The role of left ventricular hypertrophy and diabetes in the presence of transient ischemic dilation of the left ventricle on myocardial perfusion SPECT images.
Transient ischemic dilation of the left ventricle found on SPECT myocardial perfusion imaging (MPI) is an accepted marker of severe and extensive coronary artery disease (CAD) and poor prognosis. The influence of other clinical variables on the incidence of transient ischemic dilation is less certain. The aim of this study was to investigate clinical factors that may influence the incidence of transient ischemic dilation. In particular, we looked at factors that may independently affect subendocardial perfusion, such as left ventricular hypertrophy (LVH) and diabetes.


METHODS
MPI studies of 103 consecutive patients who had undergone recent coronary angiography (< or =6 mo) and transthoracic echocardiography within a year of stress electrocardiography-gated MPI were retrospectively analyzed. Transient ischemic dilation was assessed quantitatively using a software program. A ratio cutoff of > or =1.22 was considered to represent transient ischemic dilation. Summed stress score and summed difference score (ischemia score) were determined using the standard 17-segment 5-point scoring system to quantify myocardial ischemia. LVH was defined as a left ventricular wall thickness of >11 mm on M-mode echocardiography. Severe CAD was defined as severe stenosis (> or =90%) of either the left anterior descending artery or both the right coronary and lateral circumflex arteries.


RESULTS
Nineteen (18%) of the 103 patients had transient ischemic dilation, 19 (18%) had LVH, and 23 (22%) were diabetic. A high percentage had severe CAD (46/103 [45%]), whereas 57 of 103 (55%) had less severe CAD (30/103 [29%]) or nonsignificant CAD (26/103 [25%]). Severe CAD (P < 0.001), diabetes (P < 0.0001), LVH (P < 0.003), and the ischemia score (P < 0.023) were independent predictors of transient ischemic dilation by multivariate logistic regression. In patients with severe CAD, the effect of LVH on the incidence of transient ischemic dilation was additive, increasing the incidence from 21% (8/38) without LVH to 75% (6/8) with LVH (P < 0.006). Likewise, with severe CAD, the incidence of transient ischemic dilation rose from 21% (7/33) in patients without diabetes to 54% (7/13) in those with diabetes (P < 0.04).


CONCLUSIONS
The presence of transient ischemic dilation on myocardial perfusion SPECT is associated with the presence of severe CAD, but this association is modified by the presence of LVH and diabetes.
Emmett
Louise
L
Department of Nuclear Medicine, Concord Hospital, University of Sydney, Sydney, Australia. louisee@nucmed.crg.cs.nsw.gov.au
Magee
Michael
M
Freedman
S Ben
SB
Van der Wall
Hans
H
Bush
Vivienne
V
Trieu
Joseph
J
Van Gaal
William
W
Allman
Kevin C
KC
Kritharides
Leonard
L
D000368:Aged; D001315:Australia / Q000453:epidemiology; D015897:Comorbidity; D003920:Diabetes Mellitus / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D005260:Female; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D008297:Male; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D015995:Prevalence; D011379:Prognosis; D015203:Reproducibility of Results; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013997:Time Factors; D015899:Tomography, Emission-Computed, Single-Photon / Q000706:statistics & numerical data; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000453:epidemiology*