Assessment of Coronary Plaque Composition Using Optical Coherence Tomography

Assessment of Coronary Plaque Composition Using Optical Coherence Tomography During Chronic Inhibition of Lipoprotein-associated Phospholipase A2 (Lp-PLA2) Activity

The investigator's hypothesis is that local activation of the endogenous Lp-PLA2 plays an integral role in early atherosclerosis, and contributes to the mechanism of coronary endothelial dysfunction and to the structural and mechanical properties that characterize plaque vulnerability. Thus, the investigators study will characterize prospectively the correlation between the functional and structural vascular wall properties, and the activity of the Lp-PLA2 pathway.

The present study was a substudy of our National Institute of Health (NIH) funded and Institutional Review Board (IRB) approved (08-008161) protocol "Lp-PLA2 and Coronary Atherosclerosis in Humans" and (10-000044) "Lp-PLA2 and Coronary Atherosclerosis in Humans Aim III" in which the investigators are examining the impact of long-term inhibition of Lp-PLA2, with a specific novel inhibitor, on Lp-PLA2 activity and improvement in coronary endothelial function. This substudy will use Optical Coherence Tomography (OCT) to quantify alternate features of plaque vulnerability including superficial microcalcification, fibrous cap thickness, and plaque macrophage content at baseline and again at 6 months following Lp-PLA2 inhibition. The study will provide insight into the role of the endogenous Lp-PLA2 in early coronary atherosclerosis, a potential therapeutic target for early coronary atherosclerosis in humans.

Subjects enrolled in the NIH funded and IRB approved (08-008161) protocol "Lp-PLA2 and Coronary Atherosclerosis in Humans" with a positive diagnosis of coronary artery endothelial dysfunction will be studied using Optical Coherence Tomography during the angiogram at baseline.

Subjects who are enrolled in IRB 10-000044 "Lp-PLA2 and Coronary Atherosclerosis in Humans Aim III" a study in which the investigators are examining the impact of long-term inhibition of Lp-PLA2, with a specific novel inhibitor or placebo, on Lp-PLA2 activity and improvement in coronary endothelial function will be studied using Optical Coherence Tomography during the 6 month return angiogram.

Evaluation of the coronary artery using Optical Coherence Tomography utilizing the Dragonfly OCT catheter following a clinically indicated angiogram and endothelial function testing with a positive diagnosis of endothelial dysfunction. The procedure is repeated following 6 months of Lp-PLa2 inhibition or placebo.

Following recruitment of the total study population and 6-months therapy with the Lp-PLA2 inhibitor or placebo, using Optical Coherence Tomography (OCT) we will quantify alternate features of plaque vulnerability including superficial microcalcification, fibrous cap thickness, and plaque macrophage content comparing baseline and 6 months studies.

Inclusion Criteria: age > 18 years and < 85 years referred to our cardiac catheterization laboratory for coronary vasomotion testing are found to have coronary endothelial dysfunction. Exclusion Criteria: these include heart failure ejection fraction < 40% unstable angina myocardial infarction or angioplasty within 6 months prior to entry into the study use of investigational agents within 1 month of entry into the study, patients who require treatment with positive inotropic agents other than digoxin during the study patients with cerebrovascular accident within 6 months prior to entry the study significant endocrine, hepatic or renal, disorders local or systemic infectious disease within 4 weeks prior to entry into study pregnancy or lactation mental instability Federal Medical Center inmates