Normal growth and intravascular volume status with good metabolic control during peritoneal dialysis in infancy

The most demanding patient population on peritoneal dialysis (PD) consists of children under 2 years of age. Their growth is inferior to that of older children and maintaining euvolemia is difficult, especially in anuric patients. In this prospective study reported here, we enrolled 21 patients <2 years of age (mean 0.59 years) at onset of PD and monitored their uremia parameters and evaluated their nutrition. Since no good instrument currently exists for estimating intravascular volume status, we used traditional blood pressure measurements, echocardiography, and N-terminal atrial natriuretic peptide measurements. Growth was compared with midparental height. Metabolic control was good. Long-term hypertension was seen in 43% of the patients, but left ventricular hypertrophy decreased during the study period. Mean weekly urea Kt/V was 3.38 ± 0.66 and creatinine clearance was 49 ± 20 L/week per 1.73 m². Catch-up growth was documented in 57% of the patients during PD. However, these children did not attain their midparental height at the end of PD at a mean age of 1.71 years. Although favorable metabolic control and good growth were achieved during PD, these children lagged in term of their midparental height. We conclude that several instruments are needed for determining the management of intravascular volume status and that the control of calcium–phosphorus status is demanding.     

Differential efficacies of somatostatin receptor agonists for G-protein activation and desensitization of somatostatin receptor subtype 4-mediated responses

Both the histamine H1-receptor (H1R) and H2-receptor (H2R) exhibit pronounced species selectivity in their pharmacological properties; i.e., bulky agonists possess higher potencies and efficacies at guinea pig (gp) than at the corresponding human (h) receptor isoforms. In this study, we examined the effects of NG-acylated imidazolylpropylguanidines substituted with a single phenyl or cyclohexyl substituent on H1R and H2R species isoforms expressed in Sf9 insect cells. N1-(3-Cyclohexylbutanoyl)-N2-[3-(1H-imidazol-4-yl)propyl]guanidine (UR-AK57) turned out to be the most potent hH2R agonist identified so far (EC50 of 23 nM in the GTPase assay at the hH2R-Gsalpha fusion protein expressed in Sf9 insect cells). UR-AK57 was almost a full-hH2R agonist and only slightly less potent and efficacious than at gpH2R-Gsalpha. Several NG-acylated imidazolylpropylguanidines showed similar potency at hH2R and gpH2R. Most unexpectedly, UR-AK57 exhibited moderately strong partial hH1R agonism with a potency similar to that of histamine, whereas at gpH1R, UR-AK57 was only a very weak partial agonist. Structure/activity relationship studies revealed that both the alkanoyl chain connecting the aromatic or alicyclic substituent with the guanidine moiety and the nature of the carbocycle (cyclohexyl versus phenyl ring) critically determine the pharmacological properties of this class of compounds. Collectively, our data show that gpH1R and gpH R do not necessarily exhibit preference for bulky agonists (2) compared with hH1R and hH2R, respectively, and that UR-AK57 is a promising starting point for the development of both potent and efficacious hH1R and hH2R agonists.     

Automatic ventricular threshold measurement in children with epicardial pacing leads

BACKGROUND: The aim of the study was to evaluate the safety and reliability of automatic ventricular pacing threshold measurement, the Medtronic Capture Management (CM), in children with epicardial pacing leads. CM has not been recommended for use with epicardial leads due to lack of pertinent data. METHODS: During a 2-year study period, 34 children (mean age 6.1 years, range 0 days to 17.7 years) with epicardial leads were prospectively enrolled. The CM measurements were compared with in-office ventricular pacing threshold measurements. Thirty bipolar and five unipolar epicardial leads were assessed. RESULTS: CM measurements were successful and reliable in 30 out of 35 leads (86%). The mean threshold with CM was 1.16 V (95% CI 1.07-1.26 V), and with standard measurement was 1.18 V (95% CI 1.09-1.28 V), at a pulse width of 0.40 ms. The reasons for failure were evoked response undersensing in two cases (5.7%), and high intrinsic rate in one case. High pacing thresholds prevented accurate CM measurements in two cases. CONCLUSIONS: CM automatic threshold measurements are consistent with standard ventricular pacing threshold measurements in children with epicardial leads. We recommend a period of monitoring CM performance before programming it to adjust output according to automatic threshold measurements, in order to find the patients in whom it does not work. The CM feature provides increased pacing safety when it measures well (86% of leads). A larger study is needed to prove the tendency for extending battery life in children with epicardial leads.     

Accuracy of computer-aided measurements in endovascular stent-graft planning: an experimental study with two phantoms

RATIONALE AND OBJECTIVES: The aim of this study was to evaluate the accuracy of the new measurement software, created for aortic stent-graft planning. The software finds semiautomatically the centerline of the vessel from computer tomographic angiography data and calculates semiautomatically diameters and lengths. MATERIALS AND METHODS: Two phantoms were constructed, scanned by CT and measured with the measurement software. Results were compared with the known dimensions of the phantoms and mean fractional errors were calculated. Linear regression analysis was also made between measured and known diameters. RESULTS: The mean fractional error (+/- SD) for all diameter measurements combined was 0.017 +/- 0.011. In the linear regression analysis, was 1.000. For length measurements, the mean fractional error (+/- SD) was 0.009 +/- 0.0006. CONCLUSIONS: The software enables accurate measurements perpendicular or parallel to the semiautomatically created centerline path.     

Cardiac surgery productivity and throughput improvements

PURPOSE: The high variability in cardiac surgery length--is one of the main challenges for staff managing productivity. This study aims to evaluate the impact of six interventions on open-heart surgery operating theatre productivity. DESIGN/METHODOLOGY/APPROACH: A discrete operating theatre event simulation model with empirical operation time input data from 2603 patients is used to evaluate the effect that these process interventions have on the surgery output and overtime work. A linear regression model was used to get operation time forecasts for surgery scheduling while it also could be used to explain operation time. FINDINGS: A forecasting model based on the linear regression of variables available before the surgery explains 46 per cent operating time variance. The main factors influencing operation length were type of operation, redoing the operation and the head surgeon. Reduction of changeover time between surgeries by inducing anaesthesia outside an operating theatre and by reducing slack time at the end of day after a second surgery have the strongest effects on surgery output and productivity. A more accurate operation time forecast did not have any effect on output, although improved operation time forecast did decrease overtime work. RESEARCH LIMITATIONS/IMPLICATIONS: A reduction in the operation time itself is not studied in this article. However, the forecasting model can also be applied to discover which factors are most significant in explaining variation in the length of open-heart surgery. PRACTICAL IMPLICATIONS: The challenge in scheduling two open-heart surgeries in one day can be partly resolved by increasing the length of the day, decreasing the time between two surgeries or by improving patient scheduling procedures so that two short surgeries can be paired. ORIGINALITY/VALUE: A linear regression model is created in the paper to increase the accuracy of operation time forecasting and to identify factors that have the most influence on operation time. A simulation model is used to analyse the impact of improved surgical length forecasting and five selected process interventions on productivity in cardiac surgery.     

Endovascular treatment of peripheral aneurysms of the posterior inferior cerebellar artery

BACKGROUND AND PURPOSE: Peripheral aneurysms of the posterior inferior cerebellar artery (PICA) are rare, and pre-existing literature concerning their endovascular treatment is limited. The purpose of this study was to assess the etiology and clinical characteristics of peripheral PICA aneurysms and to evaluate the angiographic and clinical results of the patients who underwent endovascular treatment for a peripheral PICA aneurysm in a single center.MATERIALS AND METHODS: Twelve consecutive patients with 12 peripheral PICA aneurysms (10 ruptured) included in an internal data base were retrospectively reviewed. Posttreatment and follow-up angiograms were analyzed, and the clinical outcome was recorded.RESULTS: The etiology was dissection in 7 (58%) and unknown in 5 cases (42%). Three dissecting aneurysms reruptured before endovascular treatment, and another 3 demonstrated angiographic progress. Four aneurysms were treated by endosaccular coiling, 6 (all dissecting) by parent artery occlusion, and in 2 cases endovascular treatment failed. Angiographic outcome was complete aneurysm and/or parent artery occlusion in 9 cases and neck remnant in 1 case. One aneurysm needed retreatment at follow-up. One lethal procedural complication occurred, and transient ischemic symptoms appeared in 2 patients. The clinical outcome was good in 7 patients, whereas 3 patients, all poor clinical grade, died (1 for unrelated reasons). No rebleedings have occurred during the follow-up.CONCLUSION: In this series, most peripheral PICA aneurysms were secondary to arterial dissection. They were unstable with a high risk of rebleeding and a high mortality if not treated without delay. Endovascular treatment was effective in preventing rehemorrhage.

Posterior inferior cerebellar artery (PICA) aneurysms account for approximately 0.5% to 3.0% of all intracranial aneurysms,^1,2 and most are located right at the origin or in the first anteromedullary segment of the vessel.^2-4 Roughly, only a fifth of the PICA aneurysms are thought to arise from more distal segments of the PICA.^2-4 Approximately 28% of all aneurysms located in the vertebrobasilar arteries, including PICA, have been estimated to be of dissecting origin.⁵ Among peripheral PICA aneurysms, dissecting etiology has been found in 0%-80% of the cases.^6-9Due to anatomic location of the PICAs (proximity to brain stem and lower cranial nerves), their surgical treatment is associated with significant risk of neurologic complications.¹⁰ Endovascular technique enables treating these lesions without craniotomy and the risks related to surgical manipulation. Despite the recently increased number of publications, the pre-existing literature concerning endovascular treatment of peripheral PICA aneurysms is limited and controversial.^6-9,11-21 In the present study, a consecutive series of 12 patients harboring a peripheral PICA aneurysm allocated for endovascular treatment in a single center was retrospectively analyzed.     

Atresia of proximal coronary arteries in pulmonary atresia with intact ventricular septum - fetal and neonatal findings

Pulmonary atresia with intact ventricular septum (PA+IVS) is a rare congenital cardiac malformation which is associated with ventriculocoronary arterial communications from the right ventricle. We present a case of PA+IVS with a bilateral atresia of the coronary ostia, and thus, a completely right ventricular-dependent coronary circulation followed up by fetal echocardiography. Eventually the infant died of myocardial infarction at 2 days of age.