A modifiable valve-sparing pediatric cardiac dissection technique promotes specimen longevity and optimizes advanced image analysis postpathological examination.

This paper illustrates a valve-sparing cardiac dissection technique that keeps the atrioventricular and semilunar valves and other important cardiac structures intact. The technique minimizes disruption in heart specimens, so they remain suitable for teaching, demonstration, and further research. When performed following the perfusion-distension method of fixation, as our group previously described, this technique could optimize the preservation of heart specimens for teaching and digital archiving postdissection.

Bilateral pulmonary artery banding facilitates the systemic ventricular outflow tract growth for biventricular and univentricular repair candidates of complex arch anomaly.

Various surgical approaches address complex heart disease with arch anomalies. Bilateral pulmonary artery banding (bPAB) is a strategy for critically ill patients with complex arch anomalies. Some reports argued the potential effect of bPAB on the growth of the left ventricular outflow tract (LVOT) during inter-stage after bPAB. This study aimed to analyze the LVOT growth for biventricular repair candidates with arch anomaly and systemic ventricular outflow tract (SVOT) for univentricular repair candidates with arch anomaly. This retrospective study analyzed 17 patients undergoing initial bPAB followed by arch repair. The Z-scores of LVOT and SVOT were compared between pre-bPAB and pre-arch repair. Patient characteristics, transthoracic echocardiogram data, and PAB circumferences were reviewed. The diameter of the minimum LVOT for biventricular repair (BVR) candidates, the pulmonary valve (neo-aortic valve, neo-AoV) and the pulmonary trunk (the neo-ascending aorta, neo-AAo) for univentricular repair (UVR) candidates, and the degree of aortic or neo-aortic insufficiency in each candidate was statistically analyzed. 17 patients were divided into the UVR candidates (group U) with 9 patients and the BVR candidates (group B) with 8 patients. In group B, the median value of the Z-score of the minimum LVOT increased from -3.2 (range: - 4.1 ~ - 1.0) at pre-PAB to -2.8 (range: - 3.6 ~ - 0.3) at pre-arch repair with a significant difference (p = 0.012). In group U, the median value of the Z-score of the neo-AoV increased from 0.5 (range: - 1.0 ~ 1.7) at pre-bPAB to 1.2 (range: 0.2 ~ 1.9) at pre-arch repair with a significant difference (p < 0.01). The median value of the Z-score of the neo-AAo was also increased from 3.1 (range: 1.5 ~ 4.6) to 4.3 (range: 3.1 ~ 5.9) with a significant difference (p = 0.028). The growth of the LVOT for BVR candidates and SVOT for UVR candidates during the inter-stage between bPAB and arch repair was observed. These results suggest the potential advantage of bPAB in surgical strategies. Further research is needed to validate these findings and refine surgical approaches.

An effective rehydrating formula for reconditioning dried, irreplaceable heart specimens for teaching.

Formalin-fixed whole heart specimens are essential for studying the anatomy of congenital heart defects. Because of the improvement in diagnostic imaging and treatment, and cultural transition, heart specimens with congenital heart defects have become more and more rare and irreplaceable but are at risk of accidental deterioration through dehydration during long-term storage. In this article, we share our experience in reconditioning our inadvertently dehydrated heart specimens using a simple Formol-Glycerol solution that allowed for rehydration and recovery of such specimens.

OCT-angiography based artificial intelligence-inferred fluorescein angiography for leakage detection in retina [Invited].

Optical coherence tomography angiography (OCTA) covers most functions of fluorescein angiography (FA) when imaging the retina but lacks the ability to depict vascular leakage. Based on OCTA, we developed artificial intelligence-inferred-FA (AI-FA) to delineate leakage in eyes with diabetic retinopathy (DR). Training data of 19,648 still FA images were prepared from FA-photo and videos of 43 DR eyes. AI-FA images were generated using a convolutional neural network. AI-FA images achieved a structural similarity index of 0.91 with corresponding real FA images in DR. The AI-FA generated from OCTA correctly depicted vascular occlusion and associated leakage with enough quality, enabling precise DR diagnosis and treatment planning. A combination of OCT, OCTA, and AI-FA yields more information than real FA with reduced acquisition time without risk of allergic reactions.

Histopathology of resected tissue from repair of anomalous aortic origin of a coronary artery: Potential mechanism of coronary artery compression.

Objective: This study aimed to describe the histomorphologic characteristics of resected (unroofed) common wall tissue from repair of anomalous aortic origin of a coronary artery and to determine whether the histologic features correlate with clinical and imaging findings. Methods: The histology of resected tissue was analyzed and reviewed for the presence of fibrointimal hyperplasia, smooth muscle disarray, mucoid extracellular matrix accumulation, mural fibrosis, and elastic fiber disorganization and fragmentation using hematoxylin and eosin and special stains. Clinical, computed tomography imaging, and surgical data were correlated with the histopathologic findings. Results: Twenty specimens from 20 patients (age range, 7-18 years; 14 males) were analyzed. Anomalous aortic origin of a coronary artery involved the right coronary in 16 (80%), and a slit-like ostium was noted in 18 (90%). By computed tomography imaging, the median proximal coronary artery eccentricity index was 0.4 (range, 0.20-0.90). The median length of intramural course was 8.2 mm (range, 2.6-15.2 mm). The anomalous vessel was determined to be interarterial in 14 patients (93%, 15 had evaluable images). The median distance from a commissure was 2.5 mm above the sinotubular junction (STJ) (range: 2 mm below the STJ-14 mm above the STJ). Prominent histopathologic findings included elastic fiber alterations, mural fibrosis, and smooth muscle disarray. The shared wall of the aorta and intramural coronary artery is more similar to the aorta histologically. Mural fibrosis and elastic fiber abnormalities tended to be more severe in patients >10 years of age at the time of surgery, but this did not reach statistical significance. The extent of vascular changes did not appear to have a clear relationship with the imaging features. Conclusions: The findings confirm the aortic wall-like quality of the intramural segment of the coronary artery and the presence of pathologic alterations in the wall microstructure.

Perfusion-distention fixation of heart specimens: a key step in immortalizing heart specimens for wax infiltration and generating 3D imaging data sets for reconstruction and printed 3D models.

Perfusion-distention fixation by gravity is a fundamental cardiac predissection technique that may be used to preserve the 3D anatomy of a cardiac specimen. The equipment and steps are illustrated, and examples of cardiac specimens preserved in various methods including wet specimens, wax-infiltrated hearts, and 3D-printed models, created after performing this technique, are shown.

Transmitral extraction of a huge left ventricular mural thrombus using a novel mitral leaflet retractor.

A 52-year-old woman with a past history of anterior myocardial infarction 15 years previously was found to have a pedunculated mobile thrombus with a narrow stalk originating from the left ventricle, and a huge laminated mural thrombus. Surgical extraction of the two organized thrombi was successfully performed with transmitral approach using a novel, flexible, self-retained, and reusable leaflet retractor, which was originally developed for exposure of the subvalvular apparatus during mitral valve repair. Excellent access, exposure, and visualization of the left ventricle were achieved by this heart valve retractor and an endoscope for removal of a huge mural thrombus.

Histopathologic Changes After Pulmonary Artery Banding for Retraining of Subpulmonary Left Ventricle.

BACKGROUND: In patients with congenitally corrected transposition of the great arteries (ccTGA) with an intact ventricular septum (IVS) or d-looped transposition of the great arteries (DTGA) with IVS after an atrial switch operation, left ventricular dysfunction often develops after anatomic repair despite previous retraining of the morphologically left ventricle (mLV) by using pulmonary artery banding (PAB). This study examined histopathologic changes in such mLVs. METHODS: Capillary density, myocyte diameter, and interstitial fibrous area in the mLV were retrospectively evaluated in postmortem or explanted heart specimens obtained from patients with ccTGA with IVS or DTGA with IVS after atrial switch operations after PAB for retraining and were compared with those of patients with normal cardiac anatomy, ccTGA with IVS or DTGA with IVS without PAB, and ccTGA or DTGA with high mLV pressure by using generalized estimating equations models. RESULTS: Adjusting for age, capillary density in 4 patients with ccTGA with IVS or DTGA with IVS after PAB was approximately 20% lower than that in 8 patients with normal cardiac anatomy (3149 ± 863/µm2 vs 3978 ± 1206/µm2 [mean, SD]; P = .039), whereas myocyte diameter was approximately 50% larger (16.2 ± 4.0 µm vs 11.7 ± 2.4 µm [mean, SD]; P < .001). The interstitial fibrous area did not differ between the 2 groups (803 ± 422 µm2 vs 789 ± 480 µm2; P = .92). CONCLUSIONS: The study investigators observed significant cardiomyocyte hypertrophy but lower capillary density in patients with ccTGA with IVS or DTGA with IVS after PAB for retraining compared with normal control subjects. This finding suggests that inadequate capillary growth is a potential pathologic basis for mLV dysfunction occurring after retraining or anatomic repair.

The fetal lamb model of congenital diaphragmatic hernia shows altered cerebral perfusion using contrast enhanced ultrasound.

BACKGROUND: Neurodevelopmental impairment is common in survivors of congenital diaphragmatic hernia (CDH). Altered cerebral perfusion in utero may contribute to abnormal brain development in CDH patients. METHODS: 5 fetal lambs with surgical left-CDH and 5 controls underwent transuterine cranial Doppler and contrast enhanced ultrasound (CEUS). Global and regional perfusion metrics were obtained. Biometric and perfusion data were compared between groups via nonparametric Mann Whitney U test and Spearman's rank order correlation. RESULTS: No significant differences in cerebral Doppler measurements were identified between groups. By CEUS, CDH animals demonstrated significantly decreased global brain perfusion and increased transit time. With focal regions-of-interest (ROIs), there was a tendency towards decreased perfusion in the central/thalamic region in CDH but not in the peripheral brain parenchyma. Transit time was significantly increased in both ROIs in CDH, whereas flux rate was decreased in the central/thalamic region but not the peripheral brain parenchyma. Biometric CDH severity was correlated to perfusion deficit. There was no difference in cardiomyocyte histology. CONCLUSION: The fetal lamb model of CDH shows altered cerebral perfusion as measured by CEUS, correlating to disease severity. This suggests a physiological abnormality in fetal cerebrovascular perfusion that may contribute to abnormal brain development and neurodevelopmental impairment in survivors.

Correlation of Intravascular Ultrasound with Histology in Pediatric Pulmonary Vein Stenosis.

Preliminary intravascular ultrasound (IVUS) images of suspected pediatric intraluminal pulmonary vein stenosis (PVS) demonstrate wall thickening. It is unclear how the IVUS-delineated constituents of wall thickening correlate with the histology. We analyzed six postmortem formalin-fixed heart/lung specimens and four live patients with PVS as well as control pulmonary veins using IVUS and light microscopic examination. In PVS veins, IVUS demonstrated wall thickening with up to two layers of variable echogenicity, often with indistinct borders. Histologically, the veins showed fibroblastic proliferation with areas rich in myxoid matrix as well as areas with abundant collagen and elastic fibers. Discrete vein layers were obscured by scarring and elastic degeneration. A lower reflective periluminal layer by IVUS corresponded with hyperplasia of myofibroblast-like cells in abundant myxoid matrix. The hyper-reflective layer by IVUS extended to the outer edge of the vessel and corresponded to a less myxoid area with more collagen, smooth muscle and elastic fibers. The outer less reflective edge of the IVUS image correlated with a gradual transition into adventitia. Normal veins had a thin wall, correlating with histologically normal cellular and extracellular components, without intimal proliferation. IVUS may provide further understanding of the anatomy and mechanisms of pediatric pulmonary vein obstruction.

Unusual Ventriculo-Arterial Alignments and Connections.

In this issue of World Journal for Pediatric and Congenital Heart Surgery, Kari and colleagues present a case of anatomically corrected malposition {S, L, L} with ventricular septal defect and complex subaortic stenosis managed by staged biventricular repair. This rare case with interesting management strategy provides an opportunity to clarify this and related unusual ventriculo-arterial alignments.

Aortic valve replacement for infective endocarditis in an adult with uncorrected tetralogy of Fallot and pulmonary atresia.

Infective endocarditis is one of the complications encountered in patients with uncorrected tetralogy of Fallot; however, there have been only limited reports on surgical treatment of this condition. A 38-year-old man with uncorrected tetralogy of Fallot with pulmonary atresia previously palliated with modified Blalock-Taussig shunt was diagnosed with aortic valve infective endocarditis and developed severe aortic regurgitation. He underwent urgent aortic valve replacement, during which intermittent hypothermic circulatory arrest was necessary to achieve adequate myocardial protection and bloodless surgical field due to massive arterial return into the left ventricle from the collateral pulmonary circulation.

Prediction of Pulmonary to Systemic Flow Ratio in Patients With Congenital Heart Disease Using Deep Learning-Based Analysis of Chest Radiographs.

Importance: Chest radiography is a useful noninvasive modality to evaluate pulmonary blood flow status in patients with congenital heart disease. However, the predictive value of chest radiography is limited by the subjective and qualitive nature of the interpretation. Recently, deep learning has been used to analyze various images, but it has not been applied to analyzing chest radiographs in such patients. Objective: To develop and validate a quantitative method to predict the pulmonary to systemic flow ratio from chest radiographs using deep learning. Design, Setting, and Participants: This retrospective observational study included 1031 cardiac catheterizations performed for 657 patients from January 1, 2005, to April 30, 2019, at a tertiary center. Catheterizations without the Fick-derived pulmonary to systemic flow ratio or chest radiography performed within 1 month before catheterization were excluded. Seventy-eight patients (100 catheterizations) were randomly assigned for evaluation. A deep learning model that predicts the pulmonary to systemic flow ratio from chest radiographs was developed using the method of transfer learning. Main Outcomes and Measures: Whether the model can predict the pulmonary to systemic flow ratio from chest radiographs was evaluated using the intraclass correlation coefficient and Bland-Altman analysis. The diagnostic concordance rate was compared with 3 certified pediatric cardiologists. The diagnostic performance for a high pulmonary to systemic flow ratio of 2.0 or more was evaluated using cross tabulation and a receiver operating characteristic curve. Results: The study included 1031 catheterizations in 657 patients (522 males [51%]; median age, 3.4 years [interquartile range, 1.2-8.6 years]), in whom the mean (SD) Fick-derived pulmonary to systemic flow ratio was 1.43 (0.95). Diagnosis included congenital heart disease in 1008 catheterizations (98%). The intraclass correlation coefficient for the Fick-derived and deep learning-derived pulmonary to systemic flow ratio was 0.68, the log-transformed bias was 0.02, and the log-transformed precision was 0.12. The diagnostic concordance rate of the deep learning model was significantly higher than that of the experts (correctly classified 64 of 100 vs 49 of 100 chest radiographs; P = .02 [McNemar test]). For detecting a high pulmonary to systemic flow ratio, the sensitivity of the deep learning model was 0.47, the specificity was 0.95, and the area under the receiver operating curve was 0.88. Conclusions and Relevance: The present investigation demonstrated that deep learning-based analysis of chest radiographs predicted the pulmonary to systemic flow ratio in patients with congenital heart disease. These findings suggest that the deep learning-based approach may confer an objective and quantitative evaluation of chest radiographs in the congenital heart disease clinic.