Perceptions of Canadian Vascular Surgeons Toward Pharmacologic Risk Reduction in Patients with Peripheral Artery Disease: 2018 Update

Evidence for clinician underprescription of and patient non-adherence to guideline-recommended cardiovascular medications among adults with peripheral artery disease: protocol for a systematic review and meta-analysis

INTRODUCTION

International guidelines recommend that adults with peripheral artery disease (PAD) be prescribed antiplatelet, statin and antihypertensive medications. However, it is unclear how often people with PAD are underprescribed these drugs, which characteristics predict clinician underprescription of and patient non-adherence to guideline-recommended cardiovascular medications, and whether underprescription and non-adherence are associated with adverse health and health system outcomes.

METHODS AND ANALYSIS

We will search MEDLINE, EMBASE and Evidence-Based Medicine Reviews from 2006 onwards. Two investigators will independently review abstracts and full-text studies. We will include studies that enrolled adults and reported the incidence and/or prevalence of clinician underprescription of or patient non-adherence to guideline-recommended cardiovascular medications among people with PAD; adjusted risk factors for underprescription of/non-adherence to these medications; and adjusted associations between underprescription/non-adherence to these medications and outcomes. Outcomes will include mortality, major adverse cardiac and limb events (including revascularisation procedures and amputations), other reported morbidities, healthcare resource use and costs. Two investigators will independently extract data and evaluate study risk of bias. We will calculate summary estimates of the incidence and prevalence of clinician underprescription/patient non-adherence across studies. We will also conduct subgroup meta-analyses and meta-regression to determine if estimates vary by country, characteristics of the patients and treating clinicians, population-based versus non-population-based design, and study risks of bias. Finally, we will calculate pooled adjusted risk factors for underprescription/non-adherence and adjusted associations between underprescription/non-adherence and outcomes. We will use Grading of Recommendations, Assessment, Development and Evaluation to determine estimate certainty.

ETHICS AND DISSEMINATION

Ethics approval is not required as we are studying published data. This systematic review will synthesise existing evidence regarding clinician underprescription of and patient non-adherence to guideline-recommended cardiovascular medications in adults with PAD. Results will be used to identify evidence-care gaps and inform where interventions may be required to improve clinician prescribing and patient adherence to prescribed medications.

PROSPERO REGISTRATION NUMBER

CRD42022362801.

Machine Learning to Predict Outcomes of Endovascular Intervention for Patients With PAD

Importance

Endovascular intervention for peripheral artery disease (PAD) carries nonnegligible perioperative risks; however, outcome prediction tools are limited.

Objective

To develop machine learning (ML) algorithms that can predict outcomes following endovascular intervention for PAD.

Design, Setting, and Participants

This prognostic study included patients who underwent endovascular intervention for PAD between January 1, 2004, and July 5, 2023, with 1 year of follow-up. Data were obtained from the Vascular Quality Initiative (VQI), a multicenter registry containing data from vascular surgeons and interventionalists at more than 1000 academic and community hospitals. From an initial cohort of 262 242 patients, 26 565 were excluded due to treatment for acute limb ischemia (n = 14 642) or aneurysmal disease (n = 3456), unreported symptom status (n = 4401) or procedure type (n = 2319), or concurrent bypass (n = 1747). Data were split into training (70%) and test (30%) sets.

Exposures

A total of 112 predictive features (75 preoperative [demographic and clinical], 24 intraoperative [procedural], and 13 postoperative [in-hospital course and complications]) from the index hospitalization were identified.

Main Outcomes and Measures

Using 10-fold cross-validation, 6 ML models were trained using preoperative features to predict 1-year major adverse limb event (MALE; composite of thrombectomy or thrombolysis, surgical reintervention, or major amputation) or death. The primary model evaluation metric was area under the receiver operating characteristic curve (AUROC). After selecting the best performing algorithm, additional models were built using intraoperative and postoperative data.

Results

Overall, 235 677 patients who underwent endovascular intervention for PAD were included (mean [SD] age, 68.4 [11.1] years; 94 979 [40.3%] female) and 71 683 (30.4%) developed 1-year MALE or death. The best preoperative prediction model was extreme gradient boosting (XGBoost), achieving the following performance metrics: AUROC, 0.94 (95% CI, 0.93-0.95); accuracy, 0.86 (95% CI, 0.85-0.87); sensitivity, 0.87; specificity, 0.85; positive predictive value, 0.85; and negative predictive value, 0.87. In comparison, logistic regression had an AUROC of 0.67 (95% CI, 0.65-0.69). The XGBoost model maintained excellent performance at the intraoperative and postoperative stages, with AUROCs of 0.94 (95% CI, 0.93-0.95) and 0.98 (95% CI, 0.97-0.99), respectively.

Conclusions and Relevance

In this prognostic study, ML models were developed that accurately predicted outcomes following endovascular intervention for PAD, which performed better than logistic regression. These algorithms have potential for important utility in guiding perioperative risk-mitigation strategies to prevent adverse outcomes following endovascular intervention for PAD.

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.

Impact of guideline-directed medical therapy on 5-year mortality in patients with newly diagnosed peripheral artery disease

OBJECTIVE

Current guidelines recommend that patients with peripheral artery disease (PAD) should be treated with antithrombotic agents, renin-angiotensin-system blockers, and statins. However, the clinical impact of guideline-directed medical therapy (GDMT) on long-term mortality in patients with newly diagnosed PAD remains unclear. We aimed to investigate the prevalence of GDMT and evaluate 5-year mortality according to GDMT after PAD diagnosis.

METHODS

This retrospective cohort study, using nationwide health insurance claims data in Korea, included patients newly diagnosed with PAD between 2006 and 2015. GDMT was defined as the use of all drugs, including antithrombotic agents, renin-angiotensin-system blockers, and statins, within 3 months of PAD diagnosis. The primary endpoint was all-cause mortality.

RESULTS

We investigated 19,561 newly diagnosed patients with PAD without proven cardiovascular disease. Among the study population, 4378 patients (22.4%) were categorized in the GDMT and 15,183 (77.6%) in the non-GDMT groups. During the 5-year follow-up, GDMT showed a lower incidence of all-cause mortality than that of non-GDMT (2.8% vs 4.8%; adjusted hazard ratio, 0.329; 95% confidence interval, 0.257-0.421; P < .001). Even in the propensity-matched population, GDMT showed a lower mortality rate than non-GDMT (hazard ratio, 0.283; 95% confidence interval, 0.217-0.370; P < .001). As the number of guideline-recommended drugs increased, the mortality rate decreased proportionately.

CONCLUSIONS

After PAD diagnosis, GDMT was associated with a lower incidence of mortality regardless of proven cardiovascular disease. This retrospective analysis showed an insufficient prevalence of GDMT among patients with PAD in real-world practice.

Increasing Awareness for Peripheral Artery Disease through the Identification of Novel Biomarkers

Peripheral artery disease (PAD) is a chronic atherosclerotic disorder that involves the lower extremity arteries, manifesting in claudication, rest pain, and tissue loss [...].

Perceptions of Canadian vascular surgeons toward artificial intelligence and machine learning

Background

Artificial intelligence (AI) and machine learning (ML) are rapidly advancing fields with increasing utility in health care. We conducted a survey to determine the perceptions of Canadian vascular surgeons toward AI/ML.

Methods

An online questionnaire was distributed to 162 members of the Canadian Society for Vascular Surgery. Self-reported knowledge, attitudes, and perceptions with respect to potential applications, limitations, and facilitators of AI/ML were assessed.

Results

Overall, 50 of the 162 Canadian vascular surgeons (31%) responded to the survey. Most respondents were aged 30 to 59 years (72%), male (80%), and White (67%) and practiced in academic settings (72%). One half of the participants reported that their knowledge of AI/ML was poor or very poor. Most were excited or very excited about AI/ML (66%) and were interested or very interested in learning more about the field (83.7%). The respondents believed that AI/ML would be useful or very useful for diagnosis (62%), prognosis (72%), patient selection (56%), image analysis (64%), intraoperative guidance (52%), research (88%), and education (80%). The limitations that the participants were most concerned about were errors leading to patient harm (42%), bias based on patient demographics (42%), and lack of clinician knowledge and skills in AI/ML (40%). Most were not concerned or were mildly concerned about job replacement (86%). The factors that were most important to encouraging clinicians to use AI/ML models were improvements in efficiency (88%), accurate predictions (84%), and ease of use (84%). The comments from respondents focused on the pressing need for the implementation of AI/ML in vascular surgery owing to the potential to improve care delivery.

Conclusions

Canadian vascular surgeons have positive views on AI/ML and believe this technology can be applied to multiple aspects of the specialty to improve patient care, research, and education. Current self-reported knowledge is poor, although interest was expressed in learning more about the field. The facilitators and barriers to the effective use of AI/ML identified in the present study can guide future development of these tools in vascular surgery.

Urinary Cystatin C Has Prognostic Value in Peripheral Artery Disease

Despite its association with adverse outcomes, peripheral artery disease (PAD) remains undertreated. Cystatin C is elevated in patients with renal disease and may be a marker of cardiovascular disease. We examined the prognostic ability of urinary Cystatin C (uCystatinC) in predicting adverse PAD-related events. In this prospective case-control study, urine samples were collected from patients with PAD (n = 121) and without PAD (n = 77). The cohort was followed for 2 years. uCystatinC was normalized to urinary creatinine (uCr) (uCystatinC/uCr; μg/g). The primary outcome was major adverse limb event (MALE; composite of vascular intervention (open or endovascular) or major limb amputation). The secondary outcome was worsening PAD status (drop in ABI ≥ 0.15). Multivariable Cox regression and Kaplan–Meier analyses were performed to assess the prognostic value of uCystatinC/uCr with regards to predicting MALE and worsening PAD status. Our analysis demonstrated that patients with PAD had significantly higher median [IQR] uCystatinC/uCr levels (24.9 μg/g [14.2–32.9] vs. 20.9 μg/g [11.1–27.8], p = 0.018). Worsening PAD status and MALE were observed in 39 (20%) and 34 (17%) patients, respectively. uCystatinC/uCr predicted worsening PAD status with a hazard ratio (HR) of 1.78 (95% CI 1.12–2.83, p = 0.015), which persisted after controlling for baseline demographic and clinical characteristics (adjusted HR 1.79 [95% CI 1.11–2.87], p = 0.017). Patients with high uCystatinC/uCr had a lower 2-year freedom from MALE (77% vs. 89%, p = 0.025) and worsening PAD status (63% vs. 87%, p = 0.001). Based on these data, higher uCystatinC/uCr levels are associated with adverse PAD-related events and have prognostic value in risk-stratifying individuals for further diagnostic vascular evaluation or aggressive medical management.

Social Deprivation and Peripheral Artery Disease

The link between peripheral artery disease and socioeconomic status is complex. The objective of this narrative review is to explore this relationship in detail, including how social factors impact the development, management, and outcomes of peripheral artery disease. Although the current literature on this topic is limited, some patterns do emerge. Populations of low socioeconomic status appear to be at increased risk for the development of peripheral artery disease, due to factors such as increased prevalence of cardiovascular risk factors (i.e. cigarette smoking) and decreased access to care. However, variables that are more difficult to quantify, such as chronic stress and health literacy, also likely play a significant role. Among those who are living with peripheral artery disease, socioeconomic status can also affect disease management. Secondary prevention strategies, such as medication use, smoking cessation, and exercise therapy, are underutilized in socially deprived populations. This underutilization of evidence-based management leads to adverse outcomes in these groups, including increased rates of amputation and decreased post-operative survival. The recognition of the importance of social factors in prognosis is an important first step towards addressing this health disparity. Moving forward, interventions that help to identify those who are at high risk and help to improve access to care in populations of low socioeconomic status, will be critical to improving outcomes.

Rates of intervention for claudication versus chronic limb-threatening ischemia in Canada and United States

BACKGROUND

Previous studies have demonstrated important geographic variations in peripheral artery disease (PAD) management despite existing guidelines. We assessed differences in patient characteristics, procedural technique, and outcomes for PAD interventions in Canada vs. United States.

METHODS

The Vascular Quality Initiative (VQI) was used to identify all patients who underwent endovascular intervention or surgical bypass for PAD between 2010-2019 in Canada and United States. Independent t-test and chi-square test were performed to assess differences between countries in terms of demographic, clinical, and procedural characteristics. The primary outcome was the percentage of interventions performed for claudication vs. chronic limb-threatening ischemia (CLTI). Perioperative outcomes were in-hospital mortality and index limb amputation. The long-term outcome was 1-year amputation-free survival. Univariate/multivariate logistic regression and Cox proportional hazards analysis were performed to investigate associations between region and outcomes.

RESULTS

246,770 US patients and 3,467 Canadian patients underwent revascularization for PAD during the study period. There was a higher proportion of endovascular interventions in the US (75.9% vs. 69.2%, OR 1.41 [95% CI 1.31 - 1.51], p < 0.001). American patients were younger with more comorbidities, including hypertension, diabetes, and coronary artery disease. The percentage of interventions performed for claudication was significantly higher in the US (42.3% vs. 35.7%, OR 1.31 [95% CI 1.22 - 1.44], p < 0.001). This persisted after controlling for demographic, clinical, and procedural characteristics (adjusted OR 1.05 [95% CI 1.01 - 1.10], p = 0.02). Perioperative outcomes were similar between countries after adjustment for baseline differences: in-hospital mortality (adjusted OR 1.07 [95% CI 0.69 - 1.62], p = 0.75) and index limb amputation (adjusted OR 0.67 [95% CI 0.43 - 1.07], p = 0.09). However, 1-year amputation-free survival was higher in the US (84.1% vs. 71.0%, HR 1.61 [95% CI 1.47 - 1.76], p < 0.001). Multivariable Cox proportional hazards analysis demonstrated that the factor most strongly associated with index limb amputation or death at 1-year was intervention for CLTI (HR 1.56 [95% CI 1.54 - 1.58], p < 0.001).

CONCLUSIONS

There are significant variations in PAD management between US and Canada. In particular, a higher proportion of interventions are performed for claudication rather than CLTI in the US compared to Canada. This is an important contributor to the higher 1-year amputation-free survival rate in US patients. Reasons for these differences should be assessed by future studies and evidence-based care may be standardized by targeted quality improvement projects.

Evidence-based medical treatment of peripheral arterial disease: A rapid review

ABSTRACT Introduction: Peripheral arterial disease (PAD) treatment guidelines recommend the use of statins and antiplatelets in all PAD patients to reduce adverse cardiovascular and limb-related outcomes. In addition, hypertension and diabetes should be treated to reach recommended targets. The aim of this rapid review was to evaluate the level of adherence to evidence-based medical therapy (EBMT) recommended by PAD treatment guidelines in the real-world setting. Methods: We searched PubMed and Embase using keywords, MeSH and Emtree terms related to the population, exposure and outcomes from their inception to 22 September 2020. We included randomised controlled trials, non-randomised studies, and observational studies reporting adherence to at least 1 of these 4 drug classes: (1) statins, (2) antiplatelets, (3) antihypertensives and (4) antidiabetic drugs. Non-English articles, abstracts, dissertations, animal studies and case reports or series were excluded. A narrative summary of the results was performed. Results: A total of 42 articles were included in the review. The adherence to lipid-lowering drugs/statins ranged from 23.5 to 92.0% and antiplatelets from 27.5 to 96.3%. Only 7 and 5 studies reported use of “any anti-hypertensive” and “any anti-diabetic” medications, respectively, and the proportion of the cohort treated were generally close to the proportion with hypertension and/or diabetes. Adherence in studies published in 2016–2020 ranged from 52.4–89.6% for lipid-lowering drugs and 66.2–96.3% for antiplatelets. Conclusion: EBMT adherence in PAD patients was highly variable and a substantial proportion in many settings were undertreated. There was also a notable lack of studies in Asian populations. Keywords: Evidence-practice gap, medication adherence, pharmacoepidemiology

Evidence-Based Recommendations for Medical Management of Peripheral Artery Disease

Patients with lower limb artery stenosis or occlusion (peripheral artery disease; PAD) have been determined to be at very high risk of both major adverse cardiovascular events, such as myocardial infarction and stroke, and major adverse limb events, such as amputation and requirement for artery surgery.

Effective medical management has been identified as key in reducing this risk; however, this is often poorly implemented in clinical practice. Thus, the aim of this narrative review was to summarize the current evidence on the medical management of PAD in order to inform clinicians and highlight recommendations for clinical practice. International guidelines, randomized controlled trials, and relevant systematic reviews and meta-analyses have been included in this study. The focus was the management of the key modifiable risk factors to mitigate possible adverse events through prescription of anti-platelet and anticoagulation drugs and medications to control low-density lipoprotein cholesterol, blood pressure, and diabetes and aid smoking cessation. The available evidence from randomized clinical trials provide a strong rationale for the need for holistic medical management programs that are effective in achieving uptake of these medical therapies in patients with PAD. In conclusion, people with PAD have some of the highest adverse event rates among those with cardiovascular diseases. Secondary preventive measures have been proven effective in reducing these adverse events; however, they remain to be adequately implemented. Thus, the need for an effective implementation program has emerged to reduce adverse events in this patient group.

Pilot screening program for lower extremities atherosclerotic disease in a population of central Greece

BACKGROUND

Screening program in lower extremity atherosclerotic disease (LEAD) has not been widely implemented from health systems. The aim of this study was to assess the incidence of LEAD in Greece though a pilot LEAD screening program.

METHODS

Males >60 years old without known diagnosis of LEAD or chronic renal disease were invited through public primary health care institutions to participate in a pilot screening program in Central Greece. Demographics, atherosclerotic risk factors and other comorbidities were recorded. LEAD was defined as ankle-brachial pressure index (ABPI) of <0.9 or >1.4.

RESULTS

Among a total of 1152 individuals (invitation acceptance 70%; 1152/1638) LEAD was detected in 13% (148); including 7% with ABPI<0.9 and 6% with ABPI>1.4. Comparing the groups with ABPI<0.9 vs. normal ABPI, abnormal ABPI was associated with older age (P=0.001), hypertension (HT) (P=0.037), smoking (P=0.002), duration of smoking (P=0.01), packs/year (P=0.002), coronary artery disease (P=0.02), chronic obstructive pulmonary disease (P=0.028) and cerebrovascular disease (P=0.001). After multivariate analysis, increased age (0.94, CI: 0.026-5.2; P=0.022), history of HT (2.4, CI: 0.44- 3.7; P=0.05) and longer duration of smoking (0.9, CI: 0.01-6.1; 0.013) were associated with ABPI <0.9. Abnormally higher ABPI (>1.4) was not associated with any factor. Among those without known CAD or CVD (96/148), 37.5% (36/96) were on statins and 21% (20/96) on antiplatelets.

CONCLUSIONS

Incidence of LEAD was 13% in a male >60 years-old population of central Greece; these individuals maybe undertreated. ABPI<0.9 was diagnosed in 7% and was associated with older age, HT and duration of smoking.

Variations in the Management of Claudication in a Tertiary Care Center

BACKGROUND

Multiple societal guidelines recommend medical optimization and exercise therapy for patients with claudication prior to lower extremity revascularization (LER). However, the application of those guidelines in practice remains unknown. Our hypothesis is that vascular surgeons (VS) are more adherent to guidelines compared to non-VS treating claudication.

METHODS

The records of patients undergoing LER for claudication in a single center were reviewed, and adherence to guidelines prior to LER was assessed. Patients received conservative therapy if the impact of claudication on quality of life was documented, ankle-brachial index (ABI) was obtained, and patients were treated with at least 3 months of walking exercise and smoking cessation when indicated.

RESULTS

There were 187 patients treated for claudication (VS = 65, non-VS = 122). There were 161 patients who underwent endovascular intervention, 19 patients had an open revascularization, and 7 patients had a hybrid procedure. Patients treated by VS were younger and more likely to be African American. Patients treated by non-VS were more likely to have hyperlipidemia, coronary artery disease, smoke, and be on antiplatelet and statin medications. VS was more likely to assess pattern of symptoms with claudication and obtain ABIs compared to non-VS, although the mean ABIs were no different. VS was more likely to use walking exercises and smoking cessation when indicated before LER. Even though 70.8% and 31.1% of patients treated by VS and non-VS respectively were recommended walking exercises, only 33.8% and 18.0% were given a period of 3 months to benefit from it prior to LER. Conservative therapy was significantly higher among VS compared to non-VS but was overall low (VS = 12.3%, non-VS = 3.3%, P = 0.016). After a mean follow-up of 3.1 ± 1.3 years, there was no difference in mortality or major amputation.

CONCLUSIONS

Although adherence to guidelines in the medical management of vascular claudication prior to LER was higher among VS compared with non-VS, overall rates of adherence were low. Stricter institutional protocols and oversight across specialties are needed to reinforce the application of the established standards of care.

Orientin suppresses oxidized low-density lipoproteins induced inflammation and oxidative stress of macrophages in atherosclerosis

Atherosclerosis is a main reason for peripheral vascular disease. The present study aims to investigate the effects of macrophage foam cells which is an initial part in atherosclerosis. RAW 264.7 were treated with 80 μg/mL oxidized low-density lipoproteins (ox-LDL) to mimic atherosclerosis in vitro. Orientin, a flavonoid from plants, inhibited ox-LDL induced TNFα, IL-6, IL-1β expression increase. In addition, Orientin also can inhibit the emergence of ox-LDL-induced lipid droplets. The scavenger receptor CD 36 of ox-LDL was significantly downregulated after the treatment of orientin. Inhibition of ROS generation and increasing of eNOS expression by Orientin treatment was used to show the alteration of oxidative stress. Moreover, the expression levels of Angiopoietin-like 2 (angptl2) and NF-κB were significantly upregulated after cells induced by ox-LDL, whereas orientin significantly reversed the effects of ox-LDL. Orientin inhibited ox-LDL-induced inflammation and oxidative stress, and CD36 may be the key regulator during Orientin action.