Coronary arterial wall and atherosclerosis in youth (1-20 years): a histologic study in a northern Italian population

ANMCO POSITION PAPER: Prognostic and therapeutic relevance of non-obstructive coronary atherosclerosis

Atherosclerosis often affects the coronary arterial tree. Frequently the disease does not translate in significant narrowing of the vessels, thus determining only a non-obstructive disease. This condition that is described as non-obstructive coronary artery disease (NobsCAD) should be distinguished from the absence of disease (i.e. smooth coronary arteries) as it carries a specific prognostic value. The detection and reporting of NobsCAD should prompt preventive measures that can be individualized upon the degree of the underlying burden of disease. The accompanying clinical condition, the other cardiovascular risk factors present, and the description of the severity and extent of NobsCAD should provide the framework for an individualized treatment that should also consider the best available scientific evidence and guidelines. The description of NobsCAD represents important information to be collected whenever a coronary angiogram (both invasive and non-invasive) is performed. Treating the patient according to the presence and extent of NobsCAD offers prognostic benefits well beyond those offered by considering only the traditional cardiovascular risk factors. In order to reach this goal, NobsCAD should not be confused with the absence of coronary atherosclerosis or even ignored when detected as if it was a trivial information to provide.

Coronary Arteries: Normal Anatomy With Historical Notes and Embryology of Main Stems

Anatomy of subepicardial coronary arteries became a topic of investigation at autopsy in Florence (Italy) by Banchi in the early twentieth century, with the discovery of dominant and balanced patterns. Thereafter, in the 60's of the same century Baroldi in Milan did post-mortem injection with spectacular three-dimensional casts. Later Sones at the Cleveland Clinic introduced selective coronary arteriography for in vivo visualization of coronary arteries. In the present chapter we show these patterns, as well as normal variants of origin and course with questionable risk of ischemia, like myocardial bridge as well as origin of the left circumflex coronary artery from the right sinus with retroaortic course. As far as embryology, the coronary arteries and veins are epicardial in origin and finally connect the former with the aorta, and the latter with the sinus venosus. At the time of spongy myocardium, intramural blood supply derives directly by the ventricular cavities, whereas later, at the time of myocardial compaction, vascularization originates from the subepicardial network. The connection of the subepicardial plexus with the aorta occurs with prongs of the peritruncal ring, which penetrate the facing aortic sinuses. Septation of truncus arteriosus is not responsible for the final position of the coronary orifices. Infact in transposition of the great arteries coronary ostia are regularly located within facing sinuses of the anterior aorta.

Physical Activity and Trajectories of Cardiovascular Health Indicators During Early Childhood

OBJECTIVES

Cardiovascular disease prevention should begin in childhood. However, the influence of physical activity on cardiovascular health in early childhood is unknown. Our purpose in this study was to determine the effect of physical activity on trajectories of cardiovascular health indicators during early childhood.

METHODS

This prospective, observational cohort study (Health Outcomes and Physical Activity in Preschoolers) enrolled 418 3- to 5-year-olds with annual assessments for 3 years. Total physical activity (TPA) and moderate-to-vigorous physical activity (MVPA) were measured over 7 days via accelerometry. Cardiovascular health indicators included cardiovascular fitness (exercise time on a maximal treadmill test [treadmill time] and 1-minute heart rate recovery), resting arterial stiffness (whole-body pulse wave velocity and carotid β stiffness index), and seated systolic blood pressure. Data were analyzed by using linear mixed-effects modeling; effects are reported as unstandardized estimates (Est).

RESULTS

There were main effects of TPA and MVPA on treadmill time (Est = 0.004 [P = .005] and 0.008 [P = .001], respectively) and heart rate recovery (Est = 0.05 [P < .001] and 0.08 [P < .001], respectively). There was a main effect of TPA on pulse wave velocity (Est = -0.001; P = .02) and an MVPA × time interaction (Est = -0.002; P = .01). For carotid β stiffness index, the effect of a TPA × time interaction was not significant (Est = -0.002; P = .051); however, there was a significant MVPA × time interaction (Est = -0.003; P = .03). MVPA was associated with a slower rate of change in systolic blood pressure for girls (Est = 0.06; P = .009).

CONCLUSIONS

Children who engage in higher levels of physical activity during early childhood have better cardiovascular health indicators, with more intense physical activity (ie, MVPA) attenuating the stiffening of arteries.

Coronary Intimal Thickening Begins in Fetuses and Progresses in Pediatric Population and Adolescents to Atherosclerosis

The prevalence of coronary intimal thickening (IT) was assessed in fetuses and pediatric population. We studied the coronary arteries of 63 hearts obtained from fetuses, infants, children, and adolescents, deceased from noncardiac disease or trauma. Histomorphometric analysis, planimetry, and immunohistochemical studies were conducted. Intimal thickening consisted of proliferation of smooth muscle cells and scarce monocytes embedded in amorphous deposits within the internal elastic membrane (IEM). Intermingled lesions of intimal hyperplasia and parietal nonstenotic plaques were also observed. Intimal thickening was found in 10% of 20 fetuses, in 33.3% of 18 infants, 73.3% of 15 children, and 100% of 10 adolescents. A significant correlation (r = 0.671, P < 0.001) was found between the extent of IT and age. The IEM was duplicated or interrupted in 43% of patients, showing a positive correlation with the degree of IT (P = 0.01). Intimal thickening was predominantly found near bifurcation sites in the left anterior descending coronary artery (55.6%) and in zones free of bifurcation in the right coronary artery (75%). In conclusion, the prevalence and extension of IT lesions are higher at older ages within a young population. Intimal thickening may be regarded as the first event occurring in coronary preatherosclerosis, preceding lipid deposition.

Sudden coronary death in the young: Evidence of contractile phenotype of smooth muscle cells in the culprit atherosclerotic plaque

BACKGROUND

Culprit coronary atherosclerotic plaques (APs) from young sudden cardiac death (SCD) victims are mostly non-atheromatous, i.e., consisting of proliferative smooth muscle cells (SMCs). Coronary vasospasm has been advocated to explain plaque instability in the absence of thrombosis. Our aim was to characterize the SMC phenotype in the intima and media of coronary arteries from young SCD victims.

METHODS AND RESULTS

A total of 38 coronary artery segments were studied: (a) 18 APs from young (≤40 years old) SCD patients, (b) 9 APs from old (>40 years old) SCD patients, (c) 11 non-atherosclerotic coronary arteries from young patients (≤40 years old). Markers of differentiated SMCs such as α-smooth muscle actin (α-SMA), smooth muscle myosin heavy chains (SMMHCs), and heavy-caldesmon (h-CaD), were assessed in intima and media by immunohistochemistry and quantified morphometrically. In the intima, their expression was higher in non-atherosclerotic arteries (44.37 ± 3.03% for α-SMA, 14.21 ± 2.01% for SMMHCs, 8.90 ± 1.33% for h-CaD) and APs from young SCD victims (38.95 ± 2.29% for α-SMA, 11.92 ± 1.92% for SMMHCs, 8.93 ± 1.12% for h-CaD) compared with old patients (22.01 ± 3.56% for α-SMA, 6.39 ± 0.7% for SMMHCs, 3.00 ± 0.57% for h-CaD; all P statistically significant). The media of non-atherosclerotic arteries and APs from young SCD victims exhibited strong positivity for the differentiation markers unlike that of old patients.

CONCLUSIONS

SMCs of coronary APs as well as from the underlying media from young SCD victims exhibit strong contractile phenotype. In the setting of critical stenosis, both intima and media SMC contractility might contribute to transient coronary spasm leading to myocardial ischemia and SCD.

Sports Practices and Cardiovascular Risk in Teenagers

Background

Cardiovascular diseases are the leading cause of deaths in the world, and many events could be prevented by healthy life habits.

Objectives

To compare the occurrence of cardiovascular risk factors in adolescents enrolled at public schools in the city of Rio de Janeiro, including a renowned school for sport practices.

Methods

Cross-sectional study, convenience sampling of 422 students enrolled at the Experimental Olympic Gymnasium (EOG) and at Figueiredo Pimentel School (FP). Using descriptive analyses, continuous variables were expressed as mean and standard deviation or median and interquartile ranges, and the Student's t-test or the chi-square test, respectively, was used for comparisons. The sports were classified according to the metabolic equivalent of task (MET) (below or above 5).

Results

We included 274 students enrolled at the EOG and 148 at FP. Mean age was similar between schools -12.5 ± 1.6 years at FP and 12.6 ± 0.9 at the EOG; 65.5% of the students at FP and 43.8% of the students at the EOG were female (p < 0.01). Significant differences in the prevalence of hypertension (20% vs. 6.3%, p < 0.01) and borderline cholesterol levels (27.7% vs. 17.3%, p = 0.01) were found between FP and EOG students, respectively.

Conclusion

High prevalence of hypertension, overweight/obesity and altered blood lipid profile was found in this group of adolescents. Regular sports training program combined with little influence of their eating habits outside school may contribute to a better metabolic profile and reduction in cardiovascular risk factors in students. Public health measures are also need.

Early physiological markers of cardiovascular risk in community based adolescents with a depressive disorder

BACKGROUND

Depression is recognised as an independent cardiovascular risk factor in adults. Identifying this relationship early on in life is potentially important for the prevention of cardiovascular disease (CVD). This study investigated whether clinical depression is associated with multiple physiological markers of CVD risk in adolescents from the general community.

METHODS

Participants aged 12-18 years were recruited from the general community and screened for depressive symptoms. Individuals with high and low depressive symptoms were administered a diagnostic interview. Fifty participants, 25 with a current depressive episode and 25 matched healthy controls, subsequently completed cardiovascular assessments. Variables assessed were automatic brachial and continuous beat-to-beat finger arterial blood pressure, heart rate, vascular functioning by pulse amplitude tonometry following reactive hyperaemia and pulse transit time (PTT) at rest. Blood samples were collected to measure cholesterol, glucose and glycohaemoglobin levels and an index of cumulative risk of traditional cardiovascular risk factors was calculated.

RESULTS

Depressed adolescents had a significantly lower reactive hyperaemia index and shorter PTT, suggesting deterioration in vascular integrity and structure. Higher fasting glucose and triglyceride levels were also observed in the depressed group, who also had higher cumulative risk scores indicative of increased engagement in unhealthy behaviours and higher probability of advanced atherosclerotic lesions.

LIMITATIONS

The sample size and number of males who completed all cardiovascular measures was small.

CONCLUSIONS

Clinically depressed adolescents had poorer vascular functioning and increased CVD risk compared to controls, highlighting the need for early identification and intervention for the prevention of CVD in depressed youth.

The un-natural history of an adolescent with combined congenital and acquired heart disease

This study describes the un-natural history of a 16-year-old patient, presenting with a critical bicuspid aortic valve stenosis, who was initially treated in the neonatal period and later with a valvuloplasty. This focused the attention on palliative interventions that, in young adulthood or middle age, are usually related to several complications, until heart transplantation. The other important aspect of this case is the presence of a coronary atherosclerotic plaque producing a significant obstruction, in the setting of haemodynamic acute postoperative failure caused by the sudden aortic valve laceration and insufficiency. This favoured the transmural myocardial antero-septal evolution of the myocardial ischaemic-reperfusion damage. This case is peculiar in that it presents two unrelated entities in their natural history. The coronary lesion was an unexpected finding in an adolescent with congenital heart disease. The severity of the coronary lesion became haemodynamically significant as a combination of the hypoperfusion due to the massive aortic valve regurgitation following the acute failure of the aortic valve plasty and the vasoconstriction of the eccentric speared segment. Once again, the complete understanding of grown-up patients with congenital hart disease is mandatory together with the point that a close collaboration of a multidisciplinary team is essential for appropriate operative timing and planning the most suitable treatment option. Acquired heart diseases can rarely present in association in this group of patients and need to be taken into account.

Coronary Intimal Thickening in Newborn Babies and ≤1-Year-Old Infants

We performed a morphological characterization of intimal thickenings in coronary arteries in the very early stages of life to obtain insights into initial coronary atherogenesis. We examined specimens from 67 infants who had died of noncardiac causes within their first year of life. Serially cut sections were stained with hematoxylin-eosin, Azan, Alcian blue, acetic orceine, and immunotypified for CD68, CD34, and α-smooth muscle (SM) actin. Substantial changes were detected in about 1 of 3 participants. Alterations ranged from focal areas with mild myointimal thickening to diffuse moderate thickening. In those lesions, smooth muscle cells (SMCs) showed loss of polarity, infiltrating the subendothelium, mostly with rupture of the internal elastic lamina and without neoangiogenesis. Morphometrically, in musculoelastic intimal thickenings, neointimal thickness averaged 58.3 ± 17.8 µm, affecting 46% of the internal elastic membrane perimeter; lumen stenosis averaged 13.7% ± 5.0%. These lesions can be present very early in life and SMCs seem to play an essential role.

Perinatal and infant early atherosclerotic coronary lesions

OBJECTIVE

Because the fetal origin of coronary artery lesions is controversial, early atherosclerotic coronary artery lesions in late fetal stillborns and infants, as well as the possible atherogenic role of maternal cigarette smoking, were studied.

METHODS

Twenty-two fetal death and 36 sudden infant death syndrome victims were examined by autopsy. In 28 of 58 cases, the mothers were smokers. Serially cut sections of coronary arteries were stained for light microscopy and immunotypified for CD68, CD34, alpha-smooth muscle actin, proliferating cell nuclear antigen, c-fos and apoptosis.

RESULTS

Multifocal coronary lesions were detected in 10 of 12 fetuses and in 15 of 16 infants whose mothers smoked. Arterial lesions in infants with nonsmoking mothers were observed in only five cases (two of 10 fetuses and three of 20 infants) (P<0.001). Alterations ranged from focal areas with mild myointimal thickening in prenatal life to early soft plaques in infants. Smooth muscle cells infiltrated into the subendothelium. These early lesions demonstrated c-fos gene activation in the smooth muscle cells of the media, and in some of these, positivity for apoptosis was observed, suggesting that c-fos overexpression may promote proliferation, as evidenced by proliferating cell nuclear antigen-positive cells.

CONCLUSIONS

Early intimal alterations of the coronary arteries are detectable in the prenatal and infancy period, and may be significantly associated with maternal smoking.

Monitoring of atherosclerosis

Population-based epidemiological studies of atherosclerosis using autopsy material is now impossible to perform in most countries due to declining autopsy rates. Based on epidemiological studies of atherosclerosis using autopsy material in five European cities which were carried out with an interval of 25 years in the 1960s and 1980s, respectively, we have shown that atherosclerosis in young so-called practically healthy people, 20-39 years of age, who died from accidental causes, closely reflects the level of atherosclerosis in the population as a whole. These people can thus be used for monitoring the development of atherosclerosis in a population since they are normally a subject to a medico-legal autopsy; therefore, material for such studies can be obtained. Furthermore, histomorphological studies of specimens that are taken from practically healthy people at standard places of coronary arteries and aortas also reflect this general level of atherosclerosis. These studies also provide information on the atherosclerotic process and its relation to various risk factors.

Hyperplasia of coronary intima in young males in relation to development of coronary heart disease in adults

The aim of the investigation was to study structural features of coronary arteries in young males which may influence the development of stenosing coronary atherosclerosis in older age. We studied the coronary arteries from 84 males, 10-39 years old, who died from accidents in Moscow, Malmo and Riga, and 98 males aged 40 and above from Moscow who died from coronary heart disease (71 cases) or other diseases (27 cases). In children and young males from all three cities, musculo-elastic hyperplasia of the coronary intima took place constantly but with different degrees of expression; a strict relationship of the intimal thickness and age was observed. Histometric investigations of the right coronary artery showed that in young males of Riga, in comparison with those of Malmo, the intima was significantly thicker both outside (69.6+/-2.8 and 58. 2+/-2.5 microm) and within the area of cushion like thickening (118. 8+/-4.0 and 101.9+/-3.8 microm), they had more extended cushion-like thickening of intima (42.6+/-3.0 and 30.8+/-3.3% to the length of the artery circumference) and destroyed parts of the internal elastic lamina (28.3+/-1.9 and 19.1+/-1.7% of its length). In males older than 40 years, severe coronary atherosclerosis and stenosis was also significantly more common in Riga than in Malmo. Our data indicate that with age the intimal musculo-elastic hyperplasia in the coronary arteries is transformed to a fibro-elastic layer. The thickness of this layer in the presence of stenosing plaques (>75% of arterial lumen) was much greater than in the presence of plaques with stenoses less than 50% (188.1+/- 7.3 and 69.8+/-4.5 microm, respectively).

CONCLUSION

The development of stenosing coronary atherosclerosis is closely related to the degree of musculo-elastic intimal hyperplasia in childhood and young age. The formation of a fibro-elastic layer in the coronary intima decreases the ability of the artery to dilate during the development of atherosclerosis.

Congenital heart disease and sudden death in the young

Sudden death is a frequent mode of fatal outcome in cardiac disease and does not exclude young people. The aim of this investigation was to establish whether and to what extent sudden death in the young may be ascribable to the substrate of underlying congenital heart disease. Among 182 young people (< or = 35 years) who died of cardiac sudden death and underwent postmortem examination, 58 (32%) had congenital heart disease. Seven showed an intrapericardial rupture of aortic dissection, in the setting of Marfan syndrome in two, isolated bicuspid aortic valve in two, and bicuspid aortic valve and isthmic coarctation in three; all exhibited equally severe degeneration of the aortic wall. Sixteen cases had conduction system anomalies, mostly bypass tracts; 15 coronary artery anomalies (three ostial valve-like stenosis, five origin from the wrong aortic sinus, and seven deep intramyocardial course); 12 hypertrophic cardiomyopathy; five postoperative congenital heart disease including scar following ventriculotomy, conduction system injury, and defects left unrepaired; and three congenital aortic valve stenosis. One third of sudden deaths in the young was ascribable to structural defects present since birth. A large spectrum of congenital heart disease involves the risk of sudden death, but most structural defects are usually not considered to be life threatening. Some of these concealed defects are potentially detectable in life by clinical imaging techniques.

Sudden death in the young. Is acute coronary thrombosis the major precipitating factor?

BACKGROUND

Atherosclerotic coronary artery disease, complicated by acute thrombosis, is the usual cause of sudden death in adults. This study addresses the pathology of coronary arteries in sudden death in the young (< or = 35 years old).

METHODS AND RESULTS

Among 200 consecutive cases of sudden death in youth in the Veneto region of Italy, 37 (33 men and 4 women, age 18 to 35 years; mean, 29.4 years) showed obstructive atherosclerotic coronary artery disease in the absence of other cardiac pathological conditions and causes of death. No patient had previous angina pectoris or myocardial infarction. Cardiac arrest occurred at rest in 30 subjects and was related to effort in 7. A histological study was carried out on the obstructive coronary plaques. Degree of lumen stenosis and extension of lipid core and intimal fibrocellular hyperplasia facing the lumen were calculated morphometrically. Immunohistochemistry and electron microscopy were used to further characterize the plaque cell population. Single-vessel disease was found in 33 patients and triple-vessel disease in 4, with an overall total of 45 obstructive plaques, 34 of which were located in the proximal left anterior descending coronary artery. At histological study, only 10 plaques from 10 patients showed acute thrombosis (occlusive in 5 and subocclusive in 5); the remaining 35 were uncomplicated. Thirty-one plaques were fibrous in nature, while the other 14 were atheromatous. Compared with the atheromatous lesions, the fibrous plaques were rarely complicated by thrombosis (3% versus 64%; P < .001) and distinctly exhibited a fairly well-preserved tunica media (81% versus 21%; P < .001) as well as a stratum of neointimal fibrocellular hyperplasia (68% versus 7%; P < .001), which on immunohistochemistry and electron microscopy appeared to be proliferating smooth muscle cells.

CONCLUSIONS

In our study population, sudden death was precipitated by acute coronary thrombosis in only 27% of patients with obstructive coronary atherosclerotic plaque. Most of the young victims of sudden death with obstructive coronary atherosclerosis showed single-vessel disease that affected the left anterior descending coronary artery and was due to fibrous plaques with neointimal smooth muscle cell hyperplasia and a preserved tunica media in the absence of acute thrombosis.

Coronary arteriosclerosis in dogfish (Scyliorhinus canicula). An assessment of some potential risk factors

Coronary myointimal lesions are described in the dogfish (Scyliorhinus canicula). These lesions are similar to those previously described in salmonids and are characterized by breaks in and disappearance of the inner elastic layer and intimal thickening as a result of inclusions of fibers and smooth muscle cells. Lesions are associated with all the branching points in the main subepicardial conal coronary arteries that supply the heart. Intimal thickenings were rare in other parts of these arteries. However, we found extensive lesions unassociated with branching points in two main intramyocardial ventricular arteries that supply the ventricular spongy myocardium. We carried out a statistical study of the incidence and severity of these intramyocardial lesions in relation to several potential risk factors. Intimal thickenings were present in 90.5% of the fish specimens and 40% of the histological sections. Sex, reproductive stage, plasma triacylglycerol, and cholesterol (total and related to high-density lipoproteins) were not significantly related to either the incidence or severity of lesions. Total fish length was significantly correlated with the lesion severity index (r = 0.33, p < 0.01). We also found significant differences in incidence related to the location of lesions. The middle areas of the intramyocardial branches, very close to the atrioventricular canal, were more affected than the cranial and caudal areas. The dorsal and ventral artery walls were also more affected than the lateral ones. The preferential location of the lesions in areas presumably subjected to mechanical stress because of a bifurcating bloodstream or the pulsatile flow throughout the atrioventricular canal suggests that coronary arteriosclerosis in dogfish is an age-related process, with hemodynamic factors playing a primary or secondary pathogenetic role. This disease seems not to be related to some factors suggested for salmonids, such as reproductive cycle, anadromous migration, river pollution, or plasma lipid concentration.

Intimal thickening of the coronary arteries in infants in relation to family history of coronary artery disease

BACKGROUND

Intimal thickenings of the coronary arteries of newborn children are composed mainly of smooth muscle cell proliferations. To investigate whether thickening of the intima in infants is associated with a family history of coronary artery disease (CAD), we studied the relation of coronary death of grandparents to intimal thickening of 136 infants.

METHODS AND RESULTS

The length of internal elastic lamina of the artery and the areas of arterial layers in cross section were measured, and the arteries were transformed to idealized round circles. Intimal thickening was assessed as the degree of luminal narrowing (ratio of intimal area to the area on the luminal side of the arterial media). Among 136 infants, luminal narrowing varied between 0% and 58%. CAD deaths accounted for 108 of the total 281 deaths among the grandparents of the infants. Family history of CAD (defined as at least one CAD death among the four grandparents) was positive for 77 infants. Family history of CAD was significantly more common in the infants with luminal narrowing of both the left and right coronary arteries compared with the infants with no narrowing in at least one artery (odds ratio adjusted for sex, infection status, and age of infant, 5.69; 95% confidence interval, 1.46-22.2). After adjustment for sex and age, infants with both a positive family history and presence of infection had an increased degree of luminal narrowing compared with infants with a negative family history and no infection.

CONCLUSIONS

The association of coronary artery intimal thickening in infancy with family history of CAD suggests that intimal thickening is a morphological manifestation of predisposition to CAD.

Experimental induction of atherosclerosis associated with femoral arteriovenous fistulae in rabbits on a stock diet

Chronic femoral arteriovenous fistulae were surgically produced in stock-fed rabbits. The aortic bifurcation and branching sites of the ilio-femoral arteries from each side were examined histologically by the serial section technique in rabbits killed at varying times from 121 to 800 days postoperatively. Similar preparations were examined from old multiparous breeding does and rabbits with a control femoral arteriotomy. Tears of the internal elastic lamina were prominent in the abdominal aorta and homolateral ilio-femoral arteries of those with fistulae but were only occasional and sporadic in contralateral arteries and control animals. Intimal proliferation at branching sites proximal to the fistula exhibited varying degrees of enlargement, extension and progression to overt atherosclerosis with lipid accumulation, fibrin deposition and calcification. Such changes were minimal proximally in contralateral vessels of a few rabbits and non-existent in control material. These results (i) constitute the first experimental induction of the progression of intimal proliferation to overt atherosclerosis at branching sites in stock-fed animals and (ii) substantiate the importance of haemodynamics in atherogenesis.