Effect of sex, age, and weight on ejection fraction and end-systolic volume reference limits in gated myocardial perfusion SPECT.

Background: The left-ventricular ejection fraction (EF) and end-systolic volume (ESV) are strong predictors of prognosis for cardiac death. Gated myocardial perfusion single-photon emission computed tomography (gSPECT) may be used to measure ESV and EF. However, systematic differences may exist between referred populations. Our aim was to derive male and female reference limits for left-ventricular functional parameters, and determine the effect of age, weight, and body surface area (BSA).

Methods And Results: The ejection fraction and ESV were derived using QGS software for 127 patients with normal gSPECT studies. The lower reference limits of EF were 46.2% and 55.6% for men and women, respectively. The upper reference limits of ESV were 30.4 mL and 21.4 mL, and 15.7 mL/m(2) and 11.1 mL/m(2), when indexed to BSA for men and women, respectively. There was no correlation between EF and age, weight, or BSA (P > .05). There was a small decrease in ESV with age, and an increase with weight and BSA (P < .05). The sex-specific differences remained after adjusting for confounding variables.

Conclusions: We demonstrated a significant sex difference for all functional parameters measured, and we established the influence of patient age and weight. Local reference limits for ESV and EF have been established, and the latter are transferable to other departments operating similar protocols.