Coronary artery calcium scanning in asymptomatic patients with diabetes mellitus: A paradigm shift

Coronary artery calcium (CAC) is the most powerful cardiac risk prognosticator in the asymptomatic population, with consistent superiority to all risk factor‐based paradigms. More recently, the strong prognostic value of changes in CAC has been demonstrated. The application of CAC to asymptomatic patients with diabetes mellitus (DM), all of whom have been presumed to be of high risk, has yielded a range of risks from low to high, proportional to the amount of calcified plaque, as in patients without DM. These risks are higher than in non‐diabetic patients at corresponding CAC levels, except for those without CAC who have the same low risk as non‐diabetic patients. In addition, the value of serial scanning to assess plaque progression and prognosis in people with DM has been demonstrated. Therefore, we propose that: (i) DM is not a coronary artery disease equivalent; (ii) CAC can be used routinely in all asymptomatic diabetic patients >40 years of age, as proposed by American College of Cardiology/American heart Association guidelines; and (iii) serial CAC scanning be considered for evaluation of the response to therapy.     

Performance of the coronary calcium score in an outpatient chest pain clinic and strategies for risk stratification

BackgroundCoronary artery calcium score (CAC) is an objective marker of atherosclerosis. The primary aim is to assess CAC as a risk classifier in stable coronary artery disease (CAD).HypothesisCAC improves CAD risk prediction, compared to conventional risk scoring, even in the absence of cardiovascular risk factor inputs.MethodsOutpatients presenting to a cardiology clinic (n = 3518) were divided into two cohorts: derivation (n = 2344 patients) and validation (n = 1174 patients). Adding logarithmic transformation of CAC, we built two logistic regression models: Model 1 with chest pain history and risk factors and Model 2 including chest pain history only without risk factors simulating patients with undiagnosed comorbidities. The CAD I Consortium Score (CCS) was the conventional reference risk score used. The primary outcome was the presence of coronary artery disease defined as any epicardial artery stenosis≥50% on CT coronary angiogram.ResultsArea under curve (AUC) of CCS in our validation cohort was 0.80. The AUC of Models 1 and 2 were significantly improved at 0.88 (95%CI 0.86–0.91) and 0.87 (95%CI 0.84–0.90), respectively. Integrated discriminant improvement was >15% for both models. At a pre‐specified cut‐off of ≤10% for excluding coronary artery disease, the sensitivity and specificity were 89.3% and 74.7% for Model 1, and 88.1% and 71.8% for Model 2.ConclusionCAC helps improve risk classification in patients with chest pain, even in the absence of prior risk factor screening.     

Coronary artery calcium by digital cinefluoroscopy in patients with pain suggestive of an acute coronary syndrome

BACKGROUND: Detection of coronary calcium may be a useful noninvasive approach for detecting coronary artery disease (CAD) in subjects presenting to the emergency department with chest pain. HYPOTHESIS: We tried to assess the diagnostic value of coronary artery calcium (CAC) detection by digital cinefluoroscopy in patients with new-onset chest pain suggestive of an acute coronary syndrome. METHODS: In 97 consecutive patients (70 men, 27 women, mean standard deviation [SD] age 55 (11) and 60 (8) years, respectively), with new-onset chest pain suggestive of an acute coronary syndrome, nondiagnostic electrocardiogram, and normal initial creatine kinase (CK)-MB, digital cinefluoroscopy was performed for CAC detection. RESULTS: All patients underwent routine clinical evaluation with treadmill exercise test, thallium scintigraphy, dobutamine stress echocardiography, and coronary angiography, as needed clinically and blinded to the cinefluoroscopy results. Coronary artery calcium was present in 27 of 33 (81.8%) of patients with and in 10 of 64 (15.6%) of patients without CAD, p < 0.0001. The presence of CAC had 82% sensitivity, 84% specificity, 73% positive predictive value, and 90% negative predictive value for CAD diagnosis (odds ratio = 24.3, 95% confidence interval 7.98-73.94). CONCLUSIONS: In patients with acute chest pain, nondiagnostic electrocardiogram and normal initial enzyme evaluation, CAC detection by digital cinefluoroscopy appears to have high sensitivity, specificity, and negative predictive value for CAD diagnosis.     

Is acoustic shadowing at intracoronary ultrasound always the marker of intramural calcium accumulation?

Intracoronary ultrasound (ICUS) is increasingly used at catheterization to assess more precisely the severity of luminal narrowing, to delineate the composition of the atherosclerotic plaque, and to select the optimal therapeutic strategy. With this technique, a drop in signal intensity, known as acoustic shadowing, is usually equated with the presence of calcium in the plaque. We report the study of an atherosclerotic coronary artery showing intense acoustic shadowing at ICUS, but in which no calcium deposition could be evidenced at postmortem pathological analysis. This observation suggests a word of caution with regard to considering acoustic shadowing at ICUS as the reflection of superficial calcium deposition within a vessel wall. © 1995 Wiley-Liss, Inc.     

Telomeres and atherosclerosis

Abstract

In humans and other multicellular organisms that have an extended lifespan, the leading causes of death are atherosclerotic cardiovascular disease and cancer. Experimental and clinical evidence indicates that these age-related disorders are linked through dysregulation of telomere homeostasis. Telomeres are DNA protein structures located at the terminal end of chromosomes and shorten with each cycle of cell replication, thereby reflecting the biological age of an organism. Critically shortened telomeres provoke cellular senescence and apoptosis, impairing the function and viability of a cell. The endothelial cells within atherosclerotic plaques have been shown to display features of cellular senescence. Studies have consistently demonstrated an association between shortened telomere length and coronary artery disease (CAD).Several of the CAD risk factors and particularly type 2 diabetes are linked to telomere shortening and cellular senescence. Our interest in telomere biology was prompted by the high incidence of premature CAD and diabetes in a subset of our population, and the hypothesis that these conditions are premature-ageing syndromes. The assessment of telomere length may serve as a better predictor of cardiovascular risk and mortality than currently available risk markers, and anti-senescence therapy targeting the telomere complex is emerging as a new strategy in the treatment of atherosclerosis. We review the evidence linking telomere biology to atherosclerosis and discuss methods to preserve telomere length.     

The pulsatile component of blood pressure: its role in the pathogenesis of atherosclerosis

Pulse pressure (PP) is traditionally believed to increase cardiovascular risk because of an increase in afterload leading to left ventricular hypertrophy. It has also been emphasized that low diastolic blood pressure, being in part responsible for high PP, leads to an impairment of myocardial perfusion with all its adverse consequences. More recently, however, a direct role of pulsatile blood pressure changes in the pathogenesis of atherosclerosis and its complications has become better known. Experimental studies indicate that there is a cause-and-effect type of relationship between the pulsatile component of blood pressure and atherosclerotic process. A significant relationship between the parameters of the pulsatile blood pressure component and the extent of coronary atherosclerosis was also demonstrated. Currently the presence of a bidirectional link between atherosclerosis and PP is commonly postulated, meaning that an increased PP may be both a cause and an effect of atherosclerosis. This may result in a vicious circle wherein the pulsatile blood pressure component induces/enhances the development of atherosclerosis, which in its turn reduces the arterial compliance and enhances pulse wave reflection, thereby leading to an increase in PP. Currently new drug classes are being investigated, which might reduce the pulsatile blood pressure component without changing mean blood pressure level. Their clinical usefulness should become known over the next few years.     

Peripheral atherosclerosis evaluation through ultrasound: A promising diagnostic tool for coronary artery disease

Effective treatment, but also proper diagnosis of cardiovascular diseases, remains a major challenge in everyday practice. A quick, safe, and economically acceptable non-invasive procedure should play a leading role in cardiovascular risk assessment before invasive diagnostics is performed. The staging of subclinical atherosclerosis may help in further clinical decisions. Safe, widely available, and relatively inexpensive, ultrasonography is a promising examination that should find wider application in clinical practice. The latest ESC guidelines emphasize the usefulness of carotid ultrasound in the diagnosis of coronary artery disease (CAD) and subclinical assessment of atherosclerosis, which help to determine the level of cardiovascular risk. Ultrasound examination of peripheral arteries, especially superficial vessels such as the femoral arteries, is quite easy, quick, and accurate. Other vascular beds, such as iliac and renal, are more demanding to examine, but can also provide valuable information. This review summarizes important studies comparing the severity of atherosclerosis in ultrasound-visible vascular beds in patients with established CAD. We especially emphasize the benefits of the combined assessment of atherosclerosis features, which were characterized by high sensitivity and specificity in the diagnosis of CAD and other serious cardiovascular diseases.     

尿微量白蛋白与冠状动脉粥样硬化程度相关

目的了解存在多重心血管危险因素的人群中尿微量白蛋白（MA）与冠状动脉粥样硬化程度的关系。方法共入选患者208名,平均年龄为（65.4±10.6）岁,其中高血压患者149人（71.6%）,冠心病患者125人（60.1%）。进行回顾性横断面研究,入选因怀疑或为排除冠心病而行冠脉造影的患者,并排除大量蛋白尿的患者。于静息状态下留取随机尿标本测白蛋白和肌酐,并计算二者之比值（ACR）,ACR〉30mg/g且〈300mg/g判断为MA阳性。并采用修正的Gensini评分系统评价冠脉粥样硬化的严重程度。结果尿MA阳性和阴性组在年龄、性别、收缩压、糖化血红蛋白（HbA1c）、高敏C-反应蛋白（hsCRP）上的差别具有显著性。冠脉病变程度不同的患者间性别、年龄、高血压、糖尿病、高密度脂蛋白胆固醇（HDL-C）、空腹血糖、餐后2-h血糖、HbA1c、hsCRP、ACR、血管紧张素转换酶抑制剂/血管紧张素受体拮抗剂及他汀类的使用差别有显著性。相关分析发现ACR与Gensini评分间呈显著正相关（r=0.232,P=0.001）。以Gensini评分为因变量,性别、年龄、吸烟、高血压、体重指数、腰臀比、LDL-C、HDL-C、HbA1c、hsCRP、ACR为自变量建立多元逐步线性回归模型,显示性别、ACR、LDL-C为Gensini评分的独立预测因子（B值分别为-25.0,0.3,9.2;P值分别为0.002,0.006,0.041）。结论MA与冠状动脉粥样硬化病变程度呈正相关,ACR、性别、LDL-C均为Gensini评分的独立预测因子。     

Role of calcium channel blocking agents in the prevention of atherosclerosis

Calcium channel blocking agents, although effective and widely used in the symptomatic therapy of hypertension and ischemic heart disease, have an uncertain effect on the development of coronary atherosclerosis, plaque rupture, and postrupture thrombosis. Both nifedipine and nicardipine have been shown to prevent the development of new coronary lesions but not the progression of existing lesions in prospective randomized angiographic studies. Verapamil, in contrast, failed to prevent the development of new coronary lesions and had no significant effect on the progression of existing lesions. Diltiazem, although not studied in patients with coronary atheroscleroses, has been shown to prevent the development of post-transplant coronary vascular disease. Despite the beneficial effects of nifedipine and nicardipine on new coronary lesion development, they have not been shown to reduce the incidence of recurrent ischemic events or mortality in the prospective randomized studies that demonstrated their effect on new coronary lesion development. A relatively new dihydropyridine calcium channel blocking agent, amlodipine, is hypothesized to prevent atherosclerosis due to its calcium channel blocking properties as well as by mechanisms independent of its calcium channel blocking properties. This agent has been selected for evaluation in the Prospective Randomized Evaluation of the Vascular Effects of Norvasc Trial (PREVENT) to explore whether the use of amlodipine over 3 years will reduce the incidence of early atherosclerotic lesions and, possibly, the progression of existing lesions in both the coronary and carotid arterial beds. Amlodipine could play an important future role in the secondary prevention of ischemic heart disease, but further study and a demonstration of a beneficial effect on recurrent ischemic events is required before any final conclusions concerning its effectiveness are reached.     

阿托伐他汀钙抗颈动脉粥样硬化及稳定斑块的作用

目的探讨阿托伐他汀钙对脑血管病患者的抗动脉粥样硬化及稳定斑块的作用。方法选择缺血性脑血管病患者100例,均经颈动脉超声证实其颈动脉内有斑块形成。给予阿司匹林(商品名,拜阿司匹林)0.1g/d。在此基础上,分为阿托伐他汀钙组(治疗组)50例,服用阿托伐他汀钙20mg/d,持续6个月;对照组50例,未给予阿托伐他汀钙治疗。分别于治疗前、治疗后3和6个月检测血脂,用颈动脉超声检测患者的双侧颈动脉内-中膜厚度(IMT)、斑块形态等指标。结果①治疗组服药3个月时,低密度脂蛋白胆固醇(LDL-C)和三酰甘油(TG)分别为(3.1±0.8)和(1.1±0.8)mmol/L,与对照组[(3.4±0.8)和(1.7±0.7)mmol/L]同时间点比较,差异有统计学意义(P<0.05,P<0.01);治疗组和对照组服药6个月时,总胆固醇(TC)为(4.3±0.9)、(5.6±0.8)mmol/L、LDL-L为(3.0±0.5)、(3.4±0.8)mmol/L、高密度脂蛋白胆固醇(HDL-C)为(1.1±0.2)、(1.0±0.3)mmol/L及TG为(1.1±0.9)、(1.6±0.3)mmol/L,两组同时间点比较,差异均有统计学意义(均P<0.05)。②治疗组和对照组6个月时,IMT分别为1.0±0.4和1.1±0.2,Crouse斑块积分分别为1.0±0.6和1.1±0.5,两组比较,差异有统计学意义(均P<0.05)。结论服用阿托伐他汀钙在短期内即可起到降脂作用,服药6个月以上可减轻缺血性脑血管病患者颈动脉粥样硬化程度,同时能够稳定斑块。     

冠状动脉0钙化积分人群非钙化性斑块的发生率及其危险因素分析简

目的 利用计算机断层扫描（computerized tomography,CT）冠状动脉成像,研究冠状动脉0钙化积分人群非钙化性斑块的发生率及管腔狭窄程度,并分析其相关危险因素.方法 对968例冠状动脉0钙化积分患者的影像学资料和临床资料进行回顾性分析,所有患者均行64层螺旋CT冠状动脉钙化积分扫描及CT冠状动脉成像检查;采用单因素分析和Logistic回归分析冠状动脉非钙化性斑块形成的相关危险因素.结果 968例患者中,203例（21.0％）检出非钙化性斑块,斑块导致轻度狭窄124例（61.1％）、中度狭窄53例（26.1％）、重度狭窄26例（12.8％）.Logistic回归分析显示原发性高血压（高血压）（OR=3.994,P=0.010）、男性（OR=2.663,P=0.000）、吸烟史（OR=1.376,P=0.001）、甘油三酯增高（OR=3.536,P=0.000）、高密度脂蛋白胆固醇降低（OR=0.653,P=0.008）为冠状动脉非钙化性斑块形成的危险因素.糖尿病史、血清甘油三酯和高密度脂蛋白胆固醇浓度与斑块导致的管腔狭窄程度有关.结论 冠状动脉0钙化积分人群中有相当比例的人存在非钙化性斑块,高血压、高脂血症为非钙化性斑块形成的两大独立危险因素.     

Coronary artery calcium score:Re-evaluation of its predictive value for coronary artery disease

Coronary artery disease is the leading cause of death in advanced countries and its prevalence is increasing among the developing countries.Cardiac computed tomography(CT) has been increasingly used in the diagnosis of coronary artery disease due to its rapid improvements in multislice CT scanners over the last decade,and this less-invasive technique has become a potentially effective alternative to invasive coronary angiography.Quantifying the amount of coronary artery calcium with cardiac CT has been widely accepted as a reliable non-invasive technique for predicting risk of future cardiovascular events.However,the main question that remains uncertain is whether routine,widespread coronary artery calcium scoring in an individual patient will result in an overall improvement in quality of care and clinical outcomes.In this commentary,we discuss a current issue of the clinical value of coronary artery calcium scoring with regard to its value of predicting adverse cardiac events.We also discuss the applications of coronary artery calcium scores in patients with different risk groups.     

伴有慢性支气管炎症老年患者颈动脉硬化病变与冠状动脉病变有相关性

目的:应用多普勒超声分析伴有慢性支气管炎的心绞痛患者颈动脉病变,并分析与冠心病病变的相关性。方法: 选择因心绞痛行冠状动脉造影的患者328例,根据造影结果分为对照组80例、单支病变组102例、2支病变组62例和多支病变组84例。测量颈总动脉内膜中层厚度（IMT）及颈动脉分叉处IMT,记录颈动脉斑块的位置、数量。结果: 颈总动脉IMT、分叉部IMT、斑块积分组间差异有统计学意义（P<0.05,P<0.01）。颈总动脉 IMT多支病变组与对照组（P<0.01）、2支病变组与对照组（P<0.05）、单支病变组与多支病变组（P<0.01）差异有统计学意义,其余组间两两比较无统计学差异。分叉部IMT,单支病变组与对照组差异无统计学意义,其余各组两两之间比较均有统计学差异(P<0.01,P<0.05)。斑块积分,多支病变组与2支病变组间差异无统计学意义,其余组间两两比较均有统计学差异(P<0.01,P<0.05)。颈动脉IMT、分叉部IMT、斑块积分相关系数均有统计学意义（P<0.05）。结论: 伴有慢性支气管炎的老年颈动脉粥样硬化与其冠状动脉病变有相关性。     

Association of ambulatory blood pressure variability with coronary artery calcium

Blood pressure (BP) variability is associated with progression to clinical atherosclerosis. The evidence is inconclusive if BP variability predicts cardiovascular outcomes in low‐risk populations. The aim of this study was to analyze the association of 24‐hour BP variability with coronary artery calcium (CAC) among a group of individuals without coronary artery disease. The Masked Hypertension Study targeted patients with borderline high BP (120?149 mm Hg systolic and/or 80‐95 mm Hg diastolic). Ambulatory blood pressure monitoring (ABPM) was performed at two time‐points, 8 days apart. CAC was measured at exit visit via cardiac CT and reported as Agatston Score. Weighted standard deviations and average real variability were calculated from ABPM. Of the 322 participants who underwent cardiac CT, 26% (84) had CAC present, 52% (168) were female, and 21% (64) were black. BP variability did not differ by CAC group. In this low cardiovascular risk group, CAC was not associated with 24‐hour ambulatory BP variability.