The consequences of a new software package for the quantification of gated-SPECT myocardial perfusion studies
BACKGROUND The aim of this study was to assess whether adenosine impairs left ventricular ejection fraction (LVEF) obtained with gated SPECT in patients with a normal myocardial perfusion scintigram. MATERIALS AND METHODS This prospective study included 160 consecutive patients with a normal myocardial perfusion scintigraphy (MPS), who were stressed with either exercise (n = 64) or with adenosine (n = 96). Student t-test or chi test was used to compare patient's characteristics and functional parameters. Linear regression analyses were used to assess which patient characteristics had an independent significant influence on LVEF. RESULTS Functional parameters at rest were not significantly different between the adenosine group and the exercise stress group. However at stress, these functional parameters were significantly different. LVEF in the adenosine group decreased by -2.5%, whereas in the exercise group LVEF increased by 2.2% (P = 0.001). Moreover, in 36.5% of the patients a decrease in the LVEF of more than 5% was observed in the group stressed with adenosine compared with 15.6% in the exercise group (P = 0.002). In regression analysis, adenosine (P = 0.001) was selected as an independent significant correlate of a decrease in LVEF. CONCLUSION Adenosine seems to impair the LVEF obtained with gated SPECT in patients with a normal perfusion scintigram. Further evaluation is necessary to elucidate how adenosine exerts this effect and also, whether this finding has a prognostic value in patients with a normal perfusion scintigram.