Computational Investigation and Histopathological Validation of Interaction Between Stent Graft and Aorta in Retrograde Type A Dissection After TEVAR in Canine Models.

PURPOSE: Retrograde type A dissection (RTAD) after thoracic endovascular aortic repair (TEVAR) has been a major drawback of endovascular treatment. To our knowledge, no studies have simulated and validated aortic injuries caused by stent grafts (SGs) in animal models. Therefore, the aim of this study was to evaluate and quantify the SG-aorta interaction through computational simulations and to investigate the underlying mechanism through histopathological examinations. METHODS: Two custom-made Fabulous® (DiNovA Meditech, Hang Zhou, China) SGs were implanted in 2 canine aortas with a 5-mm difference in the distance in landing locations. The aortic geometries were extracted from RTAD and non-RTAD cases. A computational SG model was assembled based on the implanted SG using the software Pro-ENGINEER Wildfire 5.0 (PTC Corporation, Needham, Mass). TEVAR simulations were performed 7 times for each canine model using Abaqus software (Providence, RI, USA), and the maximum aortic stress (MAS) was calculated and compared among the groups. Three months after SG implantation, the canine aortas were harvested, and were examined using hematoxylin and eosin staining and Elastica Van Gieson (EVG) staining to evaluate histopathological changes. RESULTS: In the computational models for both canines, MAS was observed at the proximal bare stent (PBS) at aortic greater curve. The PBS generated higher stress toward the aortic wall than other SG parts did. Moreover, the MAS was significantly higher in canine No.1 than in canine No.2 (0.415±0.210 versus 0.200±0.160 MPa) (p<0.01). Notably, in canine No.1, an RTAD developed at the MAS segment, and histopathological examinations of the segment showed an intimal flap, a false lumen, elastin changes, and medial necrosis. RTAD was not observed in canine No.2. In both SG-covered aortas, medial necrosis, elastic fiber stretching, and inflammatory infiltration were seen. CONCLUSION: The characteristic MAS distribution remained at the location where the apex of the PBS interacted with the aortic wall at greater curve. RTAD histopathological examinations showed intimal damage and medial necrosis at the proximal landing zone, at the same MAS location in computational simulations. The in vivo results were consistent with the computational simulations, suggesting the MAS at greater curve may cause RTAD, and the potential application of computational simulation in the mechanism study of RTAD.

Preoperative high lymphocyte-to-monocyte ratio is associated with intraoperative type I endoleak in patients with TAA with TEVAR.

OBJECTIVES: Various inflammatory factors are closely associated with the incidence of thoracic aortic aneurysms (TAAs). Furthermore, the severity of inflammation is closely related to the absolute value and proportion of each leukocyte subgroup. Only few reports have analyzed the importance of lymphocyte-monocyte ratio (LMR) as a potential inflammatory marker in vascular diseases. Therefore, we aimed to investigate the effect of peripheral blood LMR on thoracic endovascular aortic repair (TEVAR) in patients with TAA. METHODS: A retrospective study of the clinical data collected in our hospital between January 2016 and January 2021 was performed on 162 patients with TAA treated with TEVAR, based on the inclusion and exclusion criteria for patient selection. Based on whether the patient had the clinical symptoms at admission and the occurrence of type I endoleaks during operation, patients were divided into two groups, respectively: an intraoperative type I endoleak group (n = 34) and a group without intraoperative type I endoleak (n = 128), and a group with clinical symptoms (n = 31) and a group without clinical symptoms (n = 131). The clinical data of these two groups were compared, the free from second intervention rates related to endoleak and the preoperatively LMR of the two groups was calculated. LMR was calculated preoperatively. Receiver-operating characteristic curve analysis was used to determine the cut-off for preoperative LMR values. Based on the cut-off point, patients were divided into a high LMR group (n = 34) and a low LMR group (n = 128). The clinical data of the two groups were compared, and further stratified analysis was performed. RESULTS: A total of 162 patients were included in the analysis. All patients were successfully implanted with a thoracic aorta stent graft. The preoperative LMR level and postoperative endoleak-related secondary intervention rate were higher in the type I endoleak group than those in the group without intraoperative type I endoleaks. The preoperative C-reactive protein (CRP) level of patients with TAA with clinical symptoms was higher than that of asymptomatic patients. There was a negative correlation between preoperative CRP and LMR levels. In addition, in symptomatic or asymptomatic patients, the LMR level was associated with the occurrence of intraoperative type I endoleaks. After excluding the influence of type of endografts, our results showed that the clinical symptoms did not affect the occurrence of the intraoperative type I endoleak, and patients with intraoperative type I endoleak had a higher rate of postoperative secondary intervention. CONCLUSION: Patients with TAA with type I endoleaks during TEVAR had an increased rate of secondary intervention related to endoleaks. Patients with TAA with high LMR levels before TEVAR were more likely to have endoleaks during operation.

Intraoperative Stent-Graft-Induced Aortic Intimal Intussusception During TEVAR for Type B Aortic Dissection.

BACKGROUND: Aortic intimal intussusception is well described in the natural progression of type A aortic dissection. Only 3 cases of aortic intimal intussusception were reported to be related to thoracic endovascular aortic repair (TEVAR) for Stanford type B aortic dissection. In our study, we are reporting a rare but potentially fatal complication, the intraoperative stent-graft (SG)-induced aortic intimal intussusception (ISAII); this study reports a series of endovascular repair for ISAII cases. By presenting the ISAII definition, the diagnostic steps to rule out or to identify the condition, and the techniques to resolve it, we intended to raise the awareness of this severe complication, so that physicians can adapt to overcome the complications while performing TEVAR. MATERIALS AND METHODS: ISAII was defined as the partial or circumferential disruption of the distal intimal flap as an intraoperative complication of endovascular treatment. From January 2014 to June 2020, 1,096 patients underwent TEVAR for Stanford type B aortic dissection at our hospital. Among them, 14 ISAII complications were witnessed. All these patients underwent endovascular repair for ISAII lesions, and their data were extracted for analysis. RESULTS: The ISAII lesions were classified into 3 types according to their location in different aortic segments: type I, ISAII was limited within the intended SG coverage segment; type II, ISAII occurred after SG introduction or deployment, and the detached intimal flap extended beyond the intended SG coverage segment but did not affect the abdominal aortic visceral branches; type III, ISAII occurred during SG introduction or deployment, and the detached intimal flap descended to the abdominal aortic segment with visceral branches. Our results showed ISAII as a rare complication with an incidence of 1.28% (14/1096), and endovascular repair for all types of ISAII is an effective treatment. With a mean follow-up of 27.36 months (range 5-71 months), all the ISAII lesions were stable, and all the major aortic branches, SGs, and bare stents were patent. CONCLUSIONS: The management of this potentially devastating intraoperative complication relies on accurate diagnosis and prompt management. Our results suggested that endovascular repair for ISAII is effective and durable for correcting this complication. GRAPHICAL ABSTRACT: [Formula: see text].

Long-term results of extensive aortoiliac occlusive disease (EAIOD) treated by endovascular therapy and risk factors for loss of primary patency.

BACKGROUND: Although endovascular therapy has been widely used for focal aortoiliac occlusive disease (AIOD), its performance for extensive AIOD (EAIOD) is not fully evaluated. We aimed to demonstrate the long-term results of EAIOD treated by endovascular therapy and to identify the potential risk factors for the loss of primary patency. METHODS: Between January 2008 and June 2018, patients with a clinical diagnosis of the 2007 TransAtlantic Inter-Society Consensus II (TASC II) C and D AIOD lesions who underwent endovascular treatment in our institution were enrolled. Demographic, diagnosis, procedure characteristics, and follow-up information were reviewed. Univariate analysis was used to identify the correlation between the variables and the primary patency. A multivariate logistic regression model was used to identify the independent risk factors associated with primary patency. Five- and 10-year primary and secondary patency, as well as survival rates, were calculated by Kaplan-Meier analysis. RESULTS: A total of 148 patients underwent endovascular treatment in our center. Of these, 39.2% were classified as having TASC II C lesions and 60.8% as having TASC II D lesions. The technical success rate was 88.5%. The mean follow-up time was 79.2 ±â€Š29.2 months. Primary and secondary patency was 82.1% and 89.4% at 5 years, and 74.8% and 83.1% at 10 years, respectively. The 5-year survival rate was 84.2%. Compared with patients without loss of primary patency, patients with this condition showed significant differences in age, TASC II classification, infrainguinal lesions, critical limb ischemia (CLI), and smoking. Multivariate logistic regression analysis showed age <61 years (adjusted odds ratio [aOR]: 6.47; 95% CI: 1.47-28.36; P = 0.01), CLI (aOR: 7.81; 95% CI: 1.92-31.89; P = 0.04), and smoking (aOR: 10.15; 95% CI: 2.79-36.90; P < 0.01) were independent risk factors for the loss of primary patency. CONCLUSION: Endovascular therapy was an effective treatment for EAIOD with encouraging patency and survival rate. Age <61 years, CLI, and smoking were independent risk factors for the loss of primary patency.

Viral metagenomics revealed diverse CRESS-DNA virus genomes in faeces of forest musk deer.

BACKGROUND: Musk deer can produce musk which has high medicinal value and is closely related to human health. Viruses in forest musk deer both threaten the health of forest musk deer and human beings. METHODS: Using viral metagenomics we investigated the virome in 85 faeces samples collected from forest musk deer. RESULTS: In this article, eight novel CRESS-DNA viruses were characterized, whole genomes were 2148 nt-3852 nt in length. Phylogenetic analysis indicated that some viral genomes were part of four different groups of CRESS-DNA virus belonging in the unclassified CRESS-DNA virus, Smacoviridae, pCPa-like virus and pPAPh2-like virus. UJSL001 (MN621482), UJSL003 (MN621469) and UJSL017 (MN621476) fall into the branch of unclassified CRESS-DNA virus (CRESSV1-2), UJSL002 (MN621468), UJSL004 (MN621481) and UJSL007 (MN621470) belong to the cluster of Smacoviridae, UJSL005 (MN604398) showing close relationship with pCPa-like (pCRESS4-8) clusters and UJSL006 (MN621480) clustered into the branch of pPAPh2-like (pCRESS9) virus, respectively. CONCLUSION: The virome in faeces samples of forest musk deer from Chengdu, Sichuan province, China was revealed, which further characterized the diversity of viruses in forest musk deer intestinal tract.

Comparison between paclitaxel-coated balloon and standard uncoated balloon in the treatment of femoropopliteal long lesions in diabetics.

Atherosclerotic diseases may include femoropopliteal artery stenosis or occlusion. Percutaneous transluminal angioplasty (PTA) is an effective and minimally invasive treatment strategy for atherosclerotic femoropopliteal artery stenosis/occlusion disease. Balloon angioplasty is a widely used technique in the management of occlusive disease in almost all arterial segments.We enrolled 111 diabetics with long femoropopliteal lesions, among which 54 received PTA with paclitaxel-coated balloon (the Paclitaxel group), and 57 with standard balloon catheters (the Control group).The primary outcome was set as angiographic late lumen loss (LLL) within 6 months; the secondary angiographic outcome was binary restenosis. Clinical outcomes included Rutherford clarification, ankle-brachial index (ABI) and rate of clinically driven target lesion revascularization (TLR). Two groups had similar basal clinical features, angiographic and procedural characteristics. Compared to controls, the Paclitaxel group had a significantly lower 6-month LLL rate, 12-month binary restenosis rate, 12-month TLR, lower Rutherford grades at 3 and 6 months, and higher ABI at 3 months. For all factors which might influence outcomes, fasting blood glucose was negatively correlated with ABI; the blood urea nitrogen (BUN) was positively related with the Rutherford clarification grades. In addition, the coronary heart disease (CHD) and smoking histories were positively correlated with residual stenosis after treatment.Collectively, the paclitaxel-coated balloon angioplasty can yield more favorable angiographic and clinical outcomes than standard uncoated balloon angioplasty, even in the more challenging lesions (the long and occlusive femoropopliteal lesions) in diabetics, when it had a similar safety profile to the traditional balloon. Blood glucose, BUN, CHD, and smoking imply poor curative effects.

Computational investigation of interaction between stent graft and aorta in retrograde type A dissection after thoracic endovascular aortic repair for type B aortic dissection.

OBJECTIVE: Retrograde type A dissection (RTAD) after thoracic endovascular aortic repair (TEVAR) has been a major drawback of endovascular treatment. To our knowledge, no studies have evaluated aortic injuries caused by stent grafts (SGs). Therefore, the aim of this study was to evaluate and to quantify the SG-aorta interaction and to analyze the risk factors for injury through computational simulation. METHODS: The aortic geometry was extracted from an RTAD case. Five SG models were assembled based on Valiant and Talent (Medtronic Vascular, Santa Rosa, Calif) SGs, and modifications were made to the original SG design by adding and removing the connecting bar. TEVAR simulations were performed seven times for each SG model with 0% and 15% oversizing ratio (OSR), and the maximum aortic stress (MAS) was calculated and compared within the groups. RESULTS: In all TEVAR models, MAS was seen at the proximal bare stent (PBS). The PBS in the Valiant and Talent SGs generated higher stress toward the aortic wall than other SG parts did. MAS was significantly higher for the 15% OSR (0.54 ± 0.07 MPa) than for the 0% OSR (1.32 ± 0.74 MPa) in 172.5-mm Valiant models. MAS was significantly higher in the Talent with connecting bar SG model (0.73 ± 0.24 MPa) than in the Talent without connecting bar SG model (0.51 ± 0.11 MPa). MAS was significantly higher in the Valiant with connecting bar SG model (0.82 ± 0.29 MPa) than in the Valiant without connecting bar SG model (0.54 ± 0.07 MPa). MAS was not significantly different in models with 172.5-mm and 140-mm Valiant SG implantations with 0% OSR (0.54 ± 0.07 MPa vs 0.60 ± 0.12 MPa) and 15% OSR (1.32 ± 0.74 MPa vs 1.12 ± 0.33 MPa). CONCLUSIONS: The characteristic MAS distribution remained at the location where the apexes of the PBS interacted with the aortic wall at its greater curve. Both higher OSR and the presence of a connecting bar can significantly increase the MAS after SG implantation. Moreover, the chronic MAS at the PBS area may injure the aortic wall, causing RTAD.

Incidence and risk factors for retrograde type A dissection and stent graft-induced new entry after thoracic endovascular aortic repair.

OBJECTIVE: Stent graft (SG)-induced new entry (SINE) and retrograde type A dissection (RTAD) are serious device-related complications occurring after thoracic endovascular aortic repair (TEVAR) for Stanford type B aortic dissection (TBAD) and may lead to endograft-related complications including retrograde dissection and death. The purpose of this study was to investigate the incidence and risk factors for the development of RTAD and SINE after TEVAR for TBAD and to identify the complications associated with this. METHODS: From April 2005 to October 2013, there were 997 patients who underwent TEVAR for TBAD; 852 were followed up (0-6 years; mean, 2.6 years), and 59 SINEs developed in 53 patients. The oversizing ratio and incidence of RTAD and SINE were compared between proximal bare stent (PBS) and non-PBS groups and RTAD and SINE and non-RTAD and non-SINE groups. The baseline characteristics and SG configurational factors potentially affecting both RTAD and distal SINE were analyzed. RESULTS: There was no significant difference between PBS and non-PBS groups in the incidence of RTAD. A greater oversizing ratio was related to a higher distal SINE rate. SINE was seen more frequently in smokers and in patients with hypertension, Marfan syndrome, and TEVAR in the chronic phase and less frequently in complicated dissection cases. Device-related factors for SINE were SG with a connecting bar and SG length <165 mm. The SG length <165 mm increased the overall proximal and distal SINE incidence in multivariate analysis. CONCLUSIONS: The presence of a PBS is not associated with a higher RTAD rate, whereas the use of an SG with a connecting bar and length <165 mm increases the risk of RTAD and SINE after TEVAR.

Endovascular Management of a Ruptured Aortic Arch Pseudoaneurysm Using the Snorkel Technique and Coil Embolization.

We report a reoperation case of a ruptured infectious aortic arch pseudoaneurysm, which was stabilized with thoracic endovascular aortic repair and snorkel bypass of the innominate artery (IA) and the left common carotid artery (LCCA). A 57-year-old Chinese woman with multiple comorbidities and previous open repair for Stanford type A aortic dissection 5 years ago presented with a ruptured 10.7 cm × 7.3 cm aortic arch pseudoaneurysm involving the origins of the LCCA and the left subclavian artery. The patient underwent emergent endovascular aortic repair with placement of a stent graft in both IA and left carotid artery coursing parallel to the aortic arch endograft.

The endovenous laser treatment for patients with varicose veins.

OBJECTIVE: To evaluate the clinical effect of endovenous laser treatment (EVLT) for patients with varicose veins. METHODS: Our series included 117 patients who underwent EVLT combined with high ligation and stripping since the introduction of the technique in our institution. All EVLT procedures were performed with local skin cooling to prevent skin burns, as well as stripping after exsanguinations to prevent thrombotic phlebitis. RESULTS: A total of 146 limbs in 117 patients were ablated by EVLT. Bilateral EVLT was performed in 29 patients, with the remaining 88 patients undergoing unilateral EVLT. The mean age of the patients was 57 years ± 12 years (range: 21 years to 80 years), and 56 were male and 61 were female. Follow-up for all patients lasted three to six months. The most common complication was induration and swelling, which was observed in 64 patients, followed by paraesthesia in 27, and skin burns in 12. CONCLUSION: The treatment with endovenous laser treatment for patients with varicose veins is safe and effective.

Effect of Intravascular Ultrasound-assisted Thoracic Endovascular Aortic Repair for "Complicated" Type B Aortic Dissection.

BACKGROUND: Intravascular ultrasound (IVUS) examination can provide useful information during endovascular stent graft repair. However, its actual clinical utility in thoracic endovascular aortic repair (TEVAR) for type B aortic dissection (type B-AD) remains unclear, especially in complicated aortic dissection. We evaluated the effect of IVUS as a complementary tool during TEVAR. METHODS: From September 2011 to April 2012, we conducted a prospective cohort study of 47 consecutive patients with "complicated" type B-AD diagnosed. We divided the patients into two groups: IVUS-assisted TEVAR group and TEVAR using angiography alone group. The general procedure of TEVAR was performed. We evaluated the perioperative and follow-up events. Patient demographics, comorbidities, preoperative images, dissection morphology, details of operative strategy, intraoperative events, and postoperative course were recorded. RESULTS: A total of 47 patients receiving TEVAR were enrolled. Among them (females, 8.51%; mean age, 57.38 ± 13.02 years), 13 cases (27.66%) were selected in the IVUS-assisted TEVAR group, and 34 were selected in the TEVAR group. All patients were symptomatic. The average diameter values of IVUS measurements in the landing zone were greater than those estimated by computed tomography angiography (31.82 ± 4.21 mm vs. 30.64 ± 4.13 mm, P < 0.001). The technique success rate was 100%. Among the postoperative outcomes, statistical differences were only observed between the IVUS-assisted TEVAR group and TEVAR group for total operative time and the amount of contrast used (P = 0.013 and P < 0.001, respectively). The follow-up ranged from 15 to 36 months for the IVUS-assisted TEVAR group and from 10 to 35 months for the TEVAR group (P = 0.646). The primary endpoints were no statistical difference in the two groups. CONCLUSIONS: Intraoperative IVUS-assisted TEVAR is clinically feasible and safe. For the endovascular repair of "complicated" type B-AD, IVUS may be helpful for understanding dissection morphology and decrease the operative time and the amount of contrast used.

Application of the multi-planar reconstruction in endovascular treatment of type B aortic dissection.

BACKGROUND: Although Multi-planar reconstruction (MPR) has been considered a diagnostic imaging technique that observes more perspectives for diseases, few people have applied it surgically. In fact, MPR is also very useful to clinical operation, especially for patients with type B aortic dissection. It helps the surgeon to locate accurately with more information about aortic dissection, so that the safety and effectiveness of operation can be improved. This study examined the application of the MPR in intraoperative DSA imaging for precise positioning by accurately obtaining a cross-section, a spin angle of the coronal plane, and a tilt angle of the sagittal plane in treatment of type B aortic dissection. METHODS: The conventional and the MPR approaches were compared on positioning the aortic arch for surgery. A group of 40 patients (group A) and another group of 42 patients (group B) was sampled. About the comparison of baseline characteristics, a fourfold table χ(2) test was conducted on gender, and two independent samples t-test was applied to age between group A and group B. Spin as well as tilt angles for group A were obtained from the patients using both approaches, and their effectiveness was compared with pair t-tests; The MPR data guided stent-grafting in this group. Stent graft placement of group B was based on the conventional approach. Percentages of proximal distributed markers as well as incidences of complications were collected from both groups after stent graft placement. They were also compared with a fourfold table χ(2) test. RESULTS: Gender difference was not found between group A and group B (χ(2)0.80, P > 0.05), and age difference was not statistically significant (F = 2.55, homogeneity of variance, t = -1.46, P > 0.05). A significant difference was found between the conventional and the MPR approaches for spin angle (t = 9.17) as well as tilt angle (t = 2.07), P < 0.05. Percentage of proximal distributed markers (5.0%) of group A was significantly lower than that of group B (42.9%), χ(2) = 15.92, P < 0.05; and incidence of complications (5.0%) of group A was also significant lower than that of group B (21.4%), χ(2) = 4.76, P < 0.05. CONCLUSIONS: Application of the MPR facilitated intraoperative angle adaption and led to satisfactory DSA. It is feasible in endovascular treatment of type B aortic dissection, and can effectively and safely guide surgical operations.

[Endovascular repair for isolated iliac artery aneurysm].

OBJECTIVE: To evaluate the short and middle-term efficacies of endovascular repair for isolated iliac artery aneurysms (IIAAs). METHODS: Retrospective analyses were performed for the clinical and follow-up data of 27 patients undergoing endovascular repair at Department of Vascular Surgery, Affiliated Zhongshan Hospital, Fudan University from January 2008 to December 2012. For asymptomatic aneurysms, repair criterion was a diameter over 3 cm while under 3 cm for symptomatic aneurysms. RESULTS: There were 19 asymptomatic and 8 symptomatic cases. And 25 selective and 2 emergent operations were performed. The interventions included endovascular stent grafts (n = 17), coil embolization (n = 1), both stent grafts and coils (n = 7) and hybrid operations (n = 2). Technical success was achieved in all cases. No delayed healing or infection of inguinal access sites occurred. In-stent thrombosis could be observed in 2 cases. Buttock claudication was observed in one case. Sexual dysfunction occurred in three cases. Endoleaks were confirmed by intraoperative digital subtraction angiography in three cases. There was no occurrence of colorectal ischemia or postoperative aneurysmal rupture. Patients were followed up for a mean period of 33 ± 18 months. One patient died of recurrent renal cell carcinoma. CONCLUSION: Endovascular repair of isolated iliac artery aneurysms provides good short and middle-term patency. It may become a first-choice for treating isolated iliac artery aneurysms in the future.