Respiratory motion compensation by model-based catheter tracking during EP procedures

In many cases, radio-frequency catheter ablation of the pulmonary veins attached to the left atrium still involves fluoroscopic image guidance. Two-dimensional X-ray navigation may also take advantage of overlay images derived from static pre-operative 3D volumetric data to add anatomical details otherwise not visible under X-ray. Unfortunately, respiratory motion may impair the utility of static overlay images for catheter navigation. We developed a novel approach for image-based 3D motion estimation and compensation as a solution to this problem. It is based on 3D catheter tracking which, in turn, relies on 2D/3D registration. To this end, a bi-plane C-arm system is used to take X-ray images of a special circumferential mapping catheter from two directions. In the first step of the method, a 3D model of the device is reconstructed. Three-dimensional respiratory motion at the site of ablation is then estimated by tracking the reconstructed catheter model in 3D based on bi-plane fluoroscopy. Phantom data and clinical data were used to assess model-based catheter tracking. Our phantom experiments yielded an average 2D tracking error of 1.4 mm and an average 3D tracking error of 1.1 mm. Our evaluation of clinical data sets comprised 469 bi-plane fluoroscopy frames (938 monoplane fluoroscopy frames). We observed an average 2D tracking error of 1.0 ± 0.4 mm and an average 3D tracking error of 0.8 ± 0.5 mm. These results demonstrate that model-based motion-compensation based on 2D/3D registration is both feasible and accurate.     

Respiratory motion correction for image-guided cardiac interventions using 3-D echocardiography

In this paper, we investigate the use of 3-D echocardiography (echo) data for respiratory motion correction of roadmaps in image-guided cardiac interventions. This is made possible by tracking and calibrating the echo probe and registering it to the roadmap coordinate system. We compare two techniques. The first uses only echo–echo registration to predict a motion-correction transformation in roadmap coordinates. The second combines echo–echo registration with a model of the respiratory motion of the heart. Using experiments with cardiac MRI and 3-D echo data acquired from eight volunteers, we demonstrate that the second technique is more robust than the first, resulting in motion-correction transformations that were accurate to within 5 mm in 60% of cases, compared to 42% for the echo-only technique, based on subjective visual assessments. Objective validation showed that the model-based technique had an accuracy of 3.3 ± 1.1 mm, compared to 4.1 ± 2.2 mm for the echo only technique. The greater errors of the echo-only technique were mostly found away from the area of echo coverage. The model-based technique was more robust away from this area, and also has significant benefits in terms of computational cost.     

Cardiac rehabilitation availability and delivery in Brazil: a comparison to other upper middle-income countries

BackgroundBrazil has insufficient cardiac rehabilitation capacity, yet density and regional variation in unmet need is unknown. Moreover, South America has CR guidelines, but whether delivery conforms has not been described.ObjectiveThis study aimed to establish: (1) cardiac rehabilitation volumes and density, and (2) the nature of programmes, and (3) compare these by: (a) Brazilian region and (b) to other upper middle-income countries (upper-MICs).MethodsIn this cross-sectional study, a survey was administered to cardiac rehabilitation programmes globally. Cardiac associations were engaged to facilitate programme identification. Density was computed using Global Burden of Disease study ischaemic heart disease incidence estimates. Results were compared to data from the 29 upper-MICs with cardiac rehabilitation (N = 249 programmes).ResultsCardiac rehabilitation was available in all Brazilian regions, with 30/75 programmes initiating a survey (40.0% programme response rate). There was only one cardiac rehabilitation spot for every 99 ischaemic heart disease patient. Most programmes were funded by government/hospital sources (n = 16, 53.3%), but in 11 programmes (36.7%) patients depended on private health insurance. Guideline-indicated conditions were accepted in ≥70% of programmes. Programmes had a team of 3.8 ± 1.9 staff (versus 5.9 ± 2.8 in other upper-MICs, p < 0.05), offering 4.0 ± 1.6/10 core components (versus 6.0 ± 1.5 in other upper-MICs, p < 0.01; more tobacco cessation and return-to-work counselling needed in particular) over 44.5 sessions/patient (Q25–75 = 29–65) vs. 32 sessions/patient (Q25–75 = 15–40) in other upper-MICs (p < 0.01).ConclusionBrazilian cardiac rehabilitation capacity must be augmented, but where available, services are consistent across regions, but differ from other upper-MICs in terms of staff size and core components delivered.     

Effects of the administration of 2,3-butanedione monoxime during conventional cardiopulmonary resuscitation on ischaemic contracture and resuscitability in a pig model of out-of-hospital cardiac arrest

Aim of the studyIschaemic contracture compromises the haemodynamic effectiveness of cardiopulmonary resuscitation and resuscitability. 2,3-Butanedione monoxime (BDM) reduced ischaemic contracture by inhibiting actin-myosin crossbridge formation in an isolated heart model. We investigated the effects of BDM on ischaemic contracture and resuscitation outcomes in a pig model of out-of-hospital cardiac arrest (OHCA).MethodsAfter 15 min of untreated ventricular fibrillation, followed by 8 min of basic life support, 16 pigs were randomised to receive either 2 ml kg⁻¹ of BDM solution (25 g l⁻¹) or 2 ml kg⁻¹ of saline during advanced cardiac life support (ACLS).ResultsDuring the ACLS, the control group showed an increase in left ventricular (LV) wall thickness from 10.0 mm (10.0–10.8) to 13.0 mm (13.0–13.0) and a decrease in LV chamber area from 8.13 cm² (7.59–9.29) to 7.47 cm² (5.84–8.43). In contrast, the BDM group showed a decrease in the LV wall thickness from 10 mm (9.0–10.8) to 8.5 mm (7.0–9.8) and an increase in the LV chamber area from 9.86 cm² (7.22–12.39) to 12.15 cm² (8.02–14.40). Mixed model analyses of the LV wall thickness and LV chamber area revealed significant group effects and group-time interactions. Spontaneous circulation was restored in four (50%) animals in the control group and in eight (100%) animals in the BDM group (p = 0.077). All the resuscitated animals survived during an intensive care period of 4 h.ConclusionBDM administered during cardiopulmonary resuscitation reversed ischaemic contracture in a pig model of OHCA.     

The optimum chest compression site with regard to heart failure demonstrated by computed tomography

Background

To determine the optimum chest compression site during cardiopulmonary resuscitation (CPR) with regard to heart failure (HF) by applying three-dimensional (3D) coordinates on computed tomography (CT).

Association between irisin and homocysteine in euglycemic and diabetic subjects

ObjectivesThe aim of study was to explore whether a relationship exists between homocysteine and irisin in type 2 diabetes (T2D) patients—a population with a high risk of developing cardiovascular disease—and euglycemic controls.Design and methods69 T2D patients and 75 control subjects (adjusted by body mass index (BMI)) were included in the study. Irisin and homocysteine concentrations and anthropometric and biochemical variables were determined.ResultsLevels of homocysteine were significantly higher (11.0 ± 3.0 vs 12.4 ± 4.2 μmol/l) and levels of irisin were lower (279 ± 58 vs 263 ± 38 ng/ml) in T2D patients. When both T2D and controls were considered, irisin was found to correlate only with homocysteine (r = − 0.215; p = 0.011). Moreover, a decreasing trend in irisin levels was observed according to homocysteine tertile (p = 0.034).ConclusionsOur results provide evidence of an association between irisin and homocysteine, which may be due to nicotinamide metabolism. The clinical significance of this relationship is unclear, but our findings may prompt further mechanistic research to investigate the role played by irisin in vascular disorders.     

Patient specific tumor growth prediction using multimodal images

Personalized tumor growth model is valuable in tumor staging and therapy planning. In this paper, we present a patient specific tumor growth model based on longitudinal multimodal imaging data including dual-phase CT and FDG-PET. The proposed Reaction–Advection–Diffusion model is capable of integrating cancerous cell proliferation, infiltration, metabolic rate and extracellular matrix biomechanical response. To bridge the model with multimodal imaging data, we introduce Intracellular Volume Fraction (ICVF) measured from dual-phase CT and Standardized Uptake Value (SUV) measured from FDG-PET into the model. The patient specific model parameters are estimated by fitting the model to the observation, which leads to an inverse problem formalized as a coupled Partial Differential Equations (PDE)-constrained optimization problem. The optimality system is derived and solved by the Finite Difference Method. The model was evaluated by comparing the predicted tumors with the observed tumors in terms of average surface distance (ASD), root mean square difference (RMSD) of the ICVF map, average ICVF difference (AICVFD) of tumor surface and tumor relative volume difference (RVD) on six patients with pathologically confirmed pancreatic neuroendocrine tumors. The ASD between the predicted tumor and the reference tumor was 2.4 ± 0.5 mm, the RMSD was 4.3 ± 0.4%, the AICVFD was 2.6 ± 0.6%, and the RVD was 7.7 ± 1.3%.     

The need to resume chest compressions immediately after defibrillation attempts: An analysis of post-shock rhythms and duration of pulselessness following out-of-hospital cardiac arrest

AimCurrent consensus guidelines for cardiopulmonary resuscitation (CPR) recommend that chest compressions resume immediately after defibrillation attempts and that rhythm and pulse checks be deferred until completion of 5 compression:ventilation cycles or minimally for 2 min. However, data specifically confirming the post-shock duration of asystole or pulseless electrical activity before return of spontaneous circulation (ROSC) are lacking. Our aim was to describe the frequency of the various post-shock cardiac rhythms and the duration of post-shock pulselessness in out-of-hospital non-traumatic cardiac arrest.MethodUsing prospectively-collected data from the Resuscitation Outcomes Consortium (ROC) Epistry database, the investigators reviewed monitor-defibrillator recordings of 176 patients who received defibrillation attempts in the out-of-hospital setting for ventricular fibrillation (VF) or ventricular tachycardia (VT) with absent pulses,.ResultsAmong 376 different defibrillation attempts delivered in the 176 patients, there were 182 resulting episodes of post-shock asystole. The mean interval of asystole after defibrillation was 69 ± 136 s (median 20 s; IQR 36) and the mean interval for return of an organized rhythm was 64 ± 157 s (median 7 s; IQR 26). The mean time to ROSC was 280 ± 320 s (median 136 s; IQR 445).ConclusionAfter defibrillation attempts, the majority of patients remain pulseless for over 2 min and the duration of asystole before return of pulses is longer than 120 s beyond the shock gap in as many as 25%. These data support the recommendation to immediately resume chest compressions for 2 min following attempted defibrillation.     

Twenty-four-hour profiles of urinary excretion of calcium,magnesium, phosphorus,urea, and creatinine in healthy prepubertal boys

ObjectivesAvailable data on 24-h urinary solute excretion in healthy children are sparse. We thus documented the daily and overnight variations of urinary electrolytes (calcium, magnesium, and phosphorus), urea, and creatinine in prepubertal (Tanner stage I) boys.Design and methodsNine voluntary healthy prepubertal boys aged 10.8 ± 0.11 years participated in this study. Concentrations of variables were quantified in daytime samples (collected between 07:00 h ± 30 min and 21:00 h ± 30 min) and nighttime samples (collected between 21:00 h ± 30 min and 07:00 h ± 30 min) in spring, during a period of 24-h every 3 h.ResultsSignificant differences were found between daytime and nighttime excretion of calcium (p < 0.05), magnesium (p < 0.001), phosphorus (p < 0.01), and urea (p < 0.05), with high concentrations during the night. The 24-h solute/creatinine ratio was 0.072 ± 0.008 mg/mg for calcium, 0.069 ± 0.008 mg/mg for magnesium, 0.698 ± 0.070 mg/mg for phosphorus, and 0.017 ± 0.001 g/mg for urea. Statistically significant correlation analyses showed that urea and creatinine were positively associated with body mass index (BMI) (R = 0.790, p = 0.0113 for urea; R = 0.889, p = <0.0013 for creatinine) and weight (R = 0.717, p = 0.0297 for urea; R = 0.978, p = < 0.001 for creatinine). The other urinary variables were independent of BMI and body mass.ConclusionThese data are of interest for the diagnosis of certain renal disease in prepubertal children.     

In-vitro recording of adult zebrafish heart electrocardiogram — A platform for pharmacological testing

BackgroundRecently zebrafish has become a powerful vertebrate model system for cardiac arrhythmia and another advantage is that the heart could be rapidly excised for in-vitro electrophysiological recording.MethodsWe made direct in-vitro recordings of adult zebrafish heart ECG using the microelectrode and tested the effects of various drugs on zebrafish heart ECG.ResultsThe QT interval change in the ECG was verified by optically mapped action potential duration (APD). The mean in-vitro heart rate (HR) of the adult zebrafish was 118 ± 22 beats/min. The mean QT interval was 312 ± 36 ms and mean HR corrected QT interval (QTc) 439 ± 39 ms. The mean optically mapped APD was 308 ± 30 ms, which was close to the QT interval in ECG (p = 0.815). We found that sympathomimetic drug isoproterenol increased HR, whereas L-type calcium channel blocker verapamil decreased HR. Sodium channel blocker quinidine and L-type calcium channel activator BayK8644 prolonged QTc interval in a dose-dependent manner (515 ± 24 ms and 519 ± 27 ms, respectively, both p < 0.01). The APD was also prolonged accordingly. Both rapidly and slowly activating delayed rectifier potassium channel (IKr and IKs) blockers E4031 and chromanol 293B, respectively, also prolonged QTc interval in a dose-dependent manner (523 ± 25 ms and 529 ± 27 ms, respectively, both p < 0.01). Quinidine, E4031 and chromanol 293B also decreased HR.ConclusionsDirect in-vitro recording of adult zebrafish heart is an efficient platform for test of drugs which exert electrophysiological effects on cardiomyocytes, and perturbation of ionic channels that are responsible for human long QT syndrome also modulates QT interval in adult zebrafish heart.     

Cerebral oximetry as a biomarker of postoperative delirium in cardiac surgery patients

PurposeA promising monitoring strategy for delirium is the use of cerebral oximetry, but its validity during delirium is unknown. We assessed the relationship between oximetry and delirium. We hypothesized that as cerebral oximetry values increased, delirium would resorb.Materials and methodsAn observational study was conducted with 30 consecutive adults with delirium after cardiac surgery. Oximetry, delirium assessments, and clinical data were collected for 3 consecutive days after delirium onset. Oximetry was obtained using near-infrared spectroscopy. Delirium was assessed using diagnosis, occurrence (Confusion Assessment Method-ICU), and severity scales (Delirium Index).ResultsAll patients presented delirium at entry. The mean oximetry value decreased from 66.4 ± 6.7 (mean ± SD) to 50.8 ± 6.8 on the first day after delirium onset and increased in patients whose delirium resorbed over the 3 days. The relationship between oximetry, delirium diagnosis, and severity was analyzed with a marginal model and linear mixed models. Cerebral oximetry was related to delirium diagnosis (P ≤ .0001) and severity (P ≤ .0001).ConclusionThis study highlighted the links between increased cerebral oximetry values and delirium resorption. Oximetry values may be useful in monitoring delirium progression, thus assisting in the management of this complicated condition.     

The Role of a Low-Dose Ketamine-Midazolam Regimen in the Management of Severe Painful Crisis in Patients With Sickle Cell Disease

ContextAcute pain is one of the main causes of hospital admission in sickle cell disease, with variable intensity and unpredictable onset and duration.ObjectivesWe studied the role of a low-dose intravenous (IV) ketamine-midazolam combination in the management of severe painful sickle cell crisis.MethodsA retrospective analysis was performed with data from nine adult patients who were admitted to the intensive care unit with severe painful sickle cell crises not responding to high doses of IV morphine and other adjuvant analgesics. A ketamine-midazolam regimen was added to the ongoing opioids as an initial bolus of ketamine 0.25 mg/kg, followed by infusion of 0.2–0.25 mg/kg/h. A midazolam bolus of 1 mg followed by infusion of 0.5–1 mg/h was added to reduce ketamine emergence reactions. Reduction in morphine daily requirements and improvement in pain scores were the determinants of ketamine-midazolam effect. The t-tests were used for statistical analysis.ResultsNine patients were assessed, with mean age of 27 ± 11 years. Morphine requirement was significantly lower after adding the IV ketamine-midazolam regimen. The mean ± SD IV morphine requirement (milligram/day) in the pre-ketamine day (D0) was 145.6 ± 16.5, and it was 112 ± 12.2 on Day 1 (D1) of ketamine treatment (P = 0.007). The Numeric Rating Scale scores on D0 ranged from eight to ten (mean 9.1), but improved to range from five to seven (mean 5.7) on D1. There was a significant improvement in pain scores after adding ketamine-midazolam regimen (P = 0.01).ConclusionLow-dose ketamine-midazolam IV infusion might be effective in reducing pain and opioid requirements in patients with sickle cell disease with severe painful crisis. Further controlled studies are required to prove this effect.     

Variability of the glycemic response to single food products in healthy subjects

BackgroundMany studies on the health effects of the glycemic index (GI) are confounded by differences in the intakes of other macronutrients and fibre. Little data exist about the within- and between-subject variability of the GI.ObjectiveOur objectives were therefore (i) to calculate the GI of eight commonly used food products with similar macronutrient and fibre composition, but with different sources of carbohydrates, (ii) to examine the inter- and intra-individual variability of the incremental area under the curve (iAUC) after consuming the reference solution, and (iii) to compare the effect of three different methods on 2-h postprandial blood glucose responses.DesignFour groups of 10 healthy subjects consumed in random order the increased (iGI) and decreased GI (dGI) variants and twice a glucose solution. All products consisted of 25 g available carbohydrates (CHO). For the fruit drink, glucose values were simultaneously analyzed using venous and capillary blood samples, and by using a continuous glucose monitoring system (CGMS).ResultsThe GIs for increased and decreased variants were (mean ± standard error of the mean (SEM)) 69 ± 15 and 40 ± 4 for bread, 86 ± 14 and 48 ± 8 for a fruit drink, 51 ± 12 and 20 ± 4 for cake, and 63 ± 17 and 37 ± 10 for a cookie. The inter- and intra-individual coefficient of variation (CV) of the iAUCs of the reference solution was large and varied respectively between 13 and 38%, and between 33 and 80%.ConclusionsThese data suggest that the GI is difficult to use at the individual level.     

Intra-retinal layer segmentation of 3D optical coherence tomography using coarse grained diffusion map

Optical coherence tomography (OCT) is a powerful and noninvasive method for retinal imaging. In this paper, we introduce a fast segmentation method based on a new variant of spectral graph theory named diffusion maps. The research is performed on spectral domain (SD) OCT images depicting macular and optic nerve head appearance. The presented approach does not require edge-based image information in localizing most of boundaries and relies on regional image texture. Consequently, the proposed method demonstrates robustness in situations of low image contrast or poor layer-to-layer image gradients. Diffusion mapping applied to 2D and 3D OCT datasets is composed of two steps, one for partitioning the data into important and less important sections, and another one for localization of internal layers. In the first step, the pixels/voxels are grouped in rectangular/cubic sets to form a graph node. The weights of the graph are calculated based on geometric distances between pixels/voxels and differences of their mean intensity. The first diffusion map clusters the data into three parts, the second of which is the area of interest. The other two sections are eliminated from the remaining calculations. In the second step, the remaining area is subjected to another diffusion map assessment and the internal layers are localized based on their textural similarities. The proposed method was tested on 23 datasets from two patient groups (glaucoma and normals). The mean unsigned border positioning errors (mean ± SD) was 8.52 ± 3.13 and 7.56 ± 2.95 μm for the 2D and 3D methods, respectively.     

A ventilation technique for oxygenation and carbon dioxide elimination in CPR: Continuous insufflation of oxygen at three levels of pressure in a pig model

AimPulmonary ventilation remains an important part of cardiopulmonary resuscitation, affecting gas exchange and haemodynamics. We designed and studied an improved method of ventilation for CPR, constructed specifically to support both gas exchange and haemodynamics. This method uses continuous insufflation of oxygen at three levels of pressure, resulting in tri-level pressure ventilation (TLPV). We hypothesized that TLPV improves gas exchange and haemodynamics compared to manual gold standard ventilation (GSV).MethodsIn 14 pigs, ventricular fibrillation was induced and automated CPR performed for 10 min with either TLPV or GSV. After defibrillation, CPR was repeated with the other ventilation method. Gas exchange and haemodynamics were monitored. Data are presented as mean ± standard error of the mean.ResultsTLPV was superior to GSV for PaO₂ (163 ± 36 mmHg difference; P = 0.001), and peak AWP (−20 ± 2 cmH₂O difference; P = 0.000) and higher for mean AWP (8 ± 0.2 cmH₂O difference; P = 0.000). TLPV was comparable to GSV for CPP (5 ± 3 mmHg difference; P = 0.012), VCO₂ (0.07 ± 0.3 mL/min/kg difference; P = 0.001), SvO₂ (4 ± 3%-point; P = 0.001), mean carotid flow (−0.5 ± 4 mL/min difference; P = 0.016), and pH_a (0.00 ± 0.03 difference; P = 0.002). The PaCO₂ data do not provide a conclusive result (4 ± 4 mmHg difference).ConclusionWe conclude that the ventilation strategy with a tri-level pressure cycle performs comparable to an expert, manual ventilator in an automated-CPR swine model.     

Measuring and improving cardiopulmonary resuscitation quality inside the emergency department

Aim of studyTo evaluate CPR quality during cardiac resuscitation attempts in an urban emergency department (ED) and determine the influence of the combination of scenario-based training, real-time audiovisual feedback (RTAVF), and post-event debriefing on CPR quality.MethodsCPR quality was recorded using an R Series monitor-defibrillator (ZOLL Medical) during the treatment of adult cardiac arrest patients. Phase 1 (P1; 11/01/2010-11/15/2012) was an observation period of CPR quality. Phase 2 (P2; 11/15/2012-11/08/2013) was after a 60-min psychomotor skills CPR training and included RTAVF and post-event debriefing.ResultsA total of 52 cardiac arrest patients were treated in P1 (median age 56 yrs, 63.5% male) and 49 in P2 (age 60 yrs, 83.7% male). Chest compression (CC) depth increased from 46.7 ± 3.8 mm in P1 to 61.6 ± 2.8 mm in P2 (p < 0.001), with the percentage of CC ≥ 51 mm increasing from 30.6% in P1 to 87.4% in P2 (p < 0.001). CC release velocity increased from 314 ± 25 mm/s in P1 to 442 ± 20 mm/s in P2 (p < 0.001). No significant differences were identified in CC fraction (84.3% P1 vs. 88.4% P2, p = 0.1), CC rate (125 ± 3 cpm P1 vs. 125 ± 3 cpm P2, p = 0.7), or pre-shock pause (9.7 s P1 vs. 5.9 s P2, p = 0.5), though CC fraction and pre-shock pause were within guideline recommendations.ConclusionImplementation of the bundle of scenario-based training, real-time audiovisual CPR feedback, and post-event debriefing was associated with improved CPR quality and compliance with CPR guidelines in this urban teaching emergency department.     

High resolution cortical bone thickness measurement from clinical CT data

The distribution of cortical bone in the proximal femur is believed to be a critical component in determining fracture resistance. Current CT technology is limited in its ability to measure cortical thickness, especially in the sub-millimetre range which lies within the point spread function of today’s clinical scanners. In this paper, we present a novel technique that is capable of producing unbiased thickness estimates down to 0.3 mm. The technique relies on a mathematical model of the anatomy and the imaging system, which is fitted to the data at a large number of sites around the proximal femur, producing around 17,000 independent thickness estimates per specimen. In a series of experiments on 16 cadaveric femurs, estimation errors were measured as ?0.01 ± 0.58 mm (mean ± 1 std.dev.) for cortical thicknesses in the range 0.3–4 mm. This compares with 0.25 ± 0.69 mm for simple thresholding and 0.90 ± 0.92 mm for a variant of the 50% relative threshold method. In the clinically relevant sub-millimetre range, thresholding increasingly fails to detect the cortex at all, whereas the new technique continues to perform well. The many cortical thickness estimates can be displayed as a colour map painted onto the femoral surface. Computation of the surfaces and colour maps is largely automatic, requiring around 15 min on a modest laptop computer.     

Tilting for perfusion: Head-up position during cardiopulmonary resuscitation improves brain flow in a porcine model of cardiac arrest

IntroductionCerebral perfusion is compromised during cardiopulmonary resuscitation (CPR). We hypothesized that beneficial effects of gravity on the venous circulation during CPR performed in the head-up tilt (HUT) position would improve cerebral perfusion compared with supine or head-down tilt (HDT).MethodsTwenty-two pigs were sedated, intubated, anesthetized, paralyzed and placed on a tilt table. After 6 min of untreated ventricular fibrillation (VF) CPR was performed on 14 pigs for 3 min with an automated CPR device called LUCAS (L) plus an impedance threshold device (ITD), followed by 5 min of L-CPR + ITD at 0° supine, 5 min at 30° HUT, and then 5 min at 30° HDT. Microspheres were used to measure organ blood flow in 8 pigs. L-CPR + ITD was performed on 8 additional pigs at 0°, 20°, 30°, 40°, and 50° HUT.ResultsCoronary perfusion pressure was 19 ± 2 mmHg at 0° vs. 30 ± 3 at 30° HUT (p < 0.001) and 10 ± 3 at 30° HDT (p < 0.001). Cerebral perfusion pressure was 19 ± 3 at 0° vs. 35 ± 3 at 30° HUT (p < 0.001) and 4 ± 4 at 30° HDT (p < 0.001). Brain–blood flow was 0.19 ± 0.04 ml min⁻¹ g⁻¹ at 0° vs. 0.27 ± 0.04 at 30° HUT (p = 0.01) and 0.14 ± 0.06 at 30° HDT (p = 0.16). Heart blood flow was not significantly different between interventions. With 0, 10, 20, 30, 40 and 50° HUT, ICP values were 21 ± 2, 16 ± 2, 10 ± 2, 5 ± 2, 0 ± 2, −5 ± 2 respectively, (p < 0.001), CerPP increased linearly (p = 0.001), and CPP remained constant.ConclusionDuring CPR, HDT decreased brain flow whereas HUT significantly lowered ICP and improved cerebral perfusion. Further studies are warranted to explore this new resuscitation concept.     

Statistical coronary motion models for 2D + t/3D registration of X-ray coronary angiography and CTA

Accurate alignment of intra-operative X-ray coronary angiography (XA) and pre-operative cardiac CT angiography (CTA) may improve procedural success rates of minimally invasive coronary interventions for patients with chronic total occlusions. It was previously shown that incorporating patient specific coronary motion extracted from 4D CTA increases the robustness of the alignment. However, pre-operative CTA is often acquired with gating at end-diastole, in which case patient specific motion is not available.For such cases, we investigate the possibility of using population based coronary motion models to provide constraints for the 2D + t/3D registration. We propose a methodology for building statistical motion models of the coronary arteries from a training population of 4D CTA datasets. We compare the 2D + t/3D registration performance of the proposed statistical models with other motion estimates, including the patient specific motion extracted from 4D CTA, the mean motion of a population, the predicted motion based on the cardiac shape.The coronary motion models, constructed on a training set of 150 patients, had a generalization accuracy of 1 mm root mean square point-to-point distance. Their 2D + t/3D registration accuracy on one cardiac cycle of 12 monoplane XA sequences was similar to, if not better than, the 4D CTA based motion, irrespective of which respiratory model and which feature based 2D/3D distance metric was used. The resulting model based coronary motion estimate showed good applicability for registration of a subsequent cardiac cycle.     

Role of NF-E2-related factor 2 in neuroprotective effect of l-carnitine against high glucose-induced oxidative stress in the retinal ganglion cells

l-Carnitine (LC) has protective effects on high glucose-induced oxidative stress in the retinal ganglion cells (RGCs). The aim of this study was to investigate the role of NF-E2-related factor 2 (Nrf2), Kelch like-ECH-associated protein 1 (Keap1), haemoxygenase-1 (HO-1) and γ-glutamyl cysteine synthetase (γ-GCS) in the protective effect of LC on RGCs. RGCs were first processed with high concentrations of glucose. LC treatment at three concentrations (50 μM, 100 μM and 200 μM) was applied to high glucose stimulated RGCs. The expression of Nrf2, Keap1, haemoxygenase-1 (HO-1) and γ-glutamyl cysteine synthetase (γ-GCS) was quantified by Western blot in the treatment and control (high glucose stimulation) groups. In the three LC groups (50 μM, 100 μM and 200 μM), Nrf-2 (0.71 ± 0.04, 0.89 ± 0.05, 1.24 ± 0.05 vs 0.56 ± 0.03, p < 0.05), HO-1 (0.58 ± 0.04, 0.76 ± 0.06, 0.89 ± 0.07 vs 0.25 ± 0.03, p < 0.01), and γ-GCS protein expression (0.66 ± 0.03, 0.79 ± 0.05, 0.84 ± 0.08 vs 0.84 ± 0.08, p < 0.01) was higher than in the control group. The levels of Keap1 protein were in the LC groups were lower than in the control group (0.50 ± 0.03, 0.45 ± 0.02, 0.53 ± 0.03 vs 0.86 ± 0.05, p < 0.01). In conclusion, in high glucose stimulated RGCs, LC treatment was associated with an increased level of Nrf2, HO-1and γ-GCS. LC treatment was also associated with a reduced expression of Keap1 protein. These results suggest that the protective effect of LC treatment on RGCs may be related to Nrf2-Keap1 pathway.