Ronald P. Karlsberg

SCCT guidelines for the interpretation and reporting of coronary computed tomographic angiography

The increasing use of coronary computed tomographyangiography(CCTA)requirestheestablishmentofstandardsmeant to ensure reliable practice methods and qualityoutcomes.TheSocietyofCardiovascularComputedTomog-raphy Guidelines Committeewas formed to develop recom-mendations for acquiring, interpreting, and reporting thesestudies in a standardized fashion. Indications and contrain-dicationsforspecificservicesorproceduresarenotincludedin the scope of these documents. These recommendationswere produced as an educational tool for practitioners toimprove the diagnostic care of patients, in the interest ofdevelopingsystematicstandardsofpracticeforCCTAbasedon the best available data or broad expert consensus. Due tothe highly variable nature of individual medical cases, anapproachtointerpretationorreportingthatdiffersfromtheseguidelinesmayrepresentanappropriatevariationbasedonalegitimate assessment of an individual patient’s needs.The Society of Cardiovascular Computed TomographyGuidelinesCommitteemakeseveryefforttoavoidanyactualorpotentialconflictsofinterestthatmightariseasaresultofan outside relationship or a personal interest of a member ofthe Guidelines Committee or either of its Writing Groups.Specifically, all members of the Guidelines Committee andof both Writing Groups are asked to provide disclosurestatementsofallsuchrelationshipsthatmightbeperceivedasrealorpotentialconflictsofinterestrelevanttothedocumenttopic. The relationships with industry information for Com-mittee members and Writing Group members are published

Coronary Computed Tomographic Angiography as a Gatekeeper to Invasive Diagnostic and Surgical Procedures : Results From the Multicenter CONFIRM (Coronary CT Angiography Evaluation for Clinical Outcomes: An International Multicenter) Registry

OBJECTIVES This study sought to examine patterns of follow-up invasive coronary angiography (ICA) and revascularization (REV) after coronary computed tomography angiography (CCTA). BACKGROUND CCTA is a noninvasive test that permits direct visualization of the extent and severity of coronary artery disease (CAD). Post-CCTA patterns of follow-up ICA and REV are incompletely defined. METHODS We examined 15,207 intermediate likelihood patients from 8 sites in 6 countries; these patients were without known CAD, underwent CCTA, and were followed up for 2.3 ± 1.2 years for all-cause mortality. Coronary artery stenosis was judged as obstructive when ≥50% stenosis was present. A multivariable logistic regression was used to estimate ICA use. A Cox proportional hazards model was used to estimate all-cause mortality. RESULTS During follow-up, ICA rates for patients with no CAD to mild CAD according to CCTA were low (2.5% and 8.3%), with similarly low rates of REV (0.3% and 2.5%). Most ICA procedures (79%) occurred ≤3 months of CCTA. Obstructive CAD was associated with higher rates of ICA and REV for 1-vessel (44.3% and 28.0%), 2-vessel (53.3% and 43.6%), and 3-vessel (69.4% and 66.8%) CAD, respectively. For patients with <50% stenosis, early ICA rates were elevated; over the entirety of follow-up, predictors of ICA were mild left main, mild proximal CAD, respectively, or higher coronary calcium scores. In patients with <50% stenosis, the relative hazard for death was 2.2 (p = 0.011) for ICA versus no ICA. Conversely, for patients with CAD, the relative hazard for death was 0.61 for ICA versus no ICA (p = 0.047). CONCLUSIONS These findings support the concept that CCTA may be used effectively as a gatekeeper to ICA.

Differences in Prevalence, Extent, Severity, and Prognosis of Coronary Artery Disease Among Patients With and Without Diabetes Undergoing Coronary Computed Tomography Angiography: Results from 10,110 individuals from the CONFIRM (COronary CT Angiography EvaluatioN For Clinical Outcomes): an InteRnational Multicenter Registry

OBJECTIVE We examined the prevalence, extent, severity, and prognosis of coronary artery disease (CAD) in individuals with and without diabetes (DM) who are similar in CAD risk factors. RESEARCH DESIGN AND METHODS We identified 23,643 consecutive individuals without known CAD undergoing coronary computed tomography angiography. A total of 3,370 DM individuals were propensity matched in a 1-to-2 fashion to 6,740 unique non-DM individuals. CAD was defined as none, nonobstructive (1–49% stenosis), or obstructive (≥50% stenosis). All-cause mortality was assessed by risk-adjusted Cox proportional hazards models. RESULTS At a 2.2-year follow-up, 108 (3.2%) and 115 (1.7%) deaths occurred among DM and non-DM individuals, respectively. Compared with non-DM individuals, DM individuals possessed higher rates of obstructive CAD (37 vs. 27%) and lower rates of having normal arteries (28 vs. 36%) (P < 0.0001). CAD extent was higher for DM versus non-DM individuals for obstructive one-vessel disease (19 vs. 14%), two-vessel disease (9 vs. 7%), and three-vessel disease (9 vs. 5%) (P < 0.0001 for comparison), with higher per-segment stenosis in the proximal and mid-segments of every coronary artery (P < 0.001 for all). Compared with non-DM individuals with no CAD, risk of mortality for DM individuals was higher for those with no CAD (hazard ratio 3.63 [95% CI 1.67–7.91]; P = 0.001), nonobstructive CAD (5.25 [2.56–10.8]; P < 0.001), one-vessel disease (6.39 [2.98–13.7]; P < 0.0001), two-vessel disease (12.33 [5.622–27.1]; P < 0.0001), and three-vessel disease (13.25 [6.15–28.6]; P < 0.0001). CONCLUSIONS Compared with matched non-DM individuals, DM individuals possess higher prevalence, extent, and severity of CAD. At comparable levels of CAD, DM individuals experience higher risk of mortality compared with non-DM individuals.

Effect of statin treatment on coronary plaque progression - a serial coronary CT angiography study.

OBJECTIVES Statins have been shown to reduce plaque progression using data on intravascular ultrasound, carotid intima-media thickness and coronary artery calcium scans. However, there is little data on effects of statins on plaque progression using Coronary CTA. The objective is to evaluate the effect of statin therapy on plaque progression using serial Coronary CTA (CCTA). METHODS The study included 100 consecutive patients who underwent serial Coronary CTA (mean follow up: 406 ± 92 days) for evaluation of CAD without known prior heart disease or revascularization. We performed volumetric assessment of low attenuation plaque (LAP < 30 Hounsfield units), non-calcified (NCP) and calcified plaque volumes at baseline and follow up scans for vessels >2 mm in diameter. Patients who received statins were compared to those that did not. RESULTS Total plaque progression was significantly reduced among statin user compared to non-statin users (-33.3 mm(3) ± 90.5 vs. 31.0 mm(3) ± 84.5, p = 0.0006). Statin users had significantly reduced progression of NCP volume (-47.7 mm(3) ± 71.9 vs. 13.8 mm(3) ± 76.6, p < 0.001) and significantly reduced progression of LAP volume (-12.2 mm(3) ± 19.2 vs. 5.9 mm(3) ± 23.1, p < 0.0001). When we compared for remodeling index, no statistical difference was found between the two groups (p = 0.25) and a non-significant trend toward calcium progression (29.3 mm(3) ± 67.9 vs. 10.0 mm(3) ± 53.2, p = 0.133). After adjustment for cardiovascular risk factors, mean plaque volume difference between statin and non-statin users was statistically significant for both LAP and NCP volumes (-18.1, 95% CI: -26.4, -9.8 for LAP; -101.7, 95% CI: -162.1, -41.4 for NCP; p < 0.001) respectively. CONCLUSION Statin therapy resulted in significantly lower progression of LAP and NCP plaques compared to non-statin users.

Quantitative Analysis of Myocardial Perfusion SPECT Anatomically Guided by Coregistered 64-Slice Coronary CT Angiography

Sequential testing by coronary CT angiography (CTA) and myocardial perfusion SPECT (MPS) obtained on stand-alone scanners may be needed to diagnose coronary artery disease in equivocal cases. We have developed an automated technique for MPS–CTA registration and demonstrate its utility for improved MPS quantification by guiding the coregistered physiologic (MPS) with anatomic CTA information. Methods: Automated registration of MPS left ventricular (LV) surfaces with CTA coronary trees was accomplished by iterative minimization of voxel differences between presegmented CTA volumes and motion-frozen MPS data. Studies of 35 sequential patients (26 men; mean age, 67 ± 12 y) with 64-slice coronary CTA, MPS, and available results of the invasive coronary angiography performed within 3 mo were retrospectively analyzed. Three-dimensional coronary vessels and CTA slices were extracted and fused with quantitative MPS results mapped on LV surfaces and MPS coronary regions. Automatically coregistered CTA images and extracted trees were used to correct the MPS contours and to adjust the standard vascular region definitions for MPS quantification. Results: Automated coregistration of MPS and coronary CTA had the success rate of 96% as assessed visually; the average errors were 4.3 ± 3.3 mm in translation and 1.5 ± 2.6 degrees in rotation on stress and 4.2 ± 3.1 mm in translation and 1.7 ± 3.2 degrees in rotation on rest. MPS vascular region definition was adjusted in 17 studies, and LV contours were adjusted in 11 studies using coregistered CTA images as a guide. CTA-guided myocardial perfusion analysis, compared with standard MPS analysis, resulted in improved area under the receiver-operating-characteristic (ROC) curves for the detection of right coronary artery (RCA) and left circumflex artery (LCX) lesions (0.84 ± 0.08 vs. 0.70 ± 0.11 for LCX, P = 0.03, and 0.92 ± 0.05 vs. 0.75 ± 0.09 for RCA, P = 0.02). Conclusion: Software image coregistration of stand-alone coronary CTA and MPS obtained on separate scanners can be performed rapidly and automatically, allowing CTA-guided contour and vascular territory adjustment on MPS for improved quantitative MPS analysis.

Prognostic and Therapeutic Implications of Statin and Aspirin Therapy in Individuals With Nonobstructive Coronary Artery Disease Results From the CONFIRM (Coronary CT Angiography Evaluation For Clinical Outcomes: An International Multicenter Registry) Registry

Objective— We sought to examine the risk of mortality associated with nonobstructive coronary artery disease (CAD) and to determine the impact of baseline statin and aspirin use on mortality. Approach and Results— Coronary computed tomographic angiography permits direct visualization of nonobstructive CAD. To date, the prognostic implications of nonobstructive CAD and the potential benefit of directing therapy based on nonobstructive CAD have not been carefully examined. A total of 27 125 consecutive patients who underwent computed tomographic angiography (12 enrolling centers and 6 countries) were prospectively entered into the COronary CT Angiography EvaluatioN For Clinical Outcomes: An InteRnational Multicenter (CONFIRM) registry. Patients, without history of previous CAD or obstructive CAD, for whom baseline statin and aspirin use was available were analyzed. Each coronary segment was classified as normal or nonobstructive CAD (1%–49% stenosis). Patients were followed up for a median of 27.2 months for all-cause mortality. The study comprised 10 418 patients (5712 normal and 4706 with nonobstructive CAD). In multivariable analyses, patients with nonobstructive CAD had a 6% (95% confidence interval, 1%–12%) higher risk of mortality for each additional segment with nonobstructive plaque (P=0.021). Baseline statin use was associated with a reduced risk of mortality (hazard ratio, 0.44; 95% confidence interval, 0.28–0.68; P=0.0003), a benefit that was present for individuals with nonobstructive CAD (hazard ratio, 0.32; 95% confidence interval, 0.19–0.55; P<0.001) but not for those without plaque (hazard ratio, 0.66; 95% confidence interval, 0.30–1.43; P=0.287). When stratified by National Cholesterol Education Program/Adult Treatment Program III, no mortality benefit was observed in individuals without plaque. Aspirin use was not associated with mortality benefit, irrespective of the status of plaque. Conclusions— The presence and extent of nonobstructive CAD predicted mortality. Baseline statin therapy was associated with a significant reduction in mortality for individuals with nonobstructive CAD but not for individuals without CAD. Clinical Trial Registration— URL: http://clinicaltrials.gov/. Unique identifier NCT01443637

All-cause mortality benefit of coronary revascularization vs. medical therapy in patients without known coronary artery disease undergoing coronary computed tomographic angiography: results from CONFIRM (COronary CT Angiography EvaluatioN For Clinical Outcomes: An InteRnational Multicenter Registry)

AIMS To date, the therapeutic benefit of revascularization vs. medical therapy for stable individuals undergoing invasive coronary angiography (ICA) based upon coronary computed tomographic angiography (CCTA) findings has not been examined. METHODS AND RESULTS We examined 15 223 patients without known coronary artery disease (CAD) undergoing CCTA from eight sites and six countries who were followed for median 2.1 years (interquartile range 1.4-3.3 years) for an endpoint of all-cause mortality. Obstructive CAD by CCTA was defined as a ≥50% luminal diameter stenosis in a major coronary artery. Patients were categorized as having high-risk CAD vs. non-high-risk CAD, with the former including patients with at least obstructive two-vessel CAD with proximal left anterior descending artery involvement, three-vessel CAD, and left main CAD. Death occurred in 185 (1.2%) patients. Patients were categorized into two treatment groups: revascularization (n = 1103; 2.2% mortality) and medical therapy (n = 14 120, 1.1% mortality). To account for non-randomized referral to revascularization, we created a propensity score developed by logistic regression to identify variables that influenced the decision to refer to revascularization. Within this model (C index 0.92, χ2 = 1248, P < 0.0001), obstructive CAD was the most influential factor for referral, followed by an interaction of obstructive CAD with pre-test likelihood of CAD (P = 0.0344). Within CCTA CAD groups, rates of revascularization increased from 3.8% for non-high-risk CAD to 51.2% high-risk CAD. In multivariable models, when compared with medical therapy, revascularization was associated with a survival advantage for patients with high-risk CAD [hazards ratio (HR) 0.38, 95% confidence interval 0.18-0.83], with no difference in survival for patients with non-high-risk CAD (HR 3.24, 95% CI 0.76-13.89) (P-value for interaction = 0.03). CONCLUSION In an intermediate-term follow-up, coronary revascularization is associated with a survival benefit in patients with high-risk CAD by CCTA, with no apparent benefit of revascularization in patients with lesser forms of CAD.

Reproducibility of coronary artery plaque volume and composition quantification by 64-detector row coronary computed tomographic angiography: An intraobserver, interobserver, and interscan variability study

BACKGROUND Interscan variability of coronary arterial plaque volume and composition quantification with coronary computed tomographic angiography (CCTA), an important attribute when considering CCTA as a serial modality, has not been examined. OBJECTIVE We sought to systematically determine intraobserver- and interobserver-interscan reproducibility of these measures. METHODS Two blinded, experienced readers independently evaluated proximal coronary segments on CCTAs from 30 patients who underwent 2 scans within 200 days (median, 124 days; interquartile range, 49-155 days) without experiencing an interim acute coronary event. Readers recorded number of plaques and, in plaques that met a preset minimal length criterion, quantified total, calcified plaque (CP), and noncalcified plaque (NCP) volumes and percentage of total plaque volume occupied by NCP. RESULTS Of 89 total segments studied, 36 contained detectable plaque, and 26 met criterion for quantification. Intraobserver, interobserver, and interscan agreements for normal segments were 100%. Intraobserver-interscan correlations of total, CP, and NCP volumes and percentage of NCP were excellent (r=0.93-0.97, P values<0.001). Interobserver-interscan correlations for all measures were also very good (r=0.81-0.96, P values<0.001). Variability in plaque volume quantification was significant, exceeding 60% of the averaged paired plaque volumes in the best-case scenario (interobserver-interscan CP volume). Quantification of percentage of NCP composition by volume was more consistent, with <24% variation in the worst-case scenario (interobserver-interscan). CONCLUSION CCTA shows promise for quantifying serial coronary plaque change. Currently, the most robust measure seems to be percentage of plaque composition, rather than plaque volume. For smaller plaques, volume quantification remains challenging.

Contrast Medium–Induced Acute Kidney Injury: Comparison of Intravenous and Intraarterial Administration of Iodinated Contrast Medium

PURPOSE To compare the incidence of contrast medium-induced acute kidney injury (AKI) after intravenous (IV) administration of iodixanol for computed tomographic (CT) angiography versus intraarterial (IA) injection of iodixanol or low osmolar contrast medium (LOCM) for digital subtraction angiography (DSA) within the same population suspected of peripheral arterial occlusive disease (PAOD). MATERIALS AND METHODS CT angiography was performed with IV iodixanol 320 mgI/mL. After a washout period of 3-14 days, DSA was performed with IA iodixanol or LOCM. Serum creatinine was measured at baseline and 24 hours after administration. Contrast medium-induced AKI was defined by a serum creatinine increase of at least 25% versus baseline at 24 hours. Data were analyzed with χ(2) statistics. RESULTS Mean baseline serum creatinine values were comparable between CT angiography with IV contrast medium and DSA with IA contrast medium (93.3 μmol/L ± 52.92 vs 92.8 μmol/L ± 61.70). The incidence of AKI for CT angiography after IV iodixanol administration was 7.6% (20 of 264), which was not statistically different than the 8.7% incidence (22 of 253) for DSA with IA iodixanol or LOCM (P = .641). In the 143 patients who received only iodixanol for both procedures, incidences of contrast medium-induced AKI were comparable after IV (7.0%) and IA (5.6%) administration (P = .626). CONCLUSIONS The rates of contrast medium-induced AKI are not statistically different between IV iodixanol for CT angiography and IA iodixanol or another LOCM for DSA in the same population with suspected PAOD.

Subacute stent thrombosis associated with a heparin-coated stent and heparin-induced thrombocytopenia.

Subacute stent thrombosis occurred in a patient 34 days after receiving a heparin‐coated (HC) stent. The patient developed heparin‐induced thrombocytopenia and diffuse thrombosis after the stent was placed. This raises the concern that patients who develop heparin‐associated antibodies in the context of a recently placed HC stent may have an increased risk for subacute stent thrombosis. Cathet Cardiovasc Intervent 2003;58:80–83.