Vasodilator stress impairs the left ventricular function obtained with gated single-photon emission computed tomography in patients with known or suspected coronary artery disease.
BACKGROUND
Transient ischemic dilatation (TID) and post-stress dysfunction of the left ventricle (LV) are important markers of severe coronary artery disease (CAD). To clarify the effects of stressor type on TID and post-stress LV dysfunction, changes in LV measurements were compared between patients with exercise- or vasodilator-induced stress.


RESULTS
The 689 patients referred for technetium-99m tetrofosmin myocardial perfusion imaging were included. Patients were stressed with either a vasodilator (n=236) or exercise (n=453). LV measurements were obtained with ECG-gated SPECT. LV end-diastolic and end-systolic volume indexes (LVEDVI, LVESVI) increased and LV ejection fraction (LVEF) decreased after stress in the vasodilator-stress group. Vasodilator-stress and the summed difference score (SDS) were independent variables that decreased LVEF after stress. Even in patients without reversible defects, vasodilator-stress impaired LV function. There were no differences in the stress-to-rest ratios of LVEDVI (rEDV) and LVESVI (rESV) among patients with normal myocardial perfusion, fixed defects and reversible defects in the vasodilator-stress group, whereas in the exercise-stress group, rESV was significantly higher in the patients with reversible defects than in those without reversible defects. Within the vasodilator-stress group, neither rEDV nor rESV correlated with the SDS.


CONCLUSIONS
Vasodilator-stress by itself decreases LVEF after stress. TID should be carefully interpreted when vasodilator-stress is used to detect severe CAD.
Division of Cardiology, Internal Medicine III, Hamamatsu University School of Medicine, Hamamatsu, Japan. k-altair@nifty.com
Keiichi
K
Odagiri
Masashi
M
Machii
Takamitsu
T
Tanaka
Akihiko
A
Uehara
Chinori
C
Kurata
Harumi
H
Sakahara
Yasuo
Y
Takehara
Masao
M
Saotome
Tsuyoshi
T
Urushida
Hideki
H
Katoh
Hiroshi
H
Satoh
Hideharu
H
Hayashi
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012189:Retrospective Studies; D015899:Tomography, Emission-Computed, Single-Photon; D014665:Vasodilator Agents / Q000008:administration & dosage*; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging; D016277:Ventricular Function, Left
D014665:Vasodilator Agents