scholarly journals Cross-Entropy Learning for Aortic Pathology Classification of Artificial Multi-Sensor Impedance Cardiography Signals

Entropy ◽  
2021 ◽  
Vol 23 (12) ◽  
pp. 1661
Author(s):  
Tobias Spindelböck ◽  
Sascha Ranftl ◽  
Wolfgang von der Linden
Keyword(s):  
Blood Flow ◽  
Aortic Dissection ◽  
Network Architecture ◽  
Impedance Cardiography ◽  
False Lumen ◽  
Flow Characteristics ◽  
Virtual Patient ◽  
Cross Entropy ◽  
Aortic Pathology ◽  
Aortic Dissections

An aortic dissection, a particular aortic pathology, occurs when blood pushes through a tear between the layers of the aorta and forms a so-called false lumen. Aortic dissection has a low incidence compared to other diseases, but a relatively high mortality that increases with disease progression. An early identification and treatment increases patients’ chances of survival. State-of-the-art medical imaging techniques have several disadvantages; therefore, we propose the detection of aortic dissections through their signatures in impedance cardiography signals. These signatures arise due to pathological blood flow characteristics and a blood conductivity that strongly depends on the flow field, i.e., the proposed method is, in principle, applicable to any aortic pathology that changes the blood flow characteristics. For the signal classification, we trained a convolutional neural network (CNN) with artificial impedance cardiography data based on a simulation model for a healthy virtual patient and a virtual patient with an aortic dissection. The network architecture was tailored to a multi-sensor, multi-channel time-series classification with a categorical cross-entropy loss function as the training objective. The trained network typically yielded a specificity of (93.9±0.1)% and a sensitivity of (97.5±0.1)%. A study of the accuracy as a function of the size of an aortic dissection yielded better results for a small false lumen with larger noise, which emphasizes the question of the feasibility of detecting aortic dissections in an early state.

scholarly journals Treatment of Acute Stanford Type B Aortic Dissection With a Novel Cylindrical Balloon Catheter in Dogs

Circulation ◽  
2000 ◽  
Vol 102 (suppl_3) ◽  
Author(s):  
Hiromu Terai ◽  
Nobushige Tamura ◽  
Tatsuo Nakamura ◽  
Kazunobu Nishimura ◽  
Norimasa Tsutsui ◽  
...  
Keyword(s):  
Blood Flow ◽  
Aortic Dissection ◽  
Balloon Catheter ◽  
False Lumen ◽  
Aortic Blood Flow ◽  
Acute Type ◽  
Type B ◽  
Type B Aortic Dissection ◽  
True Lumen ◽  
Descending Aorta

Background —Despite recent progress in medical and surgical treatment, acute type B aortic dissection still carries a high mortality rate. We have developed a novel cylindrical balloon catheter for less invasive treatment to block the entry of the dissection and induce thrombotic occlusion of the false lumen. The balloon has the shape of a sheet when deflated but a double-cylinder shape when inflated. Therefore, aortic blood flow is maintained through the cylindrical lumen during balloon inflation. Methods and Results —Six beagle dogs underwent a left thoracotomy at the 6th intercostal space. An acute dissection of 4-cm length was created surgically on the descending aorta. The balloon catheter was inserted through the distal descending aorta and advanced to the entry site. The balloon catheter was inflated for 6 hours. The blood flow in the descending aorta and the position of the balloon was monitored by color Doppler echovasculography. Four dogs were killed humanely on the following day and 2 dogs 10 days after the surgery. The descending aorta was examined macroscopically and microscopically in all dogs. In all dogs, the false lumen was occluded by thrombi. Although no dog had clinical evidence of distal thromboembolism, 2 of the 4 dogs that were killed on the second postoperative day had fresh mural thrombi in the true lumen. Conclusions —The false lumen of the acute type B aortic dissection was effectively occluded by the novel cylindrical balloon catheter in the canine experimental model. The thrombus formation in the true lumen is the problem to be solved.

Quantitative Comparison of 7D MRI Flow Measurements With CFD Results in a Type B Aortic Dissection

2012 ◽  
Author(s):  
Christof Karmonik ◽  
Rachel E. Clough ◽  
Alan B. Lumsden ◽  
Peter Taylor ◽  
Jean Bismuth
Keyword(s):  
Velocity Field ◽  
Aortic Dissection ◽  
Diastolic Pressure ◽  
False Lumen ◽  
The United States ◽  
Image Correlation ◽  
Acute Type ◽  
Flow Measurements ◽  
Risk Of Death ◽  
Aortic Dissections

Aortic dissections, which split the aorta into a true lumen (TL) and a false lumen (FL), represent a serious medical condition, affecting otherwise healthy young people with an incidence between 5,000–10,000 cases per year in the United States and 3000 in Europe [1]. A recent study of the outcome of acute type III/ Stanford B aortic dissections (dissections confined to the descending aorta, B-AD) revealed that the long-term prognosis after hospital discharge of patients with B-AD is heterogeneous, with reported survival rates ranging from 56 to 92% at 1 year and from 48 to 82% at 5 years [2]. A partially thrombosed FL, results in a 2.7-fold increase in risk of death [3]. In a recent ex-vitro study, Tasi et al. investigated a chronic aortic dissection in three models [4]. The largest FL diastolic pressure was observed for the model simulating patients with partial false lumen thrombosis and occlusion of the distal entry tear. This study demonstrated that pressure differences between TL and FL are dependent on the geometry of the particular aortic dissection and the location and size of entry tears. A computational fluid dynamics (CFD) study on the effects of entry and exit tear coverage in B-AD based on a patient-derived geometry reported similar results [5]: In particular, occlusion of the exit tear caused increase FL pressure. Simulating thoracic endovascular repair (TEVAR) by occluding the entrance tear depressurized the FL. The capability of CFD to virtually simulate surgical interventions makes it an appealing method for use in pre-surgical planning. For general acceptance however, validation of the simulated results is needed. Catheter measurements of the pressures in the TL and FL are feasible but not very practicable as insertion of a catheter in the FL through the entry or exit tear bears unjustifiable risk to the patient. More recently, 7D phase contrast magnetic resonance imaging (pcMRI) methods (3 spatial directions, 3 velocity directions and time equal 7 dimensions) have been introduced that allow the acquisition of the 3D velocity field at several time points in the cardiac cycle, thereby providing information that can be directly compared with the velocity field simulated with CFD. Due to the large duration of the image acquisition, compromises in temporal and spatial resolution are made which need to be considered when performing such a comparison. Here we present a method based on interpolating the simulated velocity field onto a structured grid employing direct interpolation and spatial Fourier Fast Transformation (FFT) to replicate artifacts as they are present in the 7D pcMRI data. The interpolated velocity components are the then qualitatively compared using image correlation analysis.

scholarly journals Aortic dissection in Siriraj patients: Computed tomography findings

2017 ◽  
Vol 19 (3) ◽  
pp. 5-25
Author(s):  
Krisdee Prabhasavat ◽  
Sukrit Sorotpinya ◽  
Jitladda Wasinrat ◽  
Somchai Chairoongruang
Keyword(s):  
Aortic Dissection ◽  
Acute Aortic Dissection ◽  
False Lumen ◽  
Type A ◽  
Outer Wall ◽  
Type B ◽  
Computed Tomographic ◽  
Wall Calcification ◽  
Acute Dissection ◽  
Aortic Dissections

Background: CTA has replaced angiography in both diagnosis and evaluation of aortic dissection. Most findings are associated with true and false lumens which account for the most important information in both diagnosis and management. Objective: To describe computed tomographic (CT) findings including types based on Stanford classification, true and false lumens, acute and chronic aortic dissections, relation to origins of aortic branches, complications and other related findings. Methods: Computed tomographic angiography (CTA) scans of one hundred and twenty patients with aortic dissection during 2007 to 2016 were retrospectively reviewed. The findings indicating types, true and false lumens, acute and chronic, origination of aortic branches, complication and other related findings are categorized. Result: Most true lumens were smaller, having outer wall calcification. Most false lumens were larger, showing beak sign, cobweb sign, and intraluminal thrombi. However, the larger lumens could be true lumens as well as the smaller lumen could be a false lumen and outer wall calcification could be seen in a false lumen. The larger true lumens and the smaller false lumens with outer wall calcifications were more often found in chronic aortic dissection than acute aortic dissection. Both acute and chronic aortic dissections were more Stanford type B than type A. Complications included rupture, hemopericardium, hemothorax, hemomediastinum and distal organ infarction, which were more frequent in acute dissection. Intrathoracic complications were more commonly caused by type A acute dissection. Renal infarction was the most common complication in type B acute aortic dissection. Conclusion: Most CT fi ndings of aortic dissection in this study were typical. Atypical fi ndings were also found in both acute and chronic aortic dissections. Outer wall calcifi cations of false lumens in acute aortic dissection were found in 2 cases.

Obtaining True Lumen Access in Aortic Dissections with Iliac Extension

2018 ◽  
Author(s):  
Roshni A. Parikh ◽  
David M. Williams
Keyword(s):  
Blood Flow ◽  
Aortic Dissection ◽  
Lower Extremity ◽  
Endovascular Treatment ◽  
True Lumen ◽  
Femoral Arteries ◽  
Lower Extremity Ischemia ◽  
The Common ◽  
Aortic Dissections ◽  
Extremity Ischemia

Aortic dissection resulting in lower extremity ischemia is an emergent condition requiring urgent endovascular treatment of the aorta and iliofemoral arteries to restore blood flow to the lower extremities. This chapter describes the management, applications, challenges, and potential complications when obtaining bilateral true lumen access during the urgent endovascular treatment of lower extremity ischemia after an aortic dissection. Most interventions require retrograde access to the true lumen; however, if one of the common femoral arteries is dissected, then retrograde access can be a challenge. Utilizing the contralateral true lumen, retrograde access can be confidently obtained through the true lumen of a dissected artery. This chapter illustrates the steps involved in successfully obtaining bilateral retrograde access to the common femoral arteries when these challenging cases arise.

Additional frozen elephant trunk as a bailout for a misdeployed frozen elephant trunk in the false lumen in a patient with acute aortic dissection

2019 ◽  
Author(s):  
Koichi Tamai ◽  
Daijiro Hori ◽  
Koichi Yuri ◽  
Atsushi Yamaguchi
Keyword(s):  
Computed Tomography ◽  
Blood Flow ◽  
Aortic Dissection ◽  
Acute Aortic Dissection ◽  
False Lumen ◽  
Transoesophageal Echocardiography ◽  
Frozen Elephant Trunk ◽  
True Lumen ◽  
Elephant Trunk ◽  
Descending Aorta

Abstract Using a frozen elephant trunk (FET) in patients with acute aortic dissection is an effective method to induce aortic remodelling after surgery. A 40-year-old man with Stanford type A acute aortic dissection underwent emergency total arch replacement with FET. The FET was inserted into the descending aorta under direct vision. However, transoesophageal echocardiography after the deployment of the FET revealed that it was misdeployed in the false lumen. An additional FET was deployed in the true lumen to redirect the blood flow to the true lumen. The patient was discharged from the hospital without any major complications. Computed tomography 6 months after surgery revealed enhanced aortic remodelling without any signs of stent graft-induced new entry. Additional deployment of a FET into the true lumen could be an option for a misdeployed FET in the false lumen.

scholarly journals Repeated Peripheral Embolisms associated with Chronic Aortic Dissection

2019 ◽  
Vol 29 (03) ◽  
pp. 210-214
Author(s):  
Shigeaki Aoyagi ◽  
Mau Amako ◽  
Kumiko Wada ◽  
Tomokazu Kosuga ◽  
Hiroshi Yasunaga
Keyword(s):  
Blood Flow ◽  
Aortic Dissection ◽  
Femoral Artery ◽  
Bypass Graft ◽  
False Lumen ◽  
External Iliac Artery ◽  
Renal Infarction ◽  
Acute Type ◽  
Type B ◽  
The Right

AbstractA male patient developed acute type B aortic dissection (AD) extending to the right external iliac artery (EIA) and left common femoral artery at the age of 56 years. Two months after the diagnosis of AD, he developed right renal infarction suggesting embolism, as the right renal artery arose from a false lumen containing a mural thrombus. Seven years later, at the age of 63 years, the patient was readmitted for acute onset of intermittent claudication in the right leg. On admission, arterial pulses distal to the right femoral artery were absent. The right ankle-brachial pressure index (ABI) was 0.66, while the left ABI was 1.06. Computed tomography (CT) confirmed chronic type B AD and revealed a localized occlusion of the right EIA and disappearance of a small protruding thrombus in the false lumen that was found on the previous CT, suggesting a second embolism. Since recovery of antegrade blood flow was insufficient after catheter embolectomy, femorofemoral bypass was performed with resolution of ischemic symptoms. Postoperatively, the ABI recovered to 0.99 in the right and 1.12 in the left, and CT showed a patent bypass graft and restoration of blood flow to the right leg. This case indicates that embolism should be recognized as one of the possible causes of acute organ ischemia in patients with AD, even in patients with chronic AD.

Transesophageal Echocardiographic Guidance of Thoracic Aortic Stent-Graft Implantation

2002 ◽  
Vol 9 (2_suppl) ◽  
pp. II-14-II-19 ◽  
Author(s):  
Wolfram Schütz ◽  
Albrecht Gauss ◽  
Rainer Meierhenrich ◽  
Reinhard Pamler ◽  
Johannes Görich
Keyword(s):  
Blood Flow ◽  
Aortic Dissection ◽  
Thoracic Aorta ◽  
Stent Graft ◽  
Aortic Coarctation ◽  
False Lumen ◽  
Early Complications ◽  
Stent Grafts ◽  
True Lumen ◽  
Correct Placement

Purpose: To evaluate the efficacy of intraoperative transesophageal echocardiography (TEE) as an adjunctive measure in guiding the implantation of endoluminal stent-grafts in the thoracic aorta. Methods: TEE was used in 21 of 30 patients (27 men; median age 70 years; range 19–77) undergoing implantation of Excluder or Talent stent-grafts for management of 11 type B aortic dissections, 7 thoracic aortic aneurysms, 2 traumatic thoracic aortic ruptures, and an aortic coarctation. We evaluated the ability of TEE to provide evidence of (1) correct placement of the guidewire within the true lumen, (2) reduction in blood flow in the false lumen following stent deployment, and (3) early complications. Results: Definite identification of the true lumen and a reliable evaluation of the position of the stent-graft guidewire during advancement were possible in all patients. Reduction of blood flow within the false lumen following deployment of the stent-graft was visualized in >70% of patients with aortic dissection. In the patient with aortic coarctation, TEE recognized the acute onset of aortic dissection following stent dilation, which resulted in immediate management with an additional stent. Conclusions: The intraoperative use of TEE in the implantation of stent-grafts in the thoracic aorta is not significantly invasive and is easily employed. It permits excellent evaluation of the correct placement of the stent guidewire and, in patients with aortic dissection, intraoperatively visualizes effective blood flow reduction in the false lumen following stent-graft deployment. Its ability to recognize early complications may indicate the need for additional maneuvers during the surgical procedure.

Laser Fenestration for Treatment of a Complicated Chronic Type B Aortic Dissection

2018 ◽  
Vol 52 (3) ◽  
pp. 212-217 ◽  
Author(s):  
Tara Talaie ◽  
Christopher Werter ◽  
Charles Drucker ◽  
Brittany O. Aicher ◽  
Robert Crawford ◽  
...  
Keyword(s):  
Aortic Dissection ◽  
Open Repair ◽  
False Lumen ◽  
Thoracic Endovascular Aortic Repair ◽  
Challenging Problem ◽  
Type B ◽  
Type B Aortic Dissection ◽  
Endovascular Techniques ◽  
Chronic Type ◽  
Aortic Dissections

We report a case of a complex chronic type B aortic dissection treated by thoracic endovascular aortic repair and laser fenestration of the false septum to preserve flow to branch vessels originating from both the true and false lumen. Dissections complicated by thoracoabdominal aneurysmal degeneration with critical organs being perfused by branches arising from both true and false lumens are rare and leave limited options for repair. Despite advancements in endovascular techniques, fenestration remains one of the only means of preserving flow to both the true and false lumens and thus was necessary in the management of our patient. This novel procedure allows complex aortic dissections to be addressed endovascularly, which increases the flexibility and management of this challenging problem that previously required an open repair with significant morbidity.

scholarly journals Multilayer flow modulator enhances vital organ perfusion in patients with type B aortic dissection

2018 ◽  
Vol 315 (5) ◽  
pp. H1182-H1193 ◽  
Author(s):  
Farhad Rikhtegar Nezami ◽  
Lambros S. Athanasiou ◽  
Junedh M. Amrute ◽  
Elazer R. Edelman
Keyword(s):  
Blood Flow ◽  
Shear Stress ◽  
Aortic Dissection ◽  
False Lumen ◽  
Organ Perfusion ◽  
Type B ◽  
Local Flow ◽  
Dynamic Framework ◽  
Computed Tomography Images ◽  
Flow Disturbances

Management of aortic dissections (AD) is still challenging, with no universally approved guideline among possible surgical, endovascular, or medical therapies. Approximately 25% of patients with AD suffer postintervention malperfusion syndrome or hemodynamic instability, with the risk of sudden death if left untreated. Part of the issue is that vascular implants may themselves induce flow disturbances that critically impact vital organs. A multilayer mesh construct might obviate the induced flow disturbances, and it is this concept we investigated. We used preintervention and post-multilayer flow modulator implantation (PM) geometries from clinical cases of type B AD. In-house semiautomatic segmentation routines were applied to computed tomography images to reconstruct the lumen. The device was numerically reconstructed and adapted to the PM geometry concentrically fit to the true lumen centerline. We also numerically designed a pseudohealthy case, where the geometry of the aorta was extracted interpolating geometric features of preintervention, postimplantation, and published representative healthy volunteers. Computational fluid dynamics methods were used to study the time-dependent flow patterns, shear stress metrics, and perfusion to vital organs. A three-element Windkessel lumped parameter module was coupled to a finite-volume solver to assign dynamic outlet boundary conditions. Multilayer flow modulator not only significantly reduced false lumen blood flow, eliminated local flow disturbances, and globally regulated wall shear stress distribution but also maintained physiological perfusion to peripheral vital organs. We propose further investigation to focus the management of AD on both modulation of blood flow and restoration of physiologic end-organ perfusion rather than mere restoration of vascular lamina morphology. NEW & NOTEWORTHY The majority of aortic dissection modeling efforts have focused on the maintenance of physiological flow using minimally invasive placed grafts. The multilayer flow modulator is a complex mesh construct of wires, designed to eliminate flow disruptions in the lumen, regulate the physiological wall stresses, and enhance endothelial function and offering the promise of improved perfusion of vital organs. This has never been fully proved or modeled, and these issues we confirmed using a dynamic framework of time-varying arterial waveforms.

scholarly journals Electrode positioning to investigate the changes of the thoracic bioimpedance caused by aortic dissection – a simulation study

2020 ◽  
Vol 11 (1) ◽  
pp. 38-48
Author(s):  
V. Badeli ◽  
G. M. Melito ◽  
A. Reinbacher-Köstinger ◽  
O. Bíró ◽  
K. Ellermann
Keyword(s):  
Aortic Dissection ◽  
Simulation Model ◽  
Impedance Cardiography ◽  
Patient Specific ◽  
Non Invasive ◽  
Impedance Cardiogram ◽  
Aortic Pathology ◽  
Invasive Method ◽  
Electrode Positioning ◽  
Transthoracic Electrical Impedance

AbstractImpedance cardiography (ICG) is a non-invasive method to evaluate several cardiodynamic parameters by measuring the cardiac-synchronous changes in the dynamic transthoracic electrical impedance. ICG allows us to identify and quantify conductivity changes inside the thorax by measuring the impedance on the thorax during a cardiac cycle. Pathologic changes in the aorta, like aortic dissection, will alter the aortic shape as well as the blood flow and consequently, the impedance cardiogram. This fact distorts the evaluated cardiodynamic parameters, but it could lead to the possibility to identify aortic pathology. A 3D numerical simulation model is used to compute the impedance changes on the thorax surface in case of the type B aortic dissection. A sensitivity analysis is applied using this simulation model to investigate the suitability of different electrode configurations considering several patient-specific cases. Results show that the remarkable pathological changes in the aorta caused by aortic dissection alters the impedance cardiogram significantly.

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