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.

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.

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.

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.

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).

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.

Contemporary (2009-2014) clinical outcomes after femoropopliteal bypass surgery for chronic limb threatening ischemia are inferior to those reported in the UK Bypass versus Angioplasty for Severe Ischaemia of the Leg (BASIL) trial (1999-2004).

BACKGROUND: Bypass surgery (BS) remains the gold standard revascularization strategy in patients with chronic limb-threatening ischemia (CLTI) owing to infrainguinal disease. The Bypass versus Angioplasty for Severe Ischaemia of the Leg (BASIL)-1 trial showed that, in patients with CLTI who survived for 2 years or more, BS resulted in better clinical outcomes. Despite this finding, there has been an increasing trend toward an endovascular-first approach to infrainguinal CLTI. Our aim was to investigate whether changes in practice have impacted the clinical outcomes of BS in our unit 10 years after BASIL-1. METHODS: Data for patients who underwent femoropopliteal (FP) BS in BASIL-1 (1999-2004) were retrieved from trial case record forms. The comparator contemporary series (CS) comprised all patients undergoing FP BS for CLTI in our unit between 2009 and 2014. Demographic and clinical outcome data on patients in the CS were collected from the prospectively collected hospital electronic notes. Anatomic patterns of disease in the BASIL-1 and CS cohorts were scored using the Bollinger and GLASS criteria. Statistical analysis was performed in SAS v9.4. RESULTS: There were 128 patients from BASIL-1 and 50 patients in the CS. Baseline age, gender, affected limb, and diabetes prevalence were similar, as were days spent in hospital out to 12 months and length of follow-up. BASIL-1 patients were more likely to be current smokers (P = .000) and had a higher creatinine (P = .04). The 30-day morbidity and mortality were higher in BASIL-1 (45.3% vs 22%; P = .004). There was no significant difference between BASIL-1 and CS with regard to run-off Bollinger (37.7 vs 32.1; P = .167) and IP GLASS (0 vs 0; P = .390) scores, with both groups having a median of two runoff vessels. Amputation-free survival (62% vs 28%; hazard ratio [HR], 1.86; 95% confidence interval [CI], 1.18-2.93; P = .007), limb salvage (85% vs 69%; HR, 2.31; 95% CI, 1.14-4.68; P = .02), overall survival (69% vs 35%; HR, 1.66; 95% CI, 1.00-2.74; P = .05) and major adverse limb events (67% vs 47%; HR, 1.93; 95% CI, 1.15-3.22; P = .01) were all significantly better in BASIL-1. CONCLUSIONS: Although 30-day mortality and morbidity were significantly lower, all of the examined longer term clinical outcomes after FP BS were significantly worse in the CS group a decade on from BASIL-1. Further research in the form of prospective cohort studies and randomized controlled trials is urgently required to determine if the CS data reported herein are generalizable to current vascular surgical practice and, if so, to determine the reasons for these unexpected outcomes.

Survival prediction in patients with chronic limb-threatening ischemia who undergo infrainguinal revascularization.

OBJECTIVE: Accurate survival prediction critically influences decision-making in caring for patients with chronic limb-threatening ischemia (CLTI). The Bypass versus Angioplasty in Severe Ischaemia of the Leg (BASIL) trial demonstrated that in patients who survived >2 years, there was a significant advantage to infrainguinal bypass compared with endovascular intervention, which increased with time. Validated survival models for patients with CLTI are lacking. METHODS: The Vascular Quality Initiative was interrogated for patients who underwent infrainguinal bypass or endovascular intervention for CLTI (January 2003-February 2017). Cox survival models were generated using only preoperative variables. Survival at 30 days, 2 years, and 5 years was modeled separately. Patients were defined as low risk (30-day survival >97% and 2-year survival >70%), medium risk (30-day survival 95%-97% or 2-year survival 50%-70%), and high-risk (30-day survival <95% or 2-year survival <50%). RESULTS: Among 38,470 unique CLTI patients, 63% (n = 24,214) underwent endovascular intervention and 37% (n = 14,256) underwent infrainguinal bypass. Kaplan-Meier estimates of overall survival at 30 days, 2 years, and 5 years were 98%, 81%, and 69%, respectively. The proportion of patients in the low-, medium-, and high-risk groups was 84%, 10%, and 6.5%, respectively. Patients in the low-risk group were significantly less likely to undergo endovascular intervention compared with those in the high-risk group (low risk, 59% endovascular; high risk, 75% endovascular; P < .0001). Independent predictors of death were similar in all three models, with greatest magnitude of effect associated with age >80 years, oxygen-dependent chronic obstructive pulmonary disease, stage 5 chronic kidney disease, and bedbound status. The C index for the 30-day model, 2-year model, and 5-year model was 0.76, 0.72, and 0.71, respectively. Procedure type (open or endovascular) was not significant in any models and did not have an impact on C indices. CONCLUSIONS: These survival prediction models, derived from a large U.S. cohort of patients who underwent revascularization for CLTI, demonstrated good performance and should be validated. Most CLTI patients considered candidates for limb salvage were of average perioperative risk and were predicted to survive beyond 2 years. These models can differentiate patients into low-, medium-, and high-risk groups to facilitate evidence-based revascularization recommendations that are consistent with current treatment guidelines.

Global vascular guidelines on the management of chronic limb-threatening ischemia.

Chronic limb-threatening ischemia (CLTI) is associated with mortality, amputation, and impaired quality of life. These Global Vascular Guidelines (GVG) are focused on definition, evaluation, and management of CLTI with the goals of improving evidence-based care and highlighting critical research needs. The term CLTI is preferred over critical limb ischemia, as the latter implies threshold values of impaired perfusion rather than a continuum. CLTI is a clinical syndrome defined by the presence of peripheral artery disease (PAD) in combination with rest pain, gangrene, or a lower limb ulceration >2 weeks duration. Venous, traumatic, embolic, and nonatherosclerotic etiologies are excluded. All patients with suspected CLTI should be referred urgently to a vascular specialist. Accurately staging the severity of limb threat is fundamental, and the Society for Vascular Surgery Threatened Limb Classification system, based on grading of Wounds, Ischemia, and foot Infection (WIfI) is endorsed. Objective hemodynamic testing, including toe pressures as the preferred measure, is required to assess CLTI. Evidence-based revascularization (EBR) hinges on three independent axes: Patient risk, Limb severity, and ANatomic complexity (PLAN). Average-risk and high-risk patients are defined by estimated procedural and 2-year all-cause mortality. The GVG proposes a new Global Anatomic Staging System (GLASS), which involves defining a preferred target artery path (TAP) and then estimating limb-based patency (LBP), resulting in three stages of complexity for intervention. The optimal revascularization strategy is also influenced by the availability of autogenous vein for open bypass surgery. Recommendations for EBR are based on best available data, pending level 1 evidence from ongoing trials. Vein bypass may be preferred for average-risk patients with advanced limb threat and high complexity disease, while those with less complex anatomy, intermediate severity limb threat, or high patient risk may be favored for endovascular intervention. All patients with CLTI should be afforded best medical therapy including the use of antithrombotic, lipid-lowering, antihypertensive, and glycemic control agents, as well as counseling on smoking cessation, diet, exercise, and preventive foot care. Following EBR, long-term limb surveillance is advised. The effectiveness of nonrevascularization therapies (eg, spinal stimulation, pneumatic compression, prostanoids, and hyperbaric oxygen) has not been established. Regenerative medicine approaches (eg, cell, gene therapies) for CLTI should be restricted to rigorously conducted randomizsed clinical trials. The GVG promotes standardization of study designs and end points for clinical trials in CLTI. The importance of multidisciplinary teams and centers of excellence for amputation prevention is stressed as a key health system initiative.

A Comparison of Clinical Outcomes Following Femoropopliteal Bypass or Plain Balloon Angioplasty with Selective Bare Metal Stenting in the Bypass Versus Angioplasty in Severe Ischaemia of the Limb (BASIL) Trial.

OBJECTIVE: To compare outcomes in patients with chronic limb threatening ischaemia (CLTI) due to femoropopliteal (FP), with or without infrapopliteal (IP), disease who underwent FP (vein or synthetic) open surgical bypass (OSB), or plain balloon angioplasty (PBA), with or without bare metal stenting (BMS), in the Bypass versus Angioplasty in Severe Ischaemia of the Limb (BASIL-1) trial. METHODS: Data were extracted from BASIL-1 case record forms. Outcomes reported include immediate technical success, freedom from major adverse limb events (FF-MALE) and further re-intervention (FF-R), amputation free survival (AFS), overall survival (OS), and limb salvage (LS). RESULTS: Patients underwent primary OSB (n = 128; 89 vein, 39 synthetic) or primary PBA (n = 183; six had BMS). Mean follow up was 46.2 and 43.6 months respectively. Patients were well matched at baseline except that PBA ± BMS patients were significantly more likely to be current smokers. There was no difference in overall or IP (runoff) Bollinger angiogram scores between groups. Immediate technical success was significantly higher for OSB (98% vs. 81%; p < .001). OSB was associated with a longer mean index hospital admission (p = .001), but there was no difference in hospital days at 12 months. FF-MALE (hazard ratio [HR] 1.51; p = .04) and FF-R (HR 1.68; p = .02) but not AFS (HR 1.18; p = .4), OS (HR 1.14; p = .5), and LS (HR 1.09; p = .8) were significantly better after OSB. CONCLUSION: Although AFS, OS, and LS were similar in the two groups, OSB was associated with significantly fewer MALE and re-interventions. So, while PBA ± BMS may be a less resource intensive (expensive) and morbid option in the short term, this appears unlikely to be the case in the longer term. Present data add further weight to the argument that, where possible, patients presenting with CLTI due to FP disease should be offered OSB as their primary revascularisation procedure.

Comparison of Immediate and Long-term Outcomes in Men and Women Undergoing Revascularisation for Chronic Limb Threatening Ischaemia in the Bypass vs. Angioplasty in Severe Ischaemia of the Leg (BASIL-1) Trial.

BACKGROUND: The reports from cohort studies comparing outcomes after revascularisation for chronic limb threatening ischaemia (CLTI) between men and women remain controversial. Anatomical and clinical disease severity is often heterogeneous, and treatment choice influenced by a variety of clinician and patient factors. The aim was to compare outcomes in men and women entered into the only randomised study comparing bypass and angioplasty for infra-inguinal disease causing severe limb ischaemia. METHODS: Data were obtained from BASIL-1 trial case record forms. Baseline demographics were compared, and Cox proportional hazard models were used to examine the relationship between sex and amputation free survival (AFS), overall survival (OS), and freedom from major adverse limb events (FF-MALE) using a per-protocol analysis. Data were analysed using a per-protocol analysis. RESULTS: A total of 452 patients were randomised into the BASIL-1 trial from 1999 to 2004. At randomisation, women were older and less likely to be smokers, to have diabetes, or to be on recommended best medical therapy. Men were more likely to present with gangrene. Ankle brachial pressure index (ABPI), post-revascularisation length of hospital stay, and 30 day morbidity and mortality were similar for men and women. At three years, female sex was associated with significantly better AFS (HR 0.65, 95% CI 0.47-0.89, p < .01), OS (HR 0.66 95% CI 0.46-0.95, p = .02) and FF-MALE (HR 0.74, 95% CI 0.57-0.96, p = .02). CONCLUSION: In the BASIL-1 trial, women had similar short term but better long term outcomes after revascularisation. Sex is an important consideration when developing early, evidence based treatment pathway and revascularisation strategies for CLTI, and is an independent risk factor for outcomes following revascularisation as well as development of symptomatic PAD.

Survival prediction in patients with chronic limb-threatening ischemia who undergo infrainguinal revascularization.

OBJECTIVE: Accurate survival prediction critically influences decision-making in caring for patients with chronic limb-threatening ischemia (CLTI). The Bypass versus Angioplasty in Severe Ischaemia of the Leg (BASIL) trial demonstrated that in patients who survived >2 years, there was a significant advantage to infrainguinal bypass compared with endovascular intervention, which increased with time. Validated survival models for patients with CLTI are lacking. METHODS: The Vascular Quality Initiative was interrogated for patients who underwent infrainguinal bypass or endovascular intervention for CLTI (January 2003-February 2017). Cox survival models were generated using only preoperative variables. Survival at 30 days, 2 years, and 5 years was modeled separately. Patients were defined as low risk (30-day survival >97% and 2-year survival >70%), medium risk (30-day survival 95%-97% or 2-year survival 50%-70%), and high-risk (30-day survival <95% or 2-year survival <50%). RESULTS: Among 38,470 unique CLTI patients, 63% (n = 24,214) underwent endovascular intervention and 37% (n = 14,256) underwent infrainguinal bypass. Kaplan-Meier estimates of overall survival at 30 days, 2 years, and 5 years were 98%, 81%, and 69%, respectively. The proportion of patients in the low-, medium-, and high-risk groups was 84%, 10%, and 6.5%, respectively. Patients in the low-risk group were significantly less likely to undergo endovascular intervention compared with those in the high-risk group (low risk, 59% endovascular; high risk, 75% endovascular; P < .0001). Independent predictors of death were similar in all three models, with greatest magnitude of effect associated with age >80 years, oxygen-dependent chronic obstructive pulmonary disease, stage 5 chronic kidney disease, and bedbound status. The C index for the 30-day model, 2-year model, and 5-year model was 0.76, 0.72, and 0.71, respectively. Procedure type (open or endovascular) was not significant in any models and did not have an impact on C indices. CONCLUSIONS: These survival prediction models, derived from a large U.S. cohort of patients who underwent revascularization for CLTI, demonstrated good performance and should be validated. Most CLTI patients considered candidates for limb salvage were of average perioperative risk and were predicted to survive beyond 2 years. These models can differentiate patients into low-, medium-, and high-risk groups to facilitate evidence-based revascularization recommendations that are consistent with current treatment guidelines.

Global Vascular Guidelines on the Management of Chronic Limb-Threatening Ischemia.

GUIDELINE SUMMARY: Chronic limb-threatening ischemia (CLTI) is associated with mortality, amputation, and impaired quality of life. These Global Vascular Guidelines (GVG) are focused on definition, evaluation, and management of CLTI with the goals of improving evidence-based care and highlighting critical research needs. The term CLTI is preferred over critical limb ischemia, as the latter implies threshold values of impaired perfusion rather than a continuum. CLTI is a clinical syndrome defined by the presence of peripheral artery disease (PAD) in combination with rest pain, gangrene, or a lower limb ulceration >2 weeks duration. Venous, traumatic, embolic, and nonatherosclerotic etiologies are excluded. All patients with suspected CLTI should be referred urgently to a vascular specialist. Accurately staging the severity of limb threat is fundamental, and the Society for Vascular Surgery Threatened Limb Classification system, based on grading of Wounds, Ischemia, and foot Infection (WIfI) is endorsed. Objective hemodynamic testing, including toe pressures as the preferred measure, is required to assess CLTI. Evidence-based revascularization (EBR) hinges on three independent axes: Patient risk, Limb severity, and ANatomic complexity (PLAN). Average-risk and high-risk patients are defined by estimated procedural and 2-year all-cause mortality. The GVG proposes a new Global Anatomic Staging System (GLASS), which involves defining a preferred target artery path (TAP) and then estimating limb-based patency (LBP), resulting in three stages of complexity for intervention. The optimal revascularization strategy is also influenced by the availability of autogenous vein for open bypass surgery. Recommendations for EBR are based on best available data, pending level 1 evidence from ongoing trials. Vein bypass may be preferred for average-risk patients with advanced limb threat and high complexity disease, while those with less complex anatomy, intermediate severity limb threat, or high patient risk may be favored for endovascular intervention. All patients with CLTI should be afforded best medical therapy including the use of antithrombotic, lipid-lowering, antihypertensive, and glycemic control agents, as well as counseling on smoking cessation, diet, exercise, and preventive foot care. Following EBR, long-term limb surveillance is advised. The effectiveness of nonrevascularization therapies (eg, spinal stimulation, pneumatic compression, prostanoids, and hyperbaric oxygen) has not been established. Regenerative medicine approaches (eg, cell, gene therapies) for CLTI should be restricted to rigorously conducted randomizsed clinical trials. The GVG promotes standardization of study designs and end points for clinical trials in CLTI. The importance of multidisciplinary teams and centers of excellence for amputation prevention is stressed as a key health system initiative.

Editor's Choice - A Comparison of Clinical Outcomes Between Primary Bypass and Secondary Bypass After Failed Plain Balloon Angioplasty in the Bypass versus Angioplasty for Severe Ischaemia of the Limb (BASIL) Trial.

OBJECTIVE: Chronic limb threatening ischaemia (CLTI) is a growing global health problem. The UK NIHR HTA funded BASIL trial is still the only randomised controlled trial to have compared a "bypass surgery first" with a "plain balloon angioplasty (PBA) first" strategy for the management of CLTI. In patients who were likely to survive for 2 years and had a suitable vein, primary bypass (PB) was associated with better clinical outcomes. Furthermore, PBA was associated with a high technical and clinical failure rate and many went on to have secondary bypass (SB). This study aimed at comparing clinical outcomes following PB and SB in the BASIL trial. METHODS: Demographic, procedural, and outcome data were obtained from the BASIL case report forms. Outcomes were amputation free survival (AFS), limb salvage (LS), overall survival (OS), and freedom from revascularisation (FFR). The SB cohort comprises patients whose first trial intervention was PBA and who subsequently underwent bypass during follow up. The PB cohort comprises those patients whose first trial intervention was bypass. RESULTS: The 190 PB and 49 SB patients were well matched except that the SB patients were more likely to be current smokers. At a median of 7 years, PB was associated with better AFS (PB 60% vs. SB 40%; HR 1.58, p = .04), LS (PB 85% vs. SB 73%, p = .06), and OS (PB 68% vs. 51%, p = .06). FFR was equivalent (PB 53% vs. 53%, p = .3). CONCLUSION: In the BASIL trial, clinical outcomes following PB were significantly better than in patients undergoing SB after failed PBA. Prior to treating patients with CLTI with primary PBA, clinicians should consider that if this should fail, the outcome of attempted subsequent bypass is likely to be significantly worse than if PB were attempted.

The Relationship Between Serum Interleukin-1α and Asymptomatic Infrarenal Abdominal Aortic Aneurysm Size, Morphology, and Growth Rates.

OBJECTIVE/BACKGROUND: In a pilot study, a relationship between abdominal aortic aneurysm (AAA) diameter and serum interleukin (IL)-1α levels was reported, and that endothelial cell (EC) activation in vitro in response to serum from patients with AAA was blocked by anti-IL-1α antibodies. The aim of the present study was to further investigate the relationship between serum IL-1α and asymptomatic infrarenal AAA size, morphology, and growth rates. METHODS: Serum IL-1α was measured using enzyme linked immunosorbent assay in 101 patients with asymptomatic, infrarenal AAA and related to aneurysm size, morphology, and growth rates. RESULTS: IL-1α was measured in 101 patients. There was no statistically significant difference in mean age between men and women. IL-1α was detectable in 62.4% of patients; median IL-1α titre was 3.26 pg/mL. There was no statistically significant relationship between IL-1α and maximum AAA antero-posterior diameter as measured by ultrasound (p = .649), AAA morphology (aortic length [p = .394], sac [p = .369], and thrombus volume [p = .629]) as measured on computed tomography, absolute increase in AAA diameter (p = .214), or AAA growth rate (p = .230). CONCLUSION: IL-1α is detectable in the majority of patients with infrarenal AAA, but the cause and clinical significance of this novel observation remains unknown.

Analysis of Effect of National Institute for Health and Care Excellence Clinical Guideline CG168 on Management of Varicose Veins in Primary Care Using the Health Improvement Network Database.

OBJECTIVE/BACKGROUND: In July 2013, new UK guidelines recommended that all patients with symptomatic varicose veins (VV) be referred to a specialist vascular service for consideration of superficial venous intervention (SVI). In the UK, general practitioners (GPs) in primary care control access to publicly funded vascular services provided through the National Health Service. GP awareness and concordance with Clinical Guideline (CG)168 recommendations is vital if patients with VV are to receive evidence-based treatment in line with national recommendations. The aim was to assess the UK-wide impact of new guidelines on GP management of VV using a large database of electronic GP records. METHODS: An eligible population of patients aged ≥ 18 years was analysed over two 18-month periods, before and after guideline publication. Those with a new diagnosis of VV in each time period were analysed in terms of demographics, specialist referral, compression hosiery prescriptions, and recorded SVI. RESULTS: Analysis included approximately two million patients from 285 GP practices. Before and after CG168 cohorts were well matched. Study populations included 13,014 patients before and 12,466 patients after guideline publication. There was an increase in specialist referrals from 24% (n = 3173) to 28% (n = 3457) (Cox hazard ratio [HR] 1.15, 95% confidence interval [CI] 1.09-1.20; p < .001). Median time to referral was 1.5 days. Prescribed compression hosiery declined from 20% (n = 2558) before the new guidelines to 18% (n = 2292) after the new guidelines (HR 0.93, 95% CI 0.88-0.98; p = .008). There were similar increases in proportions recorded as having SVI, from 3.6% (n = 469) before the new guidelines to 4.2% (n = 526) after the new guidelines (HR 1.16, 95% CI 1.02-1.31; p = .023). There was a statistically significant increase in endothermal ablation after CG168. In Cox models, age, sex, Townsend quintile, and body mass index were significantly related to the chance of referral and SVI. CONCLUSION: Encouragingly, following publication of National Institute for Health and Care Excellence CG168, there has been a statistically significant improvement in the management of VV in primary care in line with the CG recommendations.

Comparison of 2 Sample Processing Methods and 9 Commercial Immunoassays for the Detection of Interleukin-1α in the Serum of Patients with Abdominal Aortic Aneurysm.

BACKGROUND: For a cytokine to have a role as a clinically useful biomarker, it must be measureable in a practical, reliable, and reproducible manner. Furthermore, assays from different manufacturers should produce comparable results. The aim of this paper was to examine the effect of 2 sample processing methodologies and compare 9 commercially available immunoassays for their measurement of serum interleukin (IL)-1α in patients with abdominal aortic aneurysm. METHODS: Two sample processing methodologies and 9 manufacturers' immunoassays were compared. Each immunoassay was also tested for detection of both IL-1α isoforms. RESULTS: A positive signal for IL-1α was found in all serum samples, in all immunoassays, using both processing methods. In the majority, titer concentrations were unquantifiable with values below manufacturers' detectable range. Variability in titer concentrations was seen across all immunoassays. With the exception of 1 immunoassay, all were able to detect both IL-1α isoforms. CONCLUSIONS: Researchers wishing to measure serum cytokines levels should be aware that differences in sample processing methods and manufacturers' immunoassays can affect the results. This may result in misleading conclusions being drawn about biological processes underpinning a wide range of inflammatory diseases.