Patients with systemic lupus erythematosus (SLE) may develop premature atherosclerosis, notably peripheral vascular disease (PVD) presenting with intermittent claudication or gangrene. Therefore, it is important to investigate if high prevalence of poor muscle perfusion of lower extremities in SLE patients with abnormal myocardial perfusion is related to more cardiovascular risk factors. We used a well-established and noninvasive radionuclide method (xenon 133 muscle washout) to evaluate objectively the anterior tibial muscle perfusion of 34 SLE female patients without symptoms/signs of PVD in the lower extremities. The patients were separated into two groups according to myocardial perfusion imaging results. Meanwhile, 30 normal female controls with matched age distribution were also included for comparison. The muscle perfusion differed significantly ( P <0.05) between patients (1.90+/-0.41 ml/100 g per min) and controls (2.91+/-0.50 ml/100 g per min), as well as between 18 SLE patients with abnormal myocardial perfusion (1.33+/-0.43 ml/100 g per min) and 16 with normal myocardial perfusion (2.26+/-0.45 ml/100 g per min). Based on the xenon 133 muscle washout method, we conclude that muscle perfusion in the lower extremities of SLE patients without symptoms/signs of PVD is significantly decreased and related to abnormal myocardial perfusion.