Abstract
Introduction
The International Atherosclerosis Society (IAS) has proposed “severe familial hypercholesterolemia (FH)” as a FH phenotype with the highest cardiovascular risk. Coronary artery disease (CAD) represents a major atherosclerotic change in FH patients. Given their higher LDL-C level and atherogenic clinical features, more extensive formation of atherosclerosis cardiovascular disease including not only CAD but stroke/peripheral artery disease (PAD) may more frequently occur in severe FH.
Methods
481 clinically-diagnosed heterozygous FH subjects were analyzed. Severe FH was defined as untreated LDL-C>10.3 mmol/l, LDL-C>8.0 mmol/l+ 1 high-risk feature, LDL-C>4.9 mmol/l + 2 high-risk features or presence of clinical ASCVD according to IAS proposed statement. Cardiac (cardiac death and ACS) and non-cardiac (stroke and peripheral artery disease) events were compared in severe and non-severe FH subjects.
Results
Severe FH was identified in 50.1% of study subjects. They exhibit increased levels of LDL-C and Lipoprotein (a) with a higher frequency of LDLR mutation. Furthermore, a proportion of %LDL-C reduction>50% was greater in severe FH under more lipid-lowering therapy (Table). However, during the observational period (median=6.3 years), severe FH was associated with a 5.9-fold (95% CI, 2.05–25.2; p=0.004) and 5.8-fold (95% CI, 2.02–24.7; p=0.004) greater likelihood of experiencing cardiac-death/ACS and stroke/PAD, respectively (picture). Multivariate analysis demonstrated severe FH as an independent predictor of both cardiac-death/ACS (hazard ratio=3.39, 95% CI=1.12–14.7, p=0.02) and stroke/PAD (hazard ratio=3.38, 95% CI=1.16–14.3, p=0.02) events.
Clinical characteristics of severe FH Non-severe FH Severe FH P-value Baseline LDL-C (mmol/l) 5.3±1.5 6.6±2.0 <0.0001 Lp(a) (mg/dl) 15 [8–28] 21 [10–49] <0.0001 LDLR mutation (%) 49.6% 58.9% 0.00398 On-treatment LDL-C (mmol) 133 [106–165] 135 [103–169] 0.9856 %LDL-C reduction>50% 21.3% 49.8% <0.0001 High-intensity statin (%) 13.3% 42.3% <0.0001 PCSK9 inhibitor (%) 6.3% 21.2% <0.0001
Clinical outcome
Conclusions
Severe FH subjects exhibit substantial atherosclerotic risks for coronary, carotid and peripheral arteries despite lipid lowering therapy. Our finding underscore the screening of systemic arteries and the adoption of further stringent lipid management in severe FH patients.
Absolute risk of cardiovascular disease events, and blood pressure‐ and lipid‐lowering therapy in Australia
