Background: Although risk factors for atherosclerotic cardiovascular disease (ASCVD) in familial hypercholesterolemia (FH) have been described, models for predicting incident ASCVD have not been reported. Our aim was to use the SAFEHEART registry (Spanish Familial Hypercholesterolemia Cohort Study) to define key risk factors for predicting incident ASCVD in patients with FH. Methods: SAFEHEART is a multicenter, nationwide, long-term prospective cohort study of a molecularly defined population with FH with or without previous ASCVD. Analyses to define risk factors and to build a risk prediction equation were developed, and the risk prediction equation was tested for its ability to discriminate patients who experience incident ASCVD from those who did not over time. Results: We recruited 2404 adult patients with FH who were followed up for a mean of 5.5 years (SD, 3.2 years), during which 12 (0.5%) and 122 (5.1%) suffered fatal and nonfatal incident ASCVD, respectively. Age, male sex, history of previous ASCVD, high blood pressure, increased body mass index, active smoking, and low-density lipoprotein cholesterol and lipoprotein(a) levels were independent predictors of incident ASCVD from which a risk equation with a Harrell C index of 0.85 was derived. The bootstrap resampling (100 randomized samples) of the original set for internal validation showed a degree of overoptimism of 0.003. Individual risk was estimated for each person without an established diagnosis of ASCVD before enrollment in the registry by use of the SAFEHEART risk equation, the modified Framingham risk equation, and the American College of Cardiology/American Heart Association ASCVD Pooled Cohort Risk Equations. The Harrell C index for these models was 0.81, 0.78, and 0.8, respectively, and differences between the SAFEHEART risk equation and the other 2 were significant ( P =0.023 and P =0.045). Conclusions: The risk of incident ASCVD may be estimated in patients with FH with simple clinical predictors. This finding may improve risk stratification and could be used to guide therapy in patients with FH. Clinical Trial Registration: URL: http://clinicaltrials.gov . Unique identifier: NCT02693548.

Objective—: Heterozygous familial hypercholesterolemia (FH) is the most common premature atherosclerotic cardiovascular disease (ASCVD)–related monogenic disorder, and it is associated with ischemic heart disease. There is limited information whether FH increases the risk of peripheral arterial and cerebrovascular disease. Our aim was to analyze ASCVD prevalence and characteristics in different arterial territories in a large FH population, to compare them with an unaffected control population and to determine which factors are associated to ASCVD. Approach and Results—: SAFEHEART (Spanish Familial Hypercholesterolaemia Cohort Study) is an ongoing registry of molecularly defined patients with heterozygous FH in Spain. ASCVD in the different arterial territories was analyzed, as well as individual characteristics, genetic variables, and lipid-lowering therapies. The study recruited 4132 subjects (3745 ≥18 years); 2,752 of those enrolled were molecularly diagnosed FH cases. Median age was 44.0 years (45.9% men) and 40 years (46.6% men) in FH patients and unaffected relatives ( P <0.001). ASCVD was present in 358 (13.0%) and 47 (4.7%) FH patients and unaffected relatives, respectively ( P <0.001). History of premature ASCVD was more prevalent in FH patients (9.4% and 2.4% in FH patients and unaffected relatives, respectively; P 50 mg/dL were independently associated with ASCVD. Conclusions—: The prevalence of ASCVD is higher, and the involvement of the arterial territories is different in FH patients when compared with their unaffected relatives. Age, male sex, increased body mass index, hypertension, type 2 diabetes mellitus, smoking habit, and lipoprotein(a) >50 mg/dL were independently associated to ASCVD. Clinical Trial Registration—: URL: https://www.clinicaltrials.gov . Unique identifier: NCT02693548.

Background: The effect of alirocumab, a PCSK9 (proprotein convertase subtilisin/kexin type 9) inhibitor, on coronary plaque burden in patients with familial hypercholesterolemia has not been addressed. Our aim was to assess changes in coronary plaque burden and its characteristics after treatment with alirocumab by quantification and characterization of atherosclerotic plaque throughout the coronary tree on the basis of a noninvasive analysis of coronary computed tomographic angiography in asymptomatic subjects with familial hypercholesterolemia receiving optimized and stable treatment with maximum tolerated statin dose with or without ezetimibe. Methods: This study is a phase IV, open-label, multicenter, single-arm clinical trial to assess changes in coronary plaque burden and its characteristics after 78 weeks of treatment with alirocumab in patients with familial hypercholesterolemia without clinical atherosclerotic cardiovascular disease. Participants underwent an initial coronary computed tomographic angiography at baseline and another at 78 weeks. Every patient received 150 mg of alirocumab subcutaneiously every 14 days in addition to high-intensity statin therapy. The main outcome was the change on coronary plaque burden and its characteristics by quantification and characterization of atherosclerotic plaque throughout the coronary tree on the basis of analysis of coronary computed tomographic angiography. Results: The study was completed by 104 patients. The median age was 53.3 (46.2–59.4) years. Of these patients, 54 were women (51.9%). Median low-density lipoprotein cholesterol was 138.9 (117.5–175.3) mg/dL at entry and 45.0 (36.0–65.0) mg/dL at follow-up ( P <0.001). Coronary plaque burden changed from 34.6% (32.5%–36.8%) at entry to 30.4% (27.4%–33.4%) at follow-up ( P <0.001). A significant change in the characteristics of the coronary atherosclerosis was also found: an increase in the proportion of calcified (+0.3%; P <0.001) and mainly fibrous (+6.2%; P <0.001) plaque, accompanied by a decrease in the percentage of fibro-fatty (–3.9%; P <0.001) and necrotic plaque (–0.6%; P <0.001). Conclusions: Treatment with alirocumab in addition to high-intensity statin therapy resulted in significant regression of coronary plaque burden and plaque stabilization on coronary computed tomographic angiography over 78 weeks in these groups of patients with familial hypercholesterolemia without clinical atherosclerotic cardiovascular disease. ARCHITECT (Effect of Alirocumab on Atherosclerotic Plaque Volume, Architecture and Composition) could link and explain ODYSSEY OUTCOMES (Evaluation of Cardiovascular Outcomes After an Acute Coronary Syndrome During Treatment With Alirocumab) results. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT05465278.