l -Arginine Normalizes Coronary Vasomotion in Long-Term Smokers

Abstract

Background-Noninvasive measurements of myocardial blood flow (MBF) with PET revealed an abnormal coronary vasomotor response to cold pressor test in healthy long-term smokers. If coronary endothelial dysfunction accounted for this abnormality, we hypothesized that it could be reversed by L-arginine as the substrate for NO synthase. Methods and Results-MBF was quantified with

Noninvasive Assessment of Coronary Microcirculatory Function in Postmenopausal Women and Effects of Short-Term and Long-Term Estrogen Administration

“…5,9 -11 The MBF response may, however, be diminished in CAD, in mildly diseased coronary arteries, or if the efferent adrenergic system is impaired. 5,9,10 Coronary risk factors have also been shown to attenuate the MBF response, 5,11 probably because of endothelial dysfunction. These RFs, in addition to estrogen withdrawal, accounted for the abnormal MBF response.…”

“…MBF was measured with intravenous 13 N-ammonia, serial image acquisition with PET (ECAT EXACT HRϩ, CTI-Siemens) and a 2-compartment tracer kinetic model as described previously. 5,6 The relative myocardial perfusion was assessed visually on reoriented static 13 N-ammonia images and by quantitative polar map analysis. 5…”

“…5,6 Such measurements allow an assessment of the coronary microcirculatory vasomotor control. Flow responses to stimulation with the vascular smooth muscle dilator dipyridamole provide information on the predominantly vascular smooth muscle control and the integrated function of the coronary circulation.…”

“…7 Adrenergically mediated flow responses to cold pressor testing (CPT) reflect the predominantly endothelialdependent vasomotion, as demonstrated with invasive coronary flow measurements after intracoronary acetylcholine 8,9 and, more recently, with noninvasive PET measured MBFs. 5,10,11 The purpose of this study was to examine with PET the effects of short-term and long-term estrogen administration on coronary vasomotion in postmenopausal women with and without coronary risk factors (RFs) but without CAD and compare the responses with those in healthy young reproductive-aged women.…”

Risk Evaluation for Coronary Artery Disease in Patients With Impaired Glucose Tolerance After a Successful Coronary Intervention

“…Investigating the vascular response to a cold pressor test (CPT) in combination with imaging modalities is an established method for evaluating endothelial function [7,8]. In particular, positron emission tomography (PET) using N-13 ammonia allows quantitative measurements of myocardial blood flow (MBF) [9,10], which have been used to evaluate endothelial function as a %increase in MBF from rest to the CPT-induced stress condition [8,11,12].…”