Integrating Active Learning and Transfer Learning for Carotid Intima-Media Thickness Video Interpretation.

Cardiovascular disease (CVD) is the number one killer in the USA, yet it is largely preventable (World Health Organization 2011). To prevent CVD, carotid intima-media thickness (CIMT) imaging, a noninvasive ultrasonography method, has proven to be clinically valuable in identifying at-risk persons before adverse events. Researchers are developing systems to automate CIMT video interpretation based on deep learning, but such efforts are impeded by the lack of large annotated CIMT video datasets. CIMT video annotation is not only tedious, laborious, and time consuming, but also demanding of costly, specialty-oriented knowledge and skills, which are not easily accessible. To dramatically reduce the cost of CIMT video annotation, this paper makes three main contributions. Our first contribution is a new concept, called Annotation Unit (AU), which simplifies the entire CIMT video annotation process down to six simple mouse clicks. Our second contribution is a new algorithm, called AFT (active fine-tuning), which naturally integrates active learning and transfer learning (fine-tuning) into a single framework. AFT starts directly with a pre-trained convolutional neural network (CNN), focuses on selecting the most informative and representative AU s from the unannotated pool for annotation, and then fine-tunes the CNN by incorporating newly annotated AU s in each iteration to enhance the CNN's performance gradually. Our third contribution is a systematic evaluation, which shows that, in comparison with the state-of-the-art method (Tajbakhsh et al., IEEE Trans Med Imaging 35(5):1299-1312, 2016), our method can cut the annotation cost by >81% relative to their training from scratch and >50% relative to their random selection. This performance is attributed to the several advantages derived from the advanced active, continuous learning capability of our AFT method.

Convolutional Neural Networks for Medical Image Analysis: Full Training or Fine Tuning?

Training a deep convolutional neural network (CNN) from scratch is difficult because it requires a large amount of labeled training data and a great deal of expertise to ensure proper convergence. A promising alternative is to fine-tune a CNN that has been pre-trained using, for instance, a large set of labeled natural images. However, the substantial differences between natural and medical images may advise against such knowledge transfer. In this paper, we seek to answer the following central question in the context of medical image analysis: Can the use of pre-trained deep CNNs with sufficient fine-tuning eliminate the need for training a deep CNN from scratch? To address this question, we considered four distinct medical imaging applications in three specialties (radiology, cardiology, and gastroenterology) involving classification, detection, and segmentation from three different imaging modalities, and investigated how the performance of deep CNNs trained from scratch compared with the pre-trained CNNs fine-tuned in a layer-wise manner. Our experiments consistently demonstrated that 1) the use of a pre-trained CNN with adequate fine-tuning outperformed or, in the worst case, performed as well as a CNN trained from scratch; 2) fine-tuned CNNs were more robust to the size of training sets than CNNs trained from scratch; 3) neither shallow tuning nor deep tuning was the optimal choice for a particular application; and 4) our layer-wise fine-tuning scheme could offer a practical way to reach the best performance for the application at hand based on the amount of available data.

Risk Stratification for Cardiovascular Disease in Women in the Primary Care Setting.

BACKGROUND: Traditional risk assessment tools classify the majority of middle-aged women at low risk despite cardiovascular (CV) disease's affecting >50% of women and remaining the leading cause of death. Ultrasound-determined carotid intima-media thickness (CIMT) and/or computed tomographic coronary artery calcium score (CACS) quantify subclinical atherosclerosis and add incremental prognostic value. The aim of this study was to assess the utility of CIMT and CACS to detect subclinical atherosclerosis in younger women. METHODS: Asymptomatic women aged 50 to 65 years with at least one CV risk factor and low Framingham risk scores were identified prospectively at primary care and cardiology clinics. Mean intimal thickness, plaque on CIMT, and Agatston calcium score for CACS were obtained. RESULTS: Of 86 women (mean age, 58 ± 4.6 years; mean Framingham risk score, 1.9 ± 1.2; mean low-density lipoprotein cholesterol level, 138.9 ± 37.0 mg/dL), 53 (62%) had high-risk CIMT (51% plaque, 11% CIMT > 75th percentile). In contrast, three women (3.5%) had CACS > 100, all of whom had plaque by CIMT. Of the 58 women with CACS of 0, 32 (55%) had high-risk CIMT (48% plaque, 7% CIMT > 75th percentile). CONCLUSIONS: In patients referred by their physicians for assessment of CV risk, CIMT in asymptomatic middle-aged women with at least one CV risk factor and low risk by the Framingham risk score identified a large number with advanced subclinical atherosclerosis despite low CACS. Our results suggest that CIMT may be a more sensitive method for CV risk assessment than CACS or traditional risk tools in this population. Further studies are needed to determine if earlier detection would be of clinical benefit.

A perspective on the New American College of Cardiology/American Heart Association guidelines for cardiovascular risk assessment.

The recently published American College of Cardiology (ACC)/American Heart Association (AHA) guidelines for cardiovascular risk assessment provide equations to estimate the 10-year and lifetime atherosclerotic cardiovascular disease (ASCVD) risk in African Americans and non-Hispanic whites, include stroke as an adverse cardiovascular outcome, and emphasize shared decision making. The guidelines provide a valuable framework that can be adapted on the basis of clinical judgment and individual/institutional expertise. In this review, we provide a perspective on the new guidelines, highlighting what is new, what is controversial, and potential adaptations. We recommend obtaining family history of ASCVD at the time of estimating ASCVD risk and consideration of imaging to assess subclinical disease burden in patients at intermediate risk. In addition to the adjuncts for ASCVD risk estimation recommended in the guidelines, measures that may be useful in refining risk estimates include carotid ultrasonography, aortic pulse wave velocity, and serum lipoprotein(a) levels. Finally, we stress the need for research efforts to improve assessment of ASCVD risk given the suboptimal performance of available risk algorithms and suggest potential future directions in this regard.

A summary and critical assessment of the 2013 ACC/AHA guideline on the treatment of blood cholesterol to reduce atherosclerotic cardiovascular disease risk in adults: filling the gaps.

The American College of Cardiology/American Heart Association (ACC/AHA) Task Force on Practice Guidelines has recently released the new cholesterol treatment guideline. This update was based on a systematic review of the evidence and replaces the previous guidelines from 2002 that were widely accepted and implemented in clinical practice. The new cholesterol treatment guideline emphasizes matching the intensity of statin treatment to the level of atherosclerotic cardiovascular disease (ASCVD) risk and replaces the old paradigm of pursuing low-density lipoprotein cholesterol targets. The new guideline also emphasizes the primacy of the evidence base for statin therapy for ASCVD risk reduction and lists several patient groups that will not benefit from statin treatment despite their high cardiovascular risk, such as those with heart failure (New York Heart Association class II-IV) and patients undergoing hemodialysis. The guideline has been received with mixed reviews and significant controversy. Because of the evidence-based nature of the guideline, there is room for several questions and uncertainties on when and how to use lipid-lowering therapy in clinical practice. The goal of the Mayo Clinic Task Force in the assessment, interpretation, and expansion of the ACC/AHA cholesterol treatment guideline is to address gaps in information and some of the controversial aspects of the newly released cholesterol management guideline using additional sources of evidence and expert opinion as needed to guide clinicians on key aspects of ASCVD risk reduction.

Two cases of apical ballooning syndrome masking apical hypertrophic cardiomyopathy.

Apical akinesis and dilation in the absence of obstructive coronary artery disease is a typical feature of stress-induced (takotsubo) cardiomyopathy, whereas apical hypertrophy is seen in apical-variant hypertrophic cardiomyopathy. We report the cases of 2 patients who presented with takotsubo cardiomyopathy and were subsequently found to have apical-variant hypertrophic cardiomyopathy, after the apical ballooning from the takotsubo cardiomyopathy had resolved. The first patient, a 43-year-old woman with a history of alcohol abuse, presented with shortness of breath, electrocardiographic and echocardiographic features consistent with takotsubo cardiomyopathy, and no significant coronary artery disease. An echocardiogram 2 weeks later revealed a normal left ventricular ejection fraction and newly apparent apical hypertrophy. The 2nd patient, a 70-year-old woman with pancreatitis, presented with chest pain, apical akinesis, and a left ventricular ejection fraction of 0.39, consistent with takotsubo cardiomyopathy. One month later, her left ventricular ejection fraction was normal; however, hypertrophy of the left ventricular apex was newly noted. To our knowledge, these are the first reported cases in which apical-variant hypertrophic cardiomyopathy was masked by apical ballooning from stress-induced cardiomyopathy.

Echocardiographic measures of myocardial deformation by speckle-tracking technologies: the need for standardization?

BACKGROUND: Multiple vendor-specific two-dimensional speckle-tracking echocardiographic algorithms with which to characterize myocardial mechanics are commercially available. The purpose of this study was to compare global longitudinal strain (GLS) results between two independent software vendors using a neutral image platform. METHODS: A convenience sample of 100 prospectively collected patients was evaluated. Subjects with more than two left ventricular endocardial segments poorly delineated were excluded. GLS was obtained from the apical four-chamber, three-chamber, and two-chamber views using two independent speckle-tracking echocardiographic software packages (EchoInsight version 1.5.0 and Image-Arena version 4.5). Linear regression analysis and paired t tests were used to compare GLS results. Intraclass correlation coefficients and Bland-Altman plots were used for assessments of reliability. RESULTS: The "out-of-the-box" mean GLS was -12.99 ± 2.38% using EchoInsight and -16.87 ± 2.84% using Image-Arena (mean difference, 3.87 ± 2.42%; P = .0001). Agreement between the software packages was moderate (intraclass correlation coefficient, 0.43; 95% confidence interval, 0.32-0.55). Using uniform variables to derive GLS (Lagrangian strain measured in systole and diastole at the endocardium and averaging the peak segmental strain curves), EchoInsight GLS was -16.17 ± 2.90% and Image-Arena GLS was -16.87 ± 2.84% (mean difference, 0.70 ± 2.75%; P = .02), with an intraclass correlation coefficient of 0.70 (95% confidence interval, 0.52-0.79). CONCLUSIONS: Image-Arena GLS results were consistently different (more negative) than EchoInsight measures out of the box but became similar when information used to derive GLS was uniform. The evolution of measures of myocardial mechanics into routine clinical practice will require vigilance and standardization of the various techniques, necessitating independent validation of commercially available speckle-tracking echocardiographic products.

Carotid intimal-medial thickness in active professional American football players aged 23 to 35 years.

Risk of cardiovascular disease and death in retired professional American football players may be higher than that in the general population. Previously published data have demonstrated that American football players have less glucose intolerance, less smoking, similar lipid profiles, and higher blood pressure despite a much larger body compared to the general population, although the presence of subclinical atherosclerosis in these subjects has not been evaluated. This study compared the prevalence of subclinical atherosclerosis in active professional American football players to that in age-, gender-, and race-matched controls derived from the Bogalusa Heart Study. Carotid intimal-medial thickness (CIMT) was used as an indicator of subclinical atherosclerosis in 75 active American football players (23 to 35 years old, 31 white, 44 African-American) as measured by B-mode ultrasonography at Mayo Clinic, Scottsdale, Arizona, on September 13 and 14, 2009. CIMT measurements of 75 athletes were compared to those of 518 matched controls who had CIMT determinations in 1995 and 1996. Two-group t tests determined population similarities between groups. In a generalized linear model, players (overall and by race) had lower CIMT values than controls after age and race adjustment (p <0.001 for all comparisons). Nonlinemen and linemen had lower CIMT values than controls (p < 0.001 and p = 0.004, respectively). In conclusion, active professional American football players, regardless of position, had mean CIMT values similar to or lower than those in a matched general population cohort, suggesting that if the prevalence of subclinical atherosclerosis is increased in retired professional American football players, this occurs after retirement.

Carotid intima-media thickness measurements are not affected by the ultrasound frequency.

OBJECTIVE: Carotid intima-media thickness (IMT) is a B-mode ultrasound measure of subclinical atherosclerosis predictive of future cardiovascular risk. Carotid IMT measurements were historically obtained at an ultrasound frequency of 8 MHz or lower, but it is unknown whether measurements obtained at higher frequencies using newer, more advanced ultrasound technology allow for valid comparison to the older general population databases that are commonly used for the interpretation of carotid IMT results. METHODS: Carotid IMT studies were conducted in 35 consecutive patients at standard (8 MHz) and high (14 MHz) frequencies and measurements were performed by two independent expert readers. Systematic bias was assessed by using the paired t-test and agreement was analyzed with the Bland-Altman method. RESULTS: The sample mean carotid IMT obtained at 14 MHz was 0.006 mm lower than that obtained at 8 MHz. The 95% confidence interval (CI) for the mean difference between frequencies indicated that the population mean for 14 MHz is unlikely to be more than 0.02 mm lower than for 8 MHz (95% CI -0.017 to 0.004). The 95% reference range for the difference between the two transducer frequencies indicated that the thickness obtained at 14 MHz was within 0.05 mm of that obtained at 8 MHz for 95% of subjects. CONCLUSIONS: Carotid IMT measurements obtained at higher transducer frequencies are similar to those obtained at standard frequency. This finding has important clinical implications because it validates comparison of carotid IMT measurements obtained with newer, more advanced ultrasound technology with the landmark reference carotid IMT studies commonly used for interpretation of carotid IMT results.

Usefulness of two-dimensional and speckle tracking echocardiography in "Gray Zone" left ventricular hypertrophy to differentiate professional football player's heart from hypertrophic cardiomyopathy.

Distinguishing the pathologic hypertrophy of hypertrophic cardiomyopathy (HC) from the physiologic hypertrophy of professional football players (PFP) can be challenging when septal wall thickness falls within a "gray zone" between 12 and 16 mm. It was hypothesized that 2-dimensional and speckle-tracking strain (ε) echocardiography could differentiate the hearts of PFPs from those of patients with HC with similar wall thicknesses. Sixty-six subjects, including 28 professional American football players and 21 patients with HC, with septal wall thicknesses of 12 to 16 mm, along with 17 normal controls, were studied using 2-dimensional echocardiography. Echocardiographic parameters, including modified relative wall thickness (RWT; septal wall thickness + posterior wall thickness/left ventricular end-diastolic diameter) and early diastolic annular tissue velocity (e'), were measured. Two-dimensional ε was analyzed by speckle tracking to measure endocardial and epicardial longitudinal ε and circumferential ε and radial cardiac ε. Septal wall thickness was higher in patients with HC than in PFPs (14.7 ± 1.1 vs 12.9 ± 0.9 mm, respectively, p <0.001), while posterior wall thickness showed no difference. RWT was larger in patients with HC than in PFPs (0.68 ± 0.10 vs 0.48 ± 0.06, p <0.001). Longitudinal endocardial ε and radial cardiac ε were significantly higher in PFPs than in patients with HC, while circumferential endocardial ε was no different. RWT was the parameter that most accurately differentiated PFPs from patients with HC. An RWT cut point of 0.6 differentiated PFPs from patients with HC, with an area under the curve of 0.97. In conclusion, a 2-dimensional echocardiographic measure of RWT (septal wall + posterior wall thickness/left ventricular end-diastolic dimension) accurately differentiated PFPs' hearts from those of patients with HC when septal wall thickness was in the gray zone of 12 to 16 mm. Two-dimensional strain analysis identifies variations in myocardial deformation between PFPs and patients with HC with gray-zone hypertrophy.

Coronary artery plaque burden does not affect left ventricular diastolic function in asymptomatic adults with normal ejection fraction.

BACKGROUND: Coronary artery disease (CAD) is commonly cited as a mechanism underlying diastolic dysfunction. However, the association of CAD without ischemia and left ventricular (LV) diastolic dysfunction has not been convincingly demonstrated in asymptomatic patients. The objective of this study was to determine if such a relation exists using coronary artery calcium score (CACS) as a surrogate for coronary atherosclerosis burden. METHODS: Consecutive eligible patients with normal ejection fraction who underwent CACS assessment, echocardiography, and stress testing with negative results for obstructive CAD between August 2006 and September 2007 were included in this retrospective study. Clinical variables were collected from the medical record. Diastolic function classification was based on established echocardiographic guidelines recommended by the American Society of Echocardiography. Statistical analysis was used to identify predictors of CACS. RESULTS: A total of 349 subjects (302 men) aged 58 ± 6 years were studied. Risk factors included hyperlipidemia (n = 202 [58%]), hypertension (n = 127 [36%]), impaired fasting glucose (n = 78 [22%]), and diabetes (n = 21 [6%]). Left atrial volume index was weakly correlated with CACS (r = 0.26, P < .001). There was no significant relationship between CACS and LV diastolic function grade in the entire group (P = .14) or in a subgroup of younger patients (n = 140) who matched the ages qualifying for premature CAD (P = .17). After stepwise elimination multivariate analysis, five variables independently predicted CACS: age (P < .001), hyperlipidemia (P < .001), LA volume index (P < .001), male gender (P = .01), and LV posterior wall thickness (P = .03). CONCLUSIONS: In asymptomatic patients with normal LV ejection fraction and negative cardiac stress test results, CACS does not correlate with LV diastolic function as defined by established Doppler echocardiographic criteria. In the absence of ischemia, postinfarction LV remodeling, or previous coronary artery bypass surgery, CAD does not appear be a cause of LV diastolic dysfunction in asymptomatic patients.

Epicardial fat: an additional measurement for subclinical atherosclerosis and cardiovascular risk stratification?

BACKGROUND: The value of epicardial adipose tissue (EAT) thickness as determined by echocardiography in cardiovascular risk assessment is not well understood. The aim of this study was to determine the associations between EAT thickness and Framingham risk score, carotid intima media thickness, carotid artery plaque, and computed tomographic coronary calcium score in a primary prevention population. METHODS: Patients presenting for cardiovascular preventive care (n = 356) who underwent echocardiography as well as carotid artery ultrasound and/or coronary calcium scoring were included. RESULTS: EAT thickness was weakly correlated with Framingham risk score. The prevalence of carotid plaque was significantly greater in those with EAT thickness ≥ 5.0 mm who either had low Framingham risk scores or had body mass indexes ≥ 25 kg/m(2), compared with those with EAT thickness <5.0 mm. No significant association between EAT thickness and carotid intima-media thickness or coronary calcium score existed. CONCLUSION: EAT thickness ≥ 5.0 mm may identify an individual with a higher likelihood of having detectable carotid atherosclerosis.

Short-term cardiac and noncardiac mortality following liver transplantation.

Objectives. To determine the importance of acute cardiac events as a cause of mortality compared to non-cardiac events in the four month period following liver transplantation (LT) using current preoperative cardiac screening strategies. Patients and Methods. We retrospectively reviewed timing, type, and outcome of adverse cardiac events, and all cause mortality in the 4 month postoperative period in 393 consecutive LT patients from October 1999 to February 2008. Results. Of 30 total deaths (7.6% overall mortality rate), 27 (90%) were due to surgical or medical complications and 3 (10%) were primary cardiac deaths (0.8% cardiac mortality rate). Acute cardiac events occurred in 26 patients (6.6%), including 13 arrhythmias (50%), 7 new onset heart failures (27%), and 6 myocardial infarctions (23%). Twelve of 13 intraoperative events were arrhythmias (92%) including two of three cardiac deaths. Conclusions. Using current preoperative screening recommendations, deaths from primary cardiac events within four months of LT are very uncommon (0.8%), especially compared with deaths related to medical and surgical complications (6.9%).

Carotid ultrasound identifies high risk subclinical atherosclerosis in adults with low framingham risk scores.

BACKGROUND: Worldwide, cardiovascular (CV) disease remains the most common cause of morbidity and mortality. Although effective in predicting CV risk in select populations, the Framingham risk score (FRS) fails to identify many young individuals who experience premature CV events. Accordingly, the aim of this study was to determine the prevalence of high-risk carotid intima-media thickness (CIMT) or plaque, a marker of atherosclerosis and predictor of CV events, in young asymptomatic individuals with low and intermediate FRS (<2% annualized event rate) using the carotid ultrasound protocol recommended by the American Society of Echocardiography and the Society of Vascular Medicine. METHODS: Individuals aged < or = 65 years not taking statins and without diabetes mellitus or histories of coronary artery disease underwent CIMT and plaque examination for primary prevention. Clinical variables including lipid values, family history of premature coronary artery disease, and FRS and subsequent pharmacotherapy recommendations were retrospectively collected for statistical analysis. RESULTS: Of 441 subjects (mean age, 49.7 + or - 7.9 years), 184 (42%; 95% confidence interval, 37.3%-46.5%) had high-risk carotid ultrasound findings (CIMT > or = 75th percentile adjusted for age, gender, and race or presence of plaque). Of those with the lowest FRS of < or =5% (n = 336) (mean age, 48.0 + or - 7.6 years; mean FRS, 2.5 + or - 1.5%), 127 (38%; 95% confidence interval, 32.6%-43.0%) had high-risk carotid ultrasound findings. For individuals with FRS < or = 5% and high-risk carotid ultrasound findings (n = 127; mean age, 47.3 + or - 8.1 years; mean FRS, 2.5 + or - 1.5%), lipid-lowering therapy was recommended by their treating physicians in 77 (61%). CONCLUSIONS: Thirty-eight percent of asymptomatic young to middle-aged individuals with FRS < or = 5% have abnormal carotid ultrasound findings associated with increased risk for CV events. Pharmacologic therapy for CV prevention was recommended in the majority of these individuals. The lack of radiation exposure, relatively low cost, and ability to detect early-stage atherosclerosis suggest that carotid ultrasound for CIMT and plaque detection should continue to be explored as a primary tool for CV risk stratification in young to middle-aged adults with low FRS.

Takotsubo cardiomyopathy: a unique cardiomyopathy with variable ventricular morphology.

Takotsubo cardiomyopathy is an important differential diagnosis of acute coronary syndrome. It is characterized by normal (or near-normal) coronary arteries, regional wall motion abnormalities that extend beyond a single coronary vascular bed, and often, a precipitating stressor. Variants of the classical left ventricular apical ballooning, including mid- or basal left ventricular wall motion abnormalities, are increasingly recognized. Takotsubo cardiomyopathy is not rare, and heightened awareness of this unique cardiomyopathy likely will lead to a higher reported incidence. Diagnosis of takotsubo cardiomyopathy has important implications for clinical management at presentation and afterward. The long-term prognosis is generally favorable; however, a small subset has potentially life-threatening complications during the initial presentation. The pathophysiologic mechanism is unknown, but catecholamine excess likely has a central role.

Noninvasive measurement of central vascular pressures with arterial tonometry: clinical revival of the pulse pressure waveform?

The arterial pulse has historically been an essential source of information in the clinical assessment of health. With current sphygmomanometric and oscillometric devices, only the peak and trough of the peripheral arterial pulse waveform are clinically used. Several limitations exist with peripheral blood pressure. First, central aortic pressure is a better predictor of cardiovascular outcome than peripheral pressure. Second, peripherally obtained blood pressure does not accurately reflect central pressure because of pressure amplification. Lastly, antihypertensive medications have differing effects on central pressures despite similar reductions in brachial blood pressure. Applanation tonometry can overcome the limitations of peripheral pressure by determining the shape of the aortic waveform from the radial artery. Waveform analysis not only indicates central systolic and diastolic pressure but also determines the influence of pulse wave reflection on the central pressure waveform. It can serve as a useful adjunct to brachial blood pressure measurements in initiating and monitoring hypertensive treatment, in observing the hemodynamic effects of atherosclerotic risk factors, and in predicting cardiovascular outcomes and events. Radial artery applanation tonometry is a noninvasive, reproducible, and affordable technology that can be used in conjunction with peripherally obtained blood pressure to guide patient management. Keywords for the PubMed search were applanation tonometry, radial artery, central pressure, cardiovascular risk, blood pressure, and arterial pulse. Articles published from January 1, 1995, to July 1, 2009, were included in the review if they measured central pressure using radial artery applanation tonometry.

Incidence of subclinical atherosclerosis as a marker of cardiovascular risk in retired professional football players.

The purpose of this study was to evaluate subclinical atherosclerosis in retired professional football players. Two hundred one healthy former professional football players (mean age 50.8 years; mean body mass index 31.5 kg/m(2)) were screened for the prevalence of cardiovascular risk factors, metabolic syndrome, and subclinical atherosclerosis by carotid artery ultrasound and compared with a cohort of men of similar body mass index referred for the assessment of subclinical atherosclerosis by carotid ultrasound. The prevalence of carotid artery plaque in the players was not significantly different from that of the body mass index-matched patients (33.3% vs 29.3%, p = 0.45). For the 2 groups, the prevalence of carotid artery plaque was >3 times higher than that reported in general population studies of patients with the same age range, gender, and exclusions. Metabolic syndrome prevalence was higher in linemen than in nonlinemen (45.8% vs 22.5%, p = 0.001), but there was no statistical difference in plaque presence between linemen and nonlinemen (27.1% vs 35.9%, p = 0.23). In conclusion, despite their elite athletic histories, former professional football players have a similar prevalence of advanced subclinical atherosclerosis as a clinically referred population of overweight and obese men.

Assessing individual cardiac risk using extra-cardiac arterial imaging.

Cardiovascular disease is the leading cause of death globally. Cardiovascular risk factors predict the risk of cardiovascular events in populations but have limitations in predicting individual risk. Emerging technologies that non-invasively measure carotid intima media thickness, aortic pressure and brachial artery reactivity may be useful in identifying the vulnerable patient who may benefit from more aggressive preventive therapy. These tests vary between each other in their reproducibility, cost, required operator skill, availability and patient preparation. However, all require further validation for clinical use as screening tests for cardiovascular disease.

Carotid intima-media thickness and coronary artery calcium score as indications of subclinical atherosclerosis.

OBJECTIVE: To determine the ability of carotid intima-media thickness (CIMT) and coronary artery calcium score (CACS) to detect subclinical atherosclerosis in a young to middle-aged, low-risk, primary-prevention population. PATIENTS AND METHODS: Patients aged 36 to 59 years who underwent determination of CIMT and CACS at our institution between May 1, 2004, and April 1, 2008, were included in the study. Those with diabetes mellitus or a history of coronary, peripheral, or cerebral vascular disease were excluded. Other information, such as Framingham risk score (FRS), was obtained by a review of clinical and laboratory data. RESULTS: Of 118 patients, 89 (75%) had a CACS of zero and 94 (80%) were men; mean +/- SD age was 48.9+/-5.7 years. The mean FRS of this group was 4.0; 86 patients (97%) were considered at low risk (<1% annualized rate) of cardiovascular events. Evidence of carotid atherosclerosis was found in 42 (47%; 95% confidence interval, 37%-58%) of these 89 patients; carotid plaque was found in 30 (34%); and CIMT above the 75th percentile was found in 12 (13%) of age-, sex-, and race-matched control patients. Of the 40 patients with low-risk CIMT (below the 50th percentile), 4 (10%) had a CACS at or above the 50th percentile. CONCLUSION: Subclinical vascular disease can be detected by CIMT evaluation in young to middle-aged patients with a low FRS and a CACS of zero. These findings have important implications for vascular disease screening and the implementation of primary-prevention strategies.