The diagnostic accuracy of 64-detector cardiac computed tomography compared with stress nuclear imaging in patients undergoing invasive cardiac catheterization.

OBJECTIVE: The aim of this study was to evaluate the diagnostic accuracy of nuclear stress imaging as compared with noninvasive coronary artery imaging using 64-detector row cardiac computed tomography. BACKGROUND: Compared with invasive coronary angiography, multidetector row cardiac computed tomographic angiography (CTA) has shown promise in the accurate detection of coronary stenosis. Myocardial perfusion imaging (MPI) using single photon emission computed tomography is an established method for noninvasively assessing the functional significance of coronary stenosis. This study compared the accuracy of CTA and that of MPI in the detection of relevant lesions of coronary arteries. METHODS: One hundred twenty-two symptomatic patients (77% males) with cardiac catheterization who also underwent MPI and CTA evaluations within 6 months at 2 centers were included. Comparison of CTA for lesions causing greater than 50% and greater than 70% coronary narrowing versus respective lesions on invasive cardiac catheterization (IC) was performed. Similarly, comparison of MPI findings with greater than 50% and greater than 70% lesions on IC was done. RESULTS: The per-patient sensitivity, specificity, and positive and negative predictive values in detecting greater than 50% coronary lesions on IC for CTA were 98.9%, 74.2%, 91.8%, and 95.8%, respectively; and for MPI, 56%, 38.7%, 72.9%, and 23%, respectively. The sensitivity, the specificity, and the positive and negative predictive values in detecting greater than 70% coronary lesions on IC for CTA were 89.7%, 86.4%, 92.1%, and 82.6%, respectively; and for MPI, 57.7%, 43.2%, 64.3%, and 36.5%, respectively. The prevalence of significant coronary artery disease on cardiac catheterization was 74.6% for greater than 50% stenosis and 63.9% for greater than 70% stenosis. CONCLUSIONS: Compared with MPI, CTA provided important information and identified significant lesions in symptomatic intermediate- to high-risk patients. Cost-effective and prospective multicentered studies, currently underway, are needed to further establish the best use of these diagnostic tests in the evaluation of coronary artery disease.

Relation of oxidative biomarkers, vascular dysfunction, and progression of coronary artery calcium.

The relation between oxidative stress and coronary artery calcium (CAC) progression is currently not well described. The present study evaluated the relation among the biomarkers of oxidative stress, vascular dysfunction, and CAC. Sixty asymptomatic subjects participated in a randomized trial evaluating the effect of aged garlic extract plus supplement versus placebo and underwent measurement of CAC. The postcuff deflation temperature-rebound index of vascular function was assessed using a reactive hyperemia procedure. The content of oxidized phospholipids (OxPL) on apolipoprotein B-100 (apoB) particles detected by antibody E06 (OxPL/apoB), lipoprotein(a), IgG and IgM autoantibodies to malondialdehyde-low-density lipoprotein and apoB-immune complexes were measured at baseline and after 12 months of treatment. CAC progression was defined as an annual increase in CAC >15%. Vascular dysfunction was defined according to the tertiles of temperature-rebound at 1 year of follow-up. From baseline to 12 months, a strong inverse correlation was noted between an increase in CAC scores and increases in temperature-rebound (r(2) = -0.90), OxPL/apoB (r(2) = -0.85), and lipoprotein(a) (r(2) = -0.81) levels (p <0.0001 for all). The improvement in temperature-rebound correlated positively with the increases in OxPL/apoB (r(2) = 0.81, p = 0.0008) and lipoprotein(a) (r(2) = 0.79, p = 0.0001) but inversely with autoantibodies to malondialdehyde-low-density lipoprotein and apoB-immune complexes. The greatest CAC progression was noted with the lowest tertiles of increases in temperature-rebound, OxPL/apoB and lipoprotein(a) and the highest tertiles of increases in IgG and IgM malondialdehyde-low-density lipoprotein. In conclusion, the present results have documented a strong relation among markers of oxidative stress, vascular dysfunction, and progression of coronary atherosclerosis. Increases in OxPL/apoB and lipoprotein(a) correlated strongly with increases in vascular function and predicted a lack of progression of CAC.

Detection of aortic regurgitation with 64-slice multidetector computed tomography (MDCT).

RATIONALE AND OBJECTIVES: To determine the diagnostic accuracy of 64-row multidetector cardiac computed tomography (MDCT) in detecting aortic regurgitation (AR) on prospectively acquired images with trans-thoracic echocardiography (TTE) as a reference standard. MATERIALS AND METHODS: Forty-three consecutive patients underwent MDCT and TTE. AR was defined on MDCT images acquired at 75% phase of R-R interval as the lack of aortic cusps coaptation. The maximum regurgitant orifice area (ROA) was planimetered and compared to TTE. RESULTS: All 29 patients with AR on TTE were correctly identified by MDCT. The sensitivity, specificity, positive predictive value, and negative predictive value of MDCT were 100%, 85.7%, 93.5%, and 100%, respectively. Sixteen, nine, and four patients were found to have mild, moderate, and severe AR on TTE, respectively. The corresponding ROA by MDCT were 3.25 +/- 1.04 mm(2), 4.16 +/- 1.19 mm(2), and 11.30 +/- 6.13 mm(2), respectively. CONCLUSION: MDCT data acquired for the coronary artery evaluation can be used for the detection of aortic regurgitation with high diagnostic accuracy without additional scanning or radiation and can support appropriate referral for TTE.