Complex Coronary Artery Lesions in a Young Woman With an Acute Myocardial Infarction and Genetically Confirmed Familial Hypercholesterolemia: A Case Report and Literature Review From a Developing Country

Abstract

Familial hypercholesterolemia (FH) is a genetic disorder characterized by elevated levels of low-density lipoprotein cholesterol (LDL-C) in the blood from an incredibly early age. This condition leads to the early development of atherosclerotic arterial diseases, which can manifest even in the first few decades of life. Mutations in genes related to the LDL receptor (LDL-R), apolipoprotein B (APOB), and proprotein convertase subtilisin/kexin type 9 (PCSK9) are the main molecular mechanisms causing familial hypercholesterolemia. This case involves a 44-year-old Vietnamese female who presented at the emergency department with chest pain and was diagnosed with acute myocardial infarction (AMI) complicated by cardiogenic shock. Clinical signs and an elevated LDL-C level pointed to prolonged exposure to high cholesterol. A Dutch Lipid Clinic Network (DLCN) score of 10 further supported the diagnosis of FH. The reverse T-stenting and small protrusion (TAP) technique was selected and successfully employed to stent the LMCA, left anterior descending artery (LAD) and left circumflex artery (LCx). This technique was chosen due to its simplicity and rapid execution, making it particularly suitable in situations of cardiogenic shock where time-consuming procedures should be avoided. Genetic testing confirmed a heterozygous pathogenic mutation in the LDL-R gene, corroborating the clinical diagnosis of FH. The patient's condition has gradually stabilized, and they have been discharged from the hospital. The patient is currently being monitored as an outpatient at the cardiology clinic. This case emphasizes the importance of considering FH in patients with premature cardiovascular events by applying the clinical diagnostic criteria and confirming by genetic analysis. It also highlights advanced interventional techniques for managing complex coronary lesions, such as reverse TAP.

Keywords: familial hypercholesteremia; gene; ldl-c; ldl-r; myocardial infarction.

Figure 1. The xanthelasma sign on both eyelids

The green arrow indicates the xanthelasma on the eyelid.

Figure 2. The patient's electrocardiogram at admission revealed sinus tachycardia; ST elevation from V2 to V6; DI; and aVL.

The faint red dashed border indicates the leads with ST elevation.

Figure 3. Pedigree and mutation analysis of the FH family

Nine direct relatives of the patient (II6) were advised to undergo genetic mutation testing using the Sanger method. Among them, the patient’s two sisters (II3 and II4) and two daughters (III1 and III2) were found to carry the genetic mutation at position (LDL-R) .664T>C (p.Cys222Arg).

Figure 4. Sequencing results of chromosome 19 with a variant (LDL-R): c.664T>C

The Sanger sequencing results for a direct relative of the patient (designated as II3 in Figure 3) revealed a heterozygous point mutation at nucleotide position 664, where T is replaced by C, resulting in the substitution of the amino acid cysteine with arginine at codon 222 of chromosome 19.