Long-term use of dual antiplatelet therapy for the secondary prevention of atherothrombotic events: Meta-analysis of randomized controlled trials

Agreement Between Mega-Trials and Smaller Trials: A Systematic Review and Meta-Research Analysis

Importance

Mega-trials can provide large-scale evidence on important questions.

Objective

To explore how the results of mega-trials compare with the meta-analysis results of trials with smaller sample sizes.

Data Sources

ClinicalTrials.gov was searched for mega-trials until January 2023. PubMed was searched until June 2023 for meta-analyses incorporating the results of the eligible mega-trials.

Study Selection

Mega-trials were eligible if they were noncluster nonvaccine randomized clinical trials, had a sample size over 10 000, and had a peer-reviewed meta-analysis publication presenting results for the primary outcome of the mega-trials and/or all-cause mortality.

Data Extraction and Synthesis

For each selected meta-analysis, we extracted results of smaller trials and mega-trials included in the summary effect estimate and combined them separately using random effects. These estimates were used to calculate the ratio of odds ratios (ROR) between mega-trials and smaller trials in each meta-analysis. Next, the RORs were combined using random effects. Risk of bias was extracted for each trial included in our analyses (or when not available, assessed only for mega-trials). Data analysis was conducted from January to June 2024.

Main Outcomes and Measures

The main outcomes were the summary ROR for the primary outcome and all-cause mortality between mega-trials and smaller trials. Sensitivity analyses were performed with respect to the year of publication, masking, weight, type of intervention, and specialty.

Results

Of 120 mega-trials identified, 41 showed a significant result for the primary outcome and 22 showed a significant result for all-cause mortality. In 35 comparisons of primary outcomes (including 85 point estimates from 69 unique mega-trials and 272 point estimates from smaller trials) and 26 comparisons of all-cause mortality (including 70 point estimates from 65 unique mega-trials and 267 point estimates from smaller trials), no difference existed between the outcomes of the mega-trials and smaller trials for primary outcome (ROR, 1.00; 95% CI, 0.97-1.04) nor for all-cause mortality (ROR, 1.00; 95% CI, 0.97-1.04). For the primary outcomes, smaller trials published before the mega-trials had more favorable results than the mega-trials (ROR, 1.05; 95% CI, 1.01-1.10) and subsequent smaller trials published after the mega-trials (ROR, 1.10; 95% CI, 1.04-1.18).

Conclusions and Relevance

In this meta-research analysis, meta-analyses of smaller studies showed overall comparable results with mega-trials, but smaller trials published before the mega-trials gave more favorable results than mega-trials. These findings suggest that mega-trials need to be performed more often given the relative low number of mega-trials found, their low significant rates, and the fact that smaller trials published prior to mega-trial report more beneficial results than mega-trials and subsequent smaller trials.

Unravelling the progress and potential of drug-eluting stents and drug-coated balloons in cardiological insurgencies

AIM

Coronary artery disease (CAD) is the leading cause of mortality. Though percutaneous transluminal angioplasty followed by stenting is still the default treatment of choice for revascularization of obstructive CAD, the high rate of restenosis compromises the outcomes of endovascular procedures. To overcome restenosis, drug-eluting stents (DES) and drug-coated balloons (DCB) are designed that release antiproliferative drugs like sirolimus, paclitaxel, everolimus, etc., over time to inhibit cell growth and proliferation. Our review aims to summarize the challenges and progress of DES/DCBs in clinical settings.

MATERIAL AND METHODS

The comprehensive review, search and selection encompasses in relevant articles through Google Scholar, Springer online, Cochrane library and PubMed that includes research articles, reviews, letters and communications, various viewpoints, meta-analyses, randomized trials and quasi-randomized trials. Several preclinical and clinical data have been included from National Institutes of Health and clinicaltrials.gov websites.

KEY FINDINGS

Challenges like delayed endothelialization, stent thrombosis (ST), and inflammation was prominent in first-generation DES. Second-generation DES with improved designs and drug coatings enhanced biocompatibility with fewer complications. Gradual absorption of bioresorbable DES over time mitigated long-term issues associated with permanent implants. Polymer-free DES addressed the inflammation concerns but still, they leave behind metallic stents in the vasculature. As an alternative therapeutic strategy, DCB were developed to minimize inflammation in the vessel. Although both DES and DCBs have shown considerable progress, challenges persist.

SIGNIFICANCE

This review illustrates the advancements in the designs, preparation technologies, biodegradable materials, and drugs used as well as challenges associated with DES and DCBs in clinical settings.

Medical Management of Peripheral Artery Disease

Peripheral artery disease (PAD) is a common type of atherosclerotic disease of the lower extremities associated with reduced quality of life and ambulatory capacity. Major adverse cardiovascular events and limb amputations are the leading cause of morbidity and mortality in this population. Optimal medical therapy is therefore critical in these patients to prevent adverse events. Risk factor modifications, including blood pressure control and smoking cessation, in addition to antithrombotic agents, peripheral vasodilators, and supervised exercise therapy are key pillars of medical therapy. Revascularization procedures represent key touch points between patients and health care providers and serve as opportunities to optimize medical therapy and improve long-term patency rates and outcomes. This review summarizes the aspects of medical therapy that all providers should be familiar with when caring for patients with PAD in the peri-revascularization period.

Long-Term Outcomes of Local Tirofiban Infusion for Intracranial Atherosclerosis-Related Occlusion

Local tirofiban infusion has been reported as a rescue strategy for intracranial atherosclerotic stenosis (ICAS)-related stroke. However, the long-term outcomes of local tirofiban infusion during endovascular reperfusion therapy (ERT) for ICAS-related stroke are still uncertain. This study aimed to investigate the long-term outcomes of local tirofiban infusion during ERT. We retrospectively analyzed acute patients with ICAS-related stroke who were treated with local tirofiban as a rescue strategy during ERT. The primary outcomes were ischemic stroke, transient ischemic stroke (TIA), and stroke-related death within 30 days. Secondary outcomes included ischemic stroke and TIA beyond 30 days and up to 2 years after ERT in the corresponding treated vessel, symptomatic brain hemorrhage, any stroke, and non-stroke-related death. During a median follow-up of 24.0 months, 12 patients developed an ischemic stroke and TIA (4 within 30 days and 8 afterward). The 1-year risk of stroke and TIA was 9.2% (95% confidence interval, 8.0–18.6%). This study demonstrates that 1-year outcomes of local tirofiban infusion were comparable to the results of intracranial stenting in patients with symptomatic ICAS. Local tirofiban infusion for ICAS-related stroke may be a feasible rescue strategy that can have a bridging role until the maximum effect of antiplatelet agents is achieved.

P2Y12 Inhibitor Monotherapy is Associated with Superior Outcomes as Compared to Aspirin Monotherapy in Chronic Limb Threatening Ischemia

OBJECTIVE

Antiplatelet therapy is recommended in patients with Peripheral Arterial Disease (PAD) to reduce cardiovascular risk and improve outcomes. However, issues including the drug of choice and use of dual antiplatelet (DAPT) vs monotherapy remain unclear. This study aims to compare the impact of aspirin (ASA) monotherapy, P2Y12 monotherapy and DAPT on limb salvage (LS), amputation-free survival (AFS) and overall survival (OS) in patients undergoing lower extremity peripheral endovascular intervention (PVI) for chronic limb threatening ischemia (CLTI).

METHODS

The Vascular Quality Initiative PVI registry was used to identify index procedures completed for CLTI between 3/1/2010- 09/30/2017. Patients were categorized by antiplatelet use at the time of last follow-up. Patients not on antiplatelet therapy were compared with ASA, P2Y12 monotherapy and DAPT. Propensity score matched (PSM) samples were created for direct ASA vs P2Y12 and P2Y12 vs DAPT comparisons; veracity was confirmed by Chi-Square and Hosmer-Lemeshow. Kaplan Meier and Cox regression were performed for OS, AFS and LS.

RESULTS

12,433 index PVI were completed for CLTI in 11,503 subjects in the pre-matched sample. Antiplatelet use at follow-up was: 12% none, 31% ASA, 14% P2Y12 and 43% DAPT. Median FU was 1389 days. P2Y12 monotherapy was associated with improved outcomes as compared to ASA monotherapy, OS (87.8% vs 85.5%, P=.026; Cox HR 0.82(0.68-0.98); P= .03), AFS (79.6% vs74.8%, P<.001; Cox HR 0.75(0.65-0.86); P < .001) and LS (89.5% vs 86.8%, P= .013; Cox HR 0 .74(0.60-0.91); P= .004). P2Y12 monotherapy and DAPT had comparable OS (87.8% vs 88.9%, P= .62; Cox HR 0.94(0.77-1.14); P= .50), AFS (79.6% vs 81.5%, P= .33; Cox HR 0.92(0.78-1.07); P= .28) and LS (91.7% vs 89.4, P=.03; Cox HR 0.80 (0.64-1.00); P= .06).

CONCLUSIONS

P2Y12 monotherapy was associated with superior overall survival (OS), amputation-free survival (AFS) and limb salvage (LS) as compared to ASA monotherapy, and comparable OS, LS and AFS to dual antiplatelet therapy (DAPT) in patients undergoing peripheral endovascular interventions for chronic limb threatening ischemia. P2Y12 monotherapy may be considered over ASA monotherapy and DAPT in CLTI patient, especially in patients at high bleeding risk.

Challenges of long-term dual antiplatelet therapy use following acute coronary syndromes

An acute coronary syndrome (ACS) event is associated with a high risk of recurrent ACS, stroke, and death. To ameliorate the risk of subsequent events, current guidelines for ST-segment elevation myocardial infarction and non-ST-segment elevation ACS recommend long-term management strategies for secondary prevention including risk factor modification and anti-ischemic and antiplatelet therapies. Dual antiplatelet therapy (DAPT), comprising aspirin plus a P2Y₁₂ inhibitor, is a critical component of secondary prevention therapy following ACS. However, despite the importance of DAPT for secondary prevention after ACS, questions remain over the optimal duration of therapy. Clinical evidence is emerging that maintenance DAPT >12 months lowers the risk of recurrent ACS events; however, this benefit must be considered against any potential risks of prolonged DAPT such as bleeding. Several tools for bleeding risk assessment have shown promise; however, their limited accuracy and discriminative power necessitates further development. Assessment of patient ischemic risk should consider the complexity of the percutaneous coronary intervention (PCI) procedure, anatomic burden of coronary artery disease, and additional underlying risk factors. Consequently, identifying patients in whom the risk:benefit ratio favors prolonged DAPT may prove invaluable for clinicians in deciding which patients should continue or stop taking DAPT at 12 months after PCI, or consider P2Y₁₂ inhibitor monotherapy as an option. This article reviews the most recent information about the risks and benefits of DAPT continued for >12 months after ACS and provides critical guidance to assist physicians in identifying patients most likely to benefit from a secondary prevention strategy with DAPT.

Extended dual antiplatelet therapy with ticagrelor 60 mg in patients with prior myocardial infarction: The design of ALETHEIA, a multi-country observational study

Introduction

Clinical guidelines recommend extended treatment with dual antiplatelet therapy (DAPT) with ticagrelor 60 mg (twice daily) beyond 12 months in high‐risk patients with a history of myocardial infarction (MI) who have previously tolerated DAPT and are not at heightened bleeding risk. However, evidence on patterns of use and associated clinical outcomes in routine clinical practice is limited.

Methods

ALETHEIA is an observational, multi‐country study, designed to describe characteristics, treatment persistence, and bleeding and cardiovascular (CV) outcomes in post‐MI patients who initiate ticagrelor 60 mg in routine clinical practice (NCT04568083). The study will include electronic health data in the United States (US; Medicare, commercial claims) and Europe (Sweden, Italy, United Kingdom, Germany). Characteristics will be described among patients with and without ticagrelor 60 mg ≥1 year post‐MI. Assuming an a priori threshold of 5000 person‐years on‐treatment is met, to ensure sufficient precision, clinical outcomes (bleeding and CV events) among patients treated with ticagrelor 60 mg will be assessed. Risk factors for clinical outcomes and treatment discontinuation will be assessed in patients with ticagrelor 60 mg and meta‐analysis used to combine estimates across databases. Cohort selection will initiate from the ticagrelor 60 mg US and European approval dates and end February 2020. An estimated total of 7250 patients prescribed ticagrelor 60 mg are expected to be included.

Discussion

An increased understanding of patterns of ticagrelor 60 mg use and associated clinical outcomes among high‐risk patients with a prior MI is needed. The a priori specified stepwise approach adapted in this observational study is expected to generate useful evidence for clinical decision‐making and treatment optimization.

Evidence-Based Medical Management of Peripheral Artery Disease

Peripheral artery disease is an atherosclerotic disease of the lower extremities associated with high cardiovascular mortality. Management of this condition may include lifestyle modifications, medical management, endovascular repair, or surgery. The medical approach to peripheral artery disease is multifaceted and includes cholesterol reduction, antiplatelet therapy, anticoagulation, peripheral vasodilators, blood pressure management, exercise therapy, and smoking cessation. Adherence to this regimen can reduce limb-related complications like critical limb ischemia and amputation, as well as systemic complications of atherosclerosis like stroke and myocardial infarction. Relative to coronary artery disease, peripheral artery disease is an undertreated condition. In this article, we explore the evidence behind medical therapies for the management of peripheral artery disease.

Umbrella review and meta-analysis of antiplatelet therapy for peripheral artery disease

Background

The literature on antiplatelet therapy for peripheral artery disease has historically been summarized inconsistently, leading to conflict between international guidelines. An umbrella review and meta-analysis was performed to summarize the literature, allow assessment of competing safety risks and clinical benefits, and identify weak areas for future research.

Methods

MEDLINE, Embase, DARE, PROSPERO and Cochrane databases were searched from inception until January 2019. All meta-analyses of antiplatelet therapy in peripheral artery disease were included. Quality was assessed using AMSTAR scores, and GRADE analysis was used to quantify the strength of evidence. Data were pooled using random-effects models.

Results

Twenty-eight meta-analyses were included. Thirty-three clinical outcomes and 41 antiplatelet comparisons in 72 181 patients were analysed. High-quality evidence showed that antiplatelet monotherapy reduced non-fatal strokes (3 (95 per cent c.i. 0 to 6) fewer per 1000 patients), In symptomatic patients, it reduced cardiovascular deaths (8 (0 to 16) fewer per 1000 patients), but increased the risk of major bleeding (7 (3 to 14) more events per 1000). In asymptomatic patients, monotherapy reduced non-fatal strokes (5 (0 to 8) fewer per 1000), but had no other clinical benefit. Dual antiplatelet therapy caused more major bleeding after intervention than monotherapy (37 (8 to 102) more events per 1000), with very low-quality evidence of improved endovascular patency (risk ratio 4·00, 95 per cent c.i. 0·91 to 17·68).

Conclusion

Antiplatelet monotherapy has minimal clinical benefit for asymptomatic peripheral artery disease, and limited benefit for symptomatic disease, with a clear risk of major bleeding. There is a lack of evidence to guide antiplatelet prescribing after peripheral endovascular intervention.

Global Vascular Guidelines on the Management of Chronic Limb-Threatening Ischemia

GUIDELINE SUMMARY

Chronic limb-threatening ischemia (CLTI) is associated with mortality, amputation, and impaired quality of life. These Global Vascular Guidelines (GVG) are focused on definition, evaluation, and management of CLTI with the goals of improving evidence-based care and highlighting critical research needs. The term CLTI is preferred over critical limb ischemia, as the latter implies threshold values of impaired perfusion rather than a continuum. CLTI is a clinical syndrome defined by the presence of peripheral artery disease (PAD) in combination with rest pain, gangrene, or a lower limb ulceration >2 weeks duration. Venous, traumatic, embolic, and nonatherosclerotic etiologies are excluded. All patients with suspected CLTI should be referred urgently to a vascular specialist. Accurately staging the severity of limb threat is fundamental, and the Society for Vascular Surgery Threatened Limb Classification system, based on grading of Wounds, Ischemia, and foot Infection (WIfI) is endorsed. Objective hemodynamic testing, including toe pressures as the preferred measure, is required to assess CLTI. Evidence-based revascularization (EBR) hinges on three independent axes: Patient risk, Limb severity, and ANatomic complexity (PLAN). Average-risk and high-risk patients are defined by estimated procedural and 2-year all-cause mortality. The GVG proposes a new Global Anatomic Staging System (GLASS), which involves defining a preferred target artery path (TAP) and then estimating limb-based patency (LBP), resulting in three stages of complexity for intervention. The optimal revascularization strategy is also influenced by the availability of autogenous vein for open bypass surgery. Recommendations for EBR are based on best available data, pending level 1 evidence from ongoing trials. Vein bypass may be preferred for average-risk patients with advanced limb threat and high complexity disease, while those with less complex anatomy, intermediate severity limb threat, or high patient risk may be favored for endovascular intervention. All patients with CLTI should be afforded best medical therapy including the use of antithrombotic, lipid-lowering, antihypertensive, and glycemic control agents, as well as counseling on smoking cessation, diet, exercise, and preventive foot care. Following EBR, long-term limb surveillance is advised. The effectiveness of nonrevascularization therapies (eg, spinal stimulation, pneumatic compression, prostanoids, and hyperbaric oxygen) has not been established. Regenerative medicine approaches (eg, cell, gene therapies) for CLTI should be restricted to rigorously conducted randomizsed clinical trials. The GVG promotes standardization of study designs and end points for clinical trials in CLTI. The importance of multidisciplinary teams and centers of excellence for amputation prevention is stressed as a key health system initiative.

New perspectives on treatment strategies for patient with acute myeloid leukemia and complex karyotype abnormalities after percutaneous coronary intervention: A case report

RATIONALE

Acute myeloid leukemia (AML), in patients with coronary heart disease (CHD) and treated percutaneous coronary intervention (PCI), is rarely seen in clinic. There are few similar cases reported, and there are no evidence-based medicine guidelines for the treatment.

PATIENT CONCERNS

A 52-year-old man was diagnosed with coronary atherosclerotic heart disease in November 2011, and received a stent placement in the left anterior descending coronary artery 1 year later. One day after the surgery, his laboratory tests showed pancytopenia.

DIAGNOSES

Based on precise diagnosis of leukemia, namely cell morphology, immunology, cytogenetics, and molecular biological typing, the patient was diagnosed with AML-M2.

INTERVENTIONS

The patient received idarubicin with cytarabine in 1st cycles, and single cytarabine regimen was used in 2nd and 3rd cycles for the accumulative toxicity of idarubicin in postinduction chemotherapy. Meanwhile, staged-treatment strategy was implemented by using antiplatelet drugs during different chemotherapy phases, and personalized pharmaceutical care on the basis of the recognition of potential adverse effects of chemotherapy regimen.

OUTCOMES

Until now, the disease-free survival in the patient has been over 6 years, and he is still followed up in clinic.

LESSONS

Although leukemia accompanied with coronary heart disease, even after receiving the coronary stenting therapy is rarely seen in clinic, the treatment with antiplatelet drugs for post chemotherapy patients with coronary disease is necessary. Clinical pharmacists are supposed to be more proficient in developing personalized drug treatment strategies, especially maintaining the balance between the effect and the risk in difficult and complex cases.

Global vascular guidelines on the management of chronic limb-threatening ischemia

Chronic limb-threatening ischemia (CLTI) is associated with mortality, amputation, and impaired quality of life. These Global Vascular Guidelines (GVG) are focused on definition, evaluation, and management of CLTI with the goals of improving evidence-based care and highlighting critical research needs. The term CLTI is preferred over critical limb ischemia, as the latter implies threshold values of impaired perfusion rather than a continuum. CLTI is a clinical syndrome defined by the presence of peripheral artery disease (PAD) in combination with rest pain, gangrene, or a lower limb ulceration >2 weeks duration. Venous, traumatic, embolic, and nonatherosclerotic etiologies are excluded. All patients with suspected CLTI should be referred urgently to a vascular specialist. Accurately staging the severity of limb threat is fundamental, and the Society for Vascular Surgery Threatened Limb Classification system, based on grading of Wounds, Ischemia, and foot Infection (WIfI) is endorsed. Objective hemodynamic testing, including toe pressures as the preferred measure, is required to assess CLTI. Evidence-based revascularization (EBR) hinges on three independent axes: Patient risk, Limb severity, and ANatomic complexity (PLAN). Average-risk and high-risk patients are defined by estimated procedural and 2-year all-cause mortality. The GVG proposes a new Global Anatomic Staging System (GLASS), which involves defining a preferred target artery path (TAP) and then estimating limb-based patency (LBP), resulting in three stages of complexity for intervention. The optimal revascularization strategy is also influenced by the availability of autogenous vein for open bypass surgery. Recommendations for EBR are based on best available data, pending level 1 evidence from ongoing trials. Vein bypass may be preferred for average-risk patients with advanced limb threat and high complexity disease, while those with less complex anatomy, intermediate severity limb threat, or high patient risk may be favored for endovascular intervention. All patients with CLTI should be afforded best medical therapy including the use of antithrombotic, lipid-lowering, antihypertensive, and glycemic control agents, as well as counseling on smoking cessation, diet, exercise, and preventive foot care. Following EBR, long-term limb surveillance is advised. The effectiveness of nonrevascularization therapies (eg, spinal stimulation, pneumatic compression, prostanoids, and hyperbaric oxygen) has not been established. Regenerative medicine approaches (eg, cell, gene therapies) for CLTI should be restricted to rigorously conducted randomizsed clinical trials. The GVG promotes standardization of study designs and end points for clinical trials in CLTI. The importance of multidisciplinary teams and centers of excellence for amputation prevention is stressed as a key health system initiative.

Medication adherence, biological and lifestyle risk factors in patients with myocardial infarction: a ten-year follow-up on socially differentiated cardiac rehabilitation

Objective: There is strong evidence that medication adherence and lifestyle changes are essential in patients undergoing secondary cardiovascular disease prevention. Cardiac rehabilitation (CR) increases medication adherence and improves lifestyle changes. Patients with cardiac diseases and a low educational level and patients with little social support are less responsive to improve medication adherence and to adapt lifestyle changes. The aim of the present study was to investigate the long-term effects of a socially differentiated CR intervention on medication adherence as well as changes in biological and lifestyle risk factors at two- five- and ten-year follow-up. Design: A prospective cohort study. Setting: The cardiac ward at Aarhus University Hospital, Denmark. Intervention: A socially differentiated CR intervention in addition to the standard CR program. Subjects: Patients admitted with first-episode myocardial infarction between 2000 and 2004, N = 379. Patients were defined as socially vulnerable or non-socially vulnerable according to their educational level and extent of social network. Main outcome measures: Primary outcome was medication adherence to antithrombotics, beta-blockers, statins and angiotensin-converting enzyme inhibitors. Secondary outcomes were biological and lifestyle risk factors defined as; total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, glycated hemoglobin, blood pressure and smoking status. Results: No significant long-term effect of the intervention was found. Conclusions: The results indicate a non-significant effect of the intervention. However, it was found that equality in health was improved in the study population except concerning smoking. General practitioners manage to support the long-term secondary cardiovascular disease prevention in all patients regardless of social status. Key points The socially differentiated intervention did not significantly improve medication adherence or biological and lifestyle risk factors. Despite the non-significant effect of the intervention, equality in health was improved except concerning smoking. General practitioners managed to support the long-term secondary cardiovascular disease prevention in all patients regardless of social status.

Bleeding risk assessment for stroke patients on antithrombotic therapy

INTRODUCTION

After an ischemic cerebrovascular event the risk of new ischemic events is high, therefore antithrombotic therapy are indicated to prevent stroke recurrence.

DISCUSSION

Despite its clear benefit, these therapies increase the risk of bleeding. Therefore, it is essential to identify high hemorrhagic risk patients. There are different predictive models of hemorrhage, in particular of intracranial hemorrhage, associated with the use of antiaggregants in patients who have presented an ischemic stroke or TIA, such as the CCSC, intracranial scales -B2LEED3S score or S2TOP-BLEED. However, though main international guidelines recommend the use of scales, in particular, the HAS-BLED score, to assess the risk of bleeding in anticoagulated patients, there is no specific recommendation in the case of the use of antiplatelet drugs.

CONCLUSIONS

In this review we present the main models currently available for the prediction of bleeding of antithrombotic therapy in patients who have had a stroke or TIA.

Comparative Review of Oral P2Y12 Inhibitors

Current practice guidelines recommend dual antiplatelet therapy comprised of aspirin and a purinergic signaling receptor Y₁₂ (P2Y₁₂) for patients following acute coronary syndrome. This article compares the efficacy, safety, and other characteristics of the three available oral P2Y₁₂ inhibitors-clopidogrel, prasugrel, and ticagrelor.

Antithrombotic treatment in peripheral artery disease

Abstract. This review treats antithrombotic use for peripheral arterial disease (PAD). In asymptomatic patients, there are no scientific data to support single antiplatelet therapy (SAPT) for primary prophylaxis. In symptomatic PAD, SAPT with aspirin or clopidogrel is indicated. The efficacy of aspirin is controversial. Clopidogrel may be preferred over aspirin. Ticagrelor is not superior to clopidogrel in reducing major adverse cardiovascular events and major adverse limb events, but lowers the risk of ischaemic stroke. In symptomatic PAD, dual antiplatelet therapy (DAPT) with clopidogrel and aspirin does not provide benefit over SAPT with aspirin alone and is associated with increased risk of major bleeding. DAPT with ticagrelor 60 mg b. i. d. and aspirin provides a significant major adverse cardiovascular events reduction in symptomatic PAD patients and may be considered in PAD patients with prior myocardial infarction. The use of a new thrombin receptor antagonist, vorapaxar, on top of SAPT or DAPT with aspirin and/or clopidogrel, reduces the risk of acute limb ischaemia and peripheral artery revascularization in patients with symptomatic PAD, at the cost of an increased risk for bleeding. Rivaroxaban (2.5 mg b. i. d.) plus aspirin (100 mg daily) is the first antithrombotic association that proved significant benefit for PAD patients, in terms of strong endpoints – total mortality and cardiovascular mortality. Therefore, this association shows the strongest evidence for secondary prevention of symptomatic PAD patients. In PAD patients undergoing percutaneous peripheral interventions, at least four weeks of DAPT with aspirin and clopidogrel is recommended after infrainguinal stent implantation. Stenting below-the-knee arteries is often followed by a longer period of DAPT, but no specific evidence is available. Anticoagulation is mandatory to prevent arterial occlusion during radial or brachial invasive procedures. The strategy includes use of unfractioned heparin, bivalirudin or enoxaparin. Vitamin K antagonists may be considered after autologous vein infrainguinal bypass.

Intra-Arterial Drug and Light Delivery for Photodynamic Therapy Using Visudyne®: Implication for Atherosclerotic Plaque Treatment

Photodynamic therapy (PDT), which is based on the activation of photosensitizers with light, can be used to reduce plaque burden. We hypothesized that intra-arterial photosensitizer administration and photo-activation will lead to high and rapid accumulation within the plaque with reduced systemic adverse effects. Thus, this "intra-arterial" PDT would be expected to have less side effects and due to the short time involved would be compatible with percutaneous coronary interventions.

AIM

We characterized the dose-dependent uptake and efficacy of intra-arterial PDT using Liposomal Verteporfin (Visudyne®), efficient for cancer-PDT but not tested before for PDT of atherosclerosis.

METHODS AND RESULTS

Visudyne® (100, 200, and 500 ng/ml) was perfused for 5-30 min in atherosclerotic aorta isolated from ApoE(-/-) mice. The fluorescence Intensity (FI) after 15 min of Visudyne® perfusion increased with doses of 100 (FI-5.5 ± 1.8), 200 (FI-31.9 ± 1.9) or 500 ng/ml (FI-42.9 ± 1.2). Visudyne® (500 ng/ml) uptake also increased with the administration time from 5 min (FI-9.8 ± 2.5) to 10 min (FI-23.3 ± 3.0) and 15 min (FI-42.9 ± 3.4) before reaching saturation at 30 min (FI-39.3 ± 2.4) contact. Intra-arterial PDT (Fluence: 100 and 200 J/cm(2), irradiance-334 mW/cm(2)) was applied immediately after Visudyne® perfusion (500 ng/ml for 15 min) using a cylindrical light diffuser coupled to a diode laser (690 nm). PDT led to an increase of ROS (Dihydroethidium; FI-6.9 ± 1.8, 25.3 ± 5.5, 43.4 ± 13.9) and apoptotic cells (TUNEL; 2.5 ± 1.6, 41.3 ± 15.3, 58.9 ± 6%), mainly plaque macrophages (immunostaining; 0.3 ± 0.2, 37.6 ± 6.4, 45.3 ± 5.4%) respectively without laser irradiation, or at 100 and 200 J/cm(2). Limited apoptosis was observed in the medial wall (0.5 ± 0.2, 8.5 ± 4.7, 15.3 ± 12.7%). Finally, Visudyne®-PDT was found to be associated with reduced vessel functionality (Myogram).

CONCLUSION

We demonstrated that sufficient accumulation of Visudyne® within plaque could be achieved in short-time and therefore validated the feasibility of local intravascular administration of photosensitizer. Intra-arterial Visudyne®-PDT preferentially affected plaque macrophages and may therefore alter the dynamic progression of plaque development.