Blood Factors and Peripheral Arterial Disease Outcomes

To investigate associations between hemostatic and inflammatory blood factors and progression of lower extremity arterial ischemia and cardiovascular events in men and women with and without lower extremity peripheral arterial disease.

Study Overview

Detailed Description

BACKGROUND:

The pathophysiology of functional impairment in patients with lower extremity peripheral arterial disease (PAD) is not well understood. Although lower ankle brachial index (ABI) levels are associated with greater functional impairment, one study suggests that the ABI improves to a greater degree than functional impairment after lower extremity revascularization. A meta-analysis of exercise studies in intermittent claudication demonstrated no significant association between improved walking ability after exercise and change in calf blood flow or ABI. Thus, characteristics in addition to ABI appear to influence walking ability in PAD.

It has been hypothesized that chronic inflammation is a biological mechanism underlying the decline in physical function that occurs with aging. It was recently reported that higher levels of D-dimer (fibrin degradation product) and high-sensitivity C-reactive protein (hsCRP) are associated with greater objectively assessed functional limitations in persons with PAD, but functional limitations refer to specific abilities, such as objectively measured walking speed or balance, which are distinct from disability. Furthermore, functional limitations may not fully explain disability.

DESIGN NARRATIVE:

The prospective study assessed associations between hemostatic and inflammatory blood factors and progression of lower extremity arterial ischemia and cardiovascular events in 346 men and women with lower extremity peripheral arterial disease (PAD) and 203 men and women without PAD.The study was ancillary to an NHLBI funded prospective study of functional and cardiovascular outcomes in men and women with PAD, the Walking and Leg Circulation Study (WALCS). The blood factors under study which included fibrinogen, PAI-1, TPA antigen, d-dimer, prothrombin 1.2, and C-reactive protein (CRP), were associated with progression of coronary atherosclerosis in proposed models of the pathogenesis of coronary atherosclerosis, but were not well studied in PAD.

There were two specific aims. The first was to determine whether higher baseline blood factor levels were associated with a) progression of lower extremity arterial ischemia (decline in ankle brachial index >= 0.15, lower extremity gangrene, ulcer, revascularization, or amputation); b) functional decline over a 48 month follow-up. The second aim was to determine whether higher baseline blood factor levels were associated with new cardiovascular events over a 48 month follow-up. The hypothesis was that higher blood factor levels at baseline would be associated with PAD progression, functional decline, and higher rates of cardiovascular morbidity and mortality

Pilot data from the Cardiovascular Health Study (CHS) showed that relative risks of fibrinogen, D-dimer and CRP levels for cardiovascular events were highest for events occurring more proximate to baseline blood factor measurements. Therefore, the study also sought to determine whether blood factor levels measured at the most recent examination prior to cardiovascular events or PAD progression were higher than the levels that did not immediately precede cardiovascular events or PAD progression. The hypothesis was tested that blood factor levels at the most recent examination prior to cardiovascular events or PAD progression would be higher than blood factor levels that did not immediately precede cardiovascular events.

The study completion date listed in this record was obtained from the "End Date" entered in the Protocol Registration and Results System (PRS) record.

Study Type

Observational

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

No older than 100 years (Child, Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

No eligibility criteria

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Investigators

  • Mary McDermott, Northwestern University

Publications and helpful links

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General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

January 1, 2001

Study Completion (Actual)

December 1, 2005

Study Registration Dates

First Submitted

May 4, 2002

First Submitted That Met QC Criteria

May 4, 2002

First Posted (Estimate)

May 6, 2002

Study Record Updates

Last Update Posted (Estimate)

March 16, 2016

Last Update Submitted That Met QC Criteria

March 15, 2016

Last Verified

January 1, 2006

More Information

Terms related to this study

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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