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.