Prevalence, clinical features and prognosis of familial hypercholesterolemia in Chinese Han patients with acute coronary syndrome after a coronary event: a retrospective observational study

Background: Familial hypercholesterolemia (FH) is an autosomal semi-dominant disease, characterized by markedly elevated levels of low-density lipoprotein cholesterol (LDL-c) from conception and accelerated atherosclerotic cardiovascular disease, often resulting in early death. The aim of this study was to evaluate the prevalence of clinically defined FH in Chinese Han patients with acute coronary syndrome (ACS) and compare the long-term prognosis of ACS patients with and without FH receiving lipid-lowering therapy containing statins after a coronary event.

Methods: All ACS patients were screened at the Second Affiliated Hospital of Xi'an Jiaotong University between Jan 2019 and Sep 2020, and 531 participants were enrolled. All were examined for FH under the Dutch Lipid Clinical Network (DLCN) criteria, and those patients were divided into definite/probable FH, possible FH and unlikely FH. The severity of coronary artery disease was evaluated by the Gensini scoring system. Plasma levels of total cholesterol (TC), triacylglycerol (TG), HDL-cholesterol (HDL-c), LDL-cholesterol (LDL-c), very low-density lipoproteins-cholesterol (VLDL-c), apolipoprotein A1 (apoA1), apolipoprotein B (apoB) and lipoprotein (a) (Lp(a)) were determined centrally at baseline and the last follow-up visit in the fasting state. The non-high-density lipoprotein cholesterol (non-HDL-c) concentration, the TC/HDL-c and apoB/apoA1 ratios were calculated. After FH patients received lipid-lowering treatment containing statin, the target LDL-c levels recommended by the guidelines (LDL-c < 1.8 mmol/L or < 1.4 mmol/L and a reduction > 50% from baseline) were evaluated, and the occurrence of major adverse cardiovascular and cerebrovascular events (MACCE) during the 12-month follow-up was recorded.

Results: The prevalence of clinically definite or probable FH was 4.3%, and the prevalence of possible FH was 10.6%. Compared with the unlikely FH patients with ACS, the FH patients had higher levels of TC, LDL-c, apoB, Lp(a), non-HDL-c, TC/HDL-c and apoB/apoA1 ratio, more severe coronary artery diseases and greater prevalence of left main and triple or multiple vessel lesions. After lipid-lowering therapy containing statins, a minority of FH patients reached the target LDL-c levels defined by the guidelines (χ² = 33.527, P < 0.001). During the 12-month follow-up, a total of 72 patients experienced MACCE. The survival curve in patients in the FH group was significantly lower than that in the unlikely FH group (HR = 1.530, log-rank test: P < 0.05). Furthermore, the survival curve in patients with high LDL-c (≥ 1.8 mmol/L) was significantly lower than that in patients with low LDL-c (< 1.8 mmol/L) at the 12-month follow-up visit (HR = 1.394, log-rank test: P < 0.05). No significant difference was observed between patients with LDL-c levels ≥ 1.4 mmol/L and with < 1.4 mmol/L at the 12-month follow-up visit by using Kaplan-Meier survival analysis (HR = 1.282, log-rank test: P > 0.05).

Conclusions: FH was an independent risk factor for MACCE in adult patients after a coronary event during long-term follow-up. However, there was inadequate high-intensity statins prescriptions for high-risk patients in this current study. It is important for FH patients to optimize lipid-lowering treatment strategies to reach the target LDL-c level to improve the long-term prognosis of clinical outcomes.