Objective To evaluate the relationship between the CYP2C19 genotype and the antiplatelet effect o... more Objective To evaluate the relationship between the CYP2C19 genotype and the antiplatelet effect of clopidogrel therapy and to predict the risk of mid-term ischemic events after endovascular treatment of arteriosclerosis obliterans (ASO). Methods From January 2011 to July 2012, a total of seventy-four consecutive patients with ASO (TASCⅡA-C) in the superficial femoral artery (SFA) were included in a prospectively maintained database. Patients received a recommended dosage of 75 mg clopidogrel and 100 mg aspirin daily for at least 5 days prior to CYP2C19 single nucleotide polymorphisms TaqMan analysis and the thromboelastography assay of clopidogrel response, before endovascular procedure. Patients were divided into two groups according to CYP 2C19 genotypes. During the follow up, stent patency was assessed at 1-, 3-, 6-, and 12-month postoperatively. Results Fifty enrolled patients (67.6%) in the study were completely investigated in follow-up analysis. The mean duration of follow-up...
Zhonghua wai ke za zhi [Chinese journal of surgery], 2015
OBJECTIVE To evaluate the effect of extensive aortic diseases (EAD) after hybrid repair with supr... more OBJECTIVE To evaluate the effect of extensive aortic diseases (EAD) after hybrid repair with supra-arch branches or visceral arterial debranching and endovascular repair. METHODS A total of 24 EAD patients (19 male and 5 female) underwent hybrid repair in Department of Vascular Surgery, Zhongshan Hospital, Fudan University between March 2005 and April 2015. The clinical data was analyzed retrospectively. The mean age was (49±12) years (from 29 to 69 years). The high-risk candidates for open surgery were enrolled in the study. The patients, including 14 cases with thoracic aortic aneurysms and 10 cases with aortic dissection, were treated by one or two stages. Post-operative follow-up with CT angiography was performed at 3, 6 and 12 months and then annually thereafter. RESULTS A total of 74 branches, including 63 with visceral arteries and 11 with supra-arch arteries, were recanalized. Nine patients were treated in two-stage hybrid procedure and fifteen were repaired by one stage. Th...
Purpose: To describe endovascular treatment of mesenteric malperfusion in a multichannel aortic d... more 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 s...
Chronic mesenteric ischemia (CMI) is an uncommon condition encountered by clinicians. Presentatio... more Chronic mesenteric ischemia (CMI) is an uncommon condition encountered by clinicians. Presentation may vary from asymptomatic to classical intestinal ischemia, although a clear pathophysiology has yet to be elucidated. Here, we have presented our institution's experience in the management of symptomatic CMI. From February 2007 to February 2016, a retrospective study was performed of all consecutive patients with symptomatic CMI managed by endovascular treatment (ET). We reviewed these patients' demographics, comorbidities, clinical presentations, and treatment modalities. Perioperative and midterm outcomes included technical success, clinical symptom relief, complications, symptomatic recurrence, mortality, restenosis, and reintervention. Thirty-five mesenteric arteries (74.3% stenotic/25.7% occluded) identified in 32 patients (12 females, 20 males) were treated with endovascular procedures. There were no 30-day deaths; the perioperative complication rate was 12.5%. Overall,...
To compare the perioperative outcomes and mid-term survival rate between open surgery repair (OSR... more To compare the perioperative outcomes and mid-term survival rate between open surgery repair (OSR) and endovascular aneurysm repair (EVAR) of ruptured abdominal aortic aneurysms (RAAAs) in a Chinese population. A retrospective review was performed of the demographic characteristics and perioperative outcomes from 59 RAAA patients (mean 66.6 ± 13.3 years of age; 49 men) undergoing OSR or EVAR at our center between January 2003 and November 2014. The perioperative mortality and mid-term survival were assessed and compared between the OSR and EVAR groups. Twenty-three patients underwent OSR, and 36 patients underwent EVAR. The overall 30-day mortality was 36.5% (47.8% OSR vs. 27.8% EVAR; P=0.14). Total surgical time, estimated blood loss, and blood transfusion in the OSR group were significantly greater than those in the EVAR group (P<0.001). Reintervention within 30 days and during the follow-up was more frequent in the EVAR group (36.1%) than in the OSR group (8.7%; P=0.026). The ...
Interdisciplinary CardioVascular and Thoracic Surgery
OBJECTIVES Understanding morphology and how this relates to treatment strategy is critical for ac... more OBJECTIVES Understanding morphology and how this relates to treatment strategy is critical for achieving remodelling in aortic dissection. A controllable and reproducible large animal model is required for investigating new therapeutic devices and interventions. METHODS Our experimental protocol involved the development of surgically created type B aortic dissection (TBAD) and endovascular reintervention-induced TBAD porcine models. The sample was randomly divided into 2 groups: 1 underwent a secondary tear creation (STC) procedure and the other underwent a false lumen extension (FLE) procedure. Anatomical features were observed at 1 and 3 months, and 2 animals in each group were euthanized at 3 months after the procedures. The aorta and main branches were harvested en bloc, cross-sectioned and prepared for histological examination. RESULTS All surgically created TBAD models were successfully generated, and no unintended complications occurred. The endovascular reintervention-induce...
IEEE Transactions on Biomedical Engineering, Dec 1, 2019
Computational hemodynamics studies of aortic dissections usually combine patient-specific geometr... more Computational hemodynamics studies of aortic dissections usually combine patient-specific geometries with idealized or generic boundary conditions. In this study we present a comprehensive methodology for simulations of hemodynamics in type B aortic dissection (TBAD) based on fully patient-specific boundary conditions. Methods: Pre-operative 4D flow magnetic resonance imaging (MRI) and Doppler-wire pressure measurements (pre-and post-operative) were acquired from a TBAD patient. These data were used to derive boundary conditions for computational modelling of flow before and after thoracic endovascular repair (TEVAR). Validations of the computational results were performed by comparing predicted flow patterns with pre-TEVAR 4D flow MRI, as well as pressures with in vivo measurements. Results and Conclusion: Comparison of instantaneous velocity streamlines showed a good qualitative agreement with 4D flow MRI. Quantitative comparison of predicted pressures with pressure measurements revealed a maximum difference of 11 mmHg (-9.7%). Furthermore, our model correctly predicted the reduction of true lumen pressure from 74/115 mmHg pre-TEVAR to 64/107 mmHg post-TEVAR (diastolic/systolic pressures at entry tear level), compared to the corresponding measurements of 72/118 mmHg and 64/114 mmHg. This demonstrates that pre-TEVAR 4D flow MRI can be used to tune boundary conditions for post-TEVAR hemodynamic analyses.
European Journal of Vascular and Endovascular Surgery, Dec 1, 2021
Abdominal aortic aneurysms (AAAs) represent a vascular disease with severe complications. AAAs ar... more Abdominal aortic aneurysms (AAAs) represent a vascular disease with severe complications. AAAs are currently the overall 10th leading cause of death in western countries and their incidence is rising. Although different diagnostic techniques are currently available in clinical practice, including ultrasound (US), magnetic resonance imaging (MRI), and computed tomography (CT), imagingbased prediction of life-threatening complications such as aneurysm-rupture remains challenging. Molecular imaging provides a novel diagnostic approach for in vivo visualization of biological processes and pathological alterations at a cellular and molecular level. Its overall aim is to improve our understanding of disease pathogenesis and to facilitate novel diagnostic pathways. This review outlines recent preclinical and clinical developments in molecular MRI, positron emission tomography (PET), and single-photon emission computed tomography (SPECT) for imaging of AAAs. Abdominal Aortic Aneurysms AAAs represent a disease of the cardiovascular system that are mainly manifested in the infrarenal aorta. An AAA is defined as an irreversible dilatation of the aorta with a diameter greater than 30 mm, which represents an increase of more than 50% compared to the normal aortic diameter. With disease progression and enlargement of aortic diameter, the risk of AAA rupture increases [1]. Aortic rupture represents a life-threatening complication of aneurysms with an overall mortality rate of >90% in western countries [2]. The incidence of AAAs has been increasing steadily in most developed countries over the past decades, and rises to 3-4% in populations aged over 65 years [3].
Purpose: False lumen (FL) expansion often occurs in type B aortic dissection (TBAD) and has been ... more Purpose: False lumen (FL) expansion often occurs in type B aortic dissection (TBAD) and has been associated with the presence of re-entry tears. This longitudinal study aims to elucidate the role of re-entry tears in the progression of TBAD using a controlled swine model, by assessing aortic hemodynamics through combined imaging and computational modeling. Materials and Methods: A TBAD swine model with a primary entry tear at 7 cm distal to the left subclavian artery was created in a previous study. In the current study, reintervention was carried out in this swine model to induce 2 additional re-entry tears of approximately 5 mm in diameter. Computed tomography (CT) and 4-dimensional (4D) flow magnetic resonance imaging (MRI) scans were taken at multiple follow-ups before and after reintervention. Changes in aortic volume were measured on CT scans, and hemodynamic parameters were evaluated based on dynamic data acquired with 4D-flow MRI and computational fluid dynamics simulations ...
Quantitative assessment of the complex hemodynamic environment in type B aortic dissection (TBAD)... more Quantitative assessment of the complex hemodynamic environment in type B aortic dissection (TBAD) through computational fluid dynamics (CFD) simulations can provide detailed insights into the disease and its progression. As imaging and computational technologies have advanced, methodologies have been developed to increase the accuracy and physiological relevance of CFD simulations. This study presents a patient-specific workflow to simulate blood flow in TBAD, utilising the maximum amount of in vivo data available in the form of CT images, 4D-flow MRI and invasive Doppler-wire pressure measurements, to implement the recommended current best practice methodologies in terms of patient-specific geometry and boundary conditions. The study aimed to evaluate and verify this workflow through detailed qualitative and quantitative comparisons of the CFD and in vivo data. Based on data acquired from five TBAD patients, a range of essential model inputs was obtained, including inlet flow waveforms and 3-element Windkessel model parameters, which can be utilised in further studies where in vivo flow data is not available. Local and global analysis showed good consistency between CFD results and 4D-MRI data, with the maximum velocity in the primary entry tear differing by up to 0.3 m/s, and 80% of the analysed regions achieving moderate or strong correlations between the predicted and in vivo velocities. CFD predicted pressures were generally well matched to the Doppler-wire measurements, with some deviation in peak systolic values. Overall, this study presents a validated comprehensive workflow with extensive data for CFD simulation of TBAD.
In order for computational fluid dynamics to provide quantitative parameters to aid in the clinic... more In order for computational fluid dynamics to provide quantitative parameters to aid in the clinical assessment of type B aortic dissection, the results must accurately mimic the hemodynamic environment within the aorta. The choice of inlet velocity profile (IVP) therefore is crucial; however, idealised profiles are often adopted, and the effect of IVP on hemodynamics in a dissected aorta is unclear. This study examined two scenarios with respect to the influence of IVP—using (a) patient-specific data in the form of a three-directional (3D), through-plane (TP) or flat IVP; and (b) non-patient-specific flow waveform. The results obtained from nine simulations using patient-specific data showed that all forms of IVP were able to reproduce global flow patterns as observed with 4D flow magnetic resonance imaging. Differences in maximum velocity and time-averaged wall shear stress near the primary entry tear were up to 3% and 6%, respectively, while pressure differences across the true an...
Journal of Vascular and Interventional Radiology, 2020
Purpose: To report early and midterm outcomes of treating thoracic aortic aneurysm (TAA) and aort... more Purpose: To report early and midterm outcomes of treating thoracic aortic aneurysm (TAA) and aortic dissection (AD) involving zone 1 and zone 0 with multiple parallel stent grafts (PSGs). Materials and Methods: From February 2011 to August 2018, 31 of 1,806 patients (1.7%) who underwent thoracic endovascular aortic repair (TEVAR) with double PSGs (DPSGs) (n ¼ 20) or triple PSGs (TPSGs) (n ¼ 11) were retrospectively reviewed. Procedures were performed in high-risk patients who had TAA or AD involving zone 1 or zone 0. Results: Fifteen patients (48.4%) who presented with symptomatic or impending rupture underwent urgent or emergent TEVAR with DPSGs or TPSGs. Nineteen patients (61.3%) were treated for zone 0 disease. Technical and clinical success rates were 70.0% for DPSG cohort and 45.5% for TPSG cohort. Intraoperative type Ia endoleak was observed in 30% of DPSG cohort and 45.5% of TPSG cohort. One patient in the DPSG cohort died of aortic sinus rupture intraoperatively. Minor stroke during the 30-day postoperative period was more frequent in the TPSG cohort (P ¼ .042). Mean duration of follow-up was 28.9 months ± 17.7. The TPSG cohort had a higher incidence of major adverse events (72.7% vs 25.0%, P ¼ .021). The most common adverse events were endoleaks (12.9%), endograft migration (9.7%), PSG stenosis or occlusion (6.5%), retrograde dissection (6.5%), and stroke (3.2%). Endograft migrations were more common in TPSG cohort (27.3%, P ¼ .037). Overall mortality rate was 16.1% (5/31) perioperatively and during follow-up. There were no statistical differences in overall survival and reintervention-free survival. Conclusions: In the context of TEVAR with multiple PSGs for aortic arch repair, TPSGs may have a high risk of major complications.
Purpose: To explore the potential role of morphological factors and wall stress in the formation ... more Purpose: To explore the potential role of morphological factors and wall stress in the formation of stent-graft–induced new entries (SINE) based on computed tomography (CT) images after thoracic endovascular aortic repair (TEVAR). Case Report: Two female patients aged 59 years (patient 1) and 44 years (patient 2) underwent TEVAR for type B dissection in the chronic (patient 1) or subacute (patient 2) phase. CT scans at 3-month follow-up showed varying degrees of false lumen thrombosis in both patients. At 14-month follow-up, a SINE was observed in patient 1 while the dissected aorta in the other patient remained stable. Morphological and finite element analyses were performed based on the first follow-up CT images. The computational results showed that the SINE patient had higher stent-graft tortuosity than the non-SINE patient and much higher wall stress in the region close to the distal SINE. Conclusion: This case study suggests that high stent-graft tortuosity can lead to high wa...
European Journal of Vascular and Endovascular Surgery, 2019
OBJECTIVE Haemodynamic and geometric factors play pivotal roles in the propagation of acute type ... more OBJECTIVE Haemodynamic and geometric factors play pivotal roles in the propagation of acute type B aortic dissection (TBAD). The aim of this study was to evaluate the association between dissection level within all aortic layers and the propagation of acute TBAD in porcine aorta. METHODS Twelve pig acute TBAD models were created. In model A, the aortic wall tear was superficial and close to the intima (thin intimal flap), whereas in model B it was deep and close to the adventitia (thick intimal flap). Dissection propagation was evaluated using angiography or computed tomography scans, and the haemodynamic measurements were acquired using Doppler wires. Most pigs were followed up at 1, 3, 6, 12, 18, and up to 24 months; four animals were euthanised at three and six months, respectively (two from each group). RESULTS Both models were successfully created. No statistical difference was observed for the median antegrade propagation distance intra-operatively between the two models (p = .092). At 24 months, the longitudinal propagation distance was significantly greater in model B than in model A (p = .016). No statistical difference in retrograde propagation was noted (p = .691). Over time, aortic wall dissection progressed most notably over the first three months in model A, whereas it continued over the first 12 months in model B. Flow velocity was significantly greater in the true lumen than in false lumen at the level of the primary tear (p = .001) and in the middle of the dissection (p = .004). The histopathological images at three and six months demonstrated the fibres were stretched linearly at the outside wall of false lumen in both models, while the depth of intimal tears developed to be superficial and similar at the distal dissection. CONCLUSION In this swine model of TBAD, a deeper intimal tear resulted in greater dissection propagation.
This is an open access article distributed under the terms of the Creative Commons Attribution-No... more This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms.
Immediate type I and type III endoleaks after endovascular aneurysm repair (EVAR) could be persis... more Immediate type I and type III endoleaks after endovascular aneurysm repair (EVAR) could be persistent or temporary. Reintervention is necessary for persistent ones. Color-coded quantitative digital subtraction angiography (CQDSA) could provide a quantitative evaluation of the endoleak hemodynamics. We aimed to use CQDSA to quantify immediate type I and type III endoleaks after EVAR and to find a practical way to predict their outcomes. Between January 2012 and December 2014, 485 consecutive patients with abdominal aortic aneurysms underwent EVAR at our institution. Thirty-five patients (31 men, four women) with slight immediate type I and type III endoleaks after EVAR were recruited in the prospective observational nested case-control study. After at least 6 months of follow-up, these patients were divided into two groups based on endoleak-related adverse events. Their final intraprocedure DSA images were collected and converted into a single polychromatic image for CQDSA measuremen...
The treatment outcomes of symptomatic visceral artery aneurysms (SVAAs) have been sparsely charac... more The treatment outcomes of symptomatic visceral artery aneurysms (SVAAs) have been sparsely characterized, with no clear comparisons between different treatment modalities. The purpose of this study was to review the outcomes of SVAAs and asymptomatic visceral artery aneurysms (ASVAAs) after endovascular treatment (ET). The records of all patients with visceral artery aneurysms (VAAs) at our center from March 2004 to December 2014 were retrospectively reviewed. Patient demographics, aneurysm characteristics, management, perioperative and long-term outcomes, and complications were recorded. A total of 155 patients' records were reviewed; 106 patients (113 VAAs) were repaired with ET, including 27 symptomatic and 79 asymptomatic patients. The remaining 49 patients were treated with open surgery repair or conservative therapy. There was no significant difference of the diameters between SVAA and ASVAA (36.9 ± 15.3 mm vs 33.6 ± 36.1 mm, respectively; P = .746), and pseudoaneurysms we...
Journal of Vascular Surgery: Venous and Lymphatic Disorders, 2014
A 28-year-old man with a persistent cough and a mild fever was transferred to our institution. Co... more A 28-year-old man with a persistent cough and a mild fever was transferred to our institution. Computed tomography angiography showed a giant azygos venous aneurysm associated with the dilation of lumbar veins, azygos veins, hemiazygos veins, and intercostal veins (A-D). At the ages of 3 and 18 years, the man had undergone resection of angiomas in the chest wall (approximately 8 Â 8 Â 7 cm) and on the back (approximately 10 Â 8 Â 8.5 cm), respectively. The pathologic diagnosis showed cavernous hemangioma and lymphangioma. After the second operation, he was subsequently injected with ureaphil every 3 months for 18 times in total. However, the computed tomography scan at that time did not show the visible dilation of azygos veins and fertile varicose veins including intercostal veins, lumbar veins, and partial visceral veins, which was significantly different from that of 10 years later. Azygos venous aneurysms are extremely rare. Nakamura et al 1 reported three main types of azygos venous aneurysms caused by different factors. One of them was dilation of the azygos vein induced by increased venous pressure and volume load, as in the cases of heart failure, portal hypertension, right atrial mural thrombosis, and inferior vena caval occlusion. In this case, we believe it was induced by resection of hemangioma, which increased pressure and volume load. To the best of our knowledge, the giant azygos venous aneurysm caused by resection and embolization of cavernous hemangioma in the chest wall and back has never been reported. Azygos venous aneurysms may also be related to traumatic pseudoaneurysm and idiopathic saccular aneurysm. Its differential diagnosis should include other posterior mediastinal masses. However, Gomez et al 2 reported that if it is thrombosed, surgical therapy is necessary to prevent pulmonary embolism. A video-assisted thoracoscopic excision is recommended as the best technique. 3
Objective To evaluate the relationship between the CYP2C19 genotype and the antiplatelet effect o... more Objective To evaluate the relationship between the CYP2C19 genotype and the antiplatelet effect of clopidogrel therapy and to predict the risk of mid-term ischemic events after endovascular treatment of arteriosclerosis obliterans (ASO). Methods From January 2011 to July 2012, a total of seventy-four consecutive patients with ASO (TASCⅡA-C) in the superficial femoral artery (SFA) were included in a prospectively maintained database. Patients received a recommended dosage of 75 mg clopidogrel and 100 mg aspirin daily for at least 5 days prior to CYP2C19 single nucleotide polymorphisms TaqMan analysis and the thromboelastography assay of clopidogrel response, before endovascular procedure. Patients were divided into two groups according to CYP 2C19 genotypes. During the follow up, stent patency was assessed at 1-, 3-, 6-, and 12-month postoperatively. Results Fifty enrolled patients (67.6%) in the study were completely investigated in follow-up analysis. The mean duration of follow-up...
Zhonghua wai ke za zhi [Chinese journal of surgery], 2015
OBJECTIVE To evaluate the effect of extensive aortic diseases (EAD) after hybrid repair with supr... more OBJECTIVE To evaluate the effect of extensive aortic diseases (EAD) after hybrid repair with supra-arch branches or visceral arterial debranching and endovascular repair. METHODS A total of 24 EAD patients (19 male and 5 female) underwent hybrid repair in Department of Vascular Surgery, Zhongshan Hospital, Fudan University between March 2005 and April 2015. The clinical data was analyzed retrospectively. The mean age was (49±12) years (from 29 to 69 years). The high-risk candidates for open surgery were enrolled in the study. The patients, including 14 cases with thoracic aortic aneurysms and 10 cases with aortic dissection, were treated by one or two stages. Post-operative follow-up with CT angiography was performed at 3, 6 and 12 months and then annually thereafter. RESULTS A total of 74 branches, including 63 with visceral arteries and 11 with supra-arch arteries, were recanalized. Nine patients were treated in two-stage hybrid procedure and fifteen were repaired by one stage. Th...
Purpose: To describe endovascular treatment of mesenteric malperfusion in a multichannel aortic d... more 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 s...
Chronic mesenteric ischemia (CMI) is an uncommon condition encountered by clinicians. Presentatio... more Chronic mesenteric ischemia (CMI) is an uncommon condition encountered by clinicians. Presentation may vary from asymptomatic to classical intestinal ischemia, although a clear pathophysiology has yet to be elucidated. Here, we have presented our institution's experience in the management of symptomatic CMI. From February 2007 to February 2016, a retrospective study was performed of all consecutive patients with symptomatic CMI managed by endovascular treatment (ET). We reviewed these patients' demographics, comorbidities, clinical presentations, and treatment modalities. Perioperative and midterm outcomes included technical success, clinical symptom relief, complications, symptomatic recurrence, mortality, restenosis, and reintervention. Thirty-five mesenteric arteries (74.3% stenotic/25.7% occluded) identified in 32 patients (12 females, 20 males) were treated with endovascular procedures. There were no 30-day deaths; the perioperative complication rate was 12.5%. Overall,...
To compare the perioperative outcomes and mid-term survival rate between open surgery repair (OSR... more To compare the perioperative outcomes and mid-term survival rate between open surgery repair (OSR) and endovascular aneurysm repair (EVAR) of ruptured abdominal aortic aneurysms (RAAAs) in a Chinese population. A retrospective review was performed of the demographic characteristics and perioperative outcomes from 59 RAAA patients (mean 66.6 ± 13.3 years of age; 49 men) undergoing OSR or EVAR at our center between January 2003 and November 2014. The perioperative mortality and mid-term survival were assessed and compared between the OSR and EVAR groups. Twenty-three patients underwent OSR, and 36 patients underwent EVAR. The overall 30-day mortality was 36.5% (47.8% OSR vs. 27.8% EVAR; P=0.14). Total surgical time, estimated blood loss, and blood transfusion in the OSR group were significantly greater than those in the EVAR group (P<0.001). Reintervention within 30 days and during the follow-up was more frequent in the EVAR group (36.1%) than in the OSR group (8.7%; P=0.026). The ...
Interdisciplinary CardioVascular and Thoracic Surgery
OBJECTIVES Understanding morphology and how this relates to treatment strategy is critical for ac... more OBJECTIVES Understanding morphology and how this relates to treatment strategy is critical for achieving remodelling in aortic dissection. A controllable and reproducible large animal model is required for investigating new therapeutic devices and interventions. METHODS Our experimental protocol involved the development of surgically created type B aortic dissection (TBAD) and endovascular reintervention-induced TBAD porcine models. The sample was randomly divided into 2 groups: 1 underwent a secondary tear creation (STC) procedure and the other underwent a false lumen extension (FLE) procedure. Anatomical features were observed at 1 and 3 months, and 2 animals in each group were euthanized at 3 months after the procedures. The aorta and main branches were harvested en bloc, cross-sectioned and prepared for histological examination. RESULTS All surgically created TBAD models were successfully generated, and no unintended complications occurred. The endovascular reintervention-induce...
IEEE Transactions on Biomedical Engineering, Dec 1, 2019
Computational hemodynamics studies of aortic dissections usually combine patient-specific geometr... more Computational hemodynamics studies of aortic dissections usually combine patient-specific geometries with idealized or generic boundary conditions. In this study we present a comprehensive methodology for simulations of hemodynamics in type B aortic dissection (TBAD) based on fully patient-specific boundary conditions. Methods: Pre-operative 4D flow magnetic resonance imaging (MRI) and Doppler-wire pressure measurements (pre-and post-operative) were acquired from a TBAD patient. These data were used to derive boundary conditions for computational modelling of flow before and after thoracic endovascular repair (TEVAR). Validations of the computational results were performed by comparing predicted flow patterns with pre-TEVAR 4D flow MRI, as well as pressures with in vivo measurements. Results and Conclusion: Comparison of instantaneous velocity streamlines showed a good qualitative agreement with 4D flow MRI. Quantitative comparison of predicted pressures with pressure measurements revealed a maximum difference of 11 mmHg (-9.7%). Furthermore, our model correctly predicted the reduction of true lumen pressure from 74/115 mmHg pre-TEVAR to 64/107 mmHg post-TEVAR (diastolic/systolic pressures at entry tear level), compared to the corresponding measurements of 72/118 mmHg and 64/114 mmHg. This demonstrates that pre-TEVAR 4D flow MRI can be used to tune boundary conditions for post-TEVAR hemodynamic analyses.
European Journal of Vascular and Endovascular Surgery, Dec 1, 2021
Abdominal aortic aneurysms (AAAs) represent a vascular disease with severe complications. AAAs ar... more Abdominal aortic aneurysms (AAAs) represent a vascular disease with severe complications. AAAs are currently the overall 10th leading cause of death in western countries and their incidence is rising. Although different diagnostic techniques are currently available in clinical practice, including ultrasound (US), magnetic resonance imaging (MRI), and computed tomography (CT), imagingbased prediction of life-threatening complications such as aneurysm-rupture remains challenging. Molecular imaging provides a novel diagnostic approach for in vivo visualization of biological processes and pathological alterations at a cellular and molecular level. Its overall aim is to improve our understanding of disease pathogenesis and to facilitate novel diagnostic pathways. This review outlines recent preclinical and clinical developments in molecular MRI, positron emission tomography (PET), and single-photon emission computed tomography (SPECT) for imaging of AAAs. Abdominal Aortic Aneurysms AAAs represent a disease of the cardiovascular system that are mainly manifested in the infrarenal aorta. An AAA is defined as an irreversible dilatation of the aorta with a diameter greater than 30 mm, which represents an increase of more than 50% compared to the normal aortic diameter. With disease progression and enlargement of aortic diameter, the risk of AAA rupture increases [1]. Aortic rupture represents a life-threatening complication of aneurysms with an overall mortality rate of >90% in western countries [2]. The incidence of AAAs has been increasing steadily in most developed countries over the past decades, and rises to 3-4% in populations aged over 65 years [3].
Purpose: False lumen (FL) expansion often occurs in type B aortic dissection (TBAD) and has been ... more Purpose: False lumen (FL) expansion often occurs in type B aortic dissection (TBAD) and has been associated with the presence of re-entry tears. This longitudinal study aims to elucidate the role of re-entry tears in the progression of TBAD using a controlled swine model, by assessing aortic hemodynamics through combined imaging and computational modeling. Materials and Methods: A TBAD swine model with a primary entry tear at 7 cm distal to the left subclavian artery was created in a previous study. In the current study, reintervention was carried out in this swine model to induce 2 additional re-entry tears of approximately 5 mm in diameter. Computed tomography (CT) and 4-dimensional (4D) flow magnetic resonance imaging (MRI) scans were taken at multiple follow-ups before and after reintervention. Changes in aortic volume were measured on CT scans, and hemodynamic parameters were evaluated based on dynamic data acquired with 4D-flow MRI and computational fluid dynamics simulations ...
Quantitative assessment of the complex hemodynamic environment in type B aortic dissection (TBAD)... more Quantitative assessment of the complex hemodynamic environment in type B aortic dissection (TBAD) through computational fluid dynamics (CFD) simulations can provide detailed insights into the disease and its progression. As imaging and computational technologies have advanced, methodologies have been developed to increase the accuracy and physiological relevance of CFD simulations. This study presents a patient-specific workflow to simulate blood flow in TBAD, utilising the maximum amount of in vivo data available in the form of CT images, 4D-flow MRI and invasive Doppler-wire pressure measurements, to implement the recommended current best practice methodologies in terms of patient-specific geometry and boundary conditions. The study aimed to evaluate and verify this workflow through detailed qualitative and quantitative comparisons of the CFD and in vivo data. Based on data acquired from five TBAD patients, a range of essential model inputs was obtained, including inlet flow waveforms and 3-element Windkessel model parameters, which can be utilised in further studies where in vivo flow data is not available. Local and global analysis showed good consistency between CFD results and 4D-MRI data, with the maximum velocity in the primary entry tear differing by up to 0.3 m/s, and 80% of the analysed regions achieving moderate or strong correlations between the predicted and in vivo velocities. CFD predicted pressures were generally well matched to the Doppler-wire measurements, with some deviation in peak systolic values. Overall, this study presents a validated comprehensive workflow with extensive data for CFD simulation of TBAD.
In order for computational fluid dynamics to provide quantitative parameters to aid in the clinic... more In order for computational fluid dynamics to provide quantitative parameters to aid in the clinical assessment of type B aortic dissection, the results must accurately mimic the hemodynamic environment within the aorta. The choice of inlet velocity profile (IVP) therefore is crucial; however, idealised profiles are often adopted, and the effect of IVP on hemodynamics in a dissected aorta is unclear. This study examined two scenarios with respect to the influence of IVP—using (a) patient-specific data in the form of a three-directional (3D), through-plane (TP) or flat IVP; and (b) non-patient-specific flow waveform. The results obtained from nine simulations using patient-specific data showed that all forms of IVP were able to reproduce global flow patterns as observed with 4D flow magnetic resonance imaging. Differences in maximum velocity and time-averaged wall shear stress near the primary entry tear were up to 3% and 6%, respectively, while pressure differences across the true an...
Journal of Vascular and Interventional Radiology, 2020
Purpose: To report early and midterm outcomes of treating thoracic aortic aneurysm (TAA) and aort... more Purpose: To report early and midterm outcomes of treating thoracic aortic aneurysm (TAA) and aortic dissection (AD) involving zone 1 and zone 0 with multiple parallel stent grafts (PSGs). Materials and Methods: From February 2011 to August 2018, 31 of 1,806 patients (1.7%) who underwent thoracic endovascular aortic repair (TEVAR) with double PSGs (DPSGs) (n ¼ 20) or triple PSGs (TPSGs) (n ¼ 11) were retrospectively reviewed. Procedures were performed in high-risk patients who had TAA or AD involving zone 1 or zone 0. Results: Fifteen patients (48.4%) who presented with symptomatic or impending rupture underwent urgent or emergent TEVAR with DPSGs or TPSGs. Nineteen patients (61.3%) were treated for zone 0 disease. Technical and clinical success rates were 70.0% for DPSG cohort and 45.5% for TPSG cohort. Intraoperative type Ia endoleak was observed in 30% of DPSG cohort and 45.5% of TPSG cohort. One patient in the DPSG cohort died of aortic sinus rupture intraoperatively. Minor stroke during the 30-day postoperative period was more frequent in the TPSG cohort (P ¼ .042). Mean duration of follow-up was 28.9 months ± 17.7. The TPSG cohort had a higher incidence of major adverse events (72.7% vs 25.0%, P ¼ .021). The most common adverse events were endoleaks (12.9%), endograft migration (9.7%), PSG stenosis or occlusion (6.5%), retrograde dissection (6.5%), and stroke (3.2%). Endograft migrations were more common in TPSG cohort (27.3%, P ¼ .037). Overall mortality rate was 16.1% (5/31) perioperatively and during follow-up. There were no statistical differences in overall survival and reintervention-free survival. Conclusions: In the context of TEVAR with multiple PSGs for aortic arch repair, TPSGs may have a high risk of major complications.
Purpose: To explore the potential role of morphological factors and wall stress in the formation ... more Purpose: To explore the potential role of morphological factors and wall stress in the formation of stent-graft–induced new entries (SINE) based on computed tomography (CT) images after thoracic endovascular aortic repair (TEVAR). Case Report: Two female patients aged 59 years (patient 1) and 44 years (patient 2) underwent TEVAR for type B dissection in the chronic (patient 1) or subacute (patient 2) phase. CT scans at 3-month follow-up showed varying degrees of false lumen thrombosis in both patients. At 14-month follow-up, a SINE was observed in patient 1 while the dissected aorta in the other patient remained stable. Morphological and finite element analyses were performed based on the first follow-up CT images. The computational results showed that the SINE patient had higher stent-graft tortuosity than the non-SINE patient and much higher wall stress in the region close to the distal SINE. Conclusion: This case study suggests that high stent-graft tortuosity can lead to high wa...
European Journal of Vascular and Endovascular Surgery, 2019
OBJECTIVE Haemodynamic and geometric factors play pivotal roles in the propagation of acute type ... more OBJECTIVE Haemodynamic and geometric factors play pivotal roles in the propagation of acute type B aortic dissection (TBAD). The aim of this study was to evaluate the association between dissection level within all aortic layers and the propagation of acute TBAD in porcine aorta. METHODS Twelve pig acute TBAD models were created. In model A, the aortic wall tear was superficial and close to the intima (thin intimal flap), whereas in model B it was deep and close to the adventitia (thick intimal flap). Dissection propagation was evaluated using angiography or computed tomography scans, and the haemodynamic measurements were acquired using Doppler wires. Most pigs were followed up at 1, 3, 6, 12, 18, and up to 24 months; four animals were euthanised at three and six months, respectively (two from each group). RESULTS Both models were successfully created. No statistical difference was observed for the median antegrade propagation distance intra-operatively between the two models (p = .092). At 24 months, the longitudinal propagation distance was significantly greater in model B than in model A (p = .016). No statistical difference in retrograde propagation was noted (p = .691). Over time, aortic wall dissection progressed most notably over the first three months in model A, whereas it continued over the first 12 months in model B. Flow velocity was significantly greater in the true lumen than in false lumen at the level of the primary tear (p = .001) and in the middle of the dissection (p = .004). The histopathological images at three and six months demonstrated the fibres were stretched linearly at the outside wall of false lumen in both models, while the depth of intimal tears developed to be superficial and similar at the distal dissection. CONCLUSION In this swine model of TBAD, a deeper intimal tear resulted in greater dissection propagation.
This is an open access article distributed under the terms of the Creative Commons Attribution-No... more This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms.
Immediate type I and type III endoleaks after endovascular aneurysm repair (EVAR) could be persis... more Immediate type I and type III endoleaks after endovascular aneurysm repair (EVAR) could be persistent or temporary. Reintervention is necessary for persistent ones. Color-coded quantitative digital subtraction angiography (CQDSA) could provide a quantitative evaluation of the endoleak hemodynamics. We aimed to use CQDSA to quantify immediate type I and type III endoleaks after EVAR and to find a practical way to predict their outcomes. Between January 2012 and December 2014, 485 consecutive patients with abdominal aortic aneurysms underwent EVAR at our institution. Thirty-five patients (31 men, four women) with slight immediate type I and type III endoleaks after EVAR were recruited in the prospective observational nested case-control study. After at least 6 months of follow-up, these patients were divided into two groups based on endoleak-related adverse events. Their final intraprocedure DSA images were collected and converted into a single polychromatic image for CQDSA measuremen...
The treatment outcomes of symptomatic visceral artery aneurysms (SVAAs) have been sparsely charac... more The treatment outcomes of symptomatic visceral artery aneurysms (SVAAs) have been sparsely characterized, with no clear comparisons between different treatment modalities. The purpose of this study was to review the outcomes of SVAAs and asymptomatic visceral artery aneurysms (ASVAAs) after endovascular treatment (ET). The records of all patients with visceral artery aneurysms (VAAs) at our center from March 2004 to December 2014 were retrospectively reviewed. Patient demographics, aneurysm characteristics, management, perioperative and long-term outcomes, and complications were recorded. A total of 155 patients' records were reviewed; 106 patients (113 VAAs) were repaired with ET, including 27 symptomatic and 79 asymptomatic patients. The remaining 49 patients were treated with open surgery repair or conservative therapy. There was no significant difference of the diameters between SVAA and ASVAA (36.9 ± 15.3 mm vs 33.6 ± 36.1 mm, respectively; P = .746), and pseudoaneurysms we...
Journal of Vascular Surgery: Venous and Lymphatic Disorders, 2014
A 28-year-old man with a persistent cough and a mild fever was transferred to our institution. Co... more A 28-year-old man with a persistent cough and a mild fever was transferred to our institution. Computed tomography angiography showed a giant azygos venous aneurysm associated with the dilation of lumbar veins, azygos veins, hemiazygos veins, and intercostal veins (A-D). At the ages of 3 and 18 years, the man had undergone resection of angiomas in the chest wall (approximately 8 Â 8 Â 7 cm) and on the back (approximately 10 Â 8 Â 8.5 cm), respectively. The pathologic diagnosis showed cavernous hemangioma and lymphangioma. After the second operation, he was subsequently injected with ureaphil every 3 months for 18 times in total. However, the computed tomography scan at that time did not show the visible dilation of azygos veins and fertile varicose veins including intercostal veins, lumbar veins, and partial visceral veins, which was significantly different from that of 10 years later. Azygos venous aneurysms are extremely rare. Nakamura et al 1 reported three main types of azygos venous aneurysms caused by different factors. One of them was dilation of the azygos vein induced by increased venous pressure and volume load, as in the cases of heart failure, portal hypertension, right atrial mural thrombosis, and inferior vena caval occlusion. In this case, we believe it was induced by resection of hemangioma, which increased pressure and volume load. To the best of our knowledge, the giant azygos venous aneurysm caused by resection and embolization of cavernous hemangioma in the chest wall and back has never been reported. Azygos venous aneurysms may also be related to traumatic pseudoaneurysm and idiopathic saccular aneurysm. Its differential diagnosis should include other posterior mediastinal masses. However, Gomez et al 2 reported that if it is thrombosed, surgical therapy is necessary to prevent pulmonary embolism. A video-assisted thoracoscopic excision is recommended as the best technique. 3
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