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

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Abstract

Impaired coronary vasodilation to both endothelial-dependent and endothelial-independent stimuli have been associated with atherosclerosis. Direct measurement of coronary vasodilation using x-ray angiography or intravascular ultrasound is invasive and, thus, not appropriate for asymptomatic patients or for serial follow-up. In this study, high-resolution coronary cardiovascular magnetic resonance (CMR) was used to investigate the vasodilatory response to nitroglycerine (NTG) of asymptomatic patients at high risk for CAD.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.

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