PROGNOSTIC IMPORTANCE OF SCINTIGRAPHIC LEFT-VENTRICULAR CAVITY DILATION DURING INTRAVENOUS DIPYRIDAMOLE TC-99M SESTAMIBI MYOCARDIAL TOMOGRAPHIC IMAGING IN PREDICTING CORONARY EVENTS

Left ventricular (LV) cavity dilation during stress myocardial perfusi on imaging has been associated with multi-vessel disease, and may be a n independent prognostic marker in addition to perfusion defects. The present study examines the predictive value for future cardiac events of transient or fixed LV dilation during dipyridamole technetium-99m ( Tc-99m) sestamibi single-photon emission computed tomography (SPECT) i maging. The study included 512 consecutive patients who underwent SPEC T imaging with Tc-99m sestamibi after dipyridomole infusion. Transient LV dilation was seen in 70 patients (14%) and 74 had fixed cavity dil ation (14%); cavity size was normal in 368 patients (72%). Each perfus ion scan was classified as normal or abnormal, and if abnormal, defect s were categorized as transient or fixed, and as small, medium, or lar ge (depending upon the number of abnormal vascular territories). Event s during a mean follow-vp of 12.8 +/- 6.8 months were tabulated by dir ect review of hospital charts and death certificates. The cardiac even t rare (cardiac death or nonfatal infarction) was 1.9% in patients wit h normal cavity size, 11.4% with transient LV dilation, and 13.5% with fixed LV dilation (p < 0.01). Compared with patients with normal cavi ty size, those with transient LV dilation were more likely to sustain a myocardial infarction (p < 0.01) and those with fixed dilation more frequently suffered cardiac death (p < 0.01) and hospitalization for h eart failure (p < 0.01). The group with the highest risk had both a la rge perfusion defect and cavity dilation. By Cox proportional hazard r egression analysis, both transient and fixed LV dilation were strong i ndependent predictors of cardiac events. Transient or fixed LV dilatio n are commonly seen during dipyridamole Tc-99m sestamibi SPECT imaging (14% incidence for each) and are useful predictors of cardiac events. (C) 1997 by Excerpta Medica, Inc.