Major Limb Amputation Research Articles

Indications for and outcomes of major lower limb amputations at a tertiary-referral centre in Australia.

Major amputations are classically associated with significant morbidity and mortality. With the increasing prevalence of risk factors for amputation, namely, diabetes and peripheral arterial disease, we sought to identify the major indications for lower limb amputation in an Australian cohort. A secondary aim was to assess the outcomes, namely, mortality, of amputees over the previous decade. This study assessed all patients undergoing major lower limb amputations between 2012 and 2020. Variables analysed included comorbidities, indication for amputation, in-hospital complications and mortality, duration of hospital stay, and out-patient mortality. 317 amputations were performed on 269 patients. 55% of amputations were below knee, 45% above knee, with one through-knee amputation. Indications included ischaemia (55.2%), infection (30.6%), malignancy (6.9%), trauma (4.4%), and chronic pain or instability (2.5%). In-patient mortality rate was 7.6%, with mortality rates of 21.5% at one year, and 70.1% at 10years. Post-operative complications occurred in 43% of amputations. Rural, regional, and remote (RRR) patients did not suffer disproportionately from major amputations, however, were more likely to require amputations for ischaemia. Patients undergoing amputation for infective causes demonstrated lower mid-term mortality rates compared to those undergoing amputations for ischaemia (56.1 vs 60.4% at 5years, p = 0.007). Major amputations continue to be associated with significant morbidity and mortality, both in the short and long term. Patients undergoing amputations for ischaemic causes demonstrate poorer outcomes than their infective counterparts, with outcomes being even worse in RRR populations. Prevention of amputations via intense management of comorbidities would benefit both patients and the healthcare system.

Sex-Related Outcomes Following Drug Balloon Angioplasty in Patients from the BIOLUX P-III Registry: A Subgroup Analysis

PurposeTo evaluate the use of drug-coated balloons in a real-world patient population with peripheral arterial disease and analyse the impact of sex on mid-term outcomes following their utilisation.MethodsThe BIOLUX P-III is a prospective, international, multi-centre, registry of patients with infra-inguinal lesions treated using the Passeo-18 Lux, a drug-coated balloon. Our study is a 24-month subgroup analysis of these patients; primary endpoints were freedom from major adverse events and clinically driven target lesion re-vascularisation within 12 months post-intervention.ResultsOf the 877 patients in the registry, 561 (64.0%) were male and 316 (36.0%) were female. Chronic limb threatening ischaemia (Rutherford class ≥ 4) occurred in 35.7% of males and 40.6% of females. Rates of freedom from major adverse events and clinically driven target lesion re-vascularisation at 12 months were 87.3% (95% confidence interval [CI] 84.2–89.9) and 90.4% (95% CI 86.5–93.3), and 92.3% (95% CI 89.9–94.1) and 92.9% (95% CI 89.7–95.1) in males and females, respectively. All-cause mortality at 24 months was 12.0% (95% CI 9.4–15.3) in males and 11.9% (95% CI 8.6–16.5) in females. The major target limb amputation rate at 24 months was 9.1% (95% CI 6.9–11.9) in males and 4.0% (95% CI 2.3–7.0) in females.ConclusionTreatment with the Passeo-18 Lux DCB demonstrated high efficacy and low complication rates. Despite the greater proportion of chronic limb threatening ischaemia observed in females, males were at a greater risk of ipsilateral major limb amputation and major adverse events following drug-coated balloon utilisation.Clinical Trial RegistrationNCT02276313.Level of EvidenceLevel 4.

The Clinical Utility of D-Dimer and Prothrombin Fragment (F1+2) for Peripheral Artery Disease: A Prospective Study.

D-dimer and prothrombin fragment (F1+2) levels are elevated in patients with peripheral artery disease (PAD). We examined their prognostic potential in predicting decreasing ABI and major adverse limb events (MALE). A total of 206 patients were recruited from St. Michael’s Hospital and followed for two years. Baseline plasma concentrations of D-dimer and F1+2 were recorded. Pearson’s correlation was used to assess the correlation between the biomarkers and ABI at year 2. During follow-up, multivariable Cox proportional hazard analysis was performed to investigate their role in predicting decreasing ABI (defined as change in ABI > −0.15) and MALE (defined as the need for arterial intervention or major limb amputation). Cumulative survival was assessed using Kaplan–Meier analysis. Baseline D-dimer and F1+2 levels were elevated in PAD patients (median (IQR) 1.34 (0.80–2.20) for D-dimer and 3.60 (2.30–4.74) for F1+2; p = 0.001) compared to non-PAD controls (median (IQR) 0.69 (0.29–1.20) for D-dimer and 1.84 (1.17–3.09) for F1+2; p = 0.001). Both markers were negatively correlated with ABI at year 2 (r = −0.231 for D-dimer, r = −0.49 for F1+2; p = 0.001). Cox analysis demonstrated F1+2 and D-dimer to be independent predictors of PAD status (HR = 1.27, 95% CI = 1.15–1.54; p = 0.013 for D-dimer and HR = 1.28, 95% CI = 1.14–1.58; p = 0.019 for F1+2). Elevated baseline concentrations of D-dimer and F1+2 were associated with high incidence of decreasing ABI and 1- and 2-year event-free survival (62% and 86%, respectively). Combined analysis of D-dimer and F1+2 provides important prognostic information that facilitates risk stratification for future disease progression and MALE outcomes in patients with PAD.

P137. HIGH-RISK OPIOID PRESCRIBING AND PERSISTENT OPIOID USE AFTER MAJOR LOWER LIMB AMPUTATION AMONG MEDICARE BENEFICIARIES

PURPOSE: Recently, quality improvement efforts have focused on mitigating opioid related harms among postamputation patients. However, the prevalence of high-risk opioid prescribing practices is not well described, nor the risk factors associated with persistent opioid use among major lower limb amputation patients. METHODS: We reviewed 2009-2018 Medicare claims of major lower limb amputation patients. Prolonged opioid use was defined as one opioid prescription filled within 90-days after discharge and another within 90-180 days. High-risk opioid prescribing included overlapping opioid prescriptions, overlapping benzodiazepine-opioid prescriptions, high daily-doses>100 OMEs, multiple prescribers, and new long-acting opioid use within 90-days postoperatively. We used the Cochran-Armitage-Trend-Test to determine trends in high-risk prescribing over time, and multilevel mixed-effects logistic regression to determine predictors of prolonged use. RESULTS: In total, 5,191 patients were included (Chronic opioid-users=1,432; Intermittent opioid-users=2,195; Opioid-Naïve=1,564). Rates of high-risk prescribing did not change significantly during the study period, and 82.3% chronic (p=0.65), 37.2% non-chronic (p=0.08), and 15.5% opioid-naïve (p=0.74) users were exposed to high-risk prescribing. Individuals with prior opioid fills were more likely to have prolonged use (chronic users OR=2.21, p=0.033; non-chronic users OR=4.46, p<0.001). Among non-chronic users, age<55 years (OR=1.41, p=0.04), concurrent gabapentinoid fills (OR=1.92, p<0.001), and sedative/anxiolytic fills (OR=1.75, p<0.001) were associated with prolonged use. CONCLUSION: Among major lower extremity amputation patients high-risk prescribing practices are common, and have not changed over time. Interventions that focus on tailoring postoperative pain management to preoperative risk factors, including preoperative opioid exposure, will be of high-value to optimize postamputation pain and encourage safe opioid stewardship.

Paclitaxel-coated balloons versus percutaneous transluminal angioplasty for infrapopliteal chronic total occlusions: the IN.PACT BTK randomised trial.

Data are mixed concerning the safety and effectiveness of drug-coated balloons (DCBs) for treating below-the-knee (BTK) lesions. The aim of this study was to assess the safety and effectiveness of the IN.PACT 014 paclitaxel-coated balloon catheter versus conventional percutaneous transluminal angioplasty (PTA) for infrapopliteal chronic total occlusions (CTOs) in patients with chronic limb-threatening ischaemia (CLTI). The IN.PACT BTK randomised study is a prospective, multicentre, randomised pilot study. Fifty CLTI participants (Rutherford clinical category 4-5) with BTK CTOs were randomised 1:1 to DCB (N=23) or PTA (N=27). The primary effectiveness endpoint was late lumen loss (LLL) at 9 months post procedure. Safety outcomes up to 9 months included all-cause mortality, major target limb amputation, and clinically driven target lesion revascularisation (CD-TLR). Mean lesion length was 215.41±83.81 mm in the DCB group and 218.19±80.43 mm for PTA (p=0.806). The 9-month angiographic LLL was 0.892±0.774 mm for the DCB group and 1.312±0.720 mm for the PTA group (p=0.070) in a classic analysis, and 0.592±0.944 mm for DCB and 1.260±0.810 mm for PTA (p=0.017) in a subsegmental analysis. The Kaplan-Meier estimated freedom from CD-TLR up to 9 months was 91.1% for DCB and 91.8% for PTA (log-rank p=0.942). At 9 months, 1 patient died in the DCB group and 2 in the PTA group (p=1.000); there were no major target limb amputations in either arm. The 9-month subsegmental LLL was lower after treatment with the IN.PACT 014 DCB compared with PTA with no differences in safety or revascularisation events in a small complex population of patients with BTK CTOs. gov: NCT02963649.

Distal Bypass Versus Infrageniculate Endovascular Intervention for Chronic Limb-Threatening Ischemia.

Chronic limb-threatening ischemia (CLTI) carries a high risk of amputation and warrants urgent intervention. CLTI involving the infrageniculate vessels, in particular, carries a considerably higher risk of major limb amputation. Open surgical bypass is the historical gold standard for the treatment of tibial arterial disease; however, endovascular therapy provides an attractive alternative in this high-risk patient population. In this article, we review the existing literature regarding distal bypass and infrageniculate endovascular intervention in patients with CLTI.

Development of a coordinated acute diabetic foot pathway for management of acute diabetic foot infection and ulceration.

Diabetic foot ulceration (DFU) has become an increasingly common emergency presentation. These patients are presenting at a younger age and with increasingly complex co-morbidities. They require frequent hospitalisation for management of DFU which has significant consequences for management of health resources but also for quality of life in the diabetic patient population. The aim of this study was to evaluate the impact of the development of a coordinated, streamlined acute diabetic foot pathway for management of in-patients presenting as emergencies with DFU on length of stay, re-admission to hospital and minor and major amputations. A dedicated acute diabetic foot pathway was introduced to St. Vincent's University Hospital (SVUH) in April 2016. Management of patients admitted urgently to the emergency department or out-patient clinics of St. Vincent's University Hospital during the 3-year period before April 2016 was compared to that of patients admitted in the 3years after April 2016 following introduction of the acute diabetic foot pathway. Demographic data hospital length of stay, need for re-admission, major and minor amputations performed and cost of hospital stay were compared before and after introduction of the pathway. There were 931 admissions with acute diabetic foot ulceration or infection between January 2012 and December 2019; 419 were admitted between January 2012 and March 2016 and 512 between April 2016 and December 2019. There was no difference in demographic data between the two time periods. Length of stay decreased from 13 +/- 4.24 to 3 +/- 1.41days between the two time periods (p < 0.001). Re-admission rates within 30days decreased from 21.7 to 10.1% (p < 0.05). The number of major lower limb amputations decreased over the two time periods from 8.8 to 7.2% with a concomitant increase in minor amputations from 16.7 to 25.3%. Risk of major lower limb amputation was significantly higher in those patients living more than 20km from the hospital. Costs associated with in-patient stay for management of DFU decreased from €9,247,700 to €8,988,100 despite an 18% increase in the number of patients treated and a 9.9% increase in hospital admissions. Introduction of a dedicated, streamlined pathway involving multi-disciplinary input resulted in a significant improvement in patient management as assessed by length of hospital stay and need for re-admission. While the number of major lower limb amputations has decreased there has been a significant increase in the number of minor amputations.

Editor's Choice – Covered vs. Bare Metal Stents in the Reconstruction of the Aortic Bifurcation: Early and Midterm Outcomes from the COBRA European Multicentre Registry

To report outcomes following endovascular revascularisation for severe aorto-iliac occlusive disease (AIOD) using covered (CS) or bare metal (BMS) stent(s). This was a retrospective cohort study including patients who underwent treatment with CS or BMS for AIOD between November 2012 and March 2020 in 12 European centres. Outcome measures included death, freedom from target lesion revascularisation (TLR), major amputation, and major adverse cardiac and cerebrovascular events (MACCE). Overall, 252 patients (53% males; mean age 65 ± 10 years) were included (102 with a bare metal and 150 with a covered aortic stent); 122 (48%) presented with chronic limb threatening ischaemia (CLTI). Severe arterial calcification was noted in > 65% of patients, 70% presented with Trans-Atlantic Societies Consensus (TASC) D lesions, 32% and 46% had aortic or iliac chronic total occlusion (CTO), respectively. Median follow up was 17 months (range 6 - 40; none lost to follow up). Median inpatient stay was two days (range two to four). During the first 30 days, two patients died (both with covered aortic stents, because of cardiovascular events), none required TLR, two (1%) patients had a major amputation (all presented with CLTI), and three (1%) had a MACCE. At 17 months, mortality (BMS 14% vs. CS 7%, hazard ratio [HR] 0.97, 95% confidence interval [CI] 0.42 - 2.26, p= .94, log rank test) and TLR (11% vs. 10%, HR 1.98, 95% CI 0.89 - 4.43, p= .095) did not differ statistically significantly between the two groups; only three patients had a major limb amputation during late follow up (all with a covered stent). In a multivariable model, the use of an aortic CS did not influence TLR. In a conditional Cox regression, however, the concomitant use of aortic and iliac CSs was associated with improved freedom from TLR. Endovascular reconstruction with aortic CSs or BMSs for severe AIOD showed comparable midterm performance. The use of both aortic and iliac CSs seems to be associated with reduced TLR.

Analysis of a Machine Learning–Based Risk Stratification Scheme for Chronic Limb-Threatening Ischemia

Valid risk stratification schemes are key to performing comparative effectiveness research; however, for chronic limb-threatening ischemia (CLTI), risk stratification schemes have limited efficacy. Improved, accurate, comprehensive, and reproducible risk stratification models for CLTI are needed. To evaluate the use of topic model cluster analysis to generate an accurate risk prediction model for CLTI. This multicenter, nested cohort study of existing Project of Ex Vivo Vein Graft Engineering via Transfection (PREVENT) III clinical trial data assessed data from patients undergoing infrainguinal vein bypass for the treatment of ischemic rest pain or ischemic tissue loss. Original data were collected from January 1, 2001, to December 31, 2003, and were analyzed in September 2021. All patients had 1 year of follow-up. Supervised topic model cluster analysis was applied to nested cohort data from the PREVENT III randomized clinical trial. Given a fixed number of clusters, the data were used to examine the probability that a patient belonged to each of the clusters and the distribution of the features within each cluster. The primary outcome was 1-year CLTI-free survival, a composite of survival with remission of ischemic rest pain, wound healing, and freedom from major lower-extremity amputation without recurrent CLTI. Of the original 1404 patients, 166 were excluded because of a lack of sufficient feature and/or outcome data, leaving 1238 patients for analysis (mean [SD] age, 68.4 [11.2] years; 800 [64.6%] male; 894 [72.2%] White). The Society for Vascular Surgery Wound, Ischemia, and Foot Infection grade 2 wounds were present in 543 patients (43.8%), with rest pain present in 645 (52.1%). Three distinct clusters were identified within the cohort (130 patients in stage 1, 578 in stage 2, and 530 in stage 3), with 1-year CLTI-free survival rates of 82.3% (107 of 130 patients) for stage 1, 61.1% (353 of 578 patients) for stage 2, and 53.4% (283 of 530 patients) for stage 3. Stratified by stage, 1-year mortality was 10.0% (13 of 130 observed deaths in stage 1) for stage 1, 13.5% (78 of 578 patients) for stage 2, and 20.2% (105 of 521 patients) for stage 3. Similarly, stratifying by stage revealed major limb amputation rates of 4.2% (5 of 119 observed major limb amputations in stage 1) for stage 1, 10.8% (55 of 509 patients) for stage 2, and 18.4% (81 of 440 patients) for stage 3. Among survivors without a major amputation, the rates of CLTI recurrence were 9.2% (11 of 119 observed recurrences in stage 1) for stage 1, 24.9% (130 of 523 patients) for stage 2, and 29.6% (132 of 446 patients) for stage 3. The topic model cluster analysis in this cohort study identified 3 distinct stages within CLTI. Findings suggest that CLTI-free survival is an end point that can be accurately and reproducibly quantified and may be used as a patient-centric outcome.

Current Trends in the Management of Lower Limb Amputations

Background: Lower limb amputation is a major but preventable public health problem in a developing nation such as India. It is a burden for the patients as well as their families not only economically but also socially and psychologically. The duration of treatment lasts from a few days to several months and depends on the extent of disease, level of amputation and patient’s comorbid status. The purpose of this study is to outline the demographics, various indications and the complications of lower limb amputations, the newer interventions in the management of lower limb amputations and to evaluate our experience in managing such patients presenting at a tertiary care hospital in South India. Methodology: This is a prospective study done between the period of December 2019 and December 2020 at Sapthagiri Medical College and Research Centre, Bengaluru, Karnataka, India. All patients undergoing lower limb amputation during this time period were included in the study. Results: A total of 50 patients were included into the study. Majority of the patients were males (72%). The most common indication for major limb amputation is peripheral arterial occlusive disease (PAOD) 50% and Diabetic foot in 36.96%. Below knee amputation was the most common procedure performed in 52.17%. The most common additional procedures performed were wound debridement in 23.91%, secondary suturing in 19.57%. Revision amputation rate was 8.7%. Post-operative complication rate was 39.13% and surgical site infection was the most common complication accounting for 17.39%. 8% of the patients underwent vascular interventions which prevented major limb loss. Conclusion: Diabetic foot and PAOD of lower limbs that progressed to gangrene are the most common indications for lower limb amputations, majority of which can be prevented by health education and early presentation. Appropriate management by applying newer trends such as vascular intervention can help in reducing morbidity.

Spatial analysis of factors impacting lower limb major amputation rates in Hungary: Is geography partially destiny?

Background: Lower limb major amputations represent a substantial public health burden in Hungary, where previous research revealed markedly high rates with significant spatial variations. Therefore, we aimed to assess to what extent healthcare and socio-economic factors in the local environment explain the regional disparity. Patients and methods: In a retrospective cohort analysis, based on the healthcare administrative data of the Hungarian population, lower limb major amputations were identified from 1st of January 2017 to 31st of December 2019. The permanent residence of the amputees on the local administrative level (197 geographic units) was used to identify potential healthcare (outpatient care, revascularisation activity) and socio-economic (educational attainment, local infrastructure and services, income and employment) determinants of amputations. Spatial effects were modelled using the spatial Durbin error regression model. Results: 10,209 patients underwent 11,649 lower limb major amputations in the observational period. In our spatial analysis, outpatient care was not associated with local amputation rates. However, revascularisation activity in a geographic unit entailed an increased rate of amputations, while revascularisations in the neighbouring areas were associated with a lower rate of amputations, resulting in an overall neutral effect (β=-0.002, 95% CI: -0.05 - 0.04, p=0.96). The local socio-economic environment had a significant direct inverse association with amputations (β=-7.45, 95% CI: -10.50 - -4.42, p<0.0001) . Our spatial model showed better performance than the traditional statistical modelling (ordinary least squares regression), explaining 37% of the variation in amputations rates. Conclusions: Regional environmental factors explain a substantial portion of spatial disparities in amputation practice. While the socio-economic environment shows a significant inverse relationship with the regional amputation rates, the impact of the local healthcare-related factors (outpatient care, revascularisation activity) is not straightforward. Unravelling the impact of the location on amputation practice requires complex spatial modelling, which may guide efficient healthcare policy decisions.

Outcomes in Lower Limb Amputation Rehabilitation

Abstract Introduction: Lower leg amputations affect mobility and can be solved with prosthesis. Despite being included in the Package of Rehabilitation Interventions created by the World Health Organisation, there are lacks in rehabilitation outcome research. Objectives: Reveal the rehabilitation outcomes and, secondarily, determine predictors of prosthesis use for at least two years. Methods: Retrospective cohort study of patients with major lower limb amputations aged between 18 and 70 years with no other disabilities. Rehabilitation outcomes and the predictors of prosthesis use at discharge (time II) compared to the two-year follow-up (time III) were evaluated. Results: 703 patients were included. At time II, 95.73% (673) completed the treatment, with a prosthetic gait rate of 73.12%. Age was a predictor for prosthetic gait, as each one-year increase in age corresponded to a 3.29% decrease in prosthesis use. At time III, 54.21% of the patients had higher prosthetic gait performance, for 2 years at least, requiring a new device. Conclusion: The rehabilitation ensures mobility though high-performance prosthetic gait regardless of age, sex, or aetiology, for at least 2 years from rehabilitation discharge. Though with a lower prosthesis use rate with increasing age.

Association of Peripheral Serum MicroRNAs With Persistent Phantom Limb Pain in Individuals With Amputation.

Individuals with major limb amputation(s) frequently experience phantom limb sensations, which are described as vivid impressions of either parts or entire missing limb(s). Despite the high incidence and prevalence of phantom limb pain, the underlying pathophysiology of phantom limb pain remains poorly understood. The objective of this study was to evaluate a possible role of microRNAs in the pathophysiology of phantom limb pain. Adults with acquired limb amputation and varying degrees of phantom limb pain consented to provide clinical data and blood samples. One hundred forty participants with single or multiple limb amputation(s) were enrolled. The Visual analog scale and neuropathic pain symptom inventory were administered to evaluate the pain. Serum samples were analyzed for microRNA expression and bioinformatic analysis was performed. Sixty-seven participants did not experience phantom limb pain, whereas 73 participants experienced varying severities of phantom limb pain measured on a pain scale. Linear regression analysis suggested that the time since amputation is inversely related to severity of the pain. A significantly increased expression of 16 microRNAs was observed in participants experiencing phantom limb pain. Bioinformatic analysis shows a possible role of these microRNAs in regulating genes expressed in peripheral neuropathy. This study provides the first evidence of association of microRNA in phantom limb pain.

Patient and Geographical Disparities in Functional Outcomes After Major Lower Limb Amputation in Australia

Major lower limb amputations are associated with considerable disability, low quality of life, and poor rates of returning to work, all of which are often attributed to the poor level of functional mobility that amputees experience postoperatively. This study aimed to quantify ambulatory outcomes after major lower limb amputation and identify potential prognostic factors for patients most likely to achieve ambulation and prosthesis use, with the hypothesis that variation in outcomes correlates to age, level of amputation, and place of residence at the time of amputation. This retrospective cohort study identified functional outcomes for patients who had lower limb amputations between 2012 and 2020. Patients were identified from the 10th revision of the International Classification of Diseases Australian Modification (ICD-10-AM)-coded state-wide government-maintained hospital administrative data by procedure codes for lower limb amputation. The primary outcomes were ambulation at the time of discharge from acute hospital stay, discharge destination, and prosthesis use. Variables for adjustment included patient age, comorbidity, level of amputation, and place of residence. Three-hundred and seventeen amputations were performed in 269 patients. Most procedures were transtibial amputations (56.4%) and for ischemic/infective indications (84%). Thirty-seven percent of patients were ambulating independently at the time of discharge and 55.9% demonstrated independent mobility with prosthesis at follow-up. Ambulation at the time of discharge predicted patients who were more likely to return home rather than residential or hospital care (odds ratio [OR] 1.8 95%; confidence interval [CI] 1.0-3.2). Patients with transtibial amputation were more likely to achieve prosthesis use than transfemoral (OR 4.4, 95% CI 2.1-9.5), after adjusting for age, comorbidity, and geographical factors. Mobility and prosthesis use was lowest in patients who were older, had transfemoral amputations, and resided in regional or rural areas. The significant outcome disparities identified in this cohort study highlight the need for targeted quality interventions aimed at improving functional outcomes for patients undergoing major amputation for peripheral artery disease.

The adverse impact of pre-operative anaemia on survival following major lower limb amputation.

Approximately 5000 major lower-limb amputations (MLLA) for PAD occur per-annum in the UK with clinical outcomes being poor for this high-risk cohort of patients. Existing evidence suggests that anaemic surgical patients have an increased 30-day mortality, but this has not been explored in the context of MLLA. Recent prioritization processes suggested that MLLAs are a target area for research into outcome improvement. This cohort study evaluates the impact of anaemia on the outcome of MLLA to understand if optimization might improve outcomes. All PAD patients undergoing MLLA during 2015-2018 at a tertiary vascular centre were reviewed. Patients were stratified into groups; non-anaemia (>12g/dL), mild-anaemia (12-10g/dL) and severe-anaemia (<10g/dL) by pre-operative haemoglobin (Hb). Primary outcome was overall survival by Kaplan-Meier. Secondary outcomes included length of stay (LOS), post-operative blood-transfusion, surgical-site infection (SSI) and myocardial infarction (MI). Cox-proportional-hazard and receiver-operator characteristics (ROC) analyses were conducted. 345 patients were followed up over (mean) 23months. 105 were non-anaemic, 111 mildly anaemic and 129 severely anaemic. Patients with severe-anaemia had a higher incidence of heart and renal failure (p = 0.003) than those with non- or mild-anaemia. Overall survival worsened significantly with increasing anaemia (p = 0.001). LOS was significantly longer in mild-anaemia which is 26 (16-43) days, (p = 0.006) and severe-anaemia of 28 days (17-40), (p < 0.001) compared to non-anaemia of 18 (10-30) days. Post-operative blood-transfusion (RBC) was required more frequently in 70.5% of severely anaemic patients (p < 0.001), compared to mildly anaemic (24.3%) and non-anaemic (7.6%) patients, with those receiving RBCs having a significantly worse survival. There was no difference in MI, SSI or wound dehiscence. Anaemia was significantly associated with mortality; (HR 1.7 (1.04-2.78), p = 0.03). A minimum-Hb of 10.4g/L (by ROC) was identified as a cutoff Hb for an increased risk of mortality. Pre-operative anaemia is associated with worse outcome following MLLA, with increasing severity of anaemia associated with increasing mortality and RBC transfusion being potentially detrimental. More work is required to prospectively evaluate this relationship in this complex and multi-morbid cohort of patients.

Prehabilitation-plus for patients undergoing major lower limb amputation may reduce acute hospital and total hospital length of stay: a retrospective, matched, case-controlled pilot service evaluation

Background/Aims ‘Prehabilitation’ refers to interventions that seek to enhance a person's functional capacity to help withstand a forthcoming stressor, such as major surgery. There is little research evaluating prehabilitation before major lower limb amputation. This study evaluated if a comprehensive multidisciplinary pre-admission programme, which included prehabilitation plus other interventions (eg education, home assessment and modifications), hereinafter called ‘prehabilitation-plus’, might shorten hospital length of stay by allowing earlier discharge home from hospital after major lower limb amputation. The aim of this study was to investigate the effect of prehabilitation-plus on hospital length of stay and discharge destination for patients undergoing major lower limb amputation. Methods Seven patients receiving prehabilitation-plus were retrospectively matched with seven control patients in this case-controlled pilot service evaluation. Prehabilitation-plus was provided by a multidisciplinary team. Hospital length of stay was compared using Mann–Whitney U tests and discharge destination using Fisher's exact test. Results Acute hospital and total hospital length of stay were significantly lower in the prehabilitation-plus group than the control group (P=0.038 and 0.011 respectively). No significant difference was seen for rehabilitation hospital length of stay (P=0.400). More prehabilitation-plus patients were discharged directly home after their acute hospital stay, but this was not significant (P=0.286). Conclusions Patients who received prehabilitation-plus had reduced acute hospital and total hospital length of stay compared to matched control patients. While these preliminary results are promising for the ability of programmes such as prehabilitation-plus to reduce hospital length of stay, further studies with more robust designs are required to confirm and extend this finding.

Clinical and Economic Impact of COVID-19 in Vascular Surgery at a Tertiary University “Hub” Hospital of Italy

BackgroundSince the first cases of a novel respiratory disease were reported in December 2019, coronavirus disease (COVID-19) Emergency State (Cov-ES) caused a worldwide outbreak requiring a complete reorganization of the healthcare system and new management of its personnel; aim of this study was to analyze the clinical and financial impact of Cov-ES in the Department of Vascular Surgery at a Tertiary University “Hub” Hospital in northeast Italy.MethodsDifferences in clinical practice according to Diagnostic Related Group (DRG) and International Statistical Classification of Diseases (ICD) and Related Health Problems and the financial impact of Cov-ES were considered. Vascular procedures performed between March 2019 and December 2019 (Prepandemic) were compared to those performed in the period March–December 2020 (Pandemic). Prepandemic and pandemic reimbursements of all vascular activities and the top 3 vascular diagnoses were evaluated.ResultsPrepandemic versus pandemic era documented a decrease of vascular consultations performed (2,882 vs. 2,270, −21.2%). The number of total vascular procedures decreased from 997 to 797 (−20.1%) with a higher reduction observed in outpatient surgical activities (247 to 136, −45.0%, P = 0.0005) rather than inpatient surgical activities (750 vs. 661, 11.9%, P = 0.02). Length of hospital stay (LOS) increased from 3.3 ± 2.7 days in prepandemic to 5.3 ± 3.9 in the pandemic era (P = 0.004). Among patients with limb-threatening ischemia, the rate of major limb amputation was higher in the pandemic (3.3% vs. 5.4%, respectively, P = 0.02), and a higher rate of elective hospitalization procedures was performed as urgent/emerging setting after clinical deterioration (2.8 % vs. 6.4%, P = 0.0002). According to DRG classification, an increase of “complicated” limb-threatening ischemia (DRG 554) and aortic aneurysm (DRG 110) was observed prepandemic to pandemic (+84.2% and +25.0%, respectively). Total reimbursement for vascular activities between pandemic versus prepandemic was 4,646,108€ vs. 5,054,398€, respectively (−8.0%). Management of “complicated” limb-threatening ischemia (DRG 554) and aortic aneurysm (DRG 110) required a higher clinical and financial support that was translated into higher economic reimbursement during the pandemic (273,035€ vs. 150,005€, +82.0% and 749,250€ vs. 603,680€, +24.1%, respectively).ConclusionsDuring the pandemic, the main resources were employed for the treatment of limb-threatening ischemia, aortic aneurysm, and carotid stenosis. Inpatient activities documented an increase in major limb amputation and LOS. An increased reimbursement for each vascular procedure and for all “complicated” diagnoses revealed that the more serious and resource-demanding pathology occurred in this period.

2-Year Results With a Sirolimus-ElutingSelf-Expanding Stentfor Femoropopliteal Lesions: The First-in-Human ILLUMINA Study.

The aim of the study was to assess 24-month efficacy and safety of a novel drug-eluting stent (DES) for femoropopliteal interventions with an innovative stent design and abluminal reservoir technology releasing the amphilimus formulation (sirolimus plus fatty acid) for efficient drug transfer and optimized release kinetics. DES releasing paclitaxel exhibited good patency rates after femoropopliteal interventions. No benefit has been reported when sirolimus or everolimus were used for antiproliferative stent coating. Within a multicenter, first-in-man, single-arm study, 100 patients with symptomatic femoropopliteal disease (Rutherford category 2-4, mean lesion length 5.8 ± 3.9cm, 35.0% total occlusions) were treated with the NiTiDES stent (Alvimedica). Two-year follow-up included assessment of primary patency (defined as absence of clinically driven target lesion revascularization or binary restenosis with a peak systolic velocity ratio >2.4 by duplex ultrasound), safety, functional, and clinical outcomes. At 24months, Kaplan-Meier estimates of primary patency and freedom from clinically driven target lesion revascularization were 83.4% (95%CI: 73.9%-89.6%) and 93.1% (95%CI: 85.3%-96.9%), respectively. Over the study period, 3 deaths were reported with no major limb amputation. Functional and clinical benefits were sustained, as 82.1% of patients fell into Rutherford category 0 or 1 at 24months, which was associated with preserved improvements in all walking disability questionnaire scores. The 2-year results of the ILLUMINA (Innovative siroLimus seLf expanding drUg-eluting stent for the treatMent of perIpheral disease: evaluation of safety aNd efficAcy) study demonstrate a sustained treatment benefit with a novel sirolimus-eluting stent that also compares favorably to other femoropopliteal intervention trials. Head-to-head comparisons of NiTiDES with a paclitaxel-based DES are warranted. (The ILLUMINA Study [ILLUMINA]; NCT03510676).

Abstract P105: Bypasses To Below-Knee Arteries May Expedite Amputation In Patients With Claudication

Objective: Claudication is an early-stage subtype of peripheral artery disease that may result in surgical intervention. The purpose of this study was to compare the types of elective bypass in a population of Black and White patients with claudication and to identify actionable areas that may explain the higher limb amputation rates observed in Black patients. Methods: We identified Black and White patients undergoing elective infrainguinal bypass for claudication using data from the Vascular Quality Initiative registry (2011-2018). Distal bypass target was classified as 1) at or above the popliteal artery (above-knee) or 2) below the popliteal, including all tibial, peroneal, dorsalis pedis and tarsal/plantar arteries (below-knee). Graft conduit was categorized as vein or prosthetic. We calculated one-year risk of major lower limb amputation with 95% confidence intervals (CI) for all combinations of target and conduit, stratified by race. We then forced an intervention on the data to estimate the post-intervention incidence of amputation and the proportion of racial disparity eliminated and 95% CI if everyone received the gold standard treatment (above-knee, vein). Results: We identified 8,401 infrainguinal bypass revascularizations for claudication (12% Black/88% White); 82% were performed above-knee and 44% of those used a vein conduit. The remaining 18% of bypasses were to below-knee arteries, of which 78% used a vein conduit. The remaining 1,534 (18.3%) bypasses were to below-knee arteries, including 1,197 (78.4%) using vein and 330 (21.6%) using prosthetic material. One-year incidence of major limb amputation was 1.6% (1.3%,1.9%) among all grafts, 1.2% (1.0%,1.5%) in above-knee grafts, and 3.3% (2.4%,4.2%) in below-knee grafts. Black patients had higher incidence of amputation across bypass target/conduit groups compared to White patients; the difference was greatest for below-knee revascularizations (8.9%, 95% CI: 4.8%,12.3% v 2.1%, 95% CI: 0.9%,2.9%). Pre-intervention amputation incidence was 1.3% (1.0%,1.5%) in White patients and 3.6% (1.9%,5.2%) in Black patients. Overall amputation incidence decreased significantly after our gold standard intervention was applied for both White (1.0%; 0.7%,1.2%) and Black (2.0%; 0.7%,3.2%) patients. The risk difference (i.e. the disparity gap) between Black and White patients was lessened post-intervention by 56.8% (31.9%,116.3%). Conclusions: We observed risk of amputation higher than would be expected based on other studies of the natural history of claudication without bypass surgery; future work should identify the mechanisms that alter the natural history of claudication via open bypass surgery. Interventions below-knee or using a prosthetic graft were particularly harmful and their harm was concentrated in Black patients.

Feasibility of a Wireless Implantable Multi-electrode System for High-bandwidth Prosthetic Interfacing: Animal and Cadaver Study.

Currently used prosthetic solutions in upper extremity amputation have limited functionality, owing to low information transfer rates of neuromuscular interfacing. Although surgical innovations have expanded the functional potential of the residual limb, available interfaces are inefficacious in translating this potential into improved prosthetic control. There is currently no implantable solution for functional interfacing in extremity amputation which offers long-term stability, high information transfer rates, and is applicable for all levels of limb loss. In this study, we presented a novel neuromuscular implant, the the Myoelectric Implantable Recording Array (MIRA). To our knowledge, it is the first fully implantable system for prosthetic interfacing with a large channel count, comprising 32 intramuscular electrodes. The purpose of this study was to evaluate the MIRA in terms of biocompatibility, functionality, and feasibility of implantation to lay the foundations for clinical application. This was achieved through small- and large-animal studies as well as test surgeries in a human cadaver. We evaluated the biocompatibility of the system's intramuscular electromyography (EMG) leads in a rabbit model. Ten leads as well as 10 pieces of a biologically inert control material were implanted into the paravertebral muscles of four animals. After a 3-month implantation, tissue samples were taken and histopathological assessment performed. The probes were scored according to a protocol for the assessment of the foreign body response, with primary endpoints being inflammation score, tissue response score, and capsule thickness in µm. In a second study, chronic functionality of the full system was evaluated in large animals. The MIRA was implanted into the shoulder region of six dogs and three sheep, with intramuscular leads distributed across agonist and antagonist muscles of shoulder flexion. During the observation period, regular EMG measurements were performed. The implants were removed after 5 to 6 months except for one animal, which retained the implant for prolonged observation. Primary endpoints of the large-animal study were mechanical stability, telemetric capability, and EMG signal quality. A final study involved the development of test surgeries in a fresh human cadaver, with the goal to determine feasibility to implant relevant target muscles for prosthetic control at all levels of major upper limb amputation. Evaluation of the foreign body reaction revealed favorable biocompatibility and a low-grade tissue response in the rabbit study. No differences regarding inflammation score (EMG 4.60 ± 0.97 [95% CI 4.00 to 5.20] versus control 4.20 ± 1.48 [95% CI 3.29 to 5.11]; p = 0.51), tissue response score (EMG 4.00 ± 0.82 [95% CI 3.49 to 4.51] versus control 4.00 ± 0.94 [95% CI 3.42 to 4.58]; p > 0.99), or thickness of capsule (EMG 19.00 ± 8.76 µm [95% CI 13.57 to 24.43] versus control 29.00 ± 23.31 µm [95% CI 14.55 to 43.45]; p = 0.29) were found compared with the inert control article (high-density polyethylene) after 3 months of intramuscular implantation. Throughout long-term implantation of the MIRA in large animals, telemetric communication remained unrestricted in all specimens. Further, the implants retained the ability to record and transmit intramuscular EMG data in all animals except for two sheep where the implants became dislocated shortly after implantation. Electrode impedances remained stable and below 5 kΩ. Regarding EMG signal quality, there was little crosstalk between muscles and overall average signal-to-noise ratio was 22.2 ± 6.2 dB. During the test surgeries, we found that it was possible to implant the MIRA at all major amputation levels of the upper limb in a human cadaver (the transradial, transhumeral, and glenohumeral levels). For each level, it was possible to place the central unit in a biomechanically stable environment to provide unhindered telemetry, while reaching the relevant target muscles for prosthetic control. At only the glenohumeral level, it was not possible to reach the teres major and latissimus dorsi muscles, which would require longer lead lengths. As assessed in a combination of animal model and cadaver research, the MIRA shows promise for clinical research in patients with limb amputation, where it may be employed for all levels of major upper limb amputation to provide long-term stable intramuscular EMG transmission. In our study, the MIRA provided high-bandwidth prosthetic interfacing through intramuscular electrode sites. Its high number of individual EMG channels may be combined with signal decoding algorithms for accessing spinal motor neuron activity after targeted muscle reinnervation, thus providing numerous degrees of freedom. Together with recent innovations in amputation surgery, the MIRA might enable improved control approaches for upper limb amputees, particularly for patients with above-elbow amputation where the mismatch between available control signals and necessary degrees of freedom for prosthetic control is highest.