Association Between Plasma Lipoprotein(a) and Endothelial Dysfunction in Normocholesterolemic and Non-Diabetic Patients With Angiographically Normal Coronary Arteries.

Abstract

ndothelial dysfunction, which can be proved by demonstrating loss of acetylcholine-induced vasodilation, is an early event of atherosclerosis in human coronary arteries 1,2 and seems to accelerate the progression of the atherosclerotic process. 3 In clinical studies, selective loss of endothelium-dependent vasodilation in response to acetylcholine (ACh) has been observed in not only angiographically atherosclerotic coronary arteries, but also in normal coronary arteries of hypercholesterolemic patients. 4,5 Lipoprotein(a) (Lp(a)) has been associated with ischemic heart disease and myocardial infarction in many epidemiological studies [6][7][8][9][10] and is now considered to be an independent risk factor for cardiovascular diseases. Lp(a) is a lowdensity lipoprotein (LDL) -like particle, so it could be atherogenic and impair endothelial function as does LDL. 11 Recently, Sorensen et al have reported that flow-mediated dilation in femoral artery is inversely related to the Lp(a) level in children with familial hypercholesterolemia, suggesting a contribution by Lp(a) to endothelial dysfunction. 12 A study by Tsurumi et al also revealed that Lp(a) correlated well with endothelial dysfunction in the human coronary artery as well as serum LDL cholesterol. 13 Moreover, patients with diabetes mellitus (DM) showed endothelial dysfunction that was probably caused by hyperglycemia Circulation Journal Vol.66, March 2002and hypertriglyceridemia. [14][15][16] To confirm whether or not Lp(a) has an independent role in endothelial dysfunction, we examined normocholesterolemic and non-diabetic patients with angiographically normal coronary arteries. Methods Study PatientsThe study group consisted of 31 patients (without any angiographically segmental stenoses or irregularities in the coronary arteries), who underwent diagnostic cardiac catheterization for chest pain or abnormal results of a noninvasive stress test. The patients with hypercholesterolemia (serum LDL cholesterol ≥160 mg/dl), hypertriglyceridemia (serum triglyceride ≥400 mg/dl), previous myocardial infarction, valvular heart disease, cardiomyopathies or DM (fasting plasma glucose ≥126 mg/dl) were excluded. Table 1 shows the profile of the patients: there were 14 male and 17 female patients, aged 59.4±9.2 years; 10 were smokers and 10 had a history of elevated blood pressure that resulted in the initiation of antihypertensive therapy by primary physicians. Patients had only been treated with calcium antagonists, not with angiotensin converting enzyme inhibitors or angiotensin II receptor blockers. Because only normocholesterolemic and non-diabetic patients were selected, none had taken any lipid-lowering drugs, including HMG-CoA reductase inhibitors, or anti-diabetic drugs. All women were post menopausal, the result of bilateral oophorocystectomy in one patient (no. 9 in Table 1) and aging in the others. None of the women were receiving estrogen therapy. None of the patients had a family history of early coronary artery disease. The institutional Ethics Committee ap...

Relationship Between Serum Lipoprotein(a) Concentrations and Coronary Vasomotion in Coronary Spastic Angina

“…[5][6][7] In the present study, serum Lp(a) concentrations were significantly higher in the lower dose EM group than in the full-dose EM group, which suggests that Lp(a) affects the basal tone in patients with CSA.…”

Relation Between Serum Lipoprotein (a) and Residual Lesion Stenosis of Coronary Artery After Myocardial Infarction Without Reperfusion Therapy

“…A possible reason for the absence of a relationship between the effect of thrombolytic therapy and serum Lp (a) levels in these reports, is that diabetes mellitus and hypercholesterolemia, which are more potent risk factors, may have masked the influence of Lp (a). Ioka, et al 21) examined the relation between serum Lp (a) levels and the endothelium-dependent vasoresponse to acetylcholine. They excluded patients with hypercholesterolemia and diabetes mellitus, and concluded that high Lp (a) levels might be a strong predictor of endothelial dysfunction in normocholesterolemic and non-DM patients.…”

Use of atropine in patients with recent myocardial infarction during exercise myocardial perfusion study

“…In healthy subjects, coronary infusion of acetylcholine produces coronary vasodilatation where as in patients with CAD, it reduces large coronary artery diameter and de-creases coronary flow velocity , [20]. This variation in response is attributed to altered endothelial reactivity on patients with CAD [21]. Atropine, an anticholinergic agent when administered to patients with CAD, is expected to increase the ischemic threshold during TMST.…”