Host non-inflammatory neutrophils mediate the engraftment of bioengineered vascular networks

Notwithstanding remarkable progress in vascular network engineering, implanted bioengineered microvessels largely fail to form anastomoses with the host vasculature. Here, we demonstrate that implants containing assembled human vascular networks (A-Grafts) fail to engraft due to their inability to engage non-inflammatory host neutrophils upon implantation into mice. In contrast, unassembled vascular cells (U-Grafts) readily engage alternatively polarized neutrophils, which in turn serve as indispensable mediators of vascular assembly and anastomosis. The depletion of host neutrophils abrogated vascularization in U-Grafts, whereas an adoptive transfer of neutrophils fully restored vascularization in myeloid-depleted mice. Neutrophil engagement was regulated by secreted factors and was progressively silenced as the vasculature matured. Exogenous addition of factors from U-Grafts reengaged neutrophils and enhanced revascularization in A-Grafts, a process that was recapitulated by blocking Notch signaling. Our data suggest that the pro-vascularization potential of neutrophils can be harnessed to improve the engraftment of bioengineered tissues

Surgical Atrioventricular Valve Replacement With Melody Valve in Infants and Children

Background Pediatric patients with atrioventricular valve disease have limited options for prosthetic valve replacement in sizes <15 mm. Based on successful experience with the stented bovine jugular vein graft (Melody valve) in the right ventricular outflow tract, the prosthesis has been modified for surgical valve replacement in pediatric patients with atrioventricular dysfunction with the intention of subsequent valve expansion in the catheterization laboratory as the child grows. Methods and Results A multicenter, retrospective cohort study was performed among patients who underwent atrioventricular valve replacement with Melody valve at 17 participating sites from North America and Europe, including 68 patients with either mitral (n=59) or tricuspid (n=9) replacement at a median age of 8 months (range, 3 days to 13 years). The median size at implantation was 14 mm (range, 9-24 mm). Immediately postoperatively, the valve was competent with low gradients in all patients. Fifteen patients died; 3 patients underwent transplantation. Nineteen patients required reoperation for adverse outcomes, including valve explantation (n=16), left ventricular outflow tract obstruction (n=1), permanent pacemaker implantation (n=1), and paravalvular leak repair (n=1). Twenty-five patients underwent 41 episodes of catheter-based balloon expansion, exhibiting a significant decrease in median gradient ( P<0.001) with no significant increase in grade of regurgitation. Twelve months after implantation, cumulative incidence analysis indicated that 55% of the patients would be expected to be free from death, heart transplantation, structural valve deterioration, or valve replacement. Conclusions The Melody valve is a feasible option for surgical atrioventricular valve replacement in patients with hypoplastic annuli. The prosthesis shows acceptable short-term function and is amenable to catheter-based enlargement as the child grows. However, patients remain at risk for mortality and structural valve deterioration, despite adequate early valvular function. Device design and implantation techniques must be refined to reduce complications and extend durability. Clinical Trial Registration URL: https://www.clinicaltrials.gov. Unique identifier: NCT02505074

Repair of double outlet right ventricle: Midterm outcomes

Objective: Double outlet right ventricle (DORV) is a complex cardiac malformation with many anatomic variations and various approaches for surgical repair. This study aimed to describe the clinical outcomes of biventricular (BiV) repair for DORV. Methods: Patients with DORV, who underwent BiV repair between January 2000 and December 2017 were retrospectively reviewed. Group 1 underwent primary BiV repair, whereas group 2 underwent staged BiV repair over a series of operations. The decision to pursue staged approach included complexity of intracardiac anatomy, age of the patient, and the size and function of the ventricles and the atrioventricular valves. Time-dependent surgical reintervention for LVOTO and mortality were evaluated using Kaplan-Meier survival analysis. Results: A total of 238 patients with DORV underwent BiV repair at a median age of 6.2 months (range, 1.1 month-27.5 years) (158 in group 1, 80 in group 2). Twenty-two patients (7.8%) required surgical reintervention within 30 days of BiV repair. Overall survival at 5 years was 89.0%. Freedom from LVOTO reoperation at 5 years was 84%. Primary outcomes were not significantly different between groups. CAVC repair and right ventricle to pulmonary artery conduit at BiV repair were associated with higher surgical reintervention (hazard ratio, 2.9 and 1.75, respectively). Conclusions: Patients with DORV and complex anatomy may undergo staged BiV repair with acceptable outcomes. Although LVOTO is a potential complication in these patients, the rate of surgical reintervention for LVOTO does not differ significantly from patients undergoing primary BiV repair

High-dose heparin is associated with higher bleeding and thrombosis rates in pediatric patients following cardiac surgery

Objective: To determine the association between unfractionated heparin (UFH) dose and the rate of postoperative bleeding and thrombosis events in pediatric cardiac patients. We tested the hypothesis that high-dose UFH is associated with higher rates of bleeding and thrombosis. Methods: This is a retrospective review of pediatric patients admitted to the cardiac intensive care unit following cardiac surgery between November 2016 and December 2017. Peripheral venous thrombosis was excluded from analysis. Bleeding was defined as spontaneous bleeding remote from procedural manipulation. Postoperative UFH dosing strategy was categorized into 3 groups: no UFH, low-dose UFH (\u3c15 U/kg/h) and high-dose UFH (≥15 U/kg/h). Statistical analysis was performed using multivariable logistic regression. Results: We observed 966 consecutive patients (median age, 1.37 years; interquartile range, 0.27-5.50 years) during their stay in the cardiac intensive care unit. There were 94 patients (10%) with bleeding and 52 patients (5%) with thrombosis during follow-up. Patients receiving high-dose UFH experienced significantly more bleeding (odds ratio, 2.35; 95% confidence interval, 1.45-3.95) and thrombosis events (odds ratio, 3.65; 95% confidence interval, 1.81-7.38) compared with patients receiving low-dose UFH. The odds of bleeding (odds ratio, 0.81; 95% confidence interval, 0.45-1.47) and thrombosis (odds ratio, 0.59; 95% confidence interval, 0.26-1.35) were similar in the low-dose UFH and no-UFH groups. Conclusions: Bleeding remote from immediate postsurgical bleeding occurs uncommonly in pediatric patients following cardiac surgery. Anticoagulation with high-dose UFH is associated with higher bleeding rates as well as higher thrombosis rates. Indications for high-dose UFH should be carefully considered to reduce the rate of bleeding in this population

Do patients with anomalous origin of the left coronary artery benefit from an early repair of the mitral valve?

OBJECTIVES: The aim of this study was to determine mid-term outcomes of patients with anomalous origin of the left coronary artery from the pulmonary artery undergoing coronary repair only (group A) or simultaneous mitral valve repair (group B).METHODS: Patients with anomalous origin of the left coronary artery from the pulmonary artery who underwent surgery from 2000 to 2017 were reviewed. Mitral regurgitation (MR) grade (none, mild, moderate, severe), left ventricular (LV) function [ejection fraction (EF): 50%] and LV Z-scores (long axis) were assessed preoperatively and at last visit. Outcomes were compared within/between the groups using the Wilcoxon signed-rank test.RESULTS: Of 58 patients (67% women; median age 4.4months), 39 patients were in group A (67%) and 19 patients in group B (33%). The median hospital stay (11 days, interquartile range 5-18) and average follow-up time (2.60.5 years) did not differ significantly between the groups (P>0.05). Four patients in group A (10.3%) underwent mitral valve reintervention. The median MR grade differed significantly between the groups preoperatively (2 vs 3, P50%) did not differ significantly between the groups at baseline (group A: 38%/23%/38% vs group B: 58%/10%/32%, P = 0.32) or at last visit (group A: 18%/15%/67% vs group B: 26%/16%/58%, P = 0.75); both groups improved significantly (P = 0.004, P = 0.014). The mean LV Z-scores for groups A and B were 3.1 +/- 0.5 and 4.5 +/- 0.6 before surgery (P= moderate MR, the risk of mitral valve reintervention may be higher in patients undergoing coronary transfer only

Staged ventricular recruitment in patients with borderline ventricles and large ventricular septal defects

Objectives: Patients with borderline ventricles and ventricular septal defects (VSDs) who have previously undergone single ventricle palliation might be candidates for staged ventricular recruitment with the ultimate goal of biventricular conversion. This study aimed to determine the effect of atrial septal defect (ASD) restriction without VSD closure on ventricular growth in patients with borderline right or left ventricles and VSDs. Methods: Patients with borderline ventricles and VSD who underwent a staged ventricular recruitment procedure with strategies to increase blood flow through hypoplastic ventricle via ASD restriction without VSD closure after single ventricle palliation were retrospectively reviewed. Pre- and postrecruitment ventricular volumes were compared using Wilcoxon signed rank test. Results: A total of 21 patients underwent staged ventricular recruitment via ASD restriction without VSD closure at median age of 20.0 months (interquartile range [IQR], 8.0-52.5 months). At a median of 9.0 months (IQR, 8.0-11.8 months) after the recruitment procedure, there were increases in the median indexed ventricular diastolic volume (31.7 mL/m [IQR, 24.5-37.1] to 48.5 mL/m [IQR, 38.4-58.0; P \u3c.01]), median indexed systolic volume (13.3 mL/m [IQR, 9.7-18.7] to 19.5 mL/m [IQR, 16.8-29.7]; P \u3c.01), and the median indexed stroke volume (18.4 mL/m [IQR, 14.8-21.1] to 28.1 mL/m [IQR, 21.3-31.8]; P \u3c.01). Biventricular conversion was ultimately performed in 14 (67%). Two patients died after biventricular conversion. Conclusions: Staged ventricular recruitment via ASD restriction without VSD closure is associated with growth of the hypoplastic ventricle. In patients who are deemed high-risk for single ventricle, this approach might facilitate eventual biventricular conversion. Further studies are needed to identify optimal candidates for this approach. 2 2 2 2 2

Staged ventricular recruitment and biventricular conversion following single-ventricle palliation in unbalanced atrioventricular canal defects

Objective Restoration of biventricular circulation is an alternative management strategy in unbalanced atrioventricular canal defects (uAVCDs), especially in patients with risk factors for single-ventricle palliation (SVP) failure. When ventricular volume is inadequate for biventricular circulation, recruitment procedures may accommodate its growth. In this study, we review our uAVCD experience with biventricular conversion (BIVC) after prior SVP. Methods This is a single-institution, retrospective cohort study of uAVCD patients who underwent BIVC after SVP, with staged recruitment (staged) or primary BIVC (direct) between 2003 to 2018. Mortality, unplanned reinterventions, imaging, and catheterization data were analyzed. Results Sixty-five patients underwent BIVC from SVP (17 stage 1, 42 bidirectional Glenn, and 6 Fontan). Decision for conversion was based on poor SVP candidacy (n = 43) or 2 adequately sized ventricles (n = 22). Of the 65 patients, 20 patients underwent recruitment before conversion. The staged group had more severe ventricular hypoplasia than the direct group, reflected in prestaging end-diastolic volume z scores (–4.0 vs –2.6; P < .01), which significantly improved after recruitment (–4.0 to –1.8; P < .01). Median follow-up time was 1.0 years. Survival and recatheterizations were similar between both groups (hazard ratio, 0.9; 95% CI, 0.2-3.7; P = .95 and hazard ratio, 1.9; 95% CI, 0.9-4.1; P = .09), but more reoperations occurred with staged approach (hazard ratio, 3.1; 95% CI, 1.3-7.1; P = .01). Conclusions Biventricular conversion from SVP is an alternative strategy to manage uAVCD, particularly when risk factors for SVP failure are present. Severe forms of uAVCDs can be converted with staged BIVC with acceptable mortality, albeit increased reinterventions, when primary BIVC is not possible

Photo-oxidized bovine pericardium in congenital cardiac surgery: single-centre experience

Dye-mediated photo-oxidation of pericardium is an alternative method to chemical treatment with glutaraldehyde for cross-linking collagen, providing biostability of the patch material while avoiding late calcification and cytotoxicity. There are few data available, on using photo-oxidation-treated pericardium, in congenital cardiac surgery. This study reports the outcomes using Photofix™ bovine pericardium in neonates, infants, children and young adults undergoing paediatric cardiac surgery