Computational fluid dynamics simulations as a complementary study for transcatheter endovascular stent implantation for re-coarctation of the aorta associated with minimal pressure drop: an aneurysmal ductal ampulla with aortic isthmus narrowing.

BACKGROUND: Transcatheter stent implantation has been employed to treat re-coarctation of the aorta in adolescents and young adults. The aim of this work is to use computational fluid dynamics to characterise haemodynamics associated with re-coarctation involving an aneurysmal ductal ampulla and aortic isthmus narrowing, which created minimal pressure drop, and to incorporate computational fluid dynamics's findings into decision-making concerning catheter-directed treatment. METHODS: Computational fluid dynamics permits numerically solving the Navier-Stokes equations governing pulsatile flow in the aorta, based on patient-specific data. We determined flow-velocity fields, wall shear stresses, oscillatory shear indices, and particle stream traces, which cannot be ascertained from catheterisation data or magnetic resonance imaging. RESULTS: Computational fluid dynamics showed that, as flow entered the isthmus, it separated from the aortic wall, and created vortices leading to re-circulating low-velocity flow that induced low and multidirectional wall shear stress, which could sustain platelet-mediated thrombus formation in the ampulla. In contrast, as flow exited the isthmus, it created a jet leading to high-velocity flow that induced high and unidirectional wall shear stress, which could eventually undermine the wall of the descending aorta. SUMMARY: We used computational fluid dynamics to study re-coarctation involving an aneurysmal ductal ampulla and aortic isthmus narrowing. Despite minimal pressure drop, computational fluid dynamics identified flow patterns that would place the patient at risk for: thromboembolic events, rupture of the ampulla, and impaired descending aortic wall integrity. Thus, catheter-directed stenting was undertaken and proved successful. Computational fluid dynamics yielded important information, not only about the case presented, but about the complementary role it can serve in the management of patients with complex aortic arch obstruction.

Left Pulmonary Artery Occlusion Following Device Closure of Patent Ductus Arteriosus in Premature Infants.

Background: Device closure of a patent ductus arteriosus (PDA) is rapidly evolving, with the Amplatzer Piccolo Occluder (Abbott) receiving US Food and Drug Administration approval and becoming the first device approved for PDA closure in patients ≥700 g. We report on the first known cases of complete left pulmonary artery (LPA) occlusion following Piccolo closure of a PDA in premature infants. Methods: Retrospective chart analysis of PDA closures. Results: We have performed over 50 cases of Piccolo device closure of the PDA in preterm neonates in the past 2 years, with these 2 cases representing our only complications (4%). This represents a total complication rate similar to or lower than most centers that have published data for this procedure. Conclusions: Although rare, severe LPA obstruction can be seen in premature infants following device closure of the PDA. The Piccolo device is designed to ideally remain entirely intraductal. Although our device selection appeared to provide a device short enough for the given ductal length, we recommend, whenever possible, giving consideration to using the shortest possible device. We also recommend increasing the frequency of echocardiographic surveillance to weekly studies if at any time the imaging demonstrates an increase in the degree of obstruction/turbulence.

Transcatheter Exclusion of a Large Pseudoaneurysm of a Systemic Right Ventricular Outflow Tract.

We describe a rare patient with a large pseudoaneurysm of the right ventricular outflow tract that had developed after placement of a right ventricle-pulmonary artery conduit. A 7-mm Amplatzer Septal Occluder device was used to exclude the pseudoaneurysm, allowing for safer subsequent surgical repair. (Level of Difficulty: Advanced.).

Endovascular Repair of Thoracic Aortic Pseudoaneurysms in Children.

Pediatric aortic pseudoaneurysms are rare and can result in life-threatening sequelae. We describe 2 cases of exclusion of descending thoracic aortic pseudoaneurysm by different approaches, chosen based on the anatomy and cause of the lesions. (Level of Difficulty: Beginner.).

Anomalous origin of the left coronary artery from the right pulmonary artery.

Anomalous origin of the left coronary artery (LCA) from the pulmonary artery (ALCAPA) is a rare congenital anomaly, one which requires a high index of suspicion in order to be diagnosed promptly and managed accurately. ALCAPA from the right branch pulmonary artery (RPA) is a small subset of ALCAPA in general, with only a few reported cases in the world literature. We report two cases of ALCAPA from the RPA: the first case, an infant, presented in severe cardiac failure requiring preoperative extracorporeal membrane oxygenation (ECMO) for stabilization; and the second, a neonate, presented with severe aortic coarctation (CoA). Both patients underwent successful complete surgical repair using a modified surgical technique, and are doing well in midterm follow-up. We describe our operative technique and review the literature of this rare congenital anomaly.

Individualized approach to the surgical treatment of tetralogy of Fallot with pulmonary atresia.

BACKGROUND: Tetralogy of Fallot with pulmonary atresia is a heterogeneous group of defects, characterised by diverse sources of flow of blood to the lungs, which often include multiple systemic-to-pulmonary collateral arteries. Controversy surrounds the optimal method to achieve a biventricular repair with the fewest operations while basing flow to the lungs on the native intrapericardial pulmonary arterial circulation whenever possible. We describe an individualized approach to this group of patients that optimizes these variables. METHODS: Over a consecutive 10-year period, we treated 66 patients presenting with tetralogy of Fallot and pulmonary atresia according to the source of the pulmonary arterial flow. Patients were grouped according to whether the flow of blood to the lungs was derived exclusively from the intrapericardial pulmonary arteries, as seen in 29 patients, exclusively from systemic-to-pulmonary collateral arteries, as in 5 patients, or from both the intrapericardial pulmonary and collateral arteries, as in the remaining 32 patients. We divided the latter group into 9 patients deemed simple, and 23 considered complex, according to whether the pulmonary arterial index was greater than or less than 90 millimetres squared per metre squared, and whether the number of collateral arteries was less than or greater than 2, respectively. RESULTS: We achieved complete biventricular repair in 58 patients (88%), with an overall mortality of 3%. Repair was accomplished in a single stage in all patients without systemic-to-pulmonary collateral arteries, but was staged, with unifocalization, in the patients lacking intrapericardial pulmonary arteries. Complete repair without unifocalization was achieved in all patients with the simple variant of the mixed morphology, and in 56% of patients with the complex variant. The average number of procedures per patient to achieve complete repair was 1, 2.2, 3.8, and 2.6 in patients with exclusively native intrapericardial, simple and mixed, complex and mixed and exclusively collateral pulmonary arterial flow, respectively. CONCLUSIONS: An individualized approach based on the morphology of the pulmonary arterial supply permits achievement of a high rate of complete intracardiac repairs, basing pulmonary arterial flow on the intrapericardial pulmonary arteries in the great majority of cases, and has a low rate of reoperation and mortality.

Cerebral regional oxygenation during aortic coarctation repair in pediatric population.

OBJECTIVE: During repair of aortic coarctation, clamping of the transverse aortic arch proximal to the left common carotid artery occludes blood flow to the left carotid and vertebral arteries. The objective of the present study is to determine whether blood flow through the right carotid and vertebral arteries provides adequate cerebral blood flow during aortic cross-clamping, as assessed by near-infrared spectroscopy. METHODS: In 11 consecutive children undergoing aortic coarctation repair through a standard posterolateral thoracotomy, regional cerebral oxygen saturation (cSO(2)) was measured using near-infrared spectroscopy. Six patients underwent an extended end-to-end repair, in which the aortic cross-clamp was placed in between the innominate and left common carotid arteries (extended repair group). Five patients underwent a standard end-to-end repair in which the cross-clamp was clamp placed between the left common carotid and subclavian arteries (standard repair group). RESULTS: After aortic clamping, there was a significant decrease in cSO(2) in the extended repair group, whereas the cSO(2) increased in the standard repair group (-9.2+/-12.2 vs 6.0+/-5.1%, extended vs standard repair groups, p=0.03). In the extended repair group, the cSO(2) decreased linearly during the aortic cross-clamping period (r(S)=-0.842, p<0.001), while in the standard repair group, the cSO(2) increased during the same time period (r(S)=0.786, p<0.001). Regression analysis identified the site of aortic cross-clamping as the sole independently significant variable explaining changes in the cSO(2) during aortic cross-clamping (p<0.03), whereas neither age nor duration of aortic cross-clamping was statistically significant. There were no postoperative neurological impairments in either group of patients. CONCLUSION: During aortic coarctation repair, aortic cross-clamping proximal, as compared to distal, to the left carotid artery is associated with significantly decreased regional cerebral oxygen saturation, as measured by near-infrared spectroscopy. Although no short-term clinical impairments were identified, long-term follow-up in a larger cohort is needed to study the effects of unbalanced cerebral oxygenation during clamping of the transverse arch. These data suggest that cerebral saturation monitoring is warranted, and may be indicative of cerebral hypoperfusion.

Intrafamilial variability of noncompaction of the ventricular myocardium.

BACKGROUND: Noncompaction of the ventricular myocardium (NVM) is a relatively uncommon form of cardiomyopathy characterized by a highly trabeculated myocardium. This report describes the clinical and genetic evaluation of a 3-generation kindred. METHODS: Family members were initially evaluated by 2-dimensional echocardiography. Most family members with signs of NVM were further evaluated by magnetic resonance imaging. Genetic analyses included mutational screening of the taffazin (TAZ) and alpha-dystrobrevin (DTNA) genes. RESULTS: Eight family members had signs of NVM. Considerable interindividual variation was noted in terms of spatial distribution and severity of affected regions and ventricular dysfunction. Depending on which of 2 previously proposed quantitative diagnostic criteria were used and where ventricular myocardial measurements were taken, between 4 and 7 of these individuals had findings that were considered diagnostic. Magnetic resonance imaging served as a useful adjunct for confirming or establishing diagnoses in all 8 individuals. No mutation was found in TAZ or DTNA. CONCLUSIONS: This kindred demonstrates the remarkably wide phenotypic spectrum that can be seen in familial cases of NVM, ranging from prenatal/neonatal lethality to a complete lack of symptoms. The fact that all 8 affected individuals either have shown improvement in ventricular function or symptoms during childhood or have been asymptomatic indicates that NVM can have a relatively benign course. The degree and nature of cardiac involvement are also quite varied, and there is a weak correlation with ventricular function and symptoms. Evaluation of families with NVM requires careful assessment that uses a combination of imaging techniques and diagnostic criteria.

Noncompaction syndrome of the myocardium: pathophysiology and imaging pearls.

Patients with noncompaction syndrome of the myocardium may present with cardiac arrhythmia, thromboembolic events, or left ventricular failure. Associations with other diseases, including neurologic or other cardiac syndromes, have been noted. Noncompaction syndrome of the myocardium is primarily diagnosed by echocardiography; however, CT scanning and magnetic resonance imaging are useful tools for determining severity and the patient's prognosis. With these methods, high-resolution images of the myocardium are obtained that enable better recognition of the areas over which the trabeculae are distributed. Early diagnosis can improve the patient's survival by premature heart transplantation or implantation of a defibrillator. Also, as there are many reports of occurrence of this syndrome in several members of the same family (mainly X-linked inheritance), upon accurate and early diagnosis, the patient's family can be further screened.

Percutaneous stent placement in children weighing less than 10 kilograms.

The objectives of this study were to evaluate the safety, efficacy, and outcomes of palliative percutaneous stent placement in infants with congenital heart disease (CHD). There is interest in improving outcomes of infants with CHD through interventional/surgical collaboration. Small, high-risk patients may benefit from delayed open operations, and endovascular stents may provide a means to defer surgery to more advantageous times in select infants. Patients weighing < or =10 kg in whom stent placement was attempted during 2003-2006 were identified. Diagnoses, indications, angiographic and hemodynamic data, complications, and outcomes were reviewed. Seventeen stents were successfully placed in 15 patients. The mean age was 10.21 months; the mean weight was 6.08 kg. Indications were branch pulmonary artery stenosis, coarctation, total anomalous pulmonary venous return with obstructed venous egress, right ventricle-pulmonary artery conduit, and shunt stenosis. Premounted Palmaz Genesis and Driver Mx stents were used. Average vessel diameter increased from 3.65 to 6.72 mm (p < 0.001). The pressure gradient fell from 24 to 15 mm Hg (p < 0.01). Two stents migrated. One was recaptured and implanted at the target site and one implanted away from the target site. None needed surgical intervention. Mean follow-up was 270 days. Five patients have had additional surgery; seven patients underwent 10 additional stent dilations. There was no procedural-related mortality. Five patients (33%) died during the follow-up period, none attributable to the stent placement. We conclude that stent placement can be successfully accomplished in select, small, high-risk patients. A collaborative interventional/surgical paradigm is important to ensure that the risk-benefit ratio is properly evaluated during the patient selection.

Systemic to pulmonary venous shunt: imaging findings and clinical presentations.

Multislice computed tomography technology has enabled sophisticated insights into the evaluation of collateral venous pathways in the thorax. A small but well-established body of literature has described the multiple venous pathways in patients with central venous obstruction. In unusual circumstances, however, physiologically maladaptive pathways have been described involving systemic to pulmonary venous shunts. This paper describes 21 patients with systemic to pulmonary venous shunts having a wide spectrum of etiologies. Clinical presentations typically include cardiopulmonary symptomatology and paradoxical emboli. Ultrafast magnetic resonance and multislice computed tomography established the diagnosis of this uncommon but important entity.

Preoperative palliation of newborn obstructed total anomalous pulmonary venous connection by endovascular stent placement.

Patients with obstructed total anomalous pulmonary venous connection (TAPVC) usually present critically ill and continue to be extremely challenging with presurgical stabilization. We present an extra corporeal membrane oxygenation (ECMO)-dependent neonate with obstructed TAPVC that was successfully palliated with transvenous stent placement in the obstructed vertical vein.

Intra-atrial tissue plasminogen activator infusion for prosthetic valve thrombosis.

Thrombosis is a well-known and life-threatening complication of prosthetic mechanical valves. Therapy typically requires medical thrombolysis or surgical thrombectomy/valve replacement. We report the case of a thrombosed atrioventricular valve in a young boy with complex congenital heart disease, which was successfully treated with direct intra-atrial infusion of recombinant tissue plasminogen activator after failed attempts at systemic therapy. We present this treatment as an alternative to conventional medical therapy.

Evaluation of right ventricular fibrosis in adult congenital heart disease using gadolinium-enhanced magnetic resonance imaging: initial experience in patients with right ventricular loading conditions.

OBJECTIVE: Gadolinium-enhanced cardiac magnetic resonance imaging has been used to show myocardial fibrosis, a finding that appears as late gadolinium enhancement. Its role in the evaluation of right ventricular fibrosis in congenital heart disease is unclear. The purpose of this study was to demonstrate late gadolinium enhancement of the right ventricle in adult and adolescent congenital heart disease and to investigate the relationship between this enhancement and clinical and pathophysiological data. DESIGN: In total, 24 patients, 16 patients with congenital heart disease and right ventricular loading conditions and 8 controls, underwent gadolinium-enhanced viability imaging. Diagnoses varied and included repaired, palliated, and unrepaired lesions. The presence and extent of right ventricular late gadolinium enhancement was compared with patient clinical and hemodynamic data. Exact Wilcoxon tests, Fisher's exact tests, and Spearman's rank correlation were used to compare variables. RESULTS: Nine of 16 patients (56%) were found to have right ventricular late gadolinium enhancement, ranging from 5% to 80% of right ventricular myocardium affected (mean 36.1%, SD 29.7). The combination of right ventricular systolic pressure >or=98 mm Hg and systemic oxygen saturation

Perfusion abnormalities in congenital and neoplastic pulmonary disease: comparison of MR perfusion and multislice CT imaging.

The aim of this work was to assess magnetic resonance (MR) perfusion patterns of chronic, non-embolic pulmonary diseases of congenital and neoplastic origin and to compare the findings with results obtained with pulmonary, contrast-enhanced multislice computed tomography (CT) imaging to prove that congenital and neoplastic pulmonary conditions require MR imaging over the pulmonary perfusion cycle to successfully and directly detect changes in lung perfusion patterns. Twenty-five patients underwent concurrent CT and MR evaluation of chronic pulmonary diseases of congenital (n=15) or neoplastic (n=10) origin. Analysis of MR perfusion and contrast-enhanced CT datasets was realized by defining pulmonary and vascular regions of interest in corresponding positions. MR perfusion calculated time-to-peak enhancement, maximal enhancement and the area under the perfusion curve. CT datasets provided pulmonary signal-to-noise ratio measurements. Vessel center-lines of bronchial arteries were determined. Underlying perfusion type, such as pulmonary arterial or systemic arterial supply, as well as regions with significant variations in perfusion were determined statistically. Analysis of the pulmonary perfusion pattern detected pulmonary arterial supply in 19 patients; six patients showed systemic arterial supply. In pulmonary arterial perfusion, MR and multislice CT imaging consistently detected the perfusion type and regions with altered perfusion patterns. In bronchial arterial supply, MR perfusion and CT imaging showed significant perfusion differences. Patients with bronchial arterial supply had bronchial arteries ranging from 2.0 to 3.6 mm compared with submillimeter diameters in pulmonary arterial perfusion. Dynamic MR imaging of congenital and neoplastic pulmonary conditions allowed characterization of the pulmonary perfusion type. CT imaging suggested the presence of systemic arterial perfusion by visualizing hypertrophied bronchial arteries.

Endovascular stent implantation in patients with stenotic aortoarteriopathies: early and medium-term results.

Data regarding stent implantation for stenotic aortoarteriopathy (SAA) are incomplete. We report on nine patients with this rare syndrome who underwent arterial stent implantation. Indications, results, and complications for patients with SAA were reviewed. Nine patients underwent 11 procedures. Twenty-two stents were implanted in the aorta or brachiocephalic vessels. Five patients had diffuse stenoses, three patients had middle aortic syndrome, and one patient had thoracic and abdominal coarctation. Associated diagnoses included Williams syndrome (2), neurofibromatosis (2), Takayasu's (1), and congenital rubella (1). Median gradient was 60 mm Hg (20-140 mm Hg). Poststent gradient was 15 mm Hg (0-60 mm Hg; P < 0.001). Additional stents were implanted in two patients and five underwent stent redilation. Two patients (22%) were found to have aneurysm formation. Stent implantation effectively provides gradient relief in SAA. Gradient reduction persists or is amenable to redilation. Importantly, however, uncomplicated stent implantation does not preclude aneurysm formation and may be more common than in traditional patient groups.

Cardiomyopathy in Coffin-Lowry syndrome.

Coffin-Lowry syndrome (CLS) is a rare but well-documented X-linked disorder characterized by small size, developmental delay/mental retardation, and characteristic facial and skeletal findings in affected males. The phenotype in affected females is far more variable and can include developmental differences, obesity, and characteristic facial and skeletal differences. Cardiac anomalies are reported in less than 20% of affected males, with cardiomyopathy being one of the rare but reported complications of this disorder. However, cardiomyopathy is not well characterized in CLS. Here, we report on a 14-year-old boy with physical and developmental findings consistent with CLS who presented with a relatively sudden onset of signs of congestive heart failure due to a restrictive cardiomyopathy; an endomyocardial biopsy demonstrated non-specific hypertrophic myocyte alterations consistent with cardiomyopathy. This is the first description of the histology and electron microscopy of cardiomyopathy in CLS.