Diagnostic accuracy of ultrasound and MRI for Achilles tendon xanthoma in people with familial hypercholesterolemia: A systematic review.

BACKGROUND: Achilles tendon xanthoma (ATX) results from tendon thickening and subclinical inflammation triggered by hypercholesterolemia, and is associated with more severe coronary artery disease and a higher risk of cardiovascular events. The ability to detect ATX by clinical examination is limited, and diagnostic imaging, for instance, using ultrasonography or magnetic resonance imagine (MRI), may improve the identification of ATX. However, the accuracy of ultrasound (US) imaging or MRI in identifying ATX in people with familial hypercholesterolemia (FH) has not been systematically reviewed.

OBJECTIVE: The objective of this study was to systematically review the accuracy of US imaging or MRI in diagnosing ATX in individuals with FH.

METHODS: Searches in Medline, Embase, Cochrane Central, and Cochrane Database of Systematic Reviews on the Ovid platform from inception to April 15, 2018, were conducted to identify articles. Any study design that included US imaging or MRI of Achilles tendon xanthoma in people with FH, and that included a control group of non-FH participants with either normal or symptomatic Achilles tendons, was considered eligible. All of the included studies were reviewed according to the STAndards for the Reporting of Diagnostic accuracy (STARD) method. A qualitative synthesis of the included studies was undertaken.

RESULTS: Fifteen studies with 699 patients with FH and 868 non-FH participants were included. Among the non-FH participants, 26 individuals had other documented Achilles tendon pathology (trauma or overuse). Evaluation with the STARD checklist suggested that the quality of evidence was low. US imaging and MRI may have acceptable sensitivity in detecting tendon thickening associated with ATX. There is a wide range in the suggested thickness thresholds and in the estimates of diagnostic accuracy.

CONCLUSIONS: A small amount of low-quality evidence suggests that ultrasonography or MRI can improve clinicians' accuracy in identifying ATX in people with FH, thereby identifying those with more severe coronary artery disease.