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Background: Peripheral artery disease (PAD) is important to public health as a major contributor to cardiovascular morbidity and mortality. Recent developments in magnetic resonance imaging (MRI) techniques permit improved assessment of PAD anatomy and physiology, and may serve as surrogate end points after proangiogenic therapies.Methods: The PACE study is a randomized, double-blind, placebo-controlled clinical trial designed to assess the physiologic impact and potential clinical efficacy of autologous bone marrow-derived ALDHbr stem cells. The primary MRI end points of the study are as follows: (1) total collateral count, (2) calf muscle plasma volume (a measure of capillary perfusion) by dynamic contrast-enhanced MRI, and (3) peak hyperemic popliteal flow by phase-contrast MRI (PC-MRI).Results: The interreader and intrareader and test-retest results demonstrated good-to-excellent reproducibility (interclass correlation coefficient range 0.61-0.98) for all magnetic resonance measures. The PAD participants (n=82) had lower capillary perfusion measured by calf muscle plasma volume (3.8% vs 5.6%) and peak hyperemic popliteal flow (4.1 vs 13.5mL/s) as compared with the healthy participants (n=16), with a significant level of collateralization.Conclusions: Reproducibility of the MRI primary end points in PACE was very good to excellent. The PAD participants exhibited decreased calf muscle capillary perfusion as well as arterial flow reserve when compared with healthy participants. The MRI tools used in PACE may advance PAD science by enabling accurate measurement of PAD microvascular anatomy and perfusion before and after stem cell or other PAD therapies. [ABSTRACT FROM AUTHOR]

Background Peripheral artery disease (PAD) is a major cause of cardiovascular ischemic events and amputation. Knowledge gaps exist in defining and measuring key factors that predict these events. The objective of this study was to assess whether duration of limb ischemia would serve as a major predictor of limb and patient survival. Methods The FReedom from Ischemic Events: New Dimensions for Survival (FRIENDS) registry enrolled consecutive patients with limb-threatening peripheral artery disease at a single tertiary care hospital. Demographic information, key clinical care time segments, functional status and use of revascularization, and pharmacotherapy data were collected at baseline, and vascular ischemic events, cardiovascular mortality, and all-cause mortality were recorded at 30 days and 1 year. Results A total of 200 patients with median (interquartile range) age of 76 years (65-84 years) were enrolled in the registry. Median duration of limb ischemia was 0.75 days for acute limb ischemia (ALI) and 61 days for chronic critical limb ischemia (CLI). Duration of limb ischemia of <12, 12 to 24, and >24 hours in patients with ALI was associated with much higher rates of first amputation ( P = .0002) and worse amputation-free survival ( P = .037). No such associations were observed in patients with CLI. Conclusions For individuals with ischemic symptoms <14 days, prolonged limb ischemia is associated with higher 30-day and 1-year amputation, systemic ischemic event rates, and worse amputation-free survival. No such associations are evident for individuals with chronic CLI. These data imply that prompt diagnosis and revascularization might improve outcomes for patients with ALI. [ABSTRACT FROM AUTHOR]

Peripheral artery disease (PAD) is recognized as a public health issue because of its prevalence, functional limitations, and increased risk of systemic ischemic events. Current treatments for claudication, the primary symptom in patients with PAD, have limitations. Cells identified using cytosolic enzyme aldehyde dehydrogenase (ALDH) may benefit patients with severe PAD but has not been studied in patients with claudication. PACE is a randomized, double-blind, placebo-controlled clinical trial conducted by the Cardiovascular Cell Therapy Research Network to assess the safety and efficacy of autologous bone marrow–derived ALDH br cells delivered by direct intramuscular injections in 80 patients with symptom-limiting intermittent claudication. Eligible patients will have a significant stenosis or occlusion of infrainguinal arteries and a resting ankle-brachial index less than 0.90 and will be randomized 1:1 to cell or placebo treatment with a 1-year follow-up. The primary end points are the change in peak walking time and leg collateral arterial anatomy, calf muscle blood flow, and tissue perfusion as determined by magnetic resonance imaging at 6 months compared with baseline. The latter 3 measurements are new physiologic lower extremity tissue perfusion and PAD imaging–based end points that may help to quantify the biologic and mechanistic effects of cell therapy. This trial will collect important mechanistic and clinical information on the safety and efficacy of ALDH br cells in patients with claudication and provide valuable insight into the utility of advanced magnetic resonance imaging end points. [ABSTRACT FROM AUTHOR]

Background Critical limb ischemia (CLI) represents the most severe clinical manifestation of peripheral arterial disease (PAD) and is the major cause of ischemic amputation in the United States. Risk factors and the associated incidence and prevalence of CLI have not been well described in the general population. This study describes the risk factors for PAD progression to CLI and estimates the annual incidence and prevalence of CLI in a representative United States patient cohort. Methods This was a retrospective cohort analysis of adults with commercial, Medicare supplemental, or Medicaid health insurance who had at least one PAD or CLI health care claim from January 1, 2003, through December 31, 2008, and 12 months of continuous coverage. Two subgroups of CLI presentation were identified: primary CLI (patients without any prior PAD or subsequent PAD diagnostic code >30 days after CLI diagnostic code) and secondary CLI (patients with prior PAD or subsequent PAD diagnostic codes ≤30 days of a CLI diagnostic code). Patterns of presentation, annual incidence, and prevalence of CLI were stratified by health care plan. Risk factors for progression to CLI were compared by presentation type. Results From 2003 to 2008, the mean annual incidence of PAD was 2.35% (95% confidence interval [CI], 2.34%-2.36%) and the incidence of CLI was 0.35% (95% CI, 0.34%-0.35%) of the eligible study population, with primary and secondary presentations occurring at similar rates. The mean annualized prevalence of PAD was 10.69% (95% CI, 10.67%10.70%) and the mean annualized prevalence of CLI was 1.33% (95% CI, 1.32%-1.34%) of the eligible study population, and two-thirds of the cases presented as secondary CLI. CLI developed in 11.08% (95% CI, 11.30%-11.13%) of patients with PAD. A multivariable model demonstrated that diabetes, heart failure, stroke, and renal failure were stronger predictors of primary rather than secondary CLI presentation. Conclusions These data establish new national estimates of the incidence and prevalence of CLI and define key risk factors that contribute to primary or secondary presentations of CLI within a very large contemporary insured population cohort in the United States. [ABSTRACT FROM AUTHOR]

Objective: To explore the relationship between gender, native artery diameters, and outcomes of stent revascularization (ST) in the "Claudication: Exercise versus Endoluminal Revascularization" trial. Methods: A comparative analysis was performed of the impact of gender, age, weight, height, body mass index, and body surface area on revascularization outcomes at baseline and 6 months in 55 arterial segments of aorta, common iliac artery, and external iliac artery (EIA). Results: Women demonstrated smaller diameter of the EIA. However, the clinical outcomes of revascularization were not negatively affected by the gender-based differences. Conclusion: Gender-based differences are unlikely to significantly impact outcome of ST. [ABSTRACT FROM AUTHOR]

Background: Tobacco use is an important preventable cause of peripheral artery disease (PAD) and a major determinant of adverse clinical outcomes.Objectives: This study hypothesized that tobacco use by PAD patients would be associated with higher health care utilization and associated costs.Methods: We conducted a retrospective, cross-sectional study using 2011 claims data from the largest Minnesota health plan. The total cohort included individuals with 12 months of continuous enrollment and ≥ 1 PAD-related claim. Tobacco cessation pharmacotherapy billing codes were queried in a subgroup with pharmacy benefits. Outcomes were total costs, annual proportion of members hospitalized, and primary discharge diagnoses.Results: A PAD cohort of 22,203 was identified, comprising 1,995 (9.0%) tobacco users. A subgroup of 9,027 with pharmacy benefits included 1,158 (12.8%) tobacco users. The total cohort experienced 22,220 admissions. The pharmacy benefits subgroup experienced 8,152 admissions. Within 1 year, nearly one-half the PAD tobacco users were hospitalized, 35% higher than nonusers in the total cohort (p < 0.001) and 30% higher in the subgroup (p < 0.001). In both cohorts, users were more frequently admitted for peripheral or visceral atherosclerosis (p < 0.001), acute myocardial infarction (p < 0.001), and coronary heart disease (p < 0.05). Observed costs in the total cohort were $64,041 for tobacco users versus $45,918 for nonusers. Costs for tobacco users also were consistently higher for professional and facility-based care, persisting after adjustment for age, sex, comorbidities, and insurance type.Conclusions: Tobacco use in PAD is associated with substantial increases in PAD-related hospitalizations, coronary heart disease and PAD procedures, and significantly greater costs. The results suggest that immediate provision of tobacco cessation programs may be especially cost effective. [ABSTRACT FROM AUTHOR]

Background: Treatment for claudication that is due to aortoiliac peripheral artery disease (PAD) often relies on stent revascularization (ST). However, supervised exercise (SE) is known to provide comparable short-term (6-month) improvements in functional status and quality of life. Longer-term outcomes are not known.Objectives: The goal of this study was to report the longer-term (18-month) efficacy of SE compared with ST and optimal medical care (OMC).Methods: Of 111 patients with aortoiliac PAD randomly assigned to receive OMC, OMC plus SE, or OMC plus ST, 79 completed the 18-month clinical and treadmill follow-up assessment. SE consisted of 6 months of SE and an additional year of telephone-based exercise counseling. Primary clinical outcomes included objective treadmill-based walking performance and subjective quality of life.Results: Peak walking time improved from baseline to 18 months for both SE (5.0 ± 5.4 min) and ST (3.2 ± 4.7 min) significantly more than for OMC (0.2 ± 2.1 min; p < 0.001 and p = 0.04, respectively). The difference between SE and ST was not significant (p = 0.16). Improvement in claudication onset time was greater for SE compared with OMC, but not for ST compared with OMC. Many disease-specific quality-of-life scales demonstrated durable improvements that were greater for ST compared with SE or OMC.Conclusions: Both SE and ST had better 18-month outcomes than OMC. SE and ST provided comparable durable improvement in functional status and in quality of life up to 18 months. The durability of claudication exercise interventions merits its consideration as a primary PAD claudication treatment. [ABSTRACT FROM AUTHOR]