Influence of gender on coronary atherosclerosis and inflammatory biomarker profile: a CT angiographic study

Background and aims

The burden of coronary atherosclerosis differs between men and women. Beyond traditional cardiovascular risk factors, inflammatory biomarkers can influence plaque formation and progression. We analyzed the influence of gender difference on coronary atherosclerosis and inflammatory cytokines.

Methods

Coronary CT-Angiography was performed in 301 patients and plaque morphology was quantitatively and qualitatively assessed using semi-automated software (Autoplaque version 2.5, Cedars-Sinai Medical Center, Los Angeles, CA). We analyzed total (TPV), non-calcified (NCPV), calcified (CPV) and low-density plaque volume in mm3 (LDPV, defined as plaque attenuation <30HU). Serum was analyzed for various cytokines including Interleukin (IL)-1a, IL-1b, IL-2, IL-4, IL-6, IL-7, IL-8, IL-10, IL-13, Il-15, IL-17, TNF-a, IFNg, CRP, MCP-1, MIP-1a, Eotaxin, G_CSF and GM-CSF using Luminex assay.

Results

Out of 301 patients, 94 (31%) were female and 207 (69%) were male. As compared to women, men were significantly younger (62 vs. 57 years, p<0.001) and showed a higher BMI (28 vs. 26 kg/m2, p=0.005). No differences were seen for hypertension, hyperlipidemia, diabetes, smoking habits and family history of CAD. All plaque characteristics showed significant higher values in men as compared to women (all p<0.05). In men, cytokine profile showed significantly lower serum levels for IL-2 (3.20 [3.20; 7.01] vs. 4.31 [3.20; 9.68]; p=0.01) and Interferon-gamma (3.20 [3.20; 14.72] vs. 8.76 [3.20; 26.26]; p<0.001) and significantly higher levels for MCP-1 (224 [117; 327] vs. 155 [49; 260]; p<0.001). In multivariable logistic regression analysis, Interferon-gamma showed significant inverse association to male gender (OR 0.35; 95% CI: 0.17–0.72; p=0.004), but IL-2 and MCP-1 did not. The association of Interferon-gamma to gender was independent of age (OR 0.57; 95% CI: 0.43–0.76; p<0.001) and BMI (OR 2.12; 95% CI 1.25–3.62; p=0.006)

Conclusion

Coronary plaque volume and morphology significantly differs between men and women and so does the inflammatory cytokine profile. Albeit significantly lower coronary plaque burden in women, serum levels of interferon-gamma - a known pro-inflammatory cytokine - was significantly higher in women with independent association to gender. Whether interferon-gamma plays contradicting roles in the process of coronary atherosclerosis in men and women needs to be explored in future studies to identify potential gender-specific targets for therapeutic interventions.

Funding Acknowledgement

Type of funding sources: None.

Independent predictors of major cardiovascular events as quantitatively assessed by coronary CT-angiography: a long-term follow-up analysis

Introduction

Quantitative CT coronary angiography using semi-automated software provides detailed information about plaque volume and high-risk plaque characteristics, beyond traditional measures like diameter stenosis. We assessed the potential value of plaque quantity and morphology to independently predict MACE in a cohort with long-term follow up.

Methods

In this secondary analysis of 301 symptomatic patients undergoing coronary CTA at baseline, total plaque volume (TPV), non-calcified- (NCPV), calcified- (CPV) and vulnerable coronary plaque volume (in mm3), diameter stenosis (in %) and remodeling index were quantified using semi-automated software (Autoplaque version 2.5, Cedars-Sinai Medical Center, Los Angeles, CA). Patients were followed for major cardiovascular events (MACE), defined as a composite of cardiovascular death, myocardial infarction and coronary revascularization. Optimal thresholds for each quantitative CTA measure were computed using CART-algorithm (Classification and Regression Trees).

Results

Complete follow-up was available for 234 (78%) patients. The mean age was 59±10 years. Over a median follow-up of 10.7 years, the composite outcome occurred in 34 (15%) patients (5 patients with cardiovascular death, 6 with myocardial infarction, 26 with revascularization). Patients experiencing MACE had more frequently hypertension (p=0.03) and a higher Framingham risk score (p=0.002). Survival anaylsis using cox proportional hazard ratios showed significant univariate associations between MACE and TPV (HR 5.16; 95% CI 1.58–16.89; p=0.007), NCPV (HR 4.83; 95% CI 1.45–15.81; p=0.009), CPV (HR 2.86; 95% CI 1.39–5.86; p=0.004), vulnerable plaque volume (HR 3.35; 95% CI 1.52–7.41; p=0.003), diameter stenosis (HR 5.19; 95% CI 2.64–10.22; p<0.001) and remodeling index (HR 4.24; 95% CI 2.03–8.86; p<0.001). In multivariable cox regression analysis diameter stenosis (HR 3.70; 95% CI 1.72–7.93; p=0.001) and remodeling index (HR 2.69; 95% CI 1.19–6.09; p=0.018) remained significant independent predictors of MACE, adjusted for Framingham risk score (HR 2.56; 95% CI 1.26–5.22; p=0.010), however plaque volume and plaque subcomponents did not.

Conclusion

On long term follow-up, remodeling index and coronary diameter stenosis obtained by quantitative coronary CT angiography independently predicted MACE on multivariable assessment. More comprehensive plaque assessment algorithms including plaque volume as well as plaque subcomponents were significantly associated with MACE in univariate, but not multivariate analysis after adjustment for diameter stenosis and remodeling index.

Funding Acknowledgement

Type of funding sources: None.

Computed tomography-derived characterisation of pericoronary,epicardial and paracardial adipose tissue and its association with myocardial ischemia as assessed by computed and invasive fractional flow

Introduction

Increased pericoronary adipose tissue (PCAT) computed tomography (CT) attenuation derived from coronary CT angiography (CTA) around the right coronary artery (RCA) reflects coronary inflammation and relates to cardiac mortality.

Purpose

We aimed to investigate the yet unclear association between CT-derived characterisation of different cardiac adipose tissue compartments and the presence of myocardial ischemia as assessed by fractional flow reserve (FFR).

Methods

133 stable individuals (64 years, 74% male) with coronary artery disease (CAD) underwent CTA including computed FFR (FFR-CT) measurement followed by invasive angiography with FFR (invasive FFR) assessment. The CT attenuation (HU) and volume (mm3) of PCAT were quantified around the RCA (10 to 50 mm from RCA ostium), the proximal 40 mm of the left anterior descending artery (LAD) and the circumflex artery (LCX) with the help of semi-automated software. The per patient PCAT CT attenuation was calculated as followed: (PCAT CT attenuation of RCA+LAD+LCX)/3. Quantification of epicardial adipose tissue (EAT) and paracardial adipose tissue (PAT; all intrathoracic adipose tissue outside the pericardium) were performed in non-contrast cardiac CT data sets using a fully automated deep-learning based algorithm.

Results

Median FFR-CT was 0.86 [0.79, 0.91] and median invasive FFR was 0.87 [0.81, 0.93]. Patients with presence of myocardial ischemia (n=26) defined by a FFR-CT threshold of ≤0.75 showed a significant higher PCAT CT attenuation of RCA (−75.1 HU vs. −81.1 HU, p=0.011) and per patient (−74.5 HU vs. −77.7 HU, p=0.045) than individuals without myocardial ischemia (n=107). In multivariable analysis adjusted for age, BMI, gender and traditional risk factors, both RCA and per patient PCAT CT attenuation were significant predictors of myocardial ischemia as assessed by FFRCT ≤0.75. Between individuals with myocardial ischemia compared to individuals without myocardial ischemia there was no significant difference neither in the volume and CT attenuation of EAT and PAT nor in the PCAT volume of RCA, LAD, LCX and per patient PCAT volume.

Conclusions

Our observations suggest that PCAT CT attenuation instead of PCAT volume, EAT and PAT measures might be associated with the presence of myocardial ischemia as assessed by FFR.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): German Heart Foundation e.V.

CT-derived characterization of pericoronary, paracardial and epicardial adipose tissue and its association with myocardial ischemia as assessed by adenosine stress CMR perfusion imaging

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): German Heart Foundation e.V.

Introduction

 Increased attenuation of pericoronary adipose tissue (PCAT) around the right coronary artery (RCA) is a new imaging biomarker to detect coronary inflammation derived from routine coronary CT angiography (CTA) and has been shown to be associated with cardiac mortality. Increased volume of epicardial adipose tissue (EAT) has been reported be associated with myocardial ischemia.

Purpose

 We aimed to investigate a potential association between CTA-derived PCAT measures and myocardial ischemia as assessed by adenosine stress CMR perfusion imaging. 

Methods

In this single-centre study 109 stable individuals (mean age of 62 ± 11 years, 77% males) with coronary artery disease underwent CTA followed by adenosine stress CMR perfusion imaging to detect myocardial ischemia. PCAT CT attenuation (HU) and PCAT volume (cm3) was measured around the RCA (10 to 50 mm from RCA ostium), the proximal 40 mm of the left anterior descending artery (LAD) and the circumflex artery (LCX) using semi-automated software. Per patient PCAT CT attenuation was calculated as followed: (PCAT attenuation of RCA + LAD + LCX)/3). Non-contrast CT data sets were used for coronary calcium scoring and the quantification of EAT (located between the myocardial surface and the pericardium) and paracardial adipose tissue (PAT; intrathoracic and outside of the pericardium). 

Results

 Between patients with evidence of significant myocardial ischemia as assessed by adenosine stress CMR perfusion imaging (n = 35) and patients without myocardial ischemia (n = 74) there was no significant difference in the CT attenuation of RCA (-85.3 HU vs. -85.7  HU, p = 0.87), LAD (-84.8 HU vs. -85.7 HU, p = 0.66) and LCX (-82.8 HU vs. -83.2 HU, p = 0.79) as well as in the per patient PCAT CT attenuation (-84.2 HU vs. -84.9 HU, p = 0.76). Neither did patients with myocardial ischemia within the RCA territory show increased RCA PCAT CT attenuation (-87.7 HU vs. -85.3 HU, p = 0.40); nor was such a relationship found for the territory of the LAD (-80.6 HU vs.  85.8 HU, p = 0.11) or LCX (-83.1 HU vs. -83.0 HU, p = 0.99). The CT attenuation of EAT (-77.9 vs. -78.7 HU, p = 0.65) and PAT (-89.9 HU vs. -90.0 HU, p = 0.93) did not differ between patients with myocardial ischemia compared to patients without myocardial ischemia. Between patients with myocardial ischemia and patients without myocardial ischemia there was no significant difference in the volumes of EAT (118.1 cm3 vs. 110.6 cm3, p = 0.55), PAT (279.5 cm3 vs. 240.9 cm3, p = 0.20) and the per patient PCAT volume (1021.9 mm3 vs. 1015.5 mm3, p = 0.90). In logistic regression analysis the volume and CT attenuation of the different intrathoracic fat compartments PCAT, EAT and PAT were not independently associated with the presence of myocardial ischemia (n.s.). 

Conclusions

  In this single-centre study CTA-derived quantified CT attenuation and volume of PCAT, EAT and PAT were not associated with myocardial ischemia as assessed by adenosine stress CMR perfusion imaging.

Pericoronary adipose tissue attenuation in low-risk asymptomatic individuals, sex-differences and association with markers of cardiovascular disease

Funding Acknowledgements

Type of funding sources: None.

Introduction

Pericoronary adipose tissue (PCAT) attenuation by coronary computed tomography angiography (CCTA) is a marker of coronary inflammation and predicts clinical outcomes in symptomatic patients undergoing CCTA. Sex-differences in PCAT CT attenuation among asymptomatic individuals are not previously described.

Purpose

To evaluate PCAT CT attenuation according to sex and markers of cardiovascular disease (CVD).

Methods

Cross-sectional cohort study including asymptomatic individuals, 50- or 60-year of age, not taking any medicine and without known CVD or type-2 diabetes. At baseline and 5-year follow-up smoking habits, blood pressures and biochemistry (lipids, CRP, fibrinogen, D-dimer, t-PA, PAI-1, vWF) were recorded and Agatston Score measured. At follow-up, CCTA was achieved. Quantitative coronary plaque analysis was performed and PCAT CT attenuation within a radial distance of 3 mm from the outer vessel wall 10–50 mm distal to the origin of the right coronary artery measured. A validated PCAT CT attenuation threshold (high vs low risk) of -70.1 Hounsfield units was applied.

Results

Included were 123 participants (60 women). Independent of co-variation, PCAT CT attenuation (median, [IQR]) was lower in women (-71.0, [-77.2- -67.0]) vs men (-64.5, [-69.9- -57.4]), p < 0.001. No associations between PCAT CT attenuation (high vs low) and risk factors of CVD, CAC or coronary plaque volumes were demonstrated (Table). Variations in blood pressures, biochemical markers and CAC over five years were not associated with PCAT CT attenuation.

Conclusion

In low-risk asymptomatic individuals, PCAT CT attenuation was lower in women compared to men, irrespective of markers of CVD.

Table. Patient characteristics stratified by PCAT CT attenuation PCAT CT attenuation ≤ -70.1 HU (n = 49) PCAT CT attenuation > -70.1 HU (n = 74) p-value Risk factors Age65-years55-years 2623 3143 0.32 SexMenWomen 1534 4826 <0.001 TobaccoNeverCurrent/previous 1732 3737 0.10 Systolic BP, mmHgDiastolic BP, mmHgTotal cholesterol, mmol/lLDL-cholesterol, mmol/lHDL-cholesterol, mmol/lTriglycerides, mmol/l 137 (17)76 (10)5.61 (0.92)3.50 (0.93)1.41 (0.30)1.65 (0.99 - 2.22) 136 (16)77 (10)5.42 (0.82)3.30 (0.82)1.45 (0.35)1.35 (1.03 - 2.11) 0.660.590.230.220.570.52 Biochemistry CRP, mg/lFibrinogen, μmol/lD-dimer, mg/lvWFt-PAPAI-1 1.16 (0.99 - 2.22)9.5 (8.5 - 10.7)0.40 (0.30 - 0.49)128 (102 - 154)7.1 (5.8 - 8.8)20.5 (16.2 - 31.8) 0.61 (0.30 - 1.14)9.0 (7.8 - 10.0)0.32 (0.24 - 0.47)116 (92 - 146)6.3 (5.1 - 8.8)20.3 (14.7 - 26.3) <0.010.10<0.050.110.200.34 Coronary plaque data Agatston ScoreTotal plaque volume, mm³NCP volume, mm³CP volume, mm³LD-NCP volume, mm³ 1 (0 - 36)15.7 (0 - 143.3)0 (0 - 128.1)0 (0 - 14.6)0.5 (0 - 18.7) 8 (0 - 115)15.6 (0 - 268.2)13.5 (0 - 220.5)1.7 (0 - 31.7)1.8 (0 - 21.8) 0.300.450.490.360.74 Values are n (%), mean (SD) or median (IQR).Abbreviations: HU =Hounsfield unit; LDL =low-density lipoprotein; HDL =high-density lipoprotein; BP =blood pressure; CRP = c-reactive protein: vWF =von-Willebrand Factor; t-PA =tissue plasminogen activator; PAI-1 =plasminogen activator inhibitor -1; NCP =non-calcified plaque; CP =calcified plaque; LD-NCP =low-density non-calcified plaque.

Resolution of leaflet thrombosis under anticoagulant therapy in patients after transcatheter aortic valve implantation: influence of prosthesis type and size

Introduction

Leaflet thrombosis can frequently be identified by computed tomography angiography (CTA) in patients after transcatheter aortic valve implantation (TAVI). Oral anticoagulation is assumed to lead to resolution of thrombosis. We analyzed the resolution of leaflet thrombosis after TAVI by anticoagulant therapy in serial CTA and assessed the influence of prosthesis type.

Methods

Consecutive TAVI patients who underwent CTA follow-up were screened and individuals with leaflet thrombosis on CTA (defined by the presence of hypo-attenuated leaflet thickening, HALT) in whom oral anticoagulation was initiated and who underwent follow-up CTA were included. The type of anticoagulation was according to physicians' discretion. We assessed the resolution of HALT and compared patients with and without resolution of HALT regarding prosthesis type, prosthesis diameter and type of anticoagulation.

Results

Out of 395 patients screened for participation, 36 patients (mean age 80±7, 67% men) with leaflet thrombosis underwent follow-up CTA at a medial interval of 3 months (IQR: 3; 5.75 months) after anticoagulation was initiated. 36 patients received either vitamin-K antagonists (n=28, 78%) or Factor-Xa Inhibitors (n=8, 22%). A total of 22 (61%) balloon-expandable and 14 (39%) self-expandable transcatheter aortic valves were implanted. Nominal prosthesis diameter was 23, 25, 26, 27 and 29 mm in 7 (19%), 1 (3%), 10 (28%), 7 (19%) and 11 (31%) patients, respectively. 30 patients (83%) with anticoagulation showed resolution of HALT, whereas persistent HALT was detected in 6 patients (17%), of whom 1 patient with balloon-expandable and 5 patients with self-expandable valve. No difference was seen in duration of anticoagulation between patients with and without resolution of HALT (p=0.984). In univariate analysis, prosthesis type (balloon-expandable vs. self-expandable valves) showed a significant association of self-expandable valves with lack of resolution of leaflet thrombosis (p=0.017). In multivariable logistic regression analysis, this association persisted (p=0.043) and was independent of the type of anticoagulation (p=0.660) and prosthesis diameter (p=0.942).

Conclusion

Persisting leaflet thrombosis despite anticoagulation is not infrequent and seems to be associated with prosthesis-type rather than small valve diameter or type of anticoagulation. Further research is necessary to identify structural aortic valve determinants for this finding.

Funding Acknowledgement

Type of funding source: None

The association of pericoronary adipose tissue attenuation with major adverse cardiac events (MACE) and atherosclerosis-relevant inflammatory mediators

Background

Increased attenuation of pericoronary adipose tissue (PCAT) around the right coronary artery (RCA) is a new imaging biomarker to detect coronary inflammation derived from routine coronary CT angiography (CTA).

Purpose

We aimed to investigate a potential association between RCA PCAT attenuation and i) serum levels of atherosclerosis-relevant cytokines, ii) different grades of coronary calcification iii) future coronary revascularization within the same coronary artery and iV) MACE (defined by revascularization, myocardial infarction (MI) and/or cardiac death).

Methods

In 293 stable individuals (59.0±9.8 years, 69% males) with intermediate likelihood for coronary artery disease (CAD) blood was drawn and subsequently analyzed for different atherosclerosis-relevant cytokines interleukin (IL)-2, IL- 4, IL-6, IL-7, IL-8, IL-10, IL-13, Il-15, IL-17, TNF-a, IP-10, CRP, MCP-1, MIP-1a, Eotaxin and GM-CSF, followed by coronary calcium scoring (CCS) in non-contrast CT followed by CTA. PCAT CT attenuation (HU) was measured around the RCA (10 to 50 mm from RCA ostium) and the proximal 40 mm of the left anterior descending artery (LAD) and the circumflex artery (LCX) using semi-automated software. Increased RCA PCAT attenuation was defined as PCAT attenuation above the highest quartile (>−73.5 HU). A long-term follow-up over 9.6 years was performed.

Results

PCAT attenuation was similar in different grades of coronary calcification (CAC=0,-80.3 HU; CAC 1–99, −79.2 HU; CAC 100–400, −79.5 HU; CAC >400, −81.0 HU; p>0.05). Adipocytokine MCP-1 (r=0.23, p<0.01) and pro-inflammatory mediator IL-7 (r=0.12, p=0.04) correlated positively with RCA PCAT attenuation, whereas anti-inflammatory mediators Il-4, -10 and -13 correlated inversely (each r<−0.12, each p<0.05). In patients with increased RCA PCAT attenuation the serum levels of MCP-1 were increased (2.37 vs. 2.20, p<0.01), whereas anti-inflammatory mediators IL-4 and -13 were reduced (each p<0.05). 40 patients experienced MACE during follow-up. In multivariable Cox regression analysis, when adjusted by age, gender, baseline medications, obstructive coronary stenosis and CCS, the highest quartiles of PCAT attenuation are an independent predictor of MACE (HR 7.9, p=0.035). In patients with percutaneous coronary intervention (PCI) of the RCA during follow-up, RCA PCAT attenuation was increased at baseline CTA (−73.1 vs −80.2 HU, p=0.008). In patients with PCI of the LAD or LCX during follow-up, PCAT attenuation of LAD and LCX were not increased at baseline CTA (p>0.05).

Conclusions

The information captured by PCAT attenuation is independent of coronary calcification and showed a trend towards a weak association with serum levels of atherosclerosis-relevant inflammatory biomarkers. Increased RCA PCAT attenuation is an independent predictor of MACE and could guide future prevention strategies in stable patients.

Funding Acknowledgement

Type of funding source: None

Influence of lesion location on the accuracy of CT derived FFR: head-to-head comparison with invasive FFR

Background

The accuracy of CT-derived FFR (FFRCT) has been repeatedly reported. However, the influence of lesion location on accuracy is unknown. Therefore, we evaluated the diagnostic accuracy of FFRCT to detect lesion-specific ischemia and determined the influence of lesion location (proximal vs. distal vessel segments) compared to invasively measured FFR in patients with suspected CAD.

Methods

A total of 136 vessels in which “Dual-Source”-CT coronary angiography had been performed due to suspected CAD and who were further referred for invasive coronary angiography with invasive FFR measurement within three months of the index CT examination were retrospectively identified and screened for inclusion in this analysis. Patients with either left main coronary artery stenoses, bifurcation or ostial stenoses were excluded. Invasive FFR was measured using a pressure wire (CERTUS®, St. Jude Medical, Minnesota, USA or Verrata®, Volcano, San Diego, USA). FFRCT was calculated using an on-site prototype (cFFR Version 3.0, Siemens Healthineers, Forchheim, Germany). All vessels were analyzed by an experienced observer blinded to the results of invasive FFR. Stenoses with invasively measured FFR ≤0.80 were classified as hemodynamically significant. We evaluated the diagnostic accuracy of FFRCT in proximal vs. non-proximal vessel segments. Proximal lesions included stenoses located in segment one, six, eleven and twelve. All other stenoses were categorized as distal lesions.

Results

Out of 136 coronary stenoses, 47 (35%) were located in proximal segments and 89 (65%) lesions were located in distal segments. Compared to invasive FFR, the sensitivity of FFRCT to correctly identify/exclude hemodynamically significant stenoses in proximal vessel segments was 93% (95% CI: 68–99.8%) and the specificity was 100% (95% CI: 89–100%), compared to a sensitivity of 72% (95% CI: 46.5–90%) and a specificity of 87% (95% CI: 77–94%) for FFRCT in distal lesions. The positive predictive value was 100% and the negative predictive value was 97% (95% CI: 82.8–99.5%) compared to a positive predictive value of 59% (95% CI: 42–93.9%) and a negative predictive value of 93% (95% CI: 85.4–96.3%) for proximal vs. distal vessel segment, respectively. This corresponds to an accuracy of 98% vs. 84%, respectively (p=0.02). ROC-Curve analysis showed a slightly higher – albeit non-significant – area under the curve for FFRCT to detect hemodynamic relevance in proximal lesions compared to distal lesions (AUC 0.95, p<0.001 vs. AUC: 0.86, p<0.001, respectively, p=0.2).

Conclusion

FFRCT obtained using an on-site prototype shows overall a high diagnostic accuracy for detecting lesions causing ischemia as compared to invasive FFR with a trend towards better diagnostic performance in proximal vessel segments.

Funding Acknowledgement

Type of funding source: None

P3376Software-based automated CT analysis for planning TAVI-Procedures: Systematic validation against expert and novice human interpretation

Introduction

Cardiac computed tomography (CT) is an established modality for planning TAVI procedures.

We validated CT parameters measured by automated software analysis and by newly trained readers against expert readers.

Methods

Consecutive patients with symptomatic severe aortic valve stenosis referred for CT assessment of the aortic root prior to TAVI were included in this analysis. Measurements were performed manually by an expert reader, a newly trained reader as well as semi-automatically using a commercially available workstation. Manual measurements were performed as per clinical standard. For semi-automatic analysis, CT data sets were exported to a dedicated workstation with fully automated detection of the aortic annulus plane.

Results

Out of 159 consecutive patients, 146 patients were included in this analysis (83+10 years). The median annulus area for expert reader, newly trained reader and software measurement was 468 mm2, 511 mm2 and 513 mm2, respectively (p=0.28) whereas the mean annulus diameter showed a mean±SD of 25.6±2 mm, 25.5±2 mm and 25.6±2 mm, respectively, p=0.47. Agreement between expert and newly trained reader for annulus area was good with Bland-Altman analysis showing a systematic overestimation of the annulus area for the newly trained reader of 16 mm2 (95% limits of agreement 42 to −74 mm2) and for automatic software of 20 mm2 (95% limits of agreement 60 to −99 mm2). Assuming an annulus area-based recommendation for a balloon-expandable Sapien 3 prosthesis (23, 26 or 29 mm prosthesis), kappa statistics revealed moderate agreement between expert measurement, newly trained reader and software measurement (κ 0.60 for newly trained reader, κ 0.58 for software measurement, p<0.0001 for all). The time needed for annulus adjustment measurement for the newly trained reader compared to software measurement was 2±0.6 minutes vs. 1±0.5 minutes, respectively, p<0.0001). The software correctly identified the annulus plane without reader correction in 49% of cases and in 51% of cases manual correction of the cusp insertion point or annular tracing had to be performed. Agreement between expert predicted angulation and software predicted angulation was excellent in 55%, good in 29% vs. 31%, moderate in 11% vs. 6% and fair in 5% vs. 8% for LAO/RAO orientation, CAU/CRA orientation, respectively (assuming excellent agreement when difference: <5°, good agreement: 5–10°, moderate agreement: 10–15° and fair agreement: >15°).

Conclusion

Novice human interpretation manually and with semi-automatic assessment of the aortic root for planning TAVI procedures is feasible with good agreement with expert measurement for annulus dimensions and prediction of implantation angles, however with a trend for systematic overestimation of the annulus area. For semi-automatic assessment, reader correction of cusp insertion point and annular dimensions have to corrected for in 50% of cases

5963Automated quantification of epicardial adipose tissue from non-contrast CT on multi-center and multi-vendor data using deep learning

Background

Epicardial adipose tissue (EAT), a metabolically active visceral fat depot surrounding the coronary arteries, has been shown to promote the development of atherosclerosis in underlying coronary vasculature.

Purpose

We evaluate the performance of deep learning (DL), a sub-group of machine learning algorithms, for robust and fully automated quantification of EAT on multi-center cardiac CT data.

Methods

In this study, 850 non-contrast calcium scoring CT scans, from multiple cohorts, scanners and protocols, with manual measurements of EAT from 3 different readers were considered. The DL method was based on a convolutional neural network trained to reproduce the expert measurement. DL global performance was first assessed using all the scans, and then compared to inter-observer variability on a subset of 141 scans. Finally, automated EAT progression was compared to manual measurement using baseline and follow-up serial scans available for 70 subjects. The proposed model was validated using 10-fold cross validation.

Results

Automated quantification was performed in 1.57±0.49 seconds compared to 15 minutes for manual measurement. DL provided high agreement with expert manual quantification for all scans (R=0.974, p<0.001) with no significant bias (0.53 cm3, p=0.13). EAT volume was higher in patients with hypertension (+18.02 cm3, p<0.001, N=442), with diabetes (+18.33 cm3, p<0.001, N=75) and with hypercholesterolemia (+7.33 cm3, p=0.039, N=508). Manual EAT volumes measured by two experienced readers on 141 scans were highly correlated (R=0.984, p<0.001) but presented a significant difference of 4.35 cm3 (p<0.001). On these 141 scans, DL quantifications were highly correlated to both experts' measurements (R=0.973, p<0.001; R=0.979, p<0.001) with significant and non-significant bias for readers 1 and 2 (5.19 cm3, p<0.001; 0.84 cm3, p=0.26), respectively. In 70 subjects, EAT progression quantified by DL correlated strongly with EAT progression measured by the expert reader (R=0.905, p<0.001) with no significant bias (0.64 cm3, p=0.43), and was related to increased non-calcified plaque burden quantified from coronary CT angiography (5.7% vs 1.8%, p=0.026).

Automated vs. manual EAT volume

Conclusion

Deep learning allows rapid, robust and fully automated quantification of EAT from calcium scoring CT. It performs as an expert reader and can be implemented for routine cardiovascular risk assessment.

Acknowledgement/Funding

1R01HL133616/01EX1012B/Adelson Medical Research Foundation

P6151Fully automated epicardial adipose tissue volume and density measured from non-contrast CT predict major adverse cardiovascular events in asymptomatic subjects

Background

Epicardial adipose tissue (EAT) volume and density has shown to correlate with standard markers of coronary artery disease (CAD) and may predict major adverse cardiovascular events (MACE).

Purpose

We aimed to evaluate the prognostic value of EAT volume and density measured by fully automated deep-learning software from non-contrast cardiac computed tomography (CT).

Methods

We assessed 2071 consecutive asymptomatic subjects (age 56±9 years, 59% male) from the EISNER (Early Identification of Subclinical Atherosclerosis by Noninvasive Imaging Research) trial with long-term follow-up after coronary artery calcium (CAC) measurement. EAT volume and mean density were quantified using automated deep-learning software from non-contrast cardiac CT. MACE was defined as myocardial infarction (MI), cardiac death, late (>90 days) revascularization and acute coronary syndrome (ACS). EAT volume and density were systematically compared to CAC score and atherosclerotic cardiovascular disease (ASCVD) risk score using Cox proportional hazards regression for MACE prediction.

Results

At 14±3 years, 217 subjects suffered MACE. In age-and-gender-adjusted multivariate analysis, ASCVD risk score, CAC (two-fold increase) and EAT volume (two-fold increase) were associated with increased risk of suffering MACE [Hazard Ratio (HR) (95% CI): 1.03 (1.01–1.04); 1.25 (1.19–1.30); and 1.36 (1.08–1.70) respectively, p<0.01 for all] (Figure); the corresponding Harrell's C-statistic was 0.76. The area-under-the curve from receiver-operator characteristic analysis for MACE prediction increased significantly from 0.69 to 0.77 (p<0.0001) when EAT volume and CAC were added to the current clinical standard (ASCVD, family history and obesity measures BMI and BSA). Both in men and women, increase in EAT volume was associated with increased risk of MACE, with HR 1.14 (1.06–1.22), p<0.001 in men vs. 1.15 (1.01–1.31), p=0.03 in women, for each 20 cubic centimeter increase in volume. EAT density (HU) was independently inversely associated with MACE [HR: 0.96 (0.93–0.99), p=0.01].

MACE Prediction

Conclusions

EAT volume and density measurements improve prediction of MACE in asymptomatic populations over the current clinical standard. Fully automated EAT volume and density quantification by deep-learning from non-contrast cardiac CT can provide additional prognostic value for the asymptomatic patient.

Acknowledgement/Funding

1R01HL133616, Forschungsstiftung Medizin Universitätsklinikum Erlangen, grant from Dr Miriam and Sheldon G. Adelson Medical Research Foundation

P6164High level of EPA is associated with lower perivascular coronary attenuation as measured by coronary CTA

Introduction

Pericoronary adipose tissue (PCAT) composition has been recently shown to be a potential novel marker of coronary inflammation with higher PCAT attenuation shown to indicate increased cardiac mortality. Polyunsaturated fatty acids (PUFAs), especially Omega-3 fatty acids (n3), are thought to alter inflammatory response and intake of high dose Eicosapentaenoic acid (EPA, C20_5 n3) was shown to decrease mortality, however exact pathophysiological mechanisms are unclear. Therefore, we sought to determine whether blood levels of PUFAs are associated with differences in pericoronary fat attenuation.

Methods

In 64 symptomatic patients with intermediate pretest-likelihood for coronary artery disease presenting with atypical angina, coronary CTA was performed. PCAT attenuation was measured in Hounsfield Units (HU) around the proximal 40mm of the right coronary artery (RCA) using semi-automated software. Erythrocyte membrane fatty acid composition (in percentage) was analyzed with a standardized analytical methodology, displaying a variety of fatty acids including n-3 fatty acids using gas chromatography.

Results

Patients were divided into two groups (each n=32) using the median PCAT attenuation of −78.1 Hounsfield units (HU), resulting in one group with low (−95.58 to −78.17 HU) and one with high (−78.06 to −62.92 HU) PCAT attenuation. Among both groups, no differences were seen in age, sex, BMI, traditional cardiovascular risk factors or the number of cardiovascular risk factors (all p>0.05). In univariate analysis, significantly higher values of EPA (1.00% [0.78; 1.26] vs. 0.78% [0.63; 0.99]; p=0.02) were seen in patients with lower PCAT attenuation. All other fatty acids showed no significant differences (all p>0.05). Moreover, a significant negative correlation was seen between PCAT attenuation and EPA (Pearson correlation coefficient −0.38; p=0.002), but not for age, sex, BMI or number of cardiovascular risk factors (all p>0.1). Multivariable linear regression analysis confirmed this association and showed a significant inverse association of EPA to PCAT attenuation (β=−0.31, p=0.017), independent of age, gender, BMI and number of CV risk factors (all p>0.1).

Conclusion

High levels of EPA are associated with lower PCAT attenuation on coronary CTA indicating different composition of pericoronary adipose tissue potentially caused by a lesser degree of coronary inflammation.

30Machine learning to predict the long-term risk of myocardial infarction and cardiac death based on clinical risk, coronary calcium and epicardial adipose tissue: a prospective study

Background/Introduction

Machine learning (ML) allows objective integration of clinical and imaging data for the prediction of events. ML prediction of cardiovascular events in asymptomatic subjects over long-term follow-up, utilizing quantitative CT measures of coronary artery calcium (CAC) and epicardial adipose tissue (EAT) have not yet been evaluated.

Purpose

To analyze the ability of machine learning to integrate clinical parameters with coronary calcium and EAT quantification in order to improve prediction of myocardial infarction (MI) and cardiac death in asymptomatic subjects.

Methods

We assessed 2071 consecutive subjects [1230 (59%) male, age: 56.049.03] from the EISNER (Early Identification of Subclinical Atherosclerosis by Noninvasive Imaging Research) trial with long-term follow-up after non-enhanced cardiac CT. CAC (Agatston) score, age-and-gender-adjusted CAC percentile, and aortic calcium scores were obtained. EAT volume and density were quantified using a fully automated deep learning method. Extreme gradient boosting, a ML algorithm, was trained using demographic variables, plasma lipid panel measurements, risk factors as well as CAC, aortic calcium and EAT measures from CAC CT scans. ML was validated using 10-fold cross validation; event prediction was evaluated using area-under-receiver operating characteristic curve (AUC) analysis and Cox proportional hazards regression. Optimal ML cut-point for risk of MI and cardiac death was determined by highest Youden's index (sensitivity + specificity – 1).

Results

At 152 years' follow-up, 76 events of MI and/or cardiac death had occurred. ML obtained a significantly higher AUC than the ASCVD risk and CAC score in predicting events (ML: 0.81; ASCVD: 0.76, p<0.05; CAC: 0.75, p<0.01, Figure A). ML performance was mostly driven by age, ASCVD risk and calcium as shown by the variable importance (Figure B); however, all variables with non-zero gain contributed to the ML performance. ML achieved a sensitivity and specificity of 77.6% and 73.5%, respectively. For an equal specificity, ASCVD and CAC scores obtained a sensitivity of 61.8% and 67.1%, respectively. High ML risk was associated with a high risk of suffering an event by Cox regression (HR: 9.25 [95% CI: 5.39–15.87], p<0.001; survival curves in Figure C). The relationships persisted when adjusted for age, gender, CAC, CAC percentile, aortic calcium score, and ASCVD risk score; with a hazard ratio of 3.42 for high ML risk (HR: 3.42 [95% CI: 1.54–7.57], p=0.002).

Conclusion(s)

Machine learning used to integrate clinical and quantitative imaging-based variables significantly improves prediction of MI and cardiac death in asymptomatic subjects undergoing CAC assessment, compared to standard risk assessment methods.

Acknowledgement/Funding

NHLBI 1R01HL13361, Bundesministerium für Bildung und Forschung (01EX1012B), Dr. Miriam and Sheldon G. Adelson Medical Research Foundation