal DBP (odds ratio, 0.89; 95% CI, 0.80-1.00; P = .05). CONCLUSION Child survivors of TTTS had elevated SBP and DBP measurements at 2 years of age, with no differences seen between former donor and recipient twins. Prematurity may be a risk factor for elevated BP measurements in this population. Future studies are warranted to ascertain whether these cardiovascular findings persist over time.

Complete Right Heart Flow Reversal Pathognomonic Recipient Twin Circular Shunt in Twin-Twin Transfusion Syndrome

Although the pathophysiologic mechanism of twin-twin transfusion syndrome (TTTS) remains incompletely understood, the process appears to involve abnormal vascular communications within the placenta, leading to characteristic hemodynamic changes in the recipient fetus. The recipient twin may have progressive volume and pressure overload, congestive heart failure, and hydrops. Recipient twin echocardiographic findings, which typically include valvar regurgitation/stenosis, ventricular hypertrophy, and diastolic/systolic dysfunction, tend to occur predominantly in the right heart, with relative sparing of the left. We describe a case of complete right heart flow reversal and preserved left ventricle (LV) function in a recipient twin, with complete resolution and normalization 1 month after successful selective fetoscopic laser photocoagulation (SFLP) of communicating vessels. We suggest that the circular shunt seen preoperatively through the right heart of the recipient twin represents a pathognomonic finding for TTTS. We speculate that the right ventricle (RV) may be particularly sensitive to the increase in afterload encountered by recipient twins in TTTS.