Diagnostic accuracy of 64 multidetector computed tomographic angiography in peripheral vascular disease.

BACKGROUND: Previous studies of multidetector CT (MDCT) of the lower extremities for the detection of peripheral vascular disease showed high diagnostic accuracy but were performed with older generation systems. OBJECTIVE: The purpose of this study was to evaluate the diagnostic accuracy of 64 MDCT for the detection of hemodynamically significant disease within the lower extremity peripheral vasculature as compared to digital subtraction angiography (DSA). METHODS: Twenty-eight consecutive patients with symptomatic lower extremity intermittent claudication and an abnormal ankle-brachial index (ABI; less than 0.9) were evaluated by both 64 MDCT and DSA. Axial images were acquired with a 64 multidetector general electric light speed VCT scanner. Images were analyzed using a GE Advantage workstation (AW 4.3) capable of advanced image processing and manipulation. The aorto-iliac and lower extremity arteries were divided into 15 segments per limb (30 segments per patient). Eight hundred forty segments were analyzed in a blinded fashion by physicians with level III CT certification. Segments were classified as grade I (<10% stenosis), grade II (10-49%), grade III (50-99%), and grade IV (occlusion). RESULTS: For all segments evaluated, the overall diagnostic accuracy for detecting grade III and IV lesions was 98% with a sensitivity of 99% and a specificity of 98%. For the aorto-iliac segments, the diagnostic accuracy was 98% with a sensitivity of 100% and a specificity of 99%. For the femoro-popliteal segments, the overall accuracy was 98% with a sensitivity of 100% and a specificity of 99%. For the infra-popliteal segments, the overall accuracy was 98% with a sensitivity of 97% and a specificity of 99%. One segment could not be visualized by MDCT compared to 49 segments that could not be visualized by DSA. CONCLUSIONS: This study demonstrates excellent diagnostic accuracy of 64 MDCT in the detection of hemodynamically significant disease of the lower extremities. More segments are visualized using 64 MDCT than DSA, allowing more complete visualization of the vascular tree. CT angiography should be considered in the diagnostic evaluation of symptomatic patients with peripheral vascular disease.

Vascular function measured by fingertip thermal reactivity is impaired in patients with metabolic syndrome and diabetes mellitus.

Digital thermal monitoring (DTM) of vascular function has already been shown to correlate well with coronary artery calcium (CAC) score and coronary artery disease. To determine its utility in the metabolic syndrome (MS) and diabetes mellitus (DM), 233 asymptomatic patients with DM/MS but without coronary artery disease underwent DTM during and after 5 minutes of supra-systolic arm cuff inflation, as well as CAC. Post-cuff deflation adjusted temperature rebound (aTR) was lower in MS and DM compared with the normal group. The odds ratio of lowest vs upper 2 tertiles of aTR was 2.3 for MS and 3.5 for DM compared with the normal group, independent of age, sex, and risk factors. The area under the receiver operating characteristic curve to predict CAC > or =100 was 0.69 for metabolic status (DM/MS), 0.79 for aTR, and 0.87 for both. This study demonstrates that vascular dysfunction measured by DTM is associated with DM/MS and could potentially be used to detect asymptomatic individuals with increased subclinical atherosclerosis.

Aged garlic extract supplemented with B vitamins, folic acid and L-arginine retards the progression of subclinical atherosclerosis: a randomized clinical trial.

OBJECTIVES: Previous studies demonstrated that aged garlic extract reduces multiple cardiovascular risk factors. This study was designed to assess whether aged garlic extract therapy with supplements (AGE+S) favorably affects inflammatory and oxidation biomarkers, vascular function and progression of atherosclerosis as compared to placebo. METHODS: In this placebo-controlled, double-blind, randomized trial (conducted 2005-2007), 65 intermediate risk patients (age 60+/-9 years, 79% male) were treated with a placebo capsule or a capsule containing aged garlic extract (250 mg) plus Vitamin B12 (100 microg), folic acid (300 microg), Vitamin B6 (12.5 mg) and l-arginine (100 mg) given daily for a 1 year. All patients underwent coronary artery calcium scanning (CAC), temperature rebound (TR) as an index of vascular reactivity using Digital Thermal Monitoring (DTM), and measurement of lipid profile, autoantibodies to malondialdehyde (MDA)-LDL, apoB-immune complexes, oxidized phospholipids (OxPL) on apolipoprotein B-100 (OxPL/apoB), lipoprotein (a) [Lp (a)], C-reactive protein (CRP), homocysteine were measured at baseline and 12 months. CAC progression was defined as an increase in CAC>15% per year and an increase in TR above baseline was considered a favorable response. RESULTS: At 1 year, CAC progression was significantly lower and TR significantly higher in the AGE+S compared to the placebo group after adjustment of cardiovascular risk factors (p<0.05). Total cholesterol, LDL-C, homocysteine, IgG and IgM autoantibodies to MDA-LDL and apoB-immune complexes were decreased, whereas HDL, OxPL/apoB, and Lp (a) were significantly increased in AGE+S to placebo. CONCLUSION: AGE+S is associated with a favorable improvement in oxidative biomarkers, vascular function, and reduced progression of atherosclerosis.

Digital thermal monitoring of vascular function: a novel tool to improve cardiovascular risk assessment.

Digital thermal monitoring (DTM) of vascular function during cuff-occlusive reactive hyperemia relies on the premise that changes in fingertip temperature during and after an ischemic stimulus reflect changes in blood flow. To determine its utility in individuals with and without known coronary heart disease (CHD), 133 consecutive individuals (age 54 +/- 10 years, 50% male, 19 with known CHD) underwent DTM during and after 2 minutes of supra-systolic arm cuff inflation. Fingertip temperatures of the occluded and non-occluded fingertips were measured simultaneously. Post-cuff deflation temperature rebound (TR) was lower in the CHD patients and in those with an increased Framingham risk score (FRS) compared to the normal group. After adjustment for age, sex, and cardiac risk factors, TR was significantly lower in those with CHD compared to those without CHD (p < 0.05). This study demonstrates that vascular dysfunction measured by DTM is associated with CHD and an increased FRS, and could potentially be used to identify high-risk patients.

Cardiac computed tomographic angiography in an outpatient setting: an analysis of clinical outcomes over a 40-month period.

BACKGROUND: Cardiac computed tomographic angiography (CTA) provides for accurate noninvasive diagnosis of coronary artery disease (CAD). OBJECTIVES: We analyzed the clinical outcomes over 40 months in patients with and without CAD as determined by CTA in an outpatient setting. METHODS: Consecutive symptomatic patients (n = 493; mean age, 58 +/- 15 years; 70% men) with an intermediate likelihood of CAD referred for outpatient CTA evaluation were prospectively followed for a mean of 40 +/- 9 months. RESULTS: Results of CTA included as normal (defined as normal coronary lumen), found in 32% (157), nonobstructive disease (<50% luminal stenosis) in 41% (204), obstructive disease (>or=50% luminal stenosis) in 19% (93). Eight percent (n = 39) had >or=1 major nondiagnostic coronary artery segment. Follow-up identified 21 patients with myocardial infarction (MI) in the significant obstructive CAD and nondiagnostic group. No patients with either normal coronary arteries or nonobstructive disease experienced an MI during follow-up. The 40-month event-free survival was 100% for both the normal and nonobstructive disease groups, 97.5% for the nondiagnostic study group, and 79% for the group with obstructive CAD. After adjustment for age, sex, diabetes mellitus, hypertension, hypercholesterolemia, and baseline coronary artery calcium (CAC), a stepwise multivariable model (Cox regression) showed that obstructive CAD was an independent predictor of cardiac events and had significant incremental value over clinical risk factors and CAC (HR = 16.6; 95% CI, 4.9-55.2; P = 0.0001). CONCLUSION: In symptomatic patients with an intermediate likelihood of CAD referred for CTA, normal coronary arteries or nonobstructive CAD portends an excellent prognosis. The finding of obstructive CAD identifies patients at higher risk of subsequent MI, independent of cardiovascular risk factors and coronary artery calcium.

Relations between digital thermal monitoring of vascular function, the Framingham risk score, and coronary artery calcium score.

BACKGROUND: Digital thermal monitoring (DTM) of vascular function was shown to correlate with the presence of known coronary artery disease (CAD). OBJECTIVE: We evaluated whether DTM can identify at-risk, asymptomatic patients with significant coronary artery calcium (CAC) or increased Framingham risk score (FRS). METHODS: Two hundred thirty-three consecutive asymptomatic subjects (58 +/- 11 years; 62% men) without known CAD underwent DTM, CAC, and FRS calculation. DTM measurements were obtained during and after a 5-minute suprasystolic arm-cuff occlusion. After cuff-deflation temperature rebound (TR) and area under the temperature curve (AUC) were measured and correlated with FRS and CAC. RESULTS: TR was lower in patients with FRS > 20% and CAC >or= 100 as compared with FRS < 10% and CAC < 10, respectively (P < 0.05). After adjustment for age, sex, and traditional cardiac risk factors, the odds ratio of the lowest compared with the upper 2 tertiles of TR was 3.96 for FRS >or= 20% and 2.37 for CAC >or= 100 compared with low-risk cohorts. The area under the receiver operating characteristic (ROC) curve to predict CAC >or= 100 increased significantly from 0.66 for FRS to 0.79 for TR to 0.89 for TR + FRS. CONCLUSIONS: Vascular dysfunction measured by DTM strongly correlates with FRS and CAC independent of age, sex, and traditional cardiac risk factors and was superior to FRS for the prediction of significant CAC.

Expert review on coronary calcium.

While there is no doubt that high risk patients (those with >20% ten year risk of future cardiovascular event) need more aggressive preventive therapy, a majority of cardiovascular events occur in individuals at intermediate risk (10%-20% ten year risk). Accurate risk assessment may be helpful in decreasing cardiovascular events through more appropriate targeting of preventive measures. It has been suggested that traditional risk assessment may be refined with the selective use of coronary artery calcium (CAC) or other methods of subclinical atherosclerosis measurement. Coronary calcification is a marker of atherosclerosis that can be quantified with the use of cardiac CT and it is proportional to the extent and severity of atherosclerotic disease. The published studies demonstrate a high sensitivity of CAC for the presence of coronary artery disease but a lower specificity for obstructive CAD depending on the magnitude of the CAC. Several large clinical trials found clear, incremental predictive value of CAC over the Framingham risk score when used in asymptomatic patients. Based on multiple observational studies, patients with increased plaque burdens (increased CAC) are approximately ten times more likely to suffer a cardiac event over the next 3-5 years. Coronary calcium scores have outperformed conventional risk factors, highly sensitive C-reactive protein (CRP) and carotid intima media thickness (IMT) as a predictor of cardiovascular events. The relevant prognostic information obtained may be useful to initiate or intensify appropriate treatment strategies to slow the progression of atherosclerotic vascular disease. Current data suggests intermediate risk patients may benefit most from further risk stratification with cardiac CT, as CAC testing is effective at identifying increased risk and in motivating effective behavioral changes. This article reviews information pertaining to the clinical use of CAC for assessing coronary atherosclerosis as a useful predictor of coronary artery disease (CAD) in certain population of patients.

Prevalence of obstructive coronary artery disease in an outpatient cardiac CT angiography environment.

PURPOSE: To determine the prevalence of significant obstructive disease and non-diagnostic studies using coronary computed tomographic angiography (CTA) in an outpatient environment, to establish if CTA could help avoid unnecessary diagnostic cardiac catheterizations. METHODS: We evaluated all cases consecutively performed in our outpatient CTA laboratory seen over one year with an indication that could warrant a cardiac catheterization to establish the presence or absence of coronary artery disease (CAD). Excluded were patients without established indications for cardiac catheterization and those with known CAD (i.e.- prior myocardial infarction, revascularization). Four hundred and ninety-three (493) CTA case studies were included for the analysis. Patients were classified as normal (no luminal irregularities seen), non-obstructive coronary disease (<50% stenosis), significant obstructive coronary disease (>50% stenosis), or a non-diagnostic study. We assumed that all patients assigned to the obstructive CAD group and the non-diagnostic study group would require a cardiac catheterization. In the remaining two groups, a cardiac catheterization would not be necessary for diagnosis or treatment. RESULTS: Of the 493 index cases evaluated, 157 (32%) cases were reported to be normal, 204 patients were classified as having non-obstructive disease (41%), 93 patients were defined to have obstructive CAD (19%), and 39 cases were inconclusive (8%). Thus, in 27% of the study population, a conventional coronary angiography would be indicated to clarify the diagnosis or provide definitive disease severity for subsequent revascularization. CONCLUSION: Among ambulatory patients referred for CT angiography with symptoms or positive (or equivocal) cardiac stress tests, 73% of patients were found to have either normal coronary arteries or non-obstructive disease. Given the high negative predictive power of cardiac CTA (93-99%), these patients most likely would not require subsequent invasive coronary angiography. A strategy of selective cardiac catheterization may substantially decrease unnecessary diagnostic cardiac catheterizations and reduce health care expenses.

Cardiac CT angiography (CTA) and nuclear myocardial perfusion imaging (MPI)-a comparison in detecting significant coronary artery disease.

RATIONALE AND OBJECTIVES: Endowed with sufficient diagnostic accuracy, electron beam computed tomography angiography (CTA) is being increasingly used to evaluate coronary arteries. However, data on direct comparisons with nuclear myocardial perfusion studies are limited. In this study, we sought to compare the accuracies of CTA and myocardial perfusion imaging (MPI) for identifying symptomatic patients with hemodynamically significant obstructive coronary artery disease (CAD). MATERIALS AND METHODS: In a single-center study, symptomatic outpatients who were scheduled for cardiac catheterization were prospectively enrolled. Only patients with exertional angina or dyspnea were included. After fulfilling the inclusion criteria, 30 patients were enrolled in the study (mean age 54 +/- 9 years and 70% males). Patients underwent MPI, CTA including coronary artery calcification (CAC) measure, and invasive coronary angiography for evaluation of obstructive coronary artery disease. Significant CAD was defined as >50% left main artery stenosis or >70% stenosis of any other epicardial vessel by invasive angiography. The sensitivities, specificities and predictive values of MPI, CAC, and CTA were analyzed per patient RESULTS: CTA demonstrated significant higher sensitivity than MPI (95% vs. 81%, P < .05). CTA demonstrated significantly higher specificity than both MPI (89% versus 78%, P = .04) and CAC (56%, P = .002). CTA also performed better in a per-vessel analysis (sensitivity 94%, specificity 96%) than both nuclear and CAC. There were no significant differences between the sensitivities and specificities of MPI and CAC. CONCLUSION: CTA accurately detects obstructive CAD in symptomatic patients and may be more accurate than MPI or CAC assessment. Larger studies in a more diverse population are needed.

Coronary anomalies by cardiac computed tomographic angiography.

BACKGROUND: Early identification of an anomalous coronary anatomy is quite relevant because of the increased incidence of sudden cardiac death or related symptoms of myocardial ischemia in the patients. Invasive coronary angiography (ICA) is not only invasive, but expensive, and cannot always adequately provide the required information about the abnormal coronary anatomy. Cardiac computed tomographic angiography (CTA) is a robust noninvasive imaging modality that has several clinical applications and is now being used increasingly in practices across the nation. It not only provides high-resolution anatomical information of the coronary artery tree but also helps define other aspects of the cardiovascular anatomy, be it normal or abnormal. HYPOTHESIS: This study sought to determine the clinical role played by CTA in the evaluation of different types of coronary arterial anomalies by reviewing CTA studies since 1997. METHODS: We reviewed 6,089 case studies of contrast CTA conducted at our institution. There were 53 coronary anomalies in 39 patients (0.64%). RESULTS: Computed tomographic angiography correctly identified the course of coronary arteries in all cases. CONCLUSION: The results of this study support the use of CTA as a safe and effective noninvasive imaging modality for defining coronary arterial anomalies in an appropriate clinical setting, providing detailed three-dimensional anatomic information that may be difficult to obtain with invasive angiography.

Noninvasive gadolinium-enhanced three dimensional computed tomography coronary angiography.

RATIONALE AND OBJECTIVES: Although the use of gadolinium (Gd)-based contrast agents for angiographic studies of abdominal aorta, renal vasculature, and digital subtraction angiography has been reported, no studies have shown their diagnostic efficacy and image quality in coronary computed tomography angiography (CTA). The aim of this study is to evaluate the image quality of Gd-based contrast agents during coronary CTA. MATERIALS AND METHODS: A phantom study was done to evaluate the attenuation of serial dilutions of Gd and iodinated agents. This study was done on a 64-slice multirow detector CT (MDCT) scanner and e-speed scanner and CT attenuation Hounsfield units (CTHU) were compared. We evaluated 35 consecutive patients who underwent Gd-enhanced CTA. CTHU of aorta was measured at first, mid, and lowest slice levels with and without contrast administration. The image quality was graded on the basis of visualization of the coronary arteries (scale I-III; III demonstrating diagnostic image quality of the distal-most vessels). In a substudy, four patients with borderline renal insufficiency underwent CTA using Gd and iodinated contrast agents admixed in a 50:50 ratio. RESULTS: The phantom study showed that enhancement of various dilutions of Gd and iodine resulted in near identical CTHU with both e-speed and 64-slice scanners (r(2) > or = 0.997). Mean CTHU with contrast at the top slice was 116 HU, at middle slice was 125 HU, and at the lower slice was 93 (111.14 +/- 22). Quality evaluation showed 2 grade III, 9 grade II, and 24 grade I images (average quality of images 1.35). Mean CTHU was 222. CONCLUSION: Gd-enhanced contrast medium provides adequate enhancement of coronary vasculature, allowing for diagnostic evaluation of coronary arteries with new CT systems. Use of newer generations of multirow detector CT scanners should further enhance the quality of images.

Computed tomographic cardiovascular imaging.

Over the last decade, there has been increased recognition that atherosclerosis imaging adds greatly to the ability to identify patients at high risk for cardiac events. Technologies such as electron beam computed tomography and carotid intimal media thickness have contributed significantly to our understanding of the prevalence of preclinical atherosclerosis and its consequences. Current data suggest that elevated calcium scores are predictive of future cardiac events, independently and incrementally to traditional cardiac risk factors. The approximate predictive power is 10-fold for scores > 100, based upon current studies now reported. Guidelines and policy toward these modalities have shifted, with increased recognition of the importance among experts in cardiology, lipidology, and preventive medicine. Because most adverse events related to atherosclerosis occur in individuals at an intermediate risk, data suggest that it will be most cost-effective to concentrate screening efforts on this group of patients. This article reviews the current understanding of the value of coronary artery calcium screening in asymptomatic and symptomatic patients. Accurate measurement of subclinical coronary atherosclerosis should significantly improve the accuracy of global cardiovascular risk prediction, and allow for tracking of atherosclerosis burden, as well as better prediction of future cardiovascular events. Finally, by identifying high-risk patients, CAC may help select those patients who would benefit most from additional testing (e.g., non-invasive stress imaging) and intensification of medical therapy; CAC should have a significant impact on early detection and management of CAD.

Chloroquine-induced cardiomyopathy-echocardiographic features.

A 61-year-old woman with a 30-year history of systemic lupus erythematosus treated with chloroquine sulfate presented with complete heart block, congestive heart failure, and findings of restrictive cardiomyopathy on echocardiogram. Thickening of mitral, aortic, and tricuspid valves along with mild to moderate valve regurgitation was also present. Magnetic resonance imaging showed increased gadolinium uptake in the interventricular septum and the left ventricular lateral wall. Endomyocardial biopsy specimen showed marked myocardial cytoplasmic vacuolation and extensive myelin figures. Seven months after discontinuation of chloroquine, she showed significant clinical improvement and reversal of cardiomyopathy on echocardiography. This is the first case report describing a cardiomyopathy with prolonged use of chloroquine involving the conduction system, cardiac valves, and the myocardium with reversal on discontinuation of the drug.

Vasa vasorum imaging: a new window to the clinical detection of vulnerable atherosclerotic plaques.

Complications of vulnerable atherosclerotic plaques (rupture, luminal and mural thrombosis, intraplaque hemorrhage, rapid progression to stenosis, spasm, and so forth) lead to heart attacks and strokes. It remains difficult to identify what plaques are vulnerable to these complications. Despite recent developments such as thermography, spectroscopy, and magnetic resonance imaging, none of them is approved for clinical use. Intravascular ultrasound (IVUS), a relatively old yet widely available clinical tool for guiding intracoronary procedures, is increasingly used for characterization of atherosclerotic plaques. However, inability of IVUS in measuring plaque activity limits its value in detection of vulnerable plaques. In this review, we present new information suggesting that microbubble contrast-enhanced IVUS can measure activity and inflammation within atherosclerotic plaques by imaging vasa vasorum density. An increasing body of evidence indicates that vasa vasorum density may be a strong marker for plaque vulnerability. We suggest that a combination of structural assessment (cap thickness, lipid core, calcification, etc) and vasa vasorum density imaging by IVUS can serve as the most powerful clinically available tool for characterization of vulnerable plaques. Due to space limitations, all IVUS images and movies are posted on the website of the Ultimate IVUS Collaborative Project: http://www.ultimateivus.com.

Thermography basket catheter: in vivo measurement of the temperature of atherosclerotic plaques for detection of vulnerable plaques.

We have developed an intravascular thermography basket catheter to measure the temperature of the vessel wall to locate foci of inflammation. Our 3 Fr thermography basket catheter is a thermocouple-based catheter made of a nitinol expandable and externally controllable basket system loaded with nine small and flexible built-in thermosensors. It is equipped with real-time data acquisition software with a thermal resolution of 0.0001 degrees C and a sampling rate of 20 readings per second. In 10 inbred cholesterol-fed dogs with femoral (but not carotid) atherosclerosis, we found foci of warmth on the surface of atherosclerotic but not disease-free regions (P < 0.05). Marked temperature heterogeneity was also observed in the aortas of atherosclerotic Watanabe rabbits but not in normal rabbits. The catheters showed satisfactory accuracy, reproducibility, and safety. If confirmed in further studies, it has the potential to be utilized in detection of vulnerable plaques.