Prevalence of rare visceral aneurysms on 92,833 CAT scans (2005-2021).

Background: Studies on the prevalence of rare visceral aneurysms are still scarce and the few studies that have focused on these aneurysms present prevalence rates in groups of patients with visceral aneurysms, but little is known about their prevalence in the general population. Objectives: To assess the prevalence of rare visceral aneurysms on CAT scans performed for diagnosis and follow-up of patients with other vascular pathologies. Methods: This cross-sectional study began by accessing all reports from CAT scans performed between January 2005 and July 2021 at a private hospital of excellence located in the city of São Paulo. A software program for pre-indexed reports was used to search the Radiological Information System (RIS) database to identify reports of patients with intra-abdominal aneurysms. Results: CAT scan reports from 92,883 patients were accessed. Of these, 2,597 (2.795%) showed intra-abdominal aneurysms, 937 (1.063%) of which were visceral, including 158 (0.171%) rare visceral aneurysms, which were more frequent among male patients and in the following segments: celiac trunk (0.098%), superior mesenteric (0.033%), left gastric (0.010%), pancreatic-duodenal (0.009%), and gastroduodenal arteries (0.005%) and the pancreatic arch (0.004%). Lower prevalence was found in other segments. Additional findings revealed concomitance of rare visceral aneurysms with other intra-abdominal aneurysms ranging from 11.11% to 66.67%. Conclusions: The prevalence of rare visceral aneurysms in a large population undergoing CAT scan was 0.171%, with greater involvement in male patients.

Percutaneous endovascular delivery of calcium chloride to the intact porcine carotid artery: A novel animal model of arterial calcification.

OBJECTIVE: The present study evaluated the effect of endovascular administration of calcium chloride to the carotid artery of swines, to create a model of arterial calcification. METHODS: Fifteen Large White pigs were used for the study. Via endovascular treatment, carotid arteries were exposed during 9 min to either calcium chloride (experimental artery) or saline (control artery) with the use of the TAPAS catheter. Intravascular ultrasound (IVUS) imaging was obtained at baseline, postprocedure and at 30 days. Optical coherence tomography (OCT) imaging was obtained in vitro after carotids were harvested. Longitudinally cut parallel arterial segments were placed in a system of delicate clamps and underwent uniaxial strain test. All arteries underwent histopathological examination. RESULTS: Calcium chloride treated segments showed extensive circumferential parietal calcification evident on both IVUS and OCT. Reduction in minimal lumen area on IVUS was evident in experimental arteries both at 24 hr and 30 days postprocedure. Histopathologic assessment (Von Kossa stain) confirmed medial calcification with mild intimal thickening. Biomechanical testing showed treated segments to have smaller breaking strength and less elastic deformation than controls. CONCLUSION: We developed a nonexpensive, reproducible model of early carotid medial calcification in pigs. Our model has the potential to help the development of research to unravel mechanisms underlying arterial calcification, the use of current or new devices to treat calcified lesions as well as to serve as an option for training interventionalists on the use of such devices.

Duplex scan and histologic assessment of acute renal injury in a kidney-kidney crosstalk swine experimental model.

OBJECTIVE: The objective of this study was to identify the effect of two left renal vasculature occlusion strategies on the duplex ultrasound-assessed rheology and histology of the contralateral kidney. METHODS: Pigs were randomly assigned to one of two groups: left renal artery-only clamping (A group, n = 8) or left renal artery and vein clamping (AV group, n = 9). Bilateral renal parenchymal biopsy specimens were taken every 10 minutes for 90 minutes. Duplex ultrasound resistive index (RI) and pulsatility index (PI) were measured. Mixed models with normal distribution and first-order autoregressive correlation structure and generalized estimating equation models were used. Results are presented as adjusted means with standard errors, estimated proportions with standard errors, and line plots with 95% confidence intervals. RESULTS: RI and PI increased in the nonischemic kidney. In A group animals, RI values increased significantly (P < .01) after 30 minutes of ischemia and PI increased significantly (P < .04) from 30 to 60 minutes of ischemia. The number of histologic abnormalities was higher in A group than in AV group biopsy specimens. The percentage of lesions increased significantly after 10 minutes in A group nonischemic kidneys (P < .02) and between 50 and 80 minutes in AV group nonischemic kidneys (P < .01). CONCLUSIONS: Nonischemic kidneys were acutely affected by contralateral ischemia. Their function was more adversely affected by unilateral renal artery occlusion with preserved renal vein patency (A group).

Flow-diverting Stent in the Treatment of Cervical Carotid Dissection and Pseudoaneurysm: Review of Literature and Case Report.

BACKGROUND: The endovascular technique has been recommended over the past few years to extracranial carotid dissection and pseudoaneurysm with promising results, especially after medical therapy failure. Flow-diverting stents are an alternative for complex cases. These stents have proven to be effective treatment devices for intracranial aneurysms. METHODS: The reference list of Pham's systematic review, published in 2011, and Seward's literature review, published in 2015, was considered, as well as all new articles with eligible features. Search was conducted on specific databases: MEDLINE and Literatura Latino-Americana e do Caribe em Ciências da Saúde. RESULTS: For carotid dissection and pseudoaneurysm, our review yielded 3 published articles including 12 patients. The technical success rate of flow-diverting stent was 100% with no procedural complication described. Mean clinical follow-up was 27.2 months (range 5-48), and in 5 months' angiographic follow-up, all lesions had healed. No new neurological events were reported during the clinical follow-up. CONCLUSIONS: Flow diverter stent use on intracranial and peripheral vascular surgery demonstrates satisfactory initial results, but it is still under investigation. There are very few cases treated till now and the initial results with flow-diverting stents to cervical carotid dissection are promising. In well-selected cases, where simple embolization or conventional stent is not appropriate, this technic may be considered.

The similarities and differences among patients with abdominal aortic aneurysms referred to a tertiary hospital and found at necropsy.

OBJECTIVE: To analyze the characteristics of patients with abdominal aortic aneurysms referred to a tertiary center and to compare with individuals with abdominal aortic aneurysm found at necropsy. METHODS: We have retrospectively analyzed the medical records of 556 patients with abdominal aortic aneurysm and 102 cases abdominal aortic aneurysm found at necropsy. RESULTS: At univariated analysis, hypertension, tobacco use and maximum diameter were significant risk factors for symptomatic aneurysm, while diabetes tended to be a protective factor for rupture. By logistic regression analysis, the largest transverse diameter was the only one significantly associated with abdominal aortic aneurysm rupture (p < .0001, odds ratio 1.7, 95% confidence interval 1.481-1.951). Intact abdominal aortic aneurysm found at necropsy showed similarities with outpatients in relation to abdominal aortic aneurysm diameter and risk factors. CONCLUSION: Intact abdominal aortic aneurysm at necropsy and at outpatients setting showed similarities that confirmed that abdominal aortic aneurysm repair is less offered to women, and they died more frequently with intact abdominal aortic aneurysm from other causes.

Endovascular model of abdominal aortic aneurysm induction in swine.

Abdominal aortic aneurysms are among the main causes of death. The high morbidity and mortality associated with aneurysm rupture and repair represents a challenge for surgeons and high risk for patients. Although experimental models are useful to understand, train, and develop new treatment and diagnostic methods for this pathology, animal models developed to date are far from ideal. Animals are either too small and do not represent the pathology of humans, or the procedures employ laparotomy, or the aortic behavior does not resemble that of a true aneurysm. We developed a novel, less invasive and effective method to induce true aortic aneurysms in Large White pigs. Animals were submitted to an endovascular chemical induction using either calcium chloride (25%) or swine pancreatic elastase. Controls were exposed to saline solution. All animals were operated on using the same surgical technique under general anesthesia. They were followed weekly with ultrasound examinations and at 4 weeks the aorta was harvested. Although elastase induced only arterial dilation, imaging, histological, and biomechanical studies of the aorta revealed the formation of true aneurysms in animals exposed to calcium chloride. Aneurysms in the latter group had biomechanical failure properties similar to those of human aneurysms. These findings indicate that the endovascular approach is viable and does not cause retroperitoneal fibrosis.

Histologic analysis of stent graft oversizing in the thoracic aorta.

OBJECTIVE: To elucidate the histologic changes after stent graft oversizing in nonatherosclerotic aortas using an experimental porcine model. We previously reported that the diameter and angulation of the aorta in this model are similar to those in young individuals who undergo stent graft repair for blunt aortic injuries. The lack of commercially available stent grafts specific for repairing blunt aortic injuries, particularly for small and angulated aortas, may be related to the high rate of endograft complications in this population. METHODS: Twenty-five pigs were randomized into one control group (without stent graft implantation) and four oversized groups (A: 10%-19%, B: 20%-29%, C: 30%-39%, and D: >40%). Three circumferential fragments were collected from the aorta for histologic and immunohistochemical studies. Morphometric analyzes were performed using an inflow system and image analysis software (Quantimet 500; Leica Cambridge Ltd, Cambridge, UK). RESULTS: Collagen expression in the aortic wall was not significantly different among the five groups (P = .5604). There were significantly fewer muscle fibers in the aortic wall in the oversized groups compared with the control group (P = .000198). The proportion of elastic fibers in the aortic wall was significantly smaller in the oversized groups compared with the control group (P = .0000001). Immunohistochemical analysis showed that α-actin expression in the aortic wall was significantly decreased in the oversized groups compared with the control group (P = .002031). There were no significant differences in either the number of muscle fibers or α-actin expression among the four oversized groups. CONCLUSIONS: Histologic and immunohistochemical studies confirmed the structural disarrangement of the aortic wall after insertion of an endoprosthesis, including reduced number of muscle and elastic fibers.

Endovascular repair of a traumatic arteriovenous fistula involving the iliac bifurcation using an iliac branch device.

Endovascular techniques have shown to be useful in the management of vascular injuries because they transform a complex and potentially dangerous procedure into a safe one. We present the case of a 39-year-old man with congestive heart failure and abdominal bruit 11 years after an abdominal gunshot wound. Imaging studies revealed an arteriovenous fistula involving the left iliac artery bifurcation, and an iliac branch device was used to treat it. Symptoms resolved, and follow-up imaging showed patency of the graft and closure of the arteriovenous communication. To our knowledge, this is the first report of a nonaneurysmal disease treated with this device.

Impact of stent-graft oversizing on the thoracic aorta: experimental study in a porcine model.

PURPOSE: To analyze in an experimental animal model the effect of 4 different levels of stents-graft oversizing on non-atherosclerotic aortas such as those found in young individuals who undergo stent-graft repair for traumatic aortic injuries. METHODS: The diameter of the porcine thoracic aorta is similar to the aorta of young adults (18-20 mm), so 25 pigs were randomized into 5 groups: 1 control (without stent-graft) and 4 oversizing groups (A: 10%-19%, B: 20%-29%, C: 30%-39%, and D: >40%). Two types of biomechanical tests were performed on all aortas 4 weeks after endoprosthesis deployment. RESULTS: The results of the detachment test, which analyzed the strength necessary to remove the stent-graft from the aorta, were similar in the 4 groups (A: 42 N, B: 41 N, C: 46 N, and D: 46 N). However, 2 aortas ruptured during the tests (groups C and D). The second test was performed in 3 aortic segments. Maximum shear strength, maximum stress, and maximum tension supported by the aortic wall had a negative and linear correlation with oversizing. There were significant differences in all 4 groups when compared with the control group. Strain, which reflects the elastic properties of the aortic wall, was very similar in all 4 groups, but a great difference was found when compared with the control group (p<0.0001). CONCLUSION: The study showed an important subacute change in the biomechanical properties of the aortic wall after implantation of an oversized endoprosthesis. This weakness of the aortic wall was confirmed by 2 ruptures during the detachment test. These results partially explain the interaction of stent-grafts with non-atherosclerotic thoracic aortas and may serve as a basis for further studies and the development of specific material to be used in vascular trauma and young patients.

Multilayer stents affect the final diameter of aortic aneurysms and maintain renal artery patency for a short time in a swine experimental model.

OBJECTIVES: We sought to analyze the hemodynamic effects of the multilayer flow-modulated stent (MFMS) in Thoracoabdominal aortic aneurysms (TAAAs). METHODS: The hemodynamic effects of MFMS were analyzed in aortic thoracoabdominal aneurysms in experimental swine models. We randomly assigned 18 pigs to the stent or control groups and underwent the creation of an artificial bovine pericardium transrenal aneurysm. In the stent group, an MFMS (Cardiatis, Isnes, Belgium) was immediately implanted. After 4 weeks, we evaluated aneurysm sac thrombosis and renal branch patency by angiography, duplex scan, and morphological analysis. RESULTS: All the renal arteries remained patent after re-evaluation in both groups. Aneurysmal sac thrombosis was absent in the control group, whereas in the stent group it was present in 66.7% of aneurysmal sacs (p=0.061).The mean final aneurysm sac diameter was significantly lower in the stent group (mean estimated reduction, 6.90 mm; p=0.021). The proximal neck diameter decreased significantly in the stent group (mean difference, 2.51 mm; p=0.022) and grew significantly in the control group (mean difference, 3.02 mm; p=0.007). The distal neck diameter increased significantly in the control group (mean difference, 3.24 mm; p=0.017). There were no significant findings regarding distal neck measurements in the stent group. CONCLUSION: The MFMSs remained patent and did not obstruct the renal arteries within 4 weeks. In the stent group, the device was also associated with a significant decrease in aneurysmal sac diameter and a large proportion (albeit non-significant) of aneurysmal sac thrombosis.

Improvement in parameters of quality of life and uterine volume reduction after uterine fibroid embolization.

OBJECTIVE: To evaluate improvement in quality of life, reduction of uterine volume, and the correlation between these two variables after uterine fibroid embolization. METHODS: Data on quality of life before and after uterine fibroid embolization were collected from 60 patients using the Uterine Fibroid Symptom - Quality of Life questionnaire. In 40 of these patients, uterine volume information on magnetic resonance imaging examinations performed before and after uterine fibroid embolization was collected, and compared using the nonparametric Wilcoxon test for paired data. Correlation between quality of life and uterine volume before and after procedure was measured using Spearman's correlation coefficient. RESULTS: There was significant improvement in quality of life after uterine fibroid embolization on Uterine Fibroid Symptom - Quality of Life questionnaire, in both subscales scores and the total score. There was a significant median reduction of -37.4% after uterine fibroid embolization, but no correlations between uterine volume and quality of life scores were found before or after embolization. CONCLUSION: Uterine embolization is an alternative to treat uterine fibroids, resulting in relief of symptoms and better quality of life. Although reduction in uterine volume plays an important role in the evaluation of therapeutic success, it does not necessarily have a definitive correlation with relief of symptoms.

Prospective randomized trial comparing radiofrequency ablation and complete saphenous vein stripping in patients with mild to moderate chronic venous disease with a 3-year follow-up.

OBJECTIVE: To compare the use of the radiofrequency thermoablation of the saphenous vein with the ligation technique, and complete removal of the saphenous vein, from the saphenofemoral junction to the ankle. METHODS: A total of 49 patients with chronic venous disease in the Comprehensive Classification System for Chronic Venous Disorders (CEAP) classes 2 to 4 for clinical signs, etiology, anatomic distribution and pathophysiology, were assessed at baseline, after 4 weeks, and after 1 year. The parameters assessed were complications, period of absence from activities, Venous Clinical Severity Score (VCSS) and quality of life scores according to Aberdeen Varicose Veins Questionnaire (AVVQ). They were re-examined 1 and 3 years after treatment to evaluate recurrence rates. RESULTS: The success rate per limb (p=0.540), VCSS (p=0.636), AVVQ (p=0.163), and clinical complications were similar in the two treatment groups. Nevertheless, the radiofrequency thermoablation group had significant shorter length of hospital stay (0.69±0.47) and absence from activities (8.62±4.53), p<000.1. CONCLUSION: Patients submitted to radiofrequency thermoablation had an occlusion rate, clinical recurrence and improvement in quality of life comparable to removal of the saphenous vein. However, these patients spent less time hospitalized and away from their daily activities during recovering.

Symptomatic duodenal perforation by inferior vena cava filter.

Objectives Duodenal perforation by an inferior vena cava filter is rare and life threatening. Our objective is to find out number of occurrences and compare diagnosis and treatments. Method The reference list of Malgor's review in 2012 was considered as well as all new articles with eligible features. Search was conducted on specific databases: MEDLINE, Web of Sciences, and Literatura Latino-Americana e do Caribe em Ciências da Saúde. Results Most of the patients presented with upper abdominal pain and the use of radiologic studies was crucial for diagnosis. The most common treatment was laparotomy with filter or strut removal plus duodenum repair. However, clinical conditions of patients must be considered and the endovascular technique with endograft deployment into inferior vena cava may be an alternative. Conclusion Duodenal perforation by an inferior vena cava filter is uncommon and in high-risk surgical patients endovascular repair must be considered.

Prevalência de aneurismas viscerais raros em 92.833 angiotomografias (2005-2021) / Prevalence of rare visceral aneurysms on 92,833 CAT scans (2005-2021)

Resumo Contexto Ainda são incomuns os estudos de prevalência de aneurismas viscerais raros, e os poucos estudos que focalizaram esses aneurismas observam taxas de prevalência em grupos de pacientes com aneurismas viscerais, mas pouco se conhece sobre a sua prevalência na população geral. Objetivos Avaliar a prevalência de aneurismas viscerais raros em angiotomografias realizadas para diagnóstico e seguimento de pacientes com diferentes patologias vasculares. Métodos Este estudo transversal partiu do acesso a todos os laudos de angiotomografias realizadas entre janeiro de 2005 e julho de 2021 em hospital privado de excelência situado na cidade de São Paulo. Foi utilizado um programa de mecanismo de busca de laudos pré-indexados, cuja base de dados é o Sistema de Informação Radiológica (RIS), para acesso aos laudos de pacientes com aneurismas intra-abdominais. Resultados Foram acessados laudos de angiotomografias de 92.883 pacientes, dos quais 2.597 (2,795%) apresentavam aneurismas intra-abdominais, sendo 937 (1,063%) viscerais, incluindo 158 (0,171%) aneurismas viscerais raros, mais frequente entre homens e nos seguintes segmentos: tronco celíaco (0,098%), artéria mesentérica superior (0,033%), artéria gástrica esquerda (0,010%), artéria pancreático-duodenal (0,009%), artéria gastroduodenal (0,005%) e arco pancreático (0,004%). Prevalências menores foram encontradas em outros diferentes segmentos. Achados adicionais revelaram taxa de concomitância de aneurismas viscerais raros com outros aneurismas intra-abdominais entre 11,11% e 66,67%. Conclusões A prevalência de aneurismas viscerais raros em ampla população submetida a angiotomografias foi de 0,171%, com maior comprometimento nos pacientes do sexo masculino.

Abstract Background Studies on the prevalence of rare visceral aneurysms are still scarce and the few studies that have focused on these aneurysms present prevalence rates in groups of patients with visceral aneurysms, but little is known about their prevalence in the general population. Objectives To assess the prevalence of rare visceral aneurysms on CAT scans performed for diagnosis and follow-up of patients with other vascular pathologies. Methods This cross-sectional study began by accessing all reports from CAT scans performed between January 2005 and July 2021 at a private hospital of excellence located in the city of São Paulo. A software program for pre-indexed reports was used to search the Radiological Information System (RIS) database to identify reports of patients with intra-abdominal aneurysms. Results CAT scan reports from 92,883 patients were accessed. Of these, 2,597 (2.795%) showed intra-abdominal aneurysms, 937 (1.063%) of which were visceral, including 158 (0.171%) rare visceral aneurysms, which were more frequent among male patients and in the following segments: celiac trunk (0.098%), superior mesenteric (0.033%), left gastric (0.010%), pancreatic-duodenal (0.009%), and gastroduodenal arteries (0.005%) and the pancreatic arch (0.004%). Lower prevalence was found in other segments. Additional findings revealed concomitance of rare visceral aneurysms with other intra-abdominal aneurysms ranging from 11.11% to 66.67%. Conclusions The prevalence of rare visceral aneurysms in a large population undergoing CAT scan was 0.171%, with greater involvement in male patients.

Late results of catheter-directed recombinant tissue plasminogen activator fibrinolytic therapy of iliofemoral deep venous thrombosis.

PURPOSE: To evaluate the efficacy of catheter-directed low-dose recombinant tissue-type plasminogen activator infusion in the treatment of iliofemoral deep venous thrombosis and prevention of post-thrombotic syndrome. METHOD: Eighteen patients (out of 260 evaluated) with acute iliofemoral deep venous thrombosis and no previous evidence of venous insufficiency were prospectively selected for thrombolytic therapy. Catheter-directed low-dose recombinant tissue-type plasminogen activator (1 mg/h) was infused into the thrombotic segments. RESULTS: Effective fibrinolysis was achieved in 14 of 18 cases, with correlation between effective fibrinolysis and major/complete resolution of acute signs and symptoms (P <.01). There were no episodes of major complications. Four patients presented with early rethrombosis (1 to 8 weeks). Individuals were followed for a period up to 131 weeks (average, 85.2). The incidence of clinical signs and symptoms of venous insufficiency and duplex-scan findings of valvular reflux was significantly lower in the patients in which lytic therapy succeeded and patency was kept, compared with patients experiencing acute therapeutic failure or rethrombosis (P <.01). CONCLUSIONS: Low-dose recombinant tissue-type plasminogen activator fibrinolytic therapy is safe and effective in the treatment of acute iliofemoral venous thrombosis. The late evolution as revealed clinically and by ultrasound was superior in patients for whom lytic therapy was effective.

Follow-up of the aneurysmal sac after exclusion and bypass of popliteal artery aneurysms.

UNLABELLED: Popliteal artery aneurysms are frequent and may lead to thromboembolic events and limb loss. PURPOSE: To evaluate clinical and ultrasonographic follow-up of patients who underwent exclusion of a popliteal artery aneurysm using the technique proposed by Edwards. METHODS: Data of all patients who underwent surgery to repair a popliteal artery aneurysm at Hospital das Clinicas, the São Paulo University Medical School between 1996 and 2004 were reviewed. Inclusion criteria were repair with aneurysm exclusion and bypass using the technique proposed by Edwards, as well as the existence of preoperative and postoperative measurements of the aneurysmal sac. RESULTS: Data of 16 patients who underwent 20 procedures for popliteal artery aneurysm exclusion and bypass were available to analysis. The preoperative diameter of the popliteal artery aneurysms ranged from 1.3 cm to 6.1 cm (mean = 3.1 cm). Patients underwent duplex ultrasound scanning 1 month to 7 years after surgical repair. Follow-up of the 20 cases revealed that 10 aneurysms exhibited decreased mean transverse diameters, ranging from 0.2 to 2.3 cm, while 7 had increased in diameter, ranging 0.3 to 3.3 cm, and 3 remained unchanged. Flow was observed only in 5 out of the 20 procedures, 3 of which (60%) had increased diameters. CONCLUSION: Although exclusion is a widely accepted procedure for the repair of popliteal artery aneurysms, data in the literature and the results of this study, which did not include cases of rupture or compression, suggest that strict follow-up of patients who undergo aneurysm exclusion is necessary.

Common Carotid Artery Occlusion: A Single-Center Experience in 40 Cases.

The incidence of common carotid artery occlusion (CCAO) is approximately 3% in patients who undergo angiography for symptomatic cerebrovascular disease; however, few studies have reported on management of this condition. The objective of this article was to analyze risk factors, therapeutic options, and clinical benefits of surgical treatment at a hospital in the city of São Paulo, Brazil. Data were collected from medical records of 40 patients with CCAO who were treated from June 2002 to October 2013. Results were analyzed retrospectively. Most of the patients were men (63.0%), who were significantly younger than women. Most of the participants had hypertension (90.0%), and more than half had a history of smoking (52.5%). The mean number of coexisting comorbidities/risk factors was 2.9 ± 1.0. Half of our sample had ipsilateral patent internal and external carotid artery, and 32.5% presented with an occluded internal carotid artery and a patent external artery. Patients with both an internal and an external occluded carotid artery (12.5%) were significantly older. Contralateral arteriosclerosis was observed in 65% of the patients, mainly represented by 50 to 90% stenosis. Most patients were symptomatic (67.5%), and hemiparesis was the most common symptom (55.0%) found. Most (77.5%) of the patients underwent the medical treatment; one out of three endovascular approaches failed. During the mean follow-up of 55 ± 43 months (range, 2-136 months), 17.5% of the patients died within 4 days after surgical repair and after along 123 months of clinical follow-up. Coexisting comorbidities/risk factors were significantly associated with fatal outcomes, such as acute myocardial infarction. This study provides scientific evidences on treatment and outcomes of CCAO.

Multilayer stents affect the final diameter of aortic aneurysms and maintain renal artery patency for a short time in a swine experimental model

OBJECTIVES: We sought to analyze the hemodynamic effects of the multilayer flow-modulated stent (MFMS) in Thoracoabdominal aortic aneurysms (TAAAs). METHODS: The hemodynamic effects of MFMS were analyzed in aortic thoracoabdominal aneurysms in experimental swine models. We randomly assigned 18 pigs to the stent or control groups and underwent the creation of an artificial bovine pericardium transrenal aneurysm. In the stent group, an MFMS (Cardiatis, Isnes, Belgium) was immediately implanted. After 4 weeks, we evaluated aneurysm sac thrombosis and renal branch patency by angiography, duplex scan, and morphological analysis. RESULTS: All the renal arteries remained patent after re-evaluation in both groups. Aneurysmal sac thrombosis was absent in the control group, whereas in the stent group it was present in 66.7% of aneurysmal sacs (p=0.061). The mean final aneurysm sac diameter was significantly lower in the stent group (mean estimated reduction, 6.90 mm; p=0.021). The proximal neck diameter decreased significantly in the stent group (mean difference, 2.51 mm; p=0.022) and grew significantly in the control group (mean difference, 3.02 mm; p=0.007). The distal neck diameter increased significantly in the control group (mean difference, 3.24 mm; p=0.017). There were no significant findings regarding distal neck measurements in the stent group. CONCLUSION: The MFMSs remained patent and did not obstruct the renal arteries within 4 weeks. In the stent group, the device was also associated with a significant decrease in aneurysmal sac diameter and a large proportion (albeit non-significant) of aneurysmal sac thrombosis.

Developing a new endograft for the treatment of juxtarenal aortic aneurysms: definition and experimentation.

OBJECTIVES: To analyze angiotomographic parameters of juxtarenal aneurysms to assess the applicability of an endograft model to patients and to create in vitro and in vivo models to assess the new endograft. METHODS: A total of 49 patients with juxtarenal aneurysms were submitted to angiotomographic evaluation, and parameters such as the aortic diameter, the length of the neck, and the angulations of the celiac trunk, superior mesenteric artery and renal arteries; the distances between them; and anatomic variations were analyzed. Based on these parameters, an endograft model was developed and tested in a newly created in vitro model of juxtarenal aneurysm. An experimental model of juxtarenal aneurysm was then established in six pigs weighing 50-60 kg to assess the new endograft model. RESULTS: The angiotomographic parameters of juxtarenal aneurysm measured in this study were similar to those reported in the literature and allowed the development of an endograft based on the hourglass concept, which was applicable to 85.8% of the patients. The in vitro model of juxtarenal aneurysm evidenced good radiopacity and functionality and permitted adjustments in the new device and technical improvements in the procedures for treating these aneurysms. In addition, the porcine model of juxtarenal aneurysm was successfully created in all six animals using a bovine pericardial patch, and use of the new endograft in three pilot procedures evidenced its feasibility. CONCLUSIONS: The Hourglass endograft was rendered applicable to treatment of the majority of patients with juxtarenal aneurysms simply by changing its diameter. Moreover, the new in vitro and in vivo models were shown to be effective for assessing both the presented endograft and experiments assessing the endovascular treatment of juxtarenal aneurysms.