A pooled analysis of the durability and predictors of treatment response of cilostazol in patients with intermittent claudication

Effect of cilostazol on healing of achilles tendon ruptures: an experimental study on rats

PURPOSE

This study aimed to evaluate whether cilostazol (phosphodiesterase III inhibitor) could enhance the healing of Achilles tendon ruptures in rats.

MATERIALS AND METHODS

The Achilles tendons of 24 healthy male adult rats were incised and repaired. The rats were randomly allocated to cilostazol and control groups. The cilostazol group received daily intragastric administration of 50 mg/kg cilostazol for 28 days, while the control group did not receive any medication. The rats were sacrificed on the 30th day, and the Achilles tendon was evaluated for biomechanical properties, histopathological characteristics, and immunohistochemical analysis.

RESULTS

All rats completed the experiment. The Movin sum score of the control group was significantly higher (p = 0.008) than that of the cilostazol group, with means of 11 ± 0.63 and 7.50 ± 1.15, respectively. Similarly, the mean Bonar score was significantly higher (p = 0.026) in the control group compared to the cilostazol group (8.33 ± 1.50 vs. 5.5 ± 0.54, respectively). Moreover, the Type I/Type III Collagen ratio was notably higher (p = 0.016) in the cilostazol group (52.2 ± 8.4) than in the control group (34.6 ± 10.2). The load to failure was substantially higher in the cilostazol group than in the control group (p = 0.034), suggesting that the tendons in the cilostazol group were stronger and exhibited greater resistance to failure.

CONCLUSIONS

The results of this study suggest that cilostazol treatment significantly improves the biomechanical and histopathological parameters of the healing Achilles tendon in rats. Cilostazol might be a valuable supplementary therapy in treating Achilles tendon ruptures in humans. Additional clinical studies are, however, required to verify these outcomes.

Cilostazol for peripheral arterial disease - a position paper from the Italian Society for Angiology and Vascular Medicine

Cilostazol is a quinolinone-derivative selective phosphodiesterase inhibitor and is a platelet-aggregation inhibitor and arterial vasodilator for the symptomatic treatment of intermittent claudication (IC). Cilostazol has been shown to improve walking distance for patients with moderate to severe disabling intermittent claudication who do not respond to exercise therapy and who are not candidates for vascular surgical or endovascular procedures. Several studies evaluated the pharmacological effects of cilostazol for restenosis prevention and indicated a possible effect on re-endothelialization mediated by hepatocyte growth factor and endothelial precursor cells, as well as inhibiting smooth muscle cell proliferation and leukocyte adhesion to endothelium, thereby exerting an anti-inflammatory effect. These effects may suggest a potential effectiveness of cilostazol in preventing restenosis and promoting the long-term outcome of revascularization interventions. This review aimed to point out the role of cilostazol in treating patients with peripheral arterial disease, particularly with IC, and to explore its possible role in restenosis after lower limb revascularization.

The Pink Tax: Sex and Gender Disparities in Peripheral Artery Disease

Peripheral artery disease (PAD) is an atherosclerotic disease associated with significant functional impairment, morbidity, and mortality. Among women, PAD remains poorly recognized and undermanaged. Compared with men, women with PAD tend to be underdiagnosed or misdiagnosed, have poorer quality of life, and experience higher rates of PAD-related morbidity and cardiovascular mortality. In this review, we describe the sex- and gender-related differences in the epidemiology, presentation, diagnosis, and management of PAD. We provide specific recommendations to overcome these factors, including greater awareness and an increased emphasis on tailored and more aggressive interventions for women with PAD. Such changes are warranted and necessary to achieve more equitable outcomes in women with PAD, including improved limb outcomes, enhanced lifestyle, and cardiovascular risk reduction.

Sex, Endothelial Cell Functions, and Peripheral Artery Disease

Peripheral artery disease (PAD) is caused by blocked arteries due to atherosclerosis and/or thrombosis which reduce blood flow to the lower limbs. It results in major morbidity, including ischemic limb, claudication, and amputation, with patients also suffering a heightened risk of heart attack, stroke, and death. Recent studies suggest women have a higher prevalence of PAD than men, and with worse outcomes after intervention. In addition to a potential unconscious bias faced by women with PAD in the health system, with underdiagnosis, and lower rates of guideline-based therapy, fundamental biological differences between men and women may be important. In this review, we highlight sexual dimorphisms in endothelial cell functions and how they may impact PAD pathophysiology in women. Understanding sex-specific mechanisms in PAD is essential for the development of new therapies and personalized care for patients with PAD.

Sex and Racial Disparities in Peripheral Artery Disease

Several studies have shown that women and racial and ethnic minority patients are at increased risk of developing lower extremity peripheral artery disease and suffering adverse outcomes from it, but a knowledge gap remains regarding the underlying causes of these increased risks. Both groups are more likely to be underdiagnosed, have poorly managed contributory comorbidities, and incur disparities in treatment and management postdiagnosis. Opportunities for improvement in the care of women and racial and ethnic minorities with peripheral artery disease include increased rates of screening, higher rates of clinical suspicion (particularly in the absence of typical symptoms of intermittent claudication), and more aggressive risk factor management before and after the diagnosis of peripheral artery disease.

Dual Antiplatelet Therapy: A Concise Review for Clinicians

Dual antiplatelet therapy (DAPT) combines two antiplatelet agents to decrease the risk of thrombotic complications associated with atherosclerotic cardiovascular diseases. Emerging data about the duration of DAPT is being published continuously. New approaches are trying to balance the time, benefits, and risks for patients taking DAPT for established cardiovascular diseases. Short-term dual DAPT of 3-6 months, or even 1 month in high-bleeding risk patients, is equivalent in terms of efficacy and effectiveness compared to long-term DAPT for patients who experienced percutaneous coronary intervention in an acute coronary syndrome setting. Prolonged DAPT beyond 12 months reduces stent thrombosis, major adverse cardiovascular events, and myocardial infarction rates but increases bleeding risk. Extended DAPT does not significantly benefit stable coronary artery disease patients in reducing stroke, myocardial infarction, or cardiovascular death. Ticagrelor and aspirin reduce cardiovascular events in stable coronary artery disease with diabetes but carry a higher bleeding risk. Antiplatelet therapy duration in atrial fibrillation patients after percutaneous coronary intervention depends on individual characteristics and bleeding risk. Antiplatelet therapy is crucial for post-coronary artery bypass graft and transcatheter aortic valve implantation; Aspirin (ASA) monotherapy is preferred. Antiplatelet therapy duration in peripheral artery disease depends on the scenario. Adding vorapaxar and cilostazol may benefit secondary prevention and claudication, respectively. Carotid artery disease patients with transient ischemic attack or stroke benefit from antiplatelet therapy and combining ASA and clopidogrel is more effective than ASA alone. The optimal duration of DAPT after carotid artery stenting is uncertain. Resistance to ASA and clopidogrel poses an incremental risk of deleterious cardiovascular events and stroke. The selection and duration of antiplatelet therapy in patients with cardiovascular disease requires careful consideration of both efficacy and safety outcomes. The use of combination therapies may provide added benefits but should be weighed against the risk of bleeding. Further research and clinical trials are needed to optimize antiplatelet treatment in different patient populations and clinical scenarios.

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.

Endothelial cell dysfunction: Implications for the pathogenesis of peripheral artery disease

Peripheral artery disease (PAD) is caused by occluded or narrowed arteries that reduce blood flow to the lower limbs. The treatment focuses on lifestyle changes, management of modifiable risk factors and vascular surgery. In this review we focus on how Endothelial Cell (EC) dysfunction contributes to PAD pathophysiology and describe the largely untapped potential of correcting endothelial dysfunction. Moreover, we describe current treatments and clinical trials which improve EC dysfunction and offer insights into where future research efforts could be made. Endothelial dysfunction could represent a target for PAD therapy.

Sex Differences in Peripheral Artery Disease

Peripheral artery disease (PAD) is a prevalent condition that confers substantial morbidity and mortality and remains underdiagnosed as well as undertreated in the overall population. Although PAD prevalence is similar or higher in women compared with men, associations of traditional and nontraditional risk factors with PAD and clinical manifestations of PAD differ by sex and may contribute to delayed or lack of diagnosis in women. Such sex-based differences in the manifestation of PAD may arise from sexual dimorphism in the vascular substrate in health as well as sex variation in the responses to vascular stressors. Despite the availability of proven therapies for improving symptoms and reducing risk of ischemic cardiovascular and limb events among patients with diagnosed PAD, important sex differences in treatment and outcomes have been observed. We provide an overview of current knowledge regarding sex differences in the epidemiology, pathophysiology, clinical presentation, and management of PAD.

Medical Management of Peripheral Artery Disease

Peripheral artery disease is a highly morbid yet undertreated atherosclerotic disease. The cornerstones of peripheral artery disease therapy consist of smoking cessation, lipid-lowering therapy, and hypertension treatment. More recently, clinical trials have demonstrated that novel antiplatelet and antithrombotic therapies reduce the risk of both cardiovascular and limb events in this patient population. In this review, we highlight the components of optimal medical therapy of peripheral artery disease and the evidence base for these therapies.

Contemporary Medical Management of Peripheral Artery Disease

Peripheral artery disease (PAD) is a manifestation of systemic atherosclerosis. Modifiable risk factors including cigarette smoking, dyslipidemia, diabetes, poor diet quality, obesity, and physical inactivity, along with underlying genetic factors contribute to lower extremity atherosclerosis. Patients with PAD often have coexistent coronary or cerebrovascular disease, and increased likelihood of major adverse cardiovascular events, including myocardial infarction, stroke and cardiovascular death. Patients with PAD often have reduced walking capacity and are at risk of acute and chronic critical limb ischemia leading to major adverse limb events, such as peripheral revascularization or amputation. The presence of polyvascular disease identifies the highest risk patient group for major adverse cardiovascular events, and patients with prior critical limb ischemia, prior lower extremity revascularization, or amputation have a heightened risk of major adverse limb events. Medical therapies have demonstrated efficacy in reducing the risk of major adverse cardiovascular events and major adverse limb events, and improving function in patients with PAD by modulating key disease determining pathways including inflammation, vascular dysfunction, and metabolic disturbances. Treatment with guideline-recommended therapies, including smoking cessation, lipid lowering drugs, optimal glucose control, and antithrombotic medications lowers the incidence of major adverse cardiovascular events and major adverse limb events. Exercise training and cilostazol improve walking capacity. The heterogeneity of risk profile in patients with PAD supports a personalized approach, with consideration of treatment intensification in those at high risk of adverse events. This review highlights the medical therapies currently available to improve outcomes in patients with PAD.

Application of stem cell-derived exosomes in ischemic diseases: opportunity and limitations

Ischemic diseases characterized by an insufficient blood flow that leads to a decrease in oxygen and nutrient uptake by cells have emerged as an important contributor to both disability and death worldwide. Up-regulation of angiogenesis may be a key factor for the improvement of ischemic diseases. This article searched articles in PubMed with the following keywords: stem cells, exosomes, angiogenesis, ischemic diseases either alone or in grouping form. The most relevant selected items were stem cell-derived exosomes and ischemic diseases. A growing body of evidence indicates that stem cells produce exosomes, which is the novel emerging approach to cell-to-cell communication and offers a new standpoint on known therapeutic strategies of ischemic diseases. Exosomes transport biological molecules such as many types of proteins, RNAs, DNA fragments, signaling molecules, and lipids between cells. Different stem cells release exosomes representing beneficial effects on ischemic diseases as they promote angiogenesis both in vitro and in vivo experiments. Application of exosomes for therapeutic angiogenesis opened new opportunities in the regenerative medicine, however, some limitations regarding exosomes isolation and application remain concerned. In addition, most of the experiments were conducted in preclinical and therefore translation of these results from bench to bed requires more effort in this field. Exosomes from stem cells are a promising tool for the treatment of ischemic diseases. In addition, translation of pre-clinic results into clinic needs further studies in this field.

Diabetic vasculopathy: macro and microvascular injury

PURPOSE OF REVIEW

Diabetes is a common and prevalent medical condition as it affects many lives around the globe. Specifically, type-2 Diabetes (T2D) is characterized by chronic systemic inflammation alongside hyperglycemia and insulin resistance in the body, which can result in atherosclerotic legion formation in the arteries and thus progression of related conditions called diabetic vasculopathies. T2D patients are especially at risk for vascular injury; adjunct in many of these patients heir cholesterol and triglyceride levels reach dangerously high levels and accumulate in the lumen of their vascular system.

RECENT FINDINGS

Microvascular and macrovascular vasculopathies as complications of diabetes can accentuate the onset of organ illnesses, thus it is imperative that research efforts help identify more effective methods for prevention and diagnosis of early vascular injuries. Current research into vasculopathy identification/treatment will aid in the amelioration of diabetes-related symptoms and thus reduce the large number of deaths that this disease accounts annually.

SUMMARY

This review aims to showcase the evolution and effects of diabetic vasculopathy from development to clinical disease as macrovascular and microvascular complications with a concerted reference to sex-specific disease progression as well.

Sulodexide improves pain-free walking distance in patients with lower extremity peripheral arterial disease: A systematic review and meta-analysis

Peripheral arterial disease is associated with very high cardiovascular risk. The main symptom is intermittent claudication, which strongly affects the quality of life. Therefore, treatment goals in peripheral arterial disease consist of the reduction of cardiovascular events and the relief of symptoms. An increase in pain-free walking distance, evaluated based on the Initial Claudication Distance, was also a strong positive prognostic factor in patients with peripheral arterial disease. Our objective was to reassess whether sulodexide is effective in improving Initial Claudication Distance. For this, we searched the literature according to the PRISMA checklist for double blind clinical trials assessing the improvement in the Initial Claudication Distance after 90 days of standard therapeutic regimen with sulodexide in adult patients with peripheral arterial disease. We found and assessed for bias in 11 studies eligible for review and meta-analysis. Data extracted from those studies favoured the sulodexide group, showing an overall difference in Initial Claudication Distance of +68.9 (CI 95%; ± 11.9 m) at the end of treatment (p < 0.001). According to this review, sulodexide is effective in improving Initial Claudication Distance and consequently the quality of life in patients with peripheral arterial disease. Further studies are needed to assess the effects of this drug on disease progression in asymptomatic patients with peripheral arterial disease.

Tackling Elevated Risk in PAD: Focus on Antithrombotic and Lipid Therapy for PAD

The PAD population is at increased risk of major adverse cardiovascular events (MACE) and major adverse limb events (MALE). Risk factor modification, symptom control, antithrombotic, and lipid therapies are the mainstays of PAD medical therapy. Recent data has challenged prior recommendations regarding the optimal secondary prevention strategies in PAD. PURPOSE OF REVIEW: To review clinical evidence from large randomized controlled trials showing the benefit of antithrombotic and lipid therapy in the PAD population. RECENT FINDINGS: The COMPASS trial challenged prior recommendations regarding anticoagulation in PAD. Among the PAD subgroup, rivaroxaban 2.5 mg plus aspirin reduced MACE (HR 0.72, 95% CI 0.57-0.90, p = 0.0047), MALE (HR 0.54, 95% CI 0.35-0.82, p = 0.0037), and major amputation (HR 0.30, 95% CI 0.11-0.80, p = 0.011) compared with aspirin monotherapy. The THEMIS trial showed a 55% risk reduction for MALE with ticagrelor DAPT compared with aspirin monotherapy (HR 0.45, 95% CI 0.23-0.86). The FOURIER trial revealed that lowering LDL cholesterol below current targets with a PCSK9 inhibitor reduced MACE (HR 0.73, 95% CI 0.59-0.91, p = 0.0040) and MALE (HR 0.43, 95% CI 0.19-0.99, p = 0.042) in subjects with symptomatic PAD. Recent high-quality evidence shows the benefit of antiplatelet therapy, anticoagulation therapy, and lipid therapy in reducing MACE and MALE in PAD. Despite these findings, implementation remains a challenge and focus should now shift towards adopting evidence-based recommendations in clinical practice.

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.

Peripheral Artery Disease: Past, Present, and Future

Peripheral artery disease is a prevalent but underdiagnosed manifestation of atherosclerosis. There is insufficient awareness of its clinical manifestations, including intermittent claudication and critical limb ischemia and of its risk of adverse cardiovascular and limb outcomes. In addition, our inadequate knowledge of its pathophysiology has also limited the development of effective treatments, particularly in the presence of critical limb ischemia. This review aims to highlight essential elements of the epidemiology and pathophysiology of peripheral artery disease, bring attention to the often-atypical manifestations of occlusive arterial disease of the lower extremity, increase awareness of critical limb ischemia, briefly describe the diagnostic role of the ankle brachial index, and go over the contemporary management of peripheral artery disease. An emphasis is placed on evidence-based medical treatments to improve symptoms and quality of life and to reduce the risk of cardiovascular and limb events in these patients, including supervised exercise training, smoking cessation, antagonism of the renin-angiotensin system, lipid-lowering, antiplatelet, and antithrombotic therapies.

Paclitaxel-Based Devices for the Treatment of PAD: Balancing Clinical Efficacy with Possible Risk

PURPOSE OF REVIEW

Paclitaxel-based endovascular devices have become the standard of care in symptomatic, medication-refractory peripheral artery disease (PAD) and in critical limb ischemia (CLI). This review examines the data on the efficacy and safety of these devices relative to standard balloon angioplasty (PTA) and bare metal stents (BMS).

RECENT FINDINGS

Randomized controlled trials (RCTs) have found that peripheral devices coated with paclitaxel result in superior patency rates and decreased target lesion revascularization (TLR) compared with non-drug-coated devices. Recently, a meta-analysis of randomized controlled trials unexpectedly reported an increase in mortality in patients treated with paclitaxel-coated devices (PCDs), resulting in the pausing of ongoing trials and a warning of safety from the FDA. Observational data that has been published since this time has not supported this safety concern. PAD is a common disease that severely impacts quality and length of life. PCDs are a promising therapy for patients with PAD, offering a more effective and durable intervention when compared with traditional PTA/BMS. A meta-analysis of RCTs identified a signal of harm with these devices which has now been replicated by the FDA. However, there is significant missing data from the trials analyzed by the meta-analysis and FDA, no plausible mechanism linking paclitaxel to death, and no correlation between paclitaxel dose and mortality. Analyses in observational data have found no safety signal. An FDA panel evaluating the validity of this late-mortality signal recently adjourned, emphasizing that the available data is incomplete. PCDs will remain on the market, and an active discussion is underway for developing an approach for improved post-market surveillance, device-labeling, and cause of death adjudication.

Therapeutic angiogenesis using stem cell-derived extracellular vesicles: an emerging approach for treatment of ischemic diseases

Ischemic diseases, which are caused by a reduction of blood supply that results in reduced oxygen transfer and nutrient uptake, are becoming the leading cause of disabilities and deaths. Therapeutic angiogenesis is key for the treatment of these diseases. Stem cells have been used in animal models and clinical trials to treat various ischemic diseases. Recently, the efficacy of stem cell therapy has increasingly been attributed to exocrine functions, particularly extracellular vesicles. Extracellular vesicles are thought to act as intercellular communication vehicles to transport informational molecules including proteins, mRNA, microRNAs, DNA fragments, and lipids. Studies have demonstrated that extracellular vesicles promote angiogenesis in cellular experiments and animal models. Herein, recent reports on the use of extracellular vesicles for therapeutic angiogenesis during ischemic diseases are presented and discussed. We believe that extracellular vesicles-based therapeutics will be an ideal treatment method for patients with ischemic diseases.

[Clinical study of efficacy and safety of Aducil in patients with chronic lower limb ischaemia]

AIM

The study was aimed at assessing efficacy and safety of treatment with Aducil® (cilostazol) compared with Trental® 400 in patients with moderate-to-severe intermittent claudication due to peripheral atherosclerosis.

PATIENTS AND METHODS

The study included a total of one hundred and forty-five 36-to-75-year-old patients. The participants were distributed into 2 groups according to the inclusion/exclusion criteria in a 2 to 1 proportion: patients in group 1 received Aducil® 100 mg BID, in group 2 - Trental® 400 TID for 12 weeks. 142 subjects completed the protocol.

RESULTS

Analysis of the effectiveness of treatment according to the primary criterion showed a better effectiveness of Aducil® as compared with Trental® 400. Subjects who received Aducil® had a higher increase in the absolute maximum walking distance after 12 weeks of treatment as compared with those taking Trental® 400: 126±110 m versus 45±39 m, respectively (р<0.001). Subjects who received Aducil® had a statistically significant improvement in quality of life parameters such as physical and mental health components according to the SF-36 questionnaire after 12 weeks of treatment (р≤0.01). Subjects in Aducil® group had better quality of life with an increase from 34 to 40 points according to the physical component score, while patients in Trental® 400 group demonstrated minor positive changes (from 35 to 37 points); mean mental component score increased from 45 to 48 points in Aducil® group as compared with an increase from 45 to 47 points in Trental® 400 group. While self-reported physical health status was similar between the groups at baseline, subjects in Aducil® group reported better physical functioning after treatment (р=0.016). Two adverse events were registered in two subjects in Aducil® group.

CONCLUSION

Analysis of the study endpoints demonstrated that Aducil® had better treatment effectiveness in patients with chronic lower limb ischemia stage IIB according to the classification of A.V. Pokrovsky-Fontaine as compared with Trental® 400, while the safety profile and drug tolerance were similar between the two.

Long-lasting anti-platelet activity of cilostazol from poly(ε-caprolactone)-poly(ethylene glycol) blend nanocapsules

Cilostazol (CLZ) acts as a vasodilator and antiplatelet agent and is the main drug for the treatment of intermittent claudication (IC) related to peripheral arterial disease (PAD). The usual oral dose is 100 mg twice a day, which represents a disadvantage in treatment compliance. CLZ presents several side effects, such as headache, runny nose, and dizziness. This paper aimed to obtain novel polymeric nanocapsules prepared from poly(ε-caprolactone)-poly(ethylene glycol) (PCL-PEG) blend containing CLZ. Nanocapsules showed pH values between 6.1 and 6.3, average size lower than 137 nm, low polydispersity index (<0.22) and negative zeta potential. These nanoformulations demonstrated spherical shape with smooth surface. Results achieved by X-ray diffraction (XRD) and differential scanning calorimetry (DSC) indicated drug amorphization compared to pure CLZ. Fourier-transformed infrared spectroscopy (FTIR) showed no chemical bonds between drug and polymers. Formulations presented suitable stability for physical parameters. The in vitro drug release demonstrated prolonged release with no burst effect. Drug release was controlled by both mechanisms of polymer relaxation/degradation and Fickian diffusion. Moreover, chosen CLZ-loaded nanocapsules provided an in vivo prolonged antiplatelet effect for CLZ statistically similar to aspirin. These formulations can be further used as a feasible oral drug delivery carrier for controlled release of CLZ in order to treat PAD and IC events.

Ticagrelor in Peripheral Artery Disease Endovascular Revascularization (TI-PAD): Challenges in clinical trial execution

There is limited evidence to guide clinical decision-making for antiplatelet therapy in peripheral artery disease (PAD) in the setting of lower extremity endovascular treatment. The Ticagrelor in Peripheral Artery Disease Endovascular Revascularization Study (TI-PAD) evaluated the role of ticagrelor versus aspirin as monotherapy in the management of patients following lower extremity endovascular revascularization. The trial failed to recruit the targeted number of patients, likely due to aspects of the design including the lack of option for dual antiplatelet therapy, and inability to identify suitable patients at study sites. In response, the protocol underwent amendments, but these changes did not adequately stimulate recruitment, and thus TI-PAD was prematurely terminated. This article describes the rationale for TI-PAD and challenges in trial design, subject recruitment and trial operations to better inform the conduct of future trials in PAD revascularization. ClinicalTrials.gov Identifier: NCT02227368.

Gender Differences in Peripheral Vascular Disease

In the past 20 years, peripheral artery disease (PAD) has been increasingly recognized as a significant cause of morbidity and mortality in the United States. PAD has traditionally been identified as a male-dominant disease; however, recent population trends and studies in PAD suggest that women are affected at least as often as men. Women comprise a larger population of the elderly than men, as well as an increasing proportion of patients with PAD. Much of the existing research on PAD has focused on whole populations, and gender-specific data on PAD is sparse. This review focuses on gender-specific differences in presentation, management, and outcomes of PAD intervention that are important considerations for the interventional radiologist.

Functions of PDE3 Isoforms in Cardiac Muscle

Isoforms in the PDE3 family of cyclic nucleotide phosphodiesterases have important roles in cyclic nucleotide-mediated signalling in cardiac myocytes. These enzymes are targeted by inhibitors used to increase contractility in patients with heart failure, with a combination of beneficial and adverse effects on clinical outcomes. This review covers relevant aspects of the molecular biology of the isoforms that have been identified in cardiac myocytes; the roles of these enzymes in modulating cAMP-mediated signalling and the processes mediated thereby; and the potential for targeting these enzymes to improve the profile of clinical responses.

Disruption of mitochondrial quality control in peripheral artery disease: New therapeutic opportunities

Peripheral artery disease (PAD) is a multifactorial disease initially triggered by reduced blood supply to the lower extremities due to atherosclerotic obstructions. It is considered a major public health problem worldwide, affecting over 200 million people. Management of PAD includes smoking cessation, exercise, statin therapy, antiplatelet therapy, antihypertensive therapy and surgical intervention. Although these pharmacological and non-pharmacological interventions usually increases blood flow to the ischemic limb, morbidity and mortality associated with PAD continue to increase. This scenario raises new fundamental questions regarding the contribution of intrinsic metabolic changes in the distal affected skeletal muscle to the progression of PAD. Recent evidence suggests that disruption of skeletal muscle mitochondrial quality control triggered by intermittent ischemia-reperfusion injury is associated with increased morbidity in individuals with PAD. The mitochondrial quality control machinery relies on surveillance systems that help maintaining mitochondrial homeostasis upon stress. In this review, we describe some of the most critical mechanisms responsible for the impaired skeletal muscle mitochondrial quality control in PAD. We also discuss recent findings on the central role of mitochondrial bioenergetics and quality control mechanisms including mitochondrial fusion-fission balance, turnover, oxidative stress and aldehyde metabolism in the pathophysiology of PAD, and highlight their potential as therapeutic targets.

Peripheral Artery Disease: Evolving Role of Exercise, Medical Therapy, and Endovascular Options

The prevalence of peripheral artery disease (PAD) continues to increase worldwide. It is important to identify patients with PAD because of the increased risk of myocardial infarction, stroke, and cardiovascular death and impaired quality of life because of a profound limitation in exercise performance and the potential to develop critical limb ischemia. Despite effective therapies to lower the cardiovascular risk and prevent progression to critical limb ischemia, patients with PAD continue to be under-recognized and undertreated. The management of PAD patients should include an exercise program, guideline-based medical therapy to lower the cardiovascular risk, and, when revascularization is indicated, an "endovascular first" approach. The indications and strategic choices for endovascular revascularization will vary depending on the clinical severity of the PAD and the anatomic distribution of the disease. In this review, we discuss an evidence-based approach to the management of patients with PAD.

The Ankle Brachial Index Exhibits Better Association of Cardiovascular Prognosis Than Non-High-Density Lipoprotein Cholesterol in Type 2 Diabetes

OBJECTIVE

The association between ankle brachial index (ABI) and outcomes in diabetic subjects is controversial. The purpose of this study was to evaluate whether the ABI is more strongly associated with cardiovascular outcomes comparing with non-high-density lipoprotein cholesterol (non-HDL-c).

RESEARCH DESIGN AND METHODS

A total of 452 type 2 diabetic subjects followed up for a mean of 5.8 years were grouped by ABI (<0.9 versus ≥0.9) and non-HDL-c (<100mg/dL versus ≥100mg/dL). Primary outcomes were composite events including all-cause mortality, hospitalization for coronary artery disease, stroke, revascularization, amputation and diabetic foot, and the secondary end point was all-cause mortality.

RESULTS

Intergroup differences in percentage of men, duration of diabetes, hemoglobin A1c, total cholesterol, low-density lipoprotein cholesterol, triglycerides and estimated glomerular filtration rate were significant. A total of 64 composite events and 17 deaths were recorded. A higher number of composite events occurred in the group with abnormal ABI but optimal non-HDL-c than in those with suboptimal non-HDL-c but normal ABI (29% versus 11%, P < 0.05). A similar trend was observed in all-cause mortality (11% versus 1%, P < 0.05). The ABI was the dominant risk factor for both end points after adjusting other factors (for composite events, hazard ratio = 0.02, 95% CI: 0.00-0.10, P < 0.001 and for all-cause mortality, hazard ratio = 0.01, 95% CI: 0.00-0.28, P = 0.006).

CONCLUSIONS

The ABI was more strongly associated with outcomes in diabetes than non-HDL-c. The ABI should be routinely screened in diabetes even without symptom.

Effects of oral N-acetylcysteine on walking capacity, leg reactive hyperemia, and inflammatory and angiogenic mediators in patients with intermittent claudication

Increased oxidative stress and inflammation contribute to impaired walking capacity and endothelial dysfunction in patients with intermittent claudication (IC). The goal of the study was to determine the effects of oral treatment with the antioxidant N-acetylcysteine (NAC) on walking capacity, leg postocclusive reactive hyperemia, circulating levels of inflammatory mediators, and whole blood expression of angiogenic mediators in patients with IC. Following a double-blinded randomized crossover design, 10 patients with IC received NAC (1,800 mg/day for 4 days plus 2,700 mg before the experimental session) and placebo (PLA) before undergoing a graded treadmill exercise test. Leg postocclusive reactive hyperemia was assessed before and after the test. Blood samples were taken before and after NAC or PLA ingestions and 5 and 30 min after the exercise test for the analysis of circulating inflammatory and angiogenic markers. Although NAC increased the plasma ratio of reduced to oxidized glutathione, there were no differences between experimental sessions for walking tolerance and postocclusive reactive hyperemia. Plasma concentrations of soluble vascular cell adhesion protein-1, monocyte chemotactic protein-1, and endothelin-1 increased similarly following maximal exercise after PLA and NAC (P < 0.001). Whole blood expression of pro-angiogenic microRNA-126 increased after maximal exercise in the PLA session, but treatment with NAC prevented this response. Similarly, exercise-induced changes in whole blood expression of VEGF, endothelial nitric oxide synthase and phosphatidylinositol 3-kinase R2 were blunted after NAC. In conclusion, oral NAC does not increase walking tolerance or leg blood flow in patients with IC. In addition, oral NAC prevents maximal exercise-induced increase in the expression of circulating microRNA-126 and other angiogenic mediators in patients with IC.

Contemporary medical management of peripheral arterial disease: a focus on risk reduction and symptom relief for intermittent claudication

Peripheral arterial disease (PAD) is primarily caused by progressive systemic atherosclerosis manifesting in the lower extremities. This review addresses the epidemiology, clinical presentation and evaluation, and medical management of PAD, with a focus on intermittent claudication. Key advances in the recognition of cardiovascular risk in asymptomatic individuals with mildly abnormal ankle-brachial index, newer reflections on exercise therapy, and a review of established and investigational agents for the treatment of symptomatic PAD, such as cilostazol, statins, and angiotensin-converting enzyme inhibitors, are highlighted.

Pathogenesis of the limb manifestations and exercise limitations in peripheral artery disease

Patients with peripheral artery disease have a marked reduction in exercise performance and daily ambulatory activity irrespective of their limb symptoms of classic or atypical claudication. This review will evaluate the multiple pathophysiologic mechanisms underlying the exercise impairment in peripheral artery disease based on an evaluation of the current literature and research performed by the authors. Peripheral artery disease results in atherosclerotic obstructions in the major conduit arteries supplying the lower extremities. This arterial disease process impairs the supply of oxygen and metabolic substrates needed to match the metabolic demand generated by active skeletal muscle during walking exercise. However, the hemodynamic impairment associated with the occlusive disease process does not fully account for the reduced exercise impairment, indicating that additional pathophysiologic mechanisms contribute to the limb manifestations. These mechanisms include a cascade of pathophysiological responses during exercise-induced ischemia and reperfusion at rest that are associated with endothelial dysfunction, oxidant stress, inflammation, and muscle metabolic abnormalities that provide opportunities for targeted therapeutic interventions to address the complex pathophysiology of the exercise impairment in peripheral artery disease.

Endovascular intervention for peripheral artery disease

Advances in endovascular therapies during the past decade have broadened the options for treating peripheral vascular disease percutaneously. Endovascular treatment offers a lower risk alternative to open surgery in many patients with multiple comorbidities. Noninvasive physiological tests and arterial imaging precede an endovascular intervention and help localize the disease and plan the procedure. The timing and need for revascularization are broadly related to the 3 main clinical presentations of claudication, critical limb ischemia, and acute limb ischemia. Many patients with claudication can be treated by exercise and medical therapy. Endovascular procedures are considered when these fail to improve quality of life and function. In contrast, critical limb ischemia and acute limb ischemia threaten the limb and require more urgent revascularization. In general, endovascular treatments have greater long-term durability for aortoiliac disease than femoral popliteal disease. Infrapopliteal revascularization is generally reserved for critical and acute limb ischemia. Balloon angioplasty and stenting are the mainstays of endovascular therapy. New well-tested innovations include drug-eluting stents and drug-coated balloons. Adjunctive devices for crossing chronic total occlusions or debulking plaque with atherectomy are less rigorously studied and have niche roles. Patients receiving endovascular procedures need a structured surveillance plan for follow-up care. This includes intensive treatment of cardiovascular risk factors to prevent myocardial infarction and stroke, which are the main causes of death. Limb surveillance aims to identify restenosis and new disease beyond the intervened segments, both of which may jeopardize patency and lead to recurrent symptoms, functional impairment, or a threatened limb.

Percutaneous versus surgical management of lower extremity peripheral artery disease

Lower extremity peripheral artery disease (PAD) is highly prevalent and can manifest as intermittent claudication or, in the most advanced form, critical limb ischemia. Revascularization, which can be accomplished by an endovascular or surgical approach, is performed to improve quality of life or, in severe cases, for limb salvage. Over the past decade, percutaneous catheter-based techniques have improved such that acute procedural success is high even in complex anatomy. Patency rates have also increased with the use of atherectomy devices and drug-eluting stents. Often, patients with PAD have comorbidities that increase the risk of cardiovascular complications with surgical procedures. These factors have led to the adoption of an endovascular first strategy with surgical management reserved for selected patients. This review focuses on the most current clinical trials of endovascular therapy for PAD. In addition, older but relevant studies comparing endovascular and surgical approaches and contemporary surgical trials are presented for reference.

Pharmacological Treatment and Current Management of Peripheral Artery Disease

Patients with peripheral artery disease (PAD) are at heightened risk of both systemic cardiovascular adverse events, as well as limb-related morbidity. The optimal management of patients with PAD requires a comprehensive treatment strategy incorporating both lifestyle changes, including smoking cessation and exercise, as well as optimal medical therapy. Pharmacological therapies for patients with PAD are targeted both at modifying broad risk factors for major adverse cardiovascular events, as well as reducing limb-related morbidity. Observational data suggest that indicated pharmacological treatments are greatly underutilized in PAD, underscoring the need for improvements in patient identification and care delivery. Ongoing trials of novel therapies in patients with PAD will further inform pharmacological strategies to reduce both systemic cardiovascular risk and limb-related morbidity.

Efficacy of two different self-expanding nitinol stents for atherosclerotic femoropopliteal arterial disease (SENS-FP trial): study protocol for a randomized controlled trial

Background

There have been few randomized control trials comparing the incidence of stent fracture and primary patency among different self-expanding nitinol stents to date. The SMART™ CONTROL stent (Cordis Corp, Miami Lakes, Florida, United States) has a peak-to-valley bridge and inline interconnection, whereas the COMPLETE™-SE stent (Medtronic Vascular, Santa Rosa, California, United States) crowns have been configured to minimize crown-to-crown interaction, increasing the stent's flexibility without compromising radial strength. Further, the 2011 ESC (European society of cardiology) guidelines recommend that dual antiplatelet therapy with aspirin and a thienopyridine such as clopidogrel should be administered for at least one month after infrainguinal bare metal stent implantation. Cilostazol has been reported to reduce intimal hyperplasia and subsequent repeat revascularization. To date, there has been no randomized study comparing the safety and efficacy of two different antiplatelet regimens, clopidogrel and cilostazol, following successful femoropopliteal stenting.

Methods/Design

The primary purpose of our study is to examine the incidence of stent fracture and primary patency between two different major representative self-expanding nitinol stents (SMART™ CONTROL versus COMPLETE™-SE) in stenotic or occlusive femoropopliteal arterial lesion. The secondary purpose is to examine whether there is any difference in efficacy and safety between aspirin plus clopidogrel versus aspirin plus cilostazol for one month following stent implantation in femoropopliteal lesions. This is a prospective, randomized, multicenter trial to assess the efficacy of the COMPLETE™-SE versus SMART™ CONTROL stent for provisional stenting after balloon angioplasty in femoropopliteal arterial lesions. The study design is a 2x2 randomization design and a total of 346 patients will be enrolled. The primary endpoint of this study is the rate of binary restenosis in the treated segment at 12 months after intervention as determined by catheter angiography or duplex ultrasound.

Discussion

This trial will provide powerful insight into whether the design of the COMPLETE™-SE stent is more fracture-resistant or effective in preventing restenosis compared with the SMART™ CONTROL stent. Also, it will determine the efficacy and safety of aspirin plus clopidogrel versus aspirin plus cilostazol in patients undergoing stent implantation in femoropopliteal lesions.

Trial registration

Registered on 2 April 2012 with the National Institutes of Health Clinical Trials Registry (ClinicalTrials.gov identifier# NCT01570803).

Association of monocyte tumor necrosis factor α expression and serum inflammatory biomarkers with walking impairment in peripheral artery disease

OBJECTIVE

Inflammation contributes to the development of peripheral artery disease (PAD) and may contribute to intermittent claudication by adversely affecting vascular and skeletal muscle function. We explored the association of inflammation to maximal walking time (MWT) in patients with claudication.

METHODS

Circulating inflammatory biomarkers, including tumor necrosis factor α (TNF-α), C-reactive protein (CRP), interleukin-6 (IL-6), and soluble intercellular adhesion molecule 1 (sICAM), were measured in 75 subjects with intermittent claudication as well as in 43 healthy subjects. Real-time polymerase chain reaction was used to quantify mRNA expression of TNF-α, IL-6, interferon-γ, and CD36 from peripheral blood monocytes. Treadmill testing was performed in PAD subjects to assess MWT.

RESULTS

Compared with healthy subjects, PAD subjects had higher levels of circulating TNF-α (P < .0001), CRP (P = .003), sICAM (P < .0001), and IL-6 (P < .0001). Expression of both IL-6 (P = .024) and CD36 (P = .018) was greater in PAD subjects than in healthy subjects. Among subjects with PAD, higher gene expression of TNF-α was associated inversely with MWT (P = .01). MWT was also associated inversely with greater levels of circulating TNF-α (P = .028), CRP (P = .024), IL-6 (P = .03), and sICAM (P = .018).

CONCLUSIONS

Systemic inflammation, as indicated by TNF-α inflammatory gene expression in peripheral blood monocytes and by circulating biomarker levels, is associated with impairment in walking time in patients with PAD and intermittent claudication.

Role of the latest endovascular technology in the treatment of intermittent claudication

Intermittent claudication is a serious symptom in patients with peripheral arterial disease, and severely limits activities of daily living. Conservative treatment (optimal medical therapy and exercise rehabilitation programs) and revascularization procedures (endovascular treatment [EVT] or open bypass surgery) can relieve intermittent claudication. Among these treatment options, EVT has developed dramatically during the past decade, and has enabled physicians to offer less invasive treatment options with increasing durability. EVT for aortoiliac lesions has matured, and its long-term patency now approaches that of open bypass surgery. The latest EVT technologies include drug-eluting stents, stent grafts, drug-coated balloons, and bioresorbable stents. The recently reported patency of stent grafts in the femoropopliteal lesions was comparable with that of the prosthetic bypass graft. In the course of the paradigm shift from bypass surgery to EVT, evidence of any long-term benefit of EVT compared with supervised exercise is still inconclusive. EVT could improve walking performance in the short-term, while supervised exercise could improve walking performance more efficiently in the long-term. Combined treatment with EVT and exercise may offer the most sustainable and effective symptom relief. This paper reviews the relevant literature on the treatment of intermittent claudication, focusing on the latest EVT technologies, and outlines a strategy for achieving long-term benefits.

Cilostazol and outcome in outpatients with peripheral artery disease

BACKGROUND

Cilostazol increases the walking distance in patients with intermittent claudication, but there is scarce evidence of any effect on the risk for subsequent ischemic events, bleeding or death.

PATIENTS AND METHODS

We used data from the FRENA Registry to compare the clinical outcome in stable outpatients with intermittent claudication, according to the use of cilostazol.

RESULTS

As of January 2013, 1,317 patients with intermittent claudication were recruited in FRENA, of whom 191 (14.5%) received cilostazol. Over a mean follow-up of 18months, 39 patients developed myocardial infarction, 23 ischemic stroke, 20 underwent limb amputation, 15 had major bleeding and 70 died. There were no significant differences in the rate of subsequent ischemic events, major bleeding or death between patients receiving or not receiving cilostazol. On multivariate analysis, the use of cilostazol had no influence on the risk for subsequent myocardial infarction (hazard ratio [HR]: 0.97; 95% CI: 0.33-20.8), ischemic stroke (HR: 1.46; 95% CI: 0.48-4.43), limb amputation (HR: 0.34; 95% CI: 0.04-20.6), major bleeding (HR: 1.52; 95% CI: 0.33-7.09) or death (HR: 0.90; 95% CI: 0.40-20.0).

CONCLUSIONS

In stable outpatients with intermittent claudication, the use of cilostazol was not associated with increased rates of subsequent ischemic events, major bleeding or death.

Challenges associated with peripheral arterial disease in women

Peripheral arterial disease (PAD) is an increasingly recognized disorder that is associated with functional impairment, quality-of-life deterioration, increased risk of cardiovascular ischemic events, and increased risk of total and cardiovascular mortality. Although earlier studies suggested that PAD was more common in men, recent reports based on more sensitive tests have shown that the prevalence of PAD in women is at least the same as in men, if not higher. PAD tends to present itself asymptomatically or with atypical symptoms more frequently in women than in men, and is associated with comorbidities or situations particularly or exclusively found in the female sex, such as osteoporosis, hypothyroidism, the use of oral contraceptives, and a history of complications during pregnancy. Fat-distribution patterns and differential vascular characteristics in women may influence the interpretation of diagnostic methods, whereas sex-related vulnerability to drugs typically used in subjects with PAD, differences in risk-factor distribution among sexes, and distinct responses to revascularization procedures in men and women must be taken into account for proper disease management. All these issues pose important challenges associated with PAD in women. Of note, this group has classically been underrepresented in research studies. As a consequence, several sex-related challenges regarding diagnosis and management issues should be acknowledged, and research gaps should be addressed in order to successfully deal with this major health issue.