Patient Perceptions of Surveillance of Small Abdominal Aortic Aneurysms in the Over 85s.

BACKGROUND: Recently instigated local practice for patients with small abdominal aortic aneurysms (AAAs) involves contacting all patients, aged ≥85 years, to discuss with them the advantages and disadvantages of removal from surveillance. However, reasons why patients opt to remain on, or come off, surveillance, are currently unknown. The present study's objective is to explore patient perception of surveillance decision-making. METHODS: A mixed-methods exploratory evaluation was undertaken using patient feedback obtained from a telephone survey. All patients aged ≥85 years, who had a consultation regarding ongoing surveillance of small AAAs (30-49 mm), and consented, were contacted by researchers, who conducted semi-structured interviews concerning factors influencing decision-making. RESULTS: A total of 24 patients (20 male; mean age = 86.9 years) were interviewed; 16 of 24 (66%) had opted to remain on surveillance, with no age difference between those opting in or out. Most felt surveillance was important (91%), and that it made them feel safer (73%). The majority (73%) thought they knew what happened when their AAA reached threshold (5.5 cm), what happened when a threshold AAA is not fixed (64%), and how major AAA surgery is (59%). However, actual knowledge was poor: most (91%) correctly understood surgery was major, but 56% thought that threshold AAA meant certain death or rupture; and 38% thought immediate surgery was required. Thematic analysis expounded patients' beliefs regarding surveillance, which were summarized in 3 distinct subgroups: reliance on professionals' opinions, needing peace of mind, and poor understanding. CONCLUSIONS: While most patients find surveillance reassuring, patient knowledge of AAA management at threshold is poor, potentially impacting surveillance decision-making. Elderly patients, with small AAAs contemplating ongoing surveillance, need to be better informed about AAA management at threshold to support shared decision-making.

The incidence of surgical site infection following major lower limb amputation: A systematic review.

Surgical site infections (SSIs) following major lower limb amputation (MLLA) in vascular patients are a major source of morbidity. The objective of this systematic review was to determine the incidence of SSI following MLLA in vascular patients. This review was prospectively registered with the International Prospective Register of Systematic Reviews (CRD42023460645). Databases were searched without date restriction using a pre-defined search strategy. The search identified 1427 articles. Four RCTs and 21 observational studies, reporting on 50 370 MLLAs, were included. Overall SSI incidence per MLLA incision was 7.2% (3628/50370). The incidence of SSI in patients undergoing through-knee amputation (12.9%) and below-knee amputation (7.5%) was higher than the incidence of SSI in patients undergoing above-knee amputation, (3.9%), p < 0.001. The incidence of SSI in studies focusing on patients with peripheral arterial disease (PAD), diabetes or including patients with both was 8.9%, 6.8% and 7.2%, respectively. SSI is a common complication following MLLA in vascular patients. There is a higher incidence of SSI associated with more distal amputation levels. The reported SSI incidence is similar between patients with underlying PAD and diabetes. Further studies are needed to understand the exact incidence of SSI in vascular patients and the factors which influence this.

Controlling the controls: what is negative pressure wound therapy compared to in clinical trials?

AIM: Surgical site infections (SSIs) are common following colorectal operations. Clinical trials suggest that closed incision negative pressure wound therapy (ciNPWT) may reduce SSIs compared to a 'standard of care' group. However, wound management in the standard of care group may vary. The aim of this review was to assess the control arms in trials of ciNPWT for potential confounding variables that could influence the rates of SSI and therefore the trial outcomes. METHODS: A mapping review of the PubMed database was undertaken in the English language for randomized controlled trials that assessed, in closed surgical wounds, the use of ciNPWT compared to standard of care with SSI as an outcome. Data regarding wound care to assess potential confounding factors that may influence SSI rates were compared between the ciNPWT and standard of care groups. Included were the method of wound closure, control dressing type, frequency of dressing changes and postoperative wound care (washing). RESULTS: Twenty-seven trials were included in the mapping review. There was heterogeneity in ciNPWT duration. There was little control in the comparator standard of care groups with a variety of wound closure techniques and different control dressings used. Overall standard of care dressings were changed more frequently than the ciNPWT dressing and there was no control over wound care or washing. No standard for 'standard of care' was apparent. CONCLUSION: In randomized trials assessing the intervention of ciNPWT compared to standard of care there was considerable heterogeneity in the comparator groups and no standard of care was apparent. Heterogeneity in dressing protocols for standard of care groups could introduce potential confounders impacting SSI rates. There is a need to standardize care in ciNPWT trials to assess potential meaningful differences in SSI prevention.

Clinical Effects of Tourniquet Use for Nontraumatic Major Lower Limb Amputation: A Two-Center Retrospective Cohort Study.

BACKGROUND: To investigate the effect of tourniquet use on outcomes after major lower limb amputation (MLLA) due to peripheral arterial disease or complications from diabetes mellitus. METHODS: In this 2-center retrospective observational study, vascular patients who underwent MLLA between January 1, 2016 and December 31, 2020 at 2 UK hospitals were identified using operating theater databases. Hospital databases were used to access medical records, operation notes, and laboratory reports. The use of a tourniquet in each MLLA was noted. The primary outcome was postoperative hemoglobin (Hb) drop (g/L). Secondary outcomes were units of allogeneic blood transfused perioperatively, 90-day revision rates, 90-day wound breakdown rates, surgical site infection (SSI) rates (at 30 days), and 90-day mortality. A follow-up index (a measure of follow-up completeness) was calculated for all 30-day and 90-day outcomes. RESULTS: Four hundred seventy two patients underwent MLLA, of which 124 had a tourniquet applied. The median postoperative Hb drop was significantly lower in the tourniquet group compared to the nontourniquet group (13 [interquartile range 5-22] g/L vs. 20 [interquartile range 11-28] g/L; P ≤ 0.001). Thirty three point one percent (41) of tourniquet patients received a blood transfusion perioperatively, compared to 35.6% (124) of nontourniquet patients (P = 0.82). Sixteen percent (76) of patients required surgical revision within 90 days, with no significant difference between the tourniquet and nontourniquet group (20.2% tourniquet vs. 14.7% no tourniquet; P = 0.15). SSI rates (12.0% tourniquet vs. 10.6% no tourniquet, P = 0.66) and 90-day mortality (6.5% tourniquet vs. 10.1% no tourniquet; P = 0.23) were similar. Multivariable regression demonstrated that tourniquet use was independently associated with a reduced hemoglobin drop (ß = -4.671, 95% confidence interval -7.51 to -1.83, P ≤ 0.001) but was not associated with wound breakdown, revision surgery, or SSI. Hypertension, SSI, and below-knee amputation using the skew flap technique were all significant predictors of revision surgery. All follow-up indices were ≥ 0.97. CONCLUSIONS: Tourniquet use in MLLA was associated with a significantly lower fall in postoperative Hb without evidence of harm in terms of SSI, wound breakdown/revision rates, or mortality.

Impact of closed-incision negative pressure wound dressings on surgical site infection following groin incisions in vascular surgery; a single-centre experience.

OBJECTIVES: Surgical site infection (SSI) is a common complication in vascular surgery, and is associated with increased patient morbidity, readmission and reintervention. The aim of this study was to assess the impact of closed-incision negative pressure wound therapy (CiNPWT) upon rate of SSI and length of hospital stay. METHODS: This study was reported in line with the STROBE guidelines. We assessed the baseline incidence of SSI from a 12-month retrospective cohort and, following a change in practice intervention with CiNPWT, compared to a 6-month prospective cohort. The primary endpoint was incidence of SSI (according to CDC-NHSN guidelines) while secondary endpoints included length of hospital stay, readmission, reintervention and Days Alive and Out of Hospital (DAOH) to 90-days. RESULTS: A total of 127 groin incisions were performed: 76 (65 patients) within the retrospective analysis and 51 (42 patients) within the prospective analysis (of whom 69% received CiNPWT). The primary endpoint of SSI was seen in 21.1% of the retrospective cohort and 9.8% of the prospective cohort (p = .099). Readmission was found to be significantly associated with the retrospective cohort (p = .016) while total admission (inclusive of re-admission) was significantly longer in those in the retrospective cohort (p = .013). DAOH-90 was 83 days (77-85) following introduction of the CiNPWT protocol as compared to the retrospective cohort (77 days (64-83), p = .04). CONCLUSION: Introduction of CiNPWT was associated with a reduced length of hospital stay and improved DAOH-90. Further trials on CINPWT should include patient-centred outcomes and healthcare cost analysis.

Short-term risk prediction after major lower limb amputation: PERCEIVE study.

BACKGROUND: The accuracy with which healthcare professionals (HCPs) and risk prediction tools predict outcomes after major lower limb amputation (MLLA) is uncertain. The aim of this study was to evaluate the accuracy of predicting short-term (30 days after MLLA) mortality, morbidity, and revisional surgery. METHODS: The PERCEIVE (PrEdiction of Risk and Communication of outcomE following major lower limb amputation: a collaboratIVE) study was launched on 1 October 2020. It was an international multicentre study, including adults undergoing MLLA for complications of peripheral arterial disease and/or diabetes. Preoperative predictions of 30-day mortality, morbidity, and MLLA revision by surgeons and anaesthetists were recorded. Probabilities from relevant risk prediction tools were calculated. Evaluation of accuracy included measures of discrimination, calibration, and overall performance. RESULTS: Some 537 patients were included. HCPs had acceptable discrimination in predicting mortality (931 predictions; C-statistic 0.758) and MLLA revision (565 predictions; C-statistic 0.756), but were poor at predicting morbidity (980 predictions; C-statistic 0.616). They overpredicted the risk of all outcomes. All except three risk prediction tools had worse discrimination than HCPs for predicting mortality (C-statistics 0.789, 0.774, and 0.773); two of these significantly overestimated the risk compared with HCPs. SORT version 2 (the only tool incorporating HCP predictions) demonstrated better calibration and overall performance (Brier score 0.082) than HCPs. Tools predicting morbidity and MLLA revision had poor discrimination (C-statistics 0.520 and 0.679). CONCLUSION: Clinicians predicted mortality and MLLA revision well, but predicted morbidity poorly. They overestimated the risk of mortality, morbidity, and MLLA revision. Most short-term risk prediction tools had poorer discrimination or calibration than HCPs. The best method of predicting mortality was a statistical tool that incorporated HCP estimation.

Editor's Choice - Systematic Review and Narrative Synthesis of Randomised Controlled Trials Supporting Implantable Devices for Vascular and Endovascular Procedures.

OBJECTIVE: To identify implantable devices currently used for vascular and endovascular procedures, to ascertain how many have randomised controlled trial (RCT) evidence available, and to assess the quality of that evidence. DATA SOURCES: MEDLINE, Embase, DARE, PROSPERO, clinical trial registries, and Cochrane databases. REVIEW METHODS: A list of current devices used in both vascular and endovascular procedures was generated by searching conference proceedings, manufacturer catalogues, and websites. MEDLINE, Embase, DARE, PROSPERO, clinical trial registries, and Cochrane databases were searched from inception up to June 2020. The primary outcome was the availability of RCTs to support the use of a vascular implantable device. RCTs were then quality assessed using the Cochrane risk of bias tool. RESULTS: A total of 116 current vascular implantable devices were identified. The systematic literature review identified 165 RCTs. Eighty-three of the RCTs (50.3%) applied to 33 of the 116 (28.4%) current implantable devices. When grouped by device type, eight of the 13 types (62%) had at least one RCT performed. There was a high risk of bias across the majority of the RCTs, with only nine (5.4%) deemed to be at low risk of bias. Only 22 (13.3%) RCTs had a clear safety outcome. CONCLUSION: Sixty-two per cent of implantable device types for use in vascular and endovascular interventions had at least one RCT available to show equivalence to previous devices or safety. RCTs were generally of low quality and are decreasing in frequency with time. With medical implantable device failure being increasingly recognised as causing significant harm to patients worldwide, there is a clear need for a more robust implantable device regulation and approval systems.

Antithrombotic Therapy for Aortic Aneurysms: A Systematic Review and Meta-Analysis.

OBJECTIVES: The role of antithrombotic therapy in the management of aortic and peripheral aneurysms is unclear. This systematic review and meta-analysis aimed to assess the impact of antithrombotics on clinical outcomes for aortic and peripheral aneurysms. METHODS: Medline, Embase, and CENTRAL databases were searched. Randomised controlled trials and observational studies investigating the effect of antithrombotic therapy on clinical outcomes for patients with any aortic or peripheral artery aneurysm were included. RESULTS: Fifty-nine studies (28 with antiplatelet agents, 12 anticoagulants, two intra-operative heparin, and 16 any antithrombotic agent) involving 122 102 patients were included. Abdominal aortic aneurysm (AAA) growth rate was not significantly associated with the use of antiplatelet therapy (SMD -0.36 mm/year; 95% CI -0.75 - 0.02; p = .060; GRADE certainty: very low). Antithrombotics were associated with increased 30 day mortality for patients with AAAs undergoing intervention (OR 2.30; 95% CI 1.51 - 3.51; p < .001; GRADE certainty: low). Following intervention, antiplatelet therapy was associated with reduced long term all cause mortality (HR 0.84; 95% CI 0.76 - 0.92; p < .001; GRADE certainty: moderate), whilst anticoagulants were associated with increased all cause mortality (HR 1.64; 95% CI 1.14 - 2.37; p = .008; GRADE certainty: very low), endoleak within three years (OR 1.99; 95% CI 1.10 - 3.60; p = .020; I2 = 60%; GRADE certainty: very low), and an increased re-intervention rate at one year (OR 3.25; 95% CI 1.82 - 5.82; p < .001; I2 = 35%; GRADE certainty: moderate). Five studies examined antithrombotic therapy for popliteal aneurysms. Meta-analysis was not possible due to heterogeneity. CONCLUSIONS: There was a lack of high quality data examining antithrombotic therapy for patients with aneurysms. Antiplatelet therapy was associated with a reduction in post-intervention all cause mortality for AAA, whilst anticoagulants were associated with an increased risk of all cause mortality, endoleak, and re-intervention. Large, well designed trials are still required to determine the therapeutic benefits of antithrombotic agents in this setting.

Groin Wound Infection after Vascular Exposure (GIVE) Risk Prediction Models: Development, Internal Validation, and Comparison with Existing Risk Prediction Models Identified in a Systematic Literature Review.

OBJECTIVE: This study aimed to develop and internally validate risk prediction models for predicting groin wound surgical site infections (SSIs) following arterial intervention and to evaluate the utility of existing risk prediction models for this outcome. METHODS: Data from the Groin wound Infection after Vascular Exposure (GIVE) multicentre cohort study were used. The GIVE study prospectively enrolled 1 039 consecutive patients undergoing an arterial procedure through 1 339 groin incisions. An overall SSI rate of 8.6% per groin incision, and a deep/organ space SSI rate of 3.8%, were reported. Eight independent predictors of all SSIs, and four independent predictors of deep/organ space SSIs were included in the development and internal validation of two risk prediction models. A systematic search of the literature was conducted to identify relevant risk prediction models for their evaluation. RESULTS: The "GIVE SSI risk prediction model" ("GIVE SSI model") and the "GIVE deep/organ space SSI risk prediction model" ("deep SSI model") had adequate discrimination (C statistic 0.735 and 0.720, respectively). Three other groin incision SSI risk prediction models were identified; both GIVE risk prediction models significantly outperformed these other risk models in this cohort (C statistic 0.618 - 0.629; p < .050 for inferior discrimination in all cases). CONCLUSION: Two models were created and internally validated that performed acceptably in predicting "all" and "deep" groin SSIs, outperforming current existing risk prediction models in this cohort. Future studies should aim to externally validate the GIVE models.

Systematic Review and Meta-Analysis of the Effect of Perineural Catheters in Major Lower Limb Amputations.

OBJECTIVE: Controlling pain after major lower limb amputation (MLLA) is of critical importance to patients and clinicians. The aim of this systematic review and meta-analysis was to assess the effect of perineural catheters (PNCs) on post-operative pain, post-operative morphine requirement, in-hospital mortality, long term phantom limb pain, and chronic stump pain. METHODS: A systematic review using PubMed, EMBASE via OVID and the Cochrane library from database inception (1946) to 20 October 2020 was performed according to PRISMA guidelines. Studies involving patients undergoing MLLA which reported on post-operative morphine requirement, pain scores, in-hospital mortality, phantom limb pain (PLP), and chronic stump pain were included. Studies comparing PNC use with epidural or wound site local anaesthetic infusions were excluded. Outcome data were extracted from individual studies and meta-analysis was performed using a random effects (Mantel-Haenszel) model for dichotomous data using an odds ratio (OR) summary statistic with 95% confidence intervals (CI), and with an inverse variance random effects model for continuous data using a standardised mean difference (SMD) summary statistic with 95% CIs. Sensitivity analyses were performed for post-operative pain scores and post-operative morphine requirement. Study quality was assessed using the Downs and Black score, and outcomes were assessed using the GRADE tool. RESULTS: Ten studies reporting on 731 patients were included, with 350 patients receiving a PNC and 381 receiving standard care. PNC use is associated with a reduction in post-operative pain (SMD -0.30, 95% CI -0.58 - -0.01, p = .040, I2 = 54%, GRADE quality of evidence: low) and post-operative morphine requirements (SMD -0.63, 95% CI -1.03 - -0.23, p = .002, I2 = 75%, GRADE quality of evidence: moderate), although the effect of PNC on reduced post-operative morphine requirements is lost on sensitivity analysis of randomised trials only (p = .40). No demonstrable effect was found on in-hospital mortality, PLP, or chronic stump pain (GRADE quality of evidence: low). CONCLUSION: PNC use in amputees is associated with a significant reduction in post-operative pain scores and post-operative morphine requirements, although this latter finding is lost on sensitivity analysis of randomised trials only.

A Systematic Review and Narrative Synthesis of Risk Prediction Tools Used to Estimate Mortality, Morbidity, and Other Outcomes Following Major Lower Limb Amputation.

OBJECTIVE: The decision to undertake a major lower limb amputation can be complex. This review evaluates the performance of risk prediction tools in estimating mortality, morbidity, and other outcomes following amputation. METHODS: A systematic review was performed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The MEDLINE, Embase, and Cochrane databases were searched to identify studies reporting on risk prediction tools that predict outcomes following amputation. Outcome measures included the accuracy of the risk tool in predicting a range of post-operative complications, including mortality (both short and long term), peri-operative morbidity, need for re-amputation, and ambulation success. A narrative synthesis was performed in accordance with the Guidance on the Conduct of Narrative Synthesis In Systematic Reviews. RESULTS: The search identified 518 database records. Twelve observational studies, evaluating 13 risk prediction tools in a total cohort of 61 099 amputations, were included. One study performed external validation of an existing risk prediction tool, while all other studies developed novel tools or modified pre-existing generic calculators. Two studies conducted external validation of the novel/modified tools. Nine tools provided risk estimations for mortality, two tools provided predictions for post-operative morbidity, two for likelihood of ambulation, and one for re-amputation to the same or higher level. Most mortality prediction tools demonstrated acceptable discrimination performance with C statistic values ranging from 0.65 to 0.81. Tools estimating the risk of post-operative complications (0.65 - 0.74) and necessity for re-amputation (0.72) also performed acceptably. The Blatchford Allman Russell tool demonstrated outstanding discrimination for predicting functional mobility outcomes post-amputation (0.94). Overall, most studies were at high risk of bias with poor external validity. CONCLUSION: This review identified several risk prediction tools that demonstrate acceptable to outstanding discrimination for objectively predicting an array of important post-operative outcomes. However, the methodological quality of some studies was poor, external validation studies are generally lacking, and there are no tools predicting other important outcomes, especially quality of life.

Editor's Choice - Systematic Review and Meta-Analysis of Wound Adjuncts for the Prevention of Groin Wound Surgical Site Infection in Arterial Surgery.

OBJECTIVE: Groin incision surgical site infections (SSIs) following arterial surgery are common and are a source of considerable morbidity. This review evaluates interventions and adjuncts delivered immediately before, during, or after skin closure, to prevent SSIs in patients undergoing arterial interventions involving a groin incision. DATA SOURCES: MEDLINE, EMBASE, and CENTRAL databases were searched. REVIEW METHODS: This review was undertaken according to established international reporting guidelines and was registered prospectively with the International prospective register of systematic reviews (CRD42020185170). The MEDLINE, EMBASE, and CENTRAL databases were searched using pre-defined search terms without date restriction. Randomised controlled trials (RCTs) and observational studies recruiting patients with non-infected groin incisions for arterial exposure were included; SSI rates and other outcomes were captured. Interventions reported in two or more studies were subjected to meta-analysis. RESULTS: The search identified 1 532 articles. Seventeen RCTs and seven observational studies, reporting on 3 747 patients undergoing 4 130 groin incisions were included. A total of seven interventions and nine outcomes were reported upon. Prophylactic closed incision negative pressure wound therapy (ciNPWT) reduced groin SSIs compared with standard dressings (odds ratio [OR] 0.34, 95% CI 0.23 - 0.51; p < .001, GRADE strength of evidence: moderate). Local antibiotics did not reduce groin SSIs (OR 0.60 95% CI 0.30 - 1.21 p = .15, GRADE strength: low). Subcuticular sutures (vs. transdermal sutures or clips) reduced groin SSI rates (OR 0.33, 95% CI 0.17 - 0.65, p = .001, GRADE strength: low). Wound drains, platelet rich plasma, fibrin glue, and silver alginate dressings did not show any significant effect on SSI rates. CONCLUSION: There is evidence that ciNPWT and subcuticular sutures reduce groin SSI in patients undergoing arterial vascular interventions involving a groin incision. Local antibiotics did not reduce groin wound SSI, although the strength of this evidence is lower. No other interventions demonstrated a significant effect.

Microcirculatory Flux and Pulsatility in Arterial Leg Ulcers is Increased by Intermittent Neuromuscular Electrostimulation of the Common Peroneal Nerve.

BACKGROUND: Neuromuscular electrical stimulator (NMES) devices increase blood flow to the lower limb by a process of intermittent muscular contraction initiated by a transdermal stimulus to the common peroneal nerve. However, its effects on localized microvascular blood supply to lower limb wounds are unknown. This study is a single-center open label study measuring the effect of neuromuscular stimulation of the common peroneal nerve on the microvascular blood flow within the wound bed of arterial leg ulcers. METHODS: Eights patients with ischemic lower limb wounds had an NMES (geko™) applied to the common peroneal nerve. Baseline and intervention analysis of blood flow to the wound bed and edge was performed using Laser Speckle Contrast Imaging. Mean flow (flux) and pulse amplitude (pulsatility) were measured. RESULTS: Stimulation of the common peroneal nerve with the NMES resulted in a significantly increased flux and pulsatility in both the wound bed and the wound edge in all 8 patients. CONCLUSIONS: Neuromuscular electrical stimulation immediately increases microcirculatory blood flow to the wound bed and edge in patients with ischemic lower limb wounds. These data may provide mechanistic insight into the clinical efficacy of NMES in healing wounds. www.clinicaltrials.gov NCT03186560.

Early and Long Term Outcomes Following Long Posterior Flap vs. Skew Flap for Below Knee Amputations.

OBJECTIVE: To compare outcomes between long posterior flap (LPF) and skew flap (SF) amputation over a 13 year period. METHODS: This was a retrospective observational cohort study. Consecutive patients undergoing a LPF or SF below knee amputation (BKA) over a 13 year period at one hospital were identified. Both techniques were performed regularly, depending on tissue loss and surgeon preference. The primary outcome was surgical revision of any kind. Secondary outcomes included revision to above knee amputation (AKA), length of hospital stay (LOS), and mortality. A smaller cohort of patients who were alive and unilateral below knee amputees were contacted to ascertain prosthetic use and functional status. RESULTS: In total, 242 BKAs were performed in 212 patients (125 LPF and 117 SF; median follow up 25.8 months). Outcomes for the two groups were equivalent for surgical revision of any kind (27 LPF vs. 31 SF; p = .37), revision to an AKA (18 LPF vs. 14 SF; p = .58), LOS (29 days for LPF vs. 28 days for SF; p = .83), and median survival (23.9 months for LPF vs. 28.8 months for SF; p = .89). Multivariable analysis found amputation type had no effect on any outcome. Functional scores from a smaller cohort of 40 unilateral amputees who were contactable demonstrated improved outcomes with the LPF vs. the SF (p = .038). CONCLUSION: Both techniques appear equivalent for rates of surgical residual limb failure. Functional outcomes may be better with the LPF.

Development of Core Outcome Sets for People Undergoing Major Lower Limb Amputation for Complications of Peripheral Vascular Disease.

OBJECTIVE: Every year, thousands of patients with peripheral vascular disease undergo major lower limb amputation. Despite this, evidence for optimal management is weak. Core outcome sets capture consensus on the most important outcomes for a patient group to improve the consistency and quality of research. The aim was to define short and medium term core outcome sets for studies involving patients undergoing major lower limb amputation. METHODS: A systematic review of the literature and focus groups involving patients, carers, and healthcare professionals were used to derive a list of potential outcomes. Findings informed a three round online Delphi consensus process, where outcomes were rated for both short and medium term studies. The results of the Delphi process were discussed at a face to face consensus meeting, and recommendations were made for each core outcome set. RESULTS: A systematic review revealed 45 themes to carry forward to the consensus survey. These were supplemented by a further five from focus groups. The consensus survey received responses from 123 participants in round one, and 91 individuals completed all three rounds. In the final round, nine outcomes were rated as "core" for short term studies and a further nine for medium term studies. Wound infection and healing were rated as "core" for both short and medium term studies. Outcomes related to mortality, quality of life, communication, and additional healthcare needs were also rated as "core" for short term studies. In medium term studies, outcomes related to quality of life, mobility, and social integration/independence were rated as "core". The face to face stakeholder meeting ratified inclusion of all outcomes from the Delphi and suggested that deterioration of the other leg and psychological morbidity should also be reported for both short and medium term studies. CONCLUSION: Consensus was established on 11 core outcomes for short and medium term studies. It is recommended that all future studies involving patients undergoing major lower limb amputation should report these outcomes.

Editor's Choice - Direct vs. Indirect Angiosomal Revascularisation of Infrapopliteal Arteries, an Updated Systematic Review and Meta-analysis.

BACKGROUND: The importance of the angiosome concept in tibial artery revascularisation remains controversial. The aim of this review was to assess the outcomes of direct revascularisation (revascularisation to the angiosome of tissue loss; DR) versus indirect revascularisation (IR) in infrapopliteal arteries. METHODS: A previously conducted systematic review was updated according to PRISMA guidelines. Studies comparing DR with IR by both endovascular and surgical means for patients with localised tissue loss were included. Meta-analyses were performed to assess the effect of DR versus IR on wound healing (total and time to healing), limb salvage, mortality, and re-intervention rates, with multiple sensitivity analyses. Outcome data quality was determined using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) tool. RESULTS: Seven studies (2278 limbs) were identified in the updated search, which when combined with the previous search resulted in 22 studies, comprising 4146 limbs, being included. Wound healing rates (odds ratio [OR] 0.51; 95% CI 0.39-0.68, p < 0.001), time to wound healing (standard mean difference [SMD] -1.70; 95% CI -3.34 to -0.07, p = .04) and limb salvage (OR 0.37; 95% CI 0.24-0.58, p < .0001) were significantly better with DR compared with IR. Sensitivity analyses were concordant with the primary analysis for these outcomes, with the exception of the effect of wound healing rates between DR and IR, which was lost on sensitivity analysis for bypass surgery. Mode of revascularisation had no effect on mortality or on re-intervention rates. GRADE outcomes were very low. CONCLUSION: DR of the tibial vessels appears to result in improved wound healing and limb salvage rates compared with IR, with no effect on mortality or re-intervention rates. For surgical revascularisation the importance of DR appears to be lost for wound healing. When possible, these low quality data suggests DR should be undertaken in preference to IR.

The Safety of Device Registries for Endovascular Abdominal Aortic Aneurysm Repair: Systematic Review and Meta-regression.

OBJECTIVES: New and re-designed stent grafts for endovascular aortic aneurysm repair (EVAR) are released regularly. Manufacturers use data from registries to assess stent graft performance, but little is known about the ability of such registries to detect rates of clinically relevant complications. The aim of this paper was to perform a systematic review and meta-analysis to determine pooled failure rates for EVAR stent grafts, to define an acceptable non-inferiority limit for these devices, and then to calculate the number of patients needed for a new device to achieve non-inferiority against published devices. DATA SOURCES AND REVIEW METHODS: MEDLINE and EMBASE were searched for studies reporting outcomes of specific EVAR grafts being used for intact infrarenal abdominal aortic aneurysms, from inception to November 2016. Meta-regression was performed to pool data and calculate the patient numbers needed to detect non-inferiority of a future graft performance. An expert consensus was performed to define adequate standards for device safety. RESULTS: One hundred and forty-seven moderate quality papers involving 27,058 patients were included. Multiple outcomes were pooled. Of these, the estimated rate (±standard error) of overall endoleak (excluding Type II) at 2 years was 5.7 ± 0.6%. The pooled re-intervention rate was 11.1 ± 0.7% at 2 years. There were differences in pooled endoleak rates between different stent graft types. Expert consensus defined non-inferiority as better performance than the worst performing 25% of stent grafts. The most popular outcome in the expert consensus was cumulative endoleak rate (excluding Type II). The number of patients who would need to be enrolled in a registry to demonstrate non-inferiority at this level was 525. Only two of 147 included studies achieved this. The second most popular choice in the expert consensus was re-intervention rate; 492 patients are required to demonstrate this. CONCLUSIONS: Five hundred and twenty-five patients need to be entered into a registry to demonstrate non-inferiority to previous stent grafts. Almost all previous publications have captured lower patient numbers. With performance varying between devices, and new devices being introduced regularly, there is an urgent need to capture higher quality long-term data on EVAR stent grafts.