External Validation of a Prognostic Model for Survival of Patients With Abdominal Aortic Aneurysms Treated by Endovascular Aneurysm Repair.

OBJECTIVE: Current guidelines recommend diameter monitoring of small and asymptomatic abdominal aortic aneurysms (AAAs) due to the low risk of rupture. Elective AAA repair is recommended for diameters ≥ 5.5 cm in men and ≥ 5.0 cm in women. However, data supporting the efficacy of elective treatment for all patients above these thresholds are diverging. For a subgroup of patients, life expectancy might be very short, and elective AAA repair at the current threshold may not be justified. This study aimed to externally validate a predictive model for survival of patients with an asymptomatic AAA treated by endovascular aneurysm repair (EVAR). METHODS: This was a multicentre international retrospective observational cohort study. Data were collected from four European aortic centres treating patients between 2001 and 2021. The initial model included age, estimated glomerular filtration rate (eGFR), and chronic obstructive pulmonary disease (COPD) as independent predictors for survival. Model performance was measured by discrimination and calibration. RESULTS: The validation cohort included 1 500 patients with a median follow up of 65 months, during which 54.6% of the patients died. The external validation showed slightly decreased discrimination ability and signs of overfitting in model calibration. However, a high risk subgroup of patients with impaired survival rates was identified: octogenarians with eGFR < 60 OR COPD, septuagenarians with eGFR < 30, and septuagenarians with eGFR < 60 and COPD having survival rates of only 55.2% and 15.5% at five and 10 years, respectively. CONCLUSION: EVAR is a valuable treatment option for AAA, especially for patients unsuitable for open repair. Nonetheless, not all these patients will benefit from EVAR, and an individualised treatment recommendation should include considerations on life expectancy. This study provides a risk stratification to identify patients who may not benefit from EVAR using the present diameter thresholds.

Anatomical feasibility of an endovascular aortic arch repair with the NEXUS endograft in patients treated with a frozen elephant trunk procedure for aortic arch pathology.

BACKGROUND: The aim of this study was to evaluate the feasibility of an endovascular repair, using the NEXUS™ Aortic Arch Stent Graft System, in a real-world cohort of patients, treated with a Frozen Elephant Trunk (FET) procedure for pathology involving the aortic arch. RESULTS: The preoperative computed tomography angiography scans of 37 patients were retrospectively analyzed using a dedicated workstation. In total, seven patients (N = 7/37; 18.9%) were eligible for endovascular repair. This number increased to eleven patients (N = 11/37; 29.7%) if an additional relining of the distal aorta would be performed. Device suitability was 47.1% in patients (N = 8/17; 47.1%) with aortic arch aneurysm, 12.5% (N = 1/8; 12.5%) in patients with an acute Stanford type A dissection and 50% (N = 2/4; 50%) in patients with Crawford type II thoraco-abdominal aneurysm. The stent graft was not suitable for any of the two patients with chronic type B dissection (N = 0/2; 0%). In 22 patients (N = 22/37; 59.5%) an endovascular repair with this type of stent graft was not feasible due to an inadequate proximal sealing zone. There was no suitable brachiocephalic trunk landing zone in 13 patients (N = 13/37; 35.1%). There was no suitable distal landing zone distal in 14 patients (N = 14/37; 36.8%). This number decreased to ten patients (N = 10/37; 27.0%) when considering an additional relining of the distal aorta. CONCLUSIONS: Endovascular repair with the NEXUS single branch stent graft is feasible in a minority of this real-world cohort that underwent a Frozen Elephant Trunk procedure. However, the applicability of this device probably improves in cases with isolated aortic arch aneurysms.

Embolization therapy for type 2 endoleaks after endovascular aortic aneurysm repair: imaging-based predictive factors and clinical outcomes on long-term follow-up

PURPOSE: To evaluate the technical, radiological, and clinical outcomes after type 2 endoleak (T2EL) embolization in patients with a growing aneurysm sac after endovascular aortic aneurysm repair (EVAR). Additionally, to determine clinical and imaging-based factors for outcome prediction after embolization of a T2EL. METHODS: A single-institution, retrospective analysis was performed of 60 patients who underwent a T2EL embolization procedure between September 2005 and August 2016 to treat a growing aneurysm sac diameter following EVAR. The patients' electronic medical records and all available pre- and post-embolization imaging were reviewed. Statistical analysis methods included logistic regression models for binary outcomes, proportional odds models for ordinal outcomes, and linear regression models for continuous outcomes. The Kaplan-Meier method was used to estimate the overall survival probability. RESULTS: Technical, radiological, and clinical success rates after T2EL embolization were 95% (n = 57), 26.7% (n = 16), and 76.7% (n = 46), respectively. Persistent aneurysm sac expansion was found in 31 patients (51.7%). Unsharp or blurred T2EL delineation on pre-interventional computed tomography (CT) was a predictive factor for a post-embolization persistent visible endoleak and persistent growth of the aneurysm sac (P = 0.025). Median survival after T2EL embolization was 5.35 years, with no difference observed between patients with persistent sac expansion compared with patients with stable or decreased sac diameter. CONCLUSION: Progression of the aneurysm sac diameter was observed in half the study patients, despite technically successful T2EL embolization. Unsharp or blurred T2EL delineation on pre-interventional CT seemed to be an imaging-based predictor for a persistent T2EL and progressive aneurysm sac growth after embolization.

A Large-Diameter Vascular Graft Replacing Animal-Derived Sealants With an Elastomeric Polymer.

INTRODUCTION: To assess the safety and efficacy of an experimental large-diameter vascular graft externally sealed with an elastomeric polymer when used as an interposition graft in the descending aorta of sheep. METHODS: The experimental vascular grafts as well as control gelatin sealed interposition grafts were inserted into the descending aorta of juvenile sheep. The grafts were assessed by time to hemostasis and blood loss during surgery and hematology and biochemistry panels at distinct time points. Magnetic resonance imaging (MRI) was performed at 3 and at 6 mo after surgery, after which the animals were euthanized and necropsies were carried out including macroscopic and microscopic examination of the grafts, anastomoses, and distal organs. RESULTS: All animals survived the study period. There was no perceivable difference in the surgical handling of the grafts. The median intraoperative blood loss was 27.5 mL (range 10.0-125.0 mL) in the experimental group and 50.0 mL (range 10.0-75.0 mL) in the control group. The median time to hemostasis was 5.0 min (range 2.0-16.0 min) minutes in the experimental group versus 6.0 min (range 4.0-6.0 min) in the control group. MRI showed normal flow and graft patency in both groups. Healing and perianastomotic endothelialization was similar in both groups. CONCLUSIONS: The experimental graft has a similar safety and performance profile and largely comparable necropsy results, in comparison to a commonly used prosthetic vascular graft, with the experimental grafts eliciting a nonadherent external fibrous capsule as the major difference compared to the control grafts that were incorporated into the periadventitia. Survival, hemostatic sealing, and hematologic and radiologic results were comparable between the study groups.

Is silver still the Holy Grail for vascular grafts?

Vascular graft infection (VGI) remains one of the most difficult topics within the field of vascular surgery. Despite many preventive measures, infection risk remains present. Mortality and morbidity rates are high, both for peripheral and aortic VGI. Articles reporting on the treatment of VGI are often small, heterogenous or even under reported, which is especially the case for the outcome of different bypass materials that can be used for peripheral VGI. This is one of the reasons why the evidence of which type of vascular graft that should be used in the current guidelines of the European Society of Vascular surgery on the treatment of aortic graft infection is limited to Level C,Class IIa. Nowadays, many types of grafts are being used to treat VGI such as autologous veins, cryopreserved allografts, rifampicin-soaked grafts and silver coated grafts. The antimicrobial effect of silver has been translated to vascular grafts from other disciplines. Nowadays it is commercially off the shelf available and often used in the daily practice, both in the prevention as in the treatment of VGI. The aim of this review was to report on the antimicrobial working mechanism of silver, to report on possible side effects and to summarize in vitro, in vivo and clinical evidence of silver coated vascular grafts, both in the treatment and prevention of VGI.

The influence of narrow aortic bifurcation on limb graft patency: a two-center retrospective study.

BACKGROUND: Narrow aortic bifurcation (NAB) has been considered as a potential risk factor for graft limb thrombosis after endovascular aortic repair (EVAR). The aim of this study was to compare mid- and long-term outcome of EVAR in patients with NAB and standard aortic bifurcation (SAB). METHODS: Data from patients receiving EVAR were prospectively collected and retrospectively analyzed. In case of angiographic limb stenosis (>50%), additional stenting was performed. Patients with a NAB (≤20mm) were included in the NAB group, the remaining patients in the SAB group. Primary endpoints were limb thrombosis rate and technical success. RESULTS: A total of 902 patients were included; 18.3% (N.=165/902) in the NAB and 81.7% (N.=737/902) in the SAB group. Mean follow-up time was 43 months (range 0-198 months). Bilateral stenting of the aortic bifurcation was performed in 2.7% (N.=27/902), 8.5% (N.=14/165) in the NAB and 1.4% (N.=10/737) in the SAB group (P=0.001). Limb thrombosis was found in 2.8% (N.=25/902), 3.6% (N.=6/165) in the NAB and 2.6% (N.=19/737) in the SAB group (P=0.55). Technical success was 97.8%, 98.8% in the NAB and 97.6% in the SAB group (P=0.33). Device related reintervention rate was 16% (N.=144/902), 15.2% in the NAB and 16.1% in the SAB group (P=0.75). CONCLUSIONS: Standard EVAR could safely be performed in patients with NAB (≤20mm) when a low threshold for additional stenting was applied. This resulted in no significant higher incidence of limb thrombosis. Additional stent deployment did not increase the complication rate.

In situ Reconstruction with Autologous Veins for the Treatment of Infected Abdominal Endografts: Single Center Experience.

Background: Vascular graft infection is a feared complication with high mortality and morbidity rates. Complete excision with in situ repair is recommended. We report our experience with patients suffering of abdominal aortic endograft infection undergoing excision and in situ reconstruction with autologous vein. Patients and Methods: All patients who underwent excision of an abdominal aortic endograft and in situ reconstruction with autologous superficial femoral veins between April 2005 and June 2021 were retrospectively reviewed. Primary outcome measures were mortality and reinfection. Secondary outcome measure was patient morbidity. Results: Fifteen patients (14 male; 93%) were included. Twenty percent of the index procedures (N = 3) were performed at our hospital, 80% (N = 12) were referred patients. Three aorto-enteric fistulae were seen. Staphylococci and enterococci were the most common pathogens (N = 8; 53%). In two out of six patients (33%) with an endograft with suprarenal fixation, the suprarenal fixation stent was left in situ. 30-day mortality rate was 6.6% (N = 1). Median follow-up time was 12 months (range 0-85). During follow-up, no reinfection was seen. Serious morbidity was witnessed in 2 patients (sepsis due to bowel leakage (N = 1), pneumonia (N = 2), hemodialysis (N = 1)). Eventration was the most common late morbidity observed (N = 5). Conclusions: Surgical treatment of vascular abdominal endograft infection by in situ reconstruction with autologous deep vein is a challenging procedure. If a multidisciplinary approach is applied and patients are centralized in experienced centers, acceptable mortality and morbidity rates can be achieved.

Long-term outcome results after endovascular aortoiliac aneurysm repair with the bifurcated EXCLUDER Endoprosthesis.

OBJECTIVE: To report the long-term outcome of patients presenting with an aortic, aortoiliac, or isolated common iliac aneurysm treated with the bifurcated EXCLUDER Endoprosthesis. Furthermore, potential differences in late outcome results between the original- and low-permeability endoprosthesis were analyzed. METHODS: A retrospective analysis of prospectively collected data of 182 patients who underwent endovascular aneurysm repair with the EXCLUDER Endoprosthesis between June 1998 and October 2015 in an academic, tertiary care center for aortic disease was performed. Patient follow-up was from 3 to 20 years (mean follow-up of 6.9 years). Primary end points were overall survival and reintervention-free survival. Secondary end points were device-related complications, endoleaks, and reinterventions. RESULTS: Overall survival at 5, 10, and 15 years was 72.8%, 42.1%, and 12.2%, respectively, with no aneurysm-related mortality and no difference in overall survival between the original- vs low-permeability endoprosthesis group (P = .617). Freedom from type I endoleak at 5 years was 94.8%. No new type I endoleak was detected beyond the 5-year follow-up mark. No type III endoleak was identified. Reintervention-free survival was 83.6%, 66.7%, and 66.7% at 5-, 10-, and 15-year follow-up, respectively. There was a significant difference in intervention-free survival between the original- vs low-permeability endoprosthesis group (P = .029) and after the 5-year follow-up mark. In addition, patients with the low-permeability endoprosthesis showed significantly fewer device-related complications (P = .002) and endoleaks (P = .005). CONCLUSIONS: Endovascular aneurysm repair using the EXCLUDER Endoprosthesis is effective and durable on long-term follow-up, with acceptably low device-related complications and reinterventions. The low-permeability endoprosthesis was associated with significantly fewer new device-related complications and endoleaks after 5 years of follow-up.

Vascular Graft Infections With Candida: A Factor for Increased Mortality in in-situ Reconstructions.

BACKGROUND: The empiric antibiotic regimen started after deep cultures and explantation of the graft mostly do not cover antifungals. We retrospectively studied the outcome of candida compared to non-candida VGI and assessed whether these results could justify the addition of antifungals to the empiric antibiotics in the early postoperative period. METHODS: All patients treated for infected aorto(ilio)femoral graft with excision and reconstruction at the vascular department of University Hospitals Leuven between January 2010 and 2017 (n = 56) were studied retrospectively. Patients were allocated to the candida group (n = 10) or non-candida group (n = 46) according to the presence of Candida in deep culture isolates. RESULTS: All-cause mortality was significantly higher in the candida group compared to the non-candida group. All-cause 30-day mortality was 40% and 13% for both groups respectively (P = 0.066). At 5 years this was 90% and 46% respectively (P = 0.014). In the candida group 6 patients (60%) had to be revised in the operating room due to bleeding, compared to 5 patients (11%) in the non-candida group (P = 0.002).  Two patients (20%) and 5 patients (11%) had to be readmitted to the ICU, respectively. CONCLUSION: Survival of candida related VGI is significantly worse, especially in the first 5 postoperative months. This could justify the addition of an antifungal to the early empiric postoperative antibiotic cocktail, especially in patients with an aorto-enteric fistula. A cost-benefit analysis could be useful to evaluate the yield.

Clinical Studies Reporting on Vascular Graft Coatings for the Prevention of Aortic Graft Infection: A Systematic Review and Meta-Analysis.

OBJECTIVE: The aim of this study was to investigate the efficacy of vascular graft coatings used in the aortic position to prevent vascular graft infection (VGI). METHODS: A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines using a pre-registered protocol (CRD42020206436). Eligible studies used a vascular graft coating in the aortic position and reported on VGI. A search was performed in MEDLINE (PubMed), Embase, Web of Science, and the Cochrane Library. Primary outcome parameters were VGI, patency, and mortality. Pooled estimates of VGI were calculated using odds ratio (OR) and 95% confidence intervals (CIs) wherever possible. Quality assessment was performed with the Newcastle-Ottawa Assessment Scale and the Revised Cochrane risk of bias tool for randomised trials. RESULTS: In total, 6 873 papers were identified. Only eight studies were included. Six of eight studies (75%) reported on known antimicrobial coating strategies such as antibiotics (n = 3) and silver (n = 3). In the other two studies, polymer coated grafts were used. Only three of eight studies compared coated with uncoated grafts (two antibiotic and one silver). Two randomised controlled trials reported on the effect of rifampicin soaked (1 mg/mL) grafts and showed no significant effect in the early (2 months; OR 0.69, 95% CI 0.29 - 1.62) or late (2 years; OR 0.73, 95% CI 0.23 - 2.32) post-operative periods. A retrospective cohort study focusing on the effect of silver coated grafts did not reveal any advantage (OR 0.19, 95% CI 0.02 - 1.64). Two polymer coated grafts were not considered to have a potential benefit in the prevention of VGIs. CONCLUSION: Clinical studies reporting on the antibacterial effect of vascular graft coatings in the aortic position to prevent VGI are scarce. For silver and antibiotic coatings, no significant protection for VGI was observed. New types of grafts or long acting coating strategies are mandatory to prevent this complication in the future.

Pre-clinical In Vitro Models of Vascular Graft Coating in the Prevention of Vascular Graft Infection: A Systematic Review.

OBJECTIVE: Vascular graft infection (VGI) is a feared complication. Prevention is of the utmost importance and vascular graft coatings (VGCs) could offer a potential to do this, with in vitro research a first crucial step. The aim of this study was to summarise key features of in vitro models investigating coating strategies to prevent VGI in order to provide guidance for the setup of future translational research. DATA SOURCES: A comprehensive search was performed in MEDLINE, Embase, and Web of Science. METHODS: A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. For each database, a specific search strategy was developed. Quality was assessed with the Toxicological data Reliability Assessment Tool (ToxRTool). In vitro models using a VGC and inoculation of the graft with a pathogen were included. The type of graft, coating, and pathogen were summarised. The outcome assessment in each study was evaluated. RESULTS: In total, 4 667 studies were identified, of which 45 papers met the inclusion criteria. The majority used polyester grafts (68.2%). Thirty-one studies (68.9%) included antibiotics, and nine studies (20%) used a commercial silver graft in their protocol. New antibacterial strategies (e.g., proteolytic enzymes) were investigated. A variety of testing methods was found and focused mainly on bacterial adherence, coating adherence and dilution, biofilm formation, and cytotoxicity. Ninety-three per cent of the studies (n = 41) were considered unreliable. CONCLUSION: Polyester is the preferred type of graft to coat on. The majority of coating studies are based on antibiotics; however, new coating strategies (e.g., antibiofilm coating) are coming. Many in vitro setups are available. In vitro studies have great potential, they can limit the use, but cannot replace in vivo studies completely. This paper can be used as a guidance document for future in vitro research.

A Five-Year Computed Tomography Follow-up Study of Proximal Aortic Neck Dilatation After Endovascular Aortic Repair Using Four Contemporary Types of Endograft.

OBJECTIVE: This study analysed the progression of proximal aortic neck diameter in patients with asymptomatic abdominal aortic aneurysms, treated by endovascular aortic repair using four different, contemporary types of endograft. METHODS: This is a retrospective study of four cohorts of 30 patients presenting with asymptomatic abdominal aortic aneurysms and treated with endovascular aortic repair using four different types of contemporary endografts, namely Endurant® (Medtronic), Excluder® (W.L. Gore), Zenith® (Cook Medical) and Ovation® (Endologix) endografts. Patients' demographics and aortic aneurysm measurements, including suprarenal aortic, proximal infrarenal neck and maximum aortic aneurysmal diameter, were gathered from the patients' electronic medical records, pre- and post-interventional computed tomography studies, respectively. Diameter measurements were modelled as a function of endograft type; an interaction test was used to test whether the evolutions over time were different between the four types of endograft. RESULTS: Suprarenal aortic diameter increased over time (P = 0.0235) and maximum aortic aneurysm diameter decreased over time (P = 0.0008) in the four types of endograft. The progressive increase in proximal neck diameter from preoperative baseline up to five years of follow-up was 1.20 mm for Endurant (P = 0.0054), 1.72 mm for Ovation (P = 0.0006), 1.14 mm for Excluder (P = 0.0102) and 2.83 mm for Zenith (P < 0.0001), respectively. Five patients (4%) presented with a late-type 1a endoleak: Endurant (n = 1); Ovation (n = 2) and Zenith (n = 2). CONCLUSION: All endografts were associated with a progressive dilatation of the proximal aortic neck over a time interval of five years and may be associated with late-type 1a endoleak.

A systematic review of preclinical data regarding commercial silver-coated vascular grafts.

OBJECTIVE: Vascular graft infection (VGI) is a serious complication with high mortality and morbidity rates. Several measures could be taken to decrease this risk, including the use of silver-containing vascular grafts. However, to date, no clinical advantages have been reported. This study reviews the outcome of preclinical studies focusing on the role of commercially available silver-coated grafts in the prevention of VGI. METHODS: A systematic review was performed with a focus on the preclinical role of commercially available silver-coated vascular grafts in the prevention and treatment of VGI. A comprehensive search was conducted in Medline, Embase, and Web of Science. RESULTS: Nine in vitro and five in vivo studies were included. Two commercial grafts were used (INTERGARD SILVER and Silver Graft). In vitro studies used both gram-positive and gram-negative strains. A positive antimicrobial effect was observed in seven of nine studies (77.8%). A delayed antifungal effect against Candida species was observed in vitro, but disappeared when adding serum proteins. In vivo studies witnessed a microbicidal effect in two out of five studies (40%), but only tested a single causative pathogen (ie, Staphylococcus aureus). CONCLUSIONS: Both in vitro and in vivo studies demonstrated conflicting and mixed results concerning the antimicrobial efficacy of commercially available silver-containing grafts in the prevention of VGI. In general, the study setup was heterogeneous in the different articles. Given the lack of convincing preclinical evidence and their poor performance in clinical studies, more data are needed at this time to guide the appropriate use of silver grafts.

Limb Occlusion Rate after EVAR With Individualized Graft Limb Selection and a Liberal Protocol of Primary Relining.

BACKGROUND: This study analyses limb occlusion rates after endovascular aneurysm repair (EVAR) with a strategy including stent-graft limb selection and liberal primary stenting (relining) in anatomies at higher risk for occlusion with uncovered self-expandable or balloon-expandable stents. METHODS: All patients undergoing elective EVAR with a bifurcated stent-graft between January 2010-August 2018 were included. A protocol involving personalized stent-graft selection and liberal primary relining based on preoperative imaging was followed during the whole period. Primary endpoints were technical success and primary limb patency during follow-up. Secondary endpoints included mortality and limb reintervention rates. Risk factors associated to limb patency and reintervention rates were analyzed. RESULTS: Six hundred and fifteen patients (548 males; mean age 72.9 ± 9 years) were included. Overall technical success was 98.5% (606/615). One (0.16%) patient died during the first 30 days. Of the 1230 limbs, 96 (8%) were deemed at risk for occlusion in view of the anatomy, and primarily relined in 62 patients. Estimated primary limb patency at 6 months, 1 year and 3 years was 99.5 ± 0.2%, 99.2 ± 0.3% and 98.5 ± 0.5%, respectively. Freedom from limb-related reintervention at 6 months, 1 year and 3 years was 98.1 ± 0.4%, 97.4 ± 0.5% and 95.6 ± 0.7%, respectively. Only one (1%) of the 96 relined limbs occluded during follow-up. No differences were found in terms of patency or freedom from reintervention between limbs at risk that were primary stented and limbs without adjunctive stents. Gore Excluder stent-grafts presented better patency (Breslow P = 0.005) and lower reintervention rates (Breslow P = 0.001) than other devices during follow-up. Peripheral artery disease was also a risk factor for reintervention (Breslow P = 0.015). CONCLUSION: Liberal use of primary limb relining in patients with iliac anatomy at higher risk for occlusion appears to be a safe and effective strategy to preserve limb patency after EVAR. Gore Excluder graft limbs present better patency and lower reintervention rates than other stent-graft types.

Pre-clinical in vivo Models of Vascular Graft Coating in the Prevention of Vascular Graft Infection: A Systematic Review.

OBJECTIVE: Vascular graft infection (VGI) remains an important complication with a high mortality and morbidity rate. Currently, studies focusing on the role of vascular graft coatings in the prevention of VGI are scarce. Therefore, the aims of this study were to survey and summarise key features of pre-clinical in vivo models that have been used to investigate coating strategies to prevent VGI and to set up an ideal model that can be used in future preclinical research. DATA SOURCES: A systematic review was conducted in accordance with the Preferred reporting items for Systematic Reviews and Meta-Analysis guidelines. A comprehensive search was performed in MEDLINE (PubMed), Embase, and Web of Science. REVIEW METHODS: For each database, a specific search strategy was developed. Quality was assessed with the Toxicological data Reliability Assessment Tool (ToxRTool). The type of animal model, graft, coating, and pathogen were summarised. The outcome assessment in each study was evaluated. RESULTS: In total, 4 667 studies were identified, of which 94 papers focusing on in vivo testing were included. Staphylococcus aureus was the organism most used (n = 65; 67.7%). Most of the graft types were polyester grafts. Rifampicin was the most frequently used antibiotic coating (n = 43, 48.3%). In the outcome assessment, most studies mentioned colony forming unit count (n = 88; 91.7%) and clinical outcome (n = 72; 75%). According to the ToxRTool, 21 (22.3%, n = 21/94) studies were considered to be not reliable. CONCLUSION: Currently published in vivo models are very miscellaneous. More attention should be paid to the methodology of these pre-clinical reports when transferring novel graft coatings into clinical practice. Variables used in pre-clinical reports (bacterial strain, duration of activity coating) do not correspond well to current clinical studies. Based on the results of this review, a proposal for a complete and comprehensive set up for pre-clinical invivo testing of anti-infectious properties of vascular graft coatings was defined.