Sinai C. Zyblewski

Comparison of Norwood Shunt Types: Do the Outcomes Differ 6 Years Later?

BACKGROUND A modification to the Norwood procedure involving a right ventricle-to-pulmonary artery (RV-PA) shunt may improve early postoperative outcomes. Concerns remain about the effect of the right ventriculotomy required with this shunt on long-term ventricular function. METHODS Between January 2000 and April 2005, 76 patients underwent the Norwood procedure, 35 with a modified Blalock-Taussig shunt (mBTS) and 41 with a RV-PA shunt. Patients were monitored until death or September 1, 2009, with an average follow-up of 6.8 years. Cardiac catheterization, echocardiograms, perioperative Fontan courses, and need for cardiac transplantation were compared between groups. RESULTS Cumulative survival was 63% (22 of 35) in the mBTS group vs 78% (32 of 41) in the RV-PA group (p = 0.14). Pre-Fontan echocardiography revealed poorer ventricular function in RV-PA patients (p = 0.03). Cardiac transplantation was required in 6 of 32 (19%) patients with a prior RV-PA shunt vs 1 of 23 (4%) in the mBTS group (p = 0.06). This results in an almost identical cumulative transplant-free survival between groups; 60% (21 of 35) in the mBTS group and 63% (26 of 41) in the RV-PA group (p = 0.95). CONCLUSIONS Neither shunt offers a clear survival advantage through an average follow-up of 6.8 years. The RV-PA shunt results in impaired late ventricular function that may result in an increased need for cardiac transplantation.

Variation in Feeding Practices following the Norwood Procedure

OBJECTIVES To assess variation in feeding practice at hospital discharge after the Norwood procedure, factors associated with tube feeding, and associations among site, feeding mode, and growth before stage II. STUDY DESIGN From May 2005 to July 2008, 555 subjects from 15 centers were enrolled in the Pediatric Heart Network Single Ventricle Reconstruction Trial; 432 survivors with feeding data at hospital discharge after the Norwood procedure were analyzed. RESULTS Demographic and clinical variables were compared among 4 feeding modes: oral only (n = 140), oral/tube (n = 195), nasogastric tube (N-tube) only (n = 40), and gastrostomy tube (G-tube) only (n = 57). There was significant variation in feeding mode among sites (oral only 0%-81% and G-tube only 0%-56%, P < .01). After adjusting for site, multivariable modeling showed G-tube feeding at discharge was associated with longer hospitalization, and N-tube feeding was associated with greater number of discharge medications (R(2) = 0.65, P < .01). After adjusting for site, mean pre-stage II weight-for-age z-score was significantly higher in the oral-only group (-1.4) vs the N-tube-only (-2.2) and G-tube-only (-2.1) groups (P = .04 and .02, respectively). CONCLUSIONS Feeding mode at hospital discharge after the Norwood procedure varied among sites. Prolonged hospitalization and greater number of medications at the time of discharge were associated with tube feeding. Infants exclusively fed orally had a higher weight-for-age z score pre-stage II than those fed exclusively by tube. Exploring strategies to prevent morbidities and promote oral feeding in this highest risk population is warranted.

Initial Experience With a Miniaturized Multiplane Transesophageal Probe in Small Infants Undergoing Cardiac Operations

PURPOSE There has been reluctance to use intraoperative transesophageal echocardiography (TEE) in small infants. We assessed the utility and safety of a new miniaturized multiplane micro-TEE probe in small infants undergoing cardiac operations. DESCRIPTION Hemodynamic and ventilation variables were prospectively recorded before and after micro-TEE insertion and removal in infants weighing 5 kg or less undergoing cardiac operations. EVALUATION The study included 42 patients with a mean weight of 3.6 +/- 0.9 kg (range, 1.7 to 5 kg). All probe insertions were successful. There were no complications or clinically significant changes in hemodynamic or ventilation variables. Information provided by TEE resulted in surgical revision in 6 of the 42 patients. CONCLUSIONS The micro-TEE provides high quality, useful diagnostic images without hemodynamic or ventilation compromise in small infants undergoing cardiac operations. This advance is important with the growing trend towards complete repair of complex structural heart disease in small infants.

Longitudinal Assessment of Growth in Hypoplastic Left Heart Syndrome: Results From the Single Ventricle Reconstruction Trial

Background We sought to characterize growth between birth and age 3 years in infants with hypoplastic left heart syndrome who underwent the Norwood procedure. Methods and Results We performed a secondary analysis using the Single Ventricle Reconstruction Trial database after excluding patients <37 weeks gestation (N=498). We determined length‐for‐age z score (LAZ) and weight‐for‐age z score (WAZ) at birth and age 3 years and change in WAZ over 4 clinically relevant time periods. We identified correlates of change in WAZ and LAZ using multivariable linear regression with bootstrapping. Mean WAZ and LAZ were below average relative to the general population at birth (P<0.001, P=0.05, respectively) and age 3 years (P<0.001 each). The largest decrease in WAZ occurred between birth and Norwood discharge; the greatest gain occurred between stage II and 14 months. At age 3 years, WAZ and LAZ were <−2 in 6% and 18%, respectively. Factors associated with change in WAZ differed among time periods. Shunt type was associated with change in WAZ only in the Norwood discharge to stage II period; subjects with a Blalock‐Taussig shunt had a greater decline in WAZ than those with a right ventricle‐pulmonary artery shunt (P=0.002). Conclusions WAZ changed over time and the predictors of change in WAZ varied among time periods. By age 3 years, subjects remained small and three times as many children were short as were underweight (>2 SD below normal). Failure to find consistent risk factors supports the strategy of tailoring nutritional therapies to patient‐ and stage‐specific targets. Clinical Trial Registration URL: http://clinicaltrials.gov/. Unique identifier: NCT00115934.

Intraoperative Steroid Use and Outcomes Following the Norwood Procedure: An Analysis of the Pediatric Heart Network's Public Database.

Objective: Data supporting the use of perioperative steroids during cardiac surgery are conflicting, and most pediatric studies have been limited by small sample sizes and/or diverse cardiac diagnoses. The objective of this study was to determine if intraoperative steroid administration improved outcomes following the Norwood procedure. Design: A retrospective analysis was performed on the 549 neonates who underwent a Norwood procedure in the publicly available datasets from the Pediatric Heart Network’s Single Ventricle Reconstruction trial. Groups were compared to determine if outcomes differed between intraoperative steroid recipients (n = 498, 91%) and nonrecipients (n = 51, 9%). Setting: Fifteen North American centers. Subjects: Infants enrolled in the Single Ventricle Reconstruction trial. Interventions: None. Measurements and Main Results: Baseline characteristics and intraoperative variables were similar between groups with the exception of a shorter duration of cross clamp and cardiopulmonary bypass time in the group that received steroids. Subjects who did not receive intraoperative steroids had improved hospital survival (94% vs 83%, p = 0.03) but longer ICU stays (16 d; interquartile range, 12–33 vs 14 d; interquartile range, 9–28; p = 0.04) and hospital stays (29 d; interquartile range, 21–50 vs 23 d; interquartile range, 15–40; p = 0.01) than steroid recipients. In multivariate analysis, lengths of stay associations were no longer significant, but hospital survival trended toward favoring the nonsteroid group with an odds ratio of 3.52 (95% CI, 0.98–12.64; p = 0.054). Conclusions: In the large multicentered Single Ventricle Reconstruction trial, there was widespread use of intraoperative steroids. Intraoperative steroid administration was not associated with an improvement in outcomes and may be associated with a reduction in hospital survival in neonates undergoing the Norwood procedure. This study highlights the need for a randomized control trial.

Clinico-morphological correlations in the categorization of holes between the ventricles

Controversy still exists in the categorization of holes between the ventricles, although they are the most common congenital cardiac malformation. Advanced imaging techniques such as three-dimensional echocardiography and computed tomographic angiography offer superb anatomical details of these defects. In this review, we have sought to collate the features highlighted in different categorizations and identify their similarities, but also emphasize their differences. We hope that an analysis of this type, now achievable during life, using advanced imaging, might lead to the appearance of a unified system for diagnosis and description of holes between the ventricles.

Randomized Clinical Trial of Preoperative Feeding to Evaluate Intestinal Barrier Function in Neonates Requiring Cardiac Surgery.

OBJECTIVES To evaluate intestinal barrier function in neonates undergoing cardiac surgery using lactulose/mannitol (L/M) ratio measurements, and to determine correlations with early breast milk feeding. STUDY DESIGN This was a single-center, prospective, randomized pilot study of 27 term-born neonates (≥ 37 weeks gestation) requiring cardiac surgery who were randomized to 1 of 2 preoperative feeding groups: nil per os (NPO) or trophic (10 mL/kg/day) breast milk feeds. At 3 time points (preoperative [preop], postoperative [postop] day 7, and postop day 14), subjects were administered an oral L/M solution, after which urine L/M ratios were measured using gas chromatography, with higher ratios indicative of increased intestinal permeability. Trends over time in the mean urine L/M ratios for each group were estimated using a general linear mixed model. RESULTS There were no adverse events related to preoperative trophic feeding. In the NPO group (n = 13), the mean urine L/M ratio was 0.06 at preop, 0.12 at postop day 7, and 0.17 at postop day 14. In the trophic breast milk feeds group (n = 14), the mean urine L/M ratio was 0.09 at preop, 0.19 at postop day 7, and 0.15 at postop day 14. In both groups, L/M ratios were significantly higher at postop day 7 and postop day 14 compared with preop (P < .05). CONCLUSION Neonates have increased intestinal permeability after cardiac surgery extending to at least postop day 14. This pilot study was not powered to detect differences in benefit or adverse events comparing the NPO and trophic breast milk feeds groups. Further studies to identify mechanisms of intestinal injury and therapeutic interventions are warranted. TRIAL REGISTRATION Registered with ClinicalTrials.gov: NCT01475357.

Dysphagia in infants with single ventricle anatomy following stage 1 palliation: Physiologic correlates and response to treatment

BACKGROUND Deficits in swallowing physiology are a leading morbidity for infants with functional single ventricles and systemic outflow tract obstruction following stage 1 palliation. Despite the high prevalence of this condition, the underlying deficits that cause this post-operative impairment remain poorly understood. OBJECTIVE Identify the physiologic correlates of dysphagia in infants with functional single ventricles and systemic outflow tract obstruction following stage 1 palliative surgery. METHODS Postoperative fiberoptic laryngoscopies and videofluoroscopic swallow studies (VFSS) were conducted sequentially on infants with functional single ventricles following stage 1 palliative surgery. Infants were dichotomized as having normal or impaired laryngeal function based on laryngoscopy findings. VFSS were evaluated frame-by-frame using a scale that quantifies performance within 11 components of swallowing physiology. Physiologic attributes within each component were categorized as high functioning or low functioning based on their ability to support milk ingestion without bolus airway entry. RESULTS Thirty-six infants (25 male) were included in the investigation. Twenty-four underwent the Norwood procedure and twelve underwent the Hybrid procedure. Low function physiologic patterns were observed within multiple swallowing components during the ingestion of thin barium as characterized by ≥4 sucks per swallow (36%), initiation of pharyngeal swallow below the level of the valleculae (83%), and incomplete late laryngeal vestibular closure (56%) at the height of the swallow. Swallowing deficits contributed to aspiration in 50% of infants. Although nectar thick liquids reduced the rate of aspiration (P = .006), aspiration rates remained high (27%). No differences in rates of penetration or aspiration were observed between infants with normal and impaired laryngeal function. CONCLUSIONS Deficits in swallowing physiology contribute to penetration and aspiration following stage 1 palliation among infants with normal and impaired laryngeal function. Although thickened liquids may improve airway protection for select infants, they may inhibit their ability to extract the bolus and meet nutritional needs.

Preoperative Feeding Neonates With Cardiac Disease

Background: The potential for necrotizing enterocolitis (NEC) in neonates requiring cardiac surgery has contributed largely to wide feeding practice variations and a hesitation to initiate enteral feeding during the preoperative period, specifically those patients with hypoplastic left heart syndrome. Methods: A retrospective chart review of neonates undergoing cardiac surgery at a single institution between July 2011 and July 2013 was performed. The primary objective of this study was to determine if preoperative feeding was associated with NEC in neonates requiring cardiac surgery. Univariable and multivariable analyses were performed to evaluate the relationship between preoperative feeding and NEC. Secondary outcomes including growth failure, total ventilator days, total length of stay, and tube-assisted feeds at discharge were analyzed. Results: One hundred thirty consecutive neonates who required cardiac surgery were included in the analysis. Preoperative feeding occurred in 61% (n = 79). The overall prevalence of NEC was 9% (12/130), including three neonates with surgical NEC. There was no difference in the prevalence of NEC between the preoperative feeding and nil per os (NPO) groups. Preoperative NPO status was associated with longer ventilator-dependent days (P = .01) but was not associated with worsened growth failure, longer length of stay, or increased prevalence of tube-assisted feeds at discharge. Conclusion: In this study cohort, preoperative feeding was associated with a low prevalence of NEC. Larger prospective studies evaluating the safety and benefits of preoperative feeding in cardiac neonates are warranted.

Assessment of Growth 6 Years after the Norwood Procedure.

&NA; At 6 years of age, patients with hypoplastic left heart syndrome had mean age‐adjusted z‐scores for weight and height below the normative population, and body mass index was similar to the normative population. Males had the greatest increase in z‐scores for body mass index. Trial registration ClinicalTrials.gov: NCT00115934.