Radionuclide assessment of lower limb perfusion using 99mTc-MIBI in early stages of atherosclerosis.

BACKGROUND

The aim of the work was a scintigraphic evaluation of regional blood supply of thigh and calf muscles using 99mTc-MIBI as a radiopharmaceutical, in early stages of atherosclerosis revealed during ultrasonographic examination of lower limbs, in patients without typical clinical symptoms of chronic ischaemia of lower limbs and with preserved normal Doppler spectrum of blood flow. Moreover, basic relations between early signs of lower limb atherosclerosis and abnormal myocardial perfusion, as well as asymptomatic hypoperfusion of lower limbs, were analysed.

MATERIAL AND METHODS

Stress and rest radionuclide study of lower limb muscles and myocardium using 99mTc-MIBI was performed in 47 men, who were divided into two groups based on ultrasonography results. The first group (group I) comprised 22 patients with early atherosclerotic changes in peripheral vessels and the second (group II) comprised 25 people with normal arteries. For the purposes of quantification of study results normal values of regional blood supply and indices of asymmetry at levels of thighs and calves, as proposed by Segall et al., were applied. Myocardial scintigrams were evaluated according to widely accepted rules (visual and semi quantitative--normative analysis).

RESULTS

Mean values of stress and rest perfusion indices of thighs as well as calves in gr. I were statistically significantly lower (p < 0.001) than in gr. II. Incidence of asymmetry in the stress perfusion of calves and thighs was statistically significantly higher (p = 0.04) in patients with atherosclerotic changes as compared with the control group. Abnormal myocardial perfusion was found in 77% of patients from group I and in 28% from group II (p = 0.001). Reversible, stress induced ischaemia was found in 59% and 16%, resp. (p = 0.01).

CONCLUSIONS

1. Radionuclide study revealed a reduced stress as well as rest perfusion of lower limb muscles in clinically asymptomatic patients with atherosclerotic changes of lower limb vessels of low degree and a preserved normal Doppler blood flow spectrum. 2. Presence of early atherosclerotic changes in lower limb vessels implies a higher probability of asymptomatic hypoperfusion of lower limbs as well as coronary artery disease.