Does Maintenance of Pulmonary Blood Flow Pulsatility at the Time of the Fontan Operation Improve Hemodynamic Outcome in Functionally Univentricular Hearts?

It is unclear whether residual anterograde pulmonary blood flow (APBF) at the time of Fontan is beneficial. Pulsatile pulmonary flow may be important in maintaining a compliant and healthy vascular circuit. We, therefore, wished to ascertain whether there was hemodynamic evidence that residual pulsatile flow at time of Fontan promotes clinical benefit. 106 consecutive children with Fontan completion (1999-2018) were included. Pulmonary artery pulsatility index (PI, (systolic pressure-diastolic pressure)/mean pressure)) was calculated from preoperative cardiac catheterization. Spectral analysis charted PI as a continuum against clinical outcome. The population was subsequently divided into three pulsatility subgroups to facilitate further comparison. Median PI prior to Fontan was 0.236 (range 0-1). 39 had APBF, in whom PI was significantly greater (median: 0.364 vs. 0.177, Mann-Whitney p < 0.0001). There were four early hospital deaths (3.77%), and PI in these patients ranged from 0.214 to 0.423. There was no correlation between PI and standard cardiac surgical outcomes or systemic oxygen saturation at discharge. Median follow-up time was 4.33 years (range 0.0273-19.6), with no late deaths. Increased pulsatility was associated with higher oxygen saturations in the long term, but there was no difference in reported exercise tolerance (Ross), ventricular function, or atrioventricular valve regurgitation at follow-up. PI in those with Fontan-associated complications or the requiring pulmonary vasodilators aligned with the overall population median. Maintenance of pulmonary flow pulsatility did not alter short-term outcomes or long-term prognosis following Fontan although it tended to increase postoperative oxygen saturations, which may be beneficial in later life.

Microscopic determination of correlations in the fluid interfacial region in the presence of liquid-gas asymmetry.

In a recent article, we showed how the properties of the density-density correlation function and its integral, the local structure factor, in the fluid interfacial region, in systems with short-ranged forces, can be understood microscopically by considering the resonances of the local structure factor [A. O. Parry and C. Rascón, Nat. Phys. 15, 287 (2019)NPAHAX1745-247310.1038/s41567-018-0361-z]. Here, we illustrate, using mean-field square-gradient theory and the more microscopic Sullivan density functional model, and how this approach generalizes when there is liquid-gas asymmetry, i.e., when the bulk correlation lengths of the coexisting liquid and gas phases are different. In particular, we are able to express the correlation function exactly as a simple average of contributions arising from two effective Ising-symmetric systems referred to as the symmetric gas and symmetric liquid. When combined with our earlier results, this generates analytical approximations for the correlation function and the local structure factor, which are near indistinguishable from the numerical solution to the Ornstein-Zernike equations over the whole range of wave vectors. Our results highlight how asymmetry affects the correlation function structure and describes the crossover from a long-ranged Goldstone mode to short-ranged properties determined by the local density as the wave vector increases.

Correlation-function structure in square-gradient models of the liquid-gas interface: Exact results and reliable approximations.

In a recent article, we described how the microscopic structure of density-density correlations in the fluid interfacial region, for systems with short-ranged forces, can be understood by considering the resonances of the local structure factor occurring at specific parallel wave vectors q [Nat. Phys. 15, 287 (2019)1745-247310.1038/s41567-018-0361-z]. Here we investigate this further by comparing approximations for the local structure factor and pair correlation function against three new examples of analytically solvable models within square-gradient theory. Our analysis further demonstrates that these approximations describe the pair correlation function and structure factor across the whole spectrum of wave vectors, encapsulating the crossover from the Goldstone mode divergence (at small q) to bulklike behavior (at larger q). As shown, these approximations are exact for some square-gradient model potentials and never more than a few percent inaccurate for the others. Additionally, we show that they describe very accurately the correlation function structure for a model describing an interface near a tricritical point. In this case, there are no analytical solutions for the correlation functions, but the approximations are nearly indistinguishable from the numerical solutions of the Ornstein-Zernike equation.

Implications of shunt morphology for the surgical management of extrahepatic portosystemic shunts.

OBJECTIVE: To describe the implications of extrahepatic portosystemic shunt morphology for the chosen site of shunt closure in dogs and cats. METHODS: A retrospective review of a consecutive series of dogs and cats managed for congenital extrahepatic portosystemic shunts. RESULTS: In total, 54 dogs and 10 cats met the inclusion criteria, revealing five distinct shunt types: left gastrophrenic, right gastrocaval (types Ai, Aii and Aiii), splenocaval, colocaval and left gastro-azygos. Without exception, findings of computed tomography angiography and direct gross observations at the time of surgery confirmed four consistent sites of communication between the anomalous shunting vessel and the systemic venous system: the caudal vena cava at the level of the epiploic foramen; the left phrenic vein at the level of the oesophageal hiatus; the azygos vein at the level of the aortic hiatus; and the caudal vena cava or iliac vein at the level of the 6th or 7th lumbar vertebrae. The use of intraoperative mesenteric portography was effective for confirming that at the time of surgery all portal tributary vessels were proximal to the point of shunt attenuation. CONCLUSIONS: Findings confirmed that for the common types of extrahepatic portosystemic shunts there were only four consistent sites of communication between the shunt and the systemic venous system. This information supports the use of a systematic approach for the location and attenuation of shunts in dogs and cats.

Post-temporary ligation intraoperative mesenteric portovenography: comparison with CT angiography for investigation of portosystemic shunts.

OBJECTIVES: Comparison of pre-operative CT angiography and post-temporary, full-ligation, intraoperative, mesenteric portovenography for the characterisation of intrahepatic portal vasculature in patients with single extrahepatic portosystemic shunts. METHODS: Descriptive analysis of previously collected images from 14 dogs and five cats. RESULTS: With the exception of shunts involving the right gastric vein, intrahepatic arborisation appeared similar on both modalities. Portovenography improved contrast enhancement and slightly enlarged the intrahepatic portal vasculature. CLINICAL SIGNIFICANCE: CT angiography cannot replace intraoperative mesenteric portovenography after temporary full ligation, which provides information on intrahepatic portal vascularity. It is a practical and dynamic procedure, providing results that are instantaneously available at the time of surgery. In addition, intraoperative post-temporary, full-ligation, mesenteric portography confirmed that the single shunting vessel had both been recognised and ligated.

Successful treatment of a metastatic, gastrointestinal stromal tumour in a dog with toceranib phosphate (Palladia).

A ten-year-old, female-entire English springer spaniel presented with a large intra-abdominal mass but no other clinical signs. Gastrointestinal stromal tumour of the caecum with widespread abdominal metastasis was confirmed. Treatment with toceranib phosphate resulted in complete response, despite the absence of exon-8 or exon-11 c-kit mutation. There was no clinical evidence of tumour recurrence nine months after diagnosis.

Comparison of computed tomographic angiography and intraoperative mesenteric portovenography for extrahepatic portosystemic shunts.

OBJECTIVES: Comparison of intra-operative mesenteric portovenography and computed tomographic angiography for the documentation of the portal vasculature in patients with single extrahepatic portosystemic shunts. METHODS: Retrospective study of patients with extrahepatic portosystemic shunts that underwent preoperative computed tomographic angiography and intra-operative mesenteric portography. Studies were compared for identification of the intra- and extrahepatic portal vasculature. RESULTS: Computed tomographic angiography demonstrated all four portal vein tributaries and sub-tributaries. Intra-operative mesenteric portography inconsistently demonstrated the cranial mesenteric vein, the gastroduodenal vein (12 of 49 dogs and 0 of 10 cats), splenic vein (46 of 49 dogs and 8 of 10 cats) and caudal mesenteric vein (3 of 49 dogs and 2 of 10 cats). Computed tomographic angiography showed the intrahepatic portal vein with shunts emanating from the left gastric vein, splenocaval shunts or shunts involving the left colic vein. It showed intrahepatic portal branching in 5 of 12 patients with shunts involving the right gastric vein. Intra-operative mesenteric portography showed the intrahepatic portal vein in 29 of 59 patients but was outperformed by computed tomographic angiography in all cases except those patients with a shunt involving the right gastric vein. CLINICAL SIGNIFICANCE: In cases that have undergone diagnostic preoperative computed tomographic angiography there is no indication for diagnostic intra-operative mesenteric portovenography before ligation. In contrast, portovenography performed "after" temporary full ligation of the shunt provides clinical useful information and might be considered an integral investigation during shunt attenuation surgery.

Challenging cognitive cases among physician populations: case vignettes and recommendations.

BACKGROUND: Physicians are not immune to cognitive impairment. Because of the risks created by practising doctors with these issues, some have suggested developing objective, population-specific measures of evaluation and screening guidelines to assess dysfunction. However, there is very little published information from which to construct such resources. AIMS: To highlight the presentation characteristics and provide evaluation recommendations specific to the needs of physicians with actual or presumed cognitive impairment. METHODS: A retrospective database and chart review of cognitively impaired doctors who presented to a physician health programme (PHP). Complex cases were highlighted using simple descriptives and clinical vignettes. RESULTS: A total of 124 cases were included. Clients presented with a variety of issues other than cognitive concerns. We identified four principal domains of impairment: (i) diseases of (or in) the brain (48%); (ii) mood/ anxiety disorders or treatment side effects (28%); (iii) substance use (9%) and (iv) traumatic brain injury (7%). Age was not a good predictor of impairment and brief screening using the Montreal Cognitive Assessment demonstrated a ceiling effect with this cohort. Although many clients underwent some type of professional or personal transition, impairment did not necessarily indicate worse functioning after care. CONCLUSIONS: Physician cognitive evaluations should consider a variety of secondary sources of information, particularly vocational performance reports. It may take time before cognitive impairment can be diagnosed or ruled-out in this population. Prior assumptions, especially for non-cognitive referrals, can lead to inaccurate diagnosis and referrals. PHPs must manage cognitive cases carefully, not only in their clinical complexity but also in their psychosocial aspects.

Morphology of congenital portosystemic shunts involving the left colic vein in dogs and cats.

OBJECTIVE: To describe the anatomy of congenital portosystemic shunts involving the left colic vein in dogs and cats. METHODS: Retrospective review of a consecutive series of dogs and cats managed for congenital portosystemic shunts. For inclusion a shunt involving the left colic vein with recorded intraoperative mesenteric portovenography or computed tomography angiography along with direct gross surgical observations at the time of surgery was required. RESULTS: Six dogs and three cats met the inclusion criteria. All cases had a shunt which involved a distended left colic vein. The final communication with a systemic vein was variable; in seven cases (five dogs, two cats) it was via the caudal vena cava, in one cat it was via the common iliac vein and in the remaining dog it was via the internal iliac vein. In addition, two cats showed caudal vena cava duplication. CLINICAL SIGNIFICANCE: The morphology of this shunt type appeared to be a result of an abnormal communication between either the left colic vein or the cranial rectal vein and a pelvic systemic vein (caudal vena cava, common iliac vein or internal iliac vein). This information may help with surgical planning in cases undergoing shunt closure surgery.

Morphology of splenocaval congenital portosystemic shunts in dogs and cats.

OBJECTIVE: To describe the anatomy of congenital portosystemic shunts involving the splenic vein communicating with the caudal vena cava at the level of the epiploic foramen. MATERIALS AND METHODS: A retrospective review of a consecutive series of dogs and cats managed for congenital portosystemic shunts. RESULTS: Ninety-eight dogs and eight cats met the inclusion criteria of a congenital portosystemic shunt involving the splenic vein communicating with the prehepatic caudal vena cava plus recorded intra-operative mesenteric portovenography or computed tomography angiography and gross observations at surgery. All cases (both dogs and cats) had a highly consistent shunt that involved a distended gastrosplenic vein that communicated with the caudal vena cava at the level of the epiploic foramen via an anomalous left gastric vein. CLINICAL SIGNIFICANCE: The morphology of the shunt type described appeared to be a result of an abnormal communication between the left gastric vein and the caudal vena cava and the subsequent development of preferential blood flow through an essentially normal portal venous system. The abnormal communication (shunt) was through the left gastric vein and not the splenic vein, as might have been expected. This information may help with surgical planning in cases undergoing shunt closure surgery.

Liquid-gas asymmetry and the wave-vector-dependent surface tension.

Attempts to extend the capillary-wave theory of fluid interfacial fluctuations to microscopic wavelengths, by introducing an effective wave-vector (q)-dependent surface tension σeff(q), have encountered difficulties. There is no consensus as to even the shape of σeff(q). By analyzing a simple density functional model of the liquid-gas interface, we identify different schemes for separating microscopic observables into background and interfacial contributions. In order for the backgrounds of the density-density correlation function and local structure factor to have a consistent and physically meaningful interpretation in terms of weighted bulk gas and liquid contributions, the background of the total structure factor must be characterized by a microscopic q-dependent length ζ(q) not identified previously. The necessity of including the q dependence of ζ(q) is illustrated explicitly in our model and has wider implications; i.e., in typical experimental and simulation studies, an indeterminacy in ζ(q) will always be present, reminiscent of the cutoff used in capillary-wave theory. This leads inevitably to a large uncertainty in the q dependence of σeff(q).

Morphology of congenital portosystemic shunts involving the right gastric vein in dogs.

OBJECTIVE: To describe the anatomy of congenital portosystemic shunts involving the right gastric vein in dogs. MATERIALS AND METHODS: Retrospective review of a consecutive series of dogs managed for congenital portosystemic shunt. RESULTS: Twenty-two dogs met the inclusion criteria of a congenital portosystemic shunt involving the right gastric vein with recorded intraoperative mesenteric portovenography or computed tomography angiography and gross observations at the time of surgery. Of these, 20 (91%) had a shunt that entered the pre-hepatic caudal vena cava at the level of the epiploic foramen and two (9%) had a shunt that entered the post-hepatic caudal vena cava at the level of the diaphragm. Shunts entering the pre-hepatic caudal vena cava could be further classified into three consistent subdivisions. CLINICAL SIGNIFICANCE: The morphology of each shunt type described appeared to be a result of an abnormal communication between the left gastric vein and the caudal vena cava, the presence or absence of an abnormal communication between the splenic, left gastric and portal veins and the subsequent development of preferential blood flow through essentially normal portal vessels within the portal venous system. The abnormal communication (shunt) was through the left gastric vein and not the right gastric vein, as might have been expected. This information may help with surgical planning in cases undergoing shunt closure surgery.

Transcatheter and endovascular stent graft management of coarctation-related pseudoaneurysms.

OBJECTIVE: Surgical correction of congenital aortic coarctation can lead to a number of important problems including late pseudoaneurysm formation. Redo surgery has a significant risk. Endovascular stent graft repair is increasingly used but there are limited data regarding this indication. We describe the experience of two UK congenital referral centres. DESIGN: Retrospective analysis of patients treated with endovascular aortic stent grafting for late pseudoaneurysms. SETTING: Two UK congenital heart centres, Bristol Heart Institute and Leeds General Infirmary. PATIENTS: 17 patients were treated 2006-2012. This represents all patients treated with this technique. MAIN OUTCOME MEASURES: Procedural and postprocedure success and complications. RESULTS: The average time from index repair to endovascular repair of pseudoaneurysm was 24.6 years. The majority (70.6%) had patch aortoplasty as the original surgical procedure and 41.2% were not under follow-up or discharged. Stent grafting procedural success rate was 100%. Median hospital stay postprocedure was 3 days. There was no procedural mortality or immediate complication. There were four minor early and three minor late complications. Imaging follow-up was available for an average of 31.6 months (range 6-65 months). All patients have demonstrated positive remodelling of the pseudoaneurysm with no incidence of continued expansion or stent graft failure up to 5 years following implant. CONCLUSIONS: Endovascular stent graft treatment of pseudoaneurysms show promising results in a population who have a high risk of surgical re-intervention. Complication rates appear to be low and recovery is quick. Longer-term data remain essential to scrutinise stent graft performance in this situation.

Morphology of congenital portosystemic shunts emanating from the left gastric vein in dogs and cats.

OBJECTIVE: To describe the anatomy of congenital portosystemic shunts emanating from the left gastric vein in dogs and cats. METHODS: A retrospective review of a consecutive series of dogs and cats managed for congenital portosystemic shunts. RESULTS: Forty-six dogs and 27 cats met the inclusion criteria of a congenital portosystemic shunt emanating from the left gastric vein. Of the 46 dogs, 28 (61%) had a shunt that entered the left phrenic vein, 10 (22%) had a shunt that entered the post hepatic caudal vena cava and in 8 (17%) the shunt entered the azygos vein. Of the 27 cats, 19 (70%) had a shunt that entered the left phrenic vein and 8 (30%) had a shunt that entered the post hepatic caudal vena cava. CLINICAL SIGNIFICANCE: The systemic vein into which the shunt entered was consistent showing three common presentations: left gastro-phrenic, left gastro-caval and left gastro-azygos. This information may help with surgical planning in cases undergoing shunt closure surgery.

Mixing behavior of the biosurfactant, rhamnolipid, with a conventional anionic surfactant, sodium dodecyl benzene sulfonate.

The use of small angle neutron scattering, SANS, neutron reflectivity, NR, and surface tension to study the mixing properties of the biosurfactant rhamnolipid with a conventional anionic surfactant, sodium dodecyl 6-benzene sulfonate, LAS, is reported. The monorhamnose rhamnolipid, R1, mixes close to ideally with LAS at the air-water interface, whereas for mixtures of LAS with the dirhamnose rhamnolipid, R2, the LAS strongly partitions to the air-water interface relative to R2, probably because of the steric hindrance of the larger R2 headgroup. These trends in the binary mixtures are also reflected in the ternary R1/R2/LAS mixtures. However, for these ternary mixtures, there is also a pronounced synergy in the total adsorption, which reaches a maximum for a LAS/rhamnolipid mole ratio of about 0.6 and a R1/R2 mol ratio of about 0.5, an effect which is not observed in the binary mixtures. In solution, the R1/LAS mixtures form relatively small globular micelles, L(1), at low surfactant concentrations (<20 mM), more planar structures (lamellar, L(α), unilamellar/multilamellar vesicles, ulv/mlv) are formed at higher surfactant concentrations for R1 and LAS rich compositions, and a large mixed phase (L(α)/L(1) and L(1)/L(α)) region forms at intermediate surfactant compositions. In contrast, for the R2/LAS mixtures, the higher preferred curvature of R2 dominates the phase behavior. The predominant microstructure is in the form of small globular micelles, except for solution compositions rich in LAS (>80 mol % LAS) where more planar structures are formed. For the ternary mixtures, there is an evolution in the resulting phase behavior from one dominated by L(1) (R2 rich) to one dominated by planar structures, L(α), (R1, LAS rich), and which strongly depends upon the LAS/rhamnolipid and R1/R2 mole ratio.

[Sensory ataxic neuromyelopathy in acquired copper deficiency]. / Ataxie proprioceptive et carence en cuivre masquée.

INTRODUCTION: Neurological involvement associated with copper deficiency has been reported recently in humans and may be under-recognized. CASE REPORT: A 65-year-old patient, with past history of gastrectomy 40 years earlier, developed a myelodysplastic syndrome and then subacute onset of progressive gait ataxia and paresthesias in the lower extremities. Serum vitamin B12 level was low but neurological deterioration persisted, despite vitamin replacement therapy and normal cobalamin level. Further diagnostic investigations revealed severe copper deficiency. Copper supplementation led to hematologic improvement and neurological stabilization. CONCLUSION: Copper and vitamin B12 deficiency, due to malabsorption as a cause of progressive neuromyelopathy and hematologic manifestations, may coexist.

Estimation of renal function and its potential impact on carboplatin dosing in children with cancer.

Renal function-based carboplatin dosing is used routinely in paediatric oncology clinical practice. It is important that accurate assessments of renal function are carried out consistently across clinical centres, a view supported by recently published British Nuclear Medicine Society (BNMS) guidelines for measuring glomerular filtration rate (GFR). These guidelines recommend the use of a radioisotope method for GFR determination, with between two and five blood samples taken starting 2 h after radioisotope injection and application of the Brochner-Mortensen (BM) correction factor. To study the likely impact of these guidelines, we have investigated current practices of measuring GFR in all 21 Children's Cancer and Leukaemia Group (CCLG) paediatric oncology centres in the United Kingdom. This information was used to evaluate the potential impact on renal function-based carboplatin dosing using raw 51Cr-EDTA clearance data from 337 GFR tests carried out in children with cancer. A questionnaire survey revealed that between two and four samples were taken after isotope administration, with BM and Chantler corrections used in 38% (8/21) and 28% (6/21) of centres, respectively. A change from Chantler to BM correction, based on the BNMS guidelines, would result in a > 10% decrease in carboplatin dose in at least 15% of patients and a > 25% decrease in 2% of patients. A greater proportion of patients would have an alteration in carboplatin dose when centres not using any correction factor implement the BM correction. The increase in estimated 51Cr-EDTA half-life observed by omitting the I h sample decreases carboplatin dose by > 10% in 23-52% of patients and by > 25% in 3% of patients. This study highlights current variations in renal function measurement between clinical centres and the potential impact on carboplatin dosing. A standard methodology for estimating GFR should be followed to achieve uniform dosing in children with cancer.

Intrusion of fluids into nanogrooves: how geometry determines the shape of the gas-liquid interface.

We study the shape of gas-liquid interfaces forming inside rectangular nanogrooves (i.e., slit-pores capped on one end). On account of purely repulsive fluid-substrate interactions the confining walls are dry (i.e., wet by vapor) and a liquid-vapor interface intrudes into the nanogrooves to a distance determined by the pressure (i.e., chemical potential). By means of Monte Carlo simulations in the grand-canonical ensemble (GCEMC) we obtain the density rho(z) along the midline (x = 0) of the nanogroove for various geometries (i.e., depths D and widths L) of the nanogroove. We analyze the density profiles with the aid of an analytic expression which we obtain through a transfer-matrix treatment of a one-dimensional effective interface Hamiltonian. Besides geometrical parameters such as D and L , the resulting analytic expression depends on temperature T , densities of coexisting gas and liquid phases in the bulk rho g,l(x) and the interfacial tension gamma. The latter three quantities are determined in independent molecular dynamics simulations of planar gas-liquid interfaces. Our results indicate that the analytic formula provides an excellent representation of rho(z) as long as L is sufficiently small. At larger L the meniscus of the intruding liquid flattens. Under these conditions the transfer-matrix analysis is no longer adequate and the agreement between GCEMC data and the analytic treatment is less satisfactory.