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Hypoplastic left heart syndrome
Jean Connor, Ravi Thiagarajan
Orphanet Journal of Rare Diseases , 2007, DOI: 10.1186/1750-1172-2-23
Abstract: The congenital heart lesion more commonly known today as hypoplastic left heart syndrome (HLHS) was initially termed hypoplasia of the aortic tract complex by Lev in 1952 [1]. This initial description resulted from examination of a series of specimens found to have isolated hypoplasia of the aorta, hypoplasia of the aorta and ventricular septal defect, and hypoplasia of the aorta with aortic stenosis or atresia, with and without mitral stenosis or atresia. The series of Lev was followed by the study of Noonan and Nadas, who in 1958 first used the term hypoplastic left heart syndrome collectively to describe their series of specimens with multiple malformations involving left-sided structures of the heart [2].Hypoplastic left heart syndrome refers to the abnormal development of the left-sided cardiac structures, resulting in obstruction to blood flow from the left ventricular outflow tract. In addition, the syndrome includes underdevelopment of the left ventricle, aorta, and aortic arch, as well as mitral atresia or stenosis. The severity of outflow obstruction, the left heart structures involved, and the degree of left ventricular and aortic hypoplasia, may vary among patients, resulting in a spectrum of patients with varying levels of severity [3].The syndrome has been reported to occur in approximately 0.016 to 0.036% of all live births [4-7]. It accounts for 1 to 3.8 % of all congenital cardiac malformations [8]. Up to seven-tenths of cases are reported to occur in males [4]. The recurrence risk in siblings is 0.5%, with other forms of congenitally malformed hearts seen in 13.5% [9].Newborn infants generally are born at full term, and initially appear healthy. With closure of the arterial duct, the systemic perfusion becomes decreased, resulting in hypoxemia, acidosis, and shock. Usually, no heart murmur, or a non-specific heart murmur, may be detected. The second heart sound is loud and single because of aortic atresia. Often the liver is enlarged secondary to c
Stenosis of a Reconstructed Aorta Caused a Paradoxical Diastolic Pressure Gradient After Norwood Operation
Satoshi Masutani, Hirofumi Saiki, Hirotaka Ishido and Hideaki Senzaki
Clinical Medicine Insights: Cardiology , 2012, DOI: 10.4137/CMC.S9789
Abstract: An infant with hypoplastic left heart syndrome showed paroxysmal episodes of bradycardia, hypotension, and hypoxemia upon crying after modified Norwood operation. Echocardiography showed decreased right ventricular ejection with grade III tricuspid regurgitation, a markedly enlarged aortic arch, and accelerated blood flow distal to the enlarged aorta. Aortography demonstrated an aneurysmal neo-aorta with an apple-shaped appearance. The pressure measurements revealed intriguing aortic hemodynamics: the diastolic pressure of the ascending aorta was lower than that of the descending aorta (42 mmHg vs. 52 mmHg) despite no systolic pressure gradient. Markedly reduced compliance in the ascending aorta relative to that in the descending aorta, which was suggested by the difference in time constant of aortic pressure decay, may explain this hemodynamics. Impaired coronary circulation caused by lowered diastolic pressure in ascending aorta was indicated by reduced subendocardial viability ratio, and may account for her symptom and lowered ventricular ejection. The patient's condition was indeed significantly improved by surgical correction of the aortic shape. This case highlights the importance of aortic shape and properties after Norwood operation.
Diminutive polyps and rectal bleeding: An overview
I. Bouzakis
Annals of Gastroenterology , 2007,
Abstract: Rectal bleeding is very common in the general population. It is usually minimal, with outlet-type characteristics, but it can also be an expression of lower gastrointestinal bleeding. Colon investigation is usually indicated during rectal bleeding evaluation. Diminutive polyps cause no symptoms and they are an incidental finding in up to 50% of colonoscopies for various indications. Distal hyperplastic polyps are considered harmless. The natural history of adenomas, especially the diminutive ones, is largely unknown. Diminutive adenomas are rarely histologically advanced. Distal advanced diminutive adenomas or =3 distal diminutive tubular adenomas, can be markers of advanced proximal neoplasia. The importance of 1-2 diminutive tubular adenomas is highly controversial. Endoscopic removal of all polyps, although not specifically studied for diminutive ones, results in significant decrease of colorectal cancer incidence. Key words: rectal bleeding, minimal rectal bleeding, adenomas, hyperplastic polyps, diminutive polyps, colorectal cancer, colonoscopy
Simplified aortic cannulation (SAC) – a useful technique for neonates with small aortas
Christopher J Knott-Craig, Peter Pastuszko, Edward D Overholt
Journal of Cardiothoracic Surgery , 2006, DOI: 10.1186/1749-8090-1-13
Abstract: Cannulation of the diminutive ascending aorta in small neonates can be difficult. Not only can this result in narrowing of the aorta once the cannula is removed and the aortotomy closed, but the cannula itself may obstruct the aorta before and after cardiopulmonary bypass. This may contribute to unstable hemodynamics and complicate the process of weaning from bypass at the conclusion of the procedure.In order to overcome these difficulties, we have utilized an alternative means of aortic cannulation which is both simple and reproducible. Furthermore, it has potential benefits for the patient in the perioperative period. We termed this "Simplified Aortic Cannulation" (SAC) and presented our initial experience with SAC at international meetings in September 2004 and 2005 [1]. This has become our standard aortic cannulation technique for neonates requiring reconstruction of the ascending aorta or transverse aortic arch and for those neonates and small infants with small (less than 5 mm) ascending aortas.Between February 2000 and January 2006, 86 neonates underwent cardiac procedures utilizing SAC at the Children's Hospital of Oklahoma. These included a 1300 g preterm infant with Tetralogy of Fallot, and 2 infants with Transposition of the Great Arteries weighing less than 1800 g. Also included in this group are all neonates with Hypoplastic Left heart Syndrome (n = 57) and with Interrupted Aortic Arch complex (n = 18) operated on during this period.A standard median sternotomy is performed, and the thymus gland, if large, is partially removed. The innominate artery is dissected out cephalad to the innominate vein and looped with a vessel loop. This is usually done prior to the opening of the pericardium. A Castaneda clamp is applied and a longitudinal arteriotomy is made. A 3.5 mm thin-walled PTFE graft is anastomosed end-to-side to the innominate artery using a continuous 7/0 prolene suture. The innominate artery is unclamped and the graft is flushed and clamped and l
Double shunt technique for hybrid palliation of hypoplastic left heart syndrome: a case report
Marcelo Jatene, Patrícia M Oliveira, Rafael A Moysés, Ieda Jatene, Carlos A Pedra, Simone F Pedra, Fabiana Succi, Vitor Carvalho, Carlos R Ferreiro
Journal of Cardiothoracic Surgery , 2011, DOI: 10.1186/1749-8090-6-146
Abstract: Different surgical techniques for hybrid procedure for hypoplastic left heart syndrome (HLHS) have being described [1]. Taking into account local fibrosis or tissue friability during second stage operation, the possibility of aortic arch obstruction related to stent deployment and surgical difficulty in management of distal ductal stented area must be considered [2-5].Caldarone [6] reported an alternative solution to palliate HLHS, with pulmonary artery (PA) to innominate artery shunt, associated to bilateral pulmonary artery banding (PAB), patent ductus arteriosus stenting and atrioseptostomy, not avoiding future events related to the stent.The purpose of this case report is to describe a new technique to palliate HLHS with banding PA branches, without patent ductus arteriosus stent, but with a double shunt from PA to ascending and descending aorta by combined thoracotomies. This new technique provides adequate flow to aortic arch and descending aorta, avoiding patent ductus arteriosus stenting, and, eventually, future problems with patent ductus arteriosus stent removing.The operation is performed by 2 combined approaches: 1. median sternotomy and 2. left thoracotomy. Cardiopulmonary Bypass is not used. By median sternotomy, right and left PAB with 3.0 mm Polytetrafluoroethylene bands are performed.After heparin infusion (2 mg/kg), a reverse Blalock-Taussig shunt with 4 mm Polytetrafluoroethylene graft is performed from proximal PA to inomminate artery. After that, a 7 mm Polytetrafluoroethylene graft is anastomosed in the left side of proximal PA, directed towards left pleura (Figure 1).Distal edge of the graft is closed and placed inside left pleura. Chest is drained and closed. The child is then repositioned and left 4th intercostal space is opened; the Polytetrafluoroethylene graft is identified and anastomosed with descending aorta (Figure 2).A 3.5 kg white female, 30 days old, was admitted; prostaglandin E-1 was initiated, after diagnosis, with 22 days of li
Modelling single ventricle physiology: Review of engineering tools to study first stage palliation of hypoplastic left heart syndrome  [PDF]
Giovanni Biglino,Tain-Yen Hsia,Richard Figliola,Silvia Schievano
Frontiers in Pediatrics , 2013, DOI: 10.3389/fped.2013.00031
Abstract: First stage palliation of hypoplastic left heart syndrome, i.e., the Norwood operation, results in a complex physiological arrangement, involving different shunting options (modified Blalock-Taussig, RV-PA conduit, central shunt from the ascending aorta) and enlargement of the hypoplastic ascending aorta. Engineering techniques, both computational and experimental, can aid in the understanding of the Norwood physiology and their correct implementation can potentially lead to refinement of the decision-making process, by means of patient-specific simulations. This paper presents some of the available tools that can corroborate clinical evidence by providing detailed insight into the fluid dynamics of the Norwood circulation as well as alternative surgical scenarios (i.e., virtual surgery). Patient-specific anatomies can be manufactured by means of rapid prototyping and such models can be inserted in experimental set-ups (mock circulatory loops) that can provide a valuable source of validation data as well as hydrodynamic information. Such models can be tuned to respond to differing the patient physiologies. Experimental set-ups can also be compatible with visualization techniques, like particle image velocimetry and cardiovascular magnetic resonance, further adding to the knowledge of the local fluid dynamics. Multi-scale computational models include detailed three-dimensional (3D) anatomical information coupled to a lumped parameter network representing the remainder of the circulation. These models output both overall hemodynamic parameters while also enabling to investigate the local fluid dynamics of the aortic arch or the shunt. As an alternative, pure lumped parameter models can also be employed to model Stage 1 palliation, taking advantage of a much lower computational cost, albeit missing the 3D anatomical component. Finally, analytical techniques, such as wave intensity analysis, can be employed to study the Norwood physiology, providing a mechanistic perspective on the ventriculo-arterial coupling for this specific surgical scenario.
Analysis of the Arabic Broken Plural and Diminutive  [PDF]
George A. Kiraz
Computer Science , 1995,
Abstract: This paper demonstrates how the challenging problem of the Arabic broken plural and diminutive can be handled under a multi-tape two-level model, an extension to two-level morphology.
Breakup of diminutive Rayleigh jets  [PDF]
Wim van Hoeve,Stephan Gekle,Jacco H. Snoeijer,Michel Versluis,Michael P. Brenner,Detlef Lohse
Physics , 2010, DOI: 10.1063/1.3524533
Abstract: Discharging a liquid from a nozzle at sufficient large velocity leads to a continuous jet that due to capillary forces breaks up into droplets. Here we investigate the formation of microdroplets from the breakup of micron-sized jets with ultra high-speed imaging. The diminutive size of the jet implies a fast breakup time scale $\tau_\mathrm{c} = \sqrt{\rho r^3 / \gamma}$ of the order of 100\,ns{}, and requires imaging at 14 million frames per second. We directly compare these experiments with a numerical lubrication approximation model that incorporates inertia, surface tension, and viscosity [Eggers and Dupont, J. Fluid Mech. 262, 205 (1994); Shi, Brenner, and Nagel, Science 265, 219 (1994)]. The lubrication model allows to efficiently explore the parameter space to investigate the effect of jet velocity and liquid viscosity on the formation of satellite droplets. In the phase diagram we identify regions where the formation of satellite droplets is suppressed. We compare the shape of the droplet at pinch-off between the lubrication approximation model and a boundary integral (BI) calculation, showing deviations at the final moment of the pinch-off. Inspite of this discrepancy, the results on pinch-off times and droplet and satellite droplet velocity obtained from the lubrication approximation agree with the high-speed imaging results.
Dissecting aneurysm of arch and descending thoracic aorta presenting as a left sided hemorrhagic pleural effusion  [cached]
Shamim Shelley,Thakur Sumitra,Sengupta Amitava,Bhattacharyya Sujit
Lung India , 2010,
Abstract: The most common cause of massive hemorrhagic effusion is malignancy. Herein we present a case of dissecting aneurysm of descending thoracic aorta presenting initially with shortness of breath due to left sided massive pleural effusion. Effusion was hemorrhagic in nature with high hematocrit value. CT scan of thorax with CT angiogram was done and that revealed the diagnosis.
Novel SMAD3 Mutation in a Patient with Hypoplastic Left Heart Syndrome with Significant Aortic Aneurysm  [PDF]
Kristi K. Fitzgerald,Abdul Majeed Bhat,Katrina Conard,James Hyland,Christian Pizarro
Case Reports in Genetics , 2014, DOI: 10.1155/2014/591516
Abstract: Aneurysms-osteoarthritis syndrome (AOS) caused by haploinsufficiency of SMAD3 is a recently described cause of syndromic familial thoracic aortic aneurysm and dissection (TAAD). We identified a novel SMAD3 mutation in a patient with hypoplastic left heart syndrome (HLHS) who developed progressive aortic aneurysm requiring surgical replacement of the neoaortic root, ascending aorta, and proximal aortic arch. Family screening for the mutation revealed that his father, who has vascular and skeletal features of AOS, and his brother, who is asymptomatic, also have the pathogenic mutation. This is the first case report of a SMAD3 mutation in a patient with hypoplastic left heart syndrome. This case highlights the importance of genetic testing for known causes of aneurysm in patients with congenital heart disease who develop aneurysmal disease as it may significantly impact the management of those patients and their family members. 1. Introduction Familial thoracic aortic aneurysm can be divided into syndromic and nonsyndromic forms. While abdominal aortic aneurysm generally occurs sporadically, thoracic aortic aneurysm and dissection (TAAD) is inherited in an autosomal dominant manner with decreased penetrance and variable expression [1]. The genes causing syndromic and nonsyndromic forms of TAAD encode proteins that compose the structural components associated with connective tissue, key members of the TGF-β signaling pathway, or components of the contractile unit of smooth muscle cells. The genetic etiology of nonsyndromic causes of familial TAAD is largely unknown; however, several genes including, MYH11, ACTA2, and MYLK have been implicated [2–4]. The genetic cause of syndromic forms of TAAD include FBN1, the cause of Marfan syndrome, SLC2A10, the cause of arterial tortuosity syndrome, and TGFβR1, TGFβR2, and the recent identification of TGFβ2, all of which cause Loeys-Dietz syndrome [5–9]. In 2011 SMAD3, was shown to cause a new syndromic form of thoracic aortic aneurysm and dissection. The features of this condition included early onset osteoarthritis in the majority of patients and the authors proposed the name aneurysms-osteoarthritis syndrome (AOS) [10]. In addition to aneurysm and dissection, early osteoarthritis, and other systemic findings, congenital heart disease including persistent ductus arteriosus, atrial septal defect, pulmonary valve stenosis, atrial fibrillation, and bicuspid aortic valve have also been observed in patients with defects in SMAD3 [11]. SMAD3 encodes an intracellular member of the TGF-β signaling pathway that activates or
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