Value of vasodilator left ventricular ejection fraction reserve in evaluating the magnitude of myocardium at risk and the extent of angiographic coronary artery disease: a 82Rb PET/CT study.

UNLABELLED Our aim was to determine the value of vasodilator left ventricular ejection fraction (LVEF) reserve (stress ejection fraction - rest ejection fraction) in evaluating the magnitude of myocardium at risk and the anatomic extent of underlying severe coronary artery disease (CAD). METHODS We studied 510 consecutive patients with suspected CAD undergoing gated rest and vasodilator stress (82)Rb PET/CT. Patients were categorized as having no perfusion abnormalities, mild, moderate, or severe reversible perfusion defects. In a subgroup of 68 patients with coronary angiography, patients were categorized as having 0-vessel, 1-vessel, 2-vessel, or left main/3-vessel disease. RESULTS Patients without coronary risk factors who comprised our control group as well as patients with coronary risk factors and normal perfusion demonstrated a high LVEF reserve (7% +/- 7% and 5% +/- 6%, respectively). The mean LVEF reserve was negative (-0.2% +/- 8%) in patients with severe reversible defects and in patients with 3-vessel (-6% +/- 8%) and left main (-8% +/- 5%) disease. Among the clinical and scintigraphic variables studied, male sex, rest ejection fraction, and increasing magnitude of myocardium at risk predicted a lower LVEF reserve, whereas LVEF reserve was the only independent predictor of left main/3-vessel disease (P = 0.008). An LVEF reserve of more than +5% had a positive predictive value of only 41% but a negative predictive value of 97% for excluding severe left main/3-vessel CAD. CONCLUSION During (82)Rb PET/CT, LVEF increases with vasodilator stress in patients without significant stress-induced perfusion defects or severe left main/3-vessel CAD. A high LVEF reserve appears to be an excellent tool to exclude left main/3-vessel CAD noninvasively.