Faculty Bibliography

Connection of the right pulmonary veins to the azygous is an extremely rare variant of partial anomalous pulmonary venous connection. We describe one such case in the setting of an intact atrial septum. Surgical correction in such a situation can be challenging. We describe a successful surgical approach for this unusual variant.

OBJECTIVES:This study sought to determine the feasibility and safety of unzipping small-diameter stents (SDS) in a growing animal model. BACKGROUND:SDS implanted to relieve stenosis of blood vessels in infants may result in refractory stenosis as the child grows. If stents can be longitudinally fractured-unzipped-then the target vessel can potentially be redilated to the eventual adult vessel diameter. METHODS:Fifty stents (diameter 4 to 7 mm) were implanted in 5 neonatal piglets (mean age and weight = 1.5 weeks and 3.4 kg). Pre-mounted coronary (CS) (n = 24), biliary (BS) (n = 14), nitinol (NS) (n = 3), and renal stents (RS) (n = 9) were implanted in pulmonary arteries (n = 13), systemic arteries (n = 25), and systemic veins (n = 12). Three months later (median weight = 32 kg), unzipping was attempted by dilating the stents. RESULTS:All CS and RS unzipped at twice their nominal diameter with <20% shortening. None of the NS unzipped. The BS shortened the most (∼40%), with only 69% of the stents unzipping. Stainless steel CS and RS with an open cell design were significant predictors (p ≤ 0.01) for unzipping. On histopathology, unzipping of the BS caused the most medial dissection and vessel wall injury, while unzipping of the CS caused the least. CONCLUSIONS:Unzipping of small-diameter CS and RS implanted in systemic and pulmonary vessels is more feasible than the BS and NS. This study may encourage the implantation of small stents in infant blood vessels and aid in selection of appropriate stent type.

Common pulmonary vein atresia is a rare and usually fatal congenital anomaly, in which the pulmonary veins come together to form a confluence that does not connect to the left atrium. We report our experience with three cases of common pulmonary vein atresia and review the literature on this anomaly. The diagnosis of common pulmonary vein atresia must be entertained in any newborn that presents with cyanosis, refractory acidosis, and decreased systemic perfusion within the first 48 hours of life. Echocardiography is a useful screening tool, but cardiac catheterisation is the preferred diagnostic tool. Common pulmonary vein atresia can be fatal without surgical intervention, but survival after surgery continues to be poor.

BACKGROUND:Prolonged pleural effusion following Fontan operation is common and increases morbidity and hospital length of stay. Vasopressin (VP), a neurohypophysial hormone, has numerous effects on the cardiovascular system. The most notable is increased peripheral vascular resistance, but it may also reduce capillary leakage by tightening endothelial intercellular junctions and reducing capillary hydrostatic pressure We reviewed our experience with the perioperative administration of VP following Fontan operation. METHODS:We retrospectively reviewed the records of 62 consecutive patients who underwent Fontan operation from January 2004 to June 2014. In January 2010, VP was introduced as part of the standard perioperative management of patients undergoing Fontan operation at our center. For this retrospective observational study, patients were grouped according to the use (VP; N = 40) or nonuse (non-VP; N = 22) of VP (0.3-0.5 mU/kg/min) in the perioperative period. The primary end point analyzed was chest tube output. Secondary end points analyzed included fluid balance and length of hospital stay, with groups compared using Mann-Whitney U test. RESULTS:There was no hospital mortality. Median total chest tube output was 22 mL/kg in the VP group and 68 mL/kg in the non-VP group (P < .001). The median total duration of chest tube indwelling time was five days in the VP group and was 11 days in the non-VP group (P < .001). Median fluid balance on first postoperative day was 13 and 38 mL/kg, respectively (P < .001). Median hospital stay for VP and non-VP groups was 9 and 16 days, respectively (P = .002). CONCLUSIONS:The more recent group of patients undergoing Fontan operations, all of whom received VP perioperatively, had less chest tube output and shorter duration of chest tube drainage after the Fontan operation relative to the earlier patient group whose perioperative management did not include VP. They also experienced less positive fluid balance in the early postoperative period and shorter hospital length of stay than the patients from the earlier era.

Cancer cells tend to develop resistance to various types of anticancer agents, whether they adopt similar or distinct mechanisms to evade cell death in response to a broad spectrum of cancer therapeutics is not fully defined. Current study concludes that DNA-damaging agents (etoposide and doxorubicin), ER stressor (thapsigargin), and histone deacetylase inhibitor (apicidin) target oxidative phosphorylation (OXPHOS) for apoptosis induction, whereas other anticancer agents including staurosporine, taxol, and sorafenib induce apoptosis in an OXPHOS-independent manner. DNA-damaging agents promoted mitochondrial biogenesis accompanied by increased accumulation of cellular and mitochondrial ROS, mitochondrial protein-folding machinery, and mitochondrial unfolded protein response. Induction of mitochondrial biogenesis occurred in a caspase activation-independent mechanism but was reduced by autophagy inhibition and p53-deficiency. Abrogation of complex-I blocked DNA-damage-induced caspase activation and apoptosis, whereas inhibition of complex-II or a combined deficiency of OXPHOS complexes I, III, IV, and V due to impaired mitochondrial protein synthesis did not modulate caspase activity. Mechanistic analysis revealed that inhibition of caspase activation in response to anticancer agents associates with decreased release of mitochondrial cytochrome c in complex-I-deficient cells compared with wild type (WT) cells. Gross OXPHOS deficiencies promoted increased release of apoptosis-inducing factor from mitochondria compared with WT or complex-I-deficient cells, suggesting that cells harboring defective OXPHOS trigger caspase-dependent as well as caspase-independent apoptosis in response to anticancer agents. Interestingly, DNA-damaging agent doxorubicin showed strong binding to mitochondria, which was disrupted by complex-I-deficiency but not by complex-II-deficiency. Thapsigargin-induced caspase activation was reduced upon abrogation of complex-I or gross OXPHOS deficiency whereas a reverse trend was observed with apicidin. Together, these finding provide a new strategy for differential mitochondrial targeting in cancer therapy.

BACKGROUND:Thrombosis and occlusion of the superior vena cava (SVC) can cause massive chylothorax resulting in significant morbidity and mortality among young infants. Medical therapy is often unsuccessful. We report a new surgical technique that entails open thrombectomy and reconstruction of the SVC and innominate vein to treat this condition. METHODS:The charts of 4 consecutive infants with chylothoraces refractory to conservative management were reviewed. The operations were performed on cardiopulmonary bypass without myocardial arrest. The SVC and innominate veins were incised open, and thrombectomy was performed. This was followed by homograft patch reconstruction of both the veins. RESULTS:The infants were aged between 5 weeks to 4 months and had an average weight of 4 kg. All of them had hypoalbuminemia and evidence of hypercoagulable state. After surgical intervention, 3 had complete relief of SVC obstruction. Two of the 3 patients had complete resolution of chylous effusion, and the third patient had a significant decrease in chest tube drainage (70%) by the end of 1 week. The fourth patient had recurrence of high drainage after an initial improvement, and a subsequent angiogram demonstrated stenosis of the SVC without thrombosis. The chest tube drainage finally resolved after balloon angioplasty. CONCLUSIONS:Thrombotic occlusion of the SVC can result in chylothorax that is often not amenable to medical therapy. This is associated with significant loss of proteins and hypercoagulable state. A complete surgical relief of SVC obstruction by open thrombectomy and venoplasty can result in dramatic decrease in chylous output.

OBJECTIVE:Symptomatic neonates with Ebstein's anomaly pose significant challenge. Within this cohort, neonates with associated anatomical pulmonary atresia have higher mortality. We review our experience with this difficult subset. METHODS:A total of 32 consecutive symptomatic neonates with Ebstein's anomaly underwent surgical intervention between 1994 and 2013. Of them, 20 neonates (62%, 20/32) had associated pulmonary atresia. Patients' weights ranged from 1.9 to 3.4 kg. All patients without pulmonary atresia had two-ventricle repair. Of the 20 neonates, 16 (80%, 16/20) with Ebstein's anomaly and pulmonary atresia had two-ventricle repair and 4 had single-ventricle palliation, of which 2 underwent Starnes' palliation and 2 Blalock-Taussig shunts. Six recent patients with Ebstein's anomaly and pulmonary atresia had right ventricle to pulmonary artery valved conduit as part of their two-ventricle repair. RESULTS:Overall early mortality was 28% (9/32). For those without pulmonary atresia, mortality was 8.3% (1/12). For the entire cohort of neonates with Ebstein's anomaly and pulmonary atresia, mortality was 40% (8/20; p=0.05). Mortality for neonates with Ebstein's anomaly and pulmonary atresia having two-ventricle repair was 44% (7/16). Mortality for neonates with Ebstein's anomaly and pulmonary atresia having two-ventricle repair utilising right ventricle to pulmonary artery conduit was 16% (1/6). For those having one-ventricle repair, the mortality was 25% (1/4). CONCLUSIONS:Surgical management of neonates with Ebstein's anomaly remains challenging. For neonates with Ebstein's anomaly and anatomical pulmonary atresia, single-ventricle palliation is associated with lower early mortality compared with two-ventricle repair. This outcome advantage is negated by inclusion of right ventricle to pulmonary artery conduit as part of the two-ventricle repair.

The CentriMag ventricular assist device is an extracorporeal, third-generation, continuous flow device. The rapidity and simplicity of operation along with low priming volume make it attractive for use in children with refractory heart failure. We report the successful use of CentriMag as a bridge to recovery in a child and discuss issues that are unique to its use in children.