Abstract
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Objectives: The diagnostic accuracy of the CZT camera (DSPECT) for detection of obstructive coronary artery disease (CAD) has been reported to be similar between men and women. However, gender difference in the prevalence of obstructive CAD across the severity grade of perfusion abnormalities have not been examined.
Methods: DSPECT followed by invasive angiography was performed at 4 different centers in 924 patients with stress and rest scans available (65% men) without previously known CAD. Tc-99m sestamibi was injected, Images were acquired in supine and upright positions at rest and after vasodilator or exercise stress. Total perfusion defect (TPD) was quantified by QPS from upright and supine acquisition at stress and upright at rest. Ischemic TPD was defined as difference of stress and rest. Stress and Ischemic TPD were classified as TPD<3%, 3≤TPD<5, 5≤TPD<10, and 10≤TPD. Obstructive CAD was defined as presence of >70% stenosis. The prevalence of obstructive CAD across the TPD categories was compared between women and men. Results: In both women and men, the prevalence of obstructive CAD increased with progressively increasing stress and ischemic TPD (Figure). For stress TPD≥10% at supine and upright position, obstructive CAD was less common in women than in men (77% in women vs. 87% in men at supine, 75% in women vs. 84% in men at supine; P for both=0.03). However, obstructive CAD in women was as commonly observed as men for ischemic TPD≥10% (82% in women vs. 91% in men; P=0.06). Compared to men, the frequency of obstructive CAD was significantly lower in women for stress TPD at upright and ischemic TPD <3% (23% in women vs. 38% in men for stress TPD at upright; P=0.02, 24% in women vs. 43% in men for ischemic TPD; P =0.0005). Conclusion: We observed that there is a gender difference in prevalence of obstructive CAD across the same perfusion abnormality categories. This finding should be kept in mind to interpret MPI in DSPECT, especially with smaller TPD values.