Pre-Glenn aorto-pulmonary collaterals in single-ventricle patients.

BACKGROUND: In single-ventricle patients undergoing staged-bidirectional Glenn, 36-59% have aorto-pulmonary collateral flow, but risk factors and clinical outcomes are unknown. We hypothesise that shunt type and catheter haemodynamics may predict pre-bidirectional Glenn aorto-pulmonary collateral burden, which may predict death/transplantation, pulmonary artery or aorto-pulmonary collateral intervention. METHODS: Retrospective cohort study of patients undergoing a Norwood procedure for single-ventricle anatomy. Covariates included clinical and haemodynamic characteristics up to/including pre-bidirectional Glenn catheterisation and aorto-pulmonary collateral burden at pre-bidirectional Glenn catheterisation. Multivariable models used to evaluate relationships between risk factors and outcomes. RESULTS: From January 2011 to March 2016, 104 patients underwent Norwood intervention. Male sex (odds ratio 3.36, 95% confidence interval 1.17-11.4), age at pre-bidirectional Glenn assessment (2.12, 1.33-3.39 per month), and pulmonary to systemic flow ratio (1.23, 1.08-1.41 per 0.1 unit) were associated with aorto-pulmonary collateral burden. Aorto-pulmonary collateral burden was not associated with death/transplantation (hazard ratio 1.19, 95% confidence interval 0.37-3.85), pulmonary artery (sub-hazard ratio 1.38, 0.32-2.61), or aorto-pulmonary collateral interventions (sub-hazard ratio 1.11, 0.21-5.76). Longer post-Norwood length of stay was associated with greater risk of death/transplantation (hazard ratio 1.22 per week, 95% confidence interval 1.08-1.38), but lower risk of aorto-pulmonary collateral intervention (sub-hazard ratio 0.86 per week, 95% confidence interval 0.75-0.98). Time to pre-bidirectional Glenn catheterisation was associated with lower risk of pulmonary artery (sub-hazard ratio 0.80 per month, 95% confidence interval 0.65-0.98) and aorto-pulmonary collateral intervention (sub-hazard ratio 0.79, 0.63-0.99). Probability of moderate/severe aorto-pulmonary collateral burden increased with left-to-right shunt (22.5% at <1.0, 57.6% at >1.4) and the age at pre-bidirectional Glenn catheterisation (10.6% at <2 months, 56.9% at >5 months). CONCLUSIONS: Aorto-pulmonary collateral burden is common after Norwood procedure and increases as age at bidirectional Glenn increases. As expected, higher pulmonary to systemic flow ratio is a marker for greater aorto-pulmonary collateral burden pre-bi-directional Glenn; aorto-pulmonary collateral burden does not confer risk of death/transplantation or pulmonary artery intervention.

Major Aortopulmonary Collateral Arteries Requiring Percutaneous Intervention Following the Arterial Switch Operation: A Case Series and Systematic Review.

Background: Dextro transposition of the great arteries (d-TGA) is the most common critical congenital cardiac defect surgically treated in the neonatal period by arterial switch operation (ASO). Major aortopulmonary collaterals (MAPCAs) can be present in this population and may complicate the early postoperative period. Our aim was to review our institutional data and systematically review the available literature to provide further insight on the clinical significance of MAPCAs during the early postoperative course after ASO. Methods: This is a retrospective study of patients with simple d-TGA who underwent ASO between March 1998 and September 2020 at Boston Children's Hospital. The MEDLINE, Embase, and Cochrane databases were searched from inception to June 2020. Results: Of the 671 d-TGA patients who underwent ASO at our center, 13 (1.9%) were diagnosed with MAPCAs. Five were diagnosed before ASO, while eight were diagnosed after ASO. Of these, two patients required catheterization for MAPCAs coiling during the same hospitalization on the 2nd and 11th postoperative days. The systematic review retrieved a total of 34 articles after duplicates were removed. Finally, nine studies reporting on 23 patients were deemed eligible for our analysis. The average time to MAPCAs coiling was 12 days, while the mean hospital stay was 36 days. Conclusions: MAPCAs should be included in the differential diagnosis of ASO complicated by cardiac or respiratory failure, or pulmonary hemorrhage acutely postoperatively. Once managed, recovery of these patients is predictable, and mortality is low. Further studies investigating the diagnostic value of echocardiography and the long-term outcomes of these MAPCAs are necessary.

Better preoperative exercise function is associated with shorter hospital stay after paediatric pulmonary valve replacement or conduit revision.

Exercise capacity is a modifiable factor in patients with CHD that has been related to surgical outcomes in adults. We hypothesised that this was true for children undergoing surgical pulmonary valve replacement; therefore, the relationship of preoperative percent predicted peak oxygen consumption to surgical outcomes as measured by total hospital length of stay was explored. METHODS: Single centre retrospective cohort study of patients aged 8-18 years who underwent surgical pulmonary valve replacement. The primary predictor was preoperative percent predicted peak oxygen consumption, and primary outcome was total hospital length of stay. Clinical, imaging, and cardiopulmonary exercise test data were reviewed and compared to total hospital length of stay. Cox proportional hazards regression was used to examine the association between total hospital length of stay and percent predicted peak oxygen consumption. RESULTS: Three-hundred and seventy patients undergoing pulmonary valve replacement/conduit change between 2003 and 2017 at Boston Children's Hospital were identified. Ninety had preoperative cardiopulmonary exercise tests within 6 months of surgery. Exclusion for inadequate exercise data (n = 3) and imaging data (n = 1) left 86 patients for review. Patients with percent predicted peak oxygen consumption ≥ 70% (n = 46, 53%) had shorter total hospital length of stay (4.4 days) than the 40 with percent predicted peak oxygen consumption <70% (5.4 days, p = 0.007). Median percent predicted peak oxygen consumption increased over sequential surgical eras (p < 0.001), but total hospital length of stay did not correlate with surgical era, preoperative left ventricular function, or preoperative right ventricular dilation. CONCLUSION: Children undergoing surgical pulmonary valve replacement with better preoperative exercise capacity had shorter total hospital length of stay. Exercise capacity is a potentially modifiable factor prior to and after pulmonary valve replacement. Until more patients systematically undergo cardiopulmonary exercise tests, the full impact of optimisation of exercise capacity will not be known.

Risk Factors for Left Ventricular Dysfunction Following Surgical Management of Cardiac Fibroma.

BACKGROUND: Surgical resection of cardiac fibromas in children reduces hemodynamic and arrhythmia burden; however, little is known about postoperative left ventricular (LV) function. We aimed to evaluate factors associated with postoperative LV dysfunction. METHODS: In this retrospective observational cohort study, imaging data were reviewed from 41 patients who had undergone surgical resection of a cardiac fibroma. Tumor volume was indexed to body surface area (tumor volume index). Right ventricular tumors were excluded from analysis of postoperative ventricular function. Postoperative regional wall motion abnormality score was defined as number of wall segments with regional wall motion abnormality, and LV dysfunction was defined as LV ejection fraction <50%. Cardiovascular magnetic resonance-derived strain was low if <5%ile by previously published normative data. RESULTS: Of 41 patients who underwent resection at a median age of 2.1 years (range, 0.5-19), 37 fibromas were in the LV, (29 free wall and 8 septal), and 4 in the right ventricle. Preoperative median tumor volume index was 66 mL/m2 (range, 11-376). Of 37 patients with LV tumors, younger patients had larger tumor volume index and higher grades of preoperative mitral regurgitation (P<0.001). Larger tumor volume index correlated with higher postoperative regional wall motion abnormality score (P<0.001). By paired pre- and post-operative cardiovascular magnetic resonance (n=14), LV end-diastolic volume increased (mean 76 versus 101 mL/m2, P=0.011), with decreased LV ejection fraction (mean 60% versus 55%, P=0.014), a higher prevalence of low global circumferential strain (36% versus 64%, P=0.045), and decreased cardiac index (mean 4.8 versus 3.9 L/[min·m2], P=0.039). More than mild preoperative mitral regurgitation was the only independent predictor of predischarge LV dysfunction (odds ratio, 22 [95% CI, 2.8-179], P=0.008). CONCLUSIONS: Surgical resection of LV fibroma is associated with regional wall motion abnormality, increased LV volume, and reduced systolic function. Children with significant preoperative mitral regurgitation are at highest risk for LV dysfunction and warrant ongoing close surveillance.

Technical Performance Score's Association With Arterial Switch Operation Outcomes.

BACKGROUND: Outcomes after the arterial switch operation (ASO) for dextro-transposition of the great arteries have improved significantly since its inception in the 1980s. This study reviews contemporaneous outcomes and predictors for late reinterventions after ASO. METHODS: We retrospectively reviewed patients who underwent ASO for dextro-transposition of the great arteries from 1997 to 2017. Technical performance score (TPS) class (class 1, trivial or no residua; class 2, minor residua; class 3, major residua or reintervention) was assigned at discharge based on echocardiographic evaluation of components of the ASO. Multivariable Cox regression identified patient- and procedure-specific factors associated with postdischarge reinterventions. RESULTS: Among 598 patients, 410 (69%) underwent ASO and 188 (31%) underwent ASO with ventricular septal defect repair. Median age at surgery was 5 days (interquartile range, 3 to 7); median follow-up time was 8.2 years; 408 (68%) were male; 50 (8.3%) were premature; and 10 (1.7%) had noncardiac anomalies or syndromes. Survival to hospital discharge was 98% (n = 591). Among 349 patients with follow-up, freedom from unplanned reintervent2ion at 5 years was 99% for TPS class 1, compared with 84% for class 2 and 30% for class 3. On multivariable Cox regression, classes 2 and 3 had significantly higher hazard for reintervention (class 2 hazard ratio 10.6; 95% confidence interval, 2.5 to 44.2; P = .001; class 3 hazard ratio 58.2, 95% confidence interval, 13.1 to 259; P < .001). CONCLUSIONS: At our center, ASO was associated with relatively low mortality. Class 2 and class 3 TPS were the most important independent predictors of reinterventions after discharge. Therefore, TPS can serve as a tool for identifying high-risk patients who warrant closer follow-up.

Mechanical Mitral Valve Replacement: A Multicenter Study of Outcomes With Use of 15- to 17-mm Prostheses.

BACKGROUND: The aim of this study was to evaluate early and mid-term outcomes (mortality and prosthetic valve reintervention) after mitral valve replacement with 15- to 17-mm mechanical prostheses. METHODS: A multicenter, retrospective cohort study was performed among patients who underwent mitral valve replacement with a 15- to 17-mm mechanical prosthesis at 6 congenital cardiac centers: 5 in The Netherlands and 1 in the United States. Baseline, operative, and follow-up data were evaluated. RESULTS: Mitral valve replacement was performed in 61 infants (15 mm, n = 17 [28%]; 16 mm, n = 18 [29%]; 17 mm, n = 26 [43%]), of whom 27 (47%) were admitted to the intensive care unit before surgery and 22 (39%) required ventilator support. Median age at surgery was 5.9 months (interquartile range [IQR] 3.2-17.4), and median weight was 5.7 kg (IQR, 4.5-8.8). There were 13 in-hospital deaths (21%) and 8 late deaths (17%, among 48 hospital survivors). Major adverse events occurred in 34 (56%). Median follow-up was 4.0 years (IQR, 0.4-12.5) First prosthetic valve replacement (n = 27 [44%]) occurred at a median of 3.7 years (IQR, 1.9-6.8). Prosthetic valve endocarditis was not reported, and there was no mortality related to prosthesis replacement. Other reinterventions included permanent pacemaker implantation (n = 9 [15%]), subaortic stenosis resection (n = 4 [7%]), aortic valve repair (n = 3 [5%], and aortic valve replacement (n = 6 [10%]). CONCLUSIONS: Mitral valve replacement with 15- to 17-mm mechanical prostheses is an important alternative to save critically ill neonates and infants in whom the mitral valve cannot be repaired. Prosthesis replacement for outgrowth can be carried out with low risk.

Intestinal basolateral lipid substrate transport is linked to chylomicron secretion and is regulated by apoC-III.

Chylomicron metabolism is critical for determining plasma levels of triacylglycerols (TAGs) and cholesterol, both of which are risk factors for CVD. The rates of chylomicron secretion and remnant clearance are controlled by intracellular and extracellular factors, including apoC-III. We have previously shown that human apoC-III overexpression in mice (apoC-IIITg mice) decreases the rate of chylomicron secretion into lymph, as well as the TAG composition in chylomicrons. We now find that this decrease in chylomicron secretion is not due to the intracellular effects of apoC-III, but instead that primary murine enteroids are capable of taking up TAG from TAG-rich lipoproteins (TRLs) on their basolateral surface; and via Seahorse analyses, we find that mitochondrial respiration is induced by basolateral TRLs. Furthermore, TAG uptake into the enterocyte is inhibited when excess apoC-III is present on TRLs. In vivo, we find that dietary TAG is diverted from the cytosolic lipid droplets and driven toward mitochondrial FA oxidation when plasma apoC-III is high (or when basolateral substrates are absent). We propose that this pathway of basolateral lipid substrate transport (BLST) plays a physiologically relevant role in the maintenance of dietary lipid absorption and chylomicron secretion. Further, when apoC-III is in excess, it inhibits BLST and chylomicron secretion.