Abstract
Background and Objectives: Familial hypercholesterolemia (FH) is the most common genetic cause of cardiovascular disease. This study was aimed to 1) compare Achilles tendon thickness and characteristics using skin calipers, plain radiograph of lateral heels and ultrasonography in 63 FH patients (diagnosed using the Dutch Lipid Clinic Network [DLCN] score above 3 [possible, probable or definite FH]), 58 non-FH patients with elevated LDL-cholesterol (LDL-C) >130 mg/dL and 55 subjects with LDL-C below 130 mg/dL and determine the cutoff values with the highest diagnostic accuracy for FH diagnosis among Thai patients. 2) compare the coronary calcium score (CAC) and aortic valve calcium (AoVC) score using computed tomography in 62 FH patients and 58 non-FH patients Results: 1) Skinfold calipers demonstrated 61% accuracy for diagnosing FH. An anteroposterior (AP) diameter on plain radiographs ≥7.7 mm showed 75% sensitivity, 82% specificity, and 80% accuracy whereas ultrasonographic thickness ≥6.4 mm showed 46% sensitivity, 93% specificity and 76% accuracy and tendon area ≥78 mm2 showed 47% sensitivity, 93% specificity and 77% accuracy. Tendon border irregularities, diffuse hypoechogenicity and calcification were reported in a higher percentage of patients with FH compared with the other 2 groups. 2) FH participants had a nonsignificantly higher CAC score than that of non-FH participants (56.90 AU (0-2,370.5 AU) vs. 26.65 AU (0-512 AU), P = 0.105) with a higher proportion of patients who had a CAC score >0 AU (50.0% vs. 36.2%, P = 0.476). In addition, the FH group also had a greater proportion of subjects who had an AoVC score >0 AU (16.1% vs. 1.7%, P = 0.006). The CAC score of all participants was strongly correlated with age, total LDL-C burden, Achilles tendon thickness and a Thai CV risk score (R = 0.530, 0.364, 0.293 and 0. 528 respectively, P <0.005). Age, Achilles tendon thickness and statin use were significantly associated with CAC >0 AU (OR 14.30 for age >56 years, P = 0.002, OR 11.91, P = 0.005 and OR 5.91, P = 0.007, respectively) Conclusions: 1) Achilles tendon thickness measured by calipers showed low accuracy for diagnosis of FH. An AP diameter on plain radiographs demonstrated highest sensitivity and accuracy, whereas ultrasonographic thickness and area of Achilles tendon showed high specificity. Tendon irregularities, diffuse hypoechogenicity and calcification might serve as supportive findings. These findings may be helpful for the diagnostic criteria for FH in Thailand. 2) FH patients exhibited nonsignificantly higher CAC score than that of non-FH subjects, but the proportion of patients with AoVC >0 was significantly higher. Age, Achilles tendon thickness and statin use were associated with the CAC score >0 in all patients. These findings may be useful in tailoring treatment based on an individual risk of a particular subject.
