Current Problems in Cardiology 07/2014; DOI:10.1016/j.cpcardiol.2014.05.002 · 2.17 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: The purpose of this study was to investigate whether endothelial dysfunction contributes to abnormal myocardial perfusion imaging (MPI) observed in patients without obstructive coronary artery disease (CAD). It is unclear whether reversible MPI defects detected in the absence of obstructive CAD represent underlying vascular pathology or are false-positive MPI results. Recent evidence suggests that coronary endothelial dysfunction might play a role in the pathogenesis of these defects.
We prospectively recruited 36 patients with chest discomfort, reversible abnormalities on MPI, and nonobstructive or absent CAD (stenosis <50% on coronary angiography). The control group (n = 55) consisted of patients with chest discomfort and similar cardiac risk factors but with normal MPI findings. Vascular endothelial function was assessed in the brachial artery by ultrasound as the response to hyperemia and reported as percent flow-mediated dilation (FMD). Response to sublingual nitroglycerin was used as an indicator of endothelium-independent vasodilation. The patients with abnormal MPI findings and nonobstructive CAD had a significantly lower FMD (9.0% +/- 7.2%), indicating endothelial dysfunction, compared with those with similar risk factors and normal MPI findings (12% +/- 5.2%) (P = .03). Baseline brachial artery size and endothelium-independent dilation were similar between groups. On multivariate analysis, only endothelial dysfunction was predictive of reversible MPI defects.
Patients with chest pain and reversible MPI defects but without obstructive CAD have lower FMD indicative of endothelial dysfunction, as compared with similar patients with normal MPI findings. The possibility of a causal link between reversible MPI defects and endothelial dysfunction needs further exploration.
Journal of Nuclear Cardiology 11/2006; 13(6):756-60. DOI:10.1016/j.nuclcard.2006.08.018 · 2.65 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: In this study, niacin was added to existing therapy for 3 months in 54 subjects with stable coronary artery disease. Average total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), and triglyceride levels were similar between groups. Three months of niacin treatment increased total HDL by 7.5% and decreased triglycerides by 15% compared with baseline values (p <0.005 for each), whereas total cholesterol and LDL levels remained unchanged. Addition of niacin resulted in a 32% increase in large-particle HDL (p <0.001), an 8% decrease in small-particle HDL (p = 0.0032), an 82% increase in large-particle LDL (p = 0.09), and a 12% decrease in small-particle LDL (p = 0.008). Niacin decreased lipoprotein-associated phospholipase A2 and C-reactive protein levels (20% and 15%, respectively, p <0.05 for the 2 comparisons). No significant changes from baseline were seen in any tested parameter in subjects who received placebo. In conclusion, addition of niacin to existing medical regimens for patients with coronary artery disease and already well-controlled LDL levels favorably improves the distribution of lipoprotein particle sizes and inflammatory markers in a manner that would be expected to confer atheroprotection. The effect of altering lipoprotein particle distribution and inflammatory markers on surrogate markers of atherosclerosis and clinical cardiovascular events in this population remains unclear.
The American Journal of Cardiology 09/2006; 98(6):743-5. DOI:10.1016/j.amjcard.2006.04.011 · 3.43 Impact Factor