Feasibility of endovascular recanalization of occluded infrapopliteal drug-eluting stents.

PURPOSE: To investigate the safety and feasibility of percutaneous endovascular recanalization of late total occlusions of infrapopliteal drug-eluting stents (DES). METHODS: A retrospective study investigated all 408 infrapopliteal stent procedures performed in 367 patients between January 2007 and October 2013 to identify those who underwent percutaneous reintervention for symptomatic infrapopliteal balloon-expandable DES occlusion. The search identified 49 patients with at least one infrapopliteal DES occlusion in 61 (14.9%) of 408 limbs. Seven (14.3%) patients were excluded from the analysis owing to asymptomatic status (n=6) and acute thrombotic occlusion (n=1), leaving 42 patients who underwent endovascular revascularization of occluded stents in 54 limbs. The study's primary outcomes were technical success and complication rates of endovascular recanalization, while secondary outcomes included limb salvage and the identification of factors influencing primary results. RESULTS: Technical success was 90.7% (49/54 procedures). Technical failure was seen only in cases of stent collapse and overlapping native popliteal artery-infrapopliteal stent occlusion. According to Kaplan-Meier analysis, survival was 89.6%, 81.1%, and 73.5% at 1, 2, and 3 years, respectively, while limb salvage rates were 86.1%, 79.3%, and 72.7% at the same time points. There was 1 (1.8%) case of distal embolization. No factors influencing outcomes could be identified. CONCLUSION: Percutaneous recanalization of infrapopliteal stent total occlusions is safe and feasible. Technical failure was noted in cases of stent deformation occurring at the pedal artery and in overlapping native popliteal artery-infrapopliteal stent occlusion.

Transauricular balloon angioplasty in rabbit thoracic aorta: a novel model of experimental restenosis.

BACKGROUND: The aim of this study was to demonstrate a percutaneous transauricular method of balloon angioplasty in high-cholesterol fed rabbits, as an innovative atherosclerosis model. METHODS: Twenty male New Zealand rabbits were randomly divided into two groups of ten animals, as follows: atherogenic diet plus balloon angioplasty (group A) and atherogenic diet alone (group B). Balloon angioplasty was performed in the descending thoracic aorta through percutaneous catheterization of the auricular artery. Eight additional animals fed regular diet were served as long term control. At the end of 9 week period, rabbits were euthanized and thoracic aortas were isolated for histological, immunohistochemical and biochemical analysis. RESULTS: Atherogenic diet induced severe hypercholesterolemia in both group A and B (2802 ± 188.59 and 4423 ± 493.39 mg/dl respectively) compared to the control animals (55.5 ± 11.82 mg/dl; P < 0.001). Group A atherosclerotic lesions appeared to be more advanced histologically (20% type IV and 80% type V) compared to group B lesions (50% type III and 50% type IV). Group A compared to group B atherosclerotic lesions demonstrated similar percentage of macrophages (79.5 ± 9.56% versus 84 ± 12.2%; P = 0.869), more smooth muscle cells (61 ± 14.10% versus 40.5 ± 17.07; P = 0.027), increased intima/media ratio (1.20 ± 0.50 versus 0.62 ± 0.13; P = 0.015) despite the similar degree of intimal hyperplasia (9768 ± 1826.79 µm² versus 12205 ± 8789.23 µm²; P = 0.796), and further significant lumen deterioration (23722 ± 4508.11 versus 41967 ± 20344.61 µm²; P = 0.05) and total vessel area reduction (42350 ± 5819.70 versus 73190 ± 38902.79 µm²; P = 0.022). Group A and B animals revealed similar nitrated protein percentage (P = NS), but significantly higher protein nitration compared to control group (P < 0.01; P < 0.01, respectively). No deaths or systemic complications were reported. CONCLUSION: Transauricular balloon angioplasty constitutes a safe, minimally invasive and highly successful model of induced atherosclerosis in hyperlipidaemic rabbits.

Evaluation of below-the-knee drug-eluting stents with frequency-domain optical coherence tomography: neointimal hyperplasia and neoatherosclerosis.

PURPOSE: To report the use of intravascular frequency-domain optical coherence tomography (FD-OCT) to detect and characterize in-stent neointimal tissue following infrapopliteal drug-eluting stent (DES) placement in patients suffering from critical limb ischemia. METHODS: This prospective study included 12 patients (7 men; mean age 72.8±7.2 years) who had previously received 21 infrapopliteal sirolimus- or everolimus-eluting stents. The patients returned for regular angiographic follow-up or presented with clinical relapse of symptoms over a mean follow-up of 13.5±7.3 months (range 6-33), at which time FD-OCT imaging was performed. Study endpoints were technical imaging success, defined as successful FD-OCT acquisition and visualization of the arterial lumen and complete vessel wall, and the detection and characterization of in-stent neointimal hyperplasia according to widely accepted OCT criteria. RESULTS: OCT imaging was successfully completed in 19 of the 21 stents. Binary in-stent restenosis (ISR>50%) was detected in 10/19 stents. Percent restenosis was higher after longer follow-up (60.6%±19.8% ≥1 year vs. 35.3%±20.6% <1 year, p=0.03) and in symptomatic vs. asymptomatic patients (61.5%±20.4% vs. 37.2%±19.3%, p=0.04). Neoatherosclerosis findings included lipid-laden neointima (16/19), neointimal neovascularization (13/19), neointimal calcifications (6/19), and thrombus (5/19); no cases of thin-cap fibroatheroma were identified. Neointimal calcifications were more frequent after ≥12 months of follow-up compared to <12 months (46.6% vs. 0%, p=0.02). CONCLUSION: FD-OCT of the infrapopliteal arteries following DES placement is safe and feasible and may demonstrate features of developing neointimal neoatherosclerosis. The latter might play a key role as a mechanism of below-the-knee ISR and warrants further investigation.

Treatment of infrainguinal thromboembolic complications during peripheral endovascular procedures with AngioJet rheolytic thrombectomy, intraoperative thrombolysis, and selective stenting.

OBJECTIVE: This study investigated the safety and effectiveness of the infrainguinal use of the AngioJet rheolytic mechanical thrombectomy system (Possis Medical, Minneapolis, Minn) for the treatment of acute infrainguinal thromboembolism occurring during lower limb revascularization procedures. METHODS: For the interval between January 2000 and January 2011, our hospital's database was meticulously searched for all patients with acute thromboembolism that occurred during lower limb angioplasty, with or without stenting procedures, who were treated with infrainguinal AngioJet thrombectomy. Baseline patient demographics and procedural details were analyzed. Primary end points included technical success, defined as the complete revascularization of the acutely occluded vessel; clinical success, defined as the absence of death or amputation ≤ 60 days; and procedure-related complication. Secondary end points included embolized vessel primary patency and overall patient survival. RESULTS: During this 12-year period, 3147 peripheral percutaneous procedures of angioplasty, with or without stenting, were performed in our department. Intraoperative, clinically, and angiographically evident thromboembolism occurred in 18 of 3147 procedures (0.57%), and 14 (77.7%) were managed using the AngioJet thrombectomy system. In total, 22 arteries were treated (13 infrapopliteal, 3 femoropopliteal, and 6 popliteal arteries). All patients had a completion angiogram for the assessment of the runoff vessels' status. Technical and clinical success occurred in 13 of 14 (92.8%). Adjunctive local thrombolysis or clot trapping, or both, with stenting was used in 64.3% and 42.8% of the procedures, respectively. Mean time follow-up was 38.1 ± 49.0 months. The 1-year embolized vessel primary patency rate was 50.9%, and the survival rate was 53.5% up to 11.5 years of follow-up, as estimated by Kaplan-Meier analysis. The 1-year limb salvage rate was 92.3%. There were no procedure-related minor amputations and one (7.1%) procedure-related major above-knee amputation. CONCLUSIONS: The use of AngioJet rheolytic thrombectomy and adjunctive local thrombolysis or stenting, or both, under filter protection, is safe and effective for the management of severe thromboembolic complications occurring in the femoropopliteal and infrapopliteal arteries during peripheral endovascular procedures.

Long-term outcomes following primary drug-eluting stenting of infrapopliteal bifurcations.

PURPOSE: To investigate the outcomes following primary deployment of drug-eluting stents (DES) for the treatment of infrapopliteal bifurcation lesions in patients suffering from critical limb ischemia (CLI). METHODS: This was a retrospective study of a registry enrolling all patients suffering from chronic infrapopliteal artery disease and undergoing treatment of tibial bifurcation lesions with DES using 3 techniques: balloon and stent (single stent), T-shape double-stent, and culotte double-stent. The analysis included 39 CLI patients (32 men; mean age 69 ± 10 years) who underwent primary stenting of 41 infrapopliteal bifurcations. Most patients (29, 70.7%) were classified as Rutherford category 4. The mean lesion length was 31.3 ± 13.1 mm. The primary endpoints were amputation-free survival, target lesion revascularization (TLR)-free survival, angiographic 2-vessel primary patency (2VPP), and 1-vessel primary patency (1VPP). Secondary endpoints included survival and angiographic binary restenosis. A Cox regression analysis was performed to identify independent predictors influencing outcomes RESULTS: Technical success was achieved in all cases. The mean clinical and angiographic follow-up intervals were 47.5 ± 14.8 and 17.5 ± 12.5 months, respectively. According to the Kaplan-Meier analysis, overall survival, amputation-free survival, and TLR-free survival estimates were 79.5%, 84.3%, and 58.0%, respectively, at 5 years. At 12, 24, and 36 months, the 2VPP rates were 77.2%, 47.5%, and 33.9%, and the 1VPP rates were 84.0%, 65.5%, and 54.5%, respectively. Binary restenosis rates were 26.4%, 57.3%, and 82.2% at 12, 24, and 36 months; restenotic lesions were mainly detected at the origin of the bifurcations. The regression model did not identify any independent predictors influencing outcome. CONCLUSION: DES application for below-the-knee bifurcation lesions was safe and resulted in satisfactory long-term angiographic and clinical outcomes comparable to those reported following infrapopliteal endovascular treatment.

PolarCath cryoplasty enhances smooth muscle cell apoptosis in a rabbit iliac artery model: an experimental in vivo controlled study.

PURPOSE: To in vivo investigate the histological response after single and double cryoplasty therapy in a rabbit iliac artery model. MATERIALS AND METHODS: In total, 40 New Zealand White rabbits underwent percutaneous transluminal angioplasty of the iliac artery using either PolarCath balloon or a conventional angioplasty balloon of equal diameter. Arterial injury, inflammatory response and smooth muscle cells (SMC) apoptosis with the TUNEL (Terminal deoxynucleotidyl transferase dUTP Nick End Labeling) immunohistochemical assay were analyzed. Rabbits were divided between single or double balloon inflation and histological results were compared between cryoplasty and control angioplasty both at 30 min and 72 h. RESULTS: Arterial injury and wall inflammation scores were low and similar between cryoplasty and control groups after single and double balloon inflation. Compared to conventional balloon angioplasty, Polarcath cryoplasty demonstrated superior SMC apoptosis after single inflation at 30 min [12.0±1.2 cells/(0.025 mm)2 vs 7.0±1.5 cells/(0.025 mm)(2), p=0.002], single inflation at 72 h [9.0±1.0 cells/(0.025 mm)(2) vs 5.4±1.4 cells/(0.025 mm)(2), p=0.001], double inflation at 30 min [11.6±1.5 cells/(0.025 mm)(2) vs 6.8±1.4 cells/(0.025 mm)(2), p=0.001] and double inflation at 72h [9.2±0.8 cells/(0.025 mm)(2) vs 5.0±0.7 cells/(0.025 mm)(2), p=0.001]. There were no significant differences in apoptosis between single and double cryoplasty application at 30 min and 72 h. CONCLUSION: Cryoplasty demonstrated superior rates of SMC apoptosis at 30 min and 72 h and was associated to relatively low arterial injury and inflammation scores. An immediate second PolarCath inflation did not achieve superior apoptosis.

Ureteral metal stents: 10-year experience with malignant ureteral obstruction treatment.

PURPOSE: Ureteral patency in malignant ureteral obstruction cases is a therapeutic challenge. We report our long-term experience with palliative treatment for extrinsic malignant ureteral obstruction with percutaneous placement of metal mesh stents. MATERIALS AND METHODS: From January 1996 to December 2005, 90 patients with a mean age of 59 years (range 35 to 80) with ureteral obstruction due to extrinsic ureteral compression and/or encasement by primary or metastatic tumors, or retroperitoneal lymphadenopathy underwent implantation of self-expandable metal mesh stents. A total of 119 ureters were managed. Followup included urinalysis, blood biochemistry tests and transabdominal ultrasound or intravenous urography. RESULTS: The technical success rate of percutaneous antegrade insertion of ureteral self-expandable metal mesh stents was 100%. Renal biochemistry normalized and hydronephrosis gradually resolved 1 to 2 weeks after stent insertion. Median followup was 15 months (range 8 to 38). Hyperplastic reaction and/or encrustation, or tumor ingrowth developed in 45 stents. Secondary intervention, such as repeat balloon dilation and coaxial stenting, was done to improve patency. Migration was observed in 13 metal stents. The primary and secondary patency rates during followup were 51.2% and 62.1%, respectively. A double pigtail or external-internal stent was inserted in 45 cases in which secondary interventions did not ensure patency. CONCLUSIONS: Internal drainage of extrinsic malignant ureteral obstruction with metal mesh stents provides long-term decompression of the upper urinary tract in select cases. Certain problems limit the application of metal mesh stents in the ureter. Further studies are warranted to identify independent predictors of ureteral patency after the application of metal stents for malignant obstruction.

Thrombin promotes arteriogenesis and hemodynamic recovery in a rabbit hindlimb ischemia model.

BACKGROUND: Compared with angiogenesis, arteriogenesis is a distinct process based on the remodeling and maturation of pre-existing arterioles into large conductance arteries. Therapeutic angiogenesis has been proposed as a potential treatment for ischemic atherosclerotic diseases. Since a variety of angiogenic factors have been tested with inconsistent so far clinical results, the challenge remains in identifying the factor(s) that will stimulate functional neovascularization. Thrombin has been reported to play a pivotal role in the initiation of angiogenesis by regulating and organizing a network of angiogenic mediators. Also, it was recently demonstrated that thrombin is a potent anti-apoptotic factor for endothelial cells, providing evidence on a potential role of thrombin in vascular protection and maintenance of vessel integrity. Based on these observations, we hypothesized that thrombin may promote the development of mature functional blood vessels. METHODS: Seventy-four (n=74) rabbits underwent bilateral femoral artery surgical excision. On the 20th postsurgical day increasing doses of VEGF or bFGF or thrombin were injected in one ischemic limb per rabbit and an equal volume of normal saline to the contralateral control limbs. Quantification of newly developed collateral vessels (diameter >500 mum) was performed by transauricular intra-arterial subtraction angiography. Computerized quantitative analysis of collateral vessels in angiography images was based on the concept of multiscale structural tensor. Perfusion analysis of an in vivo dynamic computed tomography study was performed to investigate hemodynamic recovery of the distal ischemic limbs. Tissue perfusion analysis was performed with the semiquantitative slope methodology, which focuses on the first-pass arterial phase. RESULTS: A single administration of thrombin exhibited a dose-dependent increase of arteriogenic outcome. Thrombin at 5000 IU induced a 30.2 +/- 7.4% (P < 0.05) increase of total collateral area and length. Both VEGF and bFGF were without any significant effect at the concentrations used. Functional estimation of limb perfusion showed a statistically significant increase of blood flow recovery only for thrombin. The semiquantitative slope method perfusion score differed significantly in the 5000 IU thrombin treated limbs (5.7 +/- 0.3 vs 5.0 +/- 0.3 in control ischemic limbs; P < .05), and was not significantly inferior from the score of normal nonoperated limbs (6.5 +/- 0.3) suggesting a trend towards hemodynamic recovery of distal limb perfusion. CONCLUSIONS: In a rabbit hindlimb ischemia model, thrombin promoted the formation of large collateral vessels and improved the perfusion of distal ischemic tissue. These results provide new insights in understanding the involvement of thrombin in vascular formation and point to a novel role of thrombin in arteriogenesis.

Risk for transient ischemic attacks is mainly determined by intima-media thickness and carotid plaque echogenicity.

BACKGROUND: Stenosis severity, plaque morphology, and intima-media thickness (IMT), all have been found to provide prognostic information in patients with asymptomatic carotid artery disease. However, limited data exist on the association between these parameters and the risk for transient ischemic attack (TIA). METHODS: We compared the ultrasonographic characteristics of 88 consecutive patients with first TIA without known cardioembolic source with those of 176 propensity-matched asymptomatic control subjects. RESULTS: IMT was higher in TIA patients compared to control subjects (0.74+/-0.14 mm versus 0.68+/-0.13 mm, p=0.001). Plaques were found in 70.5% of patients and 64.8% of controls (p=0.407). Compared with controls, TIA patients demonstrated more frequently predominantly echolucent lesions (77.4% versus 56.1%, p=0.005) and high-grade carotid stenoses (21.0% versus 9.6%, p=0.042). TIA patients with low-to-moderate grade (<70%) lesions exhibited higher IMT and more prevalent echolucent morphology in comparison with their control counterparts. No significant differences were observed between groups regarding high-grade lesions. In multivariate models, IMT and plaque echogenicity, but not stenosis severity, emerged as independent determinants of risk. CONCLUSIONS: Risk for TIA is primarily associated with IMT and plaque echogenicity, especially in the absence of high-grade lesions. Stenosis severity appears to be of limited prognostic value.

Application of paclitaxel-eluting metal stents in renal artery of pig model.

BACKGROUND AND PURPOSE: Recent reports concerning coronary, carotid, and femoral vasculature have proposed the use of drug-eluting metal stents (MS) to improve clinical and angiographic outcomes. Based on these reports, we used paclitaxel-eluting MS within an animal renal artery lumen and compared the results with those using a bare-metal stent. MATERIALS AND METHODS: The experimental model in this study was the female pig renal artery. Ten pigs with weights ranging from 25 to 30 kg were used. Twenty stents were placed, two in each animal. The MS placement was randomly performed in either the right or left renal artery of each animal. In 10 arteries, a 3.5 x 18 mm R-stent (group A) was placed; in the remaining 10 arteries, a 3 x 32 mm paclitaxel-eluting coronary stent (T-stent, group B) was inserted. Patency was estimated with the use of digital subtraction angiography, CT angiography, and virtual endoscopy at 24 hours and 1 month poststent placement. RESULTS: The positioning of the MS was successful in all cases. The initial angiographic result was maintained 24 hours after the intervention. No stent migration was seen, except for one paclitaxel stent that was acutely occluded. The one-month patency rate, as demonstrated by angiography, CT angiography, and virtual endoscopy, was 70% (8 arteries) in group A and 90% (9 arteries) in group B. The thickness of the endothelium and of the muscular coat was statistically significantly less in group B compared with group A (P = 0.0352 and P = 0.0046, respectively). CONCLUSION: These preliminary experimental study results suggest that the paclitaxel-eluting MS is more efficient than the bare-metal stent when used within the pig renal artery. Further experimental and clinical studies are necessary to validate our preliminary encouraging results.

Trends and future needs in clinical radiology: insights from an academic medical center.

OBJECTIVE: Advances in technology, expanding indications and defensive medical practice, in combination with population aging, have all contributed to a substantial increase in utilization of imaging and therapeutic radiology procedures in recent years. Moreover, the integration of education, innovation and research into high-volume workflow, although challenging, is a key requirement in teaching hospitals. Therefore, identifying forthcoming demand in the use of radiology services at a referral center might be of special interest and facilitate health policy planning in this context. METHODS: Data regarding conventional radiographic, ultrasonographic and computed tomography (CT) investigations, radiotherapy sessions, and interventional procedures were collected for a 5-year period (2000-2004). Based on these observations, we deployed appropriate models to forecast utilization rates in 2005-2009. RESULTS: Between 2000 and 2004, ultrasound examinations increased by 31.8%, mammography by 31.6%, CT scans by 17.4%, interventions by 14.5% and radiotherapy sessions by 13.9%, while conventional investigations decreased by 42.5%. We identified significant increasing trends for ultrasound, mammography, CT and interventions (all p<0.001 for linear component). Compared to current levels, the workload for these modalities is expected to rise in the next 5 years by 43%, 31%, 20% and 14%, respectively. Radiotherapy sessions demonstrate an unstable, non-significant increasing trend (p=0.189), while utilization of conventional radiography declines rapidly (p<0.001 for linear trend, 5-year prediction -51%). CONCLUSIONS: In forthcoming years, the demand for radiology services at referral centers will increase substantially. Advances in digital technology alone will not suffice to completely alleviate the need for additional resources and well-trained personnel.

Non-palpable breast carcinomas: correlation of mammographically detected malignant-appearing microcalcifications and epidermal growth factor receptor (EGFR) family expression.

Malignant-appearing microcalcifications (MAMCs) represent one of the earliest mammographic findings of non-palpable breast carcinomas (NPBCs). In the present study, we have evaluated the expression of all EGFR family members in NPBCs and its possible association with MAMCs. Three hundred and fifty patients with non-palpable suspicious breast lesions detected during screening mammography were studied. EGFR family proteins' expression was found to be present since the preclinical phase of breast carcinomas and was strongly correlated (except HER-3) with MAMCs. The co-expression pattern of EGFR family members combined with other molecular prognostic factors and the mammographic appearance might predict the natural history of NPBCs.

Splenic arteriovenous fistula and sudden onset of portal hypertension as complications of a ruptured splenic artery aneurysm: Successful treatment with transcatheter arterial embolization. A case study and review of the literature.

Splenic arteriovenous fistula (SAVF) accounts for an unusual but well-documented treatable cause of portal hypertension([1-4]). A case of a 50-year-old multiparous female who developed suddenly portal hypertension due to SAVF formation is presented. The patient suffered from repeated episodes of haematemesis and melaena during the past twelve days and thus was emergently admitted to hospital for management. Clinical and laboratory investigations established the diagnosis of portal hypertension in the absence of liver parenchymal disease. Endoscopy revealed multiple esophageal bleeding varices. Abdominal computed tomography (CT) and transfemoral celiac arteriography documented the presence of a tortuous and aneurysmatic splenic artery and premature filling of an enlarged splenic vein, findings highly suggestive of an SAVF. The aforementioned vascular abnormality was successfully treated with percutaneous transcatheter embolization. Neither recurrence nor other complications were observed.

Virtual endoscopy of the urinary tract.

Technological breakthroughs have advanced the temporal and spatial resolutions of diagnostic imaging, and 3 dimensional (3-D) reconstruction techniques have been introduced into everyday clinical practice. Virtual endoscopy (VE) is a non-invasive technique that amplifies the perception of cross-sectional images in the 3-D space, providing precise spatial relationships of pathological regions and their surrounding structures. A variety of computer algorithms can be used to generate 3-D images, taking advantage of the information inherent in either spiral computed tomography or magnetic resonance imaging (MRI). VE images enable endoluminal navigation through hollow organs, thus simulating conventional endoscopy. Several clinical studies have validated the diagnostic utility of virtual cystoscopy, which has high sensitivity and specificity rates in the detection of bladder tumor. Published experience in the virtual exploration of the renal pelvis, ureter and urethra is encouraging but still scarce. VE is a safe, non-invasive method that could be applied in the long-term follow-up of patients with ureteropelvic junction obstruction, urinary bladder tumors and ureteral and/or urethral strictures. Its principal limitations are the inability to provide biopsy tissue specimens for histopathologic examination and the associated ionizing radiation hazards (unless MRI is used). However, in the case of endoluminal stenosis or obstruction, VE permits virtual endoluminal navigation both cephalad and caudal to the stenotic segment. To conclude, VE provides a less invasive method of evaluating the urinary tract, especially for clinicians who are less familiar with cross-sectional imaging than radiologists.

Digital subtraction angiography and computer assisted image analysis for the evaluation of the antiangiogenetic effect of ionizing radiation on tumor angiogenesis.

PURPOSE: The aim of the present study was to evaluate and quantify the antiangiogenetic effect of ionizing radiation on tumor angiogenesis using digital subtraction angiography (DSA) in conjunction with computer assisted image analysis (CAIA). METHODS: Walker 256 carcinosarcoma was inoculated in both glutei of 12 Wistar rats. When the tumors reached a diameter of 1.5 cm, local irradiation of the right gluteus was performed. The left gluteus of each animal served as a control. After 24 hours of irradiation, angiography was performed, and images where digitized and subsequently processed. The effect of irradiation was observed both in big and small vessels (smaller or greater than 200 microm). RESULTS: Irradiated areas of both small and big vessels showed a statistically significant reduction in both total vessel area and length. Small vessels showed a greater trend toward suppression by irradiation (not statistically significant). CONCLUSION: Irradiation had a deleterious effect in both macro- and micro-blood supply of a tumor. The use of CAIA enhanced the efficacy of DSA and enabled the in vivo identification of the effect of irradiation on various caliber vessels as well as the ratios of total length and total area of small and big vessels.

External beam radiation therapy reduces the rate of re-stenosis in patients treated with femoral stenting: results of a randomised study.

BACKGROUND AND PURPOSE: To evaluate the feasibility and efficacy of external beam irradiation (EBI) for the prevention of re-stenosis due to neointimal hyperplasia, after percutaneous transluminal angioplasty (PTA) and stent placement of the superficial femoral artery. PATIENTS AND METHODS: A total of 60 patients with the diagnosis of superficial femoral artery stenoses or occlusions due to peripheral arterial obstructive disease underwent PTA and implantation of a self-expandable stent at their superficial femoral artery. After the procedure, patients were randomised and 30 of them received EBI (6 MV photons, total dose 24 Gy in six fractions in 2 weeks), while the rest 30 received no radiation therapy. RESULTS: EBI was technically feasible in all patients, without serious radiation related side effects. Overall, a statistically significant difference was observed in stenosis categories between the two groups at 6 months follow-up (P=0.04). More specifically, significantly more patients in the control group presented with stenosis greater or equal than 70% [EBI group 30% (9/30); control group 66.7% (20/30); P=0.009]. This difference in the percentage of re-stenosis had as a consequence significantly lower re-intervention rates among the patients of the irradiated group [17% (5/30) versus 47% (14/30); P=0.025] during the 6 months follow-up period. We also observed that the irradiated patients had re-stenosis at the stent ends, while the non-irradiated had re-stenosis at the stent ends and the lumen. Three of the irradiated patients, who discontinued the anti-platelet treatment, have shown thrombosis of the irradiated artery during the first month from the completion of the treatment. CONCLUSIONS: It is our belief that EBI is a feasible, safe and effective method for the prevention of neointimal hyperplasia at the superficial femoral artery. Further studies are deemed necessary to optimise the radiotherapy schedule.

Hemobilia secondary to hepatic artery pseudoaneurysm: an unusual complication of bile leakage in a patient with a history of a resected IIIb Klatskin tumor.

We report a case of a 74-year-old woman with a 16-year history of a double bilo-enteric anastomosis due to resected hilar cholangiocarcinoma (Type IIIb Klatskin tumor). The patient presented with cholangitis secondary to benign anastomotic stenosis which resulted in a large intrahepatic biloma. In order to restore the patency of the anastomosis and overcome cholangitis, several attempts took place, including endobiliary stenting, balloon-assisted biloplasty and transhepatic billiary drainage. Anastomotic patency was achieved, complicated, however, by persistent upper gastro-intestinal bleeding, presented as hemobilia. A biloma-induced pseudoaneurysm of the left hepatic artery was diagnosed. This had ruptured into the biliary tract, and presented the actual cause of the hemobilia. Selective embolism of the pseudoaneurysm resulted in control of the hemorrhage, and was successfully combined with transhepatic dilatation of the anastomosis and percutaneous drainage of the biloma. The patient was ultimately cured and seems to be in excellent condition, 5 mo after treatment.

Ureteral metal stents: a tale or a tool?

There are four types of ureteral metal stents: self expandable, balloon expandable, covered, and thermoexpandable shape-memory. Insertion of metal stents requires expertise with transurethral and percutaneous techniques. The stricture is traversed with the aid of a guidewire via a percutaneous nephrostomy, and the stenotic segment is dilated using a high-pressure balloon catheter. The stent is then inserted over the guidewire, such that the upper end bypasses the obstruction by at least 3 to 4 cm, while the lower end extends intravesically for 0.5 to 1 cm from the ureteral orifice. If necessary, two or more stents are placed in sequence, overlapping by at least 2 to 3 cm. Metal stents were initially used for the relief of end-stage malignant disease, and their role in the treatment of benign ureteral strictures is still undefined. Patients often complain of abdominal discomfort and mild pain after stent insertion, which soon resolve spontaneously. Hematuria usually stops after a few days and does not necessitate any treatment. Mild urothelial hyperplasia in the stent lumen is common but usually regresses after 4 to 6 weeks. Many authors suggest the use of a double-pigtail catheter for the first 4 to 6 weeks to avoid narrowing of the ureteral lumen. The influence of stents on ureteral peristalsis is a major but poorly documented issue. Encrustation is a significant problem that needs to be addressed. The characteristics of both the patient and the stent influence its likelihood. Migration of coated metal stents was seen in 81% of patients at our center. Virtual endoscopy has recently been introduced as a tool for the follow-up of patients with stented ureters. Further design development is necessary to obtain the ideal ureteral metal stent. In a recent study in female pigs, paclitaxel-eluting metal stents engendered less inflammation and hyperplasia of the surrounding tissues.

Percutaneous rheolytic thrombectomy for treatment of acute renal-artery thrombosis.

PURPOSE: We present our experience with percutaneous rheolytic treatment with the AngioJet thrombectomy catheter for acute renal-artery thrombosis. CASE REPORT: A 63-year-old male patient with renal-artery thrombosis presented 48 hours after the onset of acute nonradiating flank pain. Thrombosis was documented by CT angiography, 99mTc-DTPA, and digital subtraction angiography. A percutaneous thrombectomy was performed with the AngioJet catheter. At the end of the procedure, the arterial lumen was patent, and no underlying stenosis or other deformity of the arterial wall was found. Thus, the cause of the obstruction was considered to be an embolus. After the procedure, urokinase was given to prevent distal occlusions from emboli that could have escaped mechanical thrombectomy. Heparin was also administered. The patient was released from the hospital with a patent renal unit and ameliorated serum creatinine concentration. CONCLUSION: We propose the use of the AngioJet thrombectomy catheter for the percutaneous treatment of acute renal-artery thrombosis.

Outflow protection filters during percutaneous recanalization of lower extremities' arterial occlusions: a pilot study.

PURPOSE: Filter devices are already employed for the protection of carotid, coronary and renal distal vascular bed during endovascular procedures. This is a pilot study investigating their feasibility, safety and distal emboli protection capability during recanalization of lower extremities' acute and subacute occlusions. MATERIALS AND METHODS: Study population included 16 patients, 11 with a subacute arterial occlusion and 5 with an acute episode. The Trap filter (Microvena, USA) and its successor the Spider filter (EV3, USA) were utilized. Subacute occlusions were dealt with standard angioplasty and stenting procedures, while acute ones were managed primarily with Angiojet rheolytic thrombectomy. Outflow arterial tree was checked angiographically in-between consequent procedural steps. Embolic material collected after filter recovery was analyzed histopathologically. Patients' follow-up was scheduled at 1 month. RESULTS: Seventeen filter baskets were applied in the recanalization of 16 target lesions in total. Mean length of the occluded segments was 6.1 (range: 2-15 cm; S.D. = 3.7 cm). Mean in situ time of the filters was 38.75 min (range: 20-60 min; S.D. = 12.71 min). Technical success rate of deployment and utilization of the filtration devices was 100% (17/17). Procedural success rate of the recanalization was 100% (16/16) without any clinical or angiographic evidence of periprocedural distal embolization. Macroscopic particulate debris was extracted from all the filters (17/17) containing fresh thrombus, calcification minerals, cholesterol and fibrin. Mean diameter of the largest particle per specimen was 1702.80 (range: 373.20-4680.00 microm; S.D. = 1155.12 microm). No adverse clinical events occurred at 1-month follow-up with 100% limb salvage (16/16). CONCLUSION: The application of outflow protection filters is safe, feasible and efficacious in hindering distal embolization complications and safeguarding the distal capillary bed. Nevertheless, this is a pilot study in a limited group. Further studies have to be contacted in order to provide evidence for a more general use of these devices.