Quantitation of Left Ventricular Ejection Fraction Reserve from Early Gated Regadenoson Stress Tc-99m High Efficiency SPECT - The 63rd Annual Conference of the Israel Heart Society in association with the Israel Society of Cardiothoracic Surgery 12-13 April 2016, David Intercontinental Hotel, Tel-Aviv, Israel

Yafim Brodov ¹ Mathews Fish ² Heidi Gransar ¹ Daniel Berman ¹ Guido Germano ¹ Piotr Slomka ¹

¹Nuclear Cardiology and Cardiac Imaging, Cedars Sinai Medical Center, Los Angeles, California
²Nuclear Medicine Department, Oregon Heart and Vascular Institute, Sacred Heart Medical Center, Springfield, Oregon

Background: Ejection fraction (EF) reserve has been found as a useful adjunct for identifying high risk coronary artery disease in cardiac positron emission tomography. We aimed to evaluate EF reserve obtained from technetium-99m sestamibi (Tc-99m) high-efficiency (HE) SPECT.

Methods: Fifty patients (mean age 69 y) undergoing regadenoson same-day rest (9-11 mCi) / stress (37mCi) Tc-99m gated HE SPECT were enrolled. Stress imaging has been started one min after sequential intravenous regadenoson 0.4mg and Tc-99m injection, included five 2 min supine gated acquisitions followed by 4 min supine and upright images. Automated software with grouped processing was used to quantify EF for multiple scans. Significant ischemia was defined as ischemic total perfusion deficit (ITPD) ≥ 5 %.

Results: Significantly lower mean EF reserve was obtained in the 5^th and 9^th min after regadenoson bolus in patients with significant ischemia versus patients without (5^th min: -4.2 ± 4.6% vs. 1.3 ± 6.6%, respectively, p = 0.006; 9^th min: -2.7 ± 4.8% vs 2.0 ± 6.6%, respectively, p = 0.03).

Conclusions: Negative EF reserve obtained between 5^th and 9^th min of regadenoson stress demonstrated best concordance with significant ischemia and could be a promising tool for detection of myocardial stunning with Tc-99m HE-SPECT.