Prosthetic materials available for pediatric pulmonary valve replacement (PVR) lack growth potential, inevitably leading to a size mismatch. Small intestine submucosa–derived extracellular matrix (SIS-ECM) has been suggested to possess regenerative properties. We aimed to investigate its function and potential to increase in size as a PVR in a piglet. An SIS-ECM trileaflet valved conduit was designed. Hanford minipigs, n = 6 (10-34 kg), underwent PVR with an intended survival of six months, with monthly echocardiograms evaluating valve size and function. The conduit was excised for histologic analysis. Of the six, one was sacrificed at three months for midterm analysis, and one at month 3 due to endocarditis. The remaining four constituted the study cohort. The piglet weight increased by 186% (19.56 ± 10.22 kg to 56.00 ± 7.87 kg). Conduit size increased by 30% (1.42 ± 0.14 cm to 1.84 ± 0.14 cm; P < .01). The native right ventricular outflow tract increased by 43% and the native pulmonary artery by 84%, resulting in a peak gradient increase from 10.08 ± 2.47 mm Hg to 36.25 ± 18.80 mm Hg (P = .03). Additionally, all valves developed at least moderate regurgitation. Conduit histology showed advanced remodeling with myofibroblast infiltration, neovascularization, and endothelialization. The leaflets remodeled beginning at the base with the leaflet edge being less cellular. In addition to the known endocarditis, bacterial colonies were discovered within a leaflet in another. The SIS-ECM valved conduit implanted into a piglet demonstrated cellular infiltration with vascular remodeling and an increase in diameter. Conduit stenosis was a result of slower rates of size increase than native tissue. Suboptimal leaflet performance requires design modifications.
25 April 2018 in World Journal for Pediatric and Congenital Heart Surgery
Anomalous systemic arterial supply to the basal segments of the left lower lobe without coexisting pulmonary artery connection is a rare anomaly. Most feel treatment is necessary; however, the ideal strategy is unclear. Treatments described include embolization, pulmonary resection, or anastomosis to the native pulmonary artery. We recently encountered an infant with this anomaly and present a literature review summarizing all recent reports. Additionally, we describe a novel surgical technique to create a tension-free anastomosis utilizing segmental aortic translocation that we employed in our patient due to a large distance between the anomalous vessel and native left pulmonary artery.
Atrial fibrillation (AF) occurs in 30% of patients with mitral regurgitation referred for surgical intervention. However, the underlying mechanisms in this population are poorly understood. This study examined the effects of acute left atrial volume overload on atrial electrophysiology and the inducibility of AF. Ten canines underwent insertion of an atrioventricular shunt between the left ventricle and left atrium. Shunt and aortic flows were calculated, and the shunt was titrated to a shunt fraction to 40% to 50% of cardiac output. An epicardial plaque with 250 bipolar electrodes was used to determine activation and refractory periods. Biatrial pressures and volumes, conduction times, and atrial fibrillation inducibility were recorded. Data were collected at baseline and 20 minutes after shunt opening and closure. Mean shunt flow was 1.3 ± 0.5 L/min with a shunt fraction of 43% ± 6% simulating moderate to severe mitral regurgitation. Compared with baseline, left atrial volumes and maximum pressures increased by 27% and 29%, respectively, after shunt opening. Biatrial effective refractory periods did not change significantly after shunt opening or closure. Conduction times increased by 9% with shunt opening and returned to baseline after closure. AF duration or inducibility did not change with shunt opening. This canine model of mitral regurgitation demonstrated that acute left atrial volume overload did not increase the inducibility of atrial arrhythmias in contrast with experimental and clinical findings of chronic left atrial volume overload. This suggests that the substrates for AF in patients with mitral regurgitation are a result of chronic remodeling.
Vascular rings represent a heterogeneous set of aberrant great vessel anatomic configurations which can cause respiratory symptoms or dysphagia due to tracheal or oesophageal compression. These symptoms can be subtle and may present at varied ages. More recently, many have been identified in patients without symptoms, including fetal echocardiogram, resulting in a conundrum for practitioners when attempting to determine who will benefit from surgical correction. Here, we provide a review of vascular rings and a guide to the practitioner on when to consider additional imaging or referral. Additionally, we discuss the changing landscape regarding asymptomatic patients and fetal echocardiogram.
Though rare, rituximab has been reported to induce severe pulmonary edema. We describe the first report of ECLS utilization for this indication. A 31-year-old female with severe thrombotic thrombocytopenic purpura developed florid pulmonary edema after rituximab infusion. Despite advanced ventilatory settings, she developed severe respiratory acidosis and remained hypoxemic with a significant vasopressor requirement. Since her pulmonary insult was likely transient, ECLS was considered. Due to combined cardiorespiratory failure, she received support with peripheral venoarterial ECLS. During her ECLS course, she received daily plasmapheresis and high dose steroids. Her pulmonary function recovered and she was decannulated after 8 days. She was discharged after 23 days without residual sequelae.
Improving the Pipeline \citeGorka-poster:2017 is a capacity-building NSF funded project to increase the number of Information Assurance and Cyber Defense (IA/CD) professionals. The project developed course materials to allow instruction of college-level cybersecurity concepts to high-school students. The goal was to make the content more accessible, and in turn, to introduce the prospect of a career in security to younger students. Course materials created for this grant are freely available. This paper discusses how to access the materials.