Editor's Choice - The GermanVasc Score: A Pragmatic Risk Score Predicts Five Year Amputation Free Survival in Patients with Peripheral Arterial Occlusive Disease

A systematic review of the accuracy of prognostic tests and scoring systems for use in the Global Vascular Guidelines' PLAN concept for the treatment of chronic limb threatening ischemia

OBJECTIVE

The 2019 Global Vascular Guidelines recommend risk assessment for evidence based revascularization based on the acronym PLAN: Patient risk, Limb severity and ANatomical complexity of disease. This meta-analysis compares a multitude of prognostic tests within these categories.

METHODS

A systematic review and meta-analysis of tests that estimated 1-year major event (amputation-free survival and major adverse limb events) probability. Individual patient data were reconstructed from survival estimate curves. With presence or absence of major events, sensitivity, specificity, and area under receiver operating characteristics curves (AUC) were computed. Tests with an AUC ≥70%, or that correlated with revascularization feasibility were included. Practical application of tests was assessed to make a recommendation on PLAN implementation.

RESULTS

Ninety-six studies describing 77 unique predictive techniques were included, of which thirteen were sufficient. These 13 tests were divided in four Patient risk (5 studies), three Limb severity (3 studies), and six ANatomical complexity of disease (9 studies). Patient risk: Three tests were included: biochemical assessment of calprotectin and C-reactive protein, radiologic measurement of sarcopenia, and predictive score with the GermanVasc chronic limb-threatening ischemia (CLTI) score. These tests scored AUCs of 82.0%, 72.7%, and 71.8%, respectively, of which the GermanVasc CLTI score was deemed most applicable in clinical practice. Limb severity: The adjusted Wound Ischemia foot Infection score (WIfI) resulted as best predictive score (AUC, 78.8%), but due to the lack of external validation, the original WIfI score was deemed best applicable. ANatomical complexity of disease: No test surpassed 70% AUC for 1-year event estimation, and was correlated with feasibility of revascularization, the latter only being served by the Global Limb Anatomic Staging System.

CONCLUSIONS

In evidence-based revascularization in patients with CLTI according to the PLAN concept, we recommend to use GermanVasc, WIfI, and the Global Limb Anatomic Staging System.

Editor's Choice - Delays to Revascularisation and Outcomes of Non-Elective Admissions for Chronic Limb Threatening Ischaemia: a UK Population Based Cohort Study

OBJECTIVE

Major amputation and death are significant outcomes after lower limb revascularisation for chronic limb threatening ischaemia (CLTI), but there is limited evidence on their association with the timing of revascularisation. The aim of this study was to examine the relationship between time from non-elective admission to revascularisation and one year outcomes for patients with CLTI.

METHODS

This was an observational, population based cohort study of patients aged ≥ 50 years with CLTI admitted non-electively for infrainguinal revascularisation procedures in English National Health Service hospitals from January 2017 to December 2019 recorded in the Hospital Episode Statistics database. Outcomes were death and ipsilateral major amputation rate at one year. Logistic regression models were fitted to explore the relationship between time to revascularisation and death, adjusted for patient and admission factors. For major amputation, multinomial logistic regression models were used to account for the competing risk of death.

RESULTS

A total of 10 183 patients (median age 75 years) were included in the analysis, of which 67.1% (n = 6 831) were male and 57.6% had diabetes. In patients with tissue loss, the unadjusted one year mortality rate was 30.0% (95% confidence interval [CI] 28.9 - 31.0%), and for every one day increase in time from admission to revascularisation, the adjusted odds of one year death increased by 3% (odds ratio 1.03, 95% CI 1.02 - 1.04). In the absence of tissue loss, the unadjusted one year mortality rate was 19.9% (95% CI 18.4 - 21.4%) and there was no evidence of an association with time to revascularisation. There was also no statistically significant association between the time to revascularisation and risk of ipsilateral major amputation at one year irrespective of tissue loss.

CONCLUSION

Patients undergoing infrainguinal revascularisation during non-elective admissions for CLTI have high one year major amputation and mortality rates. Longer time from admission to revascularisation was independently associated with a higher mortality rate in patients with tissue loss, but not in those without.

Artificial Intelligence Techniques for Prognostic and Diagnostic Assessments in Peripheral Artery Disease: A Scoping Review

Peripheral artery disease (PAD) is a major public health concern worldwide, associated with high risk of mortality and morbidity related to cardiovascular and adverse limb events. Despite significant advances in both medical and interventional therapies, PAD often remains under-diagnosed, and the prognosis of patients can be difficult to predict. Artificial intelligence (AI) has brought a wide range of opportunities to improve the management of cardiovascular diseases, from advanced imaging analysis to machine-learning (ML)-based predictive models, and medical data management using natural language processing (NLP). The aim of this review is to summarize and discuss current techniques based on AI that have been proposed for the diagnosis and the evaluation of the prognosis in patients with PAD. The review focused on clinical studies that proposed AI-methods for the detection and the classification of PAD as well as studies that used AI-models to predict outcomes of patients. Through evaluation of study design, we discuss model choices including variability in dataset inputs, model complexity, interpretability, and challenges linked to performance metrics used. In the light of the results, we discuss potential interest for clinical decision support and highlight future directions for research and clinical practice.

The Comorbidity-Polypharmacy Score as a Predictive Tool of Survival and Limb Salvage in Patients Undergoing Lower Limb Revascularization Procedures for Chronic Limb-Threatening Ischemia

BACKGROUND

The comorbidity-polypharmacy score (CPPS) was created to evaluate the clinical burden of comorbidities in geriatric patients. It represents an objective tool to stratify patients' risk in different settings. The study aimed to evaluate CPPS in predicting mortality and amputation in patients undergoing elective revascularization procedures in chronic limb-threatening ischemia (CLTI) patients.

METHODS

This is a 2-year retrospective single-center study. We included all patients undergoing elective lower-limb revascularization procedures admitted with CLTI diagnosis. Four CPPS groups were defined: mild, moderate, severe, and morbid. The primary early and long-term outcomes were 30-day overall mortality, 30-day amputation rate, and overall survival and limb salvage, respectively.

RESULTS

A total of 442 patients were enrolled in the study. Mean age was 76.5 ± 9.9 years, and 61.5% (272/442) were male. CPPS was calculated: 22.6% (100/442) have mild CPPS, 54.3% (240/442) moderate, 21.9% (97/442) severe, and 1.2% (5/442) morbid. Kaplan-Meier curves for overall survival stratified by CPPS grade highlighted a strong statistically significant difference (P < 0.0001) among the 4 CPPS classes. Mild CPPS has a significantly higher limb salvage rate among moderate, severe, and morbid CPPS groups (P < 0.0001). Limb salvage for mild and severe CPPS, at 36 months was 95% vs. 85.1%, respectively. Stepwise multivariable Cox-analysis revealed that mortality was independently associated with dialysis, Rutherford Classification V, age, and CPPS. Male sex, multilevel arterial disease, and hybrid surgical repair were independently associated with amputations.

CONCLUSIONS

CPPS is a straightforward tool to evaluate the patient's complexity and could be used as an adjuvant tool to stratify early- and long-term outcomes in CLTI patients undergoing elective revascularization procedures.

Patients with chronic limb-threatening ischemia: Experiences of their disease, treatment, and care in a cross-sectoral setting. A scoping review

INTRODUCTION

Patients facing chronic limb-threatening ischemia (CLTI) experience significant burdens, impacting their physical, emotional, and social well-being. They require extensive care from multidisciplinary healthcare professionals across primary and secondary settings. Managing CLTI necessitates strict patient adherence to treatment protocols to prevent severe complications. Surprisingly, previous studies have overlooked these patients' unique perspectives, highlighting the need to explore their experiences and challenges.

OBJECTIVE

The objective of this review was to systematically identify, examine, and conceptually map extant literature on patients with CLTI in the context of living with the condition, and explore their experiences of receiving treatment and care within a cross-sectoral setting.

METHODS

A systematic search was completed on 18 September 2023 with no methodological or format restrictions. We identified the population, concept, and context to pinpoint the delineate the focus of this review process. The JBI methodology for scoping reviews and the PRISMA-ScR checklist were followed.

RESULTS

Based on our search, we found ten relevant scientific qualitative and/or quantitative sources and one non-scientific source. We identified four main maps: 1) Dependency on others is my new life condition, 2) I'm more than the sum of my conditions, 3) I'm lost in chaos, be alert to all of me, and 4) Give me more time, my body and mind are under attack.

CONCLUSION

This scoping review describes how patients' lives are affected by CLTI and provides insights into their perception of shared decision-making, treatment, and care. The review reveals the need for a more person-centered approach to care. To nuance person-centred care further, it is necessary to consider the impact of patients' cultural values and preferences. However, this area is marked by a notable research gap.

Machine Learning in Vascular Medicine: Optimizing Clinical Strategies for Peripheral Artery Disease

Purpose of Review

Peripheral Artery Disease (PAD), a condition affecting millions of patients, is often underdiagnosed due to a lack of symptoms in the early stages and management can be complex given differences in genetic and phenotypic characteristics. This review aims to provide readers with an update on the utility of machine learning (ML) in the management of PAD.

Recent Findings

Recent research leveraging electronic health record (EHR) data and ML algorithms have demonstrated significant advances in the potential use of automated systems, namely artificial intelligence (AI), to accurately identify patients who might benefit from further PAD screening. Additionally, deep learning algorithms can be used on imaging data to assist in PAD diagnosis and automate clinical risk stratification.ML models can predict major adverse cardiovascular events (MACE) and major adverse limb events (MALE) with considerable accuracy, with many studies also demonstrating the ability to more accurately risk stratify patients for deleterious outcomes after surgical intervention. These predictions can assist physicians in developing more patient-centric treatment plans and allow for earlier, more aggressive management of modifiable risk-factors in high-risk patients. The use of proteomic biomarkers in ML models offers a valuable addition to traditional screening and stratification paradigms, though clinical utility may be limited by cost and accessibility.

Summary

The application of AI to the care of PAD patients may enable earlier diagnosis and more accurate risk stratification, leveraging readily available EHR and imaging data, and there is a burgeoning interest in incorporating biological data for further refinement. Thus, the promise of precision PAD care grows closer. Future research should focus on validating these models via real-world integration into clinical practice and prospective evaluation of the impact of this new care paradigm.

Combining electronic health records data from a clinical research network with registry data to examine long-term outcomes of interventions and devices: an observational cohort study

OBJECTIVES

To assess the feasibility of assessing long-term outcomes of peripheral vascular intervention (PVI) by linking data from a clinical registry to electronic health records (EHR) data from a clinical research network.

DESIGN

Observational cohort study.

SETTING

Vascular Quality Initiative registry linked to INSIGHT Clinical Research Network, which aggregated EHR data from multiple institutions in New York City.

PARTICIPANTS

Patients receiving PVI during 1 January 2013-30 November 2021 in four centres in New York City.

PRIMARY AND SECONDARY OUTCOME MEASURES

We examined the proportion of registry patients retained in EHR over time and predictors of EHR retention after year 1. We evaluated the implications of EHR attrition by examining amputation-free survival (AFS) in the observed data and predicted data when patients discontinued in the EHR were hypothesised to have increased risks of events than the observed average.

RESULTS

We included 1405 patients receiving PVI (age=70.8±11.2 years, 51.3% male). Among eligible patients, 75.2% were retained in EHR through year 3. Patients who aged 75 years or above (vs <65: OR 0.34, 95% CI 0.18 to 0.62), had Medicaid (vs Medicare: OR 0.41, 95% CI 0.22 to 0.79), congestive heart failure (OR 0.54, 95% CI 0.32 to 0.90), dialysis (OR 0.47, 95% CI 0.24 to 0.91) and reduced ambulation (OR 0.34, 95% CI 0.15 to 0.75) were less likely to be retained in EHR. When discontinued patients were hypothesised to have increased risks of death or amputation than observed, AFS estimates diverged from the observed data around 6-12 months.

CONCLUSIONS

Studies using registry-EHR data may benefit from the timeliness of the data but may be most appropriate to focus on short-term to intermediate-term outcomes of interventions and devices. Future research is needed to investigate the value of registry-EHR linkage in facilitating short-term to intermediate-term outcome assessment following vascular interventions and advanced statistical approaches to account for non-random missing long-term data.

Development and evaluation of a prediction model for peripheral artery disease-related major adverse limb events using novel biomarker data

OBJECTIVE

Prognostic tools for individuals with peripheral artery disease (PAD) remain limited. We developed prediction models for 3-year PAD-related major adverse limb events (MALE) using demographic, clinical, and biomarker data previously validated by our group.

METHODS

We performed a prognostic study using a prospectively recruited cohort of patients with PAD (n = 569). Demographic/clinical data were recorded including sex, age, comorbidities, previous procedures, and medications. Plasma concentrations of three biomarkers (N-terminal pro-B-type natriuretic peptide [NT-proBNP], fatty acid binding protein 3 [FABP3], and FABP4) were measured at baseline. The cohort was followed for 3 years. MALE was the primary outcome (composite of open/endovascular vascular intervention or major amputation). We trained three machine learning models with 10-fold cross-validation using demographic, clinical, and biomarker data (random forest, decision trees, and Extreme Gradient Boosting [XGBoost]) to predict 3-year MALE in patients. Area under the receiver operating characteristic curve (AUROC) was the primary model evaluation metric.

RESULTS

Three-year MALE was observed in 162 patients (29%). XGBoost was the top-performing predictive model for 3-year MALE, achieving the following performance metrics: AUROC = 0.88 (95% confidence interval [CI], 0.84-0.94); sensitivity, 88%; specificity, 84%; positive predictive value, 83%; and negative predictive value, 91% on test set data. On an independent validation cohort of patients with PAD, XGBoost attained an AUROC of 0.87 (95% CI, 0.82-0.90). The 10 most important predictors of 3-year MALE consisted of: (1) FABP3; (2) FABP4; (3) age; (4) NT-proBNP; (5) active smoking; (6) diabetes; (7) hypertension; (8) dyslipidemia; (9) coronary artery disease; and (10) sex.

CONCLUSIONS

We built robust machine learning algorithms that accurately predict 3-year MALE in patients with PAD using demographic, clinical, and novel biomarker data. Our algorithms can support risk stratification of patients with PAD for additional vascular evaluation and early aggressive medical management, thereby improving outcomes. Further validation of our models for clinical implementation is warranted.

Adherence and Persistence to Antiplatelet Therapy in Lower Extremity Peripheral Arterial Disease: A Danish Population Based Cohort Study

OBJECTIVE

Adherence to antiplatelet therapy is recommended but unexplored in patients with symptomatic lower extremity peripheral arterial disease (PAD). Therefore, this study aimed to determine adherence and persistence to antiplatelet therapy in patients with PAD, defined as intermittent claudication and chronic limb threatening ischaemia.

DESIGN

Population based nationwide cohort study.

METHODS

This study included all Danish citizens aged ≥ 40 years with a first inpatient or outpatient diagnosis of symptomatic PAD between 2010 - 2017, and who had at least one prescription claim for aspirin and/or clopidogrel within 90 days after diagnosis. Adherence was determined by the proportion of days covered (PDC) during the first year after diagnosis. Persistence was defined as no treatment gap ≥ 30 days between prescription renewals over three year follow up.

RESULTS

A total of 39 687 patients were eligible for inclusion, of whom 23 279 (58.7%) claimed a prescription for aspirin and/or clopidogrel within 90 days of diagnosis. Among these, 12 898 (55.4%) were prevalent users, while the remainder comprised new users who initiated the therapy after the index PAD diagnosis. The mean PDC was 74.5% (SD 35.0%) for prevalent users and 60.5% (SD 30.5%) for new users. Adherence increased with age and number of concomitant drugs. The overall one year cumulative incidence treatment discontinuation was 13.0% (95% CI 12.5 - 13.4%) overall, 17.2% (CI 16.6 - 17.9%) for prevalent users, and 7.9% (CI 7.4 - 8.4%) for new users. At three year follow up, the cumulative incidence of discontinuation was 31.5% (CI 30.9 - 32.2%) overall, 44.6% (CI 43.7 - 45.4%) for prevalent users, and 14.6% (CI 13.9 - 15.3) for new users.

CONCLUSION

Less than 60% of patients with newly diagnosed symptomatic PAD claimed a prescription for antiplatelet therapy within 90 days of diagnosis, and both adherence and persistence were moderate during the first year after diagnosis. These findings underscore the importance of efforts to improve the initiation and continuation of antiplatelet therapy in patients with PAD.

Awareness of smoking cessation amongst German vascular surgeons

Background: Smoking represents the well-known enemy of vascular well-being. Numerous previous studies emphasised the important role of smoking on the development and progression of atherosclerotic cardiovascular disease. The current study aimed to identify hurdles and barriers for an insufficient implementation of secondary prevention in the treatment of lower extremity peripheral arterial disease (PAD). Methods: All members of the German Society for Vascular Surgery and Vascular Medicine (DGG) with valid email addresses were invited to participate in an electronic survey on smoking. Results are descriptively presented. Results: Amongst 2716 invited participants, 327 (12%) submitted complete responses, thereof 33% women and 80% between 30 and 59 years old (87% board certified specialists). 83% were employed by hospitals (56% teaching hospital, 14% university, 13% non-academic) and 16% by outpatient facilities. 6% are active smokers (63% never) while a mean of five medical education activities on smoking cessation were completed during the past five years of practice. Only 27% of the institutions offered smoking cessation programs and 28% of the respondents were aware of local programs while a mean of 46% of their patients were deemed eligible for participation. 63% of the respondents deemed outpatient physicians primarily responsible for smoking cessation, followed by medical insurance (26%). Conclusions: The current nationwide survey of one scientific medical society involved in the care of patients with vascular disease revealed that smoking cessation, although being commonly accepted as important pillar of comprehensive holistic care, is not sufficiently implemented in everyday clinical practice.

Exercise Training for Patients With Peripheral Arterial Occlusive Disease

BACKGROUND

One-third of all persons with peripheral arterial occlusive disease (PAOD) suffer from intermittent claudication. Exercise training under appropriate supervision is recommended in the pertinent guidelines, but physicians order it too rarely, and so-called vascular exercise groups are not available everywhere. This situation needs improvement in view of the impor - tance of walking ability and cardiorespiratory fitness for patients' quality of life and long-term disease outcome.

METHODS

We review the scientific evidence on exercise training and on ways to lower barriers to the ordering of exercise training and to patient participation, on the basis of pertinent articles retrieved by a search of PubMed and in specialized sports science journals.

RESULTS

10 meta-analyses, 12 randomized controlled trials (RCTs), and 7 cohort studies were considered for this review. Largescale cohort studies have shown that exercise is associated with a lower risk of death (relative risk 0.65-0.78 after 12 months of exercise training, compared to an inactive lifestyle). Exercise training also improves the maximal walking distance by a mean of 136 m (training at home) or 180-310 m (supervised training). An additional improvement by a mean of 282 m can be expected from a combination of exercise training and endovascular revascularization. Further behavior-modifying interventions, such as goal-setting, planning, and feedback, increase both the maximum walking distance and the weekly duration of exercise.

CONCLUSION

Exercise improves walking ability and lowers mortality. To attract patients with intermittent claudication to exercise training, a broad assortment of analog, digital and telemetric tools and a dense network of vascular exercise groups should be made available, along with regular contact between physicians and patients.

Epidemiological Trends and Projections of Incidence, Prevalence, and Disease Related Mortality Associated With Peripheral Arterial Disease: Observations Using Nationwide Danish Data

OBJECTIVE

Peripheral arterial disease (PAD) trends remain unclear because contemporary data are sparse and conflicting. This nationwide cohort study quantified changes in PAD incidence, prevalence, and all cause mortality, and projected prevalence development through to 2040.

METHODS

Population based registries covering the entire Danish population aged ≥ 40 years from 2000 to 2018 were linked to assess trends in PAD incidence, prevalence, and all cause mortality, overall and by sex and age groups. Based on observed trends in incidence and mortality, and estimated future annual age distribution and population mortality, the PAD prevalence through to 2040 was projected.

RESULTS

The Danish population aged 40 - 99 years in 2000 - 2018 included 4 811 281 individuals, among whom 145 870 incident PAD diagnoses were identified. The age and sex standardised PAD incidence decreased from 2.26 per 1 000 person years in 2000 to 1.65 in 2018 (incidence RR 0.74, 95% CI 0.72 - 0.77). The incidence was approximately 20% higher in men than women but declined similarly over time. Concurrently, PAD prevalence in the Danish adult population increased from 1.3% to 1.6% (prevalence ratio 1.28, 95% CI 1.26 - 1.30). Among patients aged ≥ 80 years, the prevalence reached 5.7% in women and 7.9% in men. The age and sex standardised annual mortality among patients with PAD decreased from 9.8% in 2000 to 7.2% in 2018 (mortality ratio 0.75, 95% CI 0.72 - 0.78). Projections of PAD prevalence demonstrated that the rising PAD prevalence will continue until around 2030, followed by a decline towards 2040. Among individuals aged ≥ 80 years, the prevalence was projected to plateau at 8.9% for men and 6.2% for women before declining.

CONCLUSION

Within an unselected nationwide population, the incidence and all cause mortality of PAD have declined over the last two decades. Concurrently, prevalence increased and is projected to increase further over the coming decade, emphasising the growing burden of this common atherosclerotic disease in ageing populations.

Editor's Choice - Long Term Outcomes After Invasive Treatment of Carotid Artery Stenosis: a Longitudinal Study of German Health Insurance Claims

OBJECTIVE

There is a paucity of observational data including long term outcomes after invasive treatment for carotid artery stenosis.

METHODS

This retrospective study used nationwide insurance claims from the third largest provider in Germany, DAK-Gesundheit. Patients who underwent inpatient carotid endarterectomy (CEA) or carotid artery stenting (CAS) between 1 January 2008 and 31 May 2017 were included. The Elixhauser comorbidity scores from longitudinally linked hospital episodes were used. Kaplan-Meier analysis and the log rank test were used to determine long term stroke free survival. Multivariable regression models were developed to adjust for confounding.

RESULTS

A total of 22 637 individual patients (41.6% female, median age 72.5 years) were included, of whom 15 005 (66.3%) were asymptomatic and 17 955 (79.3%) underwent CEA. After a median of 48 months, 5 504 any stroke or death events were registered. The mortality rate varied between 0.4% (CEA for asymptomatic stenosis) and 2.1% (urgent CAS for acute stroke patients) at 30 days, and between 4.1% and 8.4% at one year, respectively. The rate for any stroke varied between 0.6% (CEA for asymptomatic stenosis) and 2.5% (CAS for symptomatic patients) at 30 days, and between 2.5% and 6.4% at one year, respectively. The combined rate for any stroke and mortality at one year was 6.3% (CEA for asymptomatic stenosis), 8.7% (CAS for asymptomatic stenosis), and 12.5% (urgent CAS for acute stroke patients). After five years, the overall stroke rate was 7.4% after CEA and 9.0% after CAS. In adjusted analyses, both older age and van Walraven comorbidity score were associated with events, while treatment of asymptomatic stenosis was associated with lower event rates.

CONCLUSION

The current study revealed striking differences between previous landmark trials and real world practice. It further suggested excess deaths among invasively treated asymptomatic patients.

Immunologic profiles in patients with chronic limb-threatening ischemia undergoing endovascular revascularization

BACKGROUND

Inflammation and immune dysregulation have been associated with adverse outcomes in cardiovascular disease. There is limited understanding of the association of different profiles of white blood cell (WBC) subsets and red cell distribution width (RDW) in patients with chronic limb-threatening ischemia (CLTI).

METHODS

Patients with CLTI undergoing endovascular revascularization in our single-center, tertiary care hospital from 2017 to 2019, who had a preceding complete blood count (CBC) with WBC differentials (n =213), were included in the analysis. Patient characteristics, laboratory values, and clinical outcomes were collected. Cox proportional hazards regression models were used to assess for associations between all-cause mortality and leukocyte subset; multivariate analysis was used to account for confounders. Kaplan-Meier curves were generated to depict survival censored at 1 year postrevascularization using baseline CBC indices.

RESULTS

Adjusting for confounders, elevated RDW was associated with increased mortality (continuous per % increase, adjusted hazard ratio [HR] 1.33, p < 0.001). Baseline lymphopenia was associated with mortality in univariate analysis. Other leukocyte subtypes were not associated with mortality outcomes in our population. Exploratory analysis showed negative deflections in ∆WBC from pre- to postprocedure day 1 were affiliated with increased mortality when adjusted for age, sex, race, chronic kidney disease, and baseline hemoglobin (∆WBC HR 1.16, p = 0.004). Further exploratory analysis showed an association between RDW and all-comers readmission.

CONCLUSIONS

The utilization of a periprocedural WBC subset differential can be a useful adjunct to risk-stratify patients with CLTI undergoing endovascular revascularization. Further studies are needed to understand potential ways to modulate immune dysregulation so as to improve mortality outcomes.

Five Year Survival in Medicare Patients Undergoing Interventions for Peripheral Arterial Disease: a Retrospective Cohort Analysis of Linked Registry Claims Data

OBJECTIVE

To justify the up front risks of offering elective interventions for intermittent claudication (IC), patients should have reasonable life expectancy to derive durable clinical benefits. Open surgery for chronic limb threatening ischaemia (CLTI) is maximally beneficial in patients surviving ≥ 2 years. The aim was to assess long term survival after IC and CLTI interventions.

METHODS

In a retrospective cohort analysis, the Vascular Quality Initiative (VQI) registry from 1 January 2010 to 31 May 2021 was queried for peripheral vascular intervention (PVI), infra-inguinal bypasses (IIB), and supra-inguinal bypasses (SIB) for IC and CLTI across 286 US centres. VQI linkage to Medicare insurance claims provided five year survival data. Multivariable analysis identified factors associated with five year mortality.

RESULTS

There were 31 457 PVIs (44.7% IC, 55.3% CLTI), 7 978 IIBs (26.9% IC, 73.1% CLTI), and 2 149 SIBs (50.1% IC, 49.9% CLTI) recorded in the VQI. Among the PVI, IIB, and SIB cohorts, average ages were 75, 73, and 72 years, respectively. Respective five year mortality after PVI for IC and CLTI was 37.2% and 71.1%; after IIB for IC and CLTI it was 37.8% and 60%; and after SIB for IC and CLTI it was 33.8% and 53.8%. On multivariable analysis, across all procedures, end stage renal disease, CLTI, congestive heart failure, anaemia, chronic obstructive pulmonary disease, and prior amputation were independently associated with increased mortality. Pre-admission home living and pre-operative aspirin use were independently associated with decreased mortality.

CONCLUSION

Long term survival in Medicare patients undergoing interventions in VQI centres for peripheral arterial disease is poor. Two thirds of CLTI patients and over one third of IC patients were not alive at five years. Intervening for IC in patients with high mortality risk should be avoided. For CLTI patients identified with decreased survival likelihood, intervention durability may be less important than invasiveness. Pre-operative medical optimisation should always be undertaken.

Artificial intelligence for the vascular surgeon

In recent years, artificial intelligence (AI) has permeated different aspects of vascular surgery to solve challenges in clinical practice. Although AI in vascular surgery is still in its early stages, there have been promising developments in its applications to vascular diagnosis, risk stratification, and outcome prediction. By establishing a baseline knowledge of AI, vascular surgeons are better equipped to use and interpret the data from these types of projects. This review aims to provide an overview of the fundamentals of AI and highlight its role in helping vascular surgeons overcome the challenges of clinical practice. In addition, we discuss the limitations of AI and how they affect AI applications.

Best medical treatment in patients with PAD

Background: Guidelines recommend comprehensive lifestyle change in patients with peripheral arterial disease (PAD) to prevent cardiovascular events and death. When compared with other populations, patients with PAD are less likely to receive best medical therapies (BMT). The aim of this pilot study was to integrate all aspects of BMT in an intervention program and to determine the feasibility of such an approach by highlighting strengths and obstacles of a multi-aspect intervention. Patients and methods: Patients consecutively hospitalized due to symptomatic PAD between 01 December 2021 and 28 February 2022 were included and followed for ten weeks. We randomized into a lifestyle intervention (education on BMT, a list of regional contact data for supervised exercise, weekly counselling by phone for ten times) vs. standard of care (one contact to talk about BMT). Vascular Quality of Life Questionnaire - 6 (VascuQoL-6) was used to collect patient reported outcomes. Results: Of 50 eligible patients 40 agreed to participate (32.5% female, 72.5 years in mean). During follow-up nine patients dropped out (4 in intervention group vs. 5). As for risk factor modification one patient was able to reach a normal weight body-mass-index (BMI) and nine reduced weight. Two patients stopped smoking, three reduced their consumption. The reported adherence to medication was a hundred percent. No patient attended supervised exercise therapy but eight trained at a home-based setting according to guidelines. The mean score of VascuQoL-6 at follow-up was higher in the intervention group compared to the control group (17.4 vs. 13.8 points) at last contact with both groups increasing from baseline. Conclusions: This pilot study followed 40 patients for up to 10 weeks after inpatient treatment while we randomized a multi-aspect lifestyle intervention versus standard of care. Thereby, the current study illustrated the numerous obstacles and provided pragmatic solutions for the planning of studies on BMT in this target population.

Nationwide Study in France To Predict One Year Major Bleeding and Validate the OAC3-PAD Score in Patients Undergoing Revascularisation for Lower Extremity Arterial Disease

OBJECTIVE

Antithrombotic strategies are currently recommended for the treatment of lower extremity artery disease (LEAD) but specific scores to assess the risk of bleeding in these patients are scarce. To fill the gap, the OAC3-PAD bleeding score was recently developed and validated in German cohorts. The aim of this study was to determine whether this score performs appropriately in another real world nationwide cohort.

METHODS

This 10 year retrospective, multicentre study based on French national electronic health data included patients who underwent revascularisation for LEAD between January 2013 and June 2022. The OAC3-PAD score was calculated and from this, the population was classified into four groups: low, low to moderate, moderate to high and high risk. A binary logistic regression model was applied, with major bleeding occurring at one year (defined using the International Classification of Diseases ICD-10) as the dependent variable. The performance of the OAC3-PAD bleeding score was investigated using a receiver operating characteristic curve.

RESULTS

Among 161 205 patients hospitalised for LEAD treatment in French institutions, the one year incidence of major bleeding was 13 672 patients (8.5%). The distribution of the population according to the OAC3-PAD bleeding score was: 88 835 patients (55.1%), 34 369 (21.3%), 27 914 (17.3%), and 10 087 (6.3%) in the low, low to moderate, moderate to high, and high risk groups, respectively; with an incidence of one year major bleeding of 5.0%, 9.8%, 13.2%, and 21.3%. The OAC3-PAD model achieved an AUC of 0.650 to predict one year major bleeding following LEAD repair (95% CI 0.645 - 0.655), with a sensitivity of 0.67 and a specificity of 0.57.

CONCLUSION

This nationwide analysis confirmed the accuracy of the OAC3-PAD model to predict one year major bleeding and served as external validation. Although further studies are required, it adds evidence and perspectives to further generalise its use to guide the management of patients with LEAD.

A prospective survey study on the education and awareness about walking exercise amongst inpatients with symptomatic peripheral arterial disease in Germany

Background: To determine the adherence to supervised exercise training and underlying reasons for non-adherence amongst patients with inpatient treatment of symptomatic lower extremity peripheral arterial disease (PAD). Patients and methods: This was a prospective questionnaire-based survey study of all consecutively treated inpatients with treatment for either intermittent claudication or chronic limb-threatening ischaemia (CLTI) surveyed at sixteen participating centres in Germany. Results: A total of 235 patients (median age 70 years) were included, thereof 29.4% females and 34.6% with CLTI. The median time from first PAD diagnosis was 4 years (IQR: 1-8). Only 11.4% have previously participated in any walking exercise programme before the index treatment, thereby 10.0% in the IC subgroup and 12.0% with CLTI. Amongst all patients, 35.6% responded they were appropriately informed about the necessity and benefits of walking exercise programmes by their hospital physicians (25.8% by general practitioners), and 65.3% agreed that adherence to supervised exercise may improve their pain-free walking distance. A total of 24.5% responded they had access to necessary information concerning local walking exercise programmes. Amongst 127 free text comments on the reasons for non-adherence to supervised exercise training, 64% of the comments contained lack of information or consent on such measures. Conclusions: Less than 12% of the patients enrolled in the current study have ever participated in a walking exercise programme during their life course. Although all practice guidelines contain corresponding class I recommendations, especially for patients suffering from IC, most patients responded that they were not appropriately informed about the necessity of exercise training along with the fact that 65% agreed that exercise may increase the pain-free walking distance. Taken all together, these results emphasise that we miss an important opportunity in the patient-physician communication. Efforts should be made to improve acceptance and application of structured walking-exercise for patients with PAD.

Application of machine learning algorithms in electronic medical records to predict amputation-free survival after first revascularization in patients with peripheral artery disease

BACKGROUND

This study aimed to apply eight machine learning algorithms to develop the optimal model to predict amputation-free survival (AFS) after first revascularization in patients with peripheral artery disease (PAD).

METHODS

Among 2130 patients from 2011 to 2020, 1260 patients who underwent revascularization were randomly assigned to training set and validation set in an 8:2 ratio. 67 clinical parameters were analyzed by lasso regression analysis. Logistic regression, gradient boosting machine, random forest, decision tree, eXtreme gradient boosting, neural network, Cox regression, and random survival forest (RSF) were applied to develop prediction models. The optimal model was compared with GermanVasc score in testing set comprising patients from 2010.

RESULTS

The postoperative 1/3/5-year AFS were 90%, 79.4%, and 74.1%. Age (HR:1.035, 95%CI: 1.015-1.056), atrial fibrillation (HR:2.257, 95%CI: 1.193-4.271), cardiac ejection fraction (HR:0.064, 95%CI: 0.009-0.413), Rutherford grade ≥ 5 (HR:1.899, 95%CI: 1.296-2.782), creatinine (HR:1.03, 95%CI: 1.02-1.04), surgery duration (HR:1.03, 95%CI: 1.01-1.05), and fibrinogen (HR:1.292, 95%CI: 1.098-1.521) were independent risk factors. The optimal model was developed by RSF algorithm, with 1/3/5-year AUCs in training set of 0.866 (95% CI:0.819-0.912), 0.854 (95% CI:0.811-0.896), 0.844 (95% CI:0.793-0.894), in validation set of 0.741 (95% CI:0.580-0.902), 0.768 (95% CI:0.654-0.882), 0.836 (95% CI:0.719-0.953), and in testing set of 0.821 (95%CI: 0.711-0.931), 0.802 (95%CI: 0.684-0.919), 0.798 (95%CI: 0.657-0.939). The c-index of the model outperformed GermanVasc Score (0.788 vs 0.730). A dynamic nomogram was published on shinyapp (https://wyy2023.shinyapps.io/amputation/).

CONCLUSION

The optimal prediction model for AFS after first revascularization in patients with PAD was developed by RSF algorithm, which exhibited outstanding prediction performance.

The Independent Impact of Peripheral Arterial Disease on Mortality in Nonagenarians and Centenarians Who Were Treated in an Intensive Care Unit: A Consecutive Cohort of 1 108 Patients

OBJECTIVE

To investigate the clinical characteristics, risk factors, and outcomes of inpatients with peripheral arterial disease (PAD) including lower extremity PAD, abdominal aortic aneurysm (AAA), and carotid artery disease in a large cohort of critically ill patients aged ≥ 90 years.

METHODS

A retrospective analysis was conducted of all adult patients aged ≥ 90 years consecutively admitted to the intensive care unit at a tertiary care centre in Hamburg, Germany, between 1 January 2008 and 30 April 2019. Multivariable regression and Kaplan-Meier methods were used to determine the independent impact of PAD on short and long term mortality endpoints. The analyses were adjusted for confounding by several sociodemographic and clinical parameters including Charlson Comorbidity Index (CCI) and established clinical risk scores.

RESULTS

A total of 1 108 eligible patients were identified (92.3 years, 33% men). Of these, 24% had PAD (9% lower extremity PAD, 2% AAA, 15% coronary artery disease) and 76% did not have any history of PAD and were used as a comparison group. When compared with the comparison group, patients with PAD had a higher CCI (2 vs. 1, p < .001), more often had chronic kidney disease (28% vs. 21%, p = .019), and renal replacement therapy (5% vs. 2%, p = .016). Furthermore, they needed vasopressors (48% vs. 40%, p = .027) and parenteral nutrition (10% vs. 6%, p = .041) more often. After adjusting for confounding, PAD was independently associated with increased in hospital (hazard ratio [HR] 1.97, 95% confidence interval [CI] 1.39 - 2.81, p < .001) and long term mortality rates (HR 1.32, 95% CI 1.05 - 1.66, p = .019).

CONCLUSION

One of four critically ill nonagenarians and centenarians in an ICU in Germany had PAD. PAD was associated with both higher short and long term mortality rates while its impact outweighed higher age. Future studies should address this increasingly important population beyond 89 years of age.

Performance of the Emergency Surgery Score (ESS) for nonelective infrainguinal open revascularization procedures (NEIOR)

BACKGROUND

The Emergency Surgery Score has been previously validated as a reliable; tool to predict postoperative outcomes in emergency general surgery. The purpose of this study was to assess the performance of the Emergency Surgery Score for infrainguinal open revascularization procedures in the nonelective setting.

METHODS

The American College of Surgeons' National Surgical Quality Improvement Program database was retrospectively analyzed for patients undergoing infrainguinal open revascularization procedures in the nonelective setting between 2015 and 2019. The performance of the Emergency Surgery Score in predicting mortality in each procedure was assessed using receiver operating characteristic analyses.

RESULTS

A total of 5,027 patients underwent infrainguinal open revascularization procedures in the nonelective setting with median age 68 (±11.66 standard deviation), with 1,666 females (33.1%). The 30-day mortality rate was 2.7%. The Emergency Surgery Score correlated with 30-day mortality (area under the curve was 0.738). The Emergency Surgery Score also predicted risk of death/discharge to hospice (area under the curve 0.756), discharge to rehab (area under the curve 0.643), renal failure (area under the curve 0.741), postintervention ventilation requirement (0.684), stroke (0.717), cardiopulmonary arrest (0.657), and septic shock (0.697). A cumulative frequency table of mortality with Emergency Surgery Score was used to partition patients into quartiles of Emergency Surgery Score ≤5, Emergency Surgery Score of 6, Emergency Surgery Score of 7 or 8, and Emergency Surgery Score ≥9. A Cochran-Armitage test showed linear trend toward increased 30-day mortality among the quartiles with increasing Emergency Surgery Score (P < .001), with quartile 4 (Emergency Surgery Score ≥10) having 13 times odds of increased 30-day mortality compared to reference quartile 1 (Emergency Surgery Score ≤4).

CONCLUSION

Emergency Surgery Score performance accurately predicts mortality for infrainguinal open revascularization procedures in the nonelective setting procedures. It may be useful for preoperative risk stratification and for national benchmarking after nonelective open lower extremity procedures.

Applications of artificial intelligence for patients with peripheral artery disease

OBJECTIVE

Applications of artificial intelligence (AI) have been reported in several cardiovascular diseases but its interest in patients with peripheral artery disease (PAD) has been so far less reported. The aim of this review was to summarize current knowledge on applications of AI in patients with PAD, to discuss current limits, and highlight perspectives in the field.

METHODS

We performed a narrative review based on studies reporting applications of AI in patients with PAD. The MEDLINE database was independently searched by two authors using a combination of keywords to identify studies published between January 1995 and December 2021. Three main fields of AI were investigated including natural language processing (NLP), computer vision and machine learning (ML).

RESULTS

NLP and ML brought new tools to improve the screening, the diagnosis and classification of the severity of PAD. ML was also used to develop predictive models to better assess the prognosis of patients and develop real-time prediction models to support clinical decision-making. Studies related to computer vision mainly aimed at creating automatic detection and characterization of arterial lesions based on Doppler ultrasound examination or computed tomography angiography. Such tools could help to improve screening programs, enhance diagnosis, facilitate presurgical planning, and improve clinical workflow.

CONCLUSIONS

AI offers various applications to support and likely improve the management of patients with PAD. Further research efforts are needed to validate such applications and investigate their accuracy and safety in large multinational cohorts before their implementation in daily clinical practice.

Evaluation of the ICD-10 system in coding revascularisation procedures in patients with peripheral arterial disease in England: A retrospective cohort study using national administrative and clinical databases

BACKGROUND

Many studies evaluating care in hospitals in England use the Hospital Episode Statistics (HES) administrative database. The aim of this study was to explore whether the International Classification of Diseases 10th Revision (ICD-10) system used by HES supported the evaluation of care received by patients with peripheral arterial disease (PAD) who had revascularisation.

METHODS

This retrospective cohort study used records on patients who had revascularisation for PAD between 1st January 2017 and 31st December 2019 in England, collected prospectively in the National Vascular Registry (NVR) and linked to HES. Patients were excluded if their NVR record did not have a match in HES, due to lack of consent or different admission and procedure dates. Agreement between different presentations of PAD recorded in the NVR and the ICD-10 diagnostic codes recorded in HES was evaluated using the unweighted Kappa statistic and sensitivity and specificity. Agreement between the NVR and HES was also assessed for gender, age, comorbidities, mode of admission, and procedure type and side.

FINDINGS

In total, 20,603 patients who had 24,621 admissions were included in the study. Agreement between NVR and HES on patient gender (Kappa = 0.98), age (Kappa = 0.98), mode of admission (Kappa = 0.80), and procedure type and side (Kappa = 0.92 and 0.87, respectively) was excellent. When all diagnostic fields in HES were explored, substantial agreement was observed for chronic ischaemia with tissue loss (Kappa = 0.63), but it was lower for chronic ischaemia without tissue loss (Kappa = 0.32) and acute limb ischaemia (Kappa = 0.15). Agreement on comorbidities was mixed; excellent for diabetes (Kappa = 0.82), moderate for chronic lung disease (Kappa = 0.56), chronic kidney disease (Kappa = 0.56), and ischaemic heart disease (Kappa = 0.45) and fair for chronic heart failure (Kappa = 0.35).

INTERPRETATION

The diagnostic ICD-10 codes currently used in HES cannot accurately differentiate between stages of PAD. Therefore, studies using HES to examine patterns of care and outcomes for patients with PAD are likely to suffer from misclassification bias. Adopting an extended ICD-10 system or the ICD-11 version released to the World Health Organisation member states in 2022, may overcome this problem.

FUNDING

Healthcare Quality Improvement Partnership (HQIP).

Frailty predicts poor longer-term outcomes in patients following lower limb open surgical revascularization

BACKGROUND

Frailty in vascular surgery patients is increasingly recognized as a marker of poor outcome. This provides particular challenges for patients with lower limb peripheral arterial disease who require surgical revascularization. This study aimed to assess the impact of frailty on short- and long-term outcome in this specific patient group using a specialty specific frailty score.

METHODS

Patients undergoing open surgical revascularization for chronic limb ischemia (January 2015-December 2016) were assessed. Demographics, mode of admission, diagnosis, and site of surgery were recorded alongside a variety of frailty-specific characteristics. We calculated the previously validated Addenbrookes Vascular Frailty Score (AVFS) and Long AVFS (LAVFS). Primary outcome was 3-year mortality.

RESULTS

Two hundred and sixty-one patients (75% men, median age 69 years) were studied. The median length of stay was 6 days with a 3-year mortality of 23%. The predictive power of vascular frailty scores showed that for 3-year mortality, area under the receiver operator curve values (AUROC) were specific for both the AVFS score (AUROC: 0.724, 95% CI: 0.654-0.794) and LAVFS Score (AUROC: 0.741, 95%CI: 0.670-0.813). Furthermore, the cumulative AVFS and LAVFS scores both predicted mortality over the follow-up period (P=0.0001) with increased mortality among patients with higher scores.

CONCLUSIONS

Incremental worsening of frailty, determined using a specialty specific frailty score, predicts mortality risk in patients undergoing lower limb surgical revascularization.

Antithrombotic Treatment Patterns of Patients with Symptomatic Peripheral Arterial Occlusive Disease in Germany: Evidence from Health Insurance Claims Data

Objectives: Patients with peripheral arterial occlusive disease (PAOD) are at risk of worsening limb symptoms, major adverse cardiovascular events and exhibit an impaired life expectancy. There is a lack of evidence on the extent of pharmacological secondary prevention in PAOD patients. This study assesses treatment patterns of antithrombotic agents in symptomatic PAOD patients. Methods: This is a retrospective cohort study using data from the second largest insurance fund in Germany, BARMER. We included symptomatic PAOD patients undergoing in-hospital treatment with an index admission between 1 January 2010 and 31 December 2017. Outcomes were proportions of single antiplatelets (SAPT), dual antiplatelets (DAPT), vitamin-K antagonists (VKA), or direct oral anticoagulants (DOAC) in the 12 months prior and 6 months after the index hospitalization. Non-parametric cumulative incidence for competing risks was estimated to account for censoring and death after discharge from hospital stay. Patient flows were visualised by alluvial diagrams. All analyses were stratified by intermittent claudication (IC) and chronic limb-threatening ischaemia (CLTI). The protocol was registered to ClinicalTrials.gov (NCT03909022). Results: A total of 80,426 unique patient encounters were identified. Mean age was 72.7 (46.3% female). Amongst all patients, 25.6% were on SAPT, 4.1% on DAPT, 9.1% on VKA, 3.9% on DOAC, 3.9% on both antiplatelets and oral anticoagulation, and 53.3% without any antithrombotic therapy during the 12 months before index stay. The estimated cumulative incidence was 37.9% SAPT, 14.8% DAPT, 7.5% VKA, 4.3% DOAC, 7.4% both, and 28.1% without any antithrombotic therapy during the 6 months after index stay. The considerable increases in antiplatelet therapy were mainly driven by the group of patients without antithrombotics before index stay. As compared with IC, patients who suffered from CLTI received less often antiplatelets but more often anticoagulants both before and after index stay. Conclusions: Utilisation rates of antithrombotic therapy increased considerably after in-hospital treatment for PAOD. Yet, remarkably high rates of symptomatic patients without any blood-thinning therapy constitute a major concern with respect to adequate secondary prevention of PAOD patients.

The Impact of Chronic Kidney Disease on Mid-Term Outcomes after Revascularisation of Peripheral Arterial Occlusive Disease: Results from a Prospective Cohort Study

OBJECTIVE

The current study aimed to determine the relationship between chronic kidney disease (CKD) and major 12-month outcomes for patients with in-hospital treatment for symptomatic peripheral arterial occlusive disease (PAOD).

METHODS

An analysis of the prospective longitudinal multicentric cohort study with 12-month follow-up was conducted including patients who underwent endovascular or open surgery for symptomatic PAOD at 35 German vascular centres (initial study protocol: NCT03098290). Severity of CKD was grouped into four stages combining information about the estimated glomerular filtration rate (eGFR) at baseline and dialysis dependency. Outcomes included overall mortality as well as the two composite endpoints of amputation or death, and of major cardiovascular events (MACE). 12-month incidences and adjusted hazard ratios were estimated using the Kaplan-Meier function and Cox proportional hazard models.

RESULTS

A total of 4354 patients (32% female, 69 years mean age, 68% intermittent claudication, 69% percutaneous endovascular revascularisation) were included and followed for 244 days in median. Thereof, 22% had any CKD and 5% had end stage kidney disease (ESKD) at baseline. The 12-month overall mortality rate was 3.6% (95% CI 2.3-4.9) with 96 events in the entire cohort: 147 were amputated or died (5.3%, 95% CI 5.2-5.3), and 277 had a MACE (9.5%, 95% CI 9.4-9.5). When compared with patients without kidney disease, ESKD was significantly associated with overall mortality (HR 1.9; 95% CI 1.1-3.5), amputation or death (HR 2.4; 95% CI 1.4-4.1), and MACE (HR 2.0; 95% CI 1.3-3.2).

CONCLUSIONS

In the current study on mid-term outcomes after invasive revascularisation for symptomatic PAOD, one out of five patients suffered from any CKD while those few with ESKD had twice the odds of death, of amputation or death, and of major adverse cardiovascular events after twelve months. These results emphasise that concomitant CKD and its impact on outcomes should be considered by severity while mild and moderate grades should not lead to ineffectual treatment strategies.

A cross-sectional survey study on the nutrition patterns of patients with peripheral artery disease

Background: Even though nutrition was demonstrated to have an impact on chronic atherosclerotic disease, there is a paucity of corresponding recommendations for patients with peripheral artery disease (PAD). A Mediterranean Diet based on daily intake of fruits and vegetables with high fibre, vegetable oil, and unsalted nuts including fish several times a week may have protective effects. This cross-sectional survey aimed to determine nutritional patterns amongst inpatients with PAD. Methods: All inpatients with symptomatic PAD who underwent revascularisation at a single centre between 1^st May 2018 and 31^st December 2021 were asked to fill out a questionnaire on nutritional intake. An 8-item frequency rating scale (from never to three times a day) was used for 15 food groups. For 11 of them, an adapted Mediterranean Diet score was calculated using the answers. The descriptive results were stratified by sex and disease stage (intermittent claudication vs. chronic limb-threatening ischaemia). Results: A total of 319 patients (31.7% female, 69.4 years in mean) were included. Thereof, 71.8% reported they did never receive any nutritional information considering their PAD disease. The mean adapted Mediterranean Diet score was 2.7 points (of maximum 11) with most patients not achieving the recommended servings per week for fruits (1.6%), vegetables (1.0%), and unsalted nuts (12.2%). The intake of cereals was sufficient (43.3%). When compared with men, women consumed more fruits and less meat. Conclusions: This survey demonstrated that although healthy nutrition may have a positive impact on patients with PAD, the education and adherence to a Mediterranean Diet was inappropriate. Nutritional patterns should be more focused in future PAD studies to derive specific recommendations and nutritional programmes as well as patient education in clinical practice.

Vorhersage von schweren Blutungsereignissen bei Patienten mit peripherer arterieller Verschlusskrankheit: Der OAC3-PAD-Risikoscore

Obwohl Patient:innen mit einer peripheren arteriellen Verschlusskrankheit (PAVK) aufgrund ihres Komorbiditäts- und Risikoprofils ein insgesamt erhöhtes Blutungsrisiko aufweisen, standen bisher keine validierten Werkzeuge zur Vorhersage des Blutungsrisikos zur Verfügung. Erschwerend kommt hinzu, dass viele randomisierte und kontrollierte Studien zu antithrombotischen Therapien Patient:innen mit erhöhtem Blutungsrisiko ausgeschlossen haben. Anhand von Routinedaten der Krankenkasse wurde mittels Verfahren des maschinellen Lernens ein pragmatisches Vorhersagemodell entwickelt und intern validiert. Mit dem OAC³-PAD-Risikoscore wurden acht Variablen identifiziert, die das Risiko von schweren Blutungsereignissen innerhalb eines Jahres nach stationärer Behandlung der PAVK vorhersagen können. Dieser Risikoscore kann dabei helfen, eine patientenzentrierte Risiko-Nutzen-Abwägung durchzuführen, um das maximale Potenzial aus den verfügbaren antithrombotischen Therapiestrategien zu schöpfen.

Medial Arterial Calcification: A Significant and Independent Contributor of Peripheral Artery Disease

Over 200 million individuals worldwide are estimated to have peripheral artery disease (PAD). Although the term peripheral can refer to any outer branch of the vasculature, the focus of this review is on lower-extremity arteries. The initial sequelae of PAD often include movement-induced cramping pain in the hips and legs or loss of hair and thinning of the skin on the lower limbs. PAD progresses, sometimes rapidly, to cause nonhealing ulcers and critical limb ischemia which adversely affects mobility and muscle tone; acute limb ischemia is a medical emergency. PAD causes great pain and a high risk of amputation and ultimately puts patients at significant risk for major adverse cardiovascular events. The negative impact on patients' quality of life, as well as the medical costs incurred, are huge. Atherosclerotic plaques are one cause of PAD; however, emerging clinical data now shows that nonatherosclerotic medial arterial calcification (MAC) is an equal and distinct contributor. This ATVB In Focus article will present the recent clinical findings on the prevalence and impact of MAC in PAD, discuss the known pathways that contribute specifically to MAC in the lower extremity, and highlight gaps in knowledge and tools that limit our understanding of MAC pathogenesis.

Distribution of Mobile Health Applications amongst Patients with Symptomatic Peripheral Arterial Disease in Germany: A Cross-Sectional Survey Study

Background: Broadly available digital and mobile health applications (also known as mHealth) have recently gained increasing attention by the vascular community, but very little is known about the dissemination and acceptance of such technologies in certain target populations. The current study aimed to determine the user behaviour and acceptance of such digital technologies amongst patients with peripheral arterial disease (PAD). Methods: A cross-sectional survey of consecutively treated inpatients at 12 university institutions, as well as one non-university institution, was conducted. All admitted patients with symptomatic PAD were surveyed for 30 consecutive days within a flexible timeframe between 1 July and 30 September 2021. The factors associated with smartphone use were estimated via backward selection within a logistic regression model with clustered standard errors. Results: A total of 326 patients participated (response rate 96.3%), thereof 102 (34.0%) were treated for intermittent claudication (IC, 29.2% women, 70 years in median) and 198 were treated for chronic limb-threatening ischaemia (CLTI, 29.5% women, 70 years in median). Amongst all of the patients, 46.6% stated that they had not changed their lifestyle and health behaviour since the index diagnosis (four years in median), and 33.1% responded that they were not aware of the reasons for all of their medication orders. Amongst all those surveyed, 66.8% owned a smartphone (IC: 70.6%, CLTI: 64.1%), thereof 27.9% needed regular user support. While 42.5% used smartphone apps, only 15.0% used mobile health applications, and 19.0% owned wearables. One out of five patients agreed that such technologies could help to improve their healthy lifestyle. Only higher age was inversely associated with smartphone possession. Conclusions: The current survey showed that smartphones are prevalent amongst patients with peripheral arterial disease, but only a small proportion used mobile health applications and a considerable number of patients needed regular user support. Almost half of the patients did not change their lifestyle and one third were not aware of the reasons for their medication orders, emphasising room for improvement. These findings can further help to guide future projects using such applications to identify those target populations that are reachable with digital interventions.

Update on the pathophysiology and medical treatment of peripheral artery disease

Approximately 6% of adults worldwide have atherosclerosis and thrombosis of the lower limb arteries (peripheral artery disease (PAD)) and the prevalence is rising. PAD causes leg pain, impaired health-related quality of life, immobility, tissue loss and a high risk of major adverse events, including myocardial infarction, stroke, revascularization, amputation and death. In this Review, I describe the pathophysiology, presentation, outcome, preclinical research and medical management of PAD. Established treatments for PAD include antithrombotic drugs, such as aspirin and clopidogrel, and medications to treat dyslipidaemia, hypertension and diabetes mellitus. Randomized controlled trials have demonstrated that these treatments reduce the risk of major adverse events. The drug cilostazol, exercise therapy and revascularization are the current treatment options for the limb symptoms of PAD, but each has limitations. Novel therapies to promote collateral and new capillary growth and treat PAD-related myopathy are under investigation. Methods to improve the implementation of evidence-based medical management, novel drug therapies and rehabilitation programmes for PAD-related pain, functional impairment and ischaemic foot disease are important areas for future research.

Initiation of SGLT2 Inhibitors and the Risk of Lower Extremity Minor and Major Amputation in Patients with Type 2 Diabetes and Peripheral Arterial Disease: A Health Claims Data Analysis

OBJECTIVE

To assess the association between long term risk of hospitalisation for heart failure (HHF) and lower extremity minor and major amputation (LEA) in patients initiating sodium glucose cotransporter 2 inhibitors (SGLT2i) suffering from type 2 diabetes and peripheral arterial disease (PAD). Outcomes were compared with patients without PAD and evaluated separately for the time periods before and after the official warning of the European Medicines Agency (EMA) in early 2017.

METHODS

This study used BARMER German health claims data including all patients suffering from type 2 diabetes initiating SGLT2i therapy between 1 January 2013 and 31 December 2019 with follow up until the end of 2020. New users of glucagon like peptide 1 receptor agonists (GLP1-RAs) were used as active comparators. Inverse probability weighting with truncated stabilised weights was used to adjust for confounding, and five year risks of HHF and LEA were estimated using Cox regression. Periods before and after the EMA warning were analysed separately and stratified by presence of concomitant PAD.

RESULTS

In total, 44 284 (13.6% PAD) and 56 878 (16.3% PAD) patients initiated SGLT2i or GLP1-RA, respectively. Before the EMA warning, initiation of SGLT2i was associated with a lower risk of HHF in patients with PAD (hazard ratio, HR, 0.85, 95% confidence interval, CI, 0.73 - 0.99) and a higher risk of LEA in patients without PAD (HR 1.79, 95% CI 1.04 - 2.92). After the EMA warning, the efficacy and safety endpoints were no longer statistically different between groups.

CONCLUSION

The results from this large nationwide real world study highlight that PAD patients exhibit generally high amputation risks. This study refutes the idea that the presence of PAD explains the excess LEA risk associated with initiation of SGLT2i. The fact that differentials among study groups diminished after the EMA warning in early 2017 emphasises that regulatory surveillance measures worked in everyday clinical practice.