Faculty Bibliography

OBJECTIVE:Several human studies have associated nitric oxide administration via the cardiopulmonary bypass circuit with decreased incidence of cardiopulmonary bypass-associated acute kidney injury, but histopathologic and serologic evidence of nitric oxide efficacy for acute kidney injury attenuation are lacking. METHODS:By using a survival ovine model (72 hours), acute kidney injury was induced by implementing low-flow cardiopulmonary bypass for 2 hours, followed by full-flow cardiopulmonary bypass for 2 hours. The nitric oxide cohort (n = 6) received exogenous nitric oxide through the cardiopulmonary bypass circuit via the oxygenator, and the control group (n = 5) received no nitric oxide. Serial serologic biomarkers and renal histopathology were obtained. RESULTS:Baseline characteristics (age, weight) and intraoperative parameters (cardiopulmonary bypass time, urine output, heart rate, arterial pH, and lactate) were equivalent (P > .10) between groups. Postoperatively, urine output, heart rate, respiratory rate, and peripheral arterial saturation were equivalent (P > .10) between groups. Post-cardiopulmonary bypass creatinine elevations from baseline were significantly greater in the control group versus the nitric oxide group at 16, 24, and 48 hours (all P < .05). Histopathologic evidence of moderate/severe acute kidney injury (epithelial necrosis, tubular slough, cast formation, glomerular edema) occurred in 60% (3/5) of the control group versus 0% (0/6) of the nitric oxide group. Cortical tubular epithelial cilia lengthening (a sensitive sign of cellular injury) was significantly greater in the control group than in the nitric oxide group (P = .012). CONCLUSIONS:In a survival ovine cardiopulmonary bypass model, nitric oxide administered with cardiopulmonary bypass demonstrated serologic and histologic evidence of renal protection from acute kidney injury. These results provide insight into 1 potential mechanism for cardiopulmonary bypass-associated acute kidney injury and supports continued study of nitric oxide via cardiopulmonary bypass circuit for prevention of acute kidney injury.

BACKGROUND:Acute cellular rejection (ACR) is common after lung transplant (LTx). We sought to determine if transplant center volume affected ACR-related outcomes in children after LTx. METHODS:The United Network for Organ Sharing (UNOS) Registry was queried for patients <18-years-of-age who underwent LTx 1987-2020. Cohorts were children who survived the first-year post transplant and were treated for ACR within that first year (ACR group) and those not treated for ACR (non-ACR). LTx center volume was defined as: high volume center (HVC) (>5LTxs/year), medium volume center (MVC) (>1≤5 LTxs/year), and low volume center (LVC) (≤1LTxs/year). RESULTS:1320 patients were enrolled into the study; 269 (20.4%) did not experience ACR. The ACR cohort was older (median 14 [11-16] vs 13 [7-16] years, p < 0.001), female (65.3% vs 57.3%, p = 0.016), had cystic fibrosis (62.3% vs 45.5%, p < 0.001), and had a higher lung allocation score (37.3 [34.6-47.8] vs 35.8 [33-42.6], p = 0.029). The ACR cohort trended (p = 0.06) towards lower survival at 5-year (37% vs 47%) and 10-year (25% vs 34%) post-LTx. Among children at HVCs, ACR occurred in 17% of recipients (n = 98/574), compared to 18.5% (n = 73/395) at MVCs and 27% (n = 100/369) at LVCs. Children treated for ACR at HVCs had higher survival than LVCs at 5-years (52% vs 29%) and 10-years (36% vs 15%) (p < 0.001) but similar survival to MVCs at 5-years (52% vs 43%) and 10-years (36% vs 24%) (p = 0.081). No survival differences were detected in MVCs vs LVCs (p = 0.14). CONCLUSIONS:ACR treated within the first post-LTx year influence survival of children. ACR incidence was lowest at higher volume centers whereas post-ACR treatment survival outcomes were also superior.

BACKGROUND:Repair of complex congenital heart disease frequently requires use of a patch as an anatomic substitute. The study's aim is to evaluate the use, effectiveness, and safety of using small intestine submucosal extracellular matrix (SIS-ECM) patches in a congenital cardiac surgery program. METHODS:This is a single-center, retrospective, cohort study of surgeries using SIS-ECM between 2012 and 2019. The SIS-ECM data were categorized by use and type (four-ply and two-ply). All reinterventions and complications were reviewed by an independent surgeon, a practicing congenital heart surgeon, and a pediatric cardiologist. RESULTS:In all, 408 SIS-ECM patches were used in 309 patients (188 male, 121 female; median age 8.5 months). Use of the patches consisted of 314 arterioplasties (77%), 22 venoplasties (5.4%), 63 intracardiac repairs (15.4%), and 9 valve repairs (2.2%). The most common use was for pulmonary artery repair (n = 181; 44.4%). Median follow-up time was 3.9 years (range, 3 days to 7.4 years). Ten patches (2.5%) required surgical reintervention (2 in the first 30 days and 5 in the first year) and 27 (6.6%) required percutaneous reinterventions (2 in the first 30 days and 22 in the first year). Between four-ply (n = 376) and two-ply (n = 32) SIS-ECM, the rate of surgical (2.1% [n = 8] vs 6.3% [n = 2], P = .18) or percutaneous reinterventions (6.4% [n = 24] vs 9.4% [n = 3], P = .46) was not different. There were no deaths related to the SIS-ECM patch or reports of calcification. CONCLUSIONS:The SIS-ECM is a viable patch option that can be used in various cardiac and vascular reconstructive surgeries with low risk of failure and calcification. Long-term, positive outcomes may be maximized by using consistent techniques and understanding the appropriate applications of the patch.