Detection of Achilles Tendon Xanthoma in Patients with Phenotypical Familial Hypercholesterolemia: Physical Examination vs Sonography

Abstract

Introduction: Familial hypercholesterolaemia (FH) is a commonly underdiagnosed hereditary lipid disorder characterised by increased low density lipoprotein cholesterol (LDL-C). FH predisposes patients to premature cardiovascular disease (CVD). Achilles tendon (AT) xanthoma is pathognomonic of FH and can be detected via physical examination or ultrasound. Objectives: Evaluate the accuracy of ultrasound in AT xanthoma detection compared to physical examination in FH patients. Methods: Forty-two consecutive patients from MonashHEART lipid clinic with likely FH according to the Dutch Lipid Clinic Network Score were included in the study. On physical examination, patients were categorised as xanthoma (+) and xanthoma (−) based on tendon thickness and/or nodularity. On ultrasound, patients were categorised based on AT thickness or presence of hypoechogenic lesions within the tendon. Results: Eighty-four AT were investigated in total. Mean age 35.5 ± 14.7 years, mean LDL-C 5.5 ± 1.95 mmol/L and 47.6% were male. Premature CVD was present in 50% of the patients. The frequency of xanthoma was 73.8% by ultrasound and the median antero-posterior diameter was 5.15mm (IQR 4.7–5.7). Physical examination had sensitivity of 38% [95% confidence interval (CI) 24.7–52.8] and specificity of 73.5% [95% CI 55.6–87.1] in AT xanthoma detection. No statistically significant association between age and xanthoma was observed. Conclusion: This study suggests that ultrasound, used in conjunction with physical examination increases the accuracy of AT xanthoma detection in patients with likely FH.