RecruitingACTRN12612000594820

Assessment of relationship between segmental coronary endothelial function and plaque progression/regression

The in vivo investigation of the relationship between segmental coronary endothelial function and atherosclerotic plaque progression/regression in patients with stable coronary artery disease.

Sponsor

Cardiovascular Investigation Unit, Royal Adelaide Hospital

Enrollment

45 participants

Start Date

Mar 4, 2013

Study Type

Observational

Conditions

Stable coronary artery disease patients

Summary

Vascular endothelium is known to have a pivotal role in the maintenance of vascular haemostasis including effects on vasomotor and platelet function, thrombus formation and fibrinolysis, cell growth and inflammation. Altered endothelial function (endothelial dysfunction), largely evaluated by vasodilator responses to endothelial dependent stimuli (ie. shear stress, acetylcholine, salbutamol), occurs in the setting of atherosclerosis and traditional cardiovascular risk factor. Furthermore, endothelial dysfunction measured in both the peripheral and coronary circulation, is associated with adverse risk of future cardiovascular events. The exact mechanism behind how endothelial function impacts on clinical events remains uncertain. We plan to embark on a set of experiments to assess the dynamic relationship between segmental coronary endothelial function and regional plaque progression or regression over time in patients with stable coronary artery disease. We are also interested to examine this relationship with the evolution of the lipid core content of an atheromatous plaque, a known marker of plaque vulnerability. Our patients will undergo a clinical follow up every 3 month until 18 months, when another endothelial function assessment will be performed to mark the end of the study. Although this is largely a mechanistic study, we believe that the result of this study will provide some initial data to provide a "gold standard" invasive assessment of vulnerable plaque, which in turn will aid in predicting individual future coronary event with more accuracy.

Eligibility

Sex: Both males and femalesMin Age: 18 Yearss

Plain Language Summary

Simplified for easier understanding

This study is using specialized imaging tools to look at the inner lining of the coronary arteries and measure how well they function over an 18-month period. Researchers want to understand the link between early artery dysfunction and whether plaque (fatty buildup) in the artery grows or shrinks over time. The knowledge gained could help identify which plaques are most dangerous and may eventually help predict who is at risk of a heart attack. You may be eligible if: - You are 18 years of age or older - You have a clinically-driven reason to have a coronary angiogram - Your coronary arteries show normal or non-critical disease (less than 30% narrowing) on imaging - For women: you must not be breastfeeding and must not be of childbearing potential You may NOT be eligible if: - You have moderate-to-severe heart failure or severely reduced heart pump function (ejection fraction below 35%) - You have uncontrolled high blood pressure (resting systolic above 180 mmHg) - You have severe valvular heart disease - You have a contraindication to coronary nitrate use (e.g., you take sildenafil, tadalafil, or vardenafil) - You have had a heart attack in the past 4 weeks - You have significant kidney disease, atrial fibrillation, or are an asthmatic Talk to your doctor about whether this trial might be right for you.

This summary was AI-generated to explain the trial in plain language. It is not medical advice. Always discuss eligibility with your doctor before enrolling in a clinical trial.

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Interventions

Patients who undergo elective coronary angiogram for a clinically driven indication and have an angiographic evidence of minor coronary artery disease will be included in our study. They will under

Patients who undergo elective coronary angiogram for a clinically driven indication and have an angiographic evidence of minor coronary artery disease will be included in our study. They will undergo coronary endothelial function assessment with intravascular ultrasound (with near infra-red spectroscopy capability) and intracoronary salbutamol and glyceryl trinitrate. The basis of invasive endothelial function is to visualise coronary artery response to a stimulus, such as salbutamol. An artery with normal endothelial function will dilate to such stimulus whilst failure to dilate or even constriction is an evidence of endothelial dysfunction. A combined intravascular ultrasound (IVUS) and near infra red spectroscopy (NIRS) catheter will be inserted via the same coronary angiogram access site to the coronary artery of interest. IVUS is excellent in visualizing the arterial wall including providing information regarding the extent of the plaque burden. Technological advances has allowed the incorporation of near infrared spectroscopy during image post processing to provide better identification of the lipid content of the plaque. Thus, we use this imaging modality to assess how the coronary artery behaves to various stimulus in a detailed fashion. The stimulus agents that we will be using are 0.3 microgram of salbutamol to assess the endothelial dependent response and 100 microgram of glyceryl trinitrate to assess the endothelial independent response as comparator. Each medication will be infused over 5 minutes. Salbutamol is an asthma medication which has been shown to cause coronary artery dilation in patients with normal endothelial function. Various literature has demonstrated its use as one of the vasomotor stimulus in endothelial function assessment. Glyceryl trinitrate, in contrast is a cardiac medication to relieve angina. It also causes dilation of coronary artery through a different mechanism to salbutamol. The procedure is estimated to take an extra 25 minutes on top of the duration of the angiogram. The patients will be clinically followed up on 3 monthly interval for a total of 18 months. A repeat endothelial function test will then be repeated to assess the state of health of the coronary artery during this study.

Locations(1)

Australia

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ACTRN12612000594820