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

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.

External validation of the OAC3-PAD risk score after endovascular revascularisation

Background: The OAC3-PAD bleeding risk score was developed to assess the bleeding risk in patients with peripheral arterial disease (PAD), however its performance in patients treated exclusively with endovascular revascularisation has not yet been tested. We aimed to externally validate the bleeding risk score for this patient cohort. Patients and methods: A retrospective observational study, analysing the data of all PAD patients successfully treated with endovascular revascularisation in a single centre within a five-year period. The performance of the Cox proportional hazards (CPH) model, upon which the OAC3-PAD bleeding risk score is based, was tested using calibration methods, discrimination, and a scaled Brier score for overall performance. The OAC3-PAD bleeding risk score was calculated for all patients, classifying them into the four respective risk groups. Kaplan-Meier curves were plotted for all risk groups and discrimination was tested using log-rank tests. Results: While discrimination of the CPH model was adequate, calibration of the model was poor and the scaled Brier score was 3.27% (95% CI 0.65%-4.40%). Of the 1,434 patients, 33 (2.3%) experienced a major bleeding event. The frequency of bleeding was 0.4% in the low risk group (3/736 patients), 0.8% in the low-to-moderate risk group (2/243 patients), 5.8% in the moderate-to-high risk group (15/258 patients), and 6.6% in the high risk group (13/197 patients). The OAC3-PAD score successfully discriminated each of the two lower bleeding risk groups from one of the two higher risk groups, but failed to discriminate among the two lower risk groups and the two higher risk groups, respectively. Conclusions: Although the OAC3-PAD score did not stratify patients into the four respective risk groups, it allowed discrimination between the low risk patients and the high risk patients. It could therefore become a useful tool for predicting major bleeding events in patients with PAD after endovascular revascularisation.

Antithrombotic Therapy in High Bleeding Risk, Part II: Noncardiac Percutaneous Interventions

Over the past decades, there have been great advancements in the antithrombotic management of patients undergoing percutaneous interventions, but most of the available evidence derives from studies conducted in the setting of cardiac interventions. Antithrombotic treatment regimens used in patients undergoing percutaneous cardiac interventions, in particular coronary, are frequently extrapolated to patients undergoing noncardiac interventions. However, the differences in risk profile of the population treated and the types of interventions performed may translate into differences is the safety and efficacy associated with antithrombotic therapy. Noncardiac percutaneous interventions are commonly performed in patients at high bleeding risk, which may indeed impact outcomes, hence underscoring the importance of risk stratification to guide clinical decision-making processes. In this review, we appraise the available evidence on antithrombotic therapy in high-bleeding-risk patients undergoing noncardiac percutaneous interventions.

A Nationwide Analysis in France on Sex Difference and Outcomes Following Carotid Intervention in Asymptomatic Patients

Objective: The impact of sex on outcomes following carotid endarterectomy (CEA) and carotid artery stenting (CAS) is not fully elucidated. The aim of this study was to analyze the association between sex and outcomes of asymptomatic patients who underwent primary carotid interventions in France. Methods: This nationwide retrospective study was performed using the French National Health Insurance Information System and included asymptomatic patients who underwent primary carotid intervention over a 10-year period (1 January 2013 to 31 August 2023). Symptomatic patients and patients who had peri-operative neurologic events were excluded. The primary endpoints were the occurrence of death and stroke/transient ischaemic attack (TIA) at 30 days, 1 and 5 years after patients' discharge. Results: In total, 115,879 patients were admitted for an index CEA (29.4% women) and 6500 for CAS (29.8% women). In the CEA group, no significant sex-related difference was observed for 30-day mortality; however, women had significantly lower 1-year and 5-year mortality rates compared to men (1.9% vs. 2.6%, p < 0.001 and 7.9% vs. 11.1%, p < 0.001). In the CAS group, women had lower 30-day, 1-year and 5-year mortality (0.6% vs. 1.0%, p = 0.040, 3.8% vs. 4.9%, p = 0.048, and 10.4% vs. 15.0%, p < 0.001). A multivariate analysis showed that sex was not associated with the risk of stroke/TIA and mortality at 30 days (OR 0.84 (95% CI 0.67-1.04) and 1.27 (95% CI 0.98-1.64)). Male sex was associated with a higher risk of 1-year and 5-year mortality (OR 1.24 (95% CI 1.13-1.36) and 1.25 (95% CI 1.18-1.31)), but a lower risk of stroke/TIA than female sex. Conclusions: No significant sex-related difference was observed at 30 days in patients being discharged alive and without peri-operative neurologic events. Male sex was associated with a higher risk of mortality but a lower risk of stroke/TIA at 1 and 5 years.

Dual Antithrombotic Therapy versus Anticoagulant Monotherapy for Major Adverse Limb Events in Patients with Concomitant Lower Extremity Arterial Disease and Atrial Fibrillation: A Propensity Score Weighted Analysis

OBJECTIVE

Patients with symptomatic lower extremity arterial disease (LEAD) are recommended to receive antiplatelet therapy, while direct oral anticoagulants (DOACs) are standard for stroke prevention in patients with atrial fibrillation (AF). For patients with concomitant LEAD and AF, data comparing dual antithrombotic therapy (an antiplatelet agent used in conjunction with a DOAC) vs. DOAC monotherapy are scarce. This retrospective cohort study, based on data from the Taiwan National Health Insurance Research Database, aimed to compare the efficacy and safety of these antithrombotic strategies.

METHODS

Patients with AF who underwent revascularisation for LEAD between 2012 - 2020 and received any DOAC within 30 days of discharge were included. Patients were grouped by antiplatelet agent exposure into the dual antithrombotic therapy and DOAC monotherapy groups. Inverse probability of treatment weighting was used to mitigate selection bias. Major adverse limb events (MALEs), ischaemic stroke or systemic embolism, and bleeding outcomes were compared. Patients were followed until the occurrence of any study outcome, death, or up to two years.

RESULTS

A total of 1 470 patients were identified, with 736 in the dual antithrombotic therapy group and 734 in the DOAC monotherapy group. Among them, 1 346 patients received endovascular therapy as the index revascularisation procedure and 124 underwent bypass surgery. At two years, dual antithrombotic therapy was associated with a higher risk of MALEs than DOAC monotherapy (subdistribution hazard ratio [SHR] 1.34, 95% confidence interval [CI] 1.15 - 1.56), primarily driven by increased repeat revascularisation. Dual antithrombotic therapy was also associated with a higher risk of major bleeding (SHR 1.43, 95% CI 1.05 - 1.94) and gastrointestinal bleeding (SHR 2.17, 95% CI 1.42 - 3.33) than DOAC monotherapy.

CONCLUSION

In patients with concomitant LEAD and AF who underwent peripheral revascularisation, DOAC monotherapy was associated with a lower risk of MALEs and bleeding events than dual antithrombotic therapy.

Patient Factors Influencing Prescription of Antithrombotic Medication After Lower Limb Endovascular Intervention

OBJECTIVE

There is significant practice variation in the use of antithrombotic therapy after endovascular intervention for lower limb peripheral arterial disease, with differences in medication choice and duration. Prescriber decision making is complex, and patient factors have been shown to substantially contribute to prescribing variation. To determine the influence of patient factors on antithrombotic prescribing, a discrete choice experiment was distributed to vascular surgeons and trainees across Australia and Aotearoa New Zealand.

METHODS

After pilot testing, the discrete choice experiment questionnaire was distributed to 300 vascular surgeons and trainee members of the Australian and New Zealand Society for Vascular Surgery. Multinomial logistic regression models were used to analyse patient factors that had the most influence on decisions to prescribe a second antithrombotic agent, and the preferred choice of antithrombotic (clopidogrel 75 mg daily or rivaroxaban 2.5 mg twice daily) in addition to aspirin 100 mg daily. The odds ratio (OR) with 95% confidence interval (CI) reported preference strength.

RESULTS

A total of 44 questionnaires were completed between September and October 2023, reaching the 15% targeted response rate. Prescribing a second antithrombotic was more likely after femoropopliteal stenting compared with angioplasty (OR 1.89, 95% CI 1.20 - 2.13), and in chronic limb threatening ischaemia compared with intermittent claudication (OR 1.58, 95% CI 1.20 - 2.13). Most respondents preferred clopidogrel over rivaroxaban (62%), with over a third of respondents exclusively prescribing clopidogrel. Patients with stents (OR 1.77, 95% CI 1.32 - 2.37) or moderate bleeding risk (OR 1.38, 95% CI 0.97 - 1.84) were more likely to receive clopidogrel than rivaroxaban.

CONCLUSION

This study demonstrates that vascular surgeons primarily prioritise antithrombotic prescribing decisions by procedure type. Clopidogrel is more likely to be prescribed than rivaroxaban as a second agent in combination with aspirin, especially after stenting. Knowing these clinician preferences can target implementation strategies towards supporting decision making in subgroups of patients according to individual risk profiles.

Editor's Choice - Revascularisation for Peripheral Artery Disease in France: Implications for the Implementation of VOYAGER-PAD

OBJECTIVE

The VOYAGER-PAD trial demonstrated the interest in dual pathway inhibition (DPI) (low dose rivaroxaban plus aspirin) to reduce limb and cardiovascular events after revascularisation for peripheral artery disease (PAD), but its applicability in clinical practice has not yet been assessed. This study aimed to assess the number of patients revascularised in France for PAD and to estimate the proportion of those matching the VOYAGER-PAD trial selection criteria. A secondary objective was to examine the prognosis of revascularised patients in a real world setting.

METHODS

This observational retrospective study was conducted on the national hospital discharge database and included all patients with PAD who underwent lower extremity revascularisation for PAD (without lower extremity revascularisation in the two years prior to inclusion) from 1 January 2016 to 31 December 2019. Available VOYAGER-PAD selection criteria were then applied to the study population.

RESULTS

In total, 180 870 patients were included (mean age 72.0 ± 12.2 years, 30.9% female), with approximately 45 000 patients revascularised annually. Among them, 90 379 (50.0%) matched the VOYAGER-PAD trial criteria (VOYAGER-PAD eligible subgroup; mean age 69.8 ± 12.1 years, 29.5% female). In the study population and the VOYAGER-PAD eligible subgroup, 33.9% and 26.6% of patients had diabetes, 28.1% and 19.9% had chronic coronary artery disease, and 14.6% and 5.7% had renal failure, respectively. Overall, 73.1% of study patients were treated by an endovascular approach (75.5% in the VOYAGER-PAD eligible subgroup). In patients with more than one year of follow up, 45.4% of study patients and 36.0% of the VOYAGER-PAD eligible subgroup experienced a limb or cardiovascular event. The median time until the first event and in hospital death was 4.8 months and 7.8 months, respectively (6.7 months and 12.9 months in the VOYAGER-PAD eligible subgroup).

CONCLUSION

The burden of PAD for revascularisation and secondary events is considerable. One half of revascularised patients in France are eligible for DPI therapy. Those patients are younger, with fewer comorbidities, and better outcomes.

External Validation of the OAC3-PAD Bleeding Score in a Nationwide Population of Patients Undergoing Invasive Treatment for Peripheral Arterial Disease

OBJECTIVE

The OAC3-PAD score was developed to predict bleeding risk in patients with lower extremity peripheral arterial disease (PAD), but its performance in concomitant international cohorts is largely unknown. This study aimed to validate the OAC3-PAD score in an unselected nationwide population of patients undergoing invasive treatment for symptomatic PAD.

METHODS

This was a nationwide cohort study including all patients who underwent a first revascularisation procedure or major amputation for symptomatic PAD in Denmark from 2000 - 2021. The study population was stratified based on OAC3-PAD score, and the one year risk of major bleeding was assessed, accounting for the competing risk of death. The score performance was evaluated using calibration plots, C statistic, Brier score, and the index of prediction accuracy (IPA).

RESULTS

A total of 52 016 patients were included (mean age 71 years, 43.8% female). The one year risk of major bleeding increased with higher OAC3-PAD score, ranging from 1.6% (95% confidence interval [CI] 1.4 - 1.8%) to 2.3% (95% CI 2.0 - 2.5%), 3.5% (95% CI 3.2 - 3.8%), and 5.2% (95% CI 4.8 - 5.6%) for patients with low, low moderate, moderate high, and high score, respectively. Using patients with low risk as reference, the OAC3-PAD score effectively categorised patients, demonstrating statistically significant differences in bleeding risk across strata. However, the score showed modest discriminative performance, with a C statistic of 65% (95% CI 63 - 66%) and a Brier score of 2.6% (95% CI 2.5 - 2.7%). Nevertheless, it performed significantly better than the null model, as indicated by an IPA of 3.1%.

CONCLUSION

Among patients who underwent invasive treatment for symptomatic PAD in routine care, the OAC3-PAD score was associated with greater risk of major bleeding with increasing score level. However, its discriminatory ability was modest, and the clinical utility remains to be determined.