Prevalence of subclinical atherosclerosis in asymptomatic diabetic patients by 64-slice computed tomography

Coronary Atherosclerosis Across the Glycemic Spectrum Among Asymptomatic Adults: The Miami Heart Study at Baptist Health South Florida

BACKGROUND

The contemporary burden and characteristics of coronary atherosclerosis, assessed using coronary computed tomography angiography (CCTA), is unknown among asymptomatic adults with diabetes and prediabetes in the United States. The pooled cohort equations and coronary artery calcium (CAC) score stratify atherosclerotic cardiovascular disease risk, but their association with CCTA findings across glycemic categories is not well established.

METHODS

Asymptomatic adults without atherosclerotic cardiovascular disease enrolled in the Miami Heart Study were included. Participants underwent CAC and CCTA testing and were classified into glycemic categories. Prevalence of coronary atherosclerosis (any plaque, noncalcified plaque, plaque with ≥1 high-risk feature, maximal stenosis ≥50%) assessed by CCTA was described across glycemic categories and further stratified by pooled cohort equations-estimated atherosclerotic cardiovascular disease risk and CAC score. Adjusted logistic regression was used to evaluate the associations between glycemic categories and coronary outcomes.

RESULTS

Among 2352 participants (49.5% women), the prevalence of euglycemia, prediabetes, and diabetes was 63%, 30%, and 7%, respectively. Coronary plaque was more commonly present across worsening glycemic categories (euglycemia, 43%; prediabetes, 58%; diabetes, 69%), and similar pattern was observed for other coronary outcomes. In adjusted analyses, compared with euglycemia, prediabetes and diabetes were each associated with higher odds of any coronary plaque (OR, 1.30 [95% CI, 1.05-1.60] and 1.75 [1.17-2.61], respectively), noncalcified plaque (OR, 1.47 [1.19-1.81] and 1.99 [1.38-2.87], respectively), and plaque with ≥1 high-risk feature (OR, 1.65 [1.14-2.39] and 2.53 [1.48-4.33], respectively). Diabetes was associated with stenosis ≥50% (OR, 3.01 [1.79-5.08]; reference=euglycemia). Among participants with diabetes and estimated atherosclerotic cardiovascular disease risk <5%, 46% had coronary plaque and 10% had stenosis ≥50%. Among participants with diabetes and CAC=0, 30% had coronary plaque and 3% had stenosis ≥50%.

CONCLUSIONS

Among asymptomatic adults, worse glycemic status is associated with higher prevalence and extent of coronary atherosclerosis, high-risk plaque, and stenosis. In diabetes, CAC was more closely associated with CCTA findings and informative in a larger population than the pooled cohort equations.

Coronary computed tomography angiography as a screening tool for moderate-high risk asymptomatic type 2 diabetes mellitus patients

Background

There are few data on the clinical significance of coronary computed tomography angiography (CCTA) in asymptomatic type 2 diabetes mellitus (T2DM) patients. We performed a retrospective study to evaluate coronary heart disease (CHD) screening in asymptomatic patients with T2DM using CCTA and CHD risk stratification prediction.

Materials and methods

Data from 141 T2DM patients (58 ± 8 years, 57% males) without known symptoms suggestive of CHD who underwent CCTA were retrospectively analyzed. The patients were classified into three subgroups based on United Kingdom prospective diabetes study (UKPDS) CHD risk stratification prediction. Seventy-four patients without diabetes mellitus and CHD who underwent CCTA successively were chosen as the control group. The segment involvement score (SIS), segment stenosis score (SSS), stenosis coefficient (SC), severe proximal plaque (SPP) positive ratio and CCTA-adapted Leaman score (CT-LeSc) based on CCTA data were evaluated and compared among the groups.

Results

Compared with the patients in the control group, patients in the moderate-high risk DM groups had higher scores on the SIS, SSS, SC, CT-LeSc, and a higher SPP positive ratio (all p-values < 0.001), and no difference was observed between the low-risk group and the control group (p = 0.136, p = 0.088, p = 0.0.067, p = 0.225, p = 1.000, respectively). Compared with patients in the control group, the patients in the moderate-high risk DM groups had increased odds of SIS > 3 [odds ratio (OR) = 6.557, p < 0.001; OR = 4.455, p < 0.001, respectively], SSS > 5 (OR = 5.727, p < 0.001; OR = 5.144, p < 0.001, respectively), CT-LeSc > 8.7 (OR = 3.780, p = 0.001; OR = 2.804, p = 0.007, respectively), and obstructive stenosis (OR = 7.233, p < 0.001; OR = 5.787, p < 0.001, respectively).

Conclusion

The moderate-high CHD risk patients had increased odds of obstructive coronary artery stenosis, and the distribution of coronary artery stenosis was more extensive and more severe in that group compared to the patients without diabetes mellitus and CHD. CHD can be effectively screened in moderate-high risk asymptomatic T2DM patients using CCTA.

Increased high-risk coronary plaque burden is associated with arterial stiffness in patients with type 2 diabetes without clinical signs of coronary artery disease: a computed tomography angiography study

OBJECTIVES

Arterial stiffness and subclinical coronary atherosclerosis may yield valuable information on cardiovascular risk. We aimed to characterize coronary atherosclerosis in asymptomatic patients with type 2 diabetes and healthy controls and to investigate the association between baseline arterial stiffness and coronary plaque volumes after 5-year follow-up.

METHODS

Data from 45 patients and 61 matched controls were available for coronary plaque assessment. For analysis including carotid-femoral pulse wave velocity (PWV), 43 patients and 55 controls were available. At follow-up, mean (SD) age of participants was 63 ± 10 years, and mean diabetes duration (SD) in the patient group was 7.8 ± 1.4 years. Arterial stiffness (PWV) was assessed by tonometry at both visits. Total, calcified, noncalcified, low-density noncalcified coronary plaques volumes and other plaque characteristics were assessed by coronary computed tomography angiography at follow-up.

RESULTS

Despite of similar or better blood pressure and plasma lipid control, patients had, compared with controls, a higher number of plaques with spotty calcifications (P < 0.01) and remodeling index more than 1.1 (P < 0.05), larger calcified plaque volumes [patients vs.

CONTROLS

11 (0-65) vs. 3 (0-30) μl (P = 0.03)] and higher PWV [patients vs. controls at baseline: 9.1 ± 2.2 vs. 7.9 ± 1.4 m/s (P < 0.01), at follow-up: 9.3 ± 2.3 vs. 8.4 ± 1.8 m/s (P = 0.02)]. Baseline PWV was associated with volumes of all plaque types in crude analysis (P < 0.01) and with low-density noncalcified plaque volume in analysis adjusted for age, sex, diabetes and blood pressure (P = 0.01).

CONCLUSION

Coronary plaques with unfavorable characteristics are more prevalent in well controlled asymptomatic patients with type 2 diabetes compared with healthy controls and independently associated with arterial stiffness.Clinical trials registration number: NCT02001532.

The Cardiovascular Trial of the Testosterone Trials: rationale, design, and baseline data of a clinical trial using computed tomographic imaging to assess the progression of coronary atherosclerosis

BACKGROUND

Data from prior studies have yielded inconsistent results on the association of serum testosterone levels with the risk for cardiovascular disease. There are no clinical trial data on the effects of testosterone replacement therapy on plaque progression.

OBJECTIVE

We designed a study to investigate the effect of testosterone therapy on coronary artery plaque progression using serial coronary computed tomographic angiography (CCTA). In this paper, we describe the study design, methods, and characteristics of the study population.

METHODS

The Cardiovascular Trial of the Testosterone Trials (TTrials; NCT00799617) is a double-blind, placebo-controlled trial of 1 year of testosterone therapy in men 65 years or older with clinical manifestations of androgen deficiency and unequivocally low serum testosterone concentrations (<275 ng/dl). CCTA performed at baseline and after 12 months of therapy will determine the effects of testosterone on the progression of the total volume of noncalcified plaques. All scans are evaluated at a central reading center by an investigator blinded to treatment assignment.

RESULTS

A total of 165 men were enrolled. The average age is 71.1 years, and the average BMI is 30.7. About 9% of men had a history of myocardial infarction, 6% angina, and 10% coronary artery revascularization. A majority reported hypertension and/or high cholesterol; 31.8% reported diabetes. Total noncalcified plaque at baseline showed a slight but nonsignificant trend toward lower plaque volume with higher serum testosterone concentrations (P=0.12).

CONCLUSION

The Cardiovascular Trial will test the hypothesis that testosterone therapy inhibits coronary plaque progression, as assessed by serial CCTA.

Comparison of Coronary Computed Tomographic Angiographic Findings in Asymptomatic Subjects With Versus Without Diabetes Mellitus

There are limited data on the impact of diabetes mellitus (DM) on the risk of subclinical atherosclerosis. Therefore, we sought to investigate the impact of DM on the risk of subclinical atherosclerosis in asymptomatic subjects. We analyzed 2,034 propensity score-matched asymptomatic subjects who underwent coronary computed tomographic angiography (mean age 55.9 ± 8.2 years; men 1,725 [84.8%]). Coronary artery calcium score, degree and extent of coronary artery disease (CAD), and clinical outcomes were assessed. High-risk CAD was defined as at least 2-vessel coronary disease with proximal left anterior descending artery involvement, 3-vessel disease, or left main disease. Compared with subjects without DM, those matched with DM had higher coronary artery calcium score (89.9 ± 240.4 vs 62.8 ± 179.5, p = 0.004) and more significant CAD (≥50% diameter stenosis, 15.2% vs 10.2%, p = 0.001), largely in the form of 1-vessel disease (10.8% vs 7.3%, p = 0.007). However, there were no significant differences between matched pairs in significant CAD in the left main or proximal left anterior descending artery (5.3% vs 3.8%, p = 0.138), multivessel disease (4.4% vs 2.9%, p = 0.101), and high-risk CAD (4.3% vs 2.7%, p = 0.058). During the follow-up period (median 21.8, interquartile range 15.2 to 33.4 months), there was no significant difference in the composite of all-cause death, myocardial infarction, acute coronary syndrome, and coronary revascularization between 2 groups (hazard ratio 1.438, 95% confidence interval 0.844 to 2.449, p = 0.181). In asymptomatic subjects, those matched with DM have more subclinical atherosclerosis, mainly confined to non-high-risk CAD, than those matched without DM, and there are no differences in high-risk CAD and clinical outcomes.

Risk score model for the assessment of coronary artery disease in asymptomatic patients with type 2 diabetes

No model has been developed to predict significant coronary artery disease (CAD) on coronary computed tomographic angiography (CCTA) in asymptomatic type 2 diabetes. Therefore, we sought to develop a model for the prediction of significant CAD on CCTA in these patients. We analyzed 607 asymptomatic patients with type 2 diabetes who underwent CCTA. The cardiac event was defined as a composite of cardiac death, nonfatal myocardial infarction, acute coronary syndrome, and coronary revascularization. Significant CAD (diameter stenosis ≥50%) in at least one coronary artery on CCTA was observed in 188 (31.0%). During the follow-up period (median 4.3 [interquartile range, 3.7-4.8] years), 71 patients had 83 cardiac events. Clinical risk factors for significant CAD were age, male gender, duration of diabetes, hypertension, current smoking, family history of premature CAD, previous history of stroke, ratio of total cholesterol to high-density lipoprotein cholesterol, and neuropathy. Using these variables, we formulated a risk score model, and the scores ranged from 0 to 17 (area under the curve = 0.727, 95% confidence interval = 0.714-0.739, P < 0.001). Patients were categorized into low (≤3), intermediate (4-6), or high (≥7) risk group. There were significant differences between the risk groups in the probability of significant CAD (12.6% vs 29.4% vs 57.7%, P for all < 0.001) and 5-year cardiac event-free survival rate (96.6% ± 1.5% vs 88.9% ± 1.8% vs 73.8% ± 4.1%, log-rank P for trend < 0.001). This model predicts significant CAD on CCTA and has the potential to identify asymptomatic type 2 diabetes with high risk.

Coronary computed tomographic angiographic findings in asymptomatic patients with type 2 diabetes mellitus

There are limited data regarding the role of coronary computed tomographic angiography (CCTA) in asymptomatic patients with type 2 diabetes mellitus. We analyzed 557 asymptomatic type 2 diabetic patients who underwent CCTA. Cardiac event was defined as a composite of cardiac death, nonfatal myocardial infarction, acute coronary syndrome requiring hospitalization, or late revascularization. Atherosclerotic plaques were observed in 395 patients (70.9%), and 170 patients (30.5%) showed significant coronary artery disease (CAD) on CCTA. Ninety-two patients (16.5%) were associated with a significant stenosis in the left main or proximal left anterior descending artery. During the follow-up period (33.7 ± 7.8 months), although an excellent prognosis was observed in patients without significant CAD on CCTA, those with significant CAD showed more cardiac events (7.1% vs 0.5%) and lower 3-year event-free survival rates (99.2 ± 0.6% vs 90.9 ± 2.6%, p <0.001). Furthermore, in group with significant CAD, patients with significant CAD in the left main or proximal left anterior descending artery had more cardiac events (10.9% vs 2.6%) and lower 3-year event-free survival rates (97.4 ± 1.8% vs 86.1 ± 4.2%, p = 0.049). On multivariate analysis, family history of premature CAD, previous history of stroke, higher UK Prospective Diabetes Study 10-year risk scores, neuropathy, and retinopathy were independent clinical predictors of having significant CAD and left main or proximal left anterior descending artery significant CAD on CCTA. In conclusion, about 1/3 of asymptomatic type 2 diabetic patients had significant CAD on CCTA with a subsequent high risk for cardiac events. These findings suggest that CCTA may have a potential role in identifying patients with high cardiovascular risks in asymptomatic type 2 diabetes.

New strategy for detection of subclinical coronary atherosclerosis in asymptomatic patients with type 2 diabetes based on cardiac multi-detector computed tomography and treadmill test

BACKGROUND

The current screening strategy for subclinical coronary atherosclerosis in asymptomatic diabetic patients is not sufficient in real clinical practice. A new strategy was investigated that uses cardiac multi-detector computed tomography (MDCT) and a treadmill test (TMT).

METHODS AND RESULTS

A total of 445 self-referred asymptomatic diabetic patients underwent cardiac MDCT. The treatment plan was determined according to the new strategy that uses MDCT and TMT. All patients underwent clinical follow-up and cardiac events were investigated. The incidence of subclinical atherosclerosis was 49.4%. The group without plaque underwent clinical follow-up without treatment and did not experience any cardiac events in 675.1 person-years of follow-up. Among patients with subclinical atherosclerosis without significant stenosis (n=136) who received medical treatment only, 11 patients experienced cardiac events over 326.4 person-years. The patients with significant stenosis (n=84) underwent TMT. Patients with positive TMT (n=14) underwent coronary angiograms and revascularization therapy was performed in all of them over 39.2 person-years. Patients with negative TMT (n=70) underwent medical treatment, and 27 of them experienced cardiac events. The incidence of cardiac death was 0% during 3 years of follow-up.

CONCLUSIONS

 The new strategy for detecting subclinical atherosclerosis on MDCT combined with TMT may be a useful method for minimizing the mortality rate from cardiovascular disease in asymptomatic diabetic patients. 

Significant coronary stenosis in asymptomatic Chinese with different glycemic status

OBJECTIVE

To evaluate coronary artery stenosis in early diabetes or prediabetes asymptomatic of myocardial ischemia in community-dwelling Chinese adults.

RESEARCH DESIGN AND METHODS

Age- and sex-matched participants with normal glucose regulation (NGR), prediabetes, or diabetes diagnosed within 5 years, asymptomatic of coronary artery disease (CAD), were randomly selected from a community-dwelling Chinese population aged 40-60 years. Dual-source computed tomography coronary angiography was used to evaluate the existence and extent of coronary stenosis, which was considered significant if >50% narrowing of vessel lumen was detected.

RESULTS

After excluding uninterpretable segments attributable to motion artifacts, a total of 135 participants with NGR, 132 with prediabetes, and 134 with diabetes participated in data analysis. Significant coronary stenosis was detected in 10 (7.4%), 10 (7.6%), and 22 (16.4%) individuals with NGR, prediabetes, and diabetes, respectively (P for trend = 0.029). Diabetes, rather than prediabetes, was associated with a significant 2.34-fold elevated risk [odds ratio (OR) 2.34 (95% CI 1.01-5.43); P = 0.047] of significant coronary stenosis as compared with that associated with NGR. Levels of glucose evaluation were independently and significantly associated with risks of significant coronary stenosis in diabetes. Each 1-SD increase in fasting plasma glucose, 2-h postload plasma glucose, and HbA1c conveyed 2.11-fold, 1.73-fold, and 1.81-fold higher risks of significant coronary stenosis, respectively, after adjustment for other conventional cardiovascular risk factors.

CONCLUSIONS

Using a noninvasive CAD diagnostic modality such as dual-source computed tomography coronary angiography, we detected a markedly elevated risk of significant coronary stenosis with early diabetes in asymptomatic Chinese adults.

Use of cardiac CT angiography imaging in an epidemiology study - the Methodology of the Multicenter AIDS Cohort Study cardiovascular disease substudy

OBJECTIVE

The methodology for use of cardiac CT angiography (CTA) in low risk populations is not well defined. In order to present a reference for future studies, we present CTA methodology that is being used in an epidemiology study- the Multicenter AIDS Cohort Study (MACS).

METHODS

The Multicenter AIDS Cohort Study (MACS) is an on-going multicenter prospective, observational cohort study. The MACS Cardiovascular Disease substudy plans to enroll 800 men (n= 575 HIV seropositive and n=225 HIV seronegative) age 40-70 years for coronary atherosclerosis imaging using cardiac CTA. The protocol includes heart rate (HR) optimization with beta- blockers; use of proper field of view; scan length limitation; prospective ECG-gating using the lowest beam voltage possible. All scans are evaluated for presence, extent, and composition of coronary atherosclerosis, left atrial volumes, left ventricular volume and mass and non-coronary cardiac pathology.

RESULTS

The first 498 participants had an average radiation dose of 2.5±1.6 milliSieverts (mSv) for the cardiac CTA study. Overall quality of scans was fair to excellent in 98.6% of studies. There were three significant adverse events-two allergic reactions to contrast and one subcutaneous contrast extravasation.

CONCLUSION

Cardiac CTA was safe and afforded a low effective radiation exposure to these asymptomatic research participants and provides valuable cardiovascular endpoints for scientific analysis. The cardiac CTA methodology described here may serve as a reference for use in future epidemiology studies aiming to assess coronary atherosclerosis and cardiac anatomy in low risk populations while minimizing radiation exposure.

Subclinical coronary atherosclerosis identified by coronary computed tomographic angiography in asymptomatic morbidly obese patients

Obesity is a common public health problem and obese individuals in particular have a disproportionate incidence of acute coronary events. This study was undertaken to identify coronary artery lesions as well as associated clinical features, risk factors and demographics in patients with a body mass index (BMI) >40 kg/m² without known coronary artery disease (CAD). Morbidly obese subjects were prospectively recruited to undergo coronary computed tomographic angiography (CCTA) using a dual-source computed tomography (CT) system. CAD was defined as the presence of any atherosclerotic lesion in any one coronary artery segment. The presence, location, and severity of atherosclerosis were related to patient characteristics. Forty-one patients (28 women, mean age, 50.4±10.0 years, mean BMI, 43.8±4.8 kg/m²) served as the study population. Of these, 25 patients (61%) had at least one coronary stenosis. All but 2 patients within the CAD cohort had coronary artery calcium (CAC) scores >0, and most plaques identified (75.4%) were non-calcified. There was a predilection of calcified and non-calcified atherosclerosis involving the left anterior descending (LAD) coronary artery compared with other coronary segments. Univariate predictors of CAD included older age, dyslipidemia, and diabetes. In this preliminary study of young morbidly obese patients, CCTA detected a high prevalence of calcified and non-calcified CAD, although the later predominated.

Accelerated subclinical coronary atherosclerosis in patients with familial hypercholesterolemia

OBJECTIVES

We determined the extent, severity, distribution and type of coronary plaques in cardiac asymptomatic patients with familial hypercholesterolemia (FH) using computed tomography (CT).

BACKGROUND

FH patients have accelerated progression of coronary artery disease (CAD) with earlier major adverse cardiac events. Non-invasive CT coronary angiography (CTCA) allows assessing the coronary plaque burden in asymptomatic patients with FH.

MATERIALS AND METHODS

A total of 140 asymptomatic statin treated FH patients (90 men; mean age 52 ± 8 years) underwent CT calcium scoring (Agatston) and CTCA using a Dual Source CT scanner with a clinical follow-up of 29 ± 8 months. The extent, severity (obstructive or non-obstructive plaque based on >50% or <50% lumen diameter reduction), distribution and type (calcified, non-calcified, or mixed) of coronary plaque were evaluated.

RESULTS

The calcium score was 0 in 28 (21%) of the patients. In 16% of the patients there was no CT-evidence of any CAD while 24% had obstructive disease. In total 775 plaques were detected with CT coronary angiography, of which 11% were obstructive. Fifty four percent of all plaques were calcified, 25% non-calcified and 21% mixed. The CAD extent was related to gender, treated HDL-cholesterol and treated LDL-cholesterol levels. There was a low incidence of cardiac events and no cardiac death occurred during follow-up.

CONCLUSION

Development of CAD is accelerated in intensively treated male and female FH patients. The extent of CAD is related to gender and cholesterol levels and ranges from absence of plaque in one out of 6 patients to extensive CAD with plaque causing >50% lumen obstruction in almost a quarter of patients with FH.

Interrelationship between myocardial perfusion imaging, coronary calcium score, and endothelial function in asymptomatic diabetics and controls

BACKGROUND

Coronary artery disease is a leading cause of death among diabetics, and silent ischemia is a major concern in patients with diabetes mellitus (DM).

METHODS

To detect the prevalence of ischemia in diabetics by myocardial perfusion imaging (MPI), and compare it to a control group without DM but with coronary risk factors, as well as to explore the relationship between silent ischemia, endothelial dysfunction, and coronary calcium, 59 patients (Group I) and 42 controls (Group II) were included. All underwent clinical and laboratory evaluations, gated MPI, brachial artery vasodilation measured by ultrasonography, and coronary calcium score (CCS).

RESULTS

Twenty diabetics showed perfusion defects, vs seven controls (P = .04). There was no significant difference between both groups regarding the brachial artery vasodilator responsiveness: 4.49% ± 4.26% (diabetics) vs 4.70% ± 4.98% (controls). Mean CCS was 74 in diabetics vs five in controls (P = .01). The only risk factor significantly associated with an abnormal MPI was the presence of diabetes (P = .03). In the whole population of patients and in diabetics, the abnormal endothelium-dependent vasodilation, the CCS >100, and the cholesterol/HDL ratio >4, showed an OR >1. CCS exhibited the higher OR among the whole population: OR 2.15 [95% CI 0.42-10.99]; while for diabetics it was the cholesterol/HDL ratio: OR 3.95 [95% CI 0.71-21.84].

CONCLUSIONS

Reversible perfusion defects and coronary calcium are more frequent in diabetics. CCS, abnormal endothelium-dependent vasodilation, and cholesterol/HDL ratio higher than 4, showed an association with perfusion abnormalities in asymptomatic diabetics.

Incidence of subclinical atherosclerosis in asymptomatic type-2 diabetic patients: the potential of multi-slice computed tomography coronary angiography

BACKGROUND AND OBJECTIVES

Type-2 diabetic patients constitute a high-risk population for atherosclerosis. Primary prevention, although recommended, is not well funded. Our aim was to evaluate the degree of subclinical atherosclerosis, in asymptomatic diabetic patients, using coronary multi-slice computed tomography (MSCT) angiography.

METHODS

We prospectively studied 71 diabetic patients without any symptoms or documentation of atherosclerotic disease. Coronary MSCT angiography was performed in all patients and coronary artery calcium score (CACS) was evaluated. The number of diseased coronary segments was determined and classified as obstructive or nonobstructive and fibrolipid or calcified lesions. The mean follow-up was 29.5±6.6 months. Major adverse cardiovascular events were registered.

RESULTS

The mean age was 59±10 years, 48% were female patients. The duration of diabetes was 12.5±8.7 years. CACS ranged from 0 to 1293 Agatston units (153±269.1). Image quality was generally good, allowing satisfactory evaluation of most of the coronary artery segments. CACS was 0 in 28 patients, but in nine patients MSCT angiography showed fibrolipid plaques. Obstructive coronary artery disease was present in 26.7% of the patients (5.6% with multivessel disease). During the follow-up period, six major adverse cardiovascular events were detected in patients, five of whom had a CACS more than 100 Agatston units.

CONCLUSION

This study shows a high prevalence of silent atherosclerotic lesions in type-2 diabetic patients, reinforcing the importance of risk factor modification even when calcified disease is absent. Coronary MSCT angiography can be performed to identify the atherosclerotic burden and may be an important test in selecting the patients who are benefiting the most from primary prevention.

Comparison of the diagnostic performance of 64-slice computed tomography coronary angiography in diabetic and non-diabetic patients with suspected coronary artery disease

BACKGROUND

Diabetics have high prevalence of subclinical coronary artery disease (CAD) with typical characteristics (diffuse disease, large calcifications). Although 64-slice multidetector computed tomography (MDCT) coronary angiography has high diagnostic accuracy to detect CAD, its diagnostic performance in diabetics with suspected CAD is unknown. To compare the diagnostic performance of 64-slice MDCT between diabetics and non-diabetics with suspected CAD scheduled for invasive coronary angiography (ICA).

METHODS

We enrolled one hundred and five diabetic patients (92 men, age 65 +/- 9 years, Group 1) and 105 non-diabetic patients (63 men, age 63+/-5 years, Group 2) with indication to ICA for suspected CAD undergoing coronary 64-slice MDCT before ICA.

RESULTS

In Group 1, the overall feasibility of coronary artery visualization was 93.8%. The most frequent artifact was blooming due to large coronary calcifications (54 artifacts, 67%). In Group 2, the overall feasibility was significantly higher vs. Group 1 (97%, p < 0.0001). In Group 1, the segment-based analysis showed a MDCT sensibility, specificity, positive predictive value, negative predictive value and accuracy for the detection of ≥50% luminal narrowing of 77%, 90%, 70%, 93% and 87%, respectively. In Group 2, all these parameters were significantly higher vs. Group 1. In the patient-based analysis, specificity, negative predictive value and accuracy were significantly lower in Group 1 vs. Group 2.

CONCLUSIONS

Although MDCT has high sensitivity for early identification of significant CAD in diabetics, its diagnostic performance is significantly reduced in these patients as compared to non-diabetics with similar clinical characteristics.

Interobserver variations of plaque severity score and segment stenosis score in coronary arteries using 64 slice multidetector computed tomography: a substudy of the ACCURACY trial

BACKGROUND

Assessing the severity of coronary plaque for the risk stratification and management of coronary artery disease is important. Multidetector computed tomography has been shown to be a useful tool to measure coronary plaque; however, interreader variability is a concern.

OBJECTIVE

We measured interobserver variations of plaque severity score (PSS) and segment stenosis score (SSS) as measured by the total plaque severity score (TPS) and total segment stenosis score (TSS).

METHODS

Cardiac CT scans (n = 221) of the ACCURACY trial were interpreted by 3 different readers blinded to patient characteristics. PSS (mild, 1; moderate, 2; and severe, 3) and SSS (stenosis 1%-29%, 1; 30%-49%, 2; 50%-69%, 3; and ≥70%, 4) were calculated with the 15-segment American Heart Association model. TPS and TSS were determined by summing the segments for each interpreter. TPS and TSS were compared for correlation and variation among any 2 of the 3 readers.

RESULTS

A highly significant correlation was observed among any 2 of the 3 readers for both TPS and TSS. For TPS, the r = 0.91, 0.93, 0.94 (P < 0.001) for A vs B, B vs C, A vs C, respectively, and for TSS, r = 0.91, 0.92, 0.93 (P < 0.001) for A vs B, B vs C, A vs C, respectively. On Bland Altman plot, the mean difference between the scores of any 2 readers was 3.33 ± 3.93, 1.65 ± 2.88, and 1.68 ± 2.92 for TPS and 4.19 ± 4.73, 2.54 ± 4.02, and 1.65 ± 3.18 for TSS.

CONCLUSION

Semiquantitative measures of coronary plaque burden, including the TPS and TSS, can be determined with a high degree of interobserver agreement, suggesting their potential role as tools to aid in the assessment of coronary heart disease.

Prognostic value of coronary computed tomographic angiography in diabetic patients without known coronary artery disease

OBJECTIVE

Diabetic patients have a high prevalence of coronary artery disease (CAD), but timely diagnosis of CAD remains challenging. We assessed the ability of coronary computed tomography angiography (CCTA) to detect CAD in diabetic patients and to predict subsequent cardiac events.

RESEARCH DESIGN AND METHODS

We analyzed 140 diabetic patients without known CAD undergoing CCTA; 1,782 patients without diabetes were used as a control group. Besides calcium scoring and the degree of the most severe stenosis, the atherosclerotic burden score counting the number of segments having either a nonstenotic plaque or a stenosis was recorded. The primary end point was a composite of hard cardiac events defined as all-cause death, nonfatal myocardial infarction, or unstable angina requiring hospitalization.

RESULTS

During a mean follow-up of 33 months, there were seven events in the diabetic group and 24 events in the control group. The best predictor in diabetic patients was the atherosclerotic burden score: the annual event rate ranged from 0.5% for patients with <5 lesions to 9.6% for patients with >9 lesions, resulting in a hazard ratio (HR) of 1.3 (95% CI 1.1-1.7) for each additional lesion (P = 0.005). For comparison, in nondiabetic patients the annual event rate ranged from 0.3 to 2.2%, respectively, resulting in an HR of 1.2 (95% CI 1.1-1.3, P < 0.001). The atherosclerotic burden score improved the prognostic value of conventional risk factors significantly (P < 0.001).

CONCLUSIONS

In diabetic patients without known CAD, CCTA can identify a patient group at particularly high risk for subsequent hard cardiac events.

Calcification in atherosclerosis

Coronary calcification has long been known to occur as a part of the atherosclerotic process, although whether it is a marker of plaque stability or instability is still a topic of considerable debate. Coronary calcification is an active process resembling bone formation within the vessel wall and, with the advances in CT technology of the past decade, can be easily quantified and expressed as a coronary artery calcium (CAC) score. The extent of calcium is thought to reflect the total coronary atherosclerotic burden, which has generated interest in using CAC as a marker of risk of cardiovascular events. The current consensus is that large amounts of CAC identify a highly vulnerable patient rather than a vulnerable plaque or vulnerable vessel. Indeed, CAC has incremental prognostic value beyond traditional risk factors in various subsets of the population. Furthermore, whereas the presence of CAC is associated with increased risk, a zero CAC score predicts excellent short-term to mid-term prognosis, even in high-risk patients. The advent of CT angiography has perhaps clouded the importance of CAC as a long-term marker of risk, as opposed to the presence of luminal stenoses that are associated with a more immediate risk of events.

Imaging diabetes mellitus with coronary computed tomography angiography, cardiovascular magnetic resonance, and positron emission tomography

The prevalence and medical expense associated with diabetes mellitus continue to increase. Using the diagnostic imaging techniques of coronary computed tomography angiography, cardiovascular magnetic resonance, and positron emission tomography, it may be possible to make earlier, non-invasive diagnoses of the type and extent of disease, thereby preventing or delaying some morbidity and mortality.