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Background: Total plaque score (TPS) on coronary computed tomography angiography (CCTA) has been validated as a surrogate measure of coronary artery disease (CAD) burden and is prognostic. We propose a novel measure, percentage TPS adjusted to age (%TPS/age), that may reflect vascular age and potentially more rapidly progressive atherosclerosis and evaluate its potential prognostic value. Methods: %TPS/age was calculated for consecutive patients prospectively enrolled into our institutional CCTA registry and evaluated for primary composite outcome of cardiac death, nonfatal myocardial infarction, and late revascularization. Results: Of 1896 patients identified (mean age 57.7 ± 11.4 years, 50.1% male, median follow-up 18.6 months [interquartile range: 15.3, 32.4]), 552 (29%) had %TPS/age = 0 (no atherosclerosis), with 1 (0.2%) primary outcome observed (annual event rate [AER] = 0.1%). Two events (0.4%, AER = 0.3%) were observed in %TPS/age < 0.314 category, 22 (5.0%, AER = 2.2%) in %TPS/age 0.314 to 0.699 category, and 54 (12.0%, AER = 5.7%) in %TPS/age ≥ 0.700 category. After adjusting for clinical predictors and obstructive CAD, higher %TPS/age category was associated with hazard ratio 1.95 (1.31-2.88, P < .001) for primary outcome on multivariable analysis, Harrell-C-Statistic 0.87 (confidence interval 95%: 0.84-0.90), and net reclassification improvement of 0.71 (P < .001). Conclusion: %TPS/Age has incremental prognostic value to traditional risk factors and CCTA measures of CAD and improves evaluation of burden of coronary atherosclerosis and clinical risk. [ABSTRACT FROM AUTHOR]

Low-attenuation plaques (LAPs) are associated with an increased risk of cardiovascular mortality and morbidity. South Asians experience poorer cardiovascular outcomes compared to Caucasian populations. We hypothesised that South Asian population has a higher prevalence of LAP compared to Caucasians and this difference predicts major adverse cardiovascular events. 72 Caucasian and 72 Morise score-matched South Asian patients were identified from a cardiac computed tomography angiography (CCTA) registry. Coronary artery plaque subtypes in proximal major epicardial and left main arteries were analysed from CCTA images using pre-determined attenuation ranges in Hounsfield units (HUs): 1 to 30 HU (low attenuation), 31 to 70 HU (intermediate attenuation), 71 to 150 HU (high attenuation), and mean coronary lumen + 2 standard deviations to 1000 HU (calcified). For each analysis, data comparison was performed for plaque volumes after normalising for the corresponding coronary artery outer vessel wall volume. The baseline characteristics and total plaque score of the two cohorts were similar. There were no statistically significant differences in low, intermediate, and high- attenuation, or calcified normalised plaque volumes between Caucasian and Morise score-matched South Asian cohorts. After a mean follow up of 32 months, major adverse cardiovascular events were similar between Caucasians and South Asians. In a Morise score-matched ethnicity study, we found no significant differences in plaque subtypes including LAP in South Asians compared to a Caucasian cohort. Other factors accounting for poor outcomes in South Asians should be investigated.

Introduction: Aortic valve calcification (AVC) has been associated with major adverse cardiovascular events and all-cause mortality. We sought to develop and validate a method to quantify AVC using coronary CT angiography (CTA)., Methods: Of 59 patients who underwent both non-contrast and contrast enhanced coronary CTA, 25 patients served as the derivation cohort and 34 patients served as the validation cohort. For non-contrast enhanced CT, quantification of AVC was performed using the Agatston method for coronary artery calcification (CAC). For contrast enhanced coronary CTA, a region of interest (ROI) was placed in the ascending aorta and the mean aortic attenuation value (HU Aorta ) and standard deviation (SD) were measured. Using a calcium threshold of mean HU Aorta  + 2SD, the AVC CTA was calculated. All other Agatston score parameters (weighting factors and area calculations) remained unchanged., Results: In the derivation cohort, the correlation between AVC CAC and AVC CTA was excellent (r = 0.982). Using the line of best fit, a correction factor was calculated enabling the conversion of AVC CTA results to a AVC CAC equivalent (AVC Corrected  = 1.868 × AVC CTA ). Using this correction in the validation cohort, the correlation and agreement between AVC CAC and AVC Corrected were good (ICC = 0.939; 95% CI: 0.881-0.969; kappa = 0.700; 95% CI: 0.469-0.931)., Conclusion: The quantification of AVC Corrected using contrast enhanced CTA is feasible using a systematic approach with very good reliability and good agreement with AVC CAC . Larger-scale validation studies are needed to determine whether the use of AVC CAC can be eliminated in favour of AVC Corrected ., (Copyright © 2017 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.)

Unlabelled: Recent studies have shown that vasodilator-induced ischemic electrocardiographic (ECG) changes have incremental prognostic value over normal SPECT myocardial perfusion imaging (MPI) and identify patients at higher risk for cardiac events. The prognostic value of vasodilator-induced ischemic ECG changes in the setting of normal PET MPI has yet to be determined. We sought to determine the prognostic importance of dipyridamole-induced ischemic ECG changes in patients with normal 82Rb PET myocardial perfusion images., Methods: Between 2000 and 2003, 2,029 consecutive patients undergoing dipyridamole stress 82Rb PET at the University of Ottawa Heart Institute were evaluated. Patients with normal PET MPI and interpretable ECGs were enrolled. Electrocardiograms were assessed for ST depression or elevation and patients were categorized into those with and without dipyridamole-induced ischemic ECG changes. Images were graded using the 17-segment model. Follow-up information was obtained by telephone interview, from hospital records, or from treating physicians. All cardiac events (cardiac death, nonfatal myocardial infarction [MI], percutaneous coronary intervention, coronary artery bypass grafting, or angiography) were verified with hospital records., Results: Of the 629 enrolled patients with normal PET MPI, 72 patients had dipyridamole-induced ischemic ECG changes. There was no significant difference between the 2 groups in the combined endpoint (cardiac death, nonfatal MI, and revascularization) at follow-up (mean +/- SD, 27.1 +/- 13 mo). There were no cardiac deaths in either group. One (1.4%) patient with ischemic ECG changes had a nonfatal MI (0.6% annual event rate). Two (2.8%) patients with ischemic ECG changes required revascularization compared with 11 (2.0%) in the nonischemic ECG group., Conclusion: Normal 82Rb PET confers an excellent prognosis regardless of dipyridamole-induced ST depression.