Aorta of young and middle-aged heterozygous familial hypercholesterolemia patients shows no functional or morphological impairment assessed by MRI

Is There a Role for Imaging Youth at Risk of Atherosclerosis?

PURPOSE OF REVIEW

Cardiovascular (CV) risk factors such as dyslipidemia, hypertension, diabetes, and obesity are associated with an increased risk for CV events in adults. Noninvasive measures of vascular health are associated with these CV events and can potentially help risk stratify children with CV risk factors. The purpose of this review is to summarize recent literature regarding vascular health in children with cardiovascular risk factors.

RECENT FINDINGS

Adverse changes in pulse wave velocity, pulse wave analysis, arterial distensibility, and carotid intima-media thickness are seen in children with CV risk factors supporting potential utility in risk stratification. Assessing vascular health in children can be challenging due to growth-related changes in vasculature, multiple assessment modalities, and differences in normative data. Vascular health assessment in children with cardiovascular risk factors can be a valuable tool for risk stratification and help identify opportunities for early intervention. Future areas of research include increasing normative data, improving conversion of data between different modalities, and increasing longitudinal studies in children linking childhood risk factors to adult CV outcomes.

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.

Pediatric heterozygous familial hypercholesterolemia patients have locally increased aortic pulse wave velocity and wall thickness at the aortic root

Familial hypercholesterolemia (FH) is an autosomal dominant disorder that affects 1 in 250 people. Aortic stiffness, measured by pulse wave velocity (PWV), is an independent predictor for cardiovascular events. Young FH patients are a unique group with early vessel wall disease that may serve to elucidate the determinants of aortic stiffness. We hypothesized that young FH patients would have early changes in aortic stiffness compared to healthy, age- and sex-matched reference values. Thirty-three FH patients ( ≥ 7 years age; mean age 14.6 ± 3.3 years; 26/33 on statin therapy) underwent cardiac MRI. PWV was determined using propagation of flow waveform from aortic arch phase contrast images. Distensibility and aortic wall thickness (AWT) were measured at the ascending, proximal descending, and diaphragmatic aorta. Ventricular volumes and left ventricular (LV) myocardial mass were measured from 2D cine images. These parameters were compared to age- and sex-matched reference values. FH patients had significantly higher PWV (4.5 ± 0.8 vs. 3.5 ± 0.3 m/s; p < 0.001), aortic distensibility, and ascending aortic wall thickness (1.37 ± 0.18 vs. 1.30 ± 0.02 mm; p < 0.05) compared to reference. There was no difference in aortic area or descending aortic wall thickness between groups. Young FH patients had aortic changes with increased aortic pulse wave velocity in the setting of increased aortic distensibility, accompanied by increased thickness of the ascending aortic wall. Presence of these early findings in young patients despite the majority being on statin therapy support enhanced screening and aggressive treatment of familial hypercholesterolemia to prevent potential future cardiovascular events.

[Alterations in arterial compliance of dyslipidemic patients]

INTRODUCTION

We studied the alteration on the distensibility of the arterial walls caused by dyslipidemia LDLc dependent, along the decades of life, by means of a study of the radial artery pulse wave.

METHODS

We made an analysis of the radial artery pulse wave records acquired by means a movement displacement sensor, placed on radial palpation area. We recruited 100 dyslipidemic men without other cardiovascular risk factors, between the 3rd and the 6th decade. We identified the reflected wave in the records and we computed the augmentation index in order to quantify its amplitude and position. This index is useful to assess the endothelial dysfunction. Besides, we defined a velocity coefficient as the ratio between the size of the individuals and the delay time between the peak of the systolic wave and the arrival of the reflected wave. Results were compared against those obtained in a group of 161 healthy volunteers.

RESULTS

We found that dyslipidemic patients presented augmentation index values similar to controls until the fourth decade, increasing thereafter with significant differences only in the 6th decade. No significant differences were found in the velocity index in any of the ages studied.

CONCLUSIONS

We conclude that alterations produced by dyslipidemia take decades to manifest, and they begin affecting the mechanism of vasodilation of distal arteries with highest proportion of smooth muscle, without altering the proximal conduit arteries with more elastin content.

Detection of subclinical atherosclerosis in familial hypercholesterolemia using non-invasive imaging modalities

OBJECTIVES

To investigate the extent of subclinical atherosclerosis in asymptomatic familial hypercholesterolemia (FH) patients using non-invasive images techniques.

PATIENTS, METHODS AND RESULTS

The atherosclerotic burden of 36 molecularly defined FH patients (18 males, 45.7±10.9 years) without evidence of cardiovascular disease receiving lipid-lowering treatment and 19 (47.8±11.3 years) controls was investigated. Descending thoracic aorta magnetic resonance imaging (MRI) was performed in a 1.5 T equipment with T1 and T2 sequences to characterize atherosclerotic plaques and to measure aortic wall volumen. Carotid intima-media thickness (cIMT) and presence of plaques were measured using B-mode carotid ultrasound. Mean aortic wall volumen, cIMT and atherosclerotic plaques in aorta were significantly higher in FH cases (P<0.001). A significant correlation between aortic wall volume and cIMT was observed (P<0.01). Aortic MRI detected plaques in 94% and carotid ultrasound in 14% of cases. Lipid-rich plaques were observed only in FH cases (33%) and were associated with family history of premature coronary artery disease (P<0.05).

CONCLUSIONS

Asymptomatic middle-aged FH patients have significantly higher atherosclerotic burden than controls. cIMT has shown a significant correlation with aortic wall volume and MRI allowed the detection of lipid-rich plaques in FH subjects that were associated with family history of premature coronary artery disease.

Short-term exposure to exogenous lipids in premature infants and long-term changes in aortic and cardiac function

OBJECTIVE

Intravenous lipid use is associated with an acute hyperlipidemia, but long-term consequences have not been studied. We investigated whether elevated lipids in humans during the critical period of preterm neonatal life have a long-term impact on aortic and myocardial function relevant to adult disease.

METHODS AND RESULTS

We followed up 102 subjects born prematurely and now aged 23 to 28 years. Eighteen received intravenous lipids as neonates and were matched to controls with equivalent perinatal characteristics. Global and regional aortic stiffness and left ventricular function were assessed by cardiovascular magnetic resonance. Those who received intravenous lipids had greater aortic stiffness in early adulthood (P=0.0002), with greater stiffness in the abdominal aorta (P=0.012). The relationship was graded according to the elevation in neonatal cholesterol induced by intravenous lipids (P<0.0001) but not other metabolic parameters altered by the infusion. Peak systolic circumferential strain was also reduced in the lipid group (P=0.006), which, again, was proportional to neonatal cholesterol level (P<0.01).

CONCLUSIONS

Aortic and myocardial function in young adulthood is associated with intralipid exposure during neonatal life for preterm infants, in a graded manner related to the rise in cholesterol. Circulating cholesterol during critical developmental periods may have long-term impacts on the human cardiovascular system.

Compliance of the aorta in two diseases affecting vascular elasticity, familial hypercholesterolemia and diabetes: a MRI study

Arterial elasticity changes in familial hypercholesterolemia (FH) and diabetes mellitus (DM) with different but overlapping mechanisms. We compared aortic elasticity between 19 FH patients with the same mutation, 18 type 2 DM patients, and 30 controls, all aged 48 to 64. They underwent aortic magnetic resonance imaging, risk-factor assessment, and carotid and femoral ultrasound measurements. All patients were on adequate cardiovascular medication including statins and had established coronary heart disease (CHD). FH patients had longer-duration CHD (13.3 +/- 7.7 years) than did DM patients (5.0 +/- 3.1). Aortic compliance in the descending thoracic (DM 0.38 +/- 0.14 vs control 0.53 +/- 0.19, P = 0.032) and abdominal aorta (DM 0.45 +/- 0.20 vs control 0.66 +/- 0.25, P = 0.011) was lower in DM patients than in controls, whereas no significant difference existed between FH patients and controls. Carotid and femoral intima-media thickness was greater in FH and DM patients than in controls with no difference between patient groups. Carotid or femoral plaques appeared in 15 (79%) FH and in 10 (56%) DM patients. One control had a femoral plaque. Five FH patients showed stenosis, occlusion or both in carotid arteries. In our opinion, DM patients' lower compliance reflect mainly arterial media affecting arteriosclerosis, while FH patients' plaque status and longer duration of CHD suggest more advanced atherosclerosis. The FH patients may therefore be at increased risk for atherothrombotic events. However, due to small patient material, larger confirmatory studies are needed.