Attenuated myocardial vasodilator response in patients with hypertensive hypertrophy revealed by oxygenation-dependent magnetic resonance imaging.
BACKGROUND
Oxygen (O(2)) homeostasis is central to myocardial tissue functioning, and increased O(2) demand is thought to be satisfied by a vasodilatory mechanism that results in increased blood and O(2) delivery. We applied blood oxygenation level-dependent (BOLD) MRI in conjunction with vasodilatory stress to index the ability to augment intramyocardial oxygenation in hypertensive hypertrophy, the primary cause of heart failure.


RESULTS
Nine healthy controls and 10 hypertensive subjects with moderate-to-severe hypertrophy underwent imaging on a 1.5 T clinical scanner. The dipyridamole-induced change in the apparent transverse relaxation rate, R2*, which correlates with hemoglobin oxygenation, was -5.4+/-2.2 s(-1) (95% CI, -4.0 to -6.8 s(-1)) in controls compared with -1.7+/-1.4 s(-1) (95% CI, -0.8 to -2.6 s(-1)) in hypertensive patients (P=0.0003).


CONCLUSIONS
Patients with hypertensive hypertrophy demonstrate an impaired ability to increase intramyocardial oxygenation during vasodilatory stress, as indexed by BOLD MRI. The capacity to image vascular function with BOLD MRI may advance the understanding of the development of ventricular dysfunction in hypertension.
Beache
G M
GM
Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA. gbeache@umm.edu
Herzka
D A
DA
Boxerman
J L
JL
Post
W S
WS
Gupta
S N
SN
Faranesh
A Z
AZ
Solaiyappan
M
M
Bottomley
P A
PA
Weiss
J L
JL
Shapiro
E P
EP
Hill
M N
MN
D000328:Adult; D003326:Coronary Circulation / Q000187:drug effects; D003331:Coronary Vessels / Q000187:drug effects / Q000503:physiopathology; D004176:Dipyridamole / Q000008:administration & dosage; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000150:complications / Q000503:physiopathology*; D017379:Hypertrophy, Left Ventricular / Q000097:blood / Q000209:etiology / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood*; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000008:administration & dosage
D014665:Vasodilator Agents; D004176:Dipyridamole; D010100:Oxygen