Evagelos S. Nikolopoulos

Lower-extremity Arteriovenous Access for Haemodialysis: A Systematic Review

BACKGROUND The lower extremity is increasingly used as an access site in end-stage renal disease patients. However, reports present conflicting results, creating confusion regarding the feasibility and outcomes. Our objective is to review the available literature and analyse the patency rates and complications of various types of lower-extremity arteriovenous access. METHODS An Internet-based literature search was performed using MEDLINE to identify all published reports on lower-extremity vascular access. The analysis involved studies comprising at least 10 arteriovenous accesses with both inflow and outflow vessels in the lower extremity, and reporting on patency rates and access-related complications. The weighted mean patency rates were calculated, and the chi-square (chi(2)) test was used to evaluate the differences in the complication rates in the subgroups of patients identified. RESULTS Three main types of lower-extremity vascular access were identified: the upper thigh prosthetic, the mid-thigh prosthetic and the femoral vein transposition arteriovenous access. There are limited data on saphenous vein loop grafts, which report poor results. The weighted mean primary patency rates at 12 months were 48%, 43% and 83%, respectively. The weighted mean secondary patency rates at 12 months were 69%, 67% and 93%, respectively. Access loss as a result of infection was more common in upper thigh and mid-thigh grafts than femoral vein transposition arteriovenous access (18.40%, 18.33% vs. 1.61%; P<0.05). Ischaemic complications rates were higher in autologous than prosthetic arteriovenous access (20.97% vs. 7.18%, P<0.05). CONCLUSIONS Lower-extremity vascular access has acceptable results in terms of patency, with femoral vein transposition having better patency rates than femoral grafts. Autologous access is associated with less infective complications, however, at the expense of increased ischaemic complications rates. Further research with randomised trials is required to assess the outcomes of lower-extremity vascular access.

Early results of the Endurant endograft system in patients with friendly and hostile infrarenal abdominal aortic aneurysm anatomy

OBJECTIVE To evaluate and compare the outcome after endovascular abdominal aortic aneurysm repair (EVAR) with the newly released Endurant endograft system in patients with different aortoiliac anatomic characteristics. METHODS We conducted a prospective observational study assigning patients with infrarenal abdominal aortic aneurysm (AAA) treated with the Endurant endoprosthesis from February 2009 to March 2010. Two groups were studied, according to the presence of a friendly (group I [GI] = 43) or hostile (group II [GII] = 34) infrarenal aortoiliac anatomy. Hostile profile was defined as any (or combination) of the following measurements: 5 mm ≤ proximal neck length (Lpr) ≤ 12 mm, 60° < proximal neck angle (A°pr) ≤ 90° and 60° < any iliac axis angle (A°iliac) ≤ 90°. Primary end points included technical and clinical success, freedom from early or late secondary interventions, any type of endoleak, and aneurysm-related death. All outcome measures were calculated using the Kaplan-Meier method and the log rank test was applied for comparisons between the groups. RESULTS The mean comorbid severity scoring was higher in GII (P = .018). The mean follow-up period in GI and GII was 12.9 ± 3.9 months (± SD, range: 6.4-19.8) and 12.4 ± 4 months (range: 4.2-19.6), respectively. Two unplanned conversions to aortouniiliac configurations were required in GI. The technical success rate in GI and GII was 95.4% and 100%, respectively. The requirement for intentional occlusion of the internal iliac artery, the requirement for cross-limb technique, the necessity of troubleshooting techniques, the procedure and radiation times, the frequency of postimplantation syndrome, and mean hospital stay were significantly higher in GII (P = .028, P = .013, P = .005, P = .037, P < .001, P = .032, P = .021, respectively). Two patients of GI died in the early postoperative period (one aneurysm but not device-related death), whereas no deaths in GII were recorded, yielding an overall 30-day mortality rate of 2.3%. No type I/III endoleaks were recorded up to the end of the study. Freedom from any type of endoleak, early or late secondary interventions, and aneurysm-related death at 12 months were found in 93.2%, 87.1%, and 93.3% of GI patients; respective values for GII were 86% (P = .21), 93.4% (P = .066), and 93.4%. The clinical success rate was 82.1% and 100% at 12 months for GI and GII, respectively. CONCLUSIONS Early (12 months) results suggest similar clinical performance of the Endurant stent graft system in endovascular treatment of AAAs with friendly and hostile anatomies, however, demonstrating more intra- and perioperative adversities for the last group. Larger prospective studies or even randomized trials comparing different new generation graft models are required to evaluate the comparable long-term results and possible expansion of EVAR indications for this specific endograft in adverse anatomies.

Diagnostic Criteria and Treatment of Buerger’s Disease: A Review

Buerger’s disease is an inflammatory occlusive disorder affecting the small and medium-size arteries and veins of young, predominately male, smokers. The disorder has been identified as an autoimmune response triggered when nicotine is present. Tobacco abuse is the major contributing risk factor; however, smoking seems to be a synergistic factor rather than the cause of the disease. The traditional diagnosis of Buerger’s disease is based on 5 criteria (smoking history, onset before the age of 50 years, infrapopliteal arterial occlusive disease, either upper limb involvement or phlebitis migrans, and absence of atherosclerotic risk factors other than smoking). As there is no specific diagnostic test and an absence of positive serologic markers, confident clinical diagnosis should be made only when all these 5 criteria have been fulfilled although not universally accepted. The angiographic findings in Buerger’s disease (“corkscrew,” “spider legs,” or “tree roots”) are helpful but not pathognomonic. A wide spectrum of medical or surgical therapeutic options have been proposed; however, total abstinence from tobacco use remains the only means of stopping the disease progression. The initial management of patients with Buerger’s disease should be conservative. Because several arteries may be unaffected, claudicants should be encouraged to walk, whereas patients with “critical” ischemia should be admitted for bed rest in the hospital. Bypass grafting is seldom an option, as the location of the lesions distally leaves little to bypass because of lack of target vessels. A literature review revealed only a few series reporting vascular reconstruction (mainly femorodistal bypasses) in Buerger’s disease. Bypass patency rates were suboptimal; however, the corresponding limb salvage rates were satisfactory. A possible explanation is that patent grafts, even over a short period of time, are sufficient to allow healing of ulcers in patients with Buerger’s disease.

An overview of the hemodynamic aspects of the blood flow in the venous outflow tract of the arteriovenous fistula

Upper limb vein aneurysms complicate all types of autogenous arteriovenous fistulae (AVF) and comprise false aneurysms secondary to venipuncture trauma as well as true aneurysms, characterized by dilatation of native veins. The dilatation of a normal vein and the development of a true aneurysm are strongly influenced by local hemodynamic factors affecting the flow in the drainage venous system and are also the target of operative interventions. This review article focuses on the description of these hemodynamic aspects which all physicians involved in the management of dialysis patients should be aware of. Furthermore, it delineates their complicated interactions and also highlights their utility in clinical decision-making and therapeutic management.

Clinical Outcomes After Crossed-Limb vs. Conventional Endograft Configuration in Endovascular AAA Repair

Purpose: To report a case controlled analysis of endovascular aneurysm repair (EVAR) outcomes using the crossed-limb (CxL) endovascular configuration vs. the straight-limb configuration (SLC). Methods: From January 2007 to July 2012, 27 patients (25 men; mean age 73.7±7.2 years, range 53–82) were treated by EVAR with the CxL technique. These patients were matched anatomically with 27 patients (27 men; mean age 72.4±7.4 years, range 52–86) who underwent EVAR using the same endograft and the standard SLC within a ±6-month period. Primary outcome measures included technical and clinical success and freedom from graft limb thrombosis, any type of endoleak, early or late secondary interventions, and aneurysm-related death estimated using the Kaplan-Meier method. Results: The median follow-up periods for the CxL and SLC groups were 29.9 (range 6–54) and 33.5 (range 6–59) months, respectively (p=0.81). The technical success rate was 100% in both groups, but mean procedure times were significantly longer in the CxL group (116.3 vs. 90.7 minutes, p=0.035). Twelve intraoperative endoleaks (3 each for types Ia, Ib, II, and IV) occurred but without any difference between groups (p=0.51). One CxL group patient died in the early postoperative period (aneurysm-related) and another had an early graft limb thrombosis. One late type Ib intraoperative endoleak was recorded in the SLC group (p=0.51). For the CxL vs. SLC groups, the 1-year rates for freedom from endograft limb thrombosis (94% vs. 96%), any type of endoleak (96% vs. 96%), early or late reintervention (94% vs. 96%), and aneurysm-related death (94% vs. 96%) were not significantly different. Respective values at 36 months were 82% vs. 82%, 85% vs. 84%, 81% vs. 78%, and 83% vs. 84% (p>0.05). Clinical success rates at 12 months for the CxL and SLC groups were 91% and 100% (p>0.05), respectively, whereas at 36 months, the rates were 83% and 90% (p>0.05). Conclusion: No difference was found between the crossed-limb technique and the conventional endograft position as regards short- or midterm clinical outcomes.

Surgical or endovascular therapy of abdominal penetrating aortic ulcers and their natural history: a systematic review.

Little is known regarding the outcomes of endovascular and surgical treatment of penetrating ulcers in the abdominal aorta. The potential benefit of conservative management of asymptomatic disease is also debatable. A systematic review of the literature was undertaken to investigate these issues.

The effect of different teaching methods on final year medical students' skills in examining arteries and veins.

Undergraduate teaching of Vascular Surgery faces significant challenges because of a rapid transformation of the discipline including conventional and endovascular courses. Vascular Surgery is moving progressively further away from General Surgery (GS) towards a new multidisciplinary field incorporating new technologies. The curriculum of Greek medical schools consists of ‘‘core’’ topics and electives. However, there is no consensus nationwide in what category Vascular Surgery should be included. There are different models of undergraduate teaching in the seven Greek medical schools. The field is either taught as a ‘‘core’’ subject (one medical school), elective (three) and within the discipline of GS (three). Final year medical students taught by these different models were asked to answer a written questionnaire. Eightyfive responded. The questionnaire, based on a previous one (Campbell et al., 2002), was assessing competencies and skills in examining arteries and veins; based on this a score was developed assessing the performance of students (maximum rating 7 points). Group I, 34 students (40%) had been taught Vascular Surgery as a ‘‘core’’ topic or as elective and Group II (51 students, 60%) had been taught within the discipline of GS. Group I students performed significantly better (mean score 4.6 vs. 3.7, p1⁄4 0.02). Regarding separate answers, Group I performed significantly better in questions assessing fluency using hand held Doppler. These findings indicated that students taught the discipline either as a ‘‘core topic’’ or an elective performed significantly better than those taught within the discipline of GS and practical skills as familiarity with hand-held Doppler were almost absent in Group II. Students should be exposed to an environment with a sufficient number of vascular cases. Their learning is strongly influenced by the interest of their trainers and so the use of a hand-held Doppler could hardly be taught in a GS ward. This is especially true in countries where Vascular Surgery is a separate speciality and there are few or no vascular patients in GS wards. Vascular Surgery is a becoming separate monospeciality throughout Europe and it is time to reassess our models of undergraduate teaching.

Hybrid endografts combinations for the treatment of endoleak in endovascular abdominal aortic aneurysm repair

Hybrid endografting in endovascular abdominal aortic aneurysm repair (EVAR) is defined as the process of placing a series of two or more different types of covered stents, usually to treat a complex abdominal aortic aneurysm (AAA) or a primary or secondary endoleak. We describe the treatment of a type III, a type Ib, and a type Ia endoleak in three patients respectively, using hybrid solutions, assembling components from different manufacturers. An update of the current clinical and experimental evidence on the application of anatomically compatible, hybrid endograft systems in conventional EVAR is also provided.

A hybrid approach to salvage a failing long-standing autogenous aneurysmal fistula in a hemodialysis patient

Very few studies have addressed the repair of autogenous and prosthetic-related false arteriovenous access (AVA) aneurysms in hemodialysis patients. Surgical management of complicated AVA-related aneurysms remains the gold standard method although covered stents have recently been introduced for the exclusion of such aneurysms, offering a minimally invasive therapy. In this paper, we describe a combination of open and endovascular repair for treating an anastomotic and a puncture-site aneurysm to salvage a failing long-standing autogenous radial-cephalic fistula in the wrist. Resection of the anastomotic aneurysm and reconstruction of the anastomosis proximally was initially performed. Via the first cm of the anastomosis, a Fluency® stent graft (SG) was inserted and it successfully excluded the mid-outflow vein false aneurysm. Such hybrid therapies may be the future of AVA revisions and this trend should not be overlooked by nephrologists and vascular surgeons.

Endovascular therapy for penetrating ulcers of the infrarenal aorta

We sought to investigate the short‐ and mid‐term results of the endovascular repair of infrarenal abdominal penetrating aortic ulcers (aPAUs).