Personalized Pre- and Post-Operative Hemodynamic Assessment of Aortic Coarctation from 3D Rotational Angiography.

PURPOSE: Coarctation of Aorta (CoA) is a congenital disease consisting of a narrowing that obstructs the systemic blood flow. This proof-of-concept study aimed to develop a framework for automatically and robustly personalizing aortic hemodynamic computations for the assessment of pre- and post-intervention CoA patients from 3D rotational angiography (3DRA) data. METHODS: We propose a framework that combines hemodynamic modelling and machine learning (ML) based techniques, and rely on 3DRA data for non-invasive pressure computation in CoA patients. The key features of our framework are a parameter estimation method for calibrating inlet and outlet boundary conditions, and regional mechanical wall properties, to ensure that the computational results match the patient-specific measurements, and an improved ML based pressure drop model capable of predicting the instantaneous pressure drop for a wide range of flow conditions and anatomical CoA variations. RESULTS: We evaluated the framework by investigating 6 patient datasets, under pre- and post-operative setting, and, since all calibration procedures converged successfully, the proposed approach is deemed robust. We compared the peak-to-peak and the cycle-averaged pressure drop computed using the reduced-order hemodynamic model with the catheter based measurements, before and after virtual and actual stenting. The mean absolute error for the peak-to-peak pressure drop, which is the most relevant measure for clinical decision making, was 2.98 mmHg for the pre- and 2.11 mmHg for the post-operative setting. Moreover, the proposed method is computationally efficient: the average execution time was of only [Formula: see text] minutes on a standard hardware configuration. CONCLUSION: The use of 3DRA for hemodynamic modelling could allow for a complete hemodynamic assessment, as well as virtual interventions or surgeries and predictive modeling. However, before such an approach can be used routinely, significant advancements are required for automating the workflow.

When and why direct transmission models can be used for environmentally persistent pathogens.

Variants of the susceptible-infected-removed (SIR) model of Kermack & McKendrick (1927) enjoy wide application in epidemiology, offering simple yet powerful inferential and predictive tools in the study of diverse infectious diseases across human, animal and plant populations. Direct transmission models (DTM) are a subset of these that treat the processes of disease transmission as comprising a series of discrete instantaneous events. Infections transmitted indirectly by persistent environmental pathogens, however, are examples where a DTM description might fail and are perhaps better described by models that comprise explicit environmental transmission routes, so-called environmental transmission models (ETM). In this paper we discuss the stochastic susceptible-exposed-infected-removed (SEIR) DTM and susceptible-exposed-infected-removed-pathogen (SEIR-P) ETM and we show that the former is the timescale separation limit of the latter, with ETM host-disease dynamics increasingly resembling those of a DTM when the pathogen's characteristic timescale is shortened, relative to that of the host population. Using graphical posterior predictive checks (GPPC), we investigate the validity of the SEIR model when fitted to simulated SEIR-P host infection and removal times. Such analyses demonstrate how, in many cases, the SEIR model is robust to departure from direct transmission. Finally, we present a case study of white spot disease (WSD) in penaeid shrimp with rates of environmental transmission and pathogen decay (SEIR-P model parameters) estimated using published results of experiments. Using SEIR and SEIR-P simulations of a hypothetical WSD outbreak management scenario, we demonstrate how relative shortening of the pathogen timescale comes about in practice. With atttempts to remove diseased shrimp from the population every 24h, we see SEIR and SEIR-P model outputs closely conincide. However, when removals are 6-hourly, the two models' mean outputs diverge, with distinct predictions of outbreak size and duration.

Pulmonary hypertension in patients with a subaortic right ventricle: prevalence, impact and management.

OBJECTIVE: This study sought to determine the prevalence, predictors, prognostic relevance and evolution of pulmonary hypertension (PH) (mean pulmonary artery pressure ≥25 mm Hg) in adult patients with a subaortic right ventricle (RV) in a biventricular circulation (2V-RV). METHODS: We analysed retrospective data from patients with 2V-RV undergoing cardiac catheterisation in our centre between 2000 and 2018. Echocardiographic assessment of subpulmonary ventricular pressures (left ventricular systolic pressure (LVSP)), age and B-type natriuretic peptide (BNP) were assessed as PH screening tools. Kaplan-Meier curves examined time to a composite outcome of death, transplant or ventricular assist device (VAD). Data from repeat catheterisations were analysed to evaluate PH changes over time, including the effects of therapy. RESULTS: A total of 141 patients (median age 39 (IQR 33-45) years, 68% men) underwent 191 cardiac catheterisations. At baseline, 55% had PH (isolated postcapillary 24%, combined precapillary and postcapillary 26% and precapillary 5%). BNP (area under the curve 0.80; 95% CI 0.72 to 0.88; p<0.0001), but not age at catheterisation or echocardiographic estimates of LVSP were associated with the presence of PH. The absence of PH and BNP <100 pg/mL discriminated a subgroup at very low risk during short-term (2.5 (1.3-3.9) years) follow-up (p<0.0001). Diuretics, milrinone and VAD improved haemodynamics over time. CONCLUSION: PH is prevalent in patients with 2V-RV even when asymptomatic. It is difficult to identify by echocardiography and most importantly, is strongly associated with adverse outcomes. PH affects prognosis and transplant options for this patient group and yet is often amenable to treatment. Awareness of these results ought to lower the threshold for invasive haemodynamic assessment and may change the management of failing patients with 2V-RV.

Comparison of service utilisation and costs of working age adults and older adults receiving treatment for psychosis and severe non-psychotic conditions in England: implications for commissioning.

OBJECTIVE: Current plans in the English National Health Service are to replace block contracts for mental health providers with a single tariff for each 'cluster' of conditions. A single tariff will not take into account the potential additional complexity and costs inherent in caring for older people. To examine the basis for a uniform tariff, differences in service utilisation and costs between working age adults and older adults in two populous clusters (non-psychotic, psychotic) were investigated across five mental health healthcare providers in and around London. METHODS: Retrospective review of records over 3 months assessing service utilisation and costs using the Client Services Receipt Inventory. RESULTS: Records of 362 patients were reviewed, 179 older adults (90 non-psychotic, 89 psychotic) and 183 adults of working age (83 non-psychotic, 100 psychotic). Older adults in both clusters had more tests, assessments and home visits. Overall costs of care of older adults were significantly higher in the non-psychotic cluster (£5634, vs £4405 psychotic, p = 0.044). CONCLUSIONS: An appropriate age-related tariff is required for each cluster. Copyright © 2016 John Wiley & Sons, Ltd.

Three-dimensional rotational angiography in the assessment of vascular and airway compression in children after a cavopulmonary anastomosis.

The aim of the study was to examine the role of three-dimensional rotational angiography (3DRA) in assessing vascular and airway narrowing in children with a bidirectional cavopulmonary anastomosis (BCPA). The course of children with single ventricle physiology is often complicated by left pulmonary artery (LPA) and/or bronchial stenosis and may be related to aortic compression. 3DRA may be useful in evaluating this complex anatomy and possible mechanisms for the observed obstruction. Clinical data and imaging (2D angiography and 3DRA) of children with a BCPA were reviewed retrospectively. Measurements were taken at similar locations along the pulmonary arteries in both modalities and in the airways on 3DRA. Twenty-five children with a previous BCPA were assessed at mean age of 3.1 ± 2.0 years and weight of 13.6 ± 3.6 kg. Excellent correlation was found between 3DRA and 2D angiographic LPA measurements (r = 0.89, p < 0.0001). Twelve children had qualitative LPA stenosis on 3DRA, with a stenotic dimension of 6.6 ± 2.2 mm on 2D angiography and 6.8 ± 1.9 mm on 3DRA (r = 0.94, p < 0.0001). Ten cases with LPA stenosis also had bronchial stenosis (83 %). Qualitative airway assessment correlated with quantitative bronchial dimensions from 3DRA-derived tomographic images: Bronchial stenosis measured 4.4 ± 1.6 versus 5.9 ± 1.1 mm in those with a normal appearing bronchus (p = 0.009). Hybrid patients (initial palliation with bilateral pulmonary artery banding and arterial ductal stenting, n = 5) and all patients with a Damus-Kaye-Stansel (DKS) anastomosis (n = 9) were more likely to have LPA and left bronchial stenosis (OR 7.7, p = 0.04). 3DRA is a useful and accurate tool in assessment of LPA and airway narrowing after BCPA. Hybrid and DKS patients are more prone to LPA and bronchial stenosis, and 3DRA can provide insight into the mechanism.

Thoracoscopic ligation versus coil occlusion for patent ductus arteriosus: a matched cohort study of outcomes and cost.

BACKGROUND: Coil occlusion (CO) and video-assisted thoracoscopic surgery (VATS) have both emerged as minimal access therapies for patent ductus arteriosus (PDA). These techniques have not previously been statistically compared. METHODS: Twenty-four consecutive children undergoing VATS for PDA were each retrospectively matched by PDA diameter and child weight to two children undergoing CO (total 48) during the same time period. The two modalities were compared with respect to outcome and cost. Statistical analysis was performed using a Student's t-test and Mantel-Haenszel relative risk. Cost analysis from an institutional perspective was used to compare resource consumption. RESULTS: Mean PDA diameter was 3.6 +/- 1.2 mm in both groups. Mean age and weight for VATS and CO children were 2.7 and 2.9 yrs and 13.2 and 13.1 kg, respectively. Mean surgical times were 94 +/- 34 min for VATS and 50 +/- 23 min for CO (p < 0.0001). Mean length of stay was 1.6 +/- 0.2 days for VATS and 0.6 +/- 0.2 days for CO (Mantel-Haenszel RR (95% CI) = 0.15 [0.07, 0.29], p < 0.0001). Mean fluoroscopy time with CO was 13 +/- 7 min. No VATS or CO children required conversion to open surgical ligation. Two children in each arm (8% VATS, 4% CO) required indefinite antibiotic endarteritis prophylaxis for a persistent shunt. The cost per child was C$ 4282.80 (Canadian dollars) for VATS and C$ 3958.08 for CO. CONCLUSIONS: VATS is as efficacious for PDA closure as CO but requires longer surgical times and lengths of stay. Costs for each procedure are similar.

Transcatheter device versus surgical closure of ventricular septal defects: a clinical decision analysis.

OBJECTIVES: To compare transcatheter device versus surgical closure of ventricular septal defects (VSDs). METHODS: A clinical decision analysis was performed using standard gamble interviews. RESULTS: Device was initially preferred in 39 respondents (89%) and surgery in 5 (11%). The inherent difference in value between a perfect surgery and a perfect device (disutility of surgery) was equal to a mean risk of death of (1.2 +/- 2.2)%. Final values from decision analysis were initially equivalent. Values adjusted for estimated mortality, however, favored device (mean: 0.979 +/- 0.032) versus surgery (mean: 0.971 +/- 0.032), P = 0.052. When values were further adjusted for disutilities, device was significantly preferred (0.978 +/- 0.032) versus surgery (0.961 +/- 0.044), P < 0.005. Surgery would be preferred if the probability of major complications decreased below 5% or minor complications below 6%. CONCLUSIONS: When outcomes and their values are considered in a systematic manner, transcatheter device closure of suitable VSDs is favored over surgical repair.

Interventional strategies in the management of peripheral pulmonary artery stenosis.

Peripheral pulmonary artery stenosis challenges therapeutic algorithms for the management of congenital heart malformations. Surgical repair of the proximal pulmonary artery lesion remains with a high recurrence rate while the distal lesions are difficult to access. With the development of transcatheter interventional strategies in the early 1980s, a number of transcatheter treatment options became available. In this review, we summarize the current state of the art for interventional strategies in the management of peripheral pulmonary artery stenosis.