Angiotensin Converting Enzyme (ACE) Inhibition and Peripheral Arterial Disease

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00681226
Recruitment Status : Completed
First Posted : May 21, 2008
Last Update Posted : April 5, 2012
Information provided by (Responsible Party):
Bayside Health

Brief Summary:
Leg pain caused by peripheral arterial disease (PAD) can severely impede walking ability. Our preliminary findings indicate that the drug ramipril is much more effective in improving walking ability than current therapies. To be accepted as a new treatment for PAD these findings require validation in a much larger clinical trial.We propose to examine the effects of ramipril therapy for 6 months in a randomized, controlled trial of patients with PAD. If positive, this study will identify ramipril as a potential new therapy for PAD.

Condition or disease Intervention/treatment Phase
Peripheral Arterial Disease Drug: Ramipril or matching placebo Phase 4

Detailed Description:

This proposal extends our novel finding that the angiotensin-converting enzyme (ACE) inhibitor, ramipril markedly improves walking ability in patients with peripheral arterial disease (PAD), by conducting a larger clinical trial including a broader cross-section of PAD patients.


That ramipril therapy for 24 weeks will result in clinically significant increases in both pain-free and maximum walking time and improve quality of life in patients with PAD.

Background Synopsis:

Peripheral arterial disease is a common disorder, with 12% of adults over 50 having an ankle-brachial index (ABI) diagnostic of PAD (<0.9). Approximately one third of these patients experience intermittent claudication during walking, limiting the ability of these older individuals to participate in normal activities. The aim of PAD treatment is to improve walking distance and quality of life in those with intermittent claudication, and to decrease long term cardiovascular morbidity and mortality. However, the range of medical treatments to improve walking distance in these patients is limited. Our pilot study demonstrates that treatment of PAD patients, with infra-inguinal disease and without diabetes with ramipril for 24 weeks, markedly improves waking ability. Relative to placebo, ramipril increased mean treadmill-assessed pain-free waking time by 227s (160%, p<0.001) and mean maximum walking time by 451s (240%, p<0.001). Assuming a constant speed of 0.89 m/s (3.2 km/hr), this corresponds to a clinically significant increase in walking distance of 401m (95% CI 330m to 480m) which would impact appreciably on daily functional capacity. The magnitude of this effect is significantly greater than that reported for conventional medical therapies and provides worthwhile clinical benefit.

Research Plan Synopsis:

The dramatic findings of our pilot study clearly warrant verification in a larger clinical trial including diabetic patients and those with aorto-iliac disease as well as infra-inguinal disease. The current proposal is to expand our pilot study into a large trial with broad inclusion criteria. We propose to include patients with diabetes mellitus not currently medicated with ACE inhibitors. 264 PAD patients will be randomised to either ramipril (10mg once daily) or matching placebo for 24 weeks in a randomised, double-blind placebo controlled trial. All patients will undergo a treadmill exercise test to determine pain free and maximum walking times, ABI measurements and Duplex scanning to determine stenosis severity, both at baseline and following 6 months of ramipril therapy. Functional capacity in a daily life setting, will be assessed using standardised questionnaires (Walking Impairment Questionnaire and Quality of Life Questionnaire).

Outcomes and Significance:

If positive this trial will validate our pilot findings that the ACE inhibitor ramipril is an efficacious new therapy for the treatment of patients with claudication resulting from PAD. Given the escalating prevalence of PAD, this work has the potential for widespread impact.

Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 200 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary Purpose: Treatment
Official Title: ACE Inhibition; A Potential New Therapy for Peripheral Arterial Disease
Study Start Date : January 2008
Actual Primary Completion Date : August 2011
Actual Study Completion Date : January 2012

Resource links provided by the National Library of Medicine

Drug Information available for: Ramipril

Intervention Details:
  • Drug: Ramipril or matching placebo
    10 mg Ramipril or matching placebo once daily for 6 months
    Other Name: Ramace

Primary Outcome Measures :
  1. walking time [ Time Frame: baseline and 6 months ]

Secondary Outcome Measures :
  1. walking impairment questionnaire [ Time Frame: baseline and 6 months ]

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

Ages Eligible for Study:   40 Years to 85 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Ankle brachial index of <0.9 in at least one leg
  • History of intermittent claudication (unilateral or bilateral)
  • A stable medication regimen for at least 6 months

Exclusion Criteria:

  • Limiting coronary artery disease
  • Renal failure (serum creatinine > 0.20 mmol/L)
  • Current treatment or treatment within the previous 6 months with ACE inhibitors or angiotensin II receptor antagonists

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00681226

Australia, Victoria
Baker Heart Research Institute
Melbourne, Victoria, Australia, 8008
Sponsors and Collaborators
Bayside Health
Principal Investigator: Bronwyn A Kingwell, PhD Baker Heart Research Institute

Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: Bayside Health Identifier: NCT00681226     History of Changes
Other Study ID Numbers: 273/06
First Posted: May 21, 2008    Key Record Dates
Last Update Posted: April 5, 2012
Last Verified: April 2012

Keywords provided by Bayside Health:
peripheral arterial disease
angiotensin converting enzyme inhibitors

Additional relevant MeSH terms:
Peripheral Arterial Disease
Peripheral Vascular Diseases
Arterial Occlusive Diseases
Vascular Diseases
Cardiovascular Diseases
Angiotensin-Converting Enzyme Inhibitors
Protease Inhibitors
Enzyme Inhibitors
Molecular Mechanisms of Pharmacological Action
Antihypertensive Agents