Impact of diabetes on coronary artery plaque volume by coronary CT angiography and subsequent adverse cardiac events

BackgroundTo investigate the impact of diabetes on coronary artery total plaque volume (TPV) and adverse events in long-term follow-up.MethodsOne-hundred-and-eight diabetic patients were matched to 324 non-diabetic patients, with respect to age, sex, body-mass index, hypertension, smoking habits, LDL and HDL cholesterol, family history for CAD as well as aspirin and statin medication. In all patients, TPV was quantified from coronary CT angiographies (CTA) using dedicated software. All-cause mortality, acute coronary syndrome and late revascularisation (>90 days) served as combined endpoint.ResultsPatients were followed for 5.6 years. The endpoint occurred in 18 (16.7%) diabetic and 26 (8.0%) non-diabetic patients (odds ratio 2.3, p = 0.03). Diabetic patients had significantly higher TPV than non-diabetic patients (55.1 mm³ [IQR: 6.2 and 220.4 mm³] vs. 24.9 mm³ [IQR: 0 and 166.7 mm³], p = 0.02). A TPV threshold of 110.5 mm³ provided good separation of diabetic and non-diabetic patients at higher and lower risk for adverse events. Noteworthy, diabetic and non-diabetic patients with a TPV<110.5 mm³ had comparable outcome (hazard ratio: 1.3, p = 0.59), while diabetic patients with TPV>110.5 mm³ had significantly higher incidence of adverse events (hazard ratio 2.3, p = 0.03) compared to non-diabetic patients with TPV>110.5 mm³. There was incremental prognostic value in diabetic and non-diabetic patients over the Framingham Risk Score (Integrated Discrimination Improvement: 0.052 and 0.012, p for both <0.05).ConclusionDiabetes is associated with significantly higher TPV, which is independent of other CAD risk factors. Quantification of TPV improves the identification of diabetic patients at higher risk for future adverse events.     

CT multivessel aggregate stenosis score: A novel point-of-care tool for predicting major adverse cardiac events

BackgroundWe evaluated the utility of a novel 15-point multivessel aggregate stenosis (MVAS) score for predicting major adverse cardiac events (MACE) in low-risk patients with suspected ischaemic symptoms undergoing CTCA. Prognostic performance was compared with the Coronary Artery Disease Reporting and Data System (CAD-RADS) classification and the 16-point Segment Involvement Score (SIS).Methods772 consecutive patients underwent CTCA and coronary artery calcification scoring (CACS) from 2010 to 2015. Coronary artery disease severity was calculated according to CAD-RADS class (0–5 ?± ?vulnerability modifier), the SIS (0–16), and an MVAS score (0–15) based on the aggregate stenosis severity in all 4 coronary vessels (maximum 12 points) plus the presence of any high-risk plaque features (additional 3 points). 52 patients were referred directly for coronary angiography based on CTCA findings and were excluded; the remainder were followed-up for 64.6 ?± ?19.1 months.Results54 ?MACE were observed in 720 patients (7.5%); MACE patients had higher CAD-RADS class (3.92 ?± ?0.7 vs 0.91 ?± ?1.2, p ?< ?0.0001), SIS (4.59 ?± ?2.7 vs 0.79 ?± ?1.2, p ?< ?0.0001), and MVAS scores (10.1 ?± ?1.7 vs 1.7 ?± ?2.1, p ?< ?0.0001). Adjusted Cox proportional hazards analysis identified CAD-RADS class (HR 2.96 (2.2–4), p ?< ?0.0001), SIS (HR 1.29 (1.2–1.4, p ?< ?0.0001), and MVAS score (HR 1.82 (1.6–2.1), p ?< ?0.0001) as predictors of MACE. Adjusted receiver operating characteristic (ROC) analysis found MVAS a more powerful predictor of MACE than CAD-RADS and SIS (AUC: 0.92 vs 0.84 vs 0.83, p ?= ?0.018).ConclusionsCAD-RADS and SIS are reliable predictors of MACE, and the MVAS score provided incremental prognostic data. MVAS may potentiate risk stratification, particularly in institutions without advanced plaque analysis software.     

Repeatability of quantitative pericoronary adipose tissue attenuation and coronary plaque burden from coronary CT angiography

BackgroundHigh pericoronary adipose tissue (PCAT) attenuation and non-calcified plaque burden (NCP) measured from coronary CT angiography (CTA) have been implicated in future cardiac events. We aimed to evaluate the interobserver and intraobserver repeatability of PCAT attenuation and NCP burden measurement from CTA, in a sub-study of the prospective SCOT-HEART trial.MethodsFifty consecutive CTAs from participants of the CT arm of the prospective SCOT-HEART trial were included. Two experienced observers independently measured PCAT attenuation and plaque characteristics throughout the whole coronary tree from CTA using semi-automatic quantitative software.ResultsWe analyzed proximal segments in 157 vessels. Intraobserver mean differences in PCAT attenuation and NCP plaque burden were ?0.05HU and 0.92% with limits of agreement (LOA) of ±1.54 and ± 5.97%. Intraobserver intraclass correlation coefficients (ICC) for PCAT attenuation and NCP burden were excellent (0.999 and 0.978). Interobserver mean differences in PCAT attenuation and NCP plaque burden were 0.13HU [LOA ±1.67HU] and ?0.23% (LOA ±9.61%). Interobserver ICC values for PCAT attenuation and NCP burden were excellent (0.998 and 0.944).ConclusionPCAT attenuation and NCP burden on CTA has high intraobserver and interobserver repeatability, suggesting they represent a repeatable and robust method of quantifying cardiovascular risk.     

Prognostic value of CT myocardial perfusion imaging and CT-derived fractional flow reserve for major adverse cardiac events in patients with coronary artery disease

ObjectivesThe purpose of this study was to analyze the prognostic value of dynamic CT perfusion imaging (CTP) and CT derived fractional flow reserve (CT-FFR) for major adverse cardiac events (MACE).Methods81 patients from 4 institutions underwent coronary computed tomography angiography (CCTA) with dynamic CTP imaging and CT-FFR analysis. Patients were followed-up at 6, 12, and 18 months after imaging. MACE were defined as cardiac death, nonfatal myocardial infarction, unstable angina requiring hospitalization, or revascularization. CT-FFR was computed for each major coronary artery using an artificial intelligence-based application. CTP studies were analyzed per vessel territory using an index myocardial blood flow, the ratio between territory and global MBF. The prognostic value of CCTA, CT-FFR, and CTP was investigated with a univariate and multivariate Cox proportional hazards regression model.Results243 vessels in 81 patients were interrogated by CCTA with CT-FFR and 243 vessel territories (1296 segments) were evaluated with dynamic CTP imaging. Of the 81 patients, 25 (31%) experienced MACE during follow-up. In univariate analysis, a positive index-MBF resulted in the largest risk for MACE (HR 11.4) compared to CCTA (HR 2.6) and CT-FFR (HR 4.6). In multivariate analysis, including clinical factors, CCTA, CT-FFR, and index-MBF, only index-MBF significantly contributed to the risk of MACE (HR 10.1), unlike CCTA (HR 1.2) and CT-FFR (HR 2.2).ConclusionOur study provides initial evidence that dynamic CTP alone has the highest prognostic value for MACE compared to CCTA and CT-FFR individually or a combination of the three, independent of clinical risk factors.     

Prognostic value of coronary computed tomography angiography in patients with prior percutaneous coronary intervention

ObjectiveWe sought to determine the prognostic value of coronary computed tomography angiography (CCTA) in patients with a history of percutaneous coronary intervention (PCI).BackgroundAlthough the prognostic value of CCTA has been well studied, its incremental value in patients with previous PCI has not been robustly investigated.MethodsConsecutive patients with previous PCI were prospectively enrolled and CCTA images were evaluated for coronary artery disease (CAD) severity. Patients were followed for major adverse cardiovascular events (MACE) which was a composite of cardiac death and non-fatal myocardial infarction. All-cause death was assessed as a secondary endpoint.ResultsA total of 501 patients were analyzed with a mean follow-up time of 59.5 ± 32.0 months and 52 patients (10.4%) experienced MACE. Multivariable Cox regression analysis showed that CAD severity was a predictor of MACE with 0, 1, 2, and 3 vessel disease having annual rates of 1.3%, 2.2%, 2.2%, and 5.3%, respectively. All-cause death was similar in all categories of CAD.ConclusionsIn patients with previous PCI, CAD severity as measured with CCTA has independent and incremental prognostic value.     

Progression of whole-heart Atherosclerosis by coronary CT and major adverse cardiovascular events

BackgroundThe current study aimed to examine the independent prognostic value of whole-heart atherosclerosis progression by serial coronary computed tomography angiography (CCTA) for major adverse cardiovascular events (MACE).MethodsThe multi-center PARADIGM study includes patients undergoing serial CCTA for symptomatic reasons, ≥2 years apart. Whole-heart atherosclerosis was characterized on a segmental level, with co-registration of baseline and follow-up CCTA, and summed to per-patient level. The independent prognostic significance of atherosclerosis progression for MACE (non-fatal myocardial infarction [MI], death, unplanned coronary revascularization) was examined. Patients experiencing interval MACE were not omitted.ResultsThe study population comprised 1166 patients (age 60.5 ?± ?9.5 years, 54.7% male) who experienced 139 MACE events during 8.2 (IQR 6.2, 9.5) years of follow up (15 death, 5 non-fatal MI, 119 unplanned revascularizations). Whole-heart percent atheroma volume (PAV) increased from 2.32% at baseline to 4.04% at follow-up. Adjusted for baseline PAV, the annualized increase in PAV was independently associated with MACE: OR 1.23 (95% CI 1.08, 1.39) per 1 standard deviation increase, which was consistent in multiple subpopulations. When categorized by composition, only non-calcified plaque progression associated independently with MACE, while calcified plaque did not. Restricting to patients without events before follow-up CCTA, those with future MACE showed an annualized increase in PAV of 0.93% (IQR 0.34, 1.96) vs 0.32% (IQR 0.02, 0.90), P ?< ?0.001.ConclusionsWhole-heart atherosclerosis progression examined by serial CCTA is independently associated with MACE, with a prognostic threshold of 1.0% increase in PAV per year.     

Consistency of quantitative analysis of coronary computed tomography angiography

BackgroundThe present study aimed to assess the reliability and reproducibility of coronary computed tomography angiography (CCTA) for the serial quantitative assessment of plaque volume.MethodsPatients who underwent repeated CCTA scans within 90 days were retrospectively screened and enrolled. Clinical data and CCTA imaging data were collected. Paired CCTA scans were analyzed using the quantitative method by separate observers blinded to the other paired CCTA scans. Results were compared between the index CCTA and follow-up CCTA.ResultsPaired CT scans of 95 patients (61 ± 13 years; 56.8% men) with same tube voltages (kVp) at both CCTAs and 24 patients (57 ± 19 years; 48.3% men) with different kVp at two CCTAs were analyzed. In patients with same kVp at both CCTAs, there were no difference in PV and PVs of each components in per-segment analysis and per-lesion analysis (all p > 0.05). In per-lesion analysis of CCTAs from patients who used different kVp between two CCTAs, lesion length, area and diameter stenosis, and PVs were not different between index and follow-up CCTAs (all p > 0.05). Segment length and PV were also showed no difference between two serial CCTAs in per-segment analysis.ConclusionWe showed the reproducibility and reliability of quantitative analysis of CCTA for assessment of coronary plaques. CCTA can be applied for the serial quantitative assessment of coronary artery disease progression, regardless of differences in the image acquisition protocol.     

The effect of patient and imaging characteristics on coronary CT angiography assessed pericoronary adipose tissue attenuation and gradient

BackgroundCoronary CT angiography (CCTA) pericoronary adipose tissue (PCAT) markers are promising indicators of inflammation.ObjectiveTo determine the effect of patient and imaging parameters on the associations between non-calcified plaque (NCP) and PCAT attenuation and gradient.MethodsThis was a single-center, retrospective analysis of consecutive patients with stable chest pain who underwent CCTA and had zero calcium scores. CCTA images were evaluated for the presence of NCP, obstructive stenosis, segment stenosis and involvement score (SSS, SIS), and high-risk plaque (HRP). PCAT markers were assessed using semi-automated software. Uni- and multivariable regression models correcting for patient and imaging characteristics between plaque and PCAT markers were evaluated.ResultsOverall, 1652 patients had zero calcium score (mean age: 51 years ?± ?11 [SD], 871 women); PCAT attenuation values ranged between ?123 HU and ?51 HU, and 649 patients had plaque. In univariable analysis, the presence of NCP, SSS, SIS, and HRP were associated with PCAT attenuation (2, 1, 1, 6 HU; respectively; p ?< ?.001 all); while obstructive stenosis was not (1 HU, p ?= ?.58). In multivariable analysis, none of the plaque markers were associated with PCAT attenuation (0 HU p ?= ?.93, 0 HU p ?= ?.39, 1 HU p ?= ?.18, 2 HU p ?= ?.10, 1 HU p ?= ?.71, respectively), while patient and imaging characteristics showed significant associations, such as: male sex (1 HU, p ?= ?.003), heart rate [1/min] (?0.2 HU, p ?< ?.001), 120 ?kVp (8 HU, p ?< ?.001) and pixel spacing [mm³] (32 HU, p ?< ?.001). Similar results were observed for PCAT gradient.ConclusionPCAT markers were significantly associated with NCP, however the associations did not persist following correction for patient and imaging characteristics.     

Comparison of professional medical society guidelines for appropriate use of coronary computed tomography angiography

BackgroundMultiple appropriate use criteria (AUC) exist for the evaluation of coronary artery disease (CAD), but there is little data on the agreement between AUC from different professional medical societies. The aim of this study is to compare the appropriateness of coronary computed tomography angiography (CCTA) exams assessed using multimodality AUC from the American College of Cardiology Foundation (ACCF) versus the American College of Radiology (ACR).MethodsIn a single-center prospective cohort study from June 2014 to 2016, 1005 consecutive subjects referred for evaluation of known or suspected CAD received a contrast-enhanced CCTA. The primary outcome was the agreement of appropriateness ratings using ACCF and ACR guidelines, measured by the kappa statistic. A secondary outcome was the rate of obstructive CAD by appropriateness rating.ResultsAmong 1005 subjects, the median (5–95th percentile) age was 59 (37–76) years with 59.0% male. The ACCF criteria classified 39.6% (n = 398) appropriate, 24.2% (n = 243) maybe appropriate, and 36.2% (n = 364) rarely appropriate. The ACR guidelines classified 72.3% (n = 727) appropriate, 2.6% (n = 26) maybe appropriate, and 25.1% (n = 252) rarely appropriate. ACCF and ACR appropriateness ratings were in agreement for 55.0% (n = 553). Overall, there was poor agreement (kappa 0.27 [95% confidence interval 0.23–0.31]). By both AUC methods, a low rate of obstructive CAD was observed in the rarely appropriate exams (ACCF 7.1% [n = 26 of 364] and ACR 13.5% [n = 34 of 252]).ConclusionsCompared to ACCF criteria, the ACR guidelines of appropriateness were broader and classified significantly more CCTA exams as appropriate. The poor agreement between appropriateness ratings from the ACCF and ACR AUC guidelines evokes implications for reimbursement and future test utilization.     

Increased coronary pericoronary adipose tissue attenuation in diabetic patients compared to non-diabetic controls: A propensity score matching analysis

BackgroundPericoronary adipose tissue (PCAT) attenuation is an indicator of active inflammation of perivascular adipose tissue, which is supposed to increase in diabetic patients. We aimed to investigate the PCAT attenuation values and high-risk plaque (HRP) features in diabetic and non-diabetic subjects with different stenotic extents.MethodsConsecutive type 2 diabetes patients and non-diabetic patients with chest pain and intermediate pre-test probability of coronary artery disease (CAD) were prospectively enrolled and underwent coronary computed tomography angiography (CCTA). At per-patient level, PCAT attenuation values of three major epicardial coronary vessels, as well as HRP features were measured. PCAT attenuation values and HRP features were compared between diabetic and non-diabetic subjects according to the presence or absence of obstructive stenosis.Results1700 patients (mean age: 65.5 ?± ?11.7, 940 males) were divided into two groups according to presence of obstructive stenosis on CCTA. Propensity score matching was performed in further analysis. RCA_PCAT was significantly higher in diabetic subjects than that in non-diabetic subjects, regardless of the presence of obstructive stenosis (?83.60 ?± ?9.51 HU vs. ?88.58 ?± ?9.37 HU, p ?< ?0.001) or absence of obstructive stenosis (?83.70 ?± ?10.32 HU vs. ?88.76 ?± ?8.28 HU, p ?< ?0.001). In contrast, HRP features were more commonly presented in diabetic patients with obstructive stenosis than in those without obstructive stenosis. According to subgroup analysis based on acquisition tube voltage, RCA_PCAT was the only parameter showing consistent difference between diabetic and non-diabetic patients.ConclusionsRCA_PCAT was significantly higher in diabetic patients than that in non-diabetic patients regardless of stenotic severity and plaque vulnerability.     

How accurate is atherosclerosis imaging by coronary computed tomography angiography?

Invasive coronary plaque imaging such as intravascular ultrasound and optical coherence tomography has been widely used to observe culprit or non-culprit coronary atherosclerosis, as well as optimize stent sizing, apposition and deployment. Coronary computed tomographic angiography (CTA) is non-invasively available to assess coronary artery disease (CAD) and has become an appropriate strategy to evaluate patients with suspected CAD. Given recent technologies, semi-automated plaque software is available to identify coronary plaque stenosis, volume and characteristics and potentially allows to be used for the assessment of more details of plaque information, progression and future risk as a surrogate tool of the invasive imaging modalities. This review article aims to focus on various evidence in coronary plaque imaging by coronary CTA and describes how accurate coronary CTA can classify coronary atherosclerosis.     

Debates in cardiac CT: Coronary CT angiography is the best test in asymptomatic patients

Cardiovascular disease remains a major cause of mortality, accounting for a third of all global deaths annually. Although there have been major improvements in our ability to detect and to treat patients with coronary heart disease, most myocardial infarctions occur in previously asymptomatic individuals. Identification of individuals at risk of myocardial infarction remains challenging and primary prevention guidelines rely on the use of cardiovascular risk scores that can be supplemented by coronary artery calcium scores. Coronary artery calcium scores provide a simple surrogate late marker of atherosclerosis but is unable to identify the early high risk non-calcified plaque which can be particularly problematic in younger individuals. Coronary computed tomography angiography is increasingly being used as the imaging strategy of choice in patients with symptoms of coronary heart disease. As an anatomical test, it can non-invasively detect the presence of coronary atherosclerosis, providing clinicians with a strong mandate to commence symptom relieving and preventative therapies. For asymptomatic individuals, it allows precise targeting of therapies to those with coronary heart disease rather than those “at risk” of disease. Moreover, our ability to calculate risk using coronary computed tomography angiography is rapidly improving with the use of techniques, such as plaque quantification and characterisation. These techniques have the potential to provide clinicians with tools to target cardiovascular disease prevention in a precision medicine approach. We here debate the ways in which coronary computed tomography angiography could improve the selection of asymptomatic individuals for preventative therapies over and above risk calculators and calcium scoring.     

Cumulative exposure amount of PM2.5 in the ambient air is associated with coronary atherosclerosis - Serial coronary CT angiography study

BackgroundWe investigated the change of coronary atherosclerosis with long-term exposure to fine particulate matter of aerodynamic diameter <2.5 ?μm (PM_2.5) using coronary computed tomography angiography (CCTA).MethodsSubjects undergoing serial CCTAs between January 2007 and December 2017 (n ?= ?3,127) were analyzed. Each individual's cumulative amount of PM_2.5 exposure between the two CCTAs was evaluated by Kriging interpolation and zonal analysis, considering the time interval between the two CCTAs. The main outcome was progression of coronary artery calcium (CAC) with additional semiquantitative analysis on the changes in the severity and composition of atherosclerotic plaques.ResultsThe CAC scores increased by 30.8 Agatston units per-year under a median PM_2.5 concentration 24.9 ?μg/m³ and tended to increase with the cumulative amount of PM_2.5 exposure (r ?= ?0.321, p ?<0.001). The CAC progressed in 1,361 (43.5%) subjects during a median 53 months follow-up. The cumulative amount of PM_2.5 exposure was independently associated with CAC progression (adjusted OR 1.09, p ?<0.001). By random forest analysis, the relative impact of cumulative amount of PM_2.5 exposure on CAC progression was higher than that of traditional cardiovascular risk factors and the average concentration of PM_2.5. The extent of coronary atherosclerosis and newly developed calcified plaque on follow-up were also significantly associated with the cumulative amount of PM_2.5 exposure.ConclusionsCumulative exposure to air pollution is associated with the progression of diffuse coronary calcification, the importance of which may be more significant than other traditional cardiovascular risk factors. Further investigations into the causality between PM_2.5 and coronary atherosclerosis are warranted to improve global cardiovascular health.     

Sex- and age-specific differences in the long-term prognostic value of morphological plaque features detected by coronary computed tomography angiography

BackgroundAlthough sex- and age-specific differences in coronary plaque features detected by coronary computed tomography angiography (CCTA) are known, insufficient information regarding the long-term prognostic value of these findings exists.MethodsA total of 1615 patients with suspected but not previously diagnosed coronary artery disease (CAD) were examined by CCTA and coronary plaque features were assessed. The median follow-up period was 10.5 (IQR 9.2–11.4) years. Cox proportional-hazards analysis was used for the combined endpoint of cardiac death or nonfatal myocardial infarction.ResultsThe endpoint occurred more often in patients older than 65 years (5.66% vs. 2.05%; p = 0.00029) but similarly between female (3.34%) and male (3.07%) patients (p = 0.76). Both sexes displayed a similar prevalence for noncalcified (female vs. male: 0.77 ± 1.38 vs. 0.89 ± 1.41; p = 0.098) and low-attenuation (female vs. male: 2.6% vs. 4.37%; p = 0.096) plaques. As assessed by p for interaction CADRADS (p for interaction = 0.013), noncalcified plaques (p for interaction = 0.022) and low-attenuation plaques (p for interaction = 0.045) had a better primary endpoint association in women than in men. Concerning age, no difference in outcome association was apparent as evaluated by p for interaction.ConclusionCCTA demonstrates excellent long-term prognostic value irrespective of sex and age and independent from the higher prevalence of atherosclerotic plaques in men and patients older than 65 years. Although similarly prevalent in both sexes, noncalcified and low-attenuation plaques exhibit a better prognostic value in women.     

Prognostic value of myocardial perfusion imaging after first-line coronary computed tomography angiography: A multi-center cohort study

PurposeFurther diagnostic testing may be required after a coronary computed tomography angiography (CTA) showing suspected coronary stenosis. Whether myocardial perfusion imaging (MPI) provides further prognostic information post-CTA remains debated. We evaluated the prognosis for patients completing CTA stratified for post-CTA diagnostic work-up using real-world data.MethodsWe identified all patients in our uptake area with angina symptoms undergoing first-time CTA over a 10-year period. Follow-up time was a median of 3.7 years [1.9–5.8]. The primary endpoint was a composite of myocardial infarction or death. The secondary endpoint was late revascularization.ResultsDuring the study period 53,351 patients underwent CTA. Of these, 24% were referred for further down-stream testing, 3,547 (7%) to MPI and 9,135 (17%) to invasive coronary angiography (ICA). The primary and secondary endpoints occurred in 2,026 (3.8%) and 954 (1.8%) patients. Patient-characteristic-adjusted hazard ratios for the primary and secondary endpoint using patients with a normal CTA as reference were 1.37 (1.21–1.55) and 2.50 (1.93–3.23) for patient treated medically, 1.68 (1.39–2.03) and 6.13 (4.58–8.21) for patients referred to MPI and 1.94 (1.69–2.23) and 9.18 (7.16–11.78) for patients referred for ICA, respectively. Adjusted analysis with stratification for disease severity at CTA showed similar hazard ratios for patients treated medically after CTA and patients referred for MPI and treated medically after the MPI.ConclusionIn patients completing coronary CTA, second-line MPI testing seems to identify patients at low risk of future events. MPI seems to have the potential to act as gatekeeper for ICA after coronary CTA.     

Comparison of coronary CT angiography-based and invasive coronary angiography-based quantitative flow ratio for functional assessment of coronary stenosis: A multicenter retrospective analysis

BackgroundThe aim of this study was to evaluate the diagnostic performance of coronary CT angiography (CTA)-based quantitative flow ratio (QFR), namely CT-QFR, and compare it with invasive coronary angiography (ICA)-based Murray law QFR (μQFR), using fractional flow reserve (FFR) as the reference standard.MethodsPatients who underwent coronary CTA, ICA and pressure wire-based FFR assessment within two months were retrospectively analyzed. CT-QFR and μQFR were computed in blinded fashion and compared with FFR, all applying the same cut-off value of ≤0.80 to identify hemodynamically significant stenosis.ResultsPaired comparison between CT-QFR and μQFR was performed in 191 vessels from 167 patients. Average FFR was 0.81 ?± ?0.10 and 42.4% vessels had an FFR ≤0.80. CT-QFR had a slightly lower correlation with FFR compared with μQFR, although statistically non-significant (r ?= ?0.87 versus 0.90, p ?= ?0.110). The vessel-level diagnostic performance of CT-QFR was slightly lower but without statistical significance than μQFR (AUC ?= ?0.94 versus 0.97, difference: ?0.03 [95%CI: ?0.00-0.06], p ?= ?0.095), and substantially higher than diameter stenosis by CTA (AUC difference: 0.17 [95%CI: ?0.10-0.23], p ?< ?0.001). The patient-level diagnostic accuracy, sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio and negative likelihood ratio for CT-QFR to identify FFR value ?≤ ?0.80 was 88%, 90%, 86%, 86%, 91%, 6.59 and 0.12, respectively. The diagnostic accuracy of CT-QFR was 84% in extensively calcified lesions, while in vessels with no or less calcification, CT-QFR showed a comparable diagnostic accuracy with μQFR (91% versus 92%, p ?= ?0.595). Intra- and inter-observer variability in CT-QFR analysis was ?0.00 ?± ?0.04 and 0.00 ?± ?0.04, respectively.ConclusionsPerformance in diagnosis of hemodynamically significant coronary stenosis by CT-QFR was slightly lower but without statistical significance than μQFR, and substantially higher than CTA-derived diameter stenosis. Extensively calcified lesions reduced the diagnostic accuracy of CT-QFR.     

Influence of coronary stenosis location on diagnostic performance of machine learning-based fractional flow reserve from CT angiography

BackgroundCompared with invasive fractional flow reserve (FFR), coronary CT angiography (cCTA) is limited in detecting hemodynamically relevant lesions. cCTA-based FFR (CT-FFR) is an approach to overcome this insufficiency by use of computational fluid dynamics. Applying recent innovations in computer science, a machine learning (ML) method for CT-FFR derivation was introduced and showed improved diagnostic performance compared to cCTA alone. We sought to investigate the influence of stenosis location in the coronary artery system on the performance of ML-CT-FFR in a large, multicenter cohort.MethodsThree hundred and thirty patients (75.2% male, median age 63 years) with 502 coronary artery stenoses were included in this substudy of the MACHINE (Machine Learning Based CT Angiography Derived FFR: A Multi-Center Registry) registry. Correlation of ML-CT-FFR with the invasive reference standard FFR was assessed and pooled diagnostic performance of ML-CT-FFR and cCTA was determined separately for the following stenosis locations: RCA, LAD, LCX, proximal, middle, and distal vessel segments.ResultsML-CT-FFR correlated well with invasive FFR across the different stenosis locations. Per-lesion analysis revealed improved diagnostic accuracy of ML-CT-FFR compared with conventional cCTA for stenoses in the RCA (71.8% [95% confidence interval, 63.0%–79.5%] vs. 54.8% [45.7%–63.8%]), LAD (79.3 [73.9–84.0] vs. 59.6 [53.5–65.6]), LCX (84.1 [76.0–90.3] vs. 63.7 [54.1–72.6]), proximal (81.5 [74.6–87.1] vs. 63.8 [55.9–71.2]), middle (81.2 [75.7–85.9] vs. 59.4 [53.0–65.6]) and distal stenosis location (67.4 [57.0–76.6] vs. 51.6 [41.1–62.0]).ConclusionIn a multicenter cohort with high disease prevalence, ML-CT-FFR offered improved diagnostic performance over cCTA for detecting hemodynamically relevant stenoses regardless of their location.     

A novel density-volume calcium score by non-contrast CT predicts coronary plaque burden on coronary CT angiography: Results from the MACS (Multicenter AIDS cohort study)

BackgroundThe purpose of this study is to determine if a new score calculated with coronary artery calcium (CAC) density and volume is associated with total coronary artery plaque burden and composition on coronary CT angiography (CCTA) compared to the Agatston score (AS).MethodsWe identified 347 men enrolled in the Multicenter AIDS cohort study who underwent contrast and non-contrast CCTs, and had CAC>0. CAC densities (mean Hounsfield Units [HU]) per plaque) and volumes on non-contrast CCT were measured. A Density-Volume Calcium score was calculated by multiplying the plaque volume by a factor based on the mean HU of the plaque (4, 3, 2 and 1 for 130–199, 200–299, 300–399, and ≥400HU). Total Density-Volume Calcium score was determined by the sum of these individual scores. The semi-quantitative partially calcified and total plaque scores (PCPS and TPS) on CCTA were calculated. The associations between Density-Volume Calcium score, PCPS and TPS were examined.ResultsOverall, 2879 CAC plaques were assessed. Multivariable linear regression models demonstrated a stronger association between the log Density-Volume Calcium score and both the PCPS (β 0.99, 95%CI 0.80–1.19) and TPS (β 2.15, 95%CI 1.88–2.42) compared to the log of AS (PCPS: β 0.77, 95%CI 0.61–0.94; TPS: β 1.70, 95%CI 1.48–1.94). Similar results were observed for numbers of PC or TP segments.ConclusionThe new CAC score weighted towards lower density demonstrated improved correlation with semi-quantitative PC and TP burden on CCTA compared to the traditional AS, which suggests it has utility as an alternative measure of atherosclerotic burden.     

Detection of small coronary calcifications in patients with Agatston coronary artery calcium score of zero

BackgroundA coronary artery calcium score (CACS) of 0 is associated with a very low risk of cardiac event. However, the Agatston CACS may fail to detect very small or less dense calcifications. We investigated if an alteration of the Agatston criteria would affect the ability to detect such plaques.MethodsWe evaluated 322 patients, 161 who had a baseline scan with CACS ?= ?0 and a follow-up scan with CACS>0 and 161 with two serial CACS ?= ?0 scans (control group), to identify subtle calcification not detected in the baseline scan because it was not meeting the Agatston size and HU thresholds (≥1 ?mm² and ≥130HU). Size threshold was set to <1 ?mm² and the HU threshold modified in a stepwise manner to 120, 110, 100 and 90. New lesions were classified as true positive or false positive(noise) using the follow-up scan.ResultsWe identified 69 visually suspected subtle calcified lesions in 65/322 (20.2%) patients with CAC ?= ?0 by the Agatston criteria. When size threshold was set as <1 ?mm² and HU ?≥ ?130, 36 lesions scored CACS>0, 34 (94.4%) true positive and 2 (5.6%) false positive. When decrease in HU (120HU, 110HU, 100HU, and 90HU) threshold was added to the reduced size threshold, the number of lesions scoring>0 increased (46, 55, 59, and 69, respectively) at a cost of increased false positive rate (8.7%, 20%, 22%, and 30.4% respectively). Eliminating size or both size and HU threshold to ≥120HU correctly reclassified 9.6% and 12.1% of patients respectively.ConclusionEliminating size and reducing HU thresholds to ≥120HU improved the detection of subtle calcification when compared to the Agatston CACS method.