Effect of Sac Asymmetry, Neck and Iliac Angle on the Hemodynamic Behavior of Idealized Abdominal Aortic Aneurysm Geometries.

BACKGROUND: Abdominal aortic aneurysms (AAAs) are currently treated based on the universal maximum diameter criterion, but other geometric variables may play a role in the risk of rupture. The hemodynamic environment inside the AAA sac has been shown to interact with several biologic processes which can affect prognosis. AAA geometric configuration has a significant impact in the hemodynamic conditions that develop, which has only been recently realized, with implications for rupture risk estimations. We aim to perform a parametric study to evaluate the effect of aortic neck angulation, angle between the iliac arteries, and sac asymmetry (SA) on the hemodynamic variables of AAAs. METHODS: This study uses idealized AAA models and it is parametrized in terms of 3 quantities as follows: the neck angle, φ (°), iliac angle, θ (°), and SA (%), each of which accepts 3 different values, specifically φ = (0°, 30°, 60°), θ = (40°, 60°, 80°), and SA = (S, °SS, °OS), where the SA can either be on the same side with respect to neck (SS) or on the opposite side (OS). Time average wall shear stress (TAWSS), oscillatory shear index (OSI), relative residence time (RRT), and the velocity profile are calculated for different geometric configurations, while the percentage of the total surface area under thrombogenic conditions, using thresholds previously reported in the literature, is also recorded. RESULTS: In case of an angulated neck and a higher angle between iliac arteries, favorable hemodynamic conditions are predicted with higher TAWSS and lower OSI and RRT values. The area under thrombogenic conditions reduces by 16-46% as the neck angle increases from 0° to 60°, depending on the hemodynamic variable under consideration. The effect of iliac angulation is present but less pronounced with 2.5-7.5% change between the lower and the higher angle. The effect of SA seems to be significant for OSI, with a nonsymmetrical configuration being hemodynamically favorable, which in the presence of an angulated neck is more pronounced for the OS outline. CONCLUSIONS: Favorable hemodynamic conditions develop inside the sac of idealized AAAs with increasing neck and iliac angles. Regarding the SA parameter, asymmetrical configurations most often appear advantageous. Concerning the velocity profile the triplet (φ, θ, SA) may affect outcomes under certain conditions and thus should be taken into account when parametrizing the geometric characteristics of AAAs.

Late Neck Related Adverse Events are Rare Among Patients with Wide Aortic Neck Undergoing Endovascular Aneurysm Repair with the Ovation Endograft.

BACKGROUND: Patients with wide aortic necks undergoing Endovascular Aneurysm Repair (EVAR) have been shown to be at a higher risk for neck-related complications. We aim to examine outcomes of EVAR with an endograft exerting minimal outward pressure (Ovation-Endologix) in patients with a large baseline neck diameter. METHODS: We performed a retrospective single center study, including consecutive patients undergoing EVAR with the Ovation system from May 2011 to April 2021. Patients were divided in Groups 1 and 2 if the 20, 23, 26, 29 mm or the 34 mm proximal diameter main body was used, respectively. According to the instructions for use of the device, for neck diameters 27-30 mm the 34 mm main body is required. Primary endpoint was rate of neck related complications during follow-up, (type Ia endoleak, migration >10 mm and neck-related re-interventions) and rate of aortic neck dilatation (AND). AND was determined based on multiple aortic neck diameters that were recorded and compared between the 1-month computed tomography angiography (CTA) after EVAR and the last available follow-up CTA.Secondary endpoints were peri-procedural and follow-up outcomes such as endoleaks, reinterventions and overall mortality. RESULTS: In total 281 patients were included, 222 in Group 1 and 59 in Group 2. Patients in Group 2 presented significantly shorter neck length, higher neck angulation and more common reversed tapered configuration. Median follow-up was 36 months (Range: 6-106). Early and late type Ia endoleak was observed in 4 and 2 patients in each group, respectively (P = 0.063 and P = 0.195, respectively). Distal migration was observed in 2 patients in Group 2 and AND was recorded in 2 patients in each group (P = 0.195). Freedom from the primary endpoint was estimated at 98%, 94%, 94% at 12-, 36-, 60-months for Group 1 and at 98%, 95%, 86% for Group 2 (P-Value 0.266). Probability of survival was 95%, 86%, 75% at 12-, 36-, 60-months for Group 1 and 83%, 77%, 72% for Group 2 (P-Value 0.226).Multivariate regression analysis identified neither Group 1 versus Group 2 nor absolute value of aortic neck diameter as significant predictors of neck-related adverse events. Neck diameters did not display significant differences over time in any of the levels evaluated. CONCLUSIONS: EVAR with the Ovation endograft results in low rates of late neck related complications which is also true for patients with wide baseline aortic necks.

Dual-Energy Computed Tomography as an Adjunct in the Evaluation of Peripheral Chronic Total Occlusions: A Feasibility Study.

This study investigated the role of dual-energy computed tomography (CT) for lesion characterization in patients with peripheral arterial disease manifesting with chronic total occlusions (CTOs). Forty-one symptomatic patients with CTOs underwent dual-energy CT angiography before endovascular treatment. The lesions were subsequently analyzed in a dedicated workstation, and 2 indexes-dual-energy index (DEI) and effective Z (Zeff)-were calculated, ranging from 0.0027 to 0.321 and from 6.89 to 13.02, respectively. Statistical analysis showed a significant correlation between the DEI and Zeff values (P < .001). The interobserver intraclass correlation coefficient was 0.91 for the mean Zeff values and 0.86 for the mean DEI values. This technique could potentially provide useful information regarding the composition of a CTO.

Discrimination of High-Risk Type-2 Endoleak after Endovascular Aneurysm Repair through CT Perfusion: A Feasibility Study.

A type-2 endoleak after an endovascular aneurysm repair is the most prevalent type of endoleak, but as the clinical consequence of its diagnosis is uncertain, at present, management decisions are solely based on aneurysm sac growth. The aim of this study was to investigate the potential of various computed tomography perfusion parameters for their ability to distinguish high-risk type-2 endoleaks from low-risk type-2 endoleaks after an endovascular aneurysm repair.

The Use of a Suture Mediated Vascular Closure Device to Achieve Hemostasis following Arterial Access through Previously Implanted Synthetic Grafts.

BACKGROUND: Percutaneous endovascular aneurysm repair (EVAR) and peripheral interventions using the Perclose Proglide suture mediated system has not been adequately studied in patients with synthetic grafts at access sites. METHODS: We report the use of the Perclose Proglide in 10 patients in whom previously inserted synthetic grafts in the groin were punctured for arterial access (5 for peripheral interventions and 5 undergoing EVAR). In patients undergoing peripheral interventions a single device was used, while in patients undergoing EVAR 2 devices were employed per access site. The preclosing technique was used in every case. RESULTS: Hemostasis was achieved in all patients. No complications were observed except for a small laceration and a localized hemodynamically nonsignificant stenosis, without any clinical sequel. CONCLUSIONS: This small case series indicates the feasibility of percutaneous access with the Perclose Proglide system to perform EVAR and peripheral endovascular interventions in the presence of synthetic grafts in the groin, with promising outcomes.

Aggressive recurrence of Non-Hodgkin's Lymphoma after successful clearance of hepatitis C virus with direct acting antivirals.

The association of Non-Hodgkin lymphomas and Hepatitis C virus is well documented and antiviral treatments facilitate a virological and hematological response in the majority of HCV related Non-Hodgkin lymphomas. The recent years, direct acting antivirals have made cure possible almost for every HCV patient. Some concerns were raised as regards the frequency and the pattern of recurrence in HCV patients with HCC, treated with these agents. We present a patient with DLBCL, in remission after appropriate treatment, HCV cirrhosis that was cured with the new antivirals and shortly after SVR, he experienced a lethal lymphoma recurrence.

Endovascular Treatment of Malignant Superior Vena Cava Syndrome through Upper-Limb Access: A Comparison between Venous-Dedicated and Conventional Stents.

PURPOSE: To retrospectively evaluate the technical and clinical outcomes of superior vena cava (SVC) stent placement through upper-limb venous access in malignant SVC syndrome (SVCS) and compare the efficacy of different nitinol stent types. MATERIALS AND METHODS: Between 2006 and 2018, 156 patients (132 male; mean age, 62 y; age range, 33-81 y) underwent SVC stent placement for malignant obstructions through upper-limb venous access with 1 of 3 types of nitinol stent: 1 venous-dedicated (Sinus-XL stent) and 2 non-venous-dedicated (E-Luminexx Vascular Stent and Protégé GPS). Cases of common femoral vein access or non-nitinol stents were excluded from further analysis. The mean duration of follow-up was 8 mo. RESULTS: Technical success was achieved in 99.3% of cases. One patient died during the procedure as a result of cardiac tamponade. Balloon predilation was performed in 10 patients and postdilation in 126. Mean procedural time was 34.4 min (range, 18-80 min). Overall survival rates were 92.3%, 57.3%, and 26.8%, and overall primary patency rates were 94.5%, 84.8% and 79.6%, at 1, 6, and 12 mo, respectively. There were no statistically significant differences in primary patency rates between venous- and non-venous-dedicated stents or among different Stanford SVCS grading groups (P > .05). CONCLUSIONS: SVC stent placement through an upper-limb approach is a safe, fast, and effective technique. There is no evident benefit of venous-dedicated vs non-venous-dedicated stents in the treatment of malignant SVCS.

CT Foot Perfusion Examination for Evaluation of Percutaneous Transluminal Angioplasty Outcome in Patients with Critical Limb Ischemia: A Feasibility Study.

PURPOSE: To evaluate foot perfusion in patients with critical limb ischemia (CLI) using quantitative perfusion multi-detector-row CT and estimate perfusion parameter changes before and after percutaneous transluminal angioplasty (PTA). MATERIALS AND METHODS: This prospective study investigated 13 patients (10 men; median age, 72 y; range, 51-84 y) with CLI who underwent CT foot perfusion examinations with a 128-slice dual-energy CT scanner 1 day before and 1 week after PTA. Key parameters such as permeability surface (PS), blood volume (BV), and blood flow (BF) were analyzed and compared statistically. The studies were also examined by a second observer to determine interobserver reproducibility. RESULTS: Revascularization was technically successful in all patients, and mean ankle-brachial index increased from 0.36 ± 0.16 to 0.75 ± 0.22. After revascularization, mean BV increased from 1.55 mL/100 g ± 0.83 to 4.51 mL/100 g ± 1.53, BF increased from 16.28 mL/100 g/min ± 4.97 to 31.49 mL/100 g/min ± 6.86, and PS increased from 3.1 mL/min/100 g ± 1.95 to 8.67 mL/min/100 g ± 3.85 (P < .05). Patients with poor response to revascularization who finally underwent amputation presented lower post-PTA perfusion parameters values than patients with significant clinical improvement (P < .05). All measurements demonstrated very good interobserver reproducibility, and intraclass correlation coefficients were 0.91 for BV, 0.94 for BF, and 0.95 for PS. The mean effective dose of the examination was estimated at 0.29 mSv. CONCLUSIONS: CT foot perfusion is a reproducible technique that may be a useful modality for the estimation of PTA outcome. Significant restitution of perfusion parameters was observed after successful revascularization.

Occupational exposure during endovascular aneurysm repair (EVAR) and aortoiliac percutaneous transluminal angioplasty (PTA) procedures.

OBJECTIVES: The purpose of this study was to determine the radiation exposure of primary interventionalist's different body parts during endovascular aneurysm repair (EVAR) procedures and aortoiliac percutaneous transluminal angioplasty (PTA) procedures and to evaluate the efficacy of a radioprotective drape. METHODS: Occupational doses for 36 consecutive aortoiliac PTA procedures and 17 consecutive EVAR procedures were estimated using thermoluminescence dosimetry (TLD) chips (TLD-200, Hashaw, Solon, OH). Effective dose (ED) was calculated using the Niklason algorithm. For the evaluation of a 0.25 mm Pb equivalent drape (Ecolab, Saint Paul, Minnesota, USA), experiments were performed using two physical anthropomorphic phantoms (Rando-Alderson Research Labs, CA, USA). RESULTS: Median ED for a typical EVAR and PTA procedure was 4.7 ± 1.4 µSv and 4.4 ± 3.6 µSv, respectively. The highest radiation doses were measured for the operator's hands in both procedures. Moreover, considerable doses were measured to the operator's head, eye lenses and thyroid. Due to the use of the drape, radiation exposure of primary operator's abdominal area, genitals, thyroid and eye lenses was reduced by an average of 59%, 60%, 65% and 59%, respectively. However, dose area product (DAP) and peak skin dose (PSD) were increased by 20% when part of the drape was placed into the X-ray field. CONCLUSION: During EVAR and PTA procedures, primary operator's organs are exposed to considerable radiation doses. Occupational radiation exposure can be reduced significantly with the proper use of a radioprotective drape.

Routine use of an aortic balloon to resolve possible inflow stenosis induced by the inflatable ring fixation mechanism of the Ovation endograft.

PURPOSE: To investigate if the routine use of an aortic balloon within 15-30 min after Ovation stent graft ring inflation would resolve any inflow stenosis, which may reach 60 %, at the level of the sealing rings. Moreover, we estimated the potential hemodynamic compromise in these patients during rest and exercise. METHODS: Following 3-dimensional reconstruction of AAA models, cross-sectional area of the infrarenal aorta just proximal the sealing mechanism (A aort, R aort, respectively) and internal area at the site of stenosis (A int, R int, respectively) were measured for 83. Forty-nine patients were managed without and 34 with an aortic balloon use. Pressure drop during rest and exercise was estimated. RESULTS: Technical success was 98 % and there were no perioperative deaths, one type-I endoleak, and 12 (14.5 %) type-II endoleaks. Median A int and R int were significantly reduced compared to A aort [55 % reduction, 143 (range 28-380) mm2 vs 314 (range 177-531) mm2, P value <0.001] and R aort [42 % reduction, 6.75 (range 3-11) mm vs 10 (range 7.5-13) mm, P value <0.001]. The observed stenosis was significantly less for patients in whom an aortic balloon was used intraoperatively (area reduction 36 vs 59 %, P value = 0.009). This stenosis caused a statistically significant, but clinically insignificant ΔP in both groups during rest (0.13 vs 0.06 mmHg, P value = 0.02) and exercise (1 vs 0.5 mmHg, P value = 0.02). CONCLUSION: The advantages of the unique sealing mechanism of the Ovation device seem to be accompanied by an inflow stenosis which is significantly reduced when neck molding with an aortic balloon is used. Overall, the hemodynamic impact of this abnormality seems to be clinically insignificant at 1-month follow-up.

ePTFE stent graft in non-steno-occlusive arterial disease: 2 centers retrospective study.

PURPOSE: We report our experience regarding use of Fluency stent graft (Bard, Murray Hill, NJ, USA) for the treatment of peripheral aneurysms, pseudoaneurysms, arteriovenous fistulae, dissections and arterial ruptures, lacerations or perforations. METHODS AND MATERIALS: This two-center study included 59 patients (40 M, 19 F) with a mean age of 64.37 years (range 20-91 years). In total 61 lesions were treated, so subdivided: 10 true aneurysms, 26 pseudoaneurysms, 5 iatrogenic arteriovenous fistulae, 20 arterial ruptures, lacerations or perforations. RESULTS: Immediate technical success was obtained in 60 of 61 lesions (98.3 %); in 1 case (pseudoaneurysm of hepatic artery) additional embolization of the gastroduodenal artery with microcoils was needed. Follow-up was available for 57 patients and 59 lesions; mean period was 23.52 months (range 1-60 months). At 1-year primary patency was 89.47 %, whereas secondary patency was 96.4 %. CONCLUSION: Endovascular application of Fluency stent graft seems to offer an effective, and durable less invasive alternative to standard surgical techniques for the treatment of peripheral aneurysms, pseudoaneurysms, iatrogenic arteriovenous fistulae and arterial ruptures, or penetrating injuries.

Bifurcated aortoiliac endograft limb occlusion during deployment and its bailout conversion using the external iliac artery to internal iliac artery endograft technique.

Endovascular aneurysm repair has become the preferred method to treat abdominal aortic aneurysms (AAAs). The Ovation TriVascular Stent-Graft system introduces a unique concept of separation of the metal (stent) and fabric (graft) portion of the endograft's main body to facilitate delivery through ultra-low profile 14F devices. In the setting of a narrow distal aneurysmal lumen, usually due to the presence of thrombus, deployment of this endograft may be complicated by folding and collapse of the (unsupported by a stent) aortic body or limbs, making catheterization and ballooning impossible. We present a case of Ovation endograft contralateral limb collapse in a tight AAA lumen due to thrombus deposition, which led to folding and total occlusion of the limb and made limb catheterization impossible. This is a real-life example of how the external iliac artery to internal iliac artery endograft technique may be used as a bailout procedure, converting the procedure into an aortouni-iliac graft. To our knowledge, this is the first reported bailout use of this technique in English literature which may be used in selected cases.

Intraoperative Endovascular Stent-graft Repair of a Popliteal Artery Laceration and Occlusion during Total Knee Arthroplasty.

Injury to the popliteal vessels during total knee arthroplasty is a rare but serious complication that can cause permanent loss of function. Its incidence has been reported to be on the rise with an incidence ranging from 0.03% to 0.51%. Although rare, these complications deserve attention as they may have dire consequences, with mortality reaching 7%, amputation in up to 42%, and other morbidities such as ischemic nerve injury (foot drop). We present a case of a 78-year-old female with a pulseless limb after intraoperative injury of the popliteal artery during total knee replacement surgery who was immediately investigated with digital subtraction angiography and found to have a popliteal artery laceration with significant bleeding and a distal occlusion of the artery that was repaired endovascularly. A covered stent graft was used to simultaneously exclude the arterial laceration and to recanalize the localized popliteal occlusion. To our knowledge, this is the first report of an iatrogenic popliteal artery laceration and occlusion treated endovascularly in the intraoperative time.

Graft inflow stenosis induced by the inflatable ring fixation mechanism of the Ovation stent-graft system: hemodynamic and clinical implications.

PURPOSE: To investigate the observed inflow stenosis at the O-rings of the Ovation stent-graft and evaluate its hemodynamic and clinical impact. METHODS: The study involved 49 consecutive patients (48 men; mean age 71.2 ± 7.7 years) treated successfully with the Ovation abdominal aortic stent-graft between June 2011 and January 2014 at a single center. Cross-sectional area and radius measurements of the infrarenal aorta just proximal to the sealing mechanism, as well at the site of stenosis, were measured from 3D reconstructions of the 1-month postoperative computed tomographic angiograms. Based on Poiseuille's law, the predicted pressure drop was calculated for each patient based on the length of the stenosis. Invasive blood pressure measurements at 3 levels (proximal to the inflatable rings, halfway inside the stenosis, and distal to the stenosis) were obtained in 10 patients intraoperatively. Ankle-brachial index (ABI) values preoperatively were compared to those after the procedure for all patients to assess the clinical impact of this phenomenon. RESULTS: Median internal cross-sectional area at the site of the stenosis was significantly reduced compared to the area just proximal to the O-rings [57% reduction: 123 mm(2) (range 28-254) vs. 283 mm(2) (range 177-531), respectively; p<0.001]. The same was observed for the radius [6.5 mm (range 3-9) vs. 9.5 mm (range 7.5-13), respectively; p<0.001]. Based on the median 15 mm length of the stenosis (range 13-17) observed in the study population, a median pressure drop of 0.13 mmHg (range 0-0.25) along the stenosis was calculated. Invasive blood pressure measurements indicated a non-significant pressure change along the stenosis (e.g., 0.7 mmHg between the proximal level and halfway inside the stenosis). ABI remained practically unchanged postoperatively. CONCLUSION: The advantages of the Ovation device's unique sealing mechanism come at the expense of a median area inflow stenosis of ∼ 60%. This stenosis does not cause a hemodynamically significant pressure drop. Future modification of the graft ring design may be needed in order to reduce this stenosis.

Transcatheter embolisation of iatrogenic renal vascular injuries.

PURPOSE: The aim of our study was to review our experience and long-term follow-up in the treatment of iatrogenic renal vascular injuries using transcatheter embolisation. MATERIALS AND METHODS: Our retrospective analysis of cases collected in two interventional centres consists of a total of 21 patients who underwent renal arterial embolisation (RAE) for iatrogenic arterial kidney bleeding. Biopsy (n = 4), percutaneous nephrolithotomy (n = 4), nephron-sparing surgery (n = 4), guidewire-induced arterial perforation during coronary angiography or renal stenting (n = 3), percutaneous nephrostomy (n = 3), renal endopyelotomy/pyeloplasty (n = 2) and surgical nephrectomy were the iatrogenic causes. Seven patients presented with haemodynamic instability requiring blood transfusion (33.3%), the remaining were haemodynamically stable (66.7%). Diagnostic renal angiography revealed 9 actively bleeding vessels, 6 pseudoaneurysms, 4 arteriovenous fistulas and 1 arterio-calyceal fistula. In one patient selective renal arteriography was negative probably because the bleeding observed at CT angiography was self-limited. Twenty-one embolisation procedures were performed in 20 patients; one patient required a second embolisation 3 h after the first one. Embolisation was performed with microcoils, polyvinyl alcohol particles, embospheres, spongostan emulsion and vascular plug. RESULTS: The technical success rate was 100%. The overall clinical success rate was 95%. Apart from a patient who died due to disseminated intravascular coagulation, no major complications requiring intensive care treatment were encountered during or after the procedures. No patient required emergency surgery or subsequent surgical treatment. No statistically significant differences in eGFR or renal function stage appeared after RAE. CONCLUSIONS: Percutaneous treatment can be proposed as a first-line treatment in iatrogenic renal arterial injuries, resulting in a safe and effective procedure.

Technical challenges during emergent endovascular aneurysm repair with the ALTO system.

INTRODUCTION: Ruptured abdominal aortic aneurysms (AAAs) pose an immediate threat for patient's life and endovascular repair (EVAR) is currently the preferred treatment modality in the presence of suitable anatomy. This is determined based on the requirements of each endograft as described in the instructions for use (IFU). The new ALTO system (Endologix, Irvin, CA, U.S.A.), can accommodate a great range of anatomies such as short necks and/or narrow access, but its unique design requires specific technical modifications during treatment of ruptured AAAs. AREAS COVERED: The standard double balloon technique has long been described and it is used to provide circulatory support during EVAR for ruptured AAA. While this technique is straightforward with the use of endografts with a traditional design, this would not be the case if one uses the ALTO system. In that case specific maneuvers would be required to treat AAA patients in an acute setting. EXPERT OPINION: The ALTO system although being able to treat AAAs with adverse anatomy, it may not be appropriate during treatment of ruptured AAA patients with profound hemodynamic instability. A careful evaluation of the individual's patient anatomy and hemodynamic condition is mandatory in order to decide the best endograft for each case.

Concomitant vascular and orthopedic trauma: 10 points to consider.

Although vascular injuries complicate only 1-2% of patients with orthopedic trauma, they may be encountered in a much higher rate of around 10 % in injuries around the knee and elbow joints following both fractures and dislocations. In case of vascular involvement, specific diagnostic and therapeutic challenges arise and there is a higher risk for significant morbidity (i.e. limb loss) or mortality. In the absence of randomized data, diagnostic and therapeutic algorithms are not always straightforward and clinical practice may be based on experience and local protocols rather than firm evidence. With this article we intend to review available literature regarding concomitant skeletal and vascular trauma in order to provide concise information and clear guidelines of when to operate with least investigations and when to go for a full spectrum of investigations in the absence of hard clinical signs. Additionally, other aspects concerning the manipulation of these patients are discussed, such as the indications of primary amputation, the potential role of endovascular techniques and the value of the Resuscitative Endovascular Balloon Occlusion of the Aorta. In summary, this scoping review summarizes current practices in the diagnostic and therapeutic management of patients with concomitant orthopedic and vascular injuries, discusses different treatment strategies and gives a practical perspective for implementation on every day practice.

Utility of Dual-Energy Computed Tomography in lesion characterization and treatment planning for peripheral Chronic Total Occlusions: A comprehensive analysis of crossing difficulty.

PURPOSE: To investigate whether Dual-Energy Computed Tomography (DECT) could be useful in the lesion characterization and endovascular treatment planning of symptomatic patients with peripheral arterial disease (PAD) due to Chronic Total Occlusions (CTO). MATERIALS AND METHODS: Between 2018 and 2022, 60 symptomatic patients (52 male, age 71 years) with peripheral arterial CTO underwent DECT angiography before percutaneous endovascular treatment. Patients were classified, according to guidewire crossing difficulty into four categories, which were subsequently correlated with DECT values, including Dual Energy Index (DEI) and Effective Z (Zeff). DECT values were also corelated with crossing time. The crossing difficulty was further correlated with the Trans-Atlantic Inter-Society Consensus Document (TASC II) classification. RESULTS: Technical success, defined as perceived antegrade true lumen or subintimal crossing, was achieved in 76.7 %. Among the cases, 20 were deemed easy, 14 moderate, 12 hard and 14 were failed attempts. Statistical analysis revealed a significant correlation between DEI, Zeff values, and the crossing difficulty categories (p < 0.001). Additionally, there was also a correlation between crossing time and DECT values. However, no significant correlation was recorded between difficulty categories and TASC II classification. CONCLUSION: Pre-procedural DECT angiography provides valuable information for patient selection and planning of the revascularization strategy. Moreover, it is helpful in the selection of the appropriate PTA materials, based on the lesion characteristics. Further research should be invested in this important field, to determine the optimal treatment approach in patients suffering from PAD due to CTOs.

Central venous catheters: Which, when and how.

Short-term or long-term CVCs are now considered the standard of practice for the administration of chemotherapy, fluid therapy, antibiotic therapy, and parenteral nutrition. Central venous access catheters are broadly divided into tunneled or non-tunneled catheters. Tunneled catheters can be further subdivided into totally implanted and totally not implanted devices. Device selection generally depends on various factors such as availability of peripheral veins, expected duration of therapy, and desired flow rate. Ultrasound-guided access is the safest technique for central venous access compared to the landmark technique and departments should strive to for a 100% ultrasound guided access. This review gives a basic overview of the differences of CVC catheters including PICCs, Hickman-catheters and port-catheters along with the criteria for CVC selection. It will also describe technical tips on placement of CVCs. Finally, it aims to highlight complications which are associated with CVC placement and options to treat or prevent them.