Aortomonoiliac endografting after failed endovascular aneurysm repair: indications and long-term results.

OBJECTIVES: To present long-term results of endoleak/endograft migration treatment by aortomonoiliac (AMI) endografting after failed endovascular aneurysm repair (EVAR) of infrarenal abdominal aortic aneurysms. DESIGN: Post hoc analysis of a prospectively gathered database at a tertiary care university hospital. MATERIALS AND METHODS: From March 1995 to November 2010, 23 patients were identified who underwent modification into AMI configuration after failed elective EVAR. Major causes for modification were type I (with/without endograft migration) or type III endoleaks with aneurysm expansion. An average increase in aneurysm size of 1.6 cm (range: -1.5 to 10.5 cm) since initial aneurysm treatment was observed. Interventional outcomes and long-term results were recorded for analysis. RESULTS: Technical success rate of AMI endografting was 95.65% (n = 22). All except two endoleaks could be successfully sealed with this manoeuvre (94.44%). Median time to modification was 5.3 years (interquartile range Q1-Q3: 1.3-9.3 years). No intra-operative conversion to open surgery was necessary and mortality was 0%. Median follow-up was 44 months (interquartile range Q1-Q3: 17-69 months). CONCLUSIONS: Treatment of graft-related endoleaks/endograft migration by AMI endografting after failed EVAR represents a safe and feasible procedure. This approach broadens the minimal invasive opportunities of aneurysm treatment, and open surgical conversion may be avoided except in selected patients.

Elective abdominal aortic aneurysm repair: does the aneurysm diameter influence long-term survival?

OBJECTIVES: The aim of this study was to investigate whether initial abdominal aortic aneurysm (AAA) diameter influences long-term survival after elective repair. DESIGN: Retrospective analysis of database. MATERIAL AND METHODS: Between March 1995 and December 2006, a consecutive series of 895 patients underwent elective treatment of an AAA either by open surgical or endovascular repair. An AAA diameter of 5.5cm was chosen as threshold to distinguish between small and large aneurysms, according to the definition given by the UK small aneurysm trial. Patient characteristics and distribution of basic risk factors were assessed. Survival estimates (Kaplan-Meier) and Cox proportional hazards regression results are reported. RESULTS: Patients with small aneurysms were more likely to survive the first 6 years after AAA repair, even after adjustment for treatment modality and baseline risk factors. After adjustment for age and sex aneurysms with smaller diameter were related to a lower risk of death (p<0.0016). CONCLUSIONS: Patients with small aneurysms (< or =5.5cm) have an improved long-term survival than patients with larger aneurysms.

Endovascular versus open surgical AAA exclusion techniques the importance of individual patient selection criteria.

Abdominal aortic aneurysms (AAA) are managed by two different treatment options, i.e. open graft replacement (OGR) as open surgical technique or endovascular aneurysm repair (EVAR) as minimally invasive procedure, to avoid fatal rupture. The intention of this review was to show how by offering electively either OGR or EVAR - adjusted to the patient's individual risk profile--a benefit for the individual patient could be obtained and overall mortality rates of elective AAA repair could be significantly reduced. A comparative evaluation of both treatment regimes is offered, latest literature as well as own research is presented. Our own risk adjusted patient selection regime is described as well as its statistically significant impact on overall mortality rates in elective AAA exclusion. As conclusion, the benefit of offering both EVAR and OGR is the capability to select and recommend the optimal AAA management for the individual patient with respect to the individual risk profile. The result is a decrease in the overall mortality rate while simultaneously the number of treated patients increases. Furthermore EVAR offers a treatment option for otherwise incurable high risk patients.

Plaque imaging of the internal carotid artery - correlation of B-flow imaging with histopathology.

BACKGROUND AND PURPOSE: The noninvasive identification of plaque types prone to cause symptomatic disease is of great interest to improve the effectiveness of surgical or interventional management. The purpose of the present prospective pilot study was to evaluate the association between the results of imaging-the novel sonography technique B-flow imaging (BFI), B-mode, and color Doppler imaging (CDI)-and histopathologic examination in the characterization of internal carotid artery (ICA) plaques. METHODS: Twenty-eight consecutive patients with high-grade internal carotid artery stenosis scheduled for carotid endarterectomy were included. BFI, B-mode, and CDI images were used to classify the plaques applying the standardized scores of Beletsky et al and the American Heart Association (AHA), to calculate the gray-scale median (GSM) and to detect potential ulcerations; histopathologic examination results of explanted plaques served as the "gold standard." RESULTS: Based on the classification of Beletsky et al, BFI and histopathologic examination results agreed in 21 (75%, kappa = 0.61, P < .001) patients, and the corresponding results for B-mode were 19 (68%, kappa = 0.52, P < .001) patients, respectively. Corresponding results for the AHA classification revealed inferior agreements for BFI (19 patients/68%, kappa = 0.38, P = .003) and B-mode (17 patients/61%, kappa = 0.25, P = .045). The median GSM for BFI and B-mode correlated significantly (r = 0.95, P < .001). The sensitivity of BFI for the detection of ulcerated plaques was 100% and the specificity was 95.8%; corresponding values for CDI were 100% and 92.7%, respectively. CONCLUSION: BFI and the combination of B-mode and CDI exhibit comparable results in the assessment of ICA plaque components and plaque ulceration as well as in the determination of GSM levels.

Limb-salvage by femoro-distal bypass and free muscle flap transfer.

OBJECTIVES: To evaluate the feasibility and long-term outcome of distal arterial reconstruction combined with free muscle flap transfer for patients who would otherwise have undergone major amputation. METHODS: Between 1996 and 2001, 27 reconstructions using autologous vein were performed in 25 patients. Seventeen of these patients had diabetes mellitus. Gracilis, rectus abdominis and latissimus dorsi muscles were used as free flaps, covered with split-thickness skin grafts. RESULTS: Eighty-five percent of patients had a patent graft and viable muscle flap after 1-month. Mean follow-up was 51 months (4-72 months). At the time of follow-up 77% of reconstructions were patent and 70% of patients regained full functional capacity of their lower extremities. CONCLUSION: Limb-salvage by distal arterial reconstruction and free muscle flap transfer, is feasible with low mortality and morbidity and provides excellent long-term results with regard to graft patency and functional status.

Positive effect of treatment with synthetic steroid hormone tibolon on intimal hyperplasia and restenosis after experimental endothelial injury of rabbit carotid artery.

BACKGROUND: Arterial intimal hyperplasia and following restenosis may be inhibited by estrogens. We investigated the effect of a synthetic steroid hormone, Tibolon: (a) on intima hyperplasia and restenosis in vivo, and (b) on production of endothelial nitric oxide synthase (eNOS), vascular endothelial growth factor (VEGF), endothelial cell proliferation and apoptosis in vitro. METHODS: Influence of Tibolon treatment (0.1 mg/kg body weight, during 3 days before and 3 weeks after the operation as a drinking solution once daily) on neointimal formation (measured by morphometry) and arterial wall damage (by qualitative histology) were investigated in vivo using an animal model of balloon injury of carotid artery. In human umbilical vein endothelial cells (HUVEC) and human microvascular endothelial cells (HMEC-1), the effect of Tibolon (0.1 microg/ml) on eNOS and VEGF was assessed by ELISA. Cell proliferation was induced by VEGF(165) and measured by BrdU incorporation assay, cell apoptosis was detected colorimetrically measuring DNA fragmentation. RESULTS: Balloon injury resulted in neointima formation and prominent damage of the carotid artery wall. Treatment with Tibolon increased luminal area, decreased intimal area and intima to media ratio, and promoted better reparation of damaged vessel wall. In vitro, Tibolon treatment did not influence the expression of eNOS protein in HUVEC as well as cell proliferation rate but reduced apoptosis of endothelial cells by about 40%. Additionally, this treatment suppressed basal and IL-1beta-stimulated synthesis of VEGF in HMEC-1. CONCLUSIONS: Tibolon treatment suppressed neointimal formation and promoted better reparation of damaged vessel wall in carotid artery after balloon injury. This positive effect seems to be associated with improved endothelial cell survival resulting possibly in increased NO production. It might be also related to the decrease of VEGF generation.

Experimental comparison of four methods of end-to-side anastomosis with expanded polytetrafluoroethylene.

BACKGROUND: Four established techniques of distal end-to-side anastomosis (direct anastomosis, Linton patch, Taylor patch and Miller cuff) were compared to investigate the local distribution of anastomotic intimal hyperplasia. The study aimed to elucidate whether mechanical factors or flow alterations are mainly responsible for the improved patency rates reported for vein cuff interposition techniques in infrainguinal arterial reconstructions using prosthetic graft material. METHODS: Thirty-two expanded polytetrafluoroethylene (ePTFE) femoropopliteal bypass grafts were implanted in 16 sheep using the four anastomotic techniques. After 6 months the grafts were explanted and examined histologically. The local distribution of intimal hyperplasia was determined, particularly for areas of material transition and of high and low shear stress. RESULTS: The mean amount and distribution of intimal hyperplasia were similar for all anastomotic types. Intimal hyperplasia was greatest along all transitions between ePTFE and venous patches, and between ePTFE and recipient artery. It was lower along the transitions between venous patches and artery, and was lowest at the host artery floor. CONCLUSION: Vein interposition did not reduce anastomotic intimal hyperplasia and did not change the distribution patterns of hyperplasia, which were influenced mainly by mechanical factors. The effect of vein interposition is to move areas of maximum intimal hyperplasia away from the small recipient artery up to the more capacious graft-patch anastomosis.

The impact of endovascular stent grafting on reducing mortality rates after surgical treatment of abdominal aortic aneurysms.

OBJECTIVES: to investigate whether appropriate selection in patients with infrarenal abdominal aortic aneurysms (AAA) for transfemoral endovascular aneurysm management (TEAM) or open graft replacement (OGR) may decrease in-hospital mortality rates (MR). DESIGN: analysis of a clinical series over three periods in an university vascular center. Conclusions of the second period were drawn and prospectively applied in a third period and compared. METHODS: during the period 1989-1994 only OGR was available (n=170). In the interval 1995-2000 either OGR or TEAM were carried out (n=454). During the period 01/2001-07/2002 the conclusions concerning selection of treatment modality were drawn and prospectively applied in 132 consecutive patients. MR were recorded and possible significant differences were checked. RESULTS: during the first period MR was 6.5%. Overall MR decreased to 3.7% in the second interval. Overall MR of the last period was improved to 1.5% (p<0.05). No patient died after OGR (0% vs 6.5%, p<0.04). As all patients with significant individual risk profiles were treated by TEAM, MR slightly increased (2.9%), but the difference remained insignificant (2.4% in period 2). CONCLUSIONS: risk adjusted selection of treatment modality influences the results after OGR significantly, thereby reducing overall MR of elective AAA treatment.

Development of 'no-reflow' phenomenon in ischemia/reperfusion injury: failure of active vasomotility and not simply passive vasoconstriction.

BACKGROUND/AIM: Local blood flow failure (no-reflow phenomenon) during ischemia/reperfusion (I/R) injury may be mediated by interstitial edema formation (passive vasoconstriction) and/or microvascular spasm (active vasoconstriction). The development of the no-reflow phenomenon in the rabbit hind limb I/R model and the influence of treatment with L-arginine and/or antioxidative vitamins were investigated. METHODS: Untreated rabbits were compared with those treated with L-arginine (4 mg/kg/min) or antioxidative vitamins (0.4 ml/kg) alone or in combination during hind limb I/R (2.5/2 h). Interstitial edema formation and microvessel diameter alterations were measured morphometrically. Capillary blood perfusion was measured continuously with laser Doppler flowmetry. RESULTS: I/R injury was expressed by interstitial edema formation (interstitial space increase by 80%), microvascular constriction (microvessel cross-sectional area decrease by 30%), and development of no-reflow phenomenon (blood flow reduction by 60%). Treatment with antioxidative vitamins alone or L-arginine alone reduced interstitial edema by 22 and 31%, consequently, while combined L-arginine/antioxidative vitamin treatment showed a more pronounced edema reduction by 40%. Treatment with only antioxidative vitamins failed to influence the development of no-reflow, although interstitial edema formation was reduced. L-Arginine treatment alone or in combination with antioxidative vitamins prevented microvascular constriction and preserved blood flow after reperfusion without development of no-reflow despite still apparent interstitial edema. CONCLUSIONS: Affections of active vasomotility and not merely passive changes of external pressure (i.e., interstitial edema formation) should be considered important in the development of microvascular constriction during 'no-reflow' phenomenon.

Delivery of high dose VEGF plasmid using fibrin carrier does not influence its angiogenic potency.

Delivery of DNA mixed with a degradable matrix carrier was supposed to improve transgene expression. Using a rabbit hind-limb ischemia model, we tested the angiogenic potency of plasmid encoding human vascular endothelial growth factor (pSG5-VEGF165) entrapped in fibrin sealant. Animals were injected intramuscularly with 500 microg of pSG5-VEGF165 or control plasmid, dissolved in saline (PBS) or fibrin glue. After 14 days, presence of delivered constructs and expression of transgene was confirmed in injected muscles of all animals. There were no significant differences in the levels of human VEGF mRNA and protein between VEGF-PBS and VEGF-fibrin groups (Mann-Whitney test). Accordingly, pSG5-VEGF165 regardless of the way of delivery, induced similar increases in capillary density within treated muscles (ANOVA). Control plasmid did not show any effects. In conclusion, injection of pSG5-VEGF165 into ischemic adductor muscle leads to synthesis of human VEGF and increases the number of capillaries. Fibrin carrier does not influence its angiogenic potential.

Collagen versus gelatin-coated Dacron versus stretch polytetrafluoroethylene in abdominal aortic bifurcation graft surgery: results of a seven-year prospective, randomized multicenter trial.

BACKGROUND: A prospective randomized multicenter trial was performed to compare knitted gelatin-coated Dacron bifurcation grafts, knitted collagen-coated Dacron grafts, and stretch polytetrafluoroethylene (PTFE) grafts. METHODS: Between 1991 and 1998, 315 elective patients were randomized by age, gender, diabetes, runoff, indication (aneurysm, aortoiliac occlusive disease), and nicotine consumption at 3 centers of vascular surgery in Austria. The patients received gelatin-coated Dacron (GEL-D) grafts (n = 109), collagen-coated Dacron (COL-D) grafts (n = 100), or stretch PTFE grafts (n = 106). RESULTS: No intraoperative deaths occurred. The 30-day mortality was 3%. No difference was found between the 3 graft materials in long-term patency. The primary 5-year patency rates were 92% for GEL-D, 89% for COL-D, and 91% for stretch PTFE (P =.6001). The secondary 5-year patency rates also differed: 97% for GEL-D, 100% for COL-D, and 97% for stretch PTFE (P =.2062). Early occlusions were observed overall in 3% and late occlusions in 5% of patients. When both Dacron grafts were compared collectively with stretch PTFE, a difference was found in infection rate: Dacron 3% (6/209) versus PTFE 0% (0/106); P <.03. CONCLUSIONS: The bifurcation grafts of all 3 materials were comparable in primary and secondary patency rates, incidence of false aneurysms, and rate of perioperative complications. Graft infections were confined to the 2 Dacron grafts and did not occur in stretch PTFE grafts.

Prosthetic valve endocarditis due to Candida tropicalis complicated by multiple pseudoaneurysms.

Candida endocarditis is an unusual but severe complication caused by Candida albicans or other fungal species. We describe a case of prosthetic valve endocarditis due to Candida tropicalis, complicated by multiple pseudoaneurysms.

Midterm durability of abdominal aortic aneurysm endograft repair: a word of caution.

PURPOSE: Endograft technology for abdominal aortic aneurysm (AAA) repair is being applied more liberally. There is little information about the midterm performance of these grafts. This study is focused on follow-up interventions after endograft repair for AAA. METHODS: Prospective follow-up analysis of a consecutive patient series (n = 173 patients) at a single center who underwent endovascular AAA repair up to 50 months after operation. Seventeen percent of the patients were regarded unfit for open surgery. Four types of commercially available grafts were used. The Society for Vascular Surgery/International Society for Cardiovascular Surgery guidelines were applied for endograft implantation and data preparation. RESULTS: In two patients, the procedure was converted to open surgery. In one procedure, emergency repair for iliac artery rupture was performed. The 30-day mortality rate was 2.8% (n = 5 patients). An early second procedure to correct type I endoleaks was necessary in 8 cases (4.6%; 3-10 days). The following midterm results were obtained: median follow-up of the 166 remaining patients was 18 months (range, 1-50 months); 50 additional procedures were necessary in 37 patients (22.3%) for the treatment of leaks (n = 45 interventions) or to maintain graft patency (n = 5 grafts; four patients with concomitant graft segment disconnection); and 46% of the reinterventions were performed within the first year of follow-up and 74% of the reinterventions were performed within the second year of follow-up. One patient died after emergency surgery for rupture as the result of a secondary endoleak at 1 year. Although seven interventions (14%) were performed for type II endoleak, no serious complications were related to patent sidebranches. There was no statistically significant difference between the need for maintenance in different graft configurations (tubular, bifurcated, aorto-uniiliac), or number of graft segments (1, 2, 3-4, > or = 5 segments). New generation grafts (after 1996) performed better than early generation grafts (P = 0.04, chi-squared test) with regard to endoleak development. CONCLUSION: Endograft repair for AAA is safe but, with current technology, not as durable as open repair. Our data suggest that the use of endograft repair for AAA is becoming safer as endograft design improves. Nevertheless in 26.6% of the patients, there is need for reintervention within midterm follow-up. Close follow-up is crucial because late leaks may develop after more than 2 years after the initial procedure. Endoluminal repair should therefore be applied with caution, strict indication, and only if a tight follow-up is warranted. These findings may also affect health care reimbursement policies.

In vivo magnetic resonance micro-imaging of the human toe at 3 Tesla.

The feasibility of in vivo high-resolution magnetic resonance micro-imaging of fine anatomic structures of human toes was tested. Five healthy subjects were investigated on an experimental 3 Tesla whole body scanner, using standard 3D gradient echo sequences. A radio-frequency surface coil was used for signal detection. Feet, toes and surface coil were comfortably fixed using a home built device for positioning and reduction of motion artifacts. The spatial resolution of 117 x 313 x 375 microm(3) allowed detailed visualization of anatomic structures like skin layers, vessels and nerves. In addition, oval structures with diameters ranging from 500 to 1000 microm were observed in all subjects, which could represent the sensory nerve endings of Vater-Pacinian bodies. Thus, high resolution MR micro-imaging at 3 Tesla may provide improved morphologic information in distal extremities of humans in vivo.

[Endovascular (transfemoral endoluminal aneurysm management; TEAM) versus conventional open therapy in abdominal aortic aneurysms (AAA): analysis of a clinical series]. / Endovaskuläre (Transfemorales Endoluminales Aneurysma Management; TEAM) versus konventionelle offene Therapie des Abdominellen Aortenaneurysmas (AAA): Analyse einer klinischen Serie.

All patients (n = 826) treated electively at the Department of Vascular Surgery University of Vienna, Austria, for their AAA during the years 1965-2000 were analysed with particular emphasis on endoluminal repair. Data collection was carried out in retrospect. The operative mortality or within 30 days was considered the primary endpoint of the study. Since 1995 the TEAM approach was available. From that point in time 45.5% of the AAA were treated electively in the endoluminal way. An exploratory analysis of the clinical series revealed a statistically significant difference in the incidence of various risk factors between groups in favor of open repair. Consequently a conditional regression analysis demonstrated the operative method, median patient's age (above versus below 72 years of age), reduced renal and/or pulmonary function to be of significant influence.

[Preoperative risk factors as deciding criteria in surgical treatment strategy of infrarenal aortic aneurysm]. / Präoperative Risikofaktoren als Entscheidungskriterien in der chirurgischen Behandlungsstrategie des infrarenalen Aortenaneurysmas.

Significant risk factors of operative therapy in patients with infrarenal aortic aneurysms (AAA) were determined. Best treatment strategy (open surgical repair, transluminal endovascular aneurysm management (TEAM) or conservative treatment) was selected on the base of evaluated risk factors, tendency of rupture and life expectancy. Of the typical risk factors impaired renal and/or lung function showed a significant influence on hospital mortality. In patients without these significant risk factors open surgical repair leads to good clinical results. Acceptable postoperative mortality rates after elective exclusion of an AAA with average size in patients presenting significant comorbidities can only be achieved using TEAM. If TEAM can not be performed, open surgery is only justified in the case of very large AAA diameter.

The role of antithrombotic therapy on the patency of peripheral bypasses.

Peripheral bypass surgery is a well-established treatment for symptomatic atherosclerotic disease of the legs. To improve the long-term patency antithrombotic drugs and other adjuvant treatment are applied. In this review we summarize the results of randomized studies concerning antithrombotic treatment for prophylaxis after peripheral bypass surgery. Heparin is used routinely intra- and perioperatively without strong data, and according to few data low molecular weight heparin may be superior in this situation. Aspirin had positive effects in placebo-controlled studies after infrainguinal PTFE-bypasses, furthermore it is recommended due to its general cardiovascular risk reduction. Ticlopidine improved long-term patency in one randomized study after venous bypass surgery. Otherwise there are some data that long-term oral anticoagulation may be preferable in patients after venous bypass surgery.

Prostaglandin E1 reduces ischemia/reperfusion injury by normalizing nitric oxide and superoxide release.

To test the effects of prostaglandin E1 on 2.5 h of ischemia followed by 2 h of reperfusion, continuous nitric oxide measurements (electrochemical) were correlated with intermittent assays of superoxide and peroxynitrite levels (chemiluminescence) and ischemia/reperfusion injury in rabbit adductor magnus muscle. Administering prostaglandin E1 (1 microg/kg) before or during ischemia/reperfusion caused normalization of the release of nitric oxide, superoxide, and peroxynitrite to slightly above preischemic levels. This pattern was dramatically different from that observed during ischemia/reperfusion alone, where nitric oxide concentration increased three times above its basal level. Normalization of constitutive nitric oxide synthase activity in the presence of prostaglandin E1 was associated with a significant reduction of superoxide and peroxynitrite production and subsequent reduction of ischemia/reperfusion injury. At 2 h of reperfusion, vasoconstriction associated with ischemia/reperfusion injury was eliminated, and edema was significantly mollified but still apparent. Prostaglandin E1 treatment does not directly inhibit constitutive nitric oxide synthase, like the inhibitor N(omega)-monomethyl-L-arginine. Some phenomenon associated with ischemia turns on endothelial constitutive nitric oxide synthase to start transforming L-arginine and oxygen into nitric oxide, but prostaglandin E1 seems to inhibit this phenomenon. Thus, essential local L-arginine pools are not depleted, and normal basal levels of essential nitric oxide are maintained, whereas cytotoxic superoxide and peroxynitrite production by L-arginine-deficient constitutive nitric oxide synthase is prevented.