Editor's Choice - Bypass versus Angioplasty for Severe Ischaemia of the Leg (BASIL) Prospective Cohort Study and the Generalisability of the BASIL-2 Randomised Controlled Trial.

OBJECTIVE: The Bypass versus Angioplasty in Severe Ischaemia of the Leg-2 (BASIL-2) randomised controlled trial has shown that, for patients with chronic limb threatening ischaemia (CLTI) who require an infrapopliteal (IP) revascularisation a vein bypass (VB) first revascularisation strategy led to a 35% increased risk of major amputation or death when compared with a best endovascular treatment (BET) first revascularisation strategy. The study aims are to place the BASIL-2 trial within the context of the CLTI patient population as a whole and to investigate the generalisability of the BASIL-2 outcome data. METHODS: This was an observational, single centre prospective cohort study. Between 24 June 2014 and 31 July 2018, the BASIL Prospective Cohort Study (PCS) was performed which used BASIL-2 trial case record forms to document the characteristics, initial and subsequent management, and outcomes of 471 consecutive CLTI patients admitted to an academic vascular centre. Ethical approval was obtained, and all patients provided fully informed written consent. Follow up data were censored on 14 December 2022. RESULTS: Of the 238 patients who required an infrainguinal revascularisation, 75 (32%) had either IP bypass (39 patients) or IP BET (36 patients) outside BASIL-2. Seventeen patients were initially randomised to BASIL-2. A further three patients who did not have an IP revascularisation as their initial management were later randomised in BASIL-2. Therefore, 95/471 (20%) of patients had IP revascularisation (16% outside, 4% inside BASIL-2). Differences in amputation free survival, overall survival, and limb salvage between IP bypass and IP BET performed outside BASIL-2 were not subject to hypothesis testing due to the small sample size. Reasons for non-randomisation into the trial were numerous, but often due to anatomical and technical considerations. CONCLUSION: CLTI patients who required an IP revascularisation procedure and were subsequently randomised into BASIL-2 accounted for a small subset of the CLTI population as a whole. For a wide range of patient, limb, anatomical and operational reasons, most patients in this cohort were deemed unsuitable for randomisation in BASIL-2. The results of BASIL-2 should be interpreted in this context.

A Systematic Review Network Meta-Analysis and Meta-Regression on Surgical and Endovenous Interventions for the Treatment of Lower Limb Venous Ulcer Disease.

BACKGROUND: Venous leg ulcer (VLU) disease constitutes the most severe form of chronic venous insufficiency. We performed a network meta-analysis and meta-regression to investigate the efficacy and safety of the various available interventions in the treatment of VLU. METHODS: We conducted a systematic research corresponding to the instructions by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement for studies reporting on surgical or endovenous interventions for the treatment of VLU. Following data extraction, we performed a Bayesian network meta-analysis and meta-regression. Primary endpoints included VLU healing and recurrence. The secondary endpoint was postintervention complications. RESULTS: Seventeen studies evaluating the impact of compression monotherapy, radiofrequency ablation (RFA), endovenous laser ablation (EVLA), sclerotherapy, and saphenous vein surgery on VLU treatment, consisting of 2156 patients (2186 VLU) were included. When compared to compression monotherapy, RFA was the only treatment displaying a statistically-significant impact on ulcer healing, odds ratio (OR) 5.80 (95% credibility interval (CI): 1.08-35.07), while EVLA, RR 0.06 (95% CI: 0.00-0.57), sclerotherapy, RR 0.07 (95% CI: 0.00-0.68) and RFA, RR 0.12 (95% CI: 0.01-0.91) were the 3 interventions reducing VLU recurrence. EVLA (SUCRA, 69.65) ranked as the most efficient intervention concerning ulcer recurrence reduction. Regarding postintervention complications, EVLA was the only intervention displaying a statistically-significant increased risk compared to compression monotherapy, RR 14.3 (95% CI: 2.03-172.56). Meta-regression analysis exploring the impact of perforator treatment on VLU failed to predict healing, ß = -0.27 (95% CI: -2.55 to 1.85), recurrence, ß = -0.02 (95% CI: -2.96 to 2.75) and complication outcomes, ß = -0.089 (95% CI: -3.13 to 2.85). During sensitivity analysis, RFA and sclerotherapy failed to sustain their effects on ulcer healing and ulcer recurrence, respectively. In addition, sclerotherapy displayed statistically-significant inferior outcomes compared to both EVLA and RFA regarding ulcer recurrence. CONCLUSION: This is the first network meta-analysis examining the effect of various interventions on VLU disease. While we have demonstrated the efficacy of RFA and ELVA in ulcer recurrence prevention, our results regarding the impact of RFA and sclerotherapy on VLU healing and recurrence, respectively, should be interpreted with caution. In addition, this review raises questions concerning the value of surgery and perforator interventions in the treatment of VLU. Further research through randomized controlled trials is required. CLINICAL IMPACT: Our review has revealed the significant efficacy of endovenous laser ablation (EVLA) and radiofrequency ablation (RFA) in effectively reducing the incidence of ulcer recurrence when compared to compression monotherapy. These outcomes hold the potential to provide relevant insights to both medical practitioners and patients, thereby informing a more prudent and enlightened decision-making approach. Such informed decisions, aimed at mitigating the recurring occurrence of venous leg ulcers, carry profound significance given the considerable socioeconomic implications associated with this medical condition.

A vein bypass first versus a best endovascular treatment first revascularisation strategy for patients with chronic limb threatening ischaemia who required an infra-popliteal, with or without an additional more proximal infra-inguinal revascularisation procedure to restore limb perfusion (BASIL-2): an open-label, randomised, multicentre, phase 3 trial.

BACKGROUND: Chronic limb-threatening ischaemia is the severest manifestation of peripheral arterial disease and presents with ischaemic pain at rest or tissue loss (ulceration, gangrene, or both), or both. We compared the effectiveness of a vein bypass first with a best endovascular treatment first revascularisation strategy in terms of preventing major amputation and death in patients with chronic limb threatening ischaemia who required an infra-popliteal, with or without an additional more proximal infra-inguinal, revascularisation procedure to restore limb perfusion. METHODS: Bypass versus Angioplasty for Severe Ischaemia of the Leg (BASIL)-2 was an open-label, pragmatic, multicentre, phase 3, randomised trial done at 41 vascular surgery units in the UK (n=39), Sweden (n=1), and Denmark (n=1). Eligible patients were those who presented to hospital-based vascular surgery units with chronic limb-threatening ischaemia due to atherosclerotic disease and who required an infra-popliteal, with or without an additional more proximal infra-inguinal, revascularisation procedure to restore limb perfusion. Participants were randomly assigned (1:1) to receive either vein bypass (vein bypass group) or best endovascular treatment (best endovascular treatment group) as their first revascularisation procedure through a secure online randomisation system. Participants were excluded if they had ischaemic pain or tissue loss considered not to be primarily due to atherosclerotic peripheral artery disease. Most vein bypasses used the great saphenous vein and originated from the common or superficial femoral arteries. Most endovascular interventions comprised plain balloon angioplasty with selective use of plain or drug eluting stents. Participants were followed up for a minimum of 2 years. Data were collected locally at participating centres. In England, Wales, and Sweden, centralised databases were used to collect information on amputations and deaths. Data were analysed centrally at the Birmingham Clinical Trials Unit. The primary outcome was amputation-free survival defined as time to first major (above the ankle) amputation or death from any cause measured in the intention-to-treat population. Safety was assessed by monitoring serious adverse events up to 30-days after first revascularisation. The trial is registered with the ISRCTN registry, ISRCTN27728689. FINDINGS: Between July 22, 2014, and Nov 30, 2020, 345 participants (65 [19%] women and 280 [81%] men; median age 72·5 years [62·7-79·3]) with chronic limb-threatening ischaemia were enrolled in the trial and randomly assigned: 172 (50%) to the vein bypass group and 173 (50%) to the best endovascular treatment group. Major amputation or death occurred in 108 (63%) of 172 patients in the vein bypass group and 92 (53%) of 173 patients in the best endovascular treatment group (adjusted hazard ratio [HR] 1·35 [95% CI 1·02-1·80]; p=0·037). 91 (53%) of 172 patients in the vein bypass group and 77 (45%) of 173 patients in the best endovascular treatment group died (adjusted HR 1·37 [95% CI 1·00-1·87]). In both groups the most common causes of morbidity and death, including that occurring within 30 days of their first revascularisation, were cardiovascular (61 deaths in the vein bypass group and 49 in the best endovascular treatment group) and respiratory events (25 deaths in the vein bypass group and 23 in the best endovascular treatment group; number of cardiovascular and respiratory deaths were not mutually exclusive). INTERPRETATION: In the BASIL-2 trial, a best endovascular treatment first revascularisation strategy was associated with a better amputation-free survival, which was largely driven by fewer deaths in the best endovascular treatment group. These data suggest that more patients with chronic limb-threatening ischaemia who required an infra-popliteal, with or without an additional more proximal infra-inguinal, revascularisation procedure to restore limb perfusion should be considered for a best endovascular treatment first revascularisation strategy. FUNDING: UK National Institute of Health Research Health Technology Programme.

Surgical implementation gap: an interrupted time series analysis with interviews examining the impact of surgical trials on surgical practice in England.

OBJECTIVES: Landmark studies published near the turn of the 21st century found an implementation gap concerning the effect of evidenced-based findings on clinical practice. The current study examines the uptake of six trials that produced actionable findings to describe the effects of evidence on practice and the reasons for those effects. DESIGN: A sequential, explanatory mixed methods study was conducted. First, a quantitative study assessed whether actionable findings from large, publicly funded elective surgical trials influenced practice. Subsequently, qualitative interviews were conducted to explain the quantitative findings. SETTING: Changes in NHS-funded practice were tracked across hospitals in England. Interviews were conducted online. DATA AND PARTICIPANTS: The six surgical trials were funded and published by England's National Institute for Health Research's Health Technology Assessment programme between 2006 and 2015. Quantitative time series analyses used data about the frequencies or proportions of relevant surgical procedures conducted in England between 2001 and 2020. Subsequently, qualitative interviews were conducted with 25 participants including study authors, surgeons and other healthcare staff in the supply chain. Transcripts were coded to identify major temporal events and Consolidated Framework for Implementation Research (CFIR) domains/constructs that could influence implementation. Findings were synthesised by clinical area. RESULTS: The quantitative analyses reveal that practice changed in accordance with findings for three trials. In one trial (percutaneous vs nasogastric tube feed after stroke), the change took a decade to occur. In another (patella resurfacing), change anticipated the trial findings. In the third (abdominal aortic aneurysm repair), changes tracked the evolving evidence base. In the remaining trials (two about varicose veins and one about gastric reflux), practice did not change in line with findings. For varicose veins, the results were superseded by a further trial. For gastric reflux, surgical referrals declined as medical treatment increased. The exploratory qualitative analysis informed by CFIR found that evidence from sources apart from the trial in question was mentioned as a reason for non-adoption in the three trials where evidence did not affect practice and in the trial where uptake was delayed. There were no other consistent patterns in the qualitative data. CONCLUSION: While practice does not always change in the direction indicated by clinical trials, our results suggest that individuals, official committees and professional societies do assimilate trial evidence. Decision-makers seem to respond to the totality of evidence such that there are often plausible reasons for not adopting the evidence of any one trial in isolation.

Evaluation of the Global Limb Anatomic Staging System in patients with chronic limb-threatening ischemia undergoing endovascular intervention for femoropopliteal disease.

BACKGROUND: The Global Limb Anatomic Staging System (GLASS) is a new method of quantifying the anatomic severity of infrainguinal disease in patients with chronic limb-threatening ischemia. However, because GLASS has undergone limited validation, its value as an aid to shared decision-making regarding the choice of revascularization strategy remains incompletely defined. Here we report the relationship between GLASS and outcomes in a contemporary series comprising all 309 patients who underwent an attempt at femoropopliteal and/or infrapopiteal endovascular therapy for chronic limb-threatening ischemia in our unit between 2009 and 2014. METHODS: Baseline patient characteristics and outcome data including immediate technical success (ITS), amputation-free survival (AFS), overall survival, limb salvage, freedom from reintervention (FF-R), and freedom from major adverse limb events (FF-MALE) were obtained from hospital databases. GLASS grades and stage were obtained from pre-endovascular therapy angiographic imaging. Outcome data were censored on May 31, 2017. RESULTS: Baseline patient characteristics were similar across different GLASS femoropopliteal and IP grades and overall limb stages. Worsening GLASS stage was associated with a significant reduction in ITS (97.5% vs 91.5% vs 84.0%; P = .029). At 72 months FF-R (hazard ratio, 2.00; 95% confidence interval, 1.11-3.57; P = .020) and FF-MALE (hazard ratio, 1.76, 95% confidence interval, 1.10-2.81; P = .019) were significant worse in GLASS stage 3 than in stage 2 limbs. CONCLUSIONS: In our study, there were significant differences in ITS, FF-R and FF-MALE between limbs with GLASS stage 2 and 3 disease. However, further GLASS refinement seems likely to be required if its usefulness in everyday clinical practice as an aid to shared decision-making regarding the choice of revascularization strategy is to be maximized.

Adverse neurological events after sodium tetradecyl sulfate foam sclerotherapy - A prospective, observational study of 8056 treatments.

BACKGROUND: Ultrasound guided foam sclerotherapy (UGFS) is a flexible and highly utilised tool in the treatment of varicose veins (VVs), both as a primary treatment and as an adjunct to other treatments. Concern remains regarding the risk of neurological adverse events (AEs) such as migraine, visual disturbance and serious adverse events (SAEs) such as cerebrovascular accident that have been reported after UGFS treatments. AIM: To determine the incidence of neurological AEs and SAEs after UGFS. METHODS: A prospective, multicentre, post-authorisation safety study across Europe (both private and government) was performed between January 2015-2020. Neurological adverse events after UGFS with Fibrovein® (Sodium Tetradecyl Sulfate) 1 and 3% physician generated foam. RESULTS: 8056 patients underwent treatment. There were 46 AE (including 5 SAEs), 30 (65%) SAEs were in female patients. Mean age was 55 years with mean body mass index (BMI) of 27. Univariable logistic regression demonstrate that UGFS only treatment (i.e. no adjunctive treatment), liquid-to-gas ratio, gas type and total foam volume (1% sodium tetradecyl sulfate, STS) were significantly associated with the odds of experiencing the outcome. Multivariable logistic regression model exhibits that migraine and total foam volume (1% STS) maintained statistical significance thus associated with the odds of adverse events. CONCLUSIONS: This study demonstrates that UGFS with Fibrovein is safe with a very low incidence of neurological AEs and SAEs. Past history of migraine, use of physiological gas (O2/CO2) and increasing volumes of 1% foam increase the risk of AEs.

Procedural and 12-month in-hospital costs of primary infra-popliteal bypass surgery, infrapopliteal best endovascular treatment, and major lower limb amputation for chronic limb threatening ischemia.

OBJECTIVE: Chronic limb-threatening ischemia (CLTI) is a growing global problem due to the widespread use of tobacco and increasing prevalence of diabetes. Although the financial consequences are considerable, few studies have compared the relative cost-effectiveness of different CLTI management strategies. The Bypass vs Angioplasty in Severe Ischaemia of the Leg (BASIL)-2 trial is randomizing patients with CLTI to primary infrapopliteal (IP) vein bypass surgery (BS) or best endovascular treatment (BET) and includes a comprehensive within-trial cost-utility analysis. The aim of this study is to compare over a 12-month time horizon, the costs of primary IP BS, IP best endovascular treatment (BET), and major limb major amputation (MLLA) to inform the BASIL-2 cost-utility analysis. METHODS: We compared procedural human resource (HR) costs and total in-hospital costs for the index admission, and over the following 12-months, in 60 consecutive patients undergoing primary IP BS (n = 20), IP BET (n = 20), or MLLA (10 transfemoral and 10 transtibial) for CLTI within the BASIL prospective cohort study. RESULTS: Procedural HR costs were greatest for BS (BS £2551; 95% confidence interval [CI], £1934-£2807 vs MLLA £1130; 95% CI, £1046-£1297 vs BET £329; 95% CI, £242-£390; P < .001, Kruskal-Wallis) due to longer procedure duration and greater staff requirement. With regard to the index admission, MLLA was the most expensive due to longer hospital stay (MLLA £13,320; 95% CI, £8986-£18,616 vs BS £8714; 95% CI, £6097-£11,973 vs BET £4813; 95% CI, £3529-£6097; P < .001, Kruskal-Wallis). The total cost of the index admission and in-hospital care over the following 12 months remained least for BET (MLLA £26,327; 95% CI, £17,653-£30,458 vs BS £20,401; 95% CI, £12,071-£23,926 vs BET £12,298; 95% CI, £6961-£15,439; P < .001, Kruskal-Wallis). CONCLUSIONS: Over a 12-month time horizon, MLLA and IP BS are more expensive than IP BET in terms of procedural HR costs and total in-hospital costs. These economic data, together with quality of life data from BASIL-2, will inform the calculation of incremental cost-effectiveness ratios for different CLTI management strategies within the BASIL-2 cost-utility analysis.

Comparison of femoropopliteal plain balloon angioplasty for chronic limb-threatening ischemia in the BASIL trial and in a UK contemporary series.

BACKGROUND: Since the turn of the millennium, there has been a worldwide trend towards an endovascular-first strategy where possible revascularization strategy for chronic limb-threatening ischemia. There is concern that this may be inappropriate and can result in net patient harm. The aim of this study, therefore, is to compare important clinical outcomes following femoropopliteal plain balloon angioplasty (FP-PBA), with selective use of bare metal stents (BMSs), in a contemporary series (CS) of patients treated in our unit between 2009 and 2014 with those observed following FP-PBA ± BMS in the United Kingdom National Institute of Health Research Health Technology Assessment-funded Bypass vs Angioplasty in Severe Ischaemia of the Leg (BASIL-1 [B1]) trial (treated 1999-2004). METHODS: Baseline and clinical outcome data (amputation-free survival [AFS], overall survival [OS], limb salvage, freedom from reintervention, and freedom from major adverse limb events) were obtained from prospectively gathered hospital data and B1 trial case record forms. RESULTS: There were 237 CS and 218 B1 patients. CS patients were older (77 vs 73 years; P = .0002). B1 patients were more likely to be current smokers, less likely to be on best medical therapy, and underwent more extensive endovascular interventions. CS had more hospital admissions (4 vs 2; P < .0001) before they reached their primary endpoint (AFS). Immediate technical success was nonsignificantly higher in the CS patients (87% vs 83%; P = .2). BMS were used in 20 CS (8%) and 2 B1 (1%) patients (P = .0002). AFS (hazard ratio, 0.64; 95% confidence interval, 0.49-0.82; P = .0005) and OS (hazard ratio, 0.58; 95% confidence interval, 0.44-0.76; P = .0001) were significantly worse in the CS cohort. There was no significant difference in limb salvage, freedom from reintervention, or freedom from major adverse limb events. CONCLUSIONS: Patients with chronic limb-threatening ischemia managed in our unit (2009-2014) by means of a FP-PBA ± BMS first (where possible) revascularization strategy experienced significantly worse AFS and OS than patients treated with FP-PBA ± BMS in the B1 trial 10 years earlier (1999-2004).

A Comparison of Contemporary Clinical Outcomes Following Femoro-Popliteal Plain Balloon Angioplasty and Bypass Surgery for Chronic Limb Threatening Ischemia.

INTRODUCTION: Despite the BASIL-1 trial concluding that bypass surgery (BS) was superior to plain balloon angioplasty (PBA) in terms of longer-term amputation free (AFS) and overall survival (OS), CLTI patients are increasingly offered an endovascular-first revascularization strategy. This study investigates whether the results of BASIL-1 are still relevant to current practice by comparing femoro-popliteal (FP) BS with PBA in a series of CLTI patients treated in our unit 10 years after BASIL-1 (1999-2004). METHODS: We retrospectively analyzed prospectively gathered hospital data pertaining to 279 patients undergoing primary FP BS or PBA for CLTI in the period 2009 to 2014. We report baseline characteristics, 30-day morbidity and mortality, major adverse cardiovascular events (MACE) and long-term AFS, limb salvage (LS), OS, major adverse limb events (MALE), and freedom from re-intervention (FFR). RESULTS: 234 (84%) and 45 (16%) patients underwent PBA and BS respectively. PBA patients were significantly older (77 vs 71 years, P = 0.001) and more likely to be female (45% vs 28%, P = 0.026). Bollinger and GLASS anatomic scores were significantly more severe in the BS group. Technical success was better for BS (100% vs 87%, P = 0.007). Index hospital stay was shorter for PBA (9.1 vs 15.6 days, P = 0.035) but there was no difference in hospital days or admissions over the next 12 months. AFS (HR 1.00), LS (HR 1.44), OS (HR 0.81), MALE (HR 1.25) and FFR (HR = 1.00) were not significantly different between PBA and BS. CONCLUSION: Important clinical outcomes following FP BS and PBA for CLTI have not changed significantly in our unit in the 10 years following the BASIL-1 trial. BASIL-1 therefore remains relevant to our current practice and should inform our approach to the management of CLTI going forward.

Comparison of Clinical Outcomes in Patients Selected for Infra-Popliteal Bypass or Plain Balloon Angioplasty for Chronic Limb Threatening Ischemia Between 2009 and 2013.

INTRODUCTION: A published subgroup analysis of the Bypass versus Angioplasty in Severe Ischaemia of the Leg (BASIL)-1 trial suggests that, in patients with chronic limb threatening ischemia (CLTI) due to infra-popliteal (IP) disease, clinical outcomes are better following vein bypass surgery (BS) than after plain balloon angioplasty (PBA). The aim of the present study is to determine if clinical outcomes following IP revascularization in our unit are concordant with those found in BASIL-1. METHODS: We analyzed prospectively gathered data pertaining to 137 consecutive CLTI patients undergoing IP PBA or BS between 2009 and 2013. We compared 30-day morbidity and mortality, days in hospital (index admission and out to 12-months), amputation free survival (AFS), overall survival (OS), limb salvage (LS), and freedom from arterial re-intervention (FFR). Patient outcomes were censored on 1 February 2017, providing a minimum 3 years follow-up. RESULTS: Patients undergoing BS (73/137, 47%) tended to be younger, have less comorbidity, and were more likely to be on best medical therapy (BMT). BS patients spent more days in hospital during the index admission (median 9 vs 5, p = .003), but not out to 12 months (median 15 vs 13, NS). BS patients suffered more 30-day morbidity (36% vs 10%, p < .001), mainly due to infective complications, but not mortality (3.1% vs 6.8%, NS). AFS (p = .001) and OS (p < .001), but not LS or FFR, were better after BS. CONCLUSIONS: CLTI patients selected for revascularization by means of IP BS had better long-term outcomes in terms of AFS and OS, but not FFR or LS. Although we await the results of the BASIL-2 trial, current data support the BASIL-1 sub-group analysis which suggests that patients requiring revascularization for IP disease should have BS where possible and that PBA should usually be reserved for patients who are not suitable for BS.

Editor's Choice - Relationship Between Global Limb Anatomic Staging System (GLASS) and Clinical Outcomes Following Revascularisation for Chronic Limb Threatening Ischaemia in the Bypass Versus Angioplasty in Severe Ischaemia of the Leg (BASIL)-1 Trial.

OBJECTIVE: The Global Vascular Guideline on chronic limb threatening ischaemia (CLTI) has introduced the Global Limb Anatomic Staging System (GLASS) as a new angiographic scoring system. However, the relationship between GLASS and outcomes following revascularisation has not previously been studied. METHODS: Using pre-intervention angiograms the relationship between GLASS and immediate technical failure (ITF), amputation free survival (AFS), limb salvage (LS), overall survival (OS), and freedom from major adverse limb events (FF-MALE) was examined in 377 patients undergoing endovascular therapy (EVT, n = 213) or bypass surgery (BS, n = 164) in the Bypass versus Angioplasty in Severe Ischaemia of the Leg (BASIL)-1 trial (randomised 1999-2004). RESULTS: There was no significant difference in GLASS between cohorts. There was a significant relationship between ITF and GLASS in EVT (I 14%, II 15%, III 28%, p = .049). GLASS was significantly related to AFS (hazard ratio [HR], 1.37; 95% CI 1.01-1.85; p = .042), LS (HR 1.96; 95 % CI 1.12-3.43; p = .018), and FF-MALE (HR 1.49; 95% CI 1.04-1.87; p = .028) in the EVT cohort. In BS patients, there was no relationship between GLASS and these outcomes. FF-MALE was significantly worse after EVT than BS in GLASS II (p = .038) and III (p = .001). Among the subgroup of patients with femoropopliteal (FP) disease (BS, n = 109 or EVT, n = 159), FF-MALE was significantly higher after BS than EVT (p < .001). The superiority of BS over EVT with increasing GLASS FP grade was greater in the analysis of patients using vein grafts. CONCLUSION: In the BASIL-1 cohort, GLASS is associated with outcomes following EVT but not BS. Although further validation in contemporary CLTI cohorts is required, GLASS seems likely be useful in shared decision making and for stratifying patients in future trials.