Hussain Isma'eel

Prevalence and non-invasive predictors of left main or three-vessel coronary disease: evidence from a collaborative international meta-analysis including 22 740 patients

Background Left main disease (LMD) and three-vessel disease (3VD) have important prognostic value in patients with coronary artery disease. However, uncertainties still exist about their prevalence and predictors in patients with acute coronary syndrome (ACS) and also in patients with stable coronary disease. Thus the aim of this study was to perform an international collaborative systematic review and meta-analysis to appraise the prevalence and predictors of LMD and 3VD. Methods Medline/PubMed were systematically searched for eligible studies published up to 2010, reporting multivariate predictors of LMD or 3VD. Study features, patient characteristics, and prevalence and predictors of LMD and 3VD were abstracted and pooled with random-effect methods (95% CIs). Results 17 studies (22 740 patients) were included, 11 focusing on ACS (17 896 patients) and six on stable coronary disease (4844 patients). In the ACS subgroup, LMD or 3VD occurred in 20% (95% CI 7.2% to 33.4%), LMD in 12% (95% CI 10.5% to 13.5%), and 3VD in 25% (95% CI 23.1% to 27.0%). Heart failure at admission and extent of ST-segment elevation in lead aVR on 12-lead ECG were the most powerful predictors of LMD or 3VD. In the stable disease subgroup, LMD or 3VD was found in 36% (95% CI 18.5% to 48.8%), with the most powerful predictors being transient ischaemic dilation during the imaging stress test, extent of ST-segment elevation in aVR and V1 during the stress test, and hyperlipidaemia. Conclusions This meta-analysis demonstrated that severe coronary disease—that is, LMD or 3VD—is more common in patients with ACS or stable coronary disease than generally perceived, and that simple and low-cost tools may help in the selection of the most appropriate therapeutic approach.

Measurement of Thoracic Bone Mineral Density with Quantitative CT

PURPOSE To create standard thoracic bone mineral density (BMD) values for patients undergoing cardiac computed tomography (CT) by using thoracic quantitative CT and to compare these BMDs (in a subpopulation) with those obtained by using lumbar spine quantitative CT. MATERIALS AND METHODS The institutional review board approved this HIPAA-compliant study. A total of 9585 asymptomatic subjects (mean age, 56 years; age range, 30-90 years) who underwent coronary artery calcium scanning, including 4131 women, were examined. Patients with vertebral deformities or fractures were excluded. Six hundred forty-four subjects (322 of whom were female) also underwent lumbar quantitative CT. The mean thoracic vertebral BMDs for both sexes were reported separately in a subgroup of subjects aged 30 years and in 29 age-based subgroups in 2-year intervals from ages 30 to 90 years. The formulas used to calculate the female T score (T(f)) and the male T score (T(m)) on the basis of thoracic quantitative CT measurements were as follows: T(f) = (BMD(im) - 222)/36, and T(m) = (BMD(im) - 215)/33, where BMD(im) is the individual mean BMD. Comparisons between thoracic quantitative CT and lumbar quantitative CT measurements, as well as analyses of intraobserver, interobserver, and interscan variability, were performed. RESULTS The young-subgroup mean BMD was 221.9 mg/mL ± 36.2 (standard deviation) for the female subjects and 215.2 mg/mL ± 33.2 for the male subjects. The mean thoracic BMDs for the female and male subjects were found to be 20.7% higher and 17.0% higher, respectively, than the values measured with lumbar quantitative CT (P < .001 for both comparisons). A significant positive association between the thoracic and lumbar quantitative CT measurements (r > 0.85, P < .001) was found. Intraobserver, interobserver, and interscan variabilities in thoracic quantitative CT measurements were 2.5%, 2.6%, and 2.8%, respectively. CONCLUSION There was a significant association between the mean thoracic and lumbar BMDs. Therefore, standard derived measurements (young-subgroup BMD ± standard deviation) based on these data can be used with thoracic CT images to estimate the bone mineral status.

Impact of coronary artery calcium progression and statin therapy on clinical outcome in subjects with and without diabetes mellitus.

Coronary artery calcium (CAC) is a marker of atherosclerosis, and CAC progression is independently associated with all-cause mortality in the general population but not convincingly in subjects with diabetes mellitus (DM). The aim of this study was to ascertain the differences in the rates of CAC progression, the effect of statin therapy, and all-cause mortality in subjects with and without DM. The study group consisted of 296 asymptomatic subjects with type 2 DM and 300 controls (mean age 59 ± 6 years, 29% women) who underwent baseline and follow-up CAC scans within a 2-year interval. Absolute annual CAC score change, percentage annual CAC progression(ΔCAC%), event-free survival, and the effect of statin therapy on survival were all assessed. The mean follow-up duration was 56 ± 11 months. Absolute annual CAC score change was 81 ± 10 in subjects with DM and 34 ± 5 in controls (p = 0.0001). Percentage annual CAC progression was 29 ± 9% in subjects with DM and 10 ± 7% in controls (p = 0.0001). The hazard ratios of death in 3 groups of subjects with DM compared to controls without DM were 1.88 (95% confidence interval [CI] 1.51 to 2.36, p = 0.0001) for ΔCAC of 10% to 20%, 2.29 (95% CI 1.56 to 3.38, p = 0.0001) for ΔCAC of 21% to 30%, and 6.95 (95% CI 2.23 to 11.53, p = 0.0001) for ΔCAC >30%, all compared to ΔCAC <10%. The adjusted hazard ratios of all-cause mortality in subjects receiving compared to those not receiving statin therapy were 0.29 (95% CI 0.13 to 0.56, p = 0.001) in those without DM and without CAC progression, 0.51 (95% CI 0.21 to 0.73, p = 0.001) in those with DM and without CAC progression, and 0.71 (95% CI 0.25 to 0.91, p = 0.003) in those without DM and with CAC progression, with all 3 groups compared to 1.0 (reference) in those with DM, with CAC progression and without statin therapy. In conclusion, CAC progression was greater and event-free survival lower in patients with DM compared to controls in proportion to the extent of CAC progression. These results suggest that CAC progression is an independent predictor of all-cause mortality in patients with DM.

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.

Trabecular Bone Mineral Density Measurement Using Thoracic and Lumbar Quantitative Computed Tomography

PURPOSE To evaluate the agreement of bone mineral density (BMD) between lumbar (L) and individual thoracic (T) vertebrae and identify a standard thoracic spine level for BMD assessment in cardiac computed tomography (CT) images. MATERIALS AND METHODS Three hundred subjects who underwent simultaneous chest and abdomen CT scans for clinical indications were included. A calibration phantom that extended from the first thoracic spine (T(1)) to the fifth lumbar (L(5)) was employed. Vertebral BMD were measured by QCT 5000 and NVivo systems. The association between three consecutive lumbar (L1-L3) and thoracic BMD (3T, initiation site equivalent to left main coronary caudally) was evaluated. RESULTS There was a gradual decrease in BMD values from T(1) to L(3,) subsequently increasing in L(4) and L(5) in both genders. When stratified by gender, 3T BMD was significantly higher versus L(1-3) BMD (156.9 versus 141.9vmg/cm(3), P < .001) for women as well as for men (164.8 versus 151.0 mg/cm(3), P < .001). There is good correlation between 3T and L(1-3) BMD, the Pearsons correlation coefficients are 0.91 and 0.93 for women and men, respectively. We further analyzed the associations between L(1-3) and any individual spine of T(1)-L(5) and similar relationships were observed (r value, 0.62-0.98). The intraobserver, interobserver, and interscan variation measurement of thoracic quantitative CT was 2.5 (1.0, 95% CI 0.099-1.004); 2.6 (1.0, 95CI% 0.992-1.007), and 2.8% (1.0,95% 0.0994-1.008), respectively. CONCLUSION The 3T BMD was highly correlated with L(1-3) BMD. Thoracic BMD can be measured during cardiac and lung CT imaging without need for additional participant burden or radiation dose. This highly reproducible methodology is actively being applied to large cohort studies to evaluate the prevalence of osteoporosis and track BMD over time.

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.

Determinants of left main calcifications in a cohort of 2136 diabetes patients.

INTRODUCTION Left main (LM) calcification has been shown to be an independent predictor of mortality. Diabetes accelerates atherosclerosis and coronary artery calcification (CAC). In this study we aimed to describe the predictors of LM calcification in diabetes patients. METHODS From a database of >25,000 patients who have undergone CAC scanning at our institution, consecutive diabetic patients (n=2136) were evaluated for demographic data, CAC scores and coronary risk factors. RESULTS In our cohort 29.1% of patients had LM CAC. Of the classical atherosclerosis risk factors, in binary regression analysis, only age (OR 1.03 [1.017-1.043]), male gender (OR 1.59; p<0.05), hypertension (OR 1.73; p<0.05), and CAC score (OR 1.001; p<0.05) were found to be independently associated with LM disease. CONCLUSION The prevalence of LM CAC is high amongst diabetics (29.1%); associated with increased age, HTN and male sex.

DIAGNOSTIC ACCURACY OF 64-SLICE COMPUTED TOMOGRAPHY ANGIOGRAPHY IN DISTINGUISHING ISCHEMIC FROM NONISCHEMIC CARDIOMYOPATHY

The use of Cardiac Computed Tomography Angiography (CCTA) to distinguish ischemic vs non-ischemic etiology in newly diagnosed heart failure patients with low to intermediate probability of coronary artery disease (CAD) is an appropriate indication (appropriateness score = 7) according to the current