Evaluation of epicardial coronary resistance using computed tomography angiography: A Proof of Concept

AimsFractional flow reserve (FFR) pullback allows to assess the distribution of pressure loss along the coronary vessels. FFR derived from CT (FFRCT) provides a virtual pullback curve that may also aid in the assessment of the distribution of epicardial coronary resistance in the non-invasive setting. The present study aims to determine the accuracy of the virtual FFR_CT pullback curve using a motorized invasive FFR pullback as reference in patients with stable coronary artery disease.Methods and resultsFFR values were extracted from coronary vessels at approximately 1 mm to generate pullback curves. Invasive motorized FFR pullbacks were acquired using a dedicated device at a speed of 1 mm/s. A total of 3172 matched FFR_CT and FFR values were obtained in 24 vessels. The correlation coefficient between FFR_CT and FFR was 0.76 (95%CI 0.75 to 0.78; p < 0.001). The area under the pullback curve was similar between FFR_CT and invasive FFR (79.0 ± 16.1 vs. 85.3 ± 16.4, p = 0.097). The mean difference in lesion gradient between FFR_CT and FFR was −0.07 (LOA -0.26 to 0.13) whereas in non-obstructive segments was −0.01 (LOA -0.06 to 0.05).ConclusionThe evaluation of epicardial coronary resistance using coronary CT angiography with FFR_CT was feasible. FFR_CT virtual pullback appears to be accurate for the evaluation of pressure gradients. FFR_CT has the potential to identify the pathophysiological pattern of coronary artery disease in the non-invasive setting.     

Diagnostic concordance and discordance between angiography-based quantitative flow ratio and fractional flow reserve derived from computed tomography in complex coronary artery disease

BackgroundBoth quantitative flow ratio (QFR) and fractional flow reserve derived from computed tomography (FFR_CT) have shown significant correlations with invasive wire-based fractional flow reserve. However, the correlation between QFR and FFR_CT is not fully investigated in patients with complex coronary artery disease (CAD). The aim of this study is to investigate the correlation and agreement between QFR and FFR_CT in patients with de novo three-vessel disease and/or left main CAD.MethodsThis is a post-hoc sub-analysis of the international, multicenter, and randomized SYNTAX III REVOLUTION trial, in which both invasive coronary angiography and coronary computed tomography angiography were prospectively obtained prior to the heart team discussion. QFR was performed in an independent core laboratory and compared with FFR_CT analyzed by HeartFlow?. The correlation and agreement between QFR and FFR_CT were assessed per vessel. Furthermore, independent factors of diagnostic discordance between QFR and FFR_CT were evaluated.ResultsOut of 223 patients, 40 patients were excluded from this analysis due to the unavailability of FFR_CT and/or QFR, and a total of 469 vessels (183 patients) were analyzed. There was a strong correlation between QFR and FFR_CT (R ?= ?0.759; p ?< ?0.001), and the Bland-Altman analysis demonstrated a mean difference of ?0.005 and a standard deviation of 0.116. An independent predictor of diagnostic concordance between QFR and FFR_CT was the lesion location in right coronary artery (RCA) (odds ratio 0.395; 95% confidence interval 0.174–0.894; P ?= ?0.026).ConclusionIn patients with complex CAD, QFR and FFR_CT were strongly correlated. The location of the lesion in RCA was associated with the highest diagnostic concordance between QFR and FFR_CT.     

Perivascular fat attenuation for predicting adverse cardiac events in stable patients undergoing invasive coronary angiography

BackgroundInflammation surrounding the coronary arteries can be non-invasively assessed using pericoronary adipose tissue attenuation (PCAT). While PCAT holds promise for further risk stratification of patients with low coronary artery disease (CAD) prevalence, its value in higher risk populations remains unknown.MethodsCORE320 enrolled patients referred for invasive coronary angiography with known or suspected CAD. Coronary computed tomography angiography (CCTA) images were collected for 381 patients for whom clinical outcomes were assessed 5 years after enrollment. Using semi-automated image analysis software, PCAT was obtained and normalized for the right coronary (RCA), left anterior descending (LAD), and left circumflex arteries (LCx). The association between PCAT and major adverse cardiovascular events (MACE) during follow up was assessed using Cox regression models.ResultsThirty-seven patients were excluded due to technical failure. For the remaining 344 patients, median age was 62 (interquartile range, 55–68) with 59% having ≥1 coronary artery stenosis of ≥50% by quantitative coronary angiography. Mean attenuation values for PCAT in RCA, LAD, and LCx were ?74.9, ?74.2, and ?71.2, respectively. Hazard ratios and 95% confidence intervals (CI) for normalized PCAT in the RCA, LAD, and LCx for MACE were 0.96 (CI: 0.75–1.22, p ?= ?0.71), 1.31 (95% CI: 0.96–1.78, p ?= ?0.09), and 0.98 (95% CI: 0.78–1.22, p ?= ?0.84), respectively. For death, stroke, or myocardial infarction only, hazard ratios were 0.68 (0.44–1.07), 0.85 (0.56–1.29), and 0.57 (0.41–0.80), respectively.ConclusionsIn patients referred for invasive coronary angiography with suspected CAD, PCAT did not predict MACE during long term follow up. Further studies are needed to understand the relationship of PCAT with CAD risk.     

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 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.     

Fractional flow reserve derived from coronary CT angiography: Variation of repeated analyses

BackgroundFractional flow reserve (FFR) is the standard of reference for assessing the hemodynamic significance of coronary stenoses in patients with stable coronary artery disease. Noninvasive FFR derived from coronary CT angiography (FFR_CT) is a promising new noninvasive method for assessing the physiologic significance of epicardial stenoses. The reproducibility of FFR_CT has not yet been established.ObjectiveThe aim of this study was to evaluate the variation of repeated analyses of FFR_CT per se and in the context of the reproducibility of repeated FFR measurements.MethodsCoronary CT angiography and invasive coronary angiography with repeated FFR measurements were performed in 28 patients (58 vessels) with suspected stable coronary artery disease. Based on the coronary CT angiography data set, FFR_CT analyses were performed twice by 2 independent blinded analysts.ResultsIn 12 of 58 (21%) vessels FFR was ≤0.80. The standard deviation for the difference between first and second FFR_CT analyses was 0.034 vs 0.033 for FFR repeated measurements (P = .722). Limits of agreement were −0.06 to 0.08 for FFR_CT and −0.07 to 0.06 for FFR. The coefficient of variation of FFR_CT (CV_FFRct) was 3.4% (95% confidence interval [CI], 1.4%–4.6%) vs 2.7% (95% CI, 1.8%–3.3%) for FFR. In vessels with mean FFR ranging between 0.70 and 0.90 (n = 25), the difference between the first and second FFR_CT analyses was 0.035 and FFR repeated measurements was 0.043 (P = .357), whereas CV_FFRct was 3.3% (95% CI, 1.5%–4.3%) and coefficient of variation for FFR was 3.6% (95% CI, 2.3%–4.6%).ConclusionsThe reproducibility of both repeated FFR_CT analyses and repeated FFR measurements is high.     

Optimized interpretation of fractional flow reserve derived from computed tomography: Comparison of three interpretation methods

BackgroundAn optimal system for interpreting fractional flow reserve (FFR) values derived from CT (FFRCT) is lacking. We sought to evaluate performance of three FFR_CT measurements in detecting ischemia by comparing them with invasive FFR.MethodsFor 73 vessels in 50 patients who underwent coronary CT angiography (CCTA) and FFR_CT analysis followed by invasive FFR, the greatest diameter stenosis on CCTA, FFR_CT difference between distal and proximal to the stenosis (ΔFFR_CT), FFR_CT 2 cm distal to the stenosis (lesion-specific FFR_CT), and the lowest FFR_CT in distal vessel tip were calculated. Significant obstruction (≥50% diameter stenosis) and ischemia (lesion-specific FFR_CT ≤0.80, the lowest FFR_CT ≤0.80, or ΔFFR_CT ≥0.12 based on the greatest Youden index) were compared with invasive FFR (≤0.80).ResultsForty (55%) vessels demonstrated ischemia during invasive FFR. On multivariable generalized estimating equations, ΔFFR_CT (odds ratio [OR] 10.2, p < 0.01) remained a predictor of ischemia over CCTA (OR 2.9), lesion-specific FFR_CT (OR 3.1), and the lowest FFR_CT (OR 0.9) (p > 0.05 for all). Area under the curve (AUC) of ΔFFR_CT (0.86) was higher than CCTA (0.66), lesion-specific FFR_CT (0.71), and the lowest FFR_CT (0.65) (p < 0.01 for all). Addition of each FFR_CT measure to CCTA showed improvement of AUC and significant net reclassification improvement (NRI): ΔFFR_CT (AUC 0.84, NRI 1.24); lesion-specific FFR_CT (AUC 0.77, NRI 0.83); and the lowest FFR_CT (AUC 0.76, NRI 0.59) (p < 0.01 for all).ConclusionsCompared with diameter stenosis, ΔFFR_CT, lesion-specific FFR_CT, and the lowest FFR_CT improved ischemia discrimination and reclassification, with ΔFFR_CT being superior in identifying and discriminating ischemia.     

A comparative assessment of the performance of a state-of-the art small footprint dedicated cardiovascular CT scanner

IntroductionWith increasing adoption of CT coronary angiography (CTA) there is increasing demand for cost-effective, small footprint, dedicated cardiac scanners. We compared a state-of-the-art, small footprint dedicated cardiac scanner (DCCT) to a standard multidetector scanner (MDCT).MethodsThe study was a retrospective unblinded single centre study. A total of 800 patients were included, with 400 undergoing a DCCT and MDCT coronary CTA scanning, respectively. Image quality was assessed using a 4-point grading score. Image noise and artifact, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR), and acceptance rate for CT-derived fractional flow reserve (FFRct) were recorded.ResultsOverall image quality was higher in the DCCT group (3.8 ± 0.55 vs 3.6 ± 0.69; p = 0.042). There was no difference in overall image noise (p = 0.131) or artifact (p = 0.295). SNR was superior in the DCCT group (14.2 ± 6.85 vs 11.4 ± 3.32; p < 0.005) as was CNR (12.7 ± 6.77 vs 11.9 ± 3.29; p < 0.005). The heart rate was lower in the DCCT group (56 ± 9.1 vs 59 ± 8.1; p < 0.005). No difference in the dose length product (DLP median 244.53 (IQR 105.6) vs 237.63 (IQR 160.1); p = 0.313) or FFR_CT acceptance rate (100 vs 97.7%; p > 0.05) was noted. Independent predictors of excellent quality regardless of scanner type were age (p = 0.011), heart rate <65 bpm (p < 0.005), and body mass index < 35 (p < 0.005).ConclusionA DCCT scanner is capable of image quality similar to modern current generation general purpose CT technology. Such technology appears to be a viable option to serve the increasing demand for CTCA imaging.     

CT assessment of the left atrial appendage post-transcatheter occlusion – A systematic review and meta analysis

BackgroundTransesophageal echocardiography (TEE) is the standard imaging modality used to assess the left atrial appendage (LAA) after transcatheter device occlusion. Cardiac computed tomography angiography (CCTA) offers an alternative non-invasive modality in these patients. We aimed to conduct a comparison of the two modalities.MethodsWe performed a comprehensive systematic review of the current literature pertaining to CCTA to establish its usefulness during follow-up for patients undergoing LAA device closure. Studies that reported the prevalence of inadequate LAA closure on both CCTA and TEE were further evaluated in a meta-analysis. 19 studies were used in the systematic review, and six studies were used in the meta-analysis.ResultsThe use of CCTA was associated with a higher likelihood of detecting LAA patency than the use of TEE (OR, 2.79, 95% CI 1.34–5.80, p ?= ?0.006, I² ?= ?70.4%). There was no significant difference in the prevalence of peridevice gap ≥5 ?mm (OR, 3.04, 95% CI 0.70–13.17, p ?= ?0.13, I² ?= ?0%) between the two modalities. Studies that reported LAA assessment in early and delayed phase techniques detected a 25%–50% higher prevalence of LAA patency on the delayed imaging.ConclusionCCTA can be used as an alternative to TEE for LAA assessment post occlusion. Standardized CCTA acquisition and interpretation protocols should be developed for clinical practice.     

Importance of measurement site on assessment of lesion-specific ischemia and diagnostic performance by coronary computed tomography Angiography-Derived Fractional Flow Reserve

BackgroundValues of fractional flow reserve (FFR_CT) by coronary computed tomography angiography (CTA) decline from the ostium to the terminal vessel, irrespective of stenosis severity. The purpose of this study is to determine if the site of measurement of FFR_CT impacts assessment of ischemia and its diagnostic performance relative to invasive FFR (FFR_INV).Methods1484 patients underwent FFR_CT; 1910 vessels were stratified by stenosis severity (normal; <25%, 25–50%, 50–70%, and >70% stenosis). The rates of positive FFR_CT (≤0.8) were determined by measuring FFR_CT from the terminal vessel and from distal-to-the-lesion. Reclassification rates from positive to negative FFR_CT were calculated. Diagnostic performance of FFR_CT relative to FFR_INV was evaluated in 182 vessels using linear regression, Bland Altman analysis, and receiver operating characteristic (ROC) curves.ResultsPositive FFR_CT was identified in 24.9% of vessels using terminal vessel FFR_CT and 10.1% using FFR_CT distal-to-the-lesion (p ?< ?0.001). FFR_CT obtained distal-to-the-lesion resulted in reclassification of 59.6% of positive terminal FFR_CT to negative FFR_CT. Relative to FFR_INV, there were improvements in specificity (50% to 86%, p ?< ?0.001), diagnostic accuracy (65% to 88%, p ?< ?0.001), positive predictive value (50% to 78%, p ?< ?0.001), and area-under-the-curve (AUC, 0.83 to 0.91, p ?< ?0.001) when FFR_CT was measured distal-to-the-lesion.ConclusionFFR_CT values from the terminal vessel should not be used to assess lesion-specific ischemia due to high rates of false positive results. FFR_CT measured distal-to-the-lesion improves the diagnostic performance of FFR_CT relative to FFR_INV, ensures that FFR_CT values are due to lesion-specific ischemia, and could reduce the rate of unnecessary invasive procedures.     

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.     

Impact of membranous septum length on pacemaker need with different transcatheter aortic valve replacement systems: The INTERSECT registry

BackgroundNew permanent pacemaker implantation (new-PPI) remains a compelling issue after Transcatheter Aortic Valve Replacement (TAVR). Previous studies reported the relationship between a short MS length and the new-PPI post-TAVR with a self-expanding THV. However, this relationship has not been investigated in different currently available THV. Therefore, the aim of this study was to investigate the association between membranous septum (MS)-length and new-PPI after TAVR with different Transcatheter Heart Valve (THV)-platforms.MethodsWe included patients with a successful TAVR-procedure and an analyzable pre-procedural multi-slice computed tomography. MS-length was measured using a standardized methodology. The primary endpoint was the need for new-PPI within 30 days after TAVR.ResultsIn total, 1811 patients were enrolled (median age 81.9 years [IQR 77.2–85.4], 54% male). PPI was required in 275 patients (15.2%) and included respectively 14.2%, 20.7% and 6.3% for Sapien3, Evolut and ACURATE-THV(p ?< ?0.01).Median MS-length was significantly shorter in patients with a new-PPI (3.7 ?mm [IQR 2.2–5.1] vs. 4.1 ?mm [IQR 2.8–6.0], p ?= ?<0.01). Shorter MS-length was a predictor for PPI in patients receiving a Sapien3 (OR 0.87 [95% CI 0.79–0.96], p ?= ?<0.01) and an Evolut-THV (OR 0.91 [95% CI 0.84–0.98], p ?= ?0.03), but not for an ACURATE-THV (OR 0.99 [95% CI 0.79–1.21], p ?= ?0.91). By multivariable analysis, first-degree atrioventricular-block (OR 2.01 [95% CI 1.35–3.00], p = <0.01), right bundle branch block (OR 8.33 [95% CI 5.21–13.33], p = <0.01), short MS-length (OR 0.89 [95% CI 0.83–0.97], p ?< ?0.01), annulus area (OR 1.003 [95% CI 1.001–1.005], p ?= ?0.04), NCC implantation depth (OR 1.13 [95% CI 1.07–1.19] and use of Evolut-THV(OR 1.54 [95% CI 1.03–2.27], p ?= ?0.04) were associated with new-PPI.ConclusionMS length was an independent predictor for PPI across different THV platforms, except for the ACURATE-THV. Based on our study observations within the total cohort, we identified 3 risk groups by MS length: MS length ≤3 ?mm defined a high-risk group for PPI (>20%), MS length 3–7 ?mm intermediate risk for PPI (10–20%) and MS length > 7 ?mm defined a low risk for PPI (<10%). Anatomy-tailored-THV-selection may mitigate the need for new-PPI in patients undergoing TAVR.     

Predictive value of the coronary artery calcium score and advanced plaque characteristics: Post hoc analysis of the PREDICT registry

BackgroundWhether coronary plaque characteristics assessed in coronary computed tomography angiography (CCTA) in association with the coronary artery calcium score (CACS) have predictive value for coronary events is unclear. We aimed to examine the predictive value of the CACS and plaque characteristics for the occurrence of coronary events.MethodsAmong 2802 patients who were analyzed in the PREDICT registry, 2083 with suspected coronary artery disease (CAD) were studied using post hoc analysis. High-risk plaques were defined as having ≥2 adverse characteristics, such as low computed tomographic attenuation, positive remodeling, spotty calcification, and napkin-ring sign. An adjudicative composite of coronary events (cardiac death, nonfatal acute coronary syndrome, and coronary revascularization ≥3 months after indexed CCTA) were analyzed.ResultsSeventy-three (3.5%) patients had coronary events and 313 (15.0%) had high-risk plaques. Multivariate Cox proportional hazard analysis showed that high-risk plaques remained an independent predictor of coronary events (adjusted hazard ratio [HR] 1.95, 95% confidence interval [CI] 1.13–3.34, P ?= ?0.0154), as well as the log-transformed CACS (adjusted HR 1.24, 95% CI 1.11–1.39, P ?= ?0.0002) and the presence of obstructive stenosis (adjusted HR 5.63, 95% CI 3.22–10.12, P 0.0001). In subgroup analyses, high-risk plaques were independently predictive only in the low CACS class (<100).ConclusionThis study shows that assessment of adverse features by coronary plaque imaging independently predicts coronary events in patients with suspected CAD and a low CACS. Our findings suggest that the clinical value of high-risk plaques to CACS and stenosis assessment appears marginal.     

Higher coronary artery calcium score is associated with increased risk of atrial fibrillation recurrence after catheter ablation

BackgroundCoronary artery calcium score (CACS) is associated with an increased risk of atrial fibrillation (AF) development, but scarce data are available regarding the impact on AF recurrence. This study aims to assess the impact of CACS on AF recurrence following catheter ablation.MethodsRetrospective study of patients with AF undergoing cardiac computed tomography (CCT) before ablation (2017–2019). Patients with coronary artery disease (CAD), significant valvular heart disease and previous catheter ablation were excluded. A cut-off of CACS ≥ 100 was used according to literature.ResultsA total of 311 patients were included (median age 57 [48, 64] years, 65% men and 21% with persistent AF). More than half of the patients had a CACS > 0 (52%) and 18% a CACS ≥ 100. Patients with CACS ≥ 100 were older (64 [59, 69] vs 55 [46, 63] years, p ?< ?0.001), had more frequently hypertension (68% vs 42%, p ?< ?0.001) and diabetes mellitus (21% vs 10%, p ?= ?0.020). During a median follow-up of 34 months (12–57 months), 98 patients (32%) had AF recurrence. CACS ≥ 100 was associated with increased risk of AF recurrence (unadjusted Cox regression: hazard ratio [HR] 2.0; 95% confidence interval [CI], 1.3–3.1, p ?= ?0.002). After covariate adjustment, CACS ≥ 100 and persistent AF remained independent predictors of AF recurrence (HR, 1.7; 95% CI, 1.0–2.8, p ?= ?0.039 and HR, 2.0; 95% CI, 1.3–3.2, p ?= ?0.004, respectively).ConclusionAn opportunistic evaluation of CACS could be an important tool to improve clinical care considering that CACS ≥ 100 was independently associated with a 69% increase in the risk of AF recurrence after first catheter ablation.     

Patient-specific computer simulation to predict long-term outcomes after transcatheter aortic valve replacement

BackgroundPatient-specific computer simulation may predict the development of paravalvular regurgitation (PVR) after transcatheter aortic valve replacement (TAVR). We hypothesised that patient-specific computer simulation might identify patients at risk for long-term adverse outcomes after TAVR.MethodsA multi-centre retrospective study was performed on patients with symptomatic severe aortic stenosis who had undergone TAVR with a self-expanding transcatheter heart valve (THV). Pre-procedural cardiac computed tomography imaging was used to create finite element models of the aortic root. Finite element analysis (FEA) was performed in order to simulate the interaction between the THV and the native anatomy. The blood domain was extracted from the FEA output and computational fluid dynamics (CFD) simulation undertaken. Predicted PVR was recorded in the left ventricular outflow tract. Patients were classified into those where computer simulation predicted no significant PVR (predicted PVR from CFD <16.0 ?mL/s) and those where computer simulation predicted significant PVR (predicted PVR from CFD ≥16.0 ?mL/s).ResultsA total of 203 patients were included in the study. THVs implanted were CoreValve (n ?= ?20), Evolut R (n ?= ?90) and Evolut PRO (n ?= ?93). At 2 years, the Kaplan-Meier estimate of the rate of death from any cause was higher in the group where CFD simulation predicted significant PVR (35.8% vs. 16.3%; hazard ratio, 2.62; 95% confidence interval, 1.29 to 5.30; P ?= ?0.006 by log-rank test).ConclusionsComputer simulation may identify patients who are at a higher risk for death after TAVR.     

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.     

The direct costs of coronary CT angiography relative to contrast-enhanced thoracic CT: Time-driven activity-based costing

BackgroundCoronary CT angiography (CCTA) and contrast-enhanced thoracic CT (CECT) are distinctly different diagnostic procedures that involve intravenous contrast-enhanced CT of the chest. The technical component of these procedures is reimbursed at the same rate by the Centers for Medicare and Medicaid Services (CMS). This study tests the hypothesis that the direct costs of performing these exams are significantly different.MethodsDirect costs for both procedures were measured using a time-driven activity-based costing (TDABC) model. The exams were segmented into four phases: preparation, scanning, post-scan monitoring, and image processing. Room occupancy and direct labor times were collected for scans of 54 patients (28 CCTA and 26 CECT studies), in seven medical facilities within the USA and used to impute labor and equipment cost. Contrast material costs were measured directly. Cost differences between the exams were analyzed for significance and variability.ResultsMean CCTA duration was 3.2 times longer than CECT (121 and 37 ​min, respectively. p ​< ​0.01). Mean CCTA direct costs were 3.4 times those of CECT ($189.52 and $55.28, respectively, p ​< ​0.01). Both labor and capital equipment costs for CCTA were significantly more expensive (6.5 and 1.8-fold greater, respectively, p ​< ​0.001). Segmented by procedural phase, CCTA was both longer and more expensive for each (p ​< ​0.01). Mean direct costs for CCTA exceeded the standard CMS technical reimbursement of $182.25 without accounting for indirect or overhead costs.ConclusionThe direct cost of performing CCTA is significantly higher than CECT, and thus reimbursement schedules that treat these procedures similarly undervalue the resources required to perform CCTA and possibly decrease access to the procedure.     

First-in-Human Study with Eight Patients Using an Absorbable Vena Cava Filter for the Prevention of Pulmonary Embolism

PurposeTo prospectively evaluate the initial human experience with an absorbable vena cava filter designed for transient protection from pulmonary embolism (PE).Materials and MethodsThis was a prospective, single-arm, first-in-human study of 8 patients with elevated risk of venous thromboembolism (VTE). Seven absorbable IVC filters (made of polydioxanone that breaks down into H₂O and CO₂ in 6 mo) were placed prophylactically before orthopedic (n = 5) and gynecologic (n = 2) surgeries, and 1 was placed in a case of deep vein thrombosis. Subjects underwent CT cavography and abdominal radiography before and 5, 11, and 36 weeks after filter placement to assess filter migration, embolization, perforation, and caval thrombosis and/or stenosis. Potential PE was assessed immediately before and 5 weeks after filter placement by pulmonary CT angiography.ResultsNo symptomatic PE was reported throughout the study or detected at the planned 5-week follow-up. No filter migration was detected based on the fixed location of the radiopaque markers (attached to the stent section of the filter) relative to the vertebral bodies. No filter embolization or caval perforation was detected, and no caval stenosis was observed. Throughout the study, no filter-related adverse events were reported.ConclusionsImplantation of an absorbable vena cava filter in a limited number of human subjects resulted in 100% clinical success. One planned deployment was aborted as a result of stenotic pelvic veins, resulting in 89% technical success. No PE or filter-related adverse events were observed.     

Mortality impact of low CAC density predominantly occurs in early atherosclerosis: explainable ML in the CAC consortium

BackgroundMachine learning (ML) models of risk prediction with coronary artery calcium (CAC) and CAC characteristics exhibit high performance, but are not inherently interpretable.ObjectivesTo determine the direction and magnitude of impact of CAC characteristics on 10-year all-cause mortality (ACM) with explainable ML.MethodsWe analyzed asymptomatic subjects in the CAC consortium. We trained ML models on 80% and tested on 20% of the data with XGBoost, using clinical characteristics ?+ ?CAC (ML 1) and additional CAC characteristics of CAC density and number of calcified vessels (ML 2). We applied SHAP, an explainable ML tool, to explore the relationship of CAC and CAC characteristics with 10-year all-cause and CV mortality.Results2376 deaths occurred among 63,215 patients [68% male, median age 54 (IQR 47–61), CAC 3 (IQR 0–94.3)]. ML2 was similar to ML1 to predict all-cause mortality (Area Under the Curve (AUC) 0.819 vs 0.821, p ?= ?0.23), but superior for CV mortality (0.847 vs 0.845, p ?= ?0.03).Low CAC density increased mortality impact, particularly ≤0.75. Very low CAC density ≤0.75 was present in only 4.3% of the patients with measurable density, and 75% occurred in CAC1-100. The number of diseased vessels did not increase mortality overall when simultaneously accounting for CAC and CAC density.ConclusionCAC density contributes to mortality risk primarily when it is very low ≤0.75, which is primarily observed in CAC 1–100. CAC and CAC density are more important for mortality prediction than the number of diseased vessels, and improve prediction of CV but not all-cause mortality. Explainable ML techniques are useful to describe granular relationships in otherwise opaque prediction models.     

Right ventricular dysfunction by computed tomography associates with outcomes in severe aortic stenosis patients undergoing transcatheter aortic valve replacement

BackgroundAlthough cardiac computed tomography angiography (CCTA) assessment of right ventricular dysfunction (RVD) is feasible, the incremental prognostic value remains uncertain in patients undergoing transcatheter aortic valve replacement (TAVR) evaluation. This study sought to determine the incremental clinical utility of RVD identification by CCTA while accounting for clinical and echocardiographic parameters.MethodsPatients who underwent multiphasic ECG-gated functional CCTA using dual-source system for routine TAVR planning were evaluated. Biphasic contrast protocol injection allowed for biventricular contrast enhancement. CCTA-based RVD was defined as right ventricular ejection fraction (RVEF) ?< ?50%. The association of CCTA-RVD with all-cause mortality and the composite outcome of death or heart failure hospitalization after TAVR was evaluated and examined for its incremental utility beyond clinical risk assessment and echocardiographic parameters.ResultsA total of 502 patients were included (median [IQR] age, 82 [77 to 87] years; 56% men) with a median follow-up of 22 [16 to 32] months. Importantly, 126 (25%) patients were identified as having RVD by CCTA that was not identified by echocardiography. CCTA-defined RVD predicted death and the composite outcome in both univariate analyses (HR for mortality, 2.15; 95% CI, 1.44–3.22; p ?< ?0.001; HR for composite outcome, 2.11; 95% CI, 1.48–3.01; p ?< ?0.001) and in multivariate models that included clinical risk factors and echocardiographic findings (HR for mortality, 1.74; 95% CI, 1.11–2.74; p ?= ?0.02; HR for composite outcome, 1.63; 95% CI, 1.09–2.44; p ?= ?0.02).ConclusionsFunctional CCTA assessment pre-TAVR correctly identified 25% of patients with RVD that was not evident on 2D echocardiography. The presence of RVD on CCTA independently associates with clinical outcomes post-TAVR.