No abstract

Intraprocedural contrast-enhanced rotational angiography provides volumetric 3-D images of the LA-PVs of comparable diagnostic value to dedicated preprocedural CT/MR imaging.

Background-In the presence of atherosclerosis, the coronary endothelial vasomotor response to acetylcholine is frequently abnormal but is variable between patients. We tested the hypothesis that the plasma concentration of ␣-tocopherol is associated with the preservation of nitric oxide-mediated endothelium-dependent vasomotion. Methods and Results-We studied 15 men and 6 women (mean age 61Ϯ10 years) at coronary angiography who were not taking vitamin supplements. Coronary endothelium-dependent and -independent vasomotion was assessed by intracoronary infusions of acetylcholine and nitroglycerin. The vasomotor responses were compared with the plasma concentration of ␣-tocopherol and the plasma ␣-tocopherol concentration relative to total lipid (total cholesterol plus triglycerides). The mean plasma ␣-tocopherol was 25.6Ϯ6.1 mol/L, total cholesterol 193Ϯ27 mg/dL, triglycerides 115Ϯ66 mg/dL, and ␣-tocopherol to total lipid 4.2Ϯ0.9 mol ⅐ L Ϫ1 ⅐ (mmol/L) Ϫ1. The mean vasomotor response to acetylcholine was Ϫ1% (range Ϫ33% to 28%) and to nitroglycerin 22% (range 0% to 54%). Plasma ␣-tocopherol was significantly correlated with the acetylcholine response (rϭ0.49, PϽ0.05) but not the nitroglycerin response (rϭ0.13, PϾ0.05). The acetylcholine response remained significant after adjustment for other potential sources of oxidant stress (total cholesterol, diabetes mellitus, smoking, angina class) (PϽ0.01). The relative concentration of ␣-tocopherol to total lipid was not related to endothelial function (rϭ0.24, Pϭ0.3, nϭ20). Conclusions-␣-Tocopherol may preserve endothelial vasomotor function in patients with coronary atherosclerosis. This effect may be related primarily to the action of ␣-tocopherol in the vascular wall. Further studies that assess the impact of ␣-tocopherol supplementation as therapy of endothelial dysfunction are justified. (Circulation. 1999;100:219-221.)Key Words: endothelium Ⅲ antioxidants Ⅲ atherosclerosis N itric oxide plays an essential role in the regulation of arterial tone. 1 Nitric oxide also inhibits local inflammation, coagulation, and cell proliferation. 1 Loss of nitric oxide impairs these protective mechanisms throughout the development of atherosclerosis.Evidence is accumulating that oxidant stress contributes to endothelial dysfunction in coronary atherosclerosis by enhancing the degradation and inhibiting the synthesis of nitric oxide. 1,2 Antioxidants can restore endothelium-mediated vasodilator function in patients with atherosclerosis or with coronary risk factors. [3][4][5][6] In the presence of coronary atherosclerosis or its risk factors, coronary endothelial vasomotor function is abnormal on average but is variable from patient to patient when assessed with acetylcholine or other stimuli. 7,8 Endogenous mechanisms may preserve the availability of nitric oxide in some patients.␣-Tocopherol is a potent lipid-soluble antioxidant and the most abundant isomer of vitamin E found in humans. 9 It circulates in plasma within LDL particles and is also taken up by arterial wall cells. We ...