Impaired coronary vasodilation by magnetic resonance angiography is associated with advanced coronary artery calcification.
OBJECTIVE
This study evaluated the hypothesis that impaired nitroglycerin (NTG)-induced coronary vasodilation is associated with advanced coronary atherosclerosis in asymptomatic older patients.


BACKGROUND
Atherosclerosis is associated with both structural and functional abnormalities of the vessel wall. Noninvasive functional measures of subclinical coronary atherosclerosis may help characterize high-risk subjects and guide preventive therapy.


METHODS
A total of 236 older patients (age 60 to 72 years, 33% female) without a history of cardiovascular disease were studied. Nitroglycerin-induced coronary vasodilation was measured by magnetic resonance angiography (MRA). Cross-sectional images of the right coronary artery were acquired before and 5 min after 0.4-mg sublingual NTG using a gated, breath-held spiral coronary MRA sequence (0.7-mm resolution). Quantitative analysis of the increase in cross-sectional area was performed in the 90% of patients (n = 212) with adequate image quality. Quantitation of coronary artery calcification (CAC) was performed by multidetector computed tomography using the Agatston method.


RESULTS
Forty patients (19%) had advanced CAC (> or =400). Coronary vasodilation to NTG was significantly impaired (p = 0.02) in patients with advanced CAC (median [interquartile range] = 15.9% [4.2% to 28.0%] vs. 21.5% [9.6% to 36.6%] for CAC <400). Importantly, NTG-induced coronary vasodilation remained independently associated with advanced CAC after multivariate analysis incorporating risk factors (p = 0.02) and other potential confounders (p = 0.04). There was no significant difference in coronary vasodilation between men and women, but few women (n = 3) had advanced CAC.


CONCLUSIONS
Impaired NTG-induced coronary vasodilation by MRA is associated with advanced coronary atherosclerosis in a community-based cohort of older asymptomatic subjects. Coronary MRA may provide a noninvasive functional assessment of subclinical coronary atherosclerosis.
Stanford University School of Medicine, California, USA.
Masahiro
M
Terashima
Patricia K
PK
Nguyen
Geoffrey D
GD
Rubin
Carlos
C
Iribarren
Brian K
BK
Courtney
Alan S
AS
Go
Stephen P
SP
Fortmann
Michael V
MV
McConnell
D000368:Aged; D002114:Calcinosis / Q000175:diagnosis* / Q000503:physiopathology; D003324:Coronary Artery Disease / Q000175:diagnosis* / Q000503:physiopathology; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D005996:Nitroglycerin; D011237:Predictive Value of Tests; D012720:Severity of Illness Index; D014664:Vasodilation; D014665:Vasodilator Agents
D014665:Vasodilator Agents; D005996:Nitroglycerin