Fatores biológicos e superestimação da fração de ejeção do ventrículo esquerdo no gated SPECT

Abstract

Some patients present an overestimated left ventricular ejection fraction (LVEF) on electrocardiogram-gated myocardial scintigraphy (gated SPECT). To establish the relationship between biological factors and overestimated LVEF. We selected 3838 patients who underwent gated SPECT between May 20, 2000 and September 16, 2005 with normal perfusion images and LVEF > or =50%. The following variables were analyzed: gender (29.4% females and 70.6% males), age (from 20 to 94 years - mean: 56 years), weight (from 33.5 to 150 kg - mean: 79.6 kg), height (from 138 to 220 cm - mean: 171 cm) and BMI (from 13.9 to 54 - mean: 27.2). In a subgroup of 1002 patients who underwent echocardiogram, the diastolic diameter (from 36 to 68 mm - mean 47.5 mm) and systolic diameter (from 22 to 41 mm - mean 29.8 mm) variables were included. The patients were divided into two groups: normal LVEF (< or =80%) and overestimated LVEF (>80%). The odds ratio (OR) for presenting an overestimated LVEF was calculated for each variable using logistic regression. The following odds ratios were found (p < 0.005): female gender OR = 3.585 (95%CI: 2.745 to 4.683), age in years OR = 1.020 (95%CI: 1.011 to 1.029) and height in cm OR = 0.893 (95%CI: 0.829 to 0.962). Weight and BMI were not significantly associated with LVEF (p>0.2). In the subgroup of 1002 patients, a statistically significant influence was found in overestimated LVEF values for the systolic diameter, gender and height variables. Although systolic diameter influences the overestimation of LVEF, the gender and height variables have an independent influence on LVEF overestimation by gated SPECT.