Abstract 102: Number of Reentry Tears Influences Flap Motion and Flow Reversal in an in vitro Model of Type B Aortic Dissection

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Joav Birjiniuk ◽  
Mark Young ◽  
Lucas H Timmins ◽  
Bradley G Leshnower ◽  
John N Oshinski ◽  
...  
Keyword(s):  
Aortic Dissection ◽  
False Lumen ◽  
Flow Reversal ◽  
Patient Specific ◽  
Type B ◽  
True Lumen ◽  
Flow Rates ◽  
Custom Made ◽  
Type B Dissection

Objectives: Aortic remodeling after dissection is poorly understood. Thus, optimal patient-specific recommendations for treatment are lacking. An in vitro aortic model of Type B dissection was used to interrogate local aortic hemodynamic parameters implicated in thrombosis and aneurysm formation. We hypothesize that dissections with multiple reentry tears will exhibit decreased flap motion, and, as a result, reduce flow reversal. Methods: Anatomic models of aortic dissection with fidelity to patient CT images were fabricated out of silicone. Models with primary entry and single fenestration (Figure 1A), two fenestrations (Figure 1B), and three fenestrations (Figure 1C) were installed in a flow loop. Physiologic flow was established at a cardiac index of 4 L/min. Flow velocities were acquired using phase contrast magnetic resonance (PCMR) imaging. Flow rates and flap motion were quantified using custom made software. Results: Relative true lumen area (RTLA) varied along the dissection (entry: 55% +/- 3, middle: 34% +/-7, exit: 91%+/-3, p<0.00001 pair-wise for 2-tear model). At mid-dissection, RTLA was lower in dissections with fewer tears (p<0.01). Total flow was nearly identical in all cases, while true and false lumen flow rates differed significantly across tear configurations and along the dissection (p<0.01). Secondary tears allowed for flow communication within the dissected portion of the aortic model. Flow reversal was seen in the false lumen at the mid-dissection plane in the absence of secondary tears (Figure 1D). However, as secondary tears were added, the flow reversal in the false lumen decreased, with concomitant flow reversal in the true lumen (Figure 1E,F). Conclusions: Anatomic characteristics of dissection, such as number of tears, affect blood flow and motion of the dissection flap, as shown quantitatively. This compliant aorta model illustrates alterations in flow reversal in both true and false lumina that may lead to aneurysmal degeneration.

scholarly journals Predicting false lumen thrombosis in patient-specific models of aortic dissection

2016 ◽  
Vol 13 (124) ◽  
pp. 20160759 ◽  
Author(s):  
Claudia Menichini ◽  
Zhuo Cheng ◽  
Richard G. J. Gibbs ◽  
Xiao Yun Xu
Keyword(s):  
Aortic Dissection ◽  
Clinical Decision Making ◽  
Thrombus Formation ◽  
False Lumen ◽  
Clinical Decision ◽  
Growth Patterns ◽  
Diffusion Reaction ◽  
Patient Specific ◽  
Type B ◽  
Type B Dissection

Aortic dissection causes splitting of the aortic wall layers, allowing blood to enter a ‘false lumen’ (FL). For type B dissection, a significant predictor of patient outcomes is patency or thrombosis of the FL. Yet, no methods are currently available to assess the chances of FL thrombosis. In this study, we present a new computational model that is capable of predicting thrombus formation, growth and its effects on blood flow under physiological conditions. Predictions of thrombus formation and growth are based on fluid shear rate, residence time and platelet distribution, which are evaluated through convection–diffusion–reaction transport equations. The model is applied to a patient-specific type B dissection for which multiple follow-up scans are available. The predicted thrombus formation and growth patterns are in good qualitative agreement with clinical data, demonstrating the potential applicability of the model in predicting FL thrombosis for individual patients. Our results show that the extent and location of thrombosis are strongly influenced by aortic dissection geometry that may change over time. The high computational efficiency of our model makes it feasible for clinical applications. By predicting which aortic dissection patient is more likely to develop FL thrombosis, the model has great potential to be used as part of a clinical decision-making tool to assess the need for early endovascular intervention for individual dissection patients.

scholarly journals The effect of beta-blockers on hemodynamic parameters in patient-specific blood flow simulations of type-B aortic dissection: a virtual study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mohammad Amin Abazari ◽  
Deniz Rafieianzab ◽  
M. Soltani ◽  
Mona Alimohammadi
Keyword(s):  
Aortic Dissection ◽  
Clinical Decision Making ◽  
Beta Blockers ◽  
False Lumen ◽  
Specific Treatment ◽  
Left Ventricular ◽  
Patient Specific ◽  
Type B ◽  
Windkessel Model ◽  
Computed Tomography Images

AbstractAortic dissection (AD) is one of the fatal and complex conditions. Since there is a lack of a specific treatment guideline for type-B AD, a better understanding of patient-specific hemodynamics and therapy outcomes can potentially control the progression of the disease and aid in the clinical decision-making process. In this work, a patient-specific geometry of type-B AD is reconstructed from computed tomography images, and a numerical simulation using personalised computational fluid dynamics (CFD) with three-element Windkessel model boundary condition at each outlet is implemented. According to the physiological response of beta-blockers to the reduction of left ventricular contractions, three case studies with different heart rates are created. Several hemodynamic features, including time-averaged wall shear stress (TAWSS), highly oscillatory, low magnitude shear (HOLMES), and flow pattern are investigated and compared between each case. Results show that decreasing TAWSS, which is caused by the reduction of the velocity gradient, prevents vessel wall at entry tear from rupture. Additionally, with the increase in HOLMES value at distal false lumen, calcification and plaque formation in the moderate and regular-heart rate cases are successfully controlled. This work demonstrates how CFD methods with non-invasive hemodynamic metrics can be developed to predict the hemodynamic changes before medication or other invasive operations. These consequences can be a powerful framework for clinicians and surgical communities to improve their diagnostic and pre-procedural planning.

A Novel Insight into the Role of Entry Tears in Type B Aortic Dissection: Pressure Measurements in an in Vitro Model

2017 ◽  
Vol 40 (10) ◽  
pp. 563-574 ◽  
Author(s):  
Stefania Marconi ◽  
Ettore Lanzarone ◽  
Hector De Beaufort ◽  
Michele Conti ◽  
Santi Trimarchi ◽  
...  
Keyword(s):  
False Lumen ◽  
Patient Characteristics ◽  
Acute Type ◽  
Type B ◽  
Type B Dissection ◽  
Vitro Model ◽  
Insight Into

Introduction Predicting aortic growth in acute type B dissection is fundamental in planning interventions. Several factors are considered to be growth predictors in the literature and, among them, size and location of entry tears have been recognized to particularly influence the false lumen pressure. In this study, we develop an in vitro setting to analyze the actual impact of size and location of the entry tears on false lumen pressure, in the absence of other confounding factors such as the deformability of the aortic wall. Methods We formalize some indexes that synthetically describe the false lumen pressure with respect to the true lumen pressure. Then, we experimentally derive their values in several configurations of the in vitro setting, and we look for trends in the indexes with respect to the size and location of entry tears. Results: Results show that the tears have a relevant impact on the false lumen pressure, but that their size and location alone are not enough to explain the phenomena observed in vivo. Conclusions To predict the behavior of acute type B dissection, we therefore recommend not limiting to size and location, as many effects may derive from the interactions between these parameters and other patient characteristics.

How to Exclude the Dilated False Lumen in Patients after a Type B Aortic Dissection? The Cork in the Bottleneck

2003 ◽  
Vol 10 (2) ◽  
pp. 244-248 ◽  
Author(s):  
Maartje C. Loubert ◽  
Victor P.M. van der Hulst ◽  
Cees De Vries ◽  
Kees Bloemendaal ◽  
Anco C. Vahl
Keyword(s):  
Aortic Dissection ◽  
Stent Graft ◽  
Case Reports ◽  
False Lumen ◽  
Type B ◽  
Type B Aortic Dissection ◽  
Type B Dissection ◽  
Occluder Device ◽  
Stent Graft Implantation ◽  
Graft Implantation

Purpose: To report techniques for excluding the dilated false lumen associated with chronic type B aortic dissection following placement of a stent-graft in the true lumen. Case Reports: Two patients underwent stent-graft implantation for a dilated false lumen after chronic aortic dissection, but the false lumen was not excluded from the circulation by this procedure. The false lumen was obliterated in one case with Greenfield filters and detachable balloons placed above a renal artery orifice that was perfused via the false lumen. This acted like “a cork in the bottleneck” to block retrograde flow into the thoracic portion of the false lumen above the blockade. In the other patient, an occluder device was used as the “cork.” In both cases, a good result was obtained. The occluder device is preferred because deployment is more controllable. Conclusions: An occluder device may be used like a cork in a bottle to exclude the dilated false lumen in the thoracic aorta after a type B dissection.

scholarly journals Aortic Geometric Alteration Associated With Acute Type B Aortic Dissection: Angulation, Tortuosity, and Arch Type

2021 ◽  
Vol 12 ◽  
Author(s):  
Likun Sun ◽  
Jiehua Li ◽  
Lunchang Wang ◽  
Quanming Li ◽  
Hao He ◽  
...  
Keyword(s):  
Aortic Dissection ◽  
Aortic Arch ◽  
False Lumen ◽  
Ascending Aorta ◽  
Acute Type ◽  
Type B ◽  
Type B Aortic Dissection ◽  
True Lumen ◽  
Factors Associated ◽  
Geometric Factors

Background: Acute type B aortic dissection is a highly serious aortic pathology. Aortic geometric parameters may be useful variables related to the occurrence of acute type B aortic dissection (aTBAD). The aim of the study is to delineate the alteration in aortic geometric parameters and analyze the specific geometric factors associated with aTBAD.Methods: The propensity score matching method was applied to control confounding factors. The aortic diameter, length, angulation, tortuosity, and type of aortic arch of the aTBAD and control group were retrospectively analyzed via three-dimensional computed tomography imaging created by the 3mensio software (version 10.0, Maastricht, The Netherlands). The geometric variables of true lumen and false lumen in the descending aorta were measured to estimate the severity of aortic dissection. Multivariable logistic regression models were used to investigate the significant and specific factors associated with aTBAD occurrence. The area under the receiver operating characteristic curve (AUC) was used to estimate the performance of the model.Results: After propensity score matching, 168 matched pairs of patients were selected. The ascending aorta and aortic arch diameters were dilated, and the ascending aorta and total aorta lengths were elongated in aTBAD group significantly (P &lt; 0.001). The ascending aorta and aortic arch angulations in the aTBAD group were sharper than those of the controls (P = 0.01, P &lt; 0.001, respectively). The aortic arch and total aorta tortuosities were significantly higher in the aTBAD group (P = 0.001, P &lt; 0.001, respectively). There were more type III arch patients in the aTBAD group than the controls (67.9 vs. 22.6%). The true lumen angulation was sharper than that in the false lumen (P &lt; 0.01). The true lumen tortuosity was significantly lower than that in the false lumen (P &lt; 0.001). The multivariable models identified that aortic arch angulation, tortuosity, and type III arch were independent and specific geometric factors associated with aTBAD occurrence. The AUC of the multivariable models 1, 2, 3 were 0.945, 0.953, and 0.96, respectively.Conclusions: The sharper angulation and higher tortuosity of aortic arch and type III arch were the geometric factors associated with aTBAD in addition to the ascending aorta elongation and aortic arch dilation. The angulation and tortuosity of the true and false lumens may carry significant clinical implications for the treatment and prognosis of aTBAD.

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.

scholarly journals A Combined In Vivo, In Vitro, In Silico Approach for Patient-Specific Haemodynamic Studies of Aortic Dissection

2020 ◽  
Vol 48 (12) ◽  
pp. 2950-2964
Author(s):  
Mirko Bonfanti ◽  
Gaia Franzetti ◽  
Shervanthi Homer-Vanniasinkam ◽  
Vanessa Díaz-Zuccarini ◽  
Stavroula Balabani
Keyword(s):  
Aortic Dissection ◽  
In Silico ◽  
Clinical Decision ◽  
Patient Specific ◽  
Type B ◽  
Non Invasive ◽  
Cfd Models ◽  
Numerical Predictions

AbstractThe optimal treatment of Type-B aortic dissection (AD) is still a subject of debate, with up to 50% of the cases developing late-term complications requiring invasive intervention. A better understanding of the patient-specific haemodynamic features of AD can provide useful insights on disease progression and support clinical management. In this work, a novel in vitro and in silico framework to perform personalised studies of AD, informed by non-invasive clinical data, is presented. A Type-B AD was investigated in silico using computational fluid dynamics (CFD) and in vitro by means of a state-of-the-art mock circulatory loop and particle image velocimetry (PIV). Both models not only reproduced the anatomical features of the patient, but also imposed physiologically-accurate and personalised boundary conditions. Experimental flow rate and pressure waveforms, as well as detailed velocity fields acquired via PIV, are extensively compared against numerical predictions at different locations in the aorta, showing excellent agreement. This work demonstrates how experimental and numerical tools can be developed in synergy to accurately reproduce patient-specific AD blood flow. The combined platform presented herein constitutes a powerful tool for advanced haemodynamic studies for a range of vascular conditions, allowing not only the validation of CFD models, but also clinical decision support, surgical planning as well as medical device innovation.

Deep Learning-Based 3D Segmentation of True Lumen, False Lumen, and False Lumen Thrombosis in Type-B Aortic Dissection

2021 ◽  
Author(s):  
Liana D. Wobben ◽  
Marina Codari ◽  
Gabriel Mistelbauer ◽  
Antonio Pepe ◽  
Kai Higashigaito ◽  
...  
Keyword(s):  
Deep Learning ◽  
Aortic Dissection ◽  
False Lumen ◽  
Type B ◽  
3D Segmentation ◽  
Type B Aortic Dissection ◽  
True Lumen

scholarly journals Intravascular Ultrasound–Assisted Endovascular Treatment of Mesenteric Malperfusion in a Multichannel Aortic Dissection With Full True Lumen Collapse

2018 ◽  
Vol 26 (1) ◽  
pp. 83-87 ◽  
Author(s):  
Baolei Guo ◽  
Daqiao Guo ◽  
Zhenyu Shi ◽  
Zhihui Dong ◽  
Weiguo Fu
Keyword(s):  
Aortic Dissection ◽  
Endovascular Treatment ◽  
Intravascular Ultrasound ◽  
Mesenteric Ischemia ◽  
False Lumen ◽  
Patient Specific ◽  
Chronic Mesenteric Ischemia ◽  
True Lumen ◽  
True Lumen Collapse ◽  
Ivus Imaging

Purpose: To describe endovascular treatment of mesenteric malperfusion in a multichannel aortic dissection (MCAD) with full true lumen (TL) collapse following thoracic endovascular aortic repair (TEVAR). Case Report: A 54-year-old man presented with chronic mesenteric ischemia and a previous TEVAR for MCAD complicated by superior mesenteric artery (SMA) malperfusion. Computed tomography angiography (CTA) demonstrated a 3-channel aortic dissection with a “false-true-false” configuration. The SMA was malperfused through the collapsed TL. CTA also showed a secondary entry tear, measuring 18 mm in diameter, at the end of the previous endograft. Direct open surgery or endovascular revascularization of the SMA was not feasible. A plan was devised to improve SMA perfusion by increasing the TL inflow. With the assistance of intravascular ultrasound (IVUS), an endograft was placed through one false lumen in the abdominal aorta and through the TL in the descending thoracic aorta to seal the secondary entry tear. Symptoms of mesenteric ischemia resolved 2 days after the procedure. At 1 year, he is asymptomatic, has gained weight, and has improved SMA perfusion and remodeling of the 3-channel dissection on CTA. Conclusion: IVUS imaging can help evaluate the complex hemodynamics of MCAD. Patient-specific endovascular treatment of MCAD with mesenteric malperfusion seems to be a feasible bailout alternative treatment for urgent, complex cases without reconstruction options.

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