Prevalence of heterozygous familial hypercholesterolemia and combined hyperlipidemia phenotype in very young survivors of myocardial infarction and their association with the severity of atheromatous burden

A Systematic Review on the Risk Modulators of Myocardial Infarction in the "Young"-Implications of Lipoprotein (a)

The presence of a myocardial infarction at a younger age is of special interest, considering the psychological and socioeconomic impact, as well as long-term morbidity and mortality. However, this group has a unique risk profile, with less traditional cardiovascular risk factors that are not well studied. This systematic review aims to evaluate traditional risk factors of myocardial infarction in the "young", highlighting the clinical implications of lipoprotein (a). We performed a comprehensive search using Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) standards; we systematically searched the PubMed, EMBASE, and Science Direct Scopus databases, using the terms: "myocardial infarction", "young", "lipoprotein (a)", "low-density lipoprotein", "risk factors". The search identified 334 articles which were screened, and, at the end, 9 original research articles regarding the implications of lipoprotein (a) in myocardial infarction in the "young" were included in the qualitative synthesis. Elevated lipoprotein (a) levels were independently associated with an increased risk of coronary artery disease, especially in young patients, where this risk increased by threefold. Thus, it is recommended to measure the lipoprotein (a) levels in individuals with suspected familial hypercholesterolaemia or with premature atherosclerotic cardiovascular disease and no other identifiable risk factors, in order to identify patients who might benefit from a more intensive therapeutic approach and follow-up.

Causes, Angiographic Characteristics, and Management of Premature Myocardial Infarction: JACC State-of-the-Art Review

Among patients presenting with acute myocardial infarction (AMI), the proportion of young individuals has increased in recent years. Although coronary atherosclerosis is less extensive in young patients with AMI, with higher prevalence of single-vessel disease and rare left main involvement, the long-term prognosis is not benign. Young patients with AMI with obstructive coronary artery disease have similar risk factors as older patients except for higher prevalence of smoking, lipid disorders, and family history of premature coronary artery disease, and lower prevalence of diabetes mellitus and hypertension. Smoking cessation is by far the most effective secondary preventive measure. Myocardial infarction with nonobstructive coronary arteries is a relatively common clinical entity (10%-20%) among young patients with AMI, with intravascular and cardiac magnetic resonance imaging being key for diagnosis and potentially treatment. Spontaneous coronary artery dissection is a frequent pathogenetic mechanism of AMI among young women, requiring a high degree of suspicion, especially in the peripartum period.

The Pathogenic Role of Foam Cells in Atherogenesis: Do They Represent Novel Therapeutic Targets?

BACKGROUND

Foam cells, mainly derived from monocytes-macrophages, contain lipid droplets essentially composed of cholesterol in their cytoplasm. They infiltrate the intima of arteries, contributing to the formation of atherosclerotic plaques.

PATHOGENESIS

Foam cells damage the arterial cell wall via the release of proinflammatory cytokines, free radicals, and matrix metalloproteinases, enhancing the plaque size up to its rupture.

THERAPY

A correct dietary regimen seems to be the most appropriate therapeutic approach to minimize obesity, which is associated with the formation of foam cells. At the same time, different types of antioxidants have been evaluated to arrest the formation of foam cells, even if the results are still contradictory. In any case, a combination of antioxidants seems to be more efficient in the prevention of atherosclerosis.

Familial Hypercholesterolemia, Familial Combined Hyperlipidemia, and Elevated Lipoprotein(a) in Patients With Premature Coronary Artery Disease

BACKGROUND

Familial hypercholesterolemia (FH), familial combined hyperlipidemia (FCHL), and elevated lipoprotein (a) (Lp[a]) increase risk of premature coronary artery disease (CAD). The objective of this study was to assess the prevalence of FH, FCHL, elevated Lp(a) and their impact on management in patients with premature CAD.

METHODS

We prospectively recruited men ≤ 50 years and women ≤ 55 with obstructive CAD. FH was defined as Dutch Lipid Clinic Network scores ≥ 6. FCHL was defined as apolipoprotein B > 1.2 g/L, triglyceride and total cholesterol > 90th population percentile, and family history of premature cardiovascular disease. Lp(a) ≥ 50 mg/dL was considered to be elevated.

RESULTS

Among 263 participants, 9.1% met criteria for FH, 12.5% for FCHL, and 19.4% had elevated Lp(a). Among patients with FH, 37.5% had FH-causing DNA variants. Patients with FH, but not other dyslipidemias, were more likely than nondyslipidemic patients to have received lipid-lowering therapy before presenting with CAD (33.3% vs 12.3%, P = 0.04) and combined lipid-lowering therapy after the presentation (41.7% vs 7.7%, P < 0.001). One year after presentation, 58.3%, 54.5%, and 58.8% of patients with FH, FCHL, and elevated Lp(a) had low-density lipoprotein cholesterol (LDL-C) < 1.8 mmol/L, respectively, compared with 68.0 % in reference group. Patients with FCHL were more likely to have non-high-density lipoprotein (HDL) and apolipoprotein B above recommended lipid goals (70.0% and 87.9%, respectively).

CONCLUSIONS

FH, FCHL, and elevated Lp(a) are common in patients with premature CAD and have differing impact on treatment and achievement of lipid targets. Assessment for these conditions in patients with premature CAD provides valuable information for individualized management.

Heterozygous familial hypercholesterolemia: prevalence and control rates

Introduction: Heterozygous familial hypercholesterolemia (heFH) is associated with a very high risk for cardiovascular events. Treatment with potent statins substantially reduces cardiovascular morbidity in these patients. Moreover, combination therapy with statins plus ezetimibe and/or proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors facilitates achievement of low-density lipoprotein cholesterol (LDL-C) targets in patients with heFH. However, heFH remains underdiagnosed and undertreated worldwide.Areas covered: In this review, we summarize current evidence on the prevalence and control rates of heFH. Accumulating data suggest that heFH is one of the most common hereditary metabolic disorders, affecting approximately 1 in every 300 individuals. However, only a small minority of patients with heFH achieve LDL-C targets, even in high-income countries and in subjects followed-up in specialized lipid clinics.Expert opinion: Given the underdiagnosis of heFH using cascade and opportunistic screening, wider, population-based screening strategies should be evaluated for their feasibility and cost-effectiveness if we aspire to timely diagnosis and therefore prevention of cardiovascular morbidity and mortality in this very high risk population. Overcoming inertia in uptitrating statin dose, adding ezetimibe and/or PCSK9 inhibitors along with more generous reimbursement for lipid-lowering agents in patients with heFH are essential for improving goal attainment rates.

Coronary lesion complexity in patients with heterozygous familial hypercholesterolemia hospitalized for acute myocardial infarction: data from the RICO survey

BACKGROUND

Although patients with familial heterozygous hypercholesterolemia (FH) have a high risk of early myocardial infarction (MI), the coronary artery disease (CAD) burden in FH patients with acute MI remains to be investigated.

METHODS

The data for all consecutive patients hospitalized in 2012-2019 for an acute MI and who underwent coronary angiography were collected from a multicenter database (RICO database). FH (n = 120) was diagnosed using Dutch Lipid Clinic Network criteria (score ≥ 6). We compared the angiographic features of MI patients with and without FH (score 0-2) (n = 234) after matching for age, sex, and diabetes (1:2).

RESULTS

Although LDL-cholesterol was high (208 [174-239] mg/dl), less than half of FH patients had chronic statin treatment. When compared with non-FH patients, FH increased the extent of CAD (as assessed by SYNTAX score; P = 0.005), and was associated with more frequent multivessel disease (P = 0.004), multiple complex lesions (P = 0.022) and significant stenosis location on left circumflex and right coronary arteries. Moreover, FH patients had more multiple lesions, with an increased rate of bifurcation lesions or calcifications (P = 0.021 and P = 0.036, respectively). In multivariate analysis, LDL-cholesterol levels (OR 1.948; 95% CI 1.090-3.480, P = 0.024) remained an independent estimator of anatomical complexity of coronary lesions, in addition to age (OR 1.035; 95% CI 1.014-1.057, P = 0.001).

CONCLUSIONS

FH patients with acute MI had more severe CAD, characterized by complex anatomical features that are mainly dependent on the LDL-cholesterol burden. Our findings reinforce the need for more aggressive preventive strategies in these high-risk patients, and for intensive lipid-lowering therapy as secondary prevention.

The brave new world of genetic testing in the management of the dyslipidaemias

PURPOSE OF REVIEW

With the exception of familial hypercholesterolaemia, the value of genetic testing for managing dyslipidaemias is not established. We review the genetics of major dyslipidaemias in context of clinical practice.

RECENT FINDINGS

Genetic testing for familial hypercholesterolaemia is valuable to enhance diagnostic precision, cascade testing, risk prediction and the use of new medications. Hypertriglyceridaemia may be caused by rare recessive monogenic, or by polygenic, gene variants; genetic testing may be useful in the former, for which antisense therapy targeting apoC-III has been approved. Familial high-density lipoprotein deficiency is caused by specific genetic mutations, but there is no effective therapy. Familial combined hyperlipidaemia (FCHL) is caused by polygenic variants for which there is no specific gene testing panel. Familial dysbetalipoproteinaemia is less frequent and commonly caused by APOE ε2ε2 homozygosity; as with FCHL, it is responsive to lifestyle modifications and statins or/and fibrates. Elevated lipoprotein(a) is a quantitative genetic trait whose value in risk prediction over-rides genetic testing; treatment relies on RNA therapeutics.

SUMMARY

Genetic testing is not at present commonly available for managing dyslipidaemias. Rapidly advancing technology may presage wider use, but its worth will require demonstration of cost-effectiveness and a healthcare workforce trained in genomic medicine.

JCL roundtable: Pediatric lipidology

This JCL Roundtable discussion probes the knowledge of 3 experts in pediatric lipidology, an emerging discipline both in the United States and internationally. In the 1990s, only 3 US institutions could be said to have dedicated pediatric lipid clinics; that number has grown to 25 today. The Pediatric Atherosclerosis Prevention and Lipidology Group of the National Lipid Association has regular teleconferences to support advocacy and convey best practices. Guidelines for pediatric lipidology initially focused on low-density lipoprotein cholesterol in 1992 as part of the National Cholesterol Education Program. Today the most comprehensive coverage comes from the 2011 National Heart Lung and Blood Institute Pediatric Guidelines. Universal screening was recommended for children between ages 9 and 11 years and teenagers/young adults between 17 to 21 years, a position echoed as "may be recommended" by the 2018 AHA/ACC/Multisociety Cholesterol Guidelines. While pediatric lipidologists continue to treat uncommon genetic disorders, they increasingly confront an issue of epidemic proportions-dyslipidemia as the initial presentation of metabolic dysregulation associated with obesity. Consequences of such altered metabolism extend to atherosclerosis, diabetes, liver disease, and other serious problems in adult life. Pediatric lipid science and practice differ from adult experience in several ways, including importance of family and birth history as well as genetics/epigenetics, lack of general pediatricians' familiarity with lipid drugs, value of family counseling, need for biomarkers of early metabolic dysregulation, and anticipation of endpoints in adult life not fully defined by randomized clinical trials in children.

Non-coronary atherosclerotic cardiovascular disease in patients with familial hypercholesterolaemia

Objective: Familial hypercholesterolaemia (FH) is a common autosomal dominant inherited disease, affecting 1 in 200-500 individuals worldwide. FH is characterized by elevated circulating low-density lipoprotein cholesterol (LDL-C) concentrations. Its association with increased risk of coronary heart disease (CHD) (>10-fold, compared with patients without FH) is well documented. However, the association between FH and non-CHD atherosclerotic cardiovascular disease (ASCVD) risk has been poorly documented.Methods: PubMed was searched for English language publications regarding the association between FH and carotid artery stenosis, stroke, peripheral artery disease (PAD; lower limbs and other arterial beds), aortic valve calcification (AoVC), aortic and renal artery disease, chronic kidney disease, atrial fibrillation and heart failure, from conception until 22 December 2019.Results: Despite the small number of available studies, as well as their characteristics (sample size, diagnostic criteria used, retrospective or cross-sectional design), there is evidence for a positive association between FH and stroke, PAD or AoVC. More data are needed for definitive conclusions regarding aortic and renal artery disease, chronic kidney disease, atrial fibrillation and heart failure. There is paucity of data with respect to homozygous FH. Increased lipoprotein (a) concentrations, often seen in FH patients, may also contribute to this non-CHD atherosclerotic process. A key question is whether statins or other LDL-C-lowering therapies, provide an additional reduction in the risk of these less-recognized vascular and non-vascular complications in FH patients.Conclusions: Heterozygous FH is associated with increased risk for stroke, PAD and AoVC. Clinicians should take these non-CHD ASCVD aspects into consideration for optimal management of FH patients.

Foam Cells: One Size Doesn't Fit All

Chronic inflammation in many infectious and metabolic diseases, and some cancers, is accompanied by the presence of foam cells. These cells form when the intracellular lipid content of macrophages exceeds their capacity to maintain lipid homeostasis. Concurrently, critical macrophage immune functions are diminished. Current paradigms of foam cell formation derive from studies of atherosclerosis. However, recent studies indicate that the mechanisms of foam cell biogenesis during tuberculosis differ from those operating during atherogenesis. Here, we review how foam cell formation and function vary with disease context. Since foam cells are therapeutic targets in atherosclerosis, further research on the disease-specific mechanisms of foam cell biogenesis and function is needed to explore the therapeutic consequences of targeting these cells in other diseases.