Composition of atherosclerotic plaques in coronary arteries in women less than 40 years of age with fatal coronary artery disease and implications for plaque reversibility

Development of physiologically-informed computational coronary artery plaques for use in virtual imaging trials

BACKGROUND

As a leading cause of death, worldwide, cardiovascular disease is of great clinical importance. Among cardiovascular diseases, coronary artery disease (CAD) is a key contributor, and it is the attributed cause of death for 10% of all deaths annually. The prevalence of CAD is commensurate with the rise in new medical imaging technologies intended to aid in its diagnosis and treatment. The necessary clinical trials required to validate and optimize these technologies require a large cohort of carefully controlled patients, considerable time to complete, and can be prohibitively expensive. A safer, faster, less expensive alternative is using virtual imaging trials (VITs), utilizing virtual patients or phantoms combined with accurate computer models of imaging devices.

PURPOSE

In this work, we develop realistic, physiologically-informed models for coronary plaques for application in cardiac imaging VITs.

METHODS

Histology images of plaques at micron-level resolution were used to train a deep convolutional generative adversarial network (DC-GAN) to create a library of anatomically variable plaque models with clinical anatomical realism. The stability of each plaque was evaluated by finite element analysis (FEA) in which plaque components and vessels were meshed as volumes, modeled as specialized tissues, and subjected to the range of normal coronary blood pressures. To demonstrate the utility of the plaque models, we combined them with the whole-body XCAT computational phantom to perform initial simulations comparing standard energy-integrating detector (EID) CT with photon-counting detector (PCD) CT.

RESULTS

Our results show the network is capable of generating realistic, anatomically variable plaques. Our simulation results provide an initial demonstration of the utility of the generated plaque models as targets to compare different imaging devices.

CONCLUSIONS

Vast, realistic, and variable CAD pathologies can be generated to incorporate into computational phantoms for VITs. There they can serve as a known truth from which to optimize and evaluate cardiac imaging technologies quantitatively.

Sex differences in coronary plaque changes assessed by serial computed tomography angiography

Long-term data on sex-differences in coronary plaque changes over time is lacking in a low-to-intermediate risk population of stable coronary artery disease (CAD). The aim of this study was to evaluate the role of sex on long-term plaque progression and evolution of plaque composition. Furthermore, the influence of menopause on plaque progression and composition was also evaluated. Patients that underwent a coronary computed tomography angiography (CTA) were prospectively included to undergo a follow-up coronary CTA. Total and compositional plaque volumes were normalized using the vessel volume to calculate a percentage atheroma volume (PAV). To investigate the influence of menopause on plaque progression, patients were divided into two groups, under and over 55 years of age. In total, 211 patients were included in this analysis, 146 (69%) men. The mean interscan period between baseline and follow-up coronary CTA was 6.2 ± 1.4 years. Women were older, had higher HDL levels and presented more often with atypical chest pain. Men had 434 plaque sites and women 156. On a per-lesion analysis, women had less fibro-fatty PAV compared to men (β -1.3 ± 0.4%; p < 0.001), with no other significant differences. When stratifying patients by 55 years age threshold, fibro-fatty PAV remained higher in men in both age groups (p < 0.05) whilst women younger than 55 years demonstrated more regression of fibrous (β -0.8 ± 0.3% per year; p = 0.002) and non-calcified PAV (β -0.7 ± 0.3% per year; p = 0.027). In a low-to-intermediate risk population of stable CAD patients, no significant sex differences in total PAV increase over time were observed. Fibro-fatty PAV was lower in women at any age and women under 55 years demonstrated significantly greater reduction in fibrous and non-calcified PAV over time compared to age-matched men. (ClinicalTrials.gov number, NCT04448691.)

Coronary plaque tissue characterization in patients with premature coronary artery disease

Premature coronary artery disease (CAD) studies rarely involve coronary plaque characterization. We characterize coronary plaque tissue by radiofrequency intravascular ultrasound (IVUS) in patients with premature CAD. From July 2015 to December 2017, 220 patients from the Department of Cardiology, Affiliated Hangzhou First People’s Hospital, Zhejiang University School of Medicine with first occurrence of angina or myocardial infarction within 3 months were enrolled. Patients with premature CAD (n = 47, males aged < 55 years, and females aged < 65 years) or later CAD (n = 155) were retrospectively compared for cardiovascular risk factors, laboratory examination findings, coronary angiography data, gray-scale IVUS, and iMap-IVUS. The mean age was 53.53 ± 7.24 vs. 70.48 ± 8.74 years (p < 0.001). The groups were similar for traditional coronary risk factors except homocysteine (18.60 ± 5.15 vs. 17.08 ± 4.27 µmol/L, p = 0.043). After matching for baseline characteristics, LDL cholesterol (LDL-C) was higher for premature CAD than later CAD (2.50 ± 0.96 vs. 2.17 ± 0.80 mmol/L, p = 0.019). Before the matching procedure, the premature CAD group had shorter target lesion length [18.50 (12.60–32.00) vs. 27.90 (18.70–37.40) mm, p = 0.002], less plaque volume [175.59 (96.60–240.50) vs. 214.73 (139.74–330.00) mm³, p = 0.013] than the later CAD group. After the matching procedure, the premature CAD group appeared to be less plaque burden (72.69 ± 9.99 vs. 74.85 ± 9.80%, p = 0.005), and positive remodeling (1.03 ± 0.12 vs. 0.94 ± 0.18, p = 0.034), and lower high risk feature incidence (p = 0.006) than the later CAD group. At the plaque’s minimum lumen, premature CAD had more fibrotic (p < 0.001), less necrotic (p = 0.001) and less calcified areas (p = 0.012). Coronary plaque tissue was more fibrotic with less necrotic and calcified components in premature than in later CAD, and the range and degree of atherosclerosis were significantly lower.

Incidence and outcome of peri-procedural cardiogenic shock: results from the international Euro Heart Survey PCI registry

BACKGROUND

There is a large body of literature on acute myocardial infarction complicated by cardiogenic shock. However, very little is known about patients who are initially haemodynamically stable and develop cardiogenic shock during percutaneous coronary intervention.

METHODS

A total of 47,407 consecutive patients were prospectively enrolled in the PCI Registry of the Euro Heart Survey Programme. We analysed interventions with peri-procedural complications that were classified as 'shock induced by procedure' on the case report form. Clinical and procedural characteristics as well as hospital outcomes of haemodynamically stable patients who developed cardiogenic shock during percutaneous coronary intervention were evaluated. Patients with haemodynamic instability at presentation prior to intervention were excluded.

RESULTS

A total of 68 patients (0.2%) developed cardiogenic shock as a complication of percutaneous coronary intervention. The majority of cases comprised acute coronary syndrome (60.3%) with complex lesions (93.1%). Most patients had multi-vessel disease (82.1%) and an ejection fraction less than 40% (58.1%). In the multivariate analysis, left main disease (odds ratio (OR) 9.51), ST-segment elevation myocardial infarction (OR 5.31) and multi-vessel disease without left main involvement (OR 3.32) were the strongest independent predictors of peri-procedural cardiogenic shock. Among these patients procedural success was low (66.1%) and in-hospital mortality was very high (39.7%).

CONCLUSIONS

In this real-world registry the rate of haemodynamically stable patients who developed cardiogenic shock during percutaneous coronary intervention was very low. Patients at a priori high risk were more likely to be affected by this complication. The in-hospital mortality rate of these patients was very high.

Coronary artery disease in post-menopausal women: are there appropriate means of assessment?

The recognition of sex differences in cardiovascular disease, particularly the manifestations of coronary artery disease (CAD) in post-menopausal women, has introduced new challenges in not only understanding disease mechanisms but also identifying appropriate clinical means of assessing the efficacy of management strategies. For example, the majority of treatment algorithms for CAD are derived from the study of males, focus on epicardial stenoses, and inadequately account for the small intramyocardial vessel disease in women. However, newer investigational modalities, including stress perfusion cardiac magnetic resonance imaging and positron emission tomography are providing enhanced diagnostic accuracy and prognostication for women with microvascular disease. Moreover, these investigations may soon be complemented by simpler screening tools such as retinal vasculature imaging, as well as novel biomarkers (e.g. heat shock protein 27). Hence, it is vital that robust, sex-specific cardiovascular imaging modalities and biomarkers continue to be developed and are incorporated into practice guidelines that are used to manage women with CAD, as well as gauge the efficacy of any new treatment modalities. This review provides an overview of some of the sex differences in CAD and highlights emerging advances in the investigation of CAD in post-menopausal women.

Quantitative Extent of Atherosclerotic Plaque in the Major Epicardial Coronary Arteries in Patients with Fatal Coronary Heart Disease, in Coronary Endarterectomy Specimens, in Aorta-Coronary Saphenous Venous Conduits, and Means to Prevent the Plaques: A Review after Studying the Coronary Arteries for 50 Years

This review tries to answer the following 15 questions: Is atherosclerosis a systemic or a regional disease? Is atherosclerosis in any particular region focal or diffuse? What is the quantity of atherosclerotic plaques in endarterectomy specimens of the right coronary artery in patients undergoing coronary artery bypass grafting (CABG) compared to that in the right coronary artery in patients with fatal coronary artery disease? How do the units used for measuring arterial narrowing by angiography compare to the units used for measuring arterial narrowing at necropsy? What do atherosclerotic plaques consist of in coronary arteries in patients with fatal coronary disease? What is the quantity of atherosclerotic plaque in bypassed -vs- non-bypassed native coronary arteries in patients dying early (<60 days) or late (>60 days) after coronary artery bypass grafting? What is the frequency of acute coronary lesions and multi-luminal channels at necropsy in patients with unstable angina pectoris, sudden coronary death, and acute myocardial infarction? What is the mechanism of luminal widening by angioplasty in the coronary arteries? What observations suggest that atherosclerotic plaques are the result at least in part of organization of thrombi? Is atherosclerosis a multifactoral or a unifactoral disease? What characteristics distinguish carnivores and herbivores? What are reasonable guidelines for whom to treat with lipid-altering agents? What is the rule of 5 and the rule of 7 in statin therapy? What is the effect of lipid lowering drug therapy on coronary luminal narrowing? What are some requisites for a healthy life?

Oxidative status and reduced glutathione levels in premature coronary artery disease and coronary artery disease

Identifying patients at risk of developing premature coronary artery disease (PCAD) which occurs at age below 45 years old and constitutes approximately 7-10% of coronary artery disease (CAD) worldwide remains a problem. Oxidative stress has been proposed as a crucial step in the early development of PCAD. This study was conducted to determine the oxidative status of PCAD in comparison to CAD patients. PCAD (<45 years old) and CAD (>60 years old) patients were recruited with age-matched controls (n = 30, each group). DNA damage score, plasma malondialdehyde (MDA) and protein carbonyl content were measured for oxidative damage markers. Antioxidants such as erythrocyte glutathione (GSH), oxidised glutathione (GSSG), and glutathione peroxidase activity (GPx), superoxide dismutase (SOD) and catalase (CAT) were also determined. DNA damage score and protein carbonyl content were significantly higher in both PCAD and CAD when compared to age-matched controls while MDA level was increased only in PCAD (p<.05). In contrast, GSH, GSH/GSSG ratio, α-tocotrienol isomer, and GPx activity were significantly decreased, but only in PCAD when compared to age-matched controls. The decrease in GSH was associated with PCAD (OR = 0.569 95%CI [0.375 - 0.864], p = .008) and cut-off values of 6.69 μM with areas under the ROC curves (AUROC) 95%CI: 0.88 [0.80-0.96] (sensitivity of 83.3%; specificity of 80%). However, there were no significant differences in SOD and CAT activities in all groups. A higher level of oxidative stress indicated by elevated MDA levels and low levels of GSH, α-tocotrienol and GPx activity in patients below 45 years old may play a role in the development of PCAD and has potential as biomarkers for PCAD.

A Comparative Study of Coronary Atherosclerosis in Young and Old

INTRODUCTION

Atherosclerotic coronary artery disease is an important cause of sudden and unexpected deaths in the young people. It is assumed that thrombosis and plaque hemorrhage are commonly associated with sudden deaths from coronary atherosclerosis in the young. In this study, we compared the histological patterns of atherosclerosis in young and old populations to see whether an association exists between the histological pattern of atherosclerosis in the young and thrombosis or plaque hemorrhage.

METHODS AND RESULTS

All autopsy cases of coronary atherosclerosis in young people (aged younger than 40 years) in comparison with an equal number of randomly selected older people (older than 65 years) over a period of 4 and a half years in the Provincial Forensic Pathology Unit of the Ontario Forensic Pathology Service in Toronto, Canada, were reviewed to characterize the gross and histologic appearance. There were 28 cases of atherosclerosis in young people ("the young"). Twenty-three (82%) of the young had eccentric atherosclerosis compared with 11 (39%) of the old. An inflammatory response was seen in all 28 (100%) of the young in comparison with 17 (61%) of the old. Thirteen (47%) of the young compared with 3 (11%) of the old had thrombosis, whereas 9 (32%) of the young and 17 (61%) of the old had plaque hemorrhage. Pultaceous debris was the principal component in 11 atherosclerotic plaques (39%) in the young, followed by foam cells in 7 (25%). In the older group, pultaceous debris was the principal component in 18 (64%) followed by dense fibrous tissue in 5 (18%).

CONCLUSIONS

The morphology in coronary atherosclerosis of the young is significantly different from the old. Coronary atherosclerosis in the young commonly shows an eccentric distribution with associated inflammation. Thrombosis is commoner among the young, whereas plaque hemorrhage is commoner among the old.

Assessment of atherosclerosis in chronic granulomatous disease

BACKGROUND

Patients with chronic granulomatous disease (CGD) experience immunodeficiency because of defects in the phagocyte NADPH oxidase and the concomitant reduction in reactive oxygen intermediates. This may result in a reduction in atherosclerotic injury.

METHODS AND RESULTS

We prospectively assessed the prevalence of cardiovascular risk factors, biomarkers of inflammation and neutrophil activation, and the presence of magnetic resonance imaging and computed tomography quantified subclinical atherosclerosis in the carotid and coronary arteries of 41 patients with CGD and 25 healthy controls in the same age range. Univariable and multivariable associations among risk factors, inflammatory markers, and atherosclerosis burden were assessed. Patients with CGD had significant elevations in traditional risk factors and inflammatory markers compared with control subjects, including hypertension, high-sensitivity C-reactive protein, oxidized low-density lipoprotein, and low high-density lipoprotein. Despite this, patients with CGD had a 22% lower internal carotid artery wall volume compared with control subjects (361.3±76.4 mm(3) versus 463.5±104.7 mm(3); P<0.001). This difference was comparable in p47(phox)- and gp91(phox)-deficient subtypes of CGD and independent of risk factors in multivariate regression analysis. In contrast, the prevalence of coronary arterial calcification was similar between patients with CGD and control subjects (14.6%, CGD; 6.3%, controls; P=0.39).

CONCLUSIONS

The observation by magnetic resonance imaging and computerized tomography of reduced carotid but not coronary artery atherosclerosis in patients with CGD despite the high prevalence of traditional risk factors raises questions about the role of NADPH oxidase in the pathogenesis of clinically significant atherosclerosis. Additional high-resolution studies in multiple vascular beds are required to address the therapeutic potential of NADPH oxidase inhibition in cardiovascular diseases.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: NCT01063309.

Is hard tissue formation in the dental pulp after the death of the primary odontoblasts a regenerative or a reparative process?

OBJECTIVES

Conceptually, two types of tertiary dentine may be produced in response to caries and environmental irritations: "reactionary dentine" that is secreted by existing primary odontoblasts and "reparative dentine", formed after the death of the odontoblasts by proliferation and differentiation of progenitor cells into odontoblast-like cells. Because histologic evidence for tubular dentine generated by newly differentiated odontoblast-like cells is lacking in human teeth, the present study examined pulpal cellular changes associated with caries/restorations, in the presence or absence of pulpal exposures.

METHODS

Ninety-six extracted human teeth were histologically processed and serial sectioned for light microscopy: 65 contained untreated enamel/dentine caries; 20 were heavily restored and 11 had carious exposures managed by direct pulp-capping.

RESULTS

Sparsely distributed, irregularly arranged dentinal tubules were identified from the tertiary dentine formed in teeth with unexposed medium/deep caries and in restored teeth; those tubules were continuous with the tubules of secondary dentine; in some cases, tubules were absent. The palisade odontoblast layer was reduced to a single layer of flattened cells. In direct pulp-capping of pulp exposures, the defects were repaired by the deposition of an amorphous dystrophic calcified tissue that resembled pulp stones more than dentine, sometimes entrapping pulpal remnants. This atubular hard tissue was lined by fibroblasts and collagen fibrils.

CONCLUSIONS

Histological evidence from the present study indicates that reparative dentinogenesis cannot be considered as a regenerative process since the so-formed hard tissue lacks tubular features characteristic of genuine dentine. Rather, this process represents a repair response that produces calcified scar tissues by pulpal fibroblasts.

CLINICAL SIGNIFICANCE

Formation of hard tissue in the dental pulp after the death of the primary odontoblasts has often been regarded by clinicians as regeneration of dentine. If the objective of the clinical procedures involved is to induce healing, reduce dentine hypersensitivity, or minimise future bacteria exposure, such procedures may be regarded as clinical success. However, current clinical treatment procedures are not adept at regenerating physiological dentne because the tissues formed in the dental pulp are more likely the result of repair responses via the formation of calcified scar tissues.

Attenuated predictive power of a normal myocardial perfusion scan in young smokers

BACKGROUND

The negative predictive value of a normal myocardial perfusion image (MPI) for myocardial infarction or cardiac death is very high. However, it is unclear whether a normal MPI, reflecting non-compromised blood flow in the stable state, would have the same prognostic implications in smokers as in patients who do not smoke.

METHODS

The incidence of total mortality, cardiovascular mortality, and myocardial infarction was evaluated in 11,812 subjects (14.6% of whom were current smokers at the time of the study) with a normal MPI study and no past history of coronary artery disease during the period 1997 to 2008.

RESULTS

During an average follow-up of 72.4 ± 32.4 months the risk for an acute myocardial infarction in current smokers was approximately 50% higher than the corresponding risk in non-smokers, despite a younger average age. Cox proportional regression models show that current smoking was associated with an increased hazard rate for the composite endpoint below age 60 (HR=2.09, 95%CI 1.43-3.07, p<0.001), but not at older ages (HR=1.16, 95% CI 0.81-1.66, p=0.4).

CONCLUSIONS

In individuals below age 60, but not at older ages, current smoking is associated with increased short- and long-term risk of cardiac death and acute myocardial infarction even in subjects with a normal MPI.

Ultrasound-assessed non-culprit and culprit coronary vessels differ by age and gender

AIM: To investigate age- and gender-related differences in non-culprit versus culprit coronary vessels assessed with virtual histology intravascular ultrasound (VH-IVUS).

METHODS: In 390 patients referred for coronary angiography to a single center (Luzerner Kantonsspital, Switzerland) between May 2007 and January 2011, 691 proximal vessel segments in left anterior descending, circumflex and/or right coronary arteries were imaged by VH-IVUS. Plaque burden and plaque composition (fibrous, fibro-fatty, necrotic core and dense calcium volumes) were analyzed in 3 age tertiles, according to gender and separated for vessels containing non-culprit or culprit lesions. To classify as vessel containing a culprit lesion, the patient had to present with an acute coronary syndrome, and the VH-IVUS had to be performed in a vessel segment containing the culprit lesion according to conventional coronary angiography.

RESULTS: In non-culprit vessels the plaque burden increased significantly with aging (in men from 37% ± 12% in the lowest to 46% ± 10% in the highest age tertile, P < 0.001; in women from 30% ± 9% to 40% ± 11%, P < 0.001); men had higher plaque burden than women at any age (P < 0.001 for each of the 3 age tertiles). In culprit vessels of the lowest age tertile, plaque burden was significantly higher than that in non-culprit vessels (in men 48% ± 6%, P < 0.001 as compared to non-culprit vessels; in women 44% ± 18%, P = 0.004 as compared to non-culprit vessels). Plaque burden of culprit vessels did not significantly change during aging (plaque burden in men of the highest age tertile 51% ± 9%, P = 0.523 as compared to lowest age tertile; in women of the highest age tertile 49% ± 8%, P = 0.449 as compared to lowest age tertile). In men, plaque morphology of culprit vessels became increasingly rupture-prone during aging (increasing percentages of necrotic core and dense calcium), whereas plaque morphology in non-culprit vessels was less rupture-prone and remained constant during aging. In women, necrotic core in non-culprit vessels was very low at young age, but increased during aging resulting in a plaque morphology that was very similar to men. Plaque morphology in culprit vessels of young women and men was similar.

CONCLUSION: This study provides evidence that age- and gender-related differences in plaque burden and plaque composition significantly depend on whether the vessel contained a non-culprit or culprit lesion.

Noninvasive assessment of gender differences in coronary plaque composition with multidetector computed tomographic angiography

To date, sparse data are available with regard to gender differences in plaque morphology and composition. The aim of the present report was to assess the differences in coronary plaque burden and composition in a noninvasive manner between women and men using multidetector computed tomographic angiography. The study population consisted of 416 patients (61 +/- 13 years), with 148 women (36%). A stenosis of >or=70% in at least one coronary segment was found in 11% of women compared to 25% of men (p <0.0001). Overall, women presented with a significantly lower mean number of segments containing calcified plaques (1.43 +/- 2.04 vs 2.25 +/- 2.30, p = 0.004) and mixed plaques (1.67 +/- 1.23 vs 2.25 +/- 2.30, p = 0.05). No such relation was seen with noncalcified plaques (0.72 +/- 1.01 vs 0.86 +/- 1.06, p = 0.21). In addition, the assessment of the overall proportion of the composition of plaque burden revealed relatively more noncalcified (40% vs 28%), less calcified (38% vs 43%), and mixed (23% vs 28%) plaques in women than in men (p <0.0001). On multivariate analysis of the total plaque burden, the women had a 19% (95% confidence interval 11% to 28%, p <0.0001) greater relative distribution of plaque that was noncalcified compared to the men, and the overall plaque burden was less likely to be calcified (p = 0.006) or mixed (p = 0.019). Similar results were seen in younger and older subjects. In conclusion, gender differences exist, not only in the atherosclerotic disease burden, but also in the underlying plaque composition. Women tended to have more exclusively noncalcified plaque and were less likely to have calcified or mixed plaques compared to men. Future studies are needed to elucidate whether these underlying differences in plaque composition might explain the reduced risk of cardiac events in women.

Sudden coronary death caused by pathologic intimal thickening without atheromatous plaque formation

BACKGROUND

Atherosclerotic plaques progress from early lesions with little free cholesterol and lipid to late fibroatheromas with necrotic cores that may rupture. The frequency of severe coronary atherosclerosis without core formation in any artery in sudden coronary death is not known.

METHODS

We studied 314 hearts from 253 men and 61 women who died suddenly from severe coronary stenosis (≥ 1 epicardial artery with ≥ 75% luminal area narrowing) and with no other cause of death. If no section demonstrated any necrotic core, the designation was nonatheromatous atherosclerosis; if there was ≥ 1 necrotic core, the designation was atheromatous atherosclerosis. Plaques were scored for the presence of calcification, intimal inflammation, and neovasculature on a 5-point scale. Plaque burden was estimated semiquantitatively.

RESULTS

In 22 men (9%) and 14 women (23%), there were no necrotic cores in any plaque (nonatheromatous atherosclerosis). Fourteen of these 36 nonatheromatous atherosclerosis cases had focal acute thrombus due to erosion (39%). Of the remaining 278 cases (atheromatous atherosclerosis), acute erosions were present in 25 (9%; P<.0001). Sudden death due to nonatheromatous atherosclerosis occurred more frequently in women (P<.001), in Blacks (20%; P=.003), and at a younger age (44± 12 years) than atheromatous atherosclerosis (52 ± 12 years; P=.0003). On multivariate analysis, nonatheromatous atherosclerosis was associated with younger age (P=.001), female gender (P=.004), and Black race (P=.006).

CONCLUSIONS

Nonatheromatous atherosclerosis constitutes slightly >10% of sudden coronary deaths and is more frequent in young Black women. Nonatheromatous atherosclerosis is a relatively infrequent pathway for coronary plaque progression, leading to severe disease and sudden death that may involve plaque erosion.

Impact of gender and age on in vivo virtual histology-intravascular ultrasound imaging plaque characterization (from the global Virtual Histology Intravascular Ultrasound [VH-IVUS] registry)

Virtual histology intravascular ultrasound (VH-IVUS) analyses were performed in the first 990 patients enrolled in the 3,000+ patient global VH-IVUS Registry to assess the impact of gender and age on in vivo VH-IVUS plaque characterization. The 990 patients were divided into 3 age group terciles (<58, 58 to 68, and >68 years) and again divided according to gender. In conclusion, (1) both women and men had an increase in plaque with increasing age; (2) at any age, men had more plaque than women; (3) percentages of dense calcium and necrotic core increased with increasing patient age in both men and women; and (4) gender differences were lowest in the oldest tercile (>68 years).

Age-related alteration of risk profile, inflammatory response, and angiographic findings in patients with acute coronary syndrome

Background:

Coronary artery disease (CAD) is a major public health problem which in turn imposes a significant burden on health care systems because of high morbidity and mortality. Although the multifactorial etiology of CAD increases with age, but in recent years, the incidence is increasing among younger age groups.

Objectives:

In this study we aimed to evaluate the effect of age on risk profile, inflammatory response and the angiographic findings in patients with ACS.

Patients and Methods:

The study comprised 253 ACS patients. Seventy six (30%) with UA, 56 (22%) with NSTEMI and 121(48%) with STEMI diagnosis. The value of Hs-CRP, lipid profile, cardiac enzymes, risk factors, EF% and angiographic score were analyzed and compared in different age groups.

Results:

Group 1 (n = 68) with age <45 years, group II (n = 110) with age ≥45–<65 years and group III (n = 75) ≥65 years. Group I had more prevalence of male sex, smoking, family history, hypertriglyceridemia and low levels of HDL (P < 0.01), higher incidence of STEMI (P < 0.01) and lower prevalence of UA (P < 0.01). Diabetes mellitus, hypertension, and female gender were more common in older groups. Hs-CRP was significantly lower in the young age (group I). Group I showed a preponderance of single-vessel disease, lower coronary atherosclerotic score and prevalent left anterior descending artery (LAD) involvement compared with older age groups. Hs-CRP was positively correlated to severity of CAD only in older groups. Stepwise multiple regression analysis showed that age, male gender, cardiac enzymes and EF% were common predictors of multivessel disease. Smoking was independent predictor in young patients <45 years while diabetes and Hs-CRP was the key predictor in older patient groups.

Conclusion:

Young patients with ACS had different clinical, angiographic and biochemical profile. Hs-CRP peak concentration did not correlate with angiographic findings in young patients that could be attributed to different risk profile and discrete underlying mechanism.

Age-dependent changes in oxygen tension, radiation dose and sensitivity within normal and diseased coronary arteries-Part A: dose from radon and thoron

PURPOSE

There is mounting evidence that a significant fraction of radiation-induced mortality and years-life lost are non-cancerous in nature. This study quantifies the radon dose to the coronary artery walls, especially the intimal layer, vulnerable to the development of atherosclerosis, and associated cardiovascular disease (CVD). Two accompanying papers determine the oxygen levels (Part B) in coronary arteries and the oxygen effect for radon and other exposures (Part C).

MATERIALS AND METHODS

The alpha-radiation dose to coronary artery walls was calculated from the proportion of inhaled radon ((222)Rn), thoron ((220)Rn) and their short-lived progeny, which was not deposited in the lung and passed into blood. Age- and gender-dependent morphology and composition for the wall layers of coronary arteries were developed from published data for a normal population and also for individuals with cardiovascular disease. The alpha particle dose to the coronary artery walls was evaluated taking account the diffusion of radon from blood and the solubility of radon-gas in tissues.

RESULTS

Diseased arteries exhibited a moderate increase in the solubility of lipophylic radon (190%) in arteries with 88% luminal narrowing, as the high Rn solubility in fat was partially offset by the lower solubility in calcium deposits. The average worldwide dose rate to the diseased intimal layer from (222)Rn and its short-lived progeny was estimated to be as high as 68 muSv y(-1) per 40 Bq m(-3) in air, whereas the corresponding dose rate from (220)Rn per 0.3 Bq m(-3) in air was <or=0.1% in comparison. Gender had little influence on the dose.

CONCLUSION

The Rn dose to the coronary arteries is significant, but has a large uncertainty due to poor knowledge of Rn and its progeny concentrations in the body.

LDL-cholesterol lowering or HDL-cholesterol raising for cardiovascular prevention

A number of reports have indicated that both lowering low density lipoprotein (LDL)-cholesterol and raising high density lipoprotein (HDL)-cholesterol can result in significant cardiovascular benefit, both in terms of reduction of events and also, to a variable extent, of atheromatous lesions. LDL and HDL have opposite roles in body cholesterol regulation and, in theory, both reduced deposition (LDL reduction) and increased removal (raised HDL) can improve vascular disease. A number of reports over the last 30 years have attempted to quantitate with cholesterol balance/turnover studies, the correlations between LDL and HDL levels and body cholesterol pool sizes. More recently, these studies have evaluated the effects of LDL or HDL changes on cholesterol elimination. Data have, at times, been fully consistent with theoretical expectations, whereas at others they have not. Evaluation of these, at times, historical data provides, however, an important clue to the understanding of current results with different medications for the management of lipoprotein disorders.

Therapeutic use of the high-density lipoprotein protein and peptides

High-density lipoprotein (HDL) therapy is a novel and emerging area of therapeutic development in the cardiovascular field. It attempts to supplement and improve the vascular benefit exerted by other agents that are active on lipid metabolism, for example, hypolipidaemic drugs. Furthermore, it takes advantage of the novel techniques of coronary evaluation. A number of reports have examined the potential therapeutic properties of the synthetic HDLs prepared by complexing recombinant apolipoprotein (apo) A-I(Milano), a variant form of native apoA-I, with phospholipids. The availability of synthetic HDL complexes containing recombinant apoA-I(Milano) has opened up a new era of therapeutic management for coronary disease. HDL formulations of recombinant apoA-I(Milano)-phospholipid complexes have clearly shown rapid regression of a focal carotid atheroma as well as powerful protection from myocardial infarction in a rabbit model. In a pilot study, ETC-216 showed a significant reduction in coronary plaque burden after five weekly treatments, assessed by intravascular ultrasound in patients with acute coronary syndrome. Other therapeutic options of HDL therapy have recently became available.

Perspectives on Dyslipidemia and Coronary Heart Disease in Women

Coronary heart disease (CHD) remains the leading cause of death among American women. Numerous differences exist between younger and older women and between women and men with respect to the pathology of CHD and its incidence and prevalence over the life cycle. Differences in lipoprotein levels and lipid fractions play an important role in CHD risk. Hormonal influences on lipoprotein levels in women are complex, change throughout the life span, and are influenced by the administration of oral contraceptives and hormone replacement therapy. Women with obesity, metabolic syndrome, or diabetes have lipid profiles that adversely affect CHD risk. To date, no randomized trials testing the impact of lifestyle changes on lipoprotein levels and subsequent CHD events in non-institutionalized women have been performed, and women have not been well represented in clinical end point trials of pharmacologic lipid-lowering therapy. Available evidence suggests that lipid-lowering therapy with statins does provide benefit in reducing the risk of coronary events in women; however, women remain undertreated, and more data are needed to determine optimal cardiovascular prevention and treatment in this population.

The role of estrogen in cardiovascular disease

Cardiovascular disease is the number one cause of death among women, accounting for nearly 50% of female deaths. Statistics show that women on average develop cardiovascular disease 10 to 15 years later in life than men, and that the risk may increase after menopause. This observation has led to much speculation as to what physiological change(s) associated with menopause is responsible for the higher risk of atherosclerosis. Estrogen, with its potential as a cardioprotective agent and as an immunomodulator of the inflammatory response in atherosclerosis, has received the most attention. Understanding the mechanisms that lead to these differences may allow beneficial therapeutic intervention to enhance this effect in females and evoke this protection in males. This review will do the following: (1) characterize mechanisms of atherosclerosis, (2) explore the role of estrogen-replacement therapy, (3) define the effect of gender on inflammation, (4) compare and contrast the effects of estrogen and testosterone on endothelial functional, and (5) suggest mechanistic based therapeutic opportunities.

What is the cardioprotective role of hormone replacement therapy?

A very large body of literature has yielded strong biologic and mechanistic plausibility for the consistent observational findings that estrogen is cardioprotective. Recently completed randomized, controlled trials have been interpreted as challenging the doctrine that hormone replacement is cardioprotective for postmenopausal women. However, other than the Estrogen in the Prevention of Atherosclerosis Trial, none of the currently completed (and no ongoing) randomized, controlled trials have appropriately tested the hypothesis generated from observational data that estrogen replacement is cardioprotective. This mainly results from the fact that randomized, controlled trials have not tested the same pattern and type of hormone use in the same population of women observed in the epidemiologic studies. On the other hand, recently completed randomized, controlled trials provide important but limited information concerning the clinical use of a specific regimen of hormone replacement for the prevention of cardiovascular disease in a particular population of postmenopausal women. Observations made from epidemiologic studies will have to be appropriately tested in randomized, controlled trials before any real conclusions can be drawn as to whether hormone replacement is cardioprotective.

Postmenopausal hormone replacement therapy and atherosclerosis

The role of postmenopausal hormone replacement therapy (HRT) in the prevention of cardiovascular disease (CVD) has evolved since estrogen was first proposed to be vasoprotective. The discovery of novel molecular signaling pathways involving the estrogen receptor in vascular cells and the elucidation of numerous biologic mechanisms have suggested that HRT may exert its potentially beneficial or adverse cardiovascular effects through multiple mechanisms. Estrogen has genomic, as well as rapid nongenomic, effects that alter vasodilation, coagulation, inflammation, and the vascular injury response, some of which may have potentially beneficial or adverse cardiovascular consequences. Current guidelines do not support the use of HRT in the secondary prevention of CVD, and recent results of primary prevention trials show evidence of increased early cardiovascular risk and no overall health benefit with combination estrogen-progestin treatment. The role of estrogen alone in the primary prevention of CVD awaits the results of ongoing trials. The key to the use of estrogen replacement therapy for the prevention of CVD may be to target therapy before atherosclerosis is evident, and to identify women with genetic susceptibility who may be at increased risk for an adverse outcome associated with therapy.

Quantitative evaluation of carotid atherosclerotic plaques by magnetic resonance imaging

In order to study human atherosclerotic plaque burden and composition in vivo, an imaging technique is needed that can directly measure volume and characterize the cross-sectional morphologic components of the atherosclerotic arterial wall. High-resolution magnetic resonance imaging (MRI), which is noninvasive and nonirradiative, has been described as one promising modality to achieve these purposes. MRI allows direct visualization of the diseased vessel wall and is capable of characterizing the morphology of individual atherosclerotic carotid plaques.

Antiatherosclerosis interventions in women

Although important in reducing atherosclerosis progression and cardiovascular events in women, lowering of low-density lipoprotein cholesterol levels is not sufficient for optimum prevention. Additional potential targets for intervention include reducing levels of triglyceride-rich lipoproteins, increasing high-density lipoprotein cholesterol, and replacing certain hormones that decrease during menopause. Hormone replacement therapy (HRT) for the reduction of atherosclerosis progression and cardiovascular events has become complicated because of conflicting outcomes from recent surrogate end point studies and secondary prevention randomized clinical trials. The key to HRT may be early intervention, when women first enter menopause and the atherosclerotic process appears to be relatively quiescent. Although many questions remain to be answered in this important area of women's health, there is a fact that is certain: administration of HRT for the reduction of cardiovascular events is not a straightforward proposition. Powerful imaging tools for monitoring atherosclerosis progression exist that can be used to help address many questions relating to type, dose, regimen, and timing of HRT.

Atherosclerosis imaging methods: assessing cardiovascular disease and evaluating the role of estrogen in the prevention of atherosclerosis

Various interventions for cardiovascular disease (CVD) slow or reverse the progression of atherosclerosis and reduce the risk of clinical coronary events. Although the cardiovascular benefits of hormone replacement therapy have been demonstrated in observational studies in predominantly healthy women, no benefit has been found in a randomized clinical trial conducted in older women with established CVD. It is possible that the benefit of hormone therapy occurs when it is used relatively early in the progression of atherosclerosis. Techniques are now available to monitor the various stages of atherosclerosis. Quantitative coronary angiography, a technique used to evaluate relatively late-stage atherosclerosis, has been shown to predict the risk of subsequent clinical coronary events. B-mode ultrasonography of the intima-media wall thickness (IMT) of the carotid artery can assess the earlier stages of atherosclerosis and correlates with atherosclerosis risk factors, as well as with clinical cardiovascular and cerebrovascular outcome. This technique offers a relatively rapid and cost-effective method to test therapies for CVD and to screen for individuals who are at high risk for cardiovascular events. As an example of the use of atherosclerosis imaging to evaluate possible therapeutic interventions, measurements of IMT were performed in a randomized, controlled trial comparing oral 17beta-estradiol with placebo. The results demonstrated that 17beta-estradiol significantly reduces the progression of subclinical atherosclerosis in healthy, postmenopausal women when compared with placebo.

Accelerated atherosclerosis in saphenous vein bypass grafts: a spectrum of diffuse plaque instability

Our understanding of plaque instability may be extended to vein graft atherosclerosis, which appears to represent the end of a continuum of plaque instability. Compared with plaque in native coronary arteries, vein graft atheroma is more diffuse and vulnerable to rupture, and the consequences of plaque rupture in vein grafts seem to be associated with almost certain thrombotic occlusion within 7 to 12 years after surgery.

Postmenopausal hormone replacement therapy as antiatherosclerotic therapy

Cardiovascular disease remains the number one killer of women. Although important for the reduction of cardiovascular events, lipid alteration does not appear to be sufficient to obtain optimum reduction in cardiovascular risk. Women have a potential opportunity for further reduction in cardiovascular risk through postmenopausal hormone replacement therapy. More than 50 observational studies indicate that postmenopausal use of hormone replacement therapy reduces atherosclerosis and cardiovascular events. However, recently reported, randomized, controlled clinical trials have yielded mixed results as to whether hormone replacement therapy reduces cardiovascular events relative to placebo. These, as well as other randomized controlled trials of hormone replacement therapy and cardiovascular disease in postmenopausal women, are reviewed. Although conclusions concerning the specific hormones used in the specific populations studied can be offered from the completed trials, more broad conclusions concerning the use of hormone replacement therapy in the prevention of cardiovascular disease will have to await conduction and completion of other trials.

Effects of prolonged intensive lipid-lowering therapy on the characteristics of carotid atherosclerotic plaques in vivo by MRI: a case-control study

High-resolution magnetic resonance imaging (MRI) with flow suppression not only provides useful information on luminal and wall areas of the carotid artery but also can identify the principal tissue components of the carotid atherosclerotic plaque. The effects of intensive lipid-lowering therapy on these MRI tissue characteristics were examined in patients with coronary disease (CAD). Eight CAD patients who have been receiving intensive lipid-lowering treatment (niacin 2.5 g/d, lovastatin 40 mg/d, and colestipol 20 g/d) for 10 years in the Familial Atherosclerosis Treatment Study (FATS) follow-up were randomly selected from among 60 such treated patients. Eight CAD patients who were matched to the treated patients for age (+/-3 years), baseline low density lipoprotein (+/-5 mg/dL), and triglycerides (+/-50 mg/dL) but who had never been treated with lipid-lowering drugs were selected as controls. For each of these 32 carotid arteries, luminal and plaque areas were measured by planimetry, in a blinded protocol, from the magnetic resonance image that showed most plaque. Fibrous tissue, calcium, and lipid deposits were identified on the basis of established criteria. Plaque composition was estimated as a fraction of total planimetered area. Patients treated with 10-year intensive lipid-lowering therapy, compared with control subjects, had significantly lower low density lipoprotein cholesterol levels (84 versus 158 mg/dL, respectively; P<0.001) and higher high density lipoprotein cholesterol levels (51 versus 37 mg/dL, respectively; P<0.001). As a group, treated patients, compared with untreated control subjects, had a smaller core lipid area (0.7 versus 10.2 mm(2), respectively; P=0.01) and lipid composition (1% versus 17%, respectively). Group differences in luminal area (55 [treated] versus 44 [control] mm(2), P=NS) and plaque area (58 [treated] versus 64 [control] mm(2), P=NS) tended to favor treatment. MRI appears useful for estimating carotid plaque size and composition. Hyperlipidemic CAD patients frequently (97%) have at least moderate (>/=40% area stenosis) carotid plaque. In this case-control study, prolonged intensive lipid-lowering therapy is associated with a markedly decreased lipid content, a characteristic of clinically stable plaques.

Effect of menopause on plaque morphologic characteristics in coronary atherosclerosis

BACKGROUND

Coronary artery disease in women appears 10 to 15 years later than in men. To test the hypothesis that the effects of estrogen may manifest themselves as histologic differences in coronary plaques, we examined the hearts of premenopausal and postmenopausal women who died suddenly from coronary artery disease.

METHODS

We studied 51 cases of sudden coronary death and 47 deaths in women who died from noncoronary causes. Coronary deaths were classified on the basis of histologic features. The number of acute plaque ruptures, healed plaque ruptures, vulnerable plaques, and acute plaque erosions were compared between groups. Postmortem values of serum total cholesterol, HDL cholesterol, and thiocyanate were measured, and menopausal status was confirmed by calculating body mass index.

RESULTS

Women older than 50 years of age were much more likely to have a ruptured plaque than were younger, premenopausal women. Plaque rupture was significantly associated with elevated total cholesterol level. In the 51 women who died of coronary disease, the mean number of vulnerable plaques increased significantly as women advanced into the postmenopausal years.

CONCLUSIONS

Our data suggest that estrogen has an anti-inflammatory effect on atherosclerotic plaques, resulting in plaque stabilization. Plaque erosion, the major substrate for thrombosis in premenopausal women, does not appear to be inhibited by estrogen. Because plaque progression may result both from repeated rupture and repeated erosion, a better understanding of the effect of estrogen on atherosclerosis may yield insights into the nature of coronary artery disease.

Sex differences in morphology of coronary artery plaque assessed by intravascular ultrasound

BACKGROUND

Results of autopsy studies have suggested that there are sex differences in morphology of coronary-artery plaques, but these differences have yet to be adequately evaluated in vivo.

DESIGN AND METHODS

We performed preintervention intravascular ultrasound (IVUS) measurements on coronary plaques in a consecutive series of 76 men and 30 women with unstable angina pectoris. Both the target lesion and an adjacent reference site were evaluated. Arterial, plaque, and luminal areas were measured by planimetry. Plaques were classified as either calcified or uncalcified, and relative density of plaque was quantitatively assessed by videodensitometry, using a linear gray scale normalized with respect to density of adventitia.

RESULTS

Although women were older than men (mean age 55.0 +/- 10.9 versus 60.4 +/- 12.2 years, P = 0.02), their target lesions were less dense (74.6 +/- 23.4 versus 86.2 +/- 22.2% of adventitial density, P = 0.02) and less often found to be calcified (20.0 versus 38.2%, P = 0.05). Similarly, reference sites in female subjects were less dense (77.6 +/- 15.3 versus 97.1 +/- 19.4% of adventitial density, P = 0.01). There was no sex difference in the severity of coronary stenosis.

CONCLUSIONS

Both qualitative and quantitative sex differences in in-vivo morphology of coronary plaques morphology were detected by IVUS measurement. Plaques in women appear less videodense and are less often calcified than are those in men. Future studies employing sequential IVUS examinations are needed in order to determine whether these morphologic differences relate to a delay in initiation of plaques, slower progression of plaques, or other sex-specific modulators of plaque composition.

Effect of risk factors on the mechanism of acute thrombosis and sudden coronary death in women

BACKGROUND

Traditional risk factors have been linked to atherosclerotic heart disease in women. However, the effect of risk factors and menopausal status on the mechanism of sudden coronary death is unknown.

METHODS AND RESULTS

We examined 51 cases of sudden coronary death and 15 hearts from women who died of trauma. Coronary deaths were divided into four mechanisms of death: ruptured plaque with acute thrombus (n = 8), eroded plaque with acute thrombus (n = 18), stable plaque with healed infarct (n = 18), and stable plaque without infarction (n = 7). Vulnerable plaques prone to rupture were defined as those with a thin, fibrous cap infiltrated by macrophages and were quantitated in coronary deaths and control subjects. Total cholesterol (TC), HDL cholesterol, glycosylated hemoglobin, cigarette smoking, and hypertension were determined in each case. Compared with control subjects, women with plaque ruptures had elevated TC (270 +/- 55 versus 194 +/- 44 mg/dL, P = 0.002), and those with erosions were more likely to be smokers (78% versus 33%, P = 0.01). Women with stable plaque and healed infarct had elevated glycosylated hemoglobin (10.2 +/- 5.0% versus 6.4 +/- 0.4% in control subjects, P = 0.001) and were more likely to be hypertensive (50% versus 15% in control subjects, P = 0.03). By multivariate analysis, cigarette smoking was associated with plaque erosion (P = 0.03, odds ratio [OR] 21), glycoslyated hemoglobin with stable plaque and healed infarct (P = 0.03, OR 41), TC with plaque rupture (P = 0.02, OR 7), and hypertension with stable plaque with healed infarct (P = 0.02, OR 15). Seven of 8 plaque ruptures occurred in women > 50 years of age versus 3 of 18 erosions (P = 0.001). In cases of coronary death, vulnerable plaques were associated with elevated cholesterol (P = 0.002) and age > 50 years (P = 0.002), independent of other risk factors.

CONCLUSIONS

In women, traditional risk factors have distinct effects on the mechanisms of sudden coronary death, which vary by menopausal status. Effective risk factor modification may therefore differ between younger and older women and may be targeting different mechanisms of plaque instability.

Predictors of coronary arterial remodeling patterns in patients with myocardial ischemia

Preangioplasty intravascular ultrasound in 81 patients showed that adaptive remodeling occurred in 35% and constrictive remodeling in 34%. Multivariate analysis showed that smoking and fibrocalcific plaques were associated with constrictive remodeling, whereas small vessel size and hypercholesterolemia were associated with adaptive remodeling.

Coronary plaque erosion without rupture into a lipid core. A frequent cause of coronary thrombosis in sudden coronary death

BACKGROUND

Coronary thrombosis has been reported to occur most frequently in lipid-rich plaques with rupture of a thin fibrous cap and contact of the thrombus with a pool of extracellular lipid. However, the frequency of coronary artery thrombosis with or without fibrous cap rupture in sudden coronary death is unknown. In this study, we compared the incidence and morphological characteristics of coronary thrombosis associated with plaque rupture versus thrombosis in eroded plaques without rupture.

METHODS AND RESULTS

Fifty consecutive cases of sudden death due to coronary artery thrombosis were studied by histology and immunohistochemistry. Plaque rupture of a fibrous cap with communication of the thrombus with a lipid pool was identified in 28 cases. Thrombi without rupture were present in 22 cases, all of which had superficial erosion of a proteoglycan-rich plaque. The mean age at death was 53 +/- 10 years in plaque rupture cases versus 44 +/- 7 years in eroded plaques without rupture (P < .02). In the plaque-rupture group, 5 of 28 (18%) were women versus 11 of 22 (50%) with eroded plaques (P = .03). The mean percent luminal area stenosis was 78 +/- 12% in plaque rupture and 70 +/- 11% in superficial erosion (P < .03). Plaque calcification was present in 69% of ruptures versus 23% of erosions (P < .002). In plaque ruptures, the fibrous cap was infiltrated by macrophages in 100% and T cells in 75% of cases compared with 50% (P < .0001) and 32% (P < .004), respectively, in superficial erosions. Clusters of smooth muscle cells adjacent to the thrombi were present in 95% of erosions versus 33% of ruptures (P < .0001). HLA-DR expression was more often seen in macrophages and T cells in ruptures (25 of 28 cases) compared with expression in macrophages in superficial erosion arteries (8 of 22 cases, P = .0002).

CONCLUSIONS

Erosion of proteoglycan-rich and smooth muscle cell-rich plaques lacking a superficial lipid core or plaque rupture is a frequent finding in sudden death due to coronary thrombosis, comprising 44% of cases in the present study. These lesions are more often seen in younger individuals and women, have less luminal narrowing and less calcification, and less often have foci of macrophages and T cells compared with plaque ruptures.

Rapid angiographic progression of coronary artery disease in patients with angina pectoris. The role of complex stenosis morphology

BACKGROUND

Rapid disease progression commonly underlies acute coronary events, and "complex" stenosis morphology may play a role in this phenomenon.

METHODS AND RESULTS

We studied the role of complex stenosis morphology in rapid disease progression in 94 consecutive patients awaiting routine coronary angioplasty. Coronary arteriography was repeated at 8 +/- 3 months' follow-up, immediately preceding angioplasty (68 patients) or after an acute coronary event (26 patients). Disease progression of 217 stenoses, of which 79 (36%) were "complex" and 138 (64%) were "smooth," was assessed by computerized angiography. At presentation, 63 patients had stable angina pectoris and 31 had unstable angina that settled rapidly with medical therapy. At follow-up, 23 patients (24%) had progression of preexisting stenoses and 71 (76%) had no progression. Patients with progression were younger (55 +/- 12 years) than those without (58 +/- 9 years) but did not differ with regard to risk factors, previous myocardial infarction, or severity and extent of coronary disease. Twenty-three lesions (11%) progressed, 15 to total occlusion (11 complex and 4 smooth; 65%). Progression occurred in 17 of the 79 complex stenoses (22%) and in 6 of the 138 smooth lesions (4%) (P = .002). Mean stenosis diameter reduction was also significantly greater in complex than in smooth lesions (11.6% versus 3.9% change; P < .001). Acute coronary events occurred in 57% of patients with progression compared with 18% of those without progression (P < .001) and were more frequent in patients who presented with unstable angina (P = .002).

CONCLUSIONS

Rapid stenosis progression is not uncommon, and complex stenoses are at risk more than smooth lesions.

Clinical factors and angiographic features associated with premature coronary artery disease

BACKGROUND

Clinical, angiographic, and biochemical features may differ in young patients with coronary heart disease compared with older patients.

METHODS

We compared clinical and angiographic characteristics in 100 male patients with clinical onset of disease at age < or = 45 years (group 1) with those of 100 older male patients (clinical onset of disease at > or = 60 years) (group 2). All patients had documented coronary artery disease. The two patient groups were compared in terms of the pattern of angina at disease onset, angiographic features, and coronary risk factors.

RESULTS

Seventy-six patients in group 1 and 49 patients in group 2 presented with acute coronary syndromes (unstable angina or myocardial infarction) at clinical disease onset (p < 0.001). Compared with patients in group 2, younger patients (group 1) showed a preponderance of single-vessel disease (54 vs 36%; p < 0.001) and complex stenosis morphologic features (59 vs 36%; p < 0.01). Family history of coronary artery disease (39 vs 11%; p < 0.001) and smoking (73 vs 46%; p < 0.001) were also more prevalent in younger patients. Mean plasma total cholesterol level was 6.4 +/- 1.3 mmol/L in group 1 and 6.1 +/- 1.2 mmol/L in group 2 (p = NS). Younger patients, however, had lower high-density lipoprotein (HDL) cholesterol (0.9 +/- 0.2 mmol/L and 1.1 +/- 0.4 mmol/L; p < 0.01) and higher plasma triglyceride levels compared with patients of group 2 (2.7 +/- 1.3 mmol/L vs 2.1 +/- 1.1 mmol/L; p < 0.001).

CONCLUSIONS

Patients with premature coronary disease referred to coronary angiography commonly have unheralded acute onset of symptoms, angiographically complex stenosis morphologic features, and less extensive coronary artery disease. In addition to previously identified risk factors such as family history and smoking, we observed that high plasma triglyceride and low HDL cholesterol levels are associated with premature coronary artery disease.

Identification of patients at high risk for adverse coronary events while awaiting routine coronary angioplasty

BACKGROUND

Identification of patients at risk for progression of coronary stenosis and adverse clinical events while awaiting coronary angioplasty is desirable.

OBJECTIVE

To determine the standard clinical or angiographic variables, or both, present at initial angiography associated with the development of adverse coronary events (unstable angina, myocardial infarction, and angiographic total coronary occlusion) in patients awaiting routine percutaneous transluminal coronary angioplasty (PTCA).

PATIENTS AND METHODS

Consecutive male patients on a waiting list for routine PTCA. Routine clinical details were obtained at initial angiography. Stenosis severity was measured using computerised angiography.

OUTCOME MEASURES

Development of one or more of myocardial infarction, unstable angina, or angiographic total coronary occlusion while awaiting PTCA were recorded as an adverse event.

RESULTS

Some 214 of 219 patients underwent a second angiogram. One had a fatal myocardial infarction and four (2%) were lost to follow up. Fifty patients (23%) developed one or more adverse events (myocardial infarction five, unstable angina 35, total coronary occlusion 23) at a median (range) interval of 8 (3-25) months. Twenty (57%) of the 35 patients with unstable angina developed adverse events compared with 30 (17%) of the 180 with stable angina (P = 0.0001). Plasma triglyceride concentration was 2.6 (1.2) mmol/l in patients with adverse coronary events compared with 2.2 (1.1) mmol/l in those without such events (P < 0.05). Patients with adverse events were younger than those without (54 (9) years v 58 (9) years, P < 0.01). The relative risk of an adverse event in patients with unstable angina and increased plasma triglyceride concentrations was 6.9 compared with those presenting with stable angina and a normal triglyceride concentration (P < 0.02).

CONCLUSIONS

The study shows that adverse events are not uncommon in patients awaiting PTCA. Patients at high risk for adverse events may be predicted by the presence of acute coronary syndrome, increased concentration of plasma triglyceride, and younger age at the time of the first angiogram.

Geometric remodeling is not the principal pathogenetic process in restenosis after balloon angioplasty. Evidence from correlative angiographic-histomorphometric studies of atherosclerotic arteries in rabbits

BACKGROUND

Restenosis after balloon angioplasty of coronary arteries is thought to be a proliferative response of the arterial wall to injury. Recently, it has been suggested that geometric remodeling of the arterial wall, rather than intimal fibromuscular hyperplasia, may be the major pathophysiological mechanism underlying restenosis. In this study, we evaluated the relative contribution of a geometric decrease in arterial size versus neointimal growth to luminal narrowing associated with restenosis after balloon angioplasty of atherosclerotic femoral arteries in rabbits.

METHODS AND RESULTS

Focal femoral atherosclerosis was induced by endothelial desiccation injury followed by a 2% cholesterol diet. After 1 month on the high cholesterol diet, the animals were subjected to one of four strategies: (1) balloon angioplasty, (2) balloon angioplasty followed by treatment with the factor Xa inhibitor antistasin, (3) combined laser and balloon angioplasty, or (4) no angioplasty. Animals were killed 2 hours or 28 days after angioplasty, and excised femoral artery segments were prepared for histomorphometric analysis. Angiography was performed serially before and immediately after angioplasty and before the animals were killed. An initial postprocedural gain in luminal diameter at sites of angioplasty was followed by a significant reduction in diameter by angiography and a significant increase in luminal cross-sectional area narrowing by plaque by histomorphometry 28 days after angioplasty compared to adjacent nonangioplastied segments of the same arteries, to nonangioplastied control arteries, or to angioplastied segments of animals treated with the factor Xa inhibitor antistasin. By contrast, the overall arterial size (cross-sectional area bounded by the external elastic lamina) at sites of restenosis was not significantly different from adjacent nonangioplastied segments in the majority of arteries excised at 28 days, and the mean overall arterial size at sites of restenosis was not significantly different from corresponding segments of nonangioplastied control arteries or from angioplastied segments of animals treated with antistasin. In the minority of angioplastied arteries in which the arterial size did change, most got larger.

CONCLUSIONS

Geometric remodeling resulting in a decrease in overall cross-sectional arterial size does not appear to be the principal pathogenetic mechanism for restenosis after balloon angioplasty with or without laser in this experimental model.