Noninvasive assessment of coronary vasodilation using cardiovascular magnetic resonance in patients at high risk for coronary artery disease

A total of 46 asymptomatic subjects were studied: 13 high-risk patients [8 with diabetes mellitus (DM), 5 with end stage renal disease (ESRD)] and 33 age-matched controls. Long-axis and cross-sectional coronary artery images were acquired pre- and 5 minutes post-sublingual NTG using a sub-mm-resolution multi-slice spiral coronary CMR sequence. Coronary cross sectional area (CSA) was measured on pre- and post-NTG images and % coronary vasodilation was calculated.Patients with DM and ESRD had impaired coronary vasodilation to NTG compared to age-matched controls (17.8 ± 7.3% vs. 25.6 ± 7.1%, p = 0.002). This remained significant for ESRD patients alone (14.8 ± 7.7% vs. 25.6 ± 7.1%; p = 0.003) and for DM patients alone (19.8 ± 6.3% vs. 25.6 ± 7.1%; p = 0.049), with a non-significant trend toward greater impairment in the ESRD vs. DM patients (14.8 ± 7.7% vs. 19.8 ± 6.3%; p = 0.23).Noninvasive coronary CMR demonstrates impairment of coronary vasodilation to NTG in high-risk patients with DM and ESRD. This may provide a functional indicator of subclinical atherosclerosis and warrants clinical follow up to determine prognostic significance.Impaired vasodilation is an early marker of atherosclerosis [1-4]. Although abnormal response to endothelial-dependent stimuli is more commonly associated with coronary artery disease (CAD) [3,5-8], several studies have associated impaired vasodilatory response to nitroglycerin (NTG) with risk factors for coronary artery disease [9] and increased future clinical events [6,10]. Previous studies, however, have used x ray angiography [3-8] and intravascular ultrasound [11] which are invasive and, thus, not appropriate for asymptomatic patients or serial follow-up. A non-invasive measure of subclinical coronary atherosclerosis may help identify patients who are at increased risk and guide therapy toward reducing morbidity and mortality. We and others have previously developed a non-invasive method to measure NTG-induced coronary vasodilatio