A hypertensive response to exercise is associated with transient ischemic dilation on myocardial perfusion SPECT imaging.
BACKGROUND
A hypertensive response to exercise (HRE) is associated with false-positive stress echocardiograms and myocardial perfusion single photon emission computed tomography (myocardial perfusion imaging [MPI]) defects even in the absence of coronary artery disease (CAD). Transient ischemic dilation (TID) of the left ventricle on stress MPI is a marker of severe CAD and future cardiac events. This study evaluated the association between an HRE and TID.


RESULTS
Blinded quantitative TID assessment was performed in 125 patients who had an HRE and a summed stress score (SSS) of less than 4, as well as 125 control patients with an SSS of less than 4 and without an HRE matched for age, gender, and resting systolic blood pressure. Cardiac comorbidities, pretest Framingham risk, and exercise results were recorded. TID was defined as a stress-to-rest volume ratio of 1.22 or greater. An HRE was associated with a high prevalence of TID and significantly more TID than no HRE (25.6% vs 11.2%; odds ratio, 3.00 [95% confidence interval, 1.41-6.38]). TID was more prevalent even in subgroups with a low pretest probability CAD, including those without diabetes mellitus or angina. On conditional logistic regression analysis, an HRE was found to be independently associated with TID after consideration of other clinical and exercise MPI variables (odds ratio, 2.72 [95% confidence interval, 1.01-7.31]).


CONCLUSIONS
An HRE is associated with a high prevalence of TID in patients without other significant perfusion defects, possibly as a result of global subendocardial ischemia induced by the HRE.
Smelley
Matthew P
MP
Section of Cardiology, Department of Medicine, University of Chicago, Chicago, Ill, USA.
Virnich
Daniel E
DE
Williams
Kim A
KA
Ward
R Parker
RP
D000368:Aged; D001794:Blood Pressure; D015444:Exercise; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D006973:Hypertension / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000473:pathology*; D009206:Myocardium / Q000473:pathology; D010477:Perfusion; D012306:Risk; D013997:Time Factors; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*