Normoxic Management during Cardiopulmonary Bypass Does Not Reduce Cerebral Mitochondrial Dysfunction in Neonatal Swine.

Optimal oxygen management during pediatric cardiopulmonary bypass (CPB) is unknown. We previously demonstrated an increase in cortical mitochondrial reactive oxygen species and decreased mitochondrial function after CPB using hyperoxic oxygen management. This study investigates whether controlled oxygenation (normoxia) during CPB reduces cortical mitochondrial dysfunction and oxidative injury. Ten neonatal swine underwent three hours of continuous CPB at 34 °C (flow > 100 mL/kg/min) via cervical cannulation targeting a partial pressure of arterial oxygen (PaO2) goal < 150 mmHg (normoxia, n = 5) or >300 mmHg (hyperoxia, n = 5). The animals underwent continuous hemodynamic monitoring and serial arterial blood sampling. Cortical microdialysate was serially sampled to quantify the glycerol concentration (represents neuronal injury) and lactate-to-pyruvate ratio (represents bioenergetic dysfunction). The cortical tissue was analyzed via high-resolution respirometry to quantify mitochondrial oxygen consumption and reactive oxygen species generation, and cortical oxidized protein carbonyl concentrations were quantified to assess for oxidative damage. Serum PaO2 was higher in hyperoxia animals throughout CPB (p < 0.001). There were no differences in cortical glycerol concentration between groups (p > 0.2). The cortical lactate-to-pyruvate ratio was modestly elevated in hyperoxia animals (p < 0.03) but the values were not clinically significant (<30). There were no differences in cortical mitochondrial respiration (p = 0.48), protein carbonyls (p = 0.74), or reactive oxygen species generation (p = 0.93) between groups. Controlled oxygenation during CPB does not significantly affect cortical mitochondrial function or oxidative injury in the acute setting. Further evaluation of the short and long-term effects of oxygen level titration during pediatric CPB on cortical tissue and other at-risk brain regions are needed, especially in the presence of cyanosis.

Early Impairment of Cerebral Bioenergetics After Cardiopulmonary Bypass in Neonatal Swine.

Objectives: We previously demonstrated cerebral mitochondrial dysfunction in neonatal swine immediately following a period of full-flow cardiopulmonary bypass (CPB). The extent to which this dysfunction persists in the postoperative period and its correlation with other markers of cerebral bioenergetic failure and injury is unknown. We utilized a neonatal swine model to investigate the early evolution of mitochondrial function and cerebral bioenergetic failure after CPB. Methods: Twenty piglets (mean weight 4.4 ± 0.5 kg) underwent 3 h of CPB at 34 °C via cervical cannulation and were followed for 8, 12, 18, or 24 h (n = 5 per group). Markers of brain tissue damage (glycerol) and bioenergetic dysfunction (lactate to pyruvate ratio) were continuously measured in cerebral microdialysate samples. Control animals (n = 3, mean weight 4.1 ± 1.2 kg) did not undergo cannulation or CPB. Brain tissue was extracted immediately after euthanasia to obtain ex-vivo cortical mitochondrial respiration and frequency of cortical microglial nodules (indicative of cerebral microinfarctions) via neuropathology. Results: Both the lactate to pyruvate ratio (P < .0001) and glycerol levels (P = .01) increased in cerebral microdialysate within 8 h after CPB. At 24 h post-CPB, cortical mitochondrial respiration was significantly decreased compared with controls (P = .046). The presence of microglial nodules increased throughout the study period (24 h) (P = .01, R2 = 0.9). Conclusion: CPB results in impaired cerebral bioenergetics that persist for at least 24 h. During this period of bioenergetic impairment, there may be increased susceptibility to secondary injury related to alterations in metabolic delivery or demand, such as hypoglycemia, seizures, and decreased cerebral blood flow.

Late Pulmonary Autograft Dilation: Can We Make a Good Operation Great? The Supported Ross.

The Ross procedure is an excellent option for aortic valve replacement resulting in outstanding hemodynamic performance and the ability to avoid systemic anticoagulation. The long-term durability of the autograft is generally good but concerns for later aortic root dilation with ensuing neoaortic insufficiency have prompted efforts to stabilize the autograft, root, sinuses and Sino-tubular junction in order to delay or entirely avoid late reinterventions on the neoaortic root. We have employed an inclusion technique, supporting the Auto-graft in a Terumo Gelweave™ Valsalva graft. We performed a retrospective study of all 129 patients undergoing the Ross procedure from 1992 to 2019 at Children's Wisconsin. Fifty-one underwent the supported Ross (SR) and 78 underwent unsupported Ross (UR). Structured clinical data was collected and echocardiograms were reviewed. Median follow-up was 4.9 years (up to 22.6 years) for UR patients and 3.6 years (up to 11.4 years) for SR patients. In order to provide a fair comparison, we sub -analyzed patients aged 10 to 18 years who underwent the Ross procedure, 16 who underwent the UR and 18 patients who underwent the SR. Change in aortic annulus diameter (P = 0.002), aortic sinus diameter (P = 0.001) change in left ventricular function (P = 0.039) and change in aortic insufficiency (P = 0.008) were all worse in UR. The SR is simple, reproducible, and predictable. It seems to prevent change in annulus diameter, sinus diameter and to reduce late neoaortic insufficiency. Longer follow-up with a larger group of patients is required to draw definitive conclusions.

A case-control study of bleeding risk in children with 22q11.2 deletion syndrome undergoing cardiac surgery.

Previous research suggests that individuals with 22q11.2 deletion syndrome (DS) have an increased risk of bleeding following cardiac surgery. However, current guidelines for management of patients with 22q11.2DS do not provide specific recommendations for perioperative management. This study sought to identify specific risk factors for bleeding in this patient population. Examine the factors determining bleeding and transfusion requirements in patients with 22q11.2DS undergoing cardiac surgery. This was a single center review of patients who underwent cardiac surgery at the Children's Hospital of Philadelphia from 2000 to 2016. Data was extracted from the medical record. Frequency of bleeding events, laboratory values, and transfusion requirements were compared. We included 226 patients with 22q11.2DS and 506 controls. Bleeding events were identified in 13 patients with 22q11.2DS (5.8%) and 27 controls (5.3%). Platelet counts were lower among patients with 22q11.2DS than in control patients, but not statistically different comparing bleeding to not bleeding. Patients with 22q11.2DS received more transfusions (regardless of bleeding status). However, multivariate analysis showed only procedure type was associated with increased risk of bleeding (p = .012). The overall risk of bleeding when undergoing cardiac surgery is not different in patients with 22q11.2DS compared to non-deleted patients. Though platelet counts were lower in patients with 22q11.2DS, only procedure type was significantly associated with an increased risk of bleeding.

Contemporary outcomes for functional single ventricle with total anomalous pulmonary venous connection.

OBJECTIVE: In 2004, we reported improved early survival for patients with functional single ventricle anatomy and total anomalous pulmonary venous connection. This study sought to discover if outcomes have been ameliorated in the contemporary era. METHODS: This was a single-center review of patients with single ventricle anatomy and total anomalous pulmonary venous connection who were admitted from 1984 to 2021. The cohort was divided into similarly sized groups by date of admission: Era 1: 1984 to 1992, Era 2: 1993 to 2007, and Era 3: 2008 to 2021. Survival was compared, and Cox proportional hazards models were used to evaluate the likelihood of mortality. RESULTS: We included 190 patients with single ventricle anatomy and total anomalous pulmonary venous connection. Unbalanced atrioventricular canal defect (70%) was the most common primary diagnosis. The most common type of total anomalous pulmonary venous connection was supracardiac (49%). Approximately one-third (32%) of patients had pulmonary venous obstruction. There were no significant differences in patient characteristics across eras. Early survival after initial palliative operation improved between Eras 1 and 2, and then remained stable in Era 3. Overall survival improved from Era 1 to Eras 2 and 3 (P < .001), but not between Era 2 and 3. Survival to 10 years by Eras 1 to 3 was 15%, 51%, and 54%, respectively. The anatomic features associated with worse survival were hypoplastic left heart syndrome diagnosis (hazard ratio, 1.60; 1.04-2.57) and pulmonary venous obstruction (hazard ratio, 1.80; 1.24-2.69). CONCLUSIONS: Overall survival for patients with single ventricle anatomy and total anomalous pulmonary venous connection has plateaued since the early 2000s. Even in the most recent era, survival to age 10 years remains less than 60%. Risk factors for mortality include the diagnosis of hypoplastic left heart syndrome and pulmonary venous obstruction. Further studies should focus on identification of the pathophysiological factors underlying the increased mortality.

High-Risk Anatomic Subsets in Hypoplastic Left Heart Syndrome.

Despite overall improvements in outcomes for patients with hypoplastic left heart syndrome, there remain anatomic features that can place these patients at higher risk throughout their treatment course. These include severe preoperative obstruction to pulmonary venous return, restrictive atrial septum, coronary fistulae, severe tricuspid regurgitation, smaller ascending aorta diameter (especially if <2 mm), and poor ventricular function. The risk of traditional staged palliation has led to the development of alternative strategies for such patients. To further improve the outcomes, we must continue to diligently examine and study anatomic details in HLHS patients.

Reintervention for Superior Vena Cava Obstruction After Heart Transplant.

BACKGROUND: Children undergoing orthotopic heart transplant (OHT) may require complex reconstruction of superior vena cava (SVC) anomalies. SVC anatomy and mode of reconstruction are potential risk factors for SVC obstruction. METHODS: A retrospective single-center review was conducted of patients undergoing initial OHT between January 1, 1990, and July 1, 2021. Simple SVC anatomy included a single right SVC to the right atrium or bilateral SVCs with a left SVC to an intact coronary sinus, without prior superior cavopulmonary connection. Presence of anomalous SVC anatomy, superior cavopulmonary connection, or previous atrial switch operation defined complex anatomy. Reconstructive strategies included atrial anastomosis; direct SVC-to-SVC anastomosis; and augmented SVC anastomosis using innominate vein, patch, cavopulmonary connection, or interposition graft. The primary outcome was reintervention for SVC obstruction. RESULTS: Of 288 patients, pretransplant diagnoses included congenital heart disease (n = 155 [54%]), cardiomyopathy (n = 125 [43%]), and other (n = 8 [3%]). Most (n = 208 [72%]) had simple SVC anatomy compared with complex SVC anatomy (80 [28%]). Reintervention for SVC obstruction occurred in 15 of 80 (19%) with complex anatomy and 1 of 208 (0.5%) with simple anatomy (P = .0001). Reintervention was more common when innominate vein or a patch was used (9/25 [36%]) compared with an interposition graft (1/7 [14%]) or direct anastomosis (6/82 [7%]; χ2 = 13.1; P = .001). Most reinterventions occurred within 30 days of OHT (14/16 [88%]). CONCLUSIONS: Patients with complex SVC anatomy have a higher rate of reintervention for SVC obstruction after OHT compared with those with simple SVC anatomy. In cases of complex SVC anatomy, interposition grafts may be associated with less reintervention compared with complex reconstructions using donor tissue.

Chromosome 22q11 copy number variants and single ventricle CHD.

OBJECTIVES: CHD is an important phenotypic feature of chromosome 22q11.2 copy number variants. Biventricular repair is usually possible, however there are rare reports of patients with chromosome 22q copy number variants and functional single ventricle cardiac disease. METHODS: This is a single centre retrospective review of patients with chromosome 22q copy number variants who underwent staged single ventricle reconstructive surgery between 1 July, 1984 and 31 December, 2020. RESULTS: Seventeen patients met inclusion criteria. The most common diagnosis was hypoplastic left heart syndrome (n = 8) and vascular anomalies were present in 13 patients. A microdeletion of the chromosome 22 A-D low-copy repeat was present in 13 patients, and the remaining had a duplication. About half of the patients had documented craniofacial abnormalities and/or hypocalcaemia, and developmental delay was very common. Fifteen patients had a Norwood operation, 10 patients had a superior cavopulmonary anastomosis, and 7 patients had a Fontan. Two patients had cardiac transplantation after Fontan. Overall survival is 64% at 1 year, and 58% at 5 and 10 years. Most deaths occurred following Norwood operation (n = 5). CONCLUSIONS: CHD necessitating single ventricle reconstruction associated with chromosome 22q copy number variants is not common, but typically occurs as a variant of hypoplastic left heart syndrome with the usual cytogenetic microdeletion. The most common neonatal surgical intervention performed is the Norwood, where most of the mortality burden occurs. Associated anomalies and medical issues may cause additional morbidity after cardiac surgery, but survival is similar to infants with other types of single ventricle disease.

Off-Pump Explant of a Left Ventricular Assist Device Using a Recovery Plug in a Pediatric Patient.

Though the numbers remain small, the use of continuous-flow left ventricular assist devices as a bridge to recovery in pediatric patients has been increasing. Select patients may have sufficient myocardial recovery to allow for device removal. Here, we describe a 13-year old requiring left ventricular assist device implantation for myocarditis who was referred for explant of the device after recovery. This was performed via thoracotomy, without cardiopulmonary bypass, using a newly developed titanium recovery plug that is custom designed to fit the HeartMate 3.

Risk Factors for Nonhome Discharge After Esophagectomy for Neoplastic Disease.

BACKGROUND: Esophagectomies are known to be technically challenging operations that create significant physiologic changes. These patients often require assisted care postoperatively that necessitates a nonhome discharge. The purpose of this study was to assess factors associated with nonhome discharge after esophagectomy for neoplastic disease. METHODS: The 2016 to 2017 American College of Surgeons National Surgical Quality Improvement Program Esophagectomy database was queried to identify patients who underwent esophagectomy for a neoplasm. Patients were excluded if they died within 30 days of their operation, the index operation was considered emergent, or had missing data for the variables of interest. Multivariable analysis was performed to identify which factors were predictive of nonhome discharge. RESULTS: One thousand seven patients were included. Of those, 121 (12.0%) had a nonhome discharge. Multivariable analysis showed that the following factors were associated with nonhome discharge: Modified Charlson comorbidity index (adjusted odds ratio [aOR], 2.04; 95% confidence interval [CI], 1.49-2.86), partially dependent preoperative functional status (aOR, 13.18; 95% CI, 1.07-315.67), urinary tract infection (aOR, 5.25; 95% CI, 1.32-20.41), and length of stay (aOR, 1.12; 95% CI, 1.08-1.16). CONCLUSIONS: We identified various factors associated with nonhome discharge. Early identification of patients who are at risk for nonhome discharge is important for early discharge planning, which may decrease nonmedical delays and healthcare costs.