Initial results of ultrasound screening for aneurysm of the abdominal aorta in Western Australia: relevance for endoluminal treatment of aneurysm disease

Background. Increased life expectancy in men during the last thirty years is largely due to the decrease in mortality from cardiovascular disease in the age group 29-69 yr. This change has resulted in a change in the disease profile of the population with conditions such as aneurysm of the abdominal aorta (AAA) becoming more prevalent. The advent of endoluminal treatment for AAA has encouraged prophylactic intervention and fuelled the argument to screen for the disease. The feasibility of inserting an endoluminal graft is dependent on the morphology and growth characteristics of the aneurysm. This study used data from a randomized controlled trial of ultrasound screening for AAA in men aged 65-83 yr in Western Australia for the purpose of determining the norms of the living anatomy in the pressurized infrarenal aorta. Aims. To examine (1) the diameters of the infra-renal aorta in aneurysmal and non-aneurysmal cases, (2) the implications for treatment modalities, with particular reference to endoluminal grafting, which is most dependent on normal and aneurysmal morphology, and (3) any evidence to support the notion that northern Europeans are predisposed to aneurysmal disease. Methods. Using ultrasound, a randomized control trial was established in Western Australia to assess the value of a screening program in males aged 65-83 yr, The infra-renal aorta was defined as aneurysmal if the maximum diameter was 30 mm or more. Aortic diameter was modelled both as a continuous tin mm) and as a binary outcome variable, for those men who had an infra-renal diameter of 30 mm or more. ANOVA and linear regression were used for modelling aortic diameter as a continuum, while chi-square analysis and logistic regression were used in comparing men with and without the diagnosis of AAA. Findings. By December 1998, of 19.583 men had been invited to undergo ultrasound screening for AAA, 12.203 accepted the invitation (corrected response fraction 70.8%). The prevalence of AAA increased with age from 4.8% at 65 yr to 10.8% at 80 yr (chi (2) = 77.9, df = 3, P<0.001). The median (IQR) diameter for the non-aneurysmal group was 21.4 mm (3.3 mm) and there was an increase (<chi>(2) = 76.0, df = 1, P<0.001) in the diameter of the infra-renal aorta with age. Since 27 mm is the 95th centile for the non-aneurysmal infra-renal aorta, a diameter of 30 mm or more is justified as defining an aneurysm. The risk of AAA was higher in men of Australian (OR = 1.0) and northern European origin (OR = 1.0, 95%CL: 0.9. 1.2) compared with those of Mediterranean origin (OR = 0.5, 99%CL: 0.4, 0.7). Conclusion. Although screening has not yet been shown to reduce mortality from AAA. these population-based data assist the understanding of aneurysmal disease and the further development and use of endoluminal grafts for this condition. (C) 2001 Published by Elsevier Science Ltd on behalf of The International Society for Cardiovascular Surgery.

Remission of heart failure through endoluminal repair of femoral arteriovenous fistula with the use of a covered stent

We report the case of a 21-year-old male with high-output heart failure due to a femoral arteriovenous fistula caused by a firearm wound. A new balloon expandable stent covered with polytetrafluorethylene was implanted in the artery to occlude the arteriovenous fistula. The fistula was immediately occluded and the artery remained patent. On the following day, the patient felt much better, with no symptoms of heart failure. Additional follow-up is required to assure the usefulness of this less invasive procedure in the treatment of arteriovenous fistulas.

Acute inflammatory reaction associated with endoluminal bypass grafts.

PURPOSE: Nonspecific inflammatory reactions characterized by local tenderness, fever, and flu-like discomfort have been seen in patients undergoing endoluminal graft placement in the abdominal aorta or the femoral arteries. We undertook a study to assess the clinical and laboratory parameters of this inflammation. METHODS: Ten patients with femoropopliteal artery (n = 9) or aortic (n = 1) lesions were treated with EndoPro System 1 stent-grafts made of nitinol alloy and covered with a polyester (Dacron) fabric. Eleven patients implanted with a bare nitinol stent served as the control group. RESULTS: In the stent-graft group, four patients showed clinical signs of acute inflammation manifested by fever and local tenderness. Three of these patients suffered thrombosis of the stent-grafts during the first month of follow-up. Plasma levels of interleukin-1 beta and interleukin-6 in all stent-graft patients were markedly increased 1 day after intervention (7.3 +/- 2.8 versus 90.2 +/- 34.1 pg/mL and 15.6 +/- 5.8 versus 175.5 +/- 66.3 pg/mL, respectively; p < 0.01). This was followed by an increase in fibrinogen (3.0 +/- 0.2 versus 5.0 +/- 0.2 g/L; p < 0.05) and C-reactive protein (14.6 +/- 3.3 versus 77.5 +/- 15.0 mg/L; p < 0.01) at 1 week. No direct correlation between the inflammatory markers and symptoms could be found. In vitro analysis showed that individual components of the stent-graft did not activate human neutrophils, whereas the intact stent-graft itself induced a marked neutrophil activation. CONCLUSIONS: The component of the self-expanding stent-graft responsible for the nonspecific inflammatory reaction was not identified in this study. It is likely that the stent-graft itself or some as yet unrecognized element of the device other than the Dacron fabric or metal alloy may be a potent in vivo inducer of cytokine reaction by neutrophils.

Trombose na endoprótese do aneurisma da aorta: avaliação por TC multidetector

OBJETIVO: Avaliar as características demográficas e de imagens da trombose endoluminal em uma série de pacientes submetidos a tratamento endovascular do aneurisma de aorta abdominal (TEAAA). MÉTODOS: Avaliamos as características de imagem que permitiram o diagnóstico da trombose endoluminal em uma série de 30 pacientes submetidos ao TEAAA, com seguimento de 5 a 29 meses, através de exames de tomografia computadorizada multidetectores (TCMD) de 64 canais. RESULTADOS: Foram diagnosticados dez casos de trombose luminal (33,3%), sendo que em três pacientes a trombose foi total de um ramo ilíaco. CONCLUSÃO: A TCMD permitiu o diagnóstico de diferentes tipos de trombose endoluminal em pacientes submetidos ao TEAAA. O uso desta modalidade diagnóstica minimamente invasiva deverá ser encorajado na prática clínica.

Mock circulatory system for the evaluation of left ventricular assist devices, endoluminal prostheses, and vascular diseases

A new digital computer mock circulatory system has been developed in order to replicate the physiologic and pathophysiologic characteristics of the human cardiovascular system. The computer performs the acquisition of pressure, flow, and temperature in an open loop system. A computer program has been developed in Labview programing environment to evaluate all these physical parameters. The acquisition system was composed of pressure, flow, and temperature sensors and also signal conditioning modules. In this study, some results of flow, cardiac frequencies, pressures, and temperature were evaluated according to physiologic ventricular states. The results were compared with literature data. In further works, performance investigations will be conducted on a ventricular assist device and endoprosthesis. Also, this device should allow for evaluation of several kinds of vascular diseases.

Twelve-month Outcomes After Coronary Stenting With the Genous (TM) Bio-Engineered R Stent (TM) in Diabetic Patients from the e-HEALING Registry

Objectives: We compared 12-month outcomes, regarding ischemic events, repeat intervention, and ST, between diabetic and nondiabetic patients treated with the Genous (TM) EPC capturing R stent (TM) during routine nonurgent percutaneous coronary intervention (PCI) using data from the multicenter, prospective worldwide e-HEALING registry. Background: Diabetic patients have an increased risk for restenosis and stent thrombosis (ST). Methods: In the 4,996 patient e-HEALING registry, 273 were insulin requiring diabetics (IRD), 963 were non-IRD (NIRD), and 3,703 were nondiabetics. The 12-month primary outcome was target vessel failure (TVF), defined as target vessel-related cardiac death or myocardial infarction (MI) and target vessel revascularization. Secondary outcomes were the composite of cardiac death, MI or target lesion revascularization (TLR), and individual outcomes including ST. Cumulative event rates were estimated with the Kaplan-Meier method and compared with a log-rank test. Results: TVF rates were respectively 13.4% in IRD, 9.0% in NIRD, and 7.9% in nondiabetics (P < 0.01). This was mainly driven by a higher mortality hazard in IRD (P < 0.001) and NIRD (P = 0.07), compared with nondiabetics. TLR rates were comparable in NIRD and nondiabetics, but significantly higher in IRD (P = 0.04). No difference was observed in ST. Conclusion: The 1-year results of the Genous stent in a real-world population of diabetics show higher TVF rates in diabetics compared with nondiabetics, mainly driven by a higher mortality hazard. IRD is associated with a significant higher TLR hazard. Definite or probable ST in all diabetic patients was comparable with nondiabetics. (J Interven Cardiol 2011;24:285-294)

Clinical results after coronary stenting with the Genous (TM) Bio-engineered R stent (TM): 12-month outcomes of the e-HEALING (Healthy Endothelial Accelerated Lining Inhibits Neointimal Growth) worldwide registry

Aims: e-HEALING is a worldwide, internet-based registry designed to capture post marketing clinical data on the use of the Genous (TM) EPC capturing R stent (TM). Rapid restoration of a healthy endothelial layer after stent placement by capturing circulating endothelial progenitor cells may reduce both stent thrombosis (ST) and in-stent-restenosis. Methods and results: We planned a 5,000 patient registry with >= 1 lesion suitable for stenting. The 12-month primary outcome was target vessel failure (TVF), defined as target vessel-related cardiac death or myocardial infarction (MI) and target vessel revascularisation. Secondary outcomes were the composite of cardiac death, MI or target lesion revascularisation (TLR), and individual outcomes including ST. A total of 4,939 patients received >= 1 Genous stent between 2005 and 2007. Baseline characteristics showed a median age of 63 years, 79% males, 25% diabetics, and 37% with prior MI. A total of 49% of lesions treated were ACC/AHA type B2 or C; 1.1 stents per lesion were used. At 12 months, TVF occurred in 8.4% and the composite of cardiac death, MI or TLR in 7.9%. Twelve-month TLR and ST were 5.7% and 1.1%, respectively. Conclusions: Coronary stenting with the Genous results in good clinical outcomes, and low incidences of repeat revascularisation and ST.

A quantitative coronary angiography-matched comparison between a prospective randomised multicentre cutting balloon angioplasty and bare metal stent trial (REDUCE III) and the Rapamycin-Eluting Stent Evaluation At Rotterdam Cardiology Hospital (RESEARCH) study

Aims: There remains significant concern about the long-term safety of drug-eluting stents (DES). However, bare metal stents (BMS) have been used safely for over two decades. There is therefore a pressing need to explore alternative strategies for reducing restenosis with BMS. This study was designed to examine whether IVUS-guided cutting balloon angioplasty (CBA) with BMS could convey similar restenosis rates to DES. Methods and results: In the randomised REstenosis reDUction by Cutting balloon angioplasty Evaluation (REDUCE III) study, 521 patients were divided into four groups based on device and IVUS use before BMS (IVUS-CBA-BMS: 137 patients; Angio-CBA-BMS: 123; IVUS-BA-BMS: 142; and Angio-BA-BMS: 119). At follow-up, the IVUS-CBA-BMS group had a significantly lower restenosis rate (6.6%) than the other groups (p=0.016). We performed a quantitative coronary angiography (QCA) based matched comparison between an IVUS-guided CBA-BMS strategy (REDUCE III) and a DES strategy (Rapamycin-Eluting-Stent Evaluation At Rotterdam Cardiology. Hospital, the RESEARCH study). We matched the presence of diabetes, vessel size, and lesion severity by QCA. Restenosis (>50% diameter stenosis at follow-up) and target vessel revascularisation (TVR) were examined. QCA-matched comparison resulted in 120-paired lesions. While acute gain was significantly greater in IVUS-CBA-BMS than DES (1.65 +/- 0.41 mm vs. 1.28 +/- 0.57 mm, p=0.001), late loss was significantly less with DES than with IVUS-CBA-BMS (0.03 +/- 0.42 mm vs. 0.80 +/- 0.47 mm, p=0.001). However, no difference was found in restenosis rates (IVUS-CBA-BMS: 6.6% vs. DES: 5.0%, p=0.582) and TVR (6.6% and 6.6%, respectively). Conclusions: An IVUS-guided CBA-BMS strategy yielded restenosis rates similar to those achieved by DES and provided an effective alternative to the use of DES.

Angioplasty and Stent Placement in Symptomatic Internal Carotid Occlusion

PURPOSE: To report a series of patients with symptomatic internal carotid artery (ICA) occlusion treated with angioplasty and stents. MATERIALS AND METHODS: From a consecutive series of 50 patients experiencing neurologic ischemic symptoms and shown by conventional ultrasonography (US) to have a total ICA occlusion, 16 patients (ages 45-79 years; mean, 63 y; 10 men) were selected between August 2006 to September 2008 to be treated with angioplasty based on discovery of an open ICA distal to the occlusion through contrast-enhanced echo Doppler imaging and/or multislice contrast computed tomography (CT). Angioplasty and stent placement were performed under cerebral protection. Follow-up duplex imaging was performed at 14 days and 3 months and every 6 months thereafter and CT follow-up was performed at 2-9 months; the mean follow-up period was 9.9 months. RESULTS: Lesion crossing and stent placement was successful in 13 of 16 patients. There were no deaths, conversions, cardiac complications, or major strokes. One patient had a transient mild hemiparesis in the upper limb, with total recovery in 3 months. At follow-up, all 13 patients with a good initial result remained with patent arterial lumens and resolution of neurologic ischemic symptoms. After 2-9 months, ICAs with a ""string sign"" had calibers close or equal to those of normal arteries. CONCLUSIONS: Angioplasty with stent placement is an effective treatment with a low morbidity rate for selected patients who continue to experience neurologic ischemic symptoms despite US findings of total occlusion of the ICA.

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. J Endovasc Ther. 2011; 18: 576-584

Nitinol biliary stent versus surgery for palliation of distal malignant biliary obstruction

Background Curative resection of pancreatic and biliary malignancies is rare. Most tumors are inoperable at presentation, and palliation of jaundice often is the goal. Biliary decompression can be achieved by surgical diversion or endoscopic biliary stents. This study aimed to compare clinical outcomes between surgical bypass and endoscopic uncovered nitinol stents in the palliation of patients with malignant distal common bile duct obstruction. Methods A multicenter, retrospective, cohort study investigated 86 patients with inoperable malignant distal common bile duct strictures at tertiary referral centers in Medellin, Colombia. These patients had undergone surgery (group 1) or placement of an uncovered 30-Fr self-expandable nitinol stent produced locally in Medellin, Colombia (group 2). The main outcome measurements included cumulative biliary patency, hospital stay, and patient survival. Results The study enrolled 86 patients (mean age, 66 years; range, 43-78 years) including 40 patients in group 1 and 46 patients in group 2. Both groups were similar in terms of age, gender, liver metastasis, and diagnosis. Technical success was achieved for 38 patients in group 1 (95%) and 43 patients in group 2 (93%). Functional biliary decompression was obtained in for 35 of the surgical patients (88%) and 42 of the stented patients (91%). Group 2 had lower rates for procedure-related mortality (2 vs. 7.5%; p = 0.01), a lower frequency of early complications (8.7 vs. 45%; p = 0.02), and a shorter hospital stay (median, 6 vs. 12 days; p = 0.01). Recurrent jaundice occurred for three patients in group 1 (7.5%) and eight patients in group 2 (17.3%) (p = 0.198). Late gastric outlet obstruction occurred for 12.5% of the patients in group 1 and 13% of the patients in group 2 (p = 0.73). Despite the early benefits of stenting, no significant difference in the median overall survival between the two groups was found (group 1, 163 days; group 2, 178 days; p = 0.11). The limitations of this study included the small number of patients and the retrospective design. Conclusions Endoscopic stenting and surgery are effective palliation. The former is associated with fewer early complications and the latter with fewer late complications. Patients who do not qualify for curative resection may be better managed by stent placement. Surgery should be reserved for patients more likely to survive longer.

Changes in Perfusion-Weighted Magnetic Resonance Imaging after Carotid Angioplasty with Stent

Carotid artery stenosis due to arteriosclerosis increases the risk of cerebral ischemia via embolic phenomena or reduced blood flow. The changes in cerebral perfusion that may occur after treatment are not clearly understood. This study evaluated the changes in cerebral microcirculation following carotid angioplasty with stenting (CAS) under cerebral protection with filters using ultrafast gradient echo (GRE) perfusion weighted imaging (PWI) with magnetic resonance imaging (MRI). Prospectively, 21 cervical carotid stenosis patients, mean age 69.95 years, underwent MRI 12 h before and 72 h after CAS. PWI parameters were collected for statistical analysis: cerebral blood volume (CB V), mean transit time (MTT) and time to peak (TTP). Statistical analysis was applied to absolute parameters and to values normalized against those from the contralateral parenchyma. The main finding of this study was improved hemodynamics for the normalized data after CAS, shown by reduced MTT (p<0.001) and TTP (p=0.019) in the territory fed by the middle cerebral artery ipsilateral to the CAS. Absolute data showed increased blood volume in the cerebral hemispheres after CAS, which was more accentuated on the stent side (p=0.016) than the contralateral side (p=0.029). Early improvements in cerebral perfusion, mainly seen in the normalized data, were clearly demonstrated in the timing parameters - TTP & MTT - after CAS.

A randomized trial of 5 versus 7 French guiding catheters for transfemoral percutaneous coronary stent implantation

Comparative studies between 5 French guiding catheter and others of larger size using the transfemoral approach to coronary stenting have not been described. Coronary stent implantation was performed in 90 patients in a randomized trial. The primary end-point was to compare the incidence of successful uncomplicated stent implantation per lesion with the 5F and 7F guiding catheters. Patients were excluded for excessive vessel tortuosity or anticipated need for equipment not fitting through a 5 catheter. Baseline characteristics and the use of direct stenting did not differ between the two groups. The primary success rate was 97.8% per patient in both groups and 98% per lesion in the 5 French and 97.9% in the 7 French. Guiding catheter change was necessary in 1 patient in each group to successfully complete the procedure in both groups. The amount of contrast used was 63 +/- 27.3 mL in the 5 French and 76 +/- 25 mL in the 7 French groups (P < 0.05). Vascular complications and blood transfusions occurred somewhat more frequently in the 7 French group (P = 0.058). The manual compression time after sheath removal was 5.1 +/- 2.0 min and 8.0 +/- 4.3 min, respectively, in the 5 and 7 French groups (P < 0.01). In conclusion, the 5 French guiding catheters showed a similar success rate with coronary stenting when compared to the 7 French, but the amount of contrast used and manual compression time after sheath removal, as well as the rate of vascular and bleeding complications, were reduced in the 5 French group.

A modified approach for vestibuloplasty in severely resorbed mandible using an implant-retained postoperative stent: a case report

Background. Severely resorbed mandibles often present a short band of keratinized tissue associated with a shallow vestibule. As a result, prominent muscle insertions are present, especially in the mental region of the mandible. This case report describes the deepening of the vestibular sulcus in an atrophic mandible by combining free gingival grafts harvested from the palate and a postoperative acrylic resin stent screwed on osseointegrated implants placed at the anterior region of the mandible. Study design. During the second-stage surgery, a split-thickness labial flap was reflected and apically sutured onto the periosteum. Two free gingival grafts were obtained and then sutured at this recipient site. A previously custom-made acrylic stent was then screwed onto the most distally positioned implants. To document the procedure`s stability over time, a metal ball was placed in the most apical part of the vestibule and standardized cephalometric radiographs were taken before and 6 months after the procedure. Linear measurements of vestibular depths over the observation time were realized using specific software for radiographic analysis. Results. The proposed technique augmented the band of attached masticatory mucosa, deepened the vestibule and prevented the muscle reinsertion. The difference between the 2 measurements of vestibular depths was 9.39 mm (initial 20.88 mm, final 11.49 mm) after a 6-month postoperative period. Conclusion. The technique, in combination with palatal mucosal graft and use of a postoperative stent, decreased the pull of mentalis muscle and provided a peri-implantally stable soft tissue around implants. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2008; 106: e7-e14)

Mechanical properties of stent-graft materials

An aneurysm is a localized blood-filled dilatation of an artery whose consequences can be deadly. One of its current treatments is endovascular aneurysm repair, a minimally invasive procedure in which an endoprosthesis, called a stent-graft, is placed transluminally to prevent wall rupture. Early stent-grafts were custom designed for the patient through the assembling of off-the-shelf components by the operating surgeon. However, nowadays, stent-grafts have become a commercial product. The existing endoprostheses differ in several aspects, such as shape design and materials, but they have in common a metallic scaffold with a polymeric covering membrane. This article aims to gather relevant information for those who wish to understand the principles of stent-grafts and even to develop new devices. Hence, a stent-graft classification based on different characteristics is presented and the desired features for an ideal device are pointed out. Additionally, the materials currently in use to fabricate this type of endoprosthesis are reviewed and new materials are suggested.