Evaluation and comparison of prognostic value of transient ischemic dilation after correction based on the other volumetric parameters of left ventricle

Background: For the interpretation of myocardial perfusion imaging (MPI), considering non-perfusion variables, such as transient ischemic dilatation (TID), are also important in diagnostic and prognostic evaluation of a patient. TID has a relatively high false positive and false negative results, which reduces its diagnostic and prognostic values. In this study, we aimed to increase the accuracy of TID by normalization of TID according to changes in other parts of LV which mostly occurred due to non-ischemic factors.Methods and Results: Patients referred to the nuclear medicine departments for dipyridamole MPI SPECT, one to two year prior to the study with TID ratio > 1 were enrolled. Patients with any previous history of revascularization and structural heart disease were excluded. Follow-up was done by phone call. The occurrence of cardiac death, myocardial infarction, revascularization or evidence of abnormal angiography during one year after MPI was considered positive for short-term cardiac events. The corrected TID (cTID) was calculated by the following formula: cTID = TID/(Wallstress/Wallrest). Among 196 participants, 30 (15%) had cardiovascular events during the follow-up. The area under the receiver operating characteristic (ROC) curve for the short-term prognosis of the cardiac events were 0.57 and 0.50 for cTID and TID with a p-value of 0.17 and 0.92, respectively. Considering the best cut-off points that were achieved by ROC curves, cTID showed significant odds ratio (OR:2.53) for prediction of short-term cardiac events, while in this regard, TID failed to be statistically significant.Conclusion: Making correction on TID using LV wall volumes can improve short-term prognostic value of this variable. However, further investigations and validations are required.

کلیدواژه ها:

SPECT MPI ، Transient Ischemic Dilatation ، prognosis