Successful transcatheter occlusion of an anomalous pulmonary vein with dual drainage to the left atrium

We describe a case of a scimitar syndrome "variant" where dual drainage existed from the right upper and middle pulmonary veins to the inferior vena cava and left atrium. Device closure of the anomalous vein at the level of the connection to the IVC was successful in achieving diversion of pulmonary venous flow to the left atrium. Vigilance during work-up of anomalous pulmonary venous drainage (whether isolated or associated with other cardiac defects that may be amenable to device closure) is important to define the presence of dual connections to the left atrium, in which case a less-invasive transcatheter approach may be feasible.

Neuroimaging and obesity: current knowledge and future directions

Neuroimaging is becoming increasingly common in obesity research as investigators try to understand the neurological underpinnings of appetite and body weight in humans. Positron emission tomography (PET), functional magnetic resonance imaging (fMRI) and magnetic resonance imaging (MRI) studies examining responses to food intake and food cues, dopamine function and brain volume in lean vs. obese individuals are now beginning to coalesce in identifying irregularities in a range of regions implicated in reward (e.g. striatum, orbitofrontal cortex, insula), emotion and memory (e.g. amygdala, hippocampus), homeostatic regulation of intake (e.g. hypothalamus), sensory and motor processing (e.g. insula, precentral gyrus), and cognitive control and attention (e.g. prefrontal cortex, cingulate). Studies of weight change in children and adolescents, and those at high genetic risk for obesity, promise to illuminate causal processes. Studies examining specific eating behaviours (e.g. external eating, emotional eating, dietary restraint) are teaching us about the distinct neural networks that drive components of appetite, and contribute to the phenotype of body weight. Finally, innovative investigations of appetite-related hormones, including studies of abnormalities (e.g. leptin deficiency) and interventions (e.g. leptin replacement, bariatric surgery), are shedding light on the interactive relationship between gut and brain. The dynamic distributed vulnerability model of eating behaviour in obesity that we propose has scientific and practical implications.

Workplace abuse and economic exploitation of children working in the streets of Latin American cities

This study presents the prevalence of, and factors associated with workplace abuse and economic exploitation among 584 children ages 5 to 17 working in the streets of the Latin American cities of Bogotá, Lima, Quito, and São Paulo. Each additional 10 hours/week of children's work in the streets increased workplace abuse prevalence by 8% (odds ratio [OR], 1.08; 95% confidence interval [95% CI], 1.01-1.19). Suffering an occupational injury was associated with abuse (OR, 1.70; 95% CI, 1.13-2.57). Participation in begging was associated with an almost five-fold increase in economic exploitation (OR, 4.94; 95% CI, 1.96-12.48). Children residing with their mothers were 2.6 times more likely to experience economic exploitation (OR, 2.61; 95% CI, 1.58-4.33), reflecting our definition of economic exploitation in which a child's income is confiscated by parents, even if used for basic family needs. Increased health care coverage and conditional cash transfer programs are recommended to improve the situation.

Effects of Epinephrine and Norepinephrine on Serum Parathyroid Hormone and Calcium in Normal Subjects

Infusions with stepwise increasing concentrations of epinephrine (from 2.5 to 10 micrograms/min) and norepinephrine (0.5-2.0 micrograms/min) were given to normal subjects. During infusion of epinephrine there was a clear rise of the serum parathyroid hormone (PTH) levels already at the lowest concentration. Concomitantly there was a fall in the serum concentrations of calcium. The PTH levels returned to baseline promptly after termination of infusion whereas hypocalcaemia persisted up to 30 minutes, indicating a primary response of PTH to epinephrine. When propranolol was given prior to and during the epinephrine infusion no significant changes occurred for either PTH or calcium. During infusion of norepinephrine no consistent significant changes were noted for either PTH or serum calcium. Thus, our data do not support any concept of a basal adrenergic tone which normally modulates the secretion of PTH. However, during conditions of stress the beta-adrenergic stimulation night be of importance.

Effects of secretin on parathyroid hormone and calcium in normal subjects, patients with hyperparathyroidism and patients with gastrinoma

In vitro studies have demonstrated that secretin can stimulate the release of parathyroid hormone (PTH), but reports concerning its effects on PTH and calcium in vivo are contradictory. To examine this question further, a bolus injection of secretin (75 IU) was given to 12 normal subjects and 10 patients with primary hyperparathyroidism (HPT). Six of the patients had multiple endocrine neoplasia and five had endocrine pancreatic tumours (EPT). Three normocalcaemic patients with EPT were also included in the study. The mean serum gastrin level rose significantly (from 19 to 40 pmol/l, p less than 0.01) within 15 min of secretin injection in the normal subjects. HPT patients without EPT had a somewhat higher mean basal level of gastrin (39 pmol/l, p less than 0.05 compared with controls), but it did not increase significantly after the secretin bolus. In six EPT patients the gastrin concentrations rose by more than 300 pmol/l. Although secretin had a biological capacity to release gastrin, it had no discernible effects on either serum PTH or serum calcium in any of the groups studied. Nor were any changes in PTH or calcium observed when secretin was given as a continuous infusion (3 IU/kg/h) over 90 min. Thus, our data do not support the concept that secretin, in vivo, is a secretagogue of PTH.

Clodronate treatment in patients with malignancy-associated hypercalcemia

The possibility of reducing symptomatic hypercalcemia and of maintaining total serum calcium concentrations less than 2.8 mmol/l with clodronate (dichloromethylene bisphosphonate) was evaluated in 28 patients with various types of malignant tumors. Four episodes of hypercalcemic crisis with mean serum calcium concentrations of 4.43 mmol/l were controlled within 4-6 days of intravenous clodronate (4 mg/kg BW/day). This was accompanied by a moderate increase in serum creatinine values which, however, returned to pretreatment levels after therapy withdrawal in all but one case. Oral clodronate successfully reduced a mean serum calcium concentration of 3.16 mmol/l in 22 out of 25 patients after 3-12 days (800-3,200 mg/day). After reversal of the hypercalcemias oral clodronate controlled the serum calcium concentration for up to 42 weeks in six out of 15 patients After discontinuation of initial therapy five of seven recurrent hypercalcemias were successfully treated with oral or intravenous clodronate. Hypocalcemia and subjective side-effects were uncommon. It is concluded that clodronate is a valuable clinical tool in the management of patients with malignancy-associated hypercalcemia.

Comparison of polyethylene tibial insert damage from in vivo function and in vitro wear simulation

Function and wear of total knee arthroplasties were compared by analysis of damage patterns on polyethylene tibial inserts retrieved from patients (Group R) with inserts obtained after in vitro force-controlled knee joint wear simulation. Two simulator input profiles were evaluated, including standard walking (Group W), and combined walking and stair descent (Group W + S), simulating varied activities and a more severe physiological environment. Damage regions on all inserts were quantitatively assessed. On average, inserts in all groups had internally rotated damage patterns and the greatest articular deformation in the lateral compartment. These patterns were more pronounced in Group W + S compared to Group W. Deformation rates of simulated inserts were analogous to about six years of physiologic function. However, both groups of simulated inserts generally underestimated the magnitude of damage area and extent observed on retrieved inserts, consistent with differences in the simulator's tibiofemoral contact mechanics and those known to occur in patients during functional activities. Modification of simulator inputs, such as the increased anteroposterior excursion and more severe loading conditions in Group W + S, can generate greater wear volume, larger damage areas, and increased surface deformation rates compared to standard inputs.

Biomechanical testing of unstable humeral shaft fracture plating

This study compared the biomechanical performance of 4.5-mm limited-contact dynamic compression plates (DCPs) and 3.5-mm locking compression plates (LCPs) for the fixation of unstable humeral shaft fractures. Composite humeri were divided into two groups: 3.5-mm LCPs and 4.5-mm DCPs. Osteotomy gaps of 5 mm, simulating diaphyseal comminution, were created. Stiffness tests were performed in anterior-posterior (AP) bending, medial-lateral (ML) bending, torsion, and axial compression. Results showed that while construct stiffnesses in ML bending and torsional loading are significantly higher for the 4.5 DCP group (p < .05), no statistically significant differences were observed in AP bending or axial compression. Fatigue characteristics under cyclic AP bending conditions were also evaluated, although no failures occurred. Data from the literature suggest that stiffness results for the LCP constructs perhaps afford sufficient fixation strength capable of supporting the physiologic loads most commonly applied during postoperative rehabilitation. However, results indicate that the DCP construct is mechanically advantageous for stabilizing diaphyseal comminuted fractures.

Percutaneous ultrasound-guided stenting of the atrial septum in fetal sheep

OBJECTIVES

Hypoplastic left heart syndrome (HLHS) with a restricitive foramen ovale is associated with high mortality related to fetal left atrial hypertension. Fetal atrial balloon septoplasty has largely failed to achieve adequate decompression due to the small size of the holes produced. We attempted to produce larger atrial communications by stenting the atrial septum in fetal sheep using a minimally invasive technique.

METHODS

We used a percutaneous, ultrasound-guided transpulmonary or transhepatic approach to attempt deployment of coronary stents (2-5 mm in diameter and 13-23 mm in length) in the atrial septum primum of 10 normal fetal sheep.

RESULTS

Coronary stents were deployed in eight of the 10 fetal sheep (119-139 days' gestation). The transhepatic route was unsuccessful (n = 2). Transpulmonary implantation was only possible in prone fetuses, so three initially supine fetuses underwent external version. Small coronary stents (2.0-2.5 mm in diameter) were deployed rapidly without complication via an 18G needle (n = 4). Larger coronary stents (5 mm in diameter) were delivered through a 4F sheath, but a right pleural effusion occurred in three of the four cases, related to inferior vena cava injury by the balloon. One stent dislodged from a floppy septum. Another was partially occluded within a week by endocardial cells.

CONCLUSIONS

Percutaneous ultrasound-guided deployment of coronary stents into the septum primum is feasible without laparotomy or uterine exteriorization in fetal sheep. Partial luminal occlusion by rapid proliferation of endocardial cells is a concern.

Successful percutaneous treatment of anomalous left coronary artery from pulmonary artery

Anomalous origin of the left main coronary artery from the pulmonary artery (ALCAPA) is an uncommon congenital condition seen in the adult population, with most patients developing symptoms in infancy. We describe successful closure of an ALCAPA in an adult using a percutaneous transcatheter approach in a patient with evidence of anterior wall ischemia believed to be the consequence of myocardial steal. A 30-year-old female was noted to have continuous flow in the right ventricular septum on transthoracic echocardiography, with subsequent imaging confirming the presence of an ALCAPA. Myocardial perfusion imaging confirmed anterior wall ischemia, and as a strategy to optimize coronary perfusion pressure, the patient underwent percutaneous ALCAPA closure using an Amplatzer vascular plug. The procedure was well tolerated, with no evidence of anterior ischemia or myocardial dysfunction. Follow up perfusion imaging demonstrated no residual anterior wall ischemia. Transcatheter closure of an ALCAPA is a potentially safe and effective alternative treatment strategy in this patient population.

Transcatheter device closure of atrial septal defects in the elderly: Technical considerations and short-term outcomes

BACKGROUND

Device closure of an atrial septal defect (ASD) results in symptom-reduction, right heart remodelling and lower pulmonary artery pressures. However it is unclear if there is a chronological limit to these benefits and whether device closure is safe in elderly subjects. The aim of this study was, therefore, to assess the safety and efficacy of device closure in patients >60 years.

METHODS

Retrospective study of Amplatzer Septal Occluder device closures from a single institution (May 1999-August 2002).

RESULTS

Fifty subjects aged >60 years (range 60-85 years) had ASD device closure (27% of the total cohort). Defect size and shunt size were similar for both younger and older groups (2.2:1 in both groups, p=0.9) as were procedural duration, fluoroscopy time and device size deployed. Baseline right ventricular (RV) systolic pressure ((younger vs. older) 39 vs. 49 mmHg, p<0.001) and right ventricular size (45 vs. 51 mm, p<0.001) were greater in the older group. Following closure RV systolic pressure (49 vs. 45 mmHg, p<0.01) and RV size (51 vs. 44 mm, p=0.01) decreased in the older group.

CONCLUSION

Device closure of an ASD can be performed safely in older patients. The right heart shows signs of remodelling even in elderly subjects.

Fenestration of the Fontan circuit as treatment for plastic bronchitis

Plastic bronchitis is a rare, potentially life-threatening condition in which protein casts form within and occlude the bronchus, resulting in pulmonary failure, and has been identified as a complication after the Fontan procedure. We present a case of a 5-year-old girl who had undergone an extracardiac fenestrated Fontan repair as a component of staged palliation for tricuspid atresia. Six weeks following surgery, the patient presented with airway obstruction, coughing a bronchial cast. Medical therapies to optimize heart function and attempt to control cast formation were implemented, with little clinical impact. Following cardiac catheterization to stent open the fenestration, the symptoms of plastic bronchitis resolved. Cast expectoration recurred following spontaneous closure of the stented fenestration and again resolved with recreation of the baffle defect. Fenestration of the Fontan circuit alters hemodynamics, thereby providing an additional therapeutic option for this devastating disorder.