A truncating variant altering the extreme C-terminal region of desmoplakin (DSP) suggests the crucial functional role of the region: a case report study

BACKGROUND

Homozygous truncating mutations located in the C-terminal region of the desmoplakin gene (DSP) are known to mainly cause Carvajal syndrome, an autosomal recessive syndromic form of arrhythmogenic cardiomyopathy with an extra-cardiac cutaneous phenotype.

CASE PRESENTATION

Here we describe a female proband with a documented arrhythmogenic left ventricular cardiomyopathy and a syncopal episode at the age of 13, who was found homozygous for the novel DSP variant: NM_004415.4:c.8586delC, p.(Ser2863Hisfs*20) at the extreme C-terminal region of the protein, just 8 amino acids upstream the stop codon. She did not have any of the typical dermatological symptoms that characterize Carvajal syndrome. Her brother had died suddenly at the age of 18 during exercise and was found homozygous for the same variant at the post-mortem, while their parents were heterozygous. The region of origin of both parents was the same geographic area of Greece, but they were not aware of any common ancestor. Detailed clinical examination revealed that the mother displayed a mild arrhythmic phenotype, while the father was asymptomatic.

CONCLUSION

These observations pinpoint to a significant functional role of the extreme C-terminal tail of the protein.

Complex adult congenital heart disease on cross-sectional imaging: an introductory overview

Congenital heart disease is the most common group of congenital pathology. Over the past few decades, advances in surgical treatment have resulted in a rising population of adult patients with repaired complex congenital heart disease. Although the quality of life has greatly improved, a significant proportion of morbidities encountered in clinical practice is now seen in adults rather than in children. These patients often have significant haemodynamic pathophysiology necessitating repeat intervention. CT and MRI are excellent imaging modalities, which help elucidate potential complications that may need urgent management. Although imaging should be performed in specialised centres, occasionally patients may present acutely to emergency departments in hospitals with little experience in managing potentially complex patients. The purpose of this article is to provide an introductory overview to the radiologist who may not be familiar with complex congenital heart disease in adult patients. This educational review has three main sections: (1) a brief overview of the post-operative anatomy and surgical management of the most common complex conditions followed by (2) a discussion on CT/MRI protocols and (3) a review of the various complications and their CT/MRI findings.

Production and characterisation of adsorbents synthesised by hydrothermal carbonisation of biomass wastes

Surface structure and chemical properties of adsorbents are important factors required to understand the mechanism of adsorption. The purpose of this study was to produce hydrochars from biomass using hydrothermal carbonisation (HTC) and to analyse their sorption capacities. The biomass used in this study were coco-peat (CP), coconut shell (CS), eggshell (ES), rice husk (RH) and lemon peel (LP). The operating conditions for HTC were 200 °C and 20 h residence time. The characterisation methods consisted of Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), Fourier Transform Infrared Ray (FTIR) Spectroscopy, and Brunauer, Emmett and Teller (BET). The results showed that HTC improved the sorption capacities of the biomass wastes. It was found that hydrochars were crispy and flaky with more micro- and meso-porous structures, indicating that lignin and other components were denatured due to carbonisation. This led to the creation of more active sites for sorption and pollutant binding. The hydrochars showed a percentage increase in carbon content and a decrease in oxygen content with traces of other elements, compared to their corresponding raw biomass. The major functional groups identified were –OH and –COOH. The surface area of the hydrochars which include CP (2.14 m2/g), CS (14.04 m2/g), ES (0.50 m2/g), RH (15.74 m2/g), and LP (6.89 m2/g) were significantly improved compared with those of the raw biomass. The study showed that the hydrochars produced from the biomass wastes have the potential to be used as adsorbents.

Simultaneous left atrium anatomy and scar segmentations via deep learning in multiview information with attention

Three-dimensional late gadolinium enhanced (LGE) cardiac MR (CMR) of left atrial scar in patients with atrial fibrillation (AF) has recently emerged as a promising technique to stratify patients, to guide ablation therapy and to predict treatment success. This requires a segmentation of the high intensity scar tissue and also a segmentation of the left atrium (LA) anatomy, the latter usually being derived from a separate bright-blood acquisition. Performing both segmentations automatically from a single 3D LGE CMR acquisition would eliminate the need for an additional acquisition and avoid subsequent registration issues. In this paper, we propose a joint segmentation method based on multiview two-task (MVTT) recursive attention model working directly on 3D LGE CMR images to segment the LA (and proximal pulmonary veins) and to delineate the scar on the same dataset. Using our MVTT recursive attention model, both the LA anatomy and scar can be segmented accurately (mean Dice score of 93% for the LA anatomy and 87% for the scar segmentations) and efficiently ( ∼ 0.27 s to simultaneously segment the LA anatomy and scars directly from the 3D LGE CMR dataset with 60-68 2D slices). Compared to conventional unsupervised learning and other state-of-the-art deep learning based methods, the proposed MVTT model achieved excellent results, leading to an automatic generation of a patient-specific anatomical model combined with scar segmentation for patients in AF.

Myocardial fibrosis and the effect of primary prophylactic defibrillator implantation in patients with non-ischemic systolic heart failure-DANISH-MRI

AIMS

Patients with non-ischemic systolic heart failure have an increased risk of sudden cardiac death (SCD). Myocardial fibrosis, detected as late gadolinium enhancement (LGE) with cardiac magnetic resonance (CMR), has been shown to predict all-cause mortality. We hypothesized that LGE can identify patients with non-ischemic heart failure who will benefit from ICD implantation.

METHODS AND RESULTS

In this prospective observational sub-study of the Danish Study to Assess the Efficacy of ICDs in Patients with Nonischemic Systolic Heart Failure on Mortality (DANISH), 252 patients underwent CMR. LGE was quantified by the full width/half maximum method. The primary endpoint was all-cause mortality. LGE could be adequately assessed in 236 patients, median age was 61 years and median duration of heart failure was 14 months; there were 108 patients (46%) randomized to ICD. Median follow-up time was 5.3 years. Median left ventricular ejection fraction on CMR was 35%. In all, 50 patients died. LGE was present in 113 patients (48%). The presence of LGE was an independent predictor of all-cause mortality (HR 1.82; 95% CI 1.002-3.29; P = .049) after adjusting for known cardiovascular risk factors. ICD implantation did not impact all-cause mortality, for either patients with LGE (HR 1.18; 95% CI 0.59-2.38; P = .63), or for patients without LGE (HR 1.00; 95% CI 0.39-2.53; P = .99), (P for interaction =0.79).

CONCLUSION

In patients with non-ischemic systolic heart failure, LGE predicted all-cause mortality. However, in this cohort, LGE did not identify a group of patients who survived longer by receiving an ICD.

P1491 Aneurysm of the membranous septum after spontaneous closure of ventricular septal defect combined with bicuspid aortic valve

An 18-year-old asymptomatic patient with a cardiac background of ventricular septal defect (VSD) and bicuspid aortic valve diagnosed in early childhood, was referred to our Adult Congenital Heart Disease (ACHD) outpatient clinic for routine assessment. Imaging by transthoracic echocardiography and Cardiac Magnetic Resonance (CMR) showed a well-developed multilobulated appendiform saccular formation (34x20mm) arising from the right ventricular side of the membranous septum inferior to the anterior aortic cusp and just beneath the septal leaflet of the tricuspid valve, protruding into the right ventricular outflow tract and the body of right ventricle. The fibrous quality and the absence of myocardium in this structure led to the formation of an aneurysm of the membranous septum (AMS) with the characteristic outpouching or ‘windsock’ appearance from its distention during ventricular systole (Figure). There was no shunt between the ventricles. The aortic valve was true bicuspid with severe aortic regurgitation and an eccentric jet towards the anterior leaflet of the mitral valve. The left ventricle was dilated with preserved systolic function. On the basis of the above information the Heart Team decided for surgical management.Both the presence of a true bicuspid valve (embryologically linked to VSD) as well as the pre-existing left-to-right shunting (until the spontaneous VSD closure) seem to have contributed to aortic valve dysfunction in this case. An interesting physical phenomenon concerning fluid dynamics, known as the ‘Venturi effect’, occurs in patients with ‘aneurysmal transformation’ of the ventricular septum, where the VSD becomes smaller creating thus a low-pressure zone that affects the adjacent aortic valve cusp, causing prolapse and, hence, aortic valve regurgitation.

Non-invasive imaging evaluation of patients with AMS is required for optimal diagnosis and treatment as well as for follow-up examinations. Echocardiography is an effective tool for diagnosing AMS, mainly as an incidental finding in asymptomatic subjects whereas CMR is capable of three-dimensional anatomical assessment and provides functional data about the blood flow into the aneurysm and integrity of the ventricular membranous septum.

Abstract P1491 Figure

P259 Incidental giant Coronary artery aneurysm in the right coronary artery

Giant coronary artery aneurysm (CAAs) are unusual with reported incidence rate of 0.02% of patients who undergo cardiac surgery; often the proximal right coronary artery (RCA) is involved. They are defined as a localized area of dilatation exceeding 2cm in diameter. We report a case of an incidentally diagnosed partially thrombosed right CAA.

A 69 years-old-male, with history of possible Marfan´s Syndrome and previously negative genetic study, was referred to the Cardiovascular Magnetic Resonance Unit for an outpatient assessment of his aortic dimensions. He had history of cardiac surgery with valve-sparing aortic root replacement, 15 years ago. Additionally, he had strong family history of sudden death probably related to acute aortic syndromes. The patient was asymptomatic, but interestingly during his most recent outpatient clinic appointment he reported an episode of chest pain 5 months before for which he called an ambulance but as the ECG only showed bradycardia, he was not taken to the hospital. Physical examination and routine blood test were irrelevant. The CMR study of the thoracic aorta showed an incidental aneurysmal dilatation of the proximal/mid RCA (diameter:40mm and length:60mm, Figure1:A). It was partially filled with a parietal thrombus. Biventricular ejection fraction was normal. CT angiogram confirmed the CMR findings (Figure1:B-C) and also showed ectatic LAD and distal RCA arteries. Myocardial stress perfusion scintigraphy exposed partial thickness infarction of the inferior and inferoseptal walls with a scar burden of 15% with additional mild superimposed ischaemia accounting to less than 5% of the myocardium. Coronary angiogram was then performed and due the complexity of the lesion and the high risk of embolization of thrombotic material in a patient with normal ejection fraction, the overall consensus was to treat him medically with anticoagulation, beta-blockers, ARE inhibitors and statins.

CAAs are rare, occurring in 0.3% to 4.9% of patients undergoing coronary angiograms, while giant coronary artery aneurysms are even rarer. They are most commonly associated with male gender and hyperlipidemias. Atherosclerosis remains the most common cause of CAAs although they are also associated with congenital malformations, Kawasaki disease, autoimmune diseases (polyarteritis nodosa, lupus erythematosus and scleroderma), trauma, coronary artery dissection, rheumatic heart disease, mycotic coronary emboli, and syphilis, among others. In our case, comprehensive multimodality imaging led to the definitive diagnosis. Untreated CAAs may be complicated by ischaemia, myocardial infarction, distal embolization due to thrombus formation within the aneurysm, calcification, fistula formation and spontaneous rupture. Various surgical approaches to treat giant CAAs are reported in the literature, such us, excision of the aneurysm with bypass to the distal coronary artery. However, percutaneous intervention could be possible in some cases.

Abstract P259 Figure 1.

Biological groundwater treatment for hexavalent chromium removal at low chromium concentrations under anoxic conditions

The objective of this work is to evaluate biological groundwater treatment systems that will achieve hexavalent chromium removal from groundwater at hexavalent chromium (Cr(VI)) groundwater concentrations in the 0-200 μg/L range under anoxic conditions. The effect of type of organic substrate added as feed to the groundwater treatment system (milk, sugar and cheese whey), the effect of different concentrations of chemical oxygen demand added in the feed (100, 150 and 200 mg/L) and the effect of different hydraulic residence time (1.7, 0.9 and 0.7 d) on process performance were evaluated through the operation of a series of sequential batch reactors under anoxic conditions. Biomass receiving Cr(VI) contaminated groundwater with a low nitrates content exhibited similar Cr(VI) removal efficiency under reductive conditions, with biomass receiving Cr(VI) contaminated groundwater with a high nitrates content. The concentration of organic substrate was crucial for the microbial reduction of Cr(VI). The different hydraulic residence time of the reactors and the different types of organic substrates added did not affect the efficiency of hexavalent chromium removal which was complete. This study demonstrates that biological systems operating under reductive conditions can efficiently treat groundwater containing low or high nitrates concentration and can provide complete hexavalent chromium removal at initial Cr(VI) concentrations of 200 μg/L.

Fully automatic segmentation and objective assessment of atrial scars for long-standing persistent atrial fibrillation patients using late gadolinium-enhanced MRI

PURPOSE

Atrial fibrillation (AF) is the most common heart rhythm disorder and causes considerable morbidity and mortality, resulting in a large public health burden that is increasing as the population ages. It is associated with atrial fibrosis, the amount and distribution of which can be used to stratify patients and to guide subsequent electrophysiology ablation treatment. Atrial fibrosis may be assessed noninvasively using late gadolinium-enhanced (LGE) magnetic resonance imaging (MRI) where scar tissue is visualized as a region of signal enhancement. However, manual segmentation of the heart chambers and of the atrial scar tissue is time consuming and subject to interoperator variability, particularly as image quality in AF is often poor. In this study, we propose a novel fully automatic pipeline to achieve accurate and objective segmentation of the heart (from MRI Roadmap data) and of scar tissue within the heart (from LGE MRI data) acquired in patients with AF.

METHODS

Our fully automatic pipeline uniquely combines: (a) a multiatlas-based whole heart segmentation (MA-WHS) to determine the cardiac anatomy from an MRI Roadmap acquisition which is then mapped to LGE MRI, and (b) a super-pixel and supervised learning based approach to delineate the distribution and extent of atrial scarring in LGE MRI. We compared the accuracy of the automatic analysis to manual ground truth segmentations in 37 patients with persistent long-standing AF.

RESULTS

Both our MA-WHS and atrial scarring segmentations showed accurate delineations of cardiac anatomy (mean Dice = 89%) and atrial scarring (mean Dice = 79%), respectively, compared to the established ground truth from manual segmentation. In addition, compared to the ground truth, we obtained 88% segmentation accuracy, with 90% sensitivity and 79% specificity. Receiver operating characteristic analysis achieved an average area under the curve of 0.91.

CONCLUSION

Compared with previously studied methods with manual interventions, our innovative pipeline demonstrated comparable results, but was computed fully automatically. The proposed segmentation methods allow LGE MRI to be used as an objective assessment tool for localization, visualization, and quantitation of atrial scarring and to guide ablation treatment.

Challenging Occam's Razor: An Unusual Combination of Sarcoidosis and Amyloidosis. The Value of Cardiac Magnetic Resonance Imaging in Infiltrative Cardiomyopathies

We describe the case of a 66-year old woman with the extremely rare combination of sarcoidosis and amyloidosis (light chain) and the important role of cardiovascular magnetic resonance imaging to differentiate between these 2 infiltrative diseases. Myocardial characterization with T1 mapping can improve disease detection, especially in overlap cases, and possibly obviate the need for cardiac biopsy.

Rapid automatic segmentation of abnormal tissue in late gadolinium enhancement cardiovascular magnetic resonance images for improved management of long-standing persistent atrial fibrillation

Background

Atrial fibrillation (AF) is the most common heart rhythm disorder. In order for late Gd enhancement cardiovascular magnetic resonance (LGE CMR) to ameliorate the AF management, the ready availability of the accurate enhancement segmentation is required. However, the computer-aided segmentation of enhancement in LGE CMR of AF is still an open question. Additionally, the number of centres that have reported successful application of LGE CMR to guide clinical AF strategies remains low, while the debate on LGE CMR’s diagnostic ability for AF still holds. The aim of this study is to propose a method that reliably distinguishes enhanced (abnormal) from non-enhanced (healthy) tissue within the left atrial wall of (pre-ablation and 3 months post-ablation) LGE CMR data-sets from long-standing persistent AF patients studied at our centre.

Methods

Enhancement segmentation was achieved by employing thresholds benchmarked against the statistics of the whole left atrial blood-pool (LABP). The test-set cross-validation mechanism was applied to determine the input feature representation and algorithm that best predict enhancement threshold levels.

Results

Global normalized intensity threshold levels T_PRE = 1 1/4 and T_POST = 1 5/8 were found to segment enhancement in data-sets acquired pre-ablation and at 3 months post-ablation, respectively. The segmentation results were corroborated by using visual inspection of LGE CMR brightness levels and one endocardial bipolar voltage map. The measured extent of pre-ablation fibrosis fell within the normal range for the specific arrhythmia phenotype. 3D volume renderings of segmented post-ablation enhancement emulated the expected ablation lesion patterns. By comparing our technique with other related approaches that proposed different threshold levels (although they also relied on reference regions from within the LABP) for segmenting enhancement in LGE CMR data-sets of AF patients, we illustrated that the cut-off levels employed by other centres may not be usable for clinical studies performed in our centre.

Conclusions

The proposed technique has great potential for successful employment in the AF management within our centre. It provides a highly desirable validation of the LGE CMR technique for AF studies. Inter-centre differences in the CMR acquisition protocol and image analysis strategy inevitably impede the selection of a universally optimal algorithm for segmentation of enhancement in AF studies.

Relation of Proximal Aorta Stiffness to Left Ventricular Diastolic Function in Patients with End-Stage Renal Disease

AIM

We examined the relationship between proximal aortic stiffness and left ventricular (LV) diastolic function in patients with end-stage renal disease (ESRD).

PATIENTS AND METHODS

We studied 99 patients with ESRD with preserved LV ejection fraction greater than 50% and 83 controls. We assessed the aorta stiffness by measuring the pulse wave velocity (PWV) in the proximal aorta (PWVr) using a novel echo application and in the descending aorta (PWVcf) using a foot-to-foot method. Patients were classified according to LV diastolic filling pattern into normal, delayed relaxation, pseudonormal, and restrictive filing pattern groups.

RESULTS

Patients with ESRD had increased PWVr, PWVcf, and LV mass index (LVMI) compared with controls (all P < .0001). Patients with advanced diastolic dysfunction showed increased PWVr (P < .001) and PWVcf (P = .007) compared with those with mild diastolic dysfunction. PWVr was correlated to PWVcf (r = 0.74, P < .001) in patients with ESRD. Multivariate linear regression analysis revealed that PWVr was independently correlated to both LVMI and LV diastolic filling pattern.

CONCLUSIONS

Increased LVMI, advanced LV diastolic dysfunction, and generalized aortic stiffening were observed in patients with ESRD. Proximal aorta stiffness is associated with both increased LVMI and advanced LV diastolic dysfunction in those patients.