Ultrasonography of achilles tendons in primary hypercholesterolemia. Comparison with computed tomography

Tendon xanthoma are a hallmark of familial hypercholesterolemia and are among its earliest clinical manifestations. Achilles tendon size, advanced to a generally accepted marker, is virtually specific for the disease and easily accessible for measurement. Hypercholesterolemic patients with coronary heart disease have been reported to have larger diameters of the Achilles tendons than patients without coronary problems. Furthermore, Achilles tendon xanthomas have been shown to regress with treatment of the lipid disorder. Mainly radiological procedures were applied in the past to evaluate the diameters of the Achilles tendon but their use is limited by radiation protection. We have used real-time ultrasonography to evaluate the Achilles tendons of 38 patients with primary hypercholesterolemia and 32 normocholesterolemic controls. The anterior posterior diameter in the patients was 13.4 +/- 5.9 mm (range 6-20 mm) and 5.7 +/- 0.7 mm (range 5-8 mm) in the control group. In 8 patients with newly diagnosed and previously untreated hypercholesterolemia the thickness correlated highly with their age. The Achilles tendons in about half of the patients (n = 21) showed a homogeneous thickening, whereas the others revealed an inhomogeneous thickening indicating the presence of circumscribed xanthoma. Upon comparison of the ultrasonographic procedure with an established method (computed tomography) in 18 patients and 8 normal volunteers a highly significant correlation (r = 0.96) proved the validity of the sonography. We show that real time ultrasonography is a valid procedure to assess Achilles tendon diameters in patients with primary hypercholesterolemia. It can be applied frequently and may be useful to follow xanthoma regression during lipid lowering treatment.