Stage I palliation for hypoplastic left heart syndrome: Norwood versus Sano modification

Pre- and post-operative cardiovascular CT in Stage I single ventricle palliation

OBJECTIVES

The aim of this study is to describe clinical utility of low dose cardiac computed tomography (CT) in the evaluation of single ventricle physiology before and after Stage I palliation.

BACKGROUND

Despite the increased utilization of CT imaging and advancement of CT technology, there are limited studies describing the routine clinical use of cardiac CT and radiation dose parameters in the single ventricle Stage I palliation.

METHODS

This single center, retrospective study included 57 infants with single ventricle physiology who underwent cardiac CT scans between January 1, 2016 and November 30, 2020. Patients' demographic information, diagnosis, indication, total dose length product (DLP), computed tomographic dose index volume (CTDIvol), cardiac CT findings and intraoperative or intraprocedural findings were reviewed. Estimated effective radiation dose was calculated using a previously published conversion rate.

RESULTS

The studies were performed using different generations of CT scanners over the 4 years period: Somatom AS 128, Somatom definition edge, Somatom Force (Siemens Medical Solutions). The studies performed with dual source scanner with prospective gated technique have lower radiation dose exposure with median effective radiation dose of 0.32 mSv.

CONCLUSION

Pre- and post-operative cardiovascular CT in Stage I single ventricle palliation using newer generation scanners with prospective gated technique can be done with minimal radiation exposure and good image quality. Cardiac CT is a powerful imaging modality for better management planning in this group of patients.

Acute kidney injury is associated with subsequent infection in neonates after the Norwood procedure: a retrospective chart review

BACKGROUND

Acute kidney injury (AKI) and infection are common complications after pediatric cardiac surgery. No pediatric study has evaluated for an association between postoperative AKI and infection. The objective of this study was to determine if AKI in neonates after cardiopulmonary bypass was associated with the development of a postoperative infection.

METHODS

We performed a single center retrospective chart review from January 2009 to December 2015 of neonates (age ≤ 30 days) undergoing the Norwood procedure. AKI was defined by the modified neonatal Kidney Disease Improving Global outcomes serum creatinine criteria using (1) measured serum creatinine and (2) creatinine corrected for fluid balance on postoperative days 1-4. Infection, (culture positive or presumed), must have occurred after a diagnosis of AKI and within 60 days of surgery.

RESULTS

Ninety-five patients were included, of which postoperative infection occurred in 42 (44%). AKI occurred in 38 (40%) and 42 (44%) patients by measured serum creatinine and fluid overload corrected creatinine, respectively, and was most commonly diagnosed on postoperative day 2. The median time to infection from the time of surgery and AKI was 7 days (IQR 5-14 days) and 6 days (IQR 3-13 days), respectively. After adjusting for confounders, the odds of a postoperative infection were 3.64 times greater in patients with fluid corrected AKI (95% CI, 1.36-9.75; p = 0.01).

CONCLUSIONS

Fluid corrected AKI was independently associated with the development of a postoperative infection. These findings support the notion that AKI is an immunosuppressed state that increases the risk of infection.

CT for Assessment of Thrombosis and Pulmonary Embolism in Multiple Stages of Single-Ventricle Palliation: Challenges and Suggested Protocols

The total cavopulmonary connection (TCPC), or Fontan procedure, diverts systemic venous blood directly into the pulmonary arteries and is the palliative surgery of choice for patients with a wide variety of congenital heart diseases with single-ventricle physiologic characteristics. Pulmonary embolism and thrombosis are known complications and are among the major causes of morbidity and mortality in patients after TCPC. Magnetic resonance (MR) imaging is usually performed for postoperative evaluation of patients after single-ventricle repair; however, screening for thrombosis or embolism with MR imaging is not always feasible because of the emergent nature of the clinical presentation or because of artifacts from metallic devices or coils. Computed tomographic (CT) angiography is an effective method for diagnosing pulmonary embolism in children. However, because of altered hemodynamics after single-ventricle palliation, there are unique challenges in achieving optimal opacification of the pulmonary arteries and Fontan circuit that can result in nondiagnostic CT angiographic studies or erroneous image interpretation. Radiologists should be familiar with the multiple stages of single-ventricle palliation, understand the technique for performing pulmonary CT angiography at each stage, and recognize common pitfalls in obtaining and interpreting pulmonary CT angiographic images in patients who have undergone single-ventricle repair. Online supplemental material is available for this article. (©)RSNA, 2016.

Clinical findings in right ventricular noncompaction in hypoplastic left heart syndrome

BACKGROUND

Noncompaction is a poorly understood form of cardiomyopathy that typically affects the left ventricle and may be associated with congenital heart disease. Right ventricular noncompaction (RVNC) may occur when the left ventricle is affected but is rarely seen in isolation. RVNC may have clinical significance affecting surgical and long-term outcomes. We describe the diagnosis and clinical course in three patients at our institution.

METHODS

We performed a retrospective review of patients diagnosed with RVNC over a 12-month period at our institution and reviewed their imaging and clinical course.

RESULTS

Three patients were identified. All had diagnosis of RVNC by echocardiography (echo) made on postnatal imaging which reviewed degree of trabeculation, and noncompaction-to-compaction ratio of the myocardium. Patient A was a neonate with hypoplastic left heart syndrome (HLHS) who underwent a Norwood operation with Sano modification. Her postoperative course was notable for low-normal RV function. She returned with a pericardial effusion warranting immediate pericardiocentesis. She continued to have effusions, which were medically managed. She was subsequently found to have an RV apical pseudoaneurysm, which required surgical resection. Patient B was a neonate with HLHS who had a Norwood operation with Sano modification. She had low-normal RV function on echo. She required medical management for pericardial effusion. Patient C was a neonate with HLHS who also underwent a Norwood operation with Sano modification. His postoperative course was notable for elevated serum brain natriuretic peptide, which was treated with digoxin.

CONCLUSION

RVNC is a rare diagnosis with limited known clinical impact. One of these patients had a very rare complication after pericardiocentesis (pseudoaneurysm) that may have been related to the RVNC. Our understanding of this disease process is limited and requires additional investigation, but emphasizes the importance of appropriate diagnosis to allow for timely follow-up and counseling for this unique population.

Mathematical Analysis and Physical Profile of Blalock-Taussig Shunt and Sano Modification Procedure in Hypoplastic Left Heart Syndrome: Review of the Literature and Implications for the Anesthesiologist

The first stage of surgical treatment for hypoplastic left heart syndrome (HLHS) includes the creation of artificial systemic-to-pulmonary connections to provide pulmonary blood flow. The modified Blalock-Taussig (mBT) shunt has been the technique of choice for this procedure; however, a right ventricle-pulmonary artery (RV-PA) shunt has been introduced into clinical practice with encouraging but still conflicting outcomes when compared with the mBT shunt. The aim of this study is to explore mathematical modeling as a tool for describing physical profiles that could assist the surgical team in predicting complications related to stenosis and malfunction of grafts in an attempt to find correlations with clinical outcomes from clinical studies that compared both surgical techniques and to assist the anesthesiologist in making decisions to manage patients with this complex cardiac anatomy. Mathematical modeling to display the physical characteristics of the chosen surgical shunt is a valuable tool to predict flow patterns, shear stress, and rate distribution as well as energetic performance at the graft level and relative to ventricular efficiency. Such predictions will enable the surgical team to refine the technique so that hemodynamic complications be anticipated and prevented, and are also important for perioperative management by the anesthesia team.

Long-term progression and survival following Norwood Single Ventricle Reconstruction

PURPOSE OF REVIEW

Much data exist concerning Norwood discharge mortality. Less is known about late survival. Examining the available data in light of the Single Ventricle Reconstruction trial is insightful as focus shifts toward long-term survival.

RECENT FINDINGS

Data from 2000 to 2001 demonstrated approximately 40-50% 10-year survival, 30-40% or less between 10 and 15 years. The shape of the curves was characteristic; the majority of deaths within the first year, followed by a late constant phase. Publications from 2001 to 2005 suggested that various combinations of technical and perioperative modifications allowed hospital discharge survivals as high as 90-94%. As results matured (2005-2010) a consistent message was that, although the shape of the newer curves was similar (highest hazard in the first 1 year), higher hospital survival shifted the later phase to yield better long-term survival (70-85% between 5 and 10 years). Some emphasized right ventricle-based shunts as a 'cause' of improving results. Since 2010, the Single Ventricle Reconstruction trial has matured and has increasingly shifted opinion away from the right ventricle shunt as a 'cause' of improved results. The survival of the right ventricle shunt group is slightly higher at 3 years, but the 1-year statistical significance has been lost and the two groups converge. As the Single Ventricle Reconstruction study was based on the interaction between randomized shunt and survival, the secondary and other endpoint analyses must be cautiously considered.

SUMMARY

The current English-language literature suggests a 60-80% 5-10 year survival expectation. The shape of the survival curve remains; the highest hazard remains the first year before a later, stable phase is reached. Rather than a 'magic bullet' theory surrounding one technique or practice, centers have differentially adopted various combinations to optimize Norwood survival. Optimizing interstage I survival is a challenge to further increase the percentage of patients reaching the late, stable phase.

Trends in paediatric, neonatal, and adult cardiology publications over the past 10 years

OBJECTIVE

Medline classifies publications as clinical trials, randomised control trials, meta-analyses, practice guidelines, reviews, case reports, editorials, and letters. We tested the hypothesis that cardiology-related publications have increased with a shift in the type of publications over the past 10 years by age category.

METHODS

To retrieve from Medline the cardiology articles, we used the keyword "heart disease", but limited the search to articles in English from 2000 to 2009. We repeated the search using one limit according to the publication type and using age tags. We used regression analysis to determine the effect of the year of publication on the number of publications of each type.

RESULTS

During the 10-year period, Medline registered 152,849 cardiology articles, doubling from 10,452 in 2000 to 20,841 in 2009, of which 8.5% were tagged as both paediatric and adult. There was a linear increase in the number over the study period in the total number of publications and in all categories, except for practice guidelines. There was almost a twofold increase in adult and neonatal articles, but ∼ 70% in paediatric articles. The rate of increase was 66% for randomised control trials, 73% for clinical trials, 124% for meta-analyses, 117% for editorials, 36% for reviews, and 103% for case reports. Practice guidelines remained very low, increasing significantly for paediatric and neonatal articles.

CONCLUSIONS

There was a substantial increase in cardiology articles over the past 10 years, being greater for adult and neonatal articles compared with paediatric articles. The increase varied according to the type of article.

Contemporary management of pulmonary and systemic circulations after the Norwood procedure

Hypoplastic left heart syndrome remains one of the most challenging pathologies in pediatric cardiac surgery. The surgical techniques, and anesthetic and intensive care management, have evolved over the last decades, which has resulted in improved outcomes. A central component in the postoperative management of hypoplastic left heart syndrome patients is to achieve an optimal balance between the pulmonary and systemic circulations. This article discusses the contemporary postoperative management of pulmonary and systemic circulations in detail.

Palliative procedures for congenital heart defects

Although total repair of some congenital heart defects is possible in young children, palliative procedures still play an important role in relieving patients' symptoms, particularly in emergent settings, when total correction or surgical repair is not available. However, the concepts and taxonomies of the palliative procedures for congenital heart diseases sometimes seem to be ambiguous and confusing for young cardiac surgeons and cardiologists. This article gives a full-scope overview of the concepts, categories, indications, historical developments and clinical outcomes of the palliative procedures for congenital heart defects that have been documented in the literature. In total, there are 21 palliative procedures for the surgical management of congenital heart defects, which can be classified into four categories: firstly, increasing pulmonary artery flow for pulmonary oligaemia (including shunt procedures); secondly, decreasing pulmonary artery flow for pulmonary overcirculation (pulmonary banding and Norwood procedure); thirdly, enhancing intracardiac blood-oxygen mixture for systemic hypoxaemia (atrial septostomy subjected to different techniques); and, finally, other procedures, including congenital mitral or aortic stenosis palliation, coarctation of aorta palliation and hybrid palliative procedures for hypoplastic left heart syndrome. Modified Blalock-Taussig's and Glenn's shunts and pulmonary artery banding represent the pre-eminent palliative procedures for congenital heart defects and have been proven to be satisfactory after long-term clinical application. It seems that there is a growing trend towards the use of interventional techniques with stent deployment as an alternative to the surgical approach.

Congenital cardiac disease in the newborn infant: past, present, and future

Congenital heart defects are the most common of all congenital malformations, with a review of the literature reporting the incidence at 6 to 8 per 1000 live births. The Centers for Disease Control reports cyanotic heart defects occurred in 56.9 per 100,000 live births in the United States in 2005, with higher rates noted when maternal age exceeded 40 years. The incidence of congenital heart disease in premature infants is 12.5 per 1000 live births, excluding isolated patent ductus arteriosus and atrial septal defect. Despite advances in detection and treatment, congenital heart disease accounts for 3% of all infant deaths and 46% of death from congenital malformations. This article discusses the embryology, pathogenesis, clinical presentation, incidence, classifications, and management of congenital heart diseases.