64-slice Computed Tomography Coronary Angiography Research Articles

Utility of 64-Slice Coronary Computed Tomography Angiography in Heart Transplant Recipients

Graft vasculopathy is a leading cause of death after heart transplantation (HTx). Diagnosing cardiac allograft vasculopathy (CAV) within this patient group poses significant challenges. This study aimed to evaluate the safety and efficacy of coronary computed tomographic angiography (CCTA) in patients after HTx. We enrolled 107 consecutive HTx recipients (26 women, mean age 50 ± 17 years); all were ≥3 years post-HTx with minimal or no evidence of CAV in a prior coronary angiography performed a minimum of 2 years before the current examination. The inclusion criteria comprised an estimated glomerular filtration rate (eGFR) of ≥30, absence of new heart failure symptoms, and no contraindications to iodine contrast or CT scans. All patients underwent a 64-slice CCTA. In cases of minimal or no changes, noninvasive follow-up examinations were conducted. Significant changes in CT prompted additional coronary angiography. Of the enrolled participants, 9 exhibited minimal changes; 98 displayed no changes in coronary angiography. The median time since transplant was 7 years, with IQR of 4 to 11.25 years. Significant changes were excluded in 98 patients. Among the 9 patients with suspected significant CAV, significant changes were confirmed in 8 patients, resulting in percutaneous transluminal coronary angioplasty (PTCA) performed in 6. One patient from this group died shortly after PTCA. No cardiovascular incidents were observed within the remaining group. The median follow-up period was 539 (IQR = 289-654 days). The mean left ventricular ejection fraction at follow-up was 58% ± 5% compared with 58% ± 4% at baseline. At follow-up, the mean eGFR was 64 ± 18 mL/kg/1.73 m2 compared with the baseline value of 67.2 mL/kg/1.73 m2. CCTA appears to offer a secure and efficient means of assessment in HTx recipients.

A Comparative Study of 64-Slice Coronary CT Angiography (CCTA) and Myocardial Perfusion Imaging (MPI) in the Identification of Coronary Artery Stenosis.

The aim of this study was to compare the diagnostic accuracy of 64-Slice Coronary Computer Tomography Angiography (CCTA) and Myocardial Perfusion Imaging (MPI) in the identification of significant coronary artery stenosis (>50% luminal narrowing). A total of 120 patients suspected of having coronary artery disease were divided into two groups, with 60 patients in each group. Group 1 underwent CCTA and group 2 underwent MPI. Diagnostic accuracy parameters, image quality, radiation exposure, and procedure time were compared. CCTA demonstrated higher sensitivity (90% vs. 80%, p = 0.049) and similar specificity (75% vs. 70%, p = 0.453) compared to MPI. Image quality was slightly superior in the CCTA group. Radiation exposure was significantly lower in the CCTA group compared to the MPI group (3.5 ± 1.2 mSv vs. 9.4 ± 1.7 mSv, p < 0.001). The procedure time for CCTA was also significantly less than that for MPI (10.3 ± 2.1 minutes vs. 45.2 ± 5.3 minutes, p < 0.001). CCTA showed superior sensitivity, image quality, and efficiency compared to MPI while exposing patients to a lower radiation dose. Further multicenter studies with larger patient populations are needed to validate these findings.

The relationship of platelet to lymphocyte ratio with the presence and extent of coronary atherosclerosis detected by coronary computed tomography angiography

Objectives: Platelet-lymphocyte ratio (PLR) combines the predictive risk of platelet and lymphocyte counts into a single risk index. PLR has been studied as a predictive marker in a variety of cardiovascular diseases. However, our understanding of the link between PLR and coronary artery disease (CAD) remains limited. The present study aimed to evaluate the relationship between PLR and intensity of coronary atherosclerosis in patients with suspected CAD. Methods: In this retrospective study, we included 221 patients undergoing dual-source 64-slice coronary computed tomography angiography (CCTA). Total and different types of leukocyte counts were measured with an automatic blood counter. Based on a modified version of the American Heart Association's categorisation, the coronary artery tree was divided into 16 segments. To assess the extent of coronary atherosclerosis, the number of affected coronary segments was counted. Coronary artery plaques were classified into three categories: (1) calcified plaque, (2) non-calcified plaque, and (3) mixed plaque. Results: After multivariable backward stepwise regression analysis, PLR remained as an independent predictor for both the presence and extent of coronary atherosclerosis (OR=2.38, 95% CI: 1.27-4.47 and OR=1.66, 95% CI: 1.10-2.51, respectively). There was no significant relationship between PLR and plaque morphology. Conclusions: Higher PLR was associated with the intensity of coronary atherosclerosis detected by CCTA. Further research is necessary to determine the optimal approach to using PLR in medical practice.

Comparison of Clinical Diagnostic Value of 64-Slice Spiral CT Coronary Angiography and Coronary Angiography in the Diagnosis of Coronary Artery Stenosis

Comparison of Clinical Diagnostic Value of 64-Slice Spiral CT Coronary Angiography and Coronary Angiography in the Diagnosis of Coronary Artery Stenosis

Abstract 13620: Comparison of Endothelial Shear Stress (ESS) Computation Utilizing Non-Invasive Coronary Computed Tomography Angiography (CCTA) vs Invasive Intravascular Ultrasound (IVUS) Imaging

Introduction: Risk-stratification of individual coronary plaques is an important goal to detect high-risk plaques likely to progress/destabilize, which could inform preemptive intervention to prevent adverse cardiac events. IVUS imaging, the current gold standard to assess plaque risk, has shown that biomechanical variables, particularly local ESS, contributes critical synergistic prognostic insight when combined with anatomic high-risk plaque features. Non-invasive risk assessment of coronary plaques with CCTA would be invaluable to enable broad population risk screening, but it is unknown whether CCTA, which has less spatial resolution than IVUS, can adequately measure the critical local biomechanical and anatomic variables. Aim: To compare the accuracy of ESS computation of local ESS metrics by non-invasive CCTA vs invasive IVUS imaging. Methods: We analyzed 30 arteries (22 LAD, 4 LCx,4 RCA) from 30 patients selected from a registry of patients who underwent both IVUS and CCTA of the same artery for suspected CAD. CCTA images were acquired using a CCTA with either 64 or 256 detector rows. We segmented lumen, vessel, and plaque areas with both IVUS (manual segmentation) and CCTA (AI based software; Cleerly Inc, NY). Co-registration of IVUS and CCTA Images was performed using fiduciary anatomic landmarks. Images from IVUS and CCTA were used to generate a 3-D arterial reconstruction, and local ESS distribution was assessed by computational fluid dynamics and reported in consecutive 3-mm segments. Results: Table Conclusion: Compared to IVUS values, 256-slice is more accurate than 64-slice CCTA to measure lumen and vessel areas, but computation of detailed local ESS (average, low and high) is similar by both CCTA methods. Local ESS evaluation using non-invasive CCTA is feasible and comparable to invasive gold standard IVUS and is suitable to characterize the local flow patterns that play an important role in plaque development, progression, and destabilization

Diagnostic accuracy of prospectively gated, 128-slice or greater CTCA at high heart rates: a systematic review and meta-analysis.

IntroductionProspectively gated 64‐slice CT coronary angiography (CTCA) may be contraindicated for heart rates (HRs) over 65 beats per minute (bpm) due to reduced diagnostic sensitivity. Newer CT scanners typically provide 128 or more slices and superior temporal resolution compared with older models; consequently, diagnostic accuracy for current technology prospectively gated CTCA may be adequate at HRs above 65 bpm. The aim of this systematic review was to investigate the diagnostic accuracy of CTCA using 128‐slice or greater CT technology when compared with conventional coronary angiography for patients with HRs >65 bpm.MethodsA systematic search of PubMed, CINAHL, EMBASE and Scopus was performed as well as unpublished databases, sources and reference lists. Titles and abstracts were screened by two independent reviewers. Full‐text screening was then performed. Studies that determined diagnostic accuracy of coronary artery stenosis in adult patients with high heart rates utilising prospectively gated 128 detector or greater scanners were included. Studies that were included in the review underwent critical appraisal using the QUADAS‐2 tool.ResultsTen studies were included in the systematic review, with nine of these included in a diagnostic test accuracy meta‐analysis, including six of which reported data at the patient level. Meta‐analysis indicated very high pooled sensitivity 100% (95% CI 0.99, 1.00); however, pooled specificity was less at 79% (95% CI 0.69, 0.88).ConclusionsProspectively gated CT coronary angiography may be justifiable at heart rates above 65 bpm if performed on a 128‐slice or greater CT unit. Caution regarding the implication of a positive result is recommended due to reduced specificity. Further evidence is required before consideration of a new higher heart threshold.

1268A comparison between the diagnostic performance of quantitative flow ratio and non-invasive imaging modalities for diagnosing myocardial ischemia defined by FFR, a PACIFIC-trial interim analysis

Abstract Background Quantitative flow ratio (QFR) uses fast computational algorithms based on 3-dimensional quantitative coronary angiography and estimation of contrast flow velocity during invasive coronary angiography (ICA) to obtain QFR values equivalent to fractional flow reserve (FFR). Objective To compare the diagnostic performance of QFR with coronary computed tomography angiography (CCTA), single-photon emission tomography (SPECT), and positron emission tomography (PET) for diagnosing myocardial ischemia defined by FFR. Method QFR computation was attempted in 109 patients (286 vessels without a subtotal/total lesion) of the 208 patients included in the PACIFIC-trial. Patients underwent 256-slice CCTA, Tetrofosmin SPECT, and [15O]H2O PET prior to ICA in conjunction with 3 vessel FFR measurements. ICA images were obtained without the use of a dedicated QFR acquistion protocol. QFR was calculated using a fixed empiric hyperemic flow velocity (fQFR) as well as using a patient specific flow velocity based on contrast passage through the coronary (cQFR). All analysis were performed on a per vessel level. Results Fixed QFR computation succeeded in 152 (53%) vessels while cQFR analysis was successful in 140 (49%) vessels. A good correlation between FFR and fQFR/cQFR was observed (R=0.774, p&lt;0.001/R=0.790, p&lt;0.001). The diagnostic performance in terms of sensitivity, specificity, negative predictive value, positive predictive value, and accuracy is presented in table 1. In total, 133 vessels with matched FFR, fQFR, cQFR, CCTA, SPECT, and PET results were available for the comparative C-statistic analysis, figure 1. The diagnostic performance of fQFR and cQFR was comparable (p=0.451) and superior to CCTA (p=0.004/p=0.003), SPECT (p&lt;0.001/p&lt;0.001), and PET (p=0.008/p=0.006), figure 1. CCTA, and PET performed alike (p=0.568) and outperformed SPECT (p=0.023, p=0.002). Table 1 % (95% Confidence Interval) fQFR n=152 cQFR (n=140) CCTA (n=152) SPECT (n=150) PET (n=149) Sensitivity 76 (59–89) 71 (53–86) 70 (51–84) 30 (16–49) 76 (58–89) Specificity 94 (88–98) 93 (86–97) 73 (64–81) 96 (90–99) 80 (72–87) Negative Predictive Value 93 (88–96) 92 (86–95) 90 (84–94) 83 (79–86) 92 (86–96) Positive Predictive Value 79 (64–89) 74 (59–85) 42 (33–51) 67 (42–84) 52 (42–62) Accuracy 90 (84–94) 88 (81–93) 72 (65–79) 81 (74–87) 79 (72–85) Figure 1. Conclusion Fixed QFR and cQFR correlate well with FFR with a high diagnostic accuracy as result. QFR outperformed CCTA, SPECT, and PET for the diagnosis of myocardial ischemia on a per vessel basis with the important footnote that fQFR and cQFR could only be computed in 53%, and 49% of the vessels.

Adverse Plaque Characteristics Relate More Strongly With Hyperemic Fractional Flow Reserve and Instantaneous Wave-Free Ratio Than With Resting Instantaneous Wave-Free Ratio

ObjectivesThe current substudy of the PACIFIC (Prospective Comparison of Cardiac PET/CT, SPECT/CT Perfusion Imaging and CT Coronary Angiography With Invasive Coronary Angiography) trial explores the impact of computed tomography (CT)–derived unfavorable plaque features on both hyperemic and non-hyperemic flow indices. BackgroundNext to lesion severity, plaque vulnerability as assessed using coronary CT angiography affects fractional flow reserve (FFR), which is associated with imminent acute coronary syndromes. Instantaneous wave-free ratio (iFR) has recently emerged as an alternative for FFR to interrogate coronary lesions for ischemia. It is, however, unknown whether vasodilator-free assessment with iFR is associated with plaque stability similarly as FFR. MethodsOf 120 patients (62% men, age 58.3 ± 8.6 years) with suspected coronary artery disease, 257 vessels were prospectively evaluated. Each patient underwent 256-slice coronary CT angiography to assess stenosis severity and plaque features (positive remodeling [PR], low attenuation plaque [LAP], spotty calcification [SC], and napkin ring sign [NRS]), as well as intracoronary pressure measurements (FFR, iFR, Pd/Pa, and pressure ratio during adenosine within the wave-free period [iFRa]). CT-derived plaque characteristics were related to these invasive pressure measurements. ResultsAtherosclerotic plaques were present in 170 (66%) coronary arteries. On a per-vessel basis, luminal stenosis severity was significantly associated with impaired FFR, iFR, Pd/Pa, and iFRa. Multivariable analysis revealed that FFR and iFR were independently related to ≥70% stenosis (−0.10, p < 0.001 and −0.09, p = 0.003, respectively) and plaque volume (-0.02, p = 0.020 and -0.02, p = 0.030, respectively). Additionally, PR and SC were also independent predictors of an impaired FFR (−0.10, p < 0.001 and −0.07, p = 0.021, respectively), but adverse plaque characteristics were not independently related to the vasodilator-free iFR. ConclusionsCT-derived vulnerable plaque characteristics are independently associated with hyperemic flow indices as assessed with FFR and iFRa, but not with non-hyperemic indices such as iFR and Pd/Pa. These findings suggest that the effects of hyperemia on pressure-derived indices might depend not only on hemodynamic stenosis severity but also on plaque characteristics.

Comprehensive coronary plaque assessment in patients with obstructive sleep apnea.

Obstructive sleep apnea (OSA) is associated with an increased risk of cardiovascular disease. Previous studies have assessed the relationship between OSA and coronary artery disease (CAD) using coronary artery calcium score (CAC) measurements. However, limited data are available regarding the association of OSA with non-calcified plaque burden. We therefore aimed to assess the relationship between CAD severity as assessed by coronary computed tomography angiography (CTA) and OSA. Forty-one adult subjects (59±9years, 15 men) underwent a 256-slice coronary CTA, which was followed by a diagnostic attended cardiorespiratory polygraphy (n=13) or polysomnography (n=28). Segment involvement score (SIS), segment stenosis score (SSS) and CAC were used to quantify total CAD burden. Correlation analysis was used to assess potential associations between CAD and OSA. Twenty-two patients were diagnosed with OSA. SIS and SSS were elevated in OSA (2.90±2.78 versus 1.79±2.39 and 4.91±5.94 versus 1.79±4.54, OSA versus controls, SIS and SSS respectively, both p<0.01) and correlated with OSA severity as measured by the apnea-hypopnea index (AHI, r=0.41 and 0.43, p<0.01) and oxygen desaturation index (ODI, r=0.45 and 0.46, p<0.01). However, no significant correlation was observed between CAC and OSA. Compared to CAC, SIS and SSS provide additional information on coronary plaque burden in OSA, which shows a significant association with OSA.

Comparison of Coronary Computed Tomography Angiography, Fractional Flow Reserve, and Perfusion Imaging for Ischemia Diagnosis

BackgroundFractional flow reserve (FFR) computation from coronary computed tomography angiography (CTA) datasets (FFRCT) has emerged as a promising noninvasive test to assess hemodynamic severity of coronary artery disease (CAD), but has not yet been compared with traditional functional imaging. ObjectivesThe purpose of this study was to evaluate the diagnostic performance of FFRCT and compare it with coronary CTA, single-photon emission computed tomography (SPECT), and positron emission tomography (PET) for ischemia diagnosis. MethodsThis subanalysis involved 208 prospectively included patients with suspected stable CAD, who underwent 256-slice coronary CTA, 99mTc-tetrofosmin SPECT, [15O]H2O PET, and routine 3-vessel invasive FFR measurements. FFRCT values were retrospectively derived from the coronary CTA images. Images from each modality were interpreted by core laboratories, and their diagnostic performances were compared using invasively measured FFR ≤0.80 as the reference standard. ResultsIn total, 505 of 612 (83%) vessels could be evaluated with FFRCT. FFRCT showed a diagnostic accuracy, sensitivity, and specificity of 87%, 90%, and 86% on a per-vessel basis and 78%, 96%, and 63% on a per-patient basis, respectively. Area under the receiver-operating characteristic curve (AUC) for identification of ischemia-causing lesions was significantly greater for FFRCT (0.94 and 0.92) in comparison with coronary CTA (0.83 and 0.81; p < 0.01 for both) and SPECT (0.70 and 0.75; p < 0.01 for both), on a per-vessel and -patient level, respectively. FFRCT also outperformed PET on a per-vessel basis (AUC 0.87; p < 0.01), but not on a per-patient basis (AUC 0.91; p = 0.56). In the intention-to-diagnose analysis, PET showed the highest per-patient and -vessel AUC followed by FFRCT (0.86 vs. 0.83; p = 0.157; and 0.90 vs. 0.79; p = 0.005, respectively). ConclusionsIn this study, FFRCT showed higher diagnostic performance than standard coronary CTA, SPECT, and PET for vessel-specific ischemia, provided coronary CTA images were evaluable by FFRCT, whereas PET had a favorable performance in per-patient and intention-to-diagnose analysis. Still, in patients in whom 3-vessel FFRCT could be analyzed, FFRCT holds clinical potential to provide anatomic and hemodynamic significance of coronary lesions.

The evaluation of coronary artery-to-pulmonary artery fistula in adulthood on 256-slice CT coronary angiography: Comparison with coronary catheter angiography and transthoracic echocardiography

ObjectiveTo review the imaging features of coronary artery-to-pulmonary artery fistula (CPAF) on CT coronary angiography (CTCA) and evaluate its diagnostic performance compared with coronary catheter angiography (CCA) and transthoracic echocardiography (TTE). Materials and methodsWe retrospectively reviewed with a diagnosis of CPAF from among 19855 consecutive CCTA performed with 256-slice MDCT scanner for suspected coronary artery disease. CT images were evaluated for – origin, number, size and course (tubular/worm-like dilation/significant aneurysm formation/wall attachment sign) of fistula vessels, drainage site, drainage site imaging features (pierced sign, isodensity sign, smoke sign, jet sign), and main pulmonary artery (MPA) enlargement. 25 patients of CPAF also underwent CCA and 47 patients underwent TTE. ResultsThere were 72 patients with CPAF (0.36%) in our study, of which 44 were men and 28 were women, with mean age of 55.8 ± 13.2 years (range 22–85 years). CPAF originated from conus artery, left anterior descending artery (LAD), combined conus artery and LAD in 55, 67, 50 cases, respectively. Tubular dilation, worm-like dilation and aneurysm was seen in 14, 58 and 35 cases, respectively. Wall attachment sign was noted in 69 cases. All the cases demonstrated only a single drainage site, with left lateral wall, left anterolateral, anterior, right lateral and right anterolateral walls of MPA in 44, 21, 5, 1 and 1 cases, respectively. The mean diameter of the fistula drainage site was 2.6 ± 1.3 mm. Pierced sign, jet sign, smoke sign, isodensity sign was seen in 72, 46, 41 and 24 cases, respectively. MPA enlargement was seen in 20 patients. CCA showed CPAF in only 20 cases among 25 patients; while TTE showed CPAF in only 9 patients among 47 patients. ConclusionCTCA is competent in detecting and characterizing CPAF with an excellent diagnostic performance as the first imaging modality of choice, which is valuable for giving a distinct and intuitive explanation to patients and physicians and making an objective and exact assessment for further management.

Coronary computed tomography angiography (CCTA) quality

Coronary computed tomography angiography (CCTA) is increasingly being utilized for assessment of coronary artery disease. New techniques for CCTA intend to reduce the radiation dose, whereas maintaining the image quality. This research was carried out in order to explore the advantages of assessing the image quality of the non-enhanced CT scan in the pre-determination of the best CCTA gating protocol, which we hypothesized to result in better image quality and lower radiation exposure. A prospective analysis of the 150 non-enhanced CT scans which were performed before 256-slice CCTA to look into the presence of artifacts affecting the coronary arteries, the scan protocol (prospective vs. Prospective with padding or retrospective gating) was selected in the light of these observations. The image quality (four-point scale) and the radiation dose were compared with 150 standard CCTA scans performed without pre-selection of the desired protocol. The median age of the patients was 49 (23–78) years and the average heart rate during the CCTA scan was 62 ± 14 beats per minute. We found that the subjective image quality obtained with the guidance of the pre-selection of the scan protocol is better compared to the standard CCTA scanning, especially when the heart rate is more than 65 per minute (3.5 ± 0.5 vs. 2.8 ± 0.8; p = 0.06) respectively. The overall radiation dose was significantly lower in the pre-selection group compared to the standard CCTA (4.9 ± 1.4 vs. 7.5 ± 1.8 mSv; p <;0.01) respectively, The use of Prospective with padding or retrospective gating was infrequent in the non-enhanced scans based pre-selection of CCTA protocol compared to the standard group (14 out of 150 versus 28 out of 150 scans) respectively. The use of 256-raw CCTA and the determination of the acquisition protocol based on the assessment of the non-enhanced CT scan, prompts better image quality and a significant radiation exposure reduction. We recommend performing this analysis to guide the selection of the CCTA scan protocol.

Plaque Morphology as Predictor of Late Plaque Events in Patients With Asymptomatic Type 2 Diabetes: A Long-Term Observational Study

ObjectivesThe authors used coronary computed tomography angiography (CTA) to determine plaque characteristics predicting individual late plaque events precipitating acute coronary syndromes (ACS) in a cohort of asymptomatic type 2 diabetic patients. BackgroundIn patients with coronary artery disease, CTA plaque characteristics may predict mid-term patient events. MethodsAsymptomatic patients with diabetes 55 to 74 years of age with no history of coronary artery disease (N = 630) underwent baseline 64-slice CTA and detailed plaque level analysis. All subsequent clinical events were recorded and adjudicated. In patients who developed ACS, culprit plaque was identified at invasive angiography and its precursor located on the baseline CTA. Plaque characteristics predicting an ACS-associated culprit plaque event were analyzed by time to event accounting for inpatient clustering of plaques and competing events. ResultsAmong 2,242 plaques in 499 subjects, 24 ACS culprit plaques were identified in 24 subjects during median follow-up of 9.2 years (interquartile range: 8.4 to 9.8 years). Plaque volume (upper vs. lower quartile hazard ratio [HR]: 6.9; 95% confidence interval [CI]: 1.6 to 30.8; p = 0.011), percentage of low-density plaque content <50 Hounsfield units (HR: 14.2; 95% CI: 1.9 to 108; p = 0.010), and mild plaque calcification (HR vs. all other plaques 3.3 [95% CI: 1.5 to 7.3]; p = 0.004) predicted plaque events univariately and after adjustment by clinical risk score. A culprit plaque event occurred in 13 of 376 (3.5%) high-risk plaques (HRP) (plaques with ≥2 risk predictors) versus 11 of 1,866 (0.6%) in non-HRPs (p < 0.0001), at 12 of 343 (3.5%) stenotic sites (≥50%) versus 12 of 1,899 (0.6%) nonstenotic sites (p < 0.0001) and in 7 of 131 (5.3%) HRP with stenosis (p < 0.0001 vs. all others). In 130 (20.6%) subjects, no coronary plaque was present on baseline CTA. ConclusionsIn asymptomatic patients with type 2 diabetes, CTA plaque volume, percent low-density plaque content, and mild calcification predicted late plaque events. The additional presence of luminal stenosis increased the probability of an acute event.

High-sensitivity cardiac troponin I is a biomarker for occult coronary plaque burden and cardiovascular events in patients with rheumatoid arthritis.

Patients with RA display greater occult coronary atherosclerosis burden and experience higher cardiovascular morbidity and mortality compared with controls. We here explored whether pro-inflammatory cytokines and high-sensitivity cardiac troponin I (hs-cTnI), a biomarker of myocardial injury, correlated with plaque burden and cardiovascular events (CVEs) in RA. We evaluated 150 patients with 64-slice coronary CT angiography. Coronary artery calcium, number of segments with plaque (segment involvement score), stenotic severity and plaque burden were assessed. Lesions were described as non-calcified, mixed or fully calcified. Blood levels of hs-cTnI and pro-inflammatory cytokines were assessed during coronary CT angiography. Subjects were followed over 60 (s.d. 26) months for both ischaemic [cardiac death, non-fatal myocardial infarction (MI), stroke, peripheral arterial ischaemia] and non-ischaemic (new-onset heart failure hospitalization) CVEs. Plasma hs-cTnI correlated with all coronary plaque outcomes (P < 0.01). Elevated hs-cTnI (⩾1.5 pg/ml) further associated with significant calcification, extensive atherosclerosis, obstructive plaque and any advanced mixed or calcified plaques after adjustments for cardiac risk factors or Framingham D'Agostino scores (all P < 0.05). Eleven patients suffered a CVE (1.54/100 patient-years), eight ischaemic and three non-ischaemic. Elevated hs-cTnI predicted all CVE risk independent of demographics, cardiac risk factors and prednisone use (P = 0.03). Conversely, low hs-cTnI presaged a lower risk for both extensive atherosclerosis (P < 0.05) and incident CVEs (P = 0.037). Plasma hs-cTnI independently associated with occult coronary plaque burden, composition and long-term incident CVEs in patients with RA. Low hs-cTnI forecasted a lower risk for both extensive atherosclerosis as well as CVEs. hs-cTnI may therefore optimize cardiovascular risk stratification in RA.

FRACTIONAL FLOW RESERVE BUT NOT INSTANTANEOUS WAVE-FREE RATIO DETECTS PLAQUE VULNERABILITY

Background: Fractional fow reserve (FFR) is, next to lesion severity, affected by plaque vulnerability as assessed by coronary computed tomography angiography (CCTA) and associated with imminent acute coronary syndromes. Instantaneous wave-free ratio (iFR) has recently emerged as an alternative for FFR to interrogate coronary lesions for ischemia. It is, however, unknown whether vasodilator free assessment with iFR is associated with plaque stability similarly as FFR. The current substudy of the PACIFIC trial explores the impact of CCTA derived unfavorable plaque features on both hyperemic and non-hyperemic fow indices in order to detect vulnerable plaques. Methods: Of 119 patients (62% men, age 58 ± 8.6 years) with suspected coronary artery disease, 257 vessels were prospectively evaluated. Each patient underwent 256-slice CCTA to assess stenosis severity and plaque features (positive remodeling (PR), low attenuation plaque (LAP), spotty calcifcation (SC) and napkin ring sign (NRS)), as well as intracoronary pressure measurements (FFR, iFR, resting Pd/Pa and pressure ratio during adenosine within the wave-free period (iFRa)). CCTA derived plaque characteristics were related to these invasive pressure measurements. Results: Atherosclerotic plaques were present in 170 (66%) coronary arteries. On a per-vessel basis, luminal stenosis severity was signifcantly associated with impaired FFR, iFR, resting Pd/Pa and iFRa. Multivariable analysis revealed that PR and LAP were independently related to an impaired FFR (p = 0.006 and p = 0.038, respectively) and iFRa (p = 0.005 and p = 0.027, respectively), next to stenosis severity (p <0.001 for all). Conversely, these adverse plaque characteristics were not related to the vasodilator free parameters iFR and Pd/Pa. Conclusion: CCTA derived vulnerable plaque characteristics are associated with detrimental hyperemic fow indices as assessed with FFR and iFRa, but not with non-hyperemic indices as defined by iFR and resting Pd/Pa. These findings suggest that induction of hyperemia is mandatory to reveal plaque vulnerability during hemodynamic interrogation of a coronary artery.

Higher Coronary Plaque Burden in Psoriatic Arthritis Is Independent of Metabolic Syndrome and Associated With Underlying Disease Severity.

To examine the effect of metabolic syndrome and psoriatic disease-related variables on coronary plaque burden in psoriatic arthritis (PsA) patients. Fifty PsA patients without symptoms of coronary artery disease (CAD) (25 with metabolic syndrome and 25 without metabolic syndrome) and 50 age- and sex-matched controls underwent 64-slice coronary computed tomography angiography. Plaque localization, segment involvement score (SIS), segment stenosis score (SSS), and total plaque volume (TPV) were calculated. Plaques were classified as calcified, mixed, or noncalcified. Kruskal-Wallis test, rank correlations, and linear regression analyses were used to study the relationship between PsA, metabolic syndrome, and plaque burden. Plaques were found in 76% of PsA patients versus 44% of controls (P = 0.001), and a higher proportion of patients with PsA had affected coronary vessels (P = 0.007). SIS, SSS, and TPV were greater in PsA patients than controls (P = 0.003, P = 0.001, and P ≤ 0.001, respectively). More PsA patients had mixed plaques, and mixed plaque volume was higher than in controls (P < 0.001). PsA patients with metabolic syndrome and those without metabolic syndrome had similar plaque burdens and types. SIS, SSS, and TPV did not show significant relationships with features of metabolic syndrome, but did significantly correlate with disease activity measures. TPV was associated with a diagnosis of PsA (B = 0.865, P = 0.008), but not with metabolic syndrome. Age, highest C-reactive protein level, highest swollen joint count, disease duration, and plasma glucose level were independent predictors of higher plaque burden in PsA. PsA is associated with accelerated coronary plaque formation, particularly mixed plaques, independent of metabolic disease. Psoriatic disease activity and severity may predict coronary plaque burden better than traditional risk factors.

Effect of Plaque Burden and Morphology on Myocardial Blood Flow and Fractional Flow Reserve

BackgroundAtherosclerotic plaque characteristics may affect downstream myocardial perfusion, as well as coronary lesion severity. ObjectivesThis study sought to evaluate the association between quantitative plaque burden and plaque morphology obtained using coronary computed tomography angiography (CTA) and quantitative myocardial perfusion obtained using [15O]H2O positron emission tomography (PET), as well as fractional flow reserve (FFR) derived invasively. MethodsTwo hundred eight patients (63% men; age 58 ± 8.7 years) with suspected coronary artery disease were prospectively included. All patients underwent 256-slice coronary CTA, [15O]H2O PET, and invasive FFR measurements. Coronary CTA-derived plaque burden and morphology were assessed using commercially available software and compared with PET perfusion and FFR. ResultsAtherosclerotic plaques were present in 179 patients (86%) and 415 of 610 (68%) evaluable coronary arteries. On a per-vessel basis, traditional coronary plaque burden indexes, such as plaque length and volume, minimal lumen area, and stenosis percentage, were significantly associated with impaired hyperemic myocardial blood flow (MBF) and FFR. In addition, morphological features, such as partially calcified plaques, positive remodeling (PR), and low attenuation plaque, displayed a negative impact on hyperemic MBF and FFR. Multivariable analysis revealed that the morphological feature of PR was independently related to impaired hyperemic MBF as well as an unfavorable FFR (p = 0.004 and p = 0.007, respectively), next to stenosis percentage (p = 0.001 and p < 0.001, respectively) and noncalcified plaque volume (p < 0.001 and p = 0.010, respectively). ConclusionsPR and noncalcified plaque volume are associated with detrimental downstream hyperemic myocardial perfusion and FFR, independent of lesion severity.

Assessment of Effective Dose Associated with Coronary Computed Tomography Angiography in Isfahan Province, Iran

Computed tomography coronary angiography (CTCA) has generated a great interest over the past two decades, due to its high diagnostic accuracy and efficacy in the assessment of patients having coronary artery disease. This method is associated with high radiation dose and this has raised serious concerns in the literature. Effective dose (E) is a single parameter meant to reflect the relative risk from exposure to ionizing radiation. Therefore, it is necessary to calculate this parameter to indicate ionizing radiation relative risk. The aim of this study was to calculate the effective dose from 64-slice CTCA in Isfahan. To calculate the effective dose, an ionization chamber and a body phantom with diameter of 32 cm and length of 15 cm were used. CTCA radiation conditions commonly used in two centers were applied for this work. For all scans, computed tomography volume dose index (CTDIv), dose-length product (DLP), and effective dose were obtained using dose-length-product method. The obtained CTDIv, DLP, and effective dose were compared in two centers, and mean, maximum, and minimum values of effective dose for heart coronary CT angiography (CCTA) examinations and calcium score were compared with other studies. The amount of average, maximum, and minimum effective doses for heart CCTA examinations in two centers are 4.65 ± 0.06, 6.0489, and 3.492 mSv, respectively, and for calcium score test are, 1.04 ± 0.04, 2.155, and 0.98 mSv, respectively. CTDIv, DLP, and effective dose values did not show any significant difference in two centers. Although the effective dose of CTCA and calcium score was lower than that of other studies, it is reasonable to reduce the effective dose to the minimum possible value to reduce the risk of cancer associated with ionizing radiation. The results of this study can be used to introduce the effective dose as a local diagnostic reference dose (DRL) for CTCA examinations in Isfahan Province.

Long-term prognostic performance of low-dose coronary computed tomography angiography with prospective electrocardiogram triggering.

To assess long-term prognosis after low-dose 64-slice coronary computed tomography angiography (CCTA) using prospective electrocardiogram-triggering. We included434 consecutive patients with suspected or known coronary artery disease referred for low-dose CCTA. Patients were classified as normal, with non-obstructive or obstructive lesions, or previously revascularized. Coronary artery calcium score (CACS) was assessed in 223 patients. Follow-up was obtained regarding major adverse cardiac events (MACE): cardiac death, myocardial infarction and elective revascularization. We performed Kaplan-Meier analysis and Cox regressions. Mean effective radiation dose was 1.7 ± 0.6mSv. At baseline, 38% of patients had normal arteries, 21% non-obstructive lesions, 32% obstructive stenosis and 8% were revascularized. Twenty-nine patients (7%)were lost to follow-up. After a median follow-up of 6.1 ± 0.6years, MACE occurred in 0% of patients with normal arteries, 6% with non-obstructive lesions, 30% with obstructive stenosis and 39% of those revascularized. MACE occurrence increased with increasingCACS (P < 0.001), but 4% of patients with CACS = 0 experienced MACE. Multivariate Cox regression identified obstructive stenosis, lesion burden in CCTA and CACS as independent MACE predictors (P ≤ 0.001). Low-dose CCTA with prospective electrocardiogram-triggering has an excellent long-term prognostic performance with a warranty period >6years for patients with normal coronary arteries. • Coronary CT angiography (CCTA) has an excellent long-term prognostic performance. • CCTA can accurately stratify cardiac risk according to coronary lesion severity. • A normal CCTA predicts freedom from cardiac events for >6years. • Patients with a coronary calcium score of 0 may experience cardiac events. • CCTA allows for reclassification of cardiac risk compared with ESC SCORE.

Impact of Myocardial Bridge-mural Coronary Artery on Myocardial Blood Supply.

Objective To explore the impact of myocardial bridge-mural coronary artery (MB-MCA) on myocardial blood supply. Methods The imaging data of 74 patients with the isolate MB in the left anterior descending artery undergoing 256-slice CT coronary angiography and myocardial perfusion imaging (MPI) were retrospectively analyzed. The subjects were divided into incomplete and complete MB types. The length of MB and the systolic stenosis degree of MCA were measured.The type and length of MB and the systolic stenosis degree of MCA (according to Noble grade) were compared between the normal and abnormal MPI groups. The clinical characteristics including age, gender, body mass index, hypertension, dyslipidemia, diabetes mellitus, and smoking history were also reviewed. Results There were 38 incomplete MB cases and 13 complete MB cases in the normal MPI group,and 5 and 18 in the abnormal MPI group (χ2=18.134,P=0.000). The MB length in the normal and abnormal MPI group were (14.7±3.7) mm and (15.5±4.5) mm (t=0.804,P=0.424). However, the systolic stenosis degree of MCA showed significant difference (χ2=17.839,P=0.000). The clinical characteristics were not significantly differentt between the normal and abnormal MPI groups (P>0.05). Conclusions The MB type and the systolic stenosis degree of MCA can affect myocardial perfusion.Patients with complete MB and the moderate-to-severe systolic stenosis degree of MCA are more susceptible to myocardial ischemia. However, the MB length is not correlated with myocardial ischemia.