Streamlined Clinical Management Pathways May Reduce Major Amputations in Patients with Chronic Limb Threatening Ischaemia: A Prospective Cohort Study with Historical Controls.

OBJECTIVE: Patient characteristics and patterns of disease in chronic limb threatening ischaemia (CLTI) have changed markedly in recent years. Urgent specialist referral and timely revascularisation are recommended in international guidelines. UK guidelines now recommend revascularisation within 5 days of referral for inpatients and 2 weeks in outpatients. This study compared the contemporary one year major amputation incidence in patients with CLTI with a historical cohort at a single UK centre. METHODS: This was a single centre, observational cohort study with historical controls. A prospective cohort was recruited between May 2019 and March 2022. A historical cohort presenting between 2013 and 2015 inclusive was identified retrospectively. Significant changes in management pathways, including establishing a rapid access limb salvage clinic, occurred between these periods aiming to expedite time from referral to revascularisation. The one year primary outcome was major amputation, and the secondary outcome was death. Major amputation was analysed by Fine-Gray competing risks models (death as the competing risk), presented as subdistribution hazard ratios (SHRs). One year mortality was analysed by Cox regression, presented as hazard ratios. Analyses were adjusted for propensity score. RESULTS: A total of 928 patients were included (432 prospective and 496 historical). Proportions of patients presenting with tissue loss (72.2% vs. 71.6%; p = .090) were similar in both cohorts. At one year, 48 patients (11.1%) in the prospective cohort and 124 patients (25.0%) in the historical cohort had undergone a major amputation (p < .001). Risk of major amputation was 57.0% lower in the prospective cohort compared with the historical cohort after adjustment for propensity score (SHR 0.43, 95% confidence interval 0.29 - 0.63; p < .001). CONCLUSION: An encouraging reduction in major amputation incidence was observed after improvements to CLTI management pathways, but residual confounding is likely. The generalisability of these results is uncertain.

Does the Introduction of a Vascular Limb Salvage Service Improve One Year Amputation Outcomes for Patients with Chronic Limb-Threatening Ischaemia?

OBJECTIVE: Vascular limb salvage services are recommended by the Global Vascular Guidelines to help improve outcomes for patients with chronic limb-threatening ischaemia (CLTI), although their description within the literature is limited. This study reports the 12 month outcomes for an outpatient based vascular limb salvage (VaLS) clinic. METHODS: An analysis of a prospectively maintained database, involving all consecutive patients diagnosed with CLTI within the VaLS clinic from February 2018-February 2019, was undertaken. Data were compared with two comparator cohorts, identified from coding data: 1) patients managed prior to the clinic, between May 2017 and February 2018 (Pre-Clinic [PC]); and 2) patients managed outside of clinic, between February 2018 and February 2019 (Alternative Pathways [AP]). Freedom from major amputation at 12 months was the primary outcome. Kaplan-Meier plots and adjusted Cox's proportional hazard models (aHR) were used to compare outcomes. RESULTS: Five hundred and sixty-six patients (VaLS 158, AP 173, PC 235) were included (median age 74 years). Patients managed within the VaLS cohort were statistically significantly more likely to be free from major amputation (90.5%) compared with both the AP (82.1%, aHR 0.52, 95% confidence interval [CI] 0.28 - 0.98, p = .041) and the PC (80.0%; aHR 0.50, 95% CI 0.28 - 0.91, p = .022) cohorts at 12 months, after adjustment for age, disease severity, and presence of diabetes. CONCLUSION: This study supports the recommendations of the Global Vascular Guidelines that vascular limb salvage clinics may improve the rate of major amputation. Furthermore, the study provides a reproducible service model that delivers timely vascular assessment in an ambulatory setting. Further evaluation is required to assess longer term outcomes.

Leg ischaemia management collaboration (LIMb): study protocol for a prospective cohort study at a single UK centre.

INTRODUCTION: Severe limb ischaemia (SLI) is the end stage of peripheral arterial occlusive disease where the viability of the limb is threatened. Around 25% of patients with SLI will ultimately require a major lower limb amputation, which has a substantial adverse impact on quality of life. A newly established rapid-access vascular limb salvage clinic and modern revascularisation techniques may reduce amputation rate. The aim of this study was to investigate the 12-month amputation rate in a contemporary cohort of patients and compare this to a historical cohort. Secondary aims are to investigate the use of frailty and cognitive assessments, and cardiac MRI in risk-stratifying patients with SLI undergoing intervention and establish a biobank for future biomarker analyses. METHODS AND ANALYSIS: This single-centre prospective cohort study will recruit patients aged 18-110 years presenting with SLI. Those undergoing intervention will be eligible to undergo additional venepuncture (for biomarker analysis) and/or cardiac MRI. Those aged ≥65 years and undergoing intervention will also be eligible to undergo additional frailty and cognitive assessments. Follow-up will be at 12 and 24 months and subsequently via data linkage with NHS Digital to 10 years postrecruitment. Those undergoing cardiac MRI and/or frailty assessments will receive additional follow-up during the first 12 months to investigate for perioperative myocardial infarction and frailty-related outcomes, respectively. A sample size of 420 patients will be required to detect a 10% reduction in amputation rate in comparison to a similar sized historical cohort, with 90% power and 5% type I error rate. Statistical analysis of this comparison will be by adjusted and unadjusted logistic regression analyses. ETHICS AND DISSEMINATION: Ethical approval for this study has been granted by the UK National Research Ethics Service (19/LO/0132). Results will be disseminated to participants via scientific meetings, peer-reviewed medical journals and social media. TRIAL REGISTRATION NUMBER: NCT04027244.