Clinical Trials in Peripheral Vascular Disease

Abstract

Background Tremendous advances have occurred in therapies for peripheral vascular disease (PVD); however, until recently it has not been possible to examine the entire clinical trial portfolio of studies for treatment of PVD (both arterial and venous disease). Methods and Results We examined interventional trials registered in ClinicalTrials.gov from October 2007 through September 2010 (n=40,970) and identified 676 (1.7%) PVD trials (n=493 arterial only, n=170 venous only, n=13 both arterial and venous). Most arterial studies investigated lower extremity peripheral artery disease and acute stroke (35% and 24%, respectively), while most venous studies examined deep vein thrombosis/pulmonary embolus prevention (42%) or venous ulceration (25%). A placebo-controlled trial design was used in 27% of the PVD trials, and 4% of the PVD trials excluded patients aged >65 years. Enrollment in at least 1 US site decreased from 51% in 2007 to 41% of trials in 2010. Compared with non-cardiology disciplines, PVD trials were more likely to be double-blinded, investigate use of devices and procedures, and have industry sponsorship and assumed funding source, and less likely to investigate drug and behavioral therapies. Geographic access to PVD clinical trials within the United States is limited to primarily large metropolitan areas. Conclusions PVD studies represent a small group of trials registered in ClinicalTrials.gov, despite the high prevalence of vascular disease in the general population. This low number, compounded by the decreasing number of PVD trials in the United States, is concerning and may limit the ability to inform current clinical practice of patients with PVD.

Rivaroxaban with or without aspirin in patients with stable peripheral or carotid artery disease: an international, randomised, double-blind, placebo-controlled trial

“…19,20 Finding effective and relatively safe antithrombotic regimens for patients with peripheral artery disease to decrease major adverse cardiovascular events and major adverse limb events with an acceptable bleeding profile has been challenging, and there have been few large clinical trials that have been done in patients with peripheral artery disease. 21 Moderate intensity vitamin K antagonist therapy with antiplatelet therapy is associated with a substantial increase in life-threatening bleedings, and no reduction in major adverse cardiovascular events or major adverse limb events. 7 Furthermore, single and dual antiplatelet regimens have not conclusively shown reductions in major adverse limb events.…”

Why Patients Know More About Cars Than Peripheral Artery Disease

“…At the time of this publication, we still have no level 1 data guiding us on the choice of postendovascular intervention antiplatelet therapy, and, ironically, the effect of aspirin has now emerged as a question in the PAD population! 10 Despite the sobering data presented by Subherwal et al,7 this comes as no surprise to those of us in the field. After all, we know that patients with PAD do not receive the same intensity of atherosclerotic risk factor intervention when compared with patients with isolated coronary heart disease.…”

“…7 Using the clinicaltrials.gov database, the extent of trials in the peripheral vascular realm represents a paltry 1.7% of all investigations. Admittedly, this may underestimate early-stage trials and also excludes, for reasons unclear to me, trials of dialysis access salvage interventions, a critically important and much needed area of research.…”

“…The process of device approval does not necessarily facilitate tackling the most dire of patient conditions. Pathways for device approval and reimbursement are often so murky and uncertain that sponsors either choose not to invest in such strategies or, as is further suggested by Subherwal et al, 7 take their initiatives offshore to international venues. Subberwal et al suggest that the percentage of trials including US patients dropped by 10% from 2007 to 2010.…”

Registry Assessment of Peripheral Interventional Devices (RAPID) ― Registry Assessment of Peripheral Interventional Devices Core Data Elements ―

“…1-3 Despite the increasing burden on the health care system, relatively few comparative effectiveness studies are being performed of patients with PAD in the United States. 4 Multiple efforts by professional societies, academia, industry partners, and the U.S. Food and Drug Administration (FDA) have recently been undertaken to better define the nomenclature and classification of how patients with PAD are evaluated and treated in clinical practice. 5-8 Despite these efforts, the current state of evaluating patients with PAD and more specifically of evaluating medical devices used for peripheral vascular intervention (PVI) remain challenging because of the heterogeneity of the disease process (eg, symptom classification, anatomic location of disease, severity of disease), the multiple physician specialties that care for these patients and perform PVI, the multitude of devices available to treat PAD globally, the lack of consensus about best treatment approaches, and the absence of a consensus regarding a PAD-PVI lexicon.…”