Reproducibility of quantitative coronary computed tomography angiography in asymptomatic individuals and patients with acute chest pain

Cytomegalovirus Antibodies and Coronary Artery Disease in People with HIV: A Cohort Study

People with HIV (PWH) have a high risk of coronary artery disease (CAD). Cytomegalovirus (CMV) co-infection is very common in PWH, but little is known about its association with CAD. We aimed to investigate if CMV IgG serostatus and concentrations are associated with CAD in PWH. From the Copenhagen Comorbidity in HIV Infection (COCOMO) Study we included PWH with coronary CT angiography (CCTA) and quantitative CMV IgG concentration measurements. We measured the stenosis grades and plaque volumes in the coronary vessels. Using multivariable regressions adjusted for traditional CAD risk factors, we investigated if CMV IgG serostatus and concentrations were associated with any atherosclerosis, obstructive CAD, or plaque volumes. We included 620 PWH of whom 586 had positive CMV serostatus, which was not associated with any atherosclerosis, obstructive CAD, or plaque volumes. A doubling of CMV IgG concentrations was associated with any atherosclerosis (OR 1.21 [95% CI: 1.06-1.39]), obstructive CAD (OR 1.31 [95% CI: 1.07-1.59]), and higher total plaque volume (1.56 [95% CI: 1.21-2.01] fold increase), but the association did not remain significant after adjustment for traditional CAD risk factors. This indicates that CMV IgG serostatus and concentrations are not independently associated with prevalent CAD in PWH.

The importance of nonobstructive plaque characteristics in symptomatic and asymptomatic coronary artery disease

BACKGROUND

We examined obstructive and nonobstructive plaque volumes in populations with subclinical and clinically manifested coronary artery disease (CAD) using quantitative computed tomography (QCT).

METHODS

855 participants with CAD (274 asymptomatic individuals, 254 acute chest pain patients without acute coronary syndrome (ACS), and 327 patients with ACS) underwent QCT of proximal coronary segments to assess participant-level plaque volumes of dense calcium, fibrous, fibrofatty, and necrotic core tissue.

RESULTS

Nonobstructive (<50% stenosis) plaque volumes were greater than obstructive plaque volumes, irrespective of population (all p<0.0001): Asymptomatic individuals (mean (95% CI)): 218 [190-250] vs. 16 [12-22] mm3; acute chest pain patients without ACS: 300 [263-341] vs. 51 [41-62] mm3; patients with ACS: 370 [332-412] vs. 159 [139-182] mm3. After multivariable adjustment, nonobstructive fibrous and fibrofatty tissue volumes were greater in acute chest pain patients without ACS compared to asymptomatic individuals (fibrous tissue: 122 [107-139] vs. 175 [155-197] mm3, p<0.01; fibrofatty tissue: 44 [38-50] vs. 71 [63-80] mm3, p<0.01. Necrotic core tissue was greater in ACS patients (29 [26-33] mm3) compared to both asymptomatic individuals (15 [13-18] mm3, p<0.0001) and acute chest pain patients without ACS (21 [18-24] mm3, p<0.05). Nonobstructive dense calcium volumes did not differ between the three populations: 29 [24-36], 29 [23-35], and 41 [34-48] mm3, p>0.3 respectively.

CONCLUSION

Nonobstructive CAD was the predominant contributor to total atherosclerotic plaque volume in both subclinical and clinically manifested CAD. Nonobstructive fibrous, fibrofatty and necrotic core tissue volumes increased with worsening clinical presentation, while nonobstructive dense calcium tissue volumes did not.

Coronary CT Value in Quantitative Assessment of Intermediate Stenosis

Background and Objectives: Cardiac computed tomography angiography (CCTA) is an excellent non-invasive imaging tool to evaluate coronary arteries and exclude coronary artery disease (CAD). Managing intermediate coronary artery stenosis with negative or inconclusive functional tests is still a challenge. A regular stenosis evaluation together with high-risk plaque features, using semi-automated programs, are becoming promising tools. This case–control study was designed to evaluate the intermediate lesion features’ impact on CAD outcomes, using a semi-automated CCTA atherosclerotic plaque analysis program. Materials and Methods: We performed a single-center, prospective cohort study. A total of 133 patients with low to intermediate risk of CAD, older than 18 years with no previous history of CAD and good quality CCTA images were included in the study, and 194 intermediate stenosis (CAD-RADS 3) were analyzed. For more detailed morphological analysis, we used semi-automated CCTA-dedicated software. Enrolled patients were prospectively followed-up for 2 years. Results: Agatston score was significantly higher in the major adverse cardiovascular events (MACE) group (p = 0.025). Obstruction site analysis showed a significantly lower coronary artery remodeling index (RI) among patients with MACE (p = 0.037); nonetheless RI was negative in both groups. Plaque consistency analysis showed significantly bigger necrotic core area in the MACE group (p = 0.049). In addition, unadjusted multivariate analysis confirmed Agatston score and RI as significant MACE predictors. Conclusions: The Agatston score showes the total area of calcium deposits and higher values are linked to MACE. Higher plaque content of necrotic component is also associated with MACE. Additionally, negatively remodeled plaques are linked to MACE and could be a sign of advanced CAD. The Agatston score and RI are significant in risk stratification for the development of MACE.

Reproducibility of quantitative plaque measurement in advanced coronary artery disease

BACKGROUND

The ability to characterize and to quantify the extent of coronary artery disease has the potential to improve the prognostic capability of coronary computed tomography angiography. Although reproducible techniques have been described in those with mild coronary disease, this has yet to be assessed in patients with advanced disease.

METHODS

Twenty patients with known multivessel disease underwent repeated computed tomography coronary angiography, 2 weeks apart. Coronary artery segments were analysed using semi-automated software by two trained observers to determine intraobserver, interobserver and interscan reproducibility.

RESULTS

Overall, 149 coronary arterial segments were analysed. There was excellent intraobserver and interobserver agreement for all plaque volume measurements (Lin's coefficient 0.95 to 1.0). There were no substantial interscan differences (P ​> ​0.05 for all) for total (2063 ​± ​1246 ​mm3, mean of differences -35.6 ​mm3), non-calcified (1795 ​± ​910 ​mm3, mean of differences -4.3 ​mm3), calcified (298 ​± ​425 ​mm3, mean of differences -31.3 ​mm3) and low-attenuation (13 ​± ​13 ​mm3, mean of differences -2.6 ​mm3) plaque volumes. Interscan agreement was highest for total and noncalcified plaque volumes. Calcified and low-attenuation plaque (-236.6 to 174 ​mm3 and -15.8 to 10.5 ​mm3 respectively) had relatively wider 95% limits of agreement reflecting the lower absolute plaque volumes.

CONCLUSION

In the presence of advanced coronary disease, semi-automated plaque quantification provides excellent reproducibility, particularly for total and non-calcified plaque volumes. This approach has major potential to assess change in disease over time and optimize risk stratification in patients with established coronary artery disease.

Sex differences in coronary plaque changes assessed by serial computed tomography angiography

Long-term data on sex-differences in coronary plaque changes over time is lacking in a low-to-intermediate risk population of stable coronary artery disease (CAD). The aim of this study was to evaluate the role of sex on long-term plaque progression and evolution of plaque composition. Furthermore, the influence of menopause on plaque progression and composition was also evaluated. Patients that underwent a coronary computed tomography angiography (CTA) were prospectively included to undergo a follow-up coronary CTA. Total and compositional plaque volumes were normalized using the vessel volume to calculate a percentage atheroma volume (PAV). To investigate the influence of menopause on plaque progression, patients were divided into two groups, under and over 55 years of age. In total, 211 patients were included in this analysis, 146 (69%) men. The mean interscan period between baseline and follow-up coronary CTA was 6.2 ± 1.4 years. Women were older, had higher HDL levels and presented more often with atypical chest pain. Men had 434 plaque sites and women 156. On a per-lesion analysis, women had less fibro-fatty PAV compared to men (β -1.3 ± 0.4%; p < 0.001), with no other significant differences. When stratifying patients by 55 years age threshold, fibro-fatty PAV remained higher in men in both age groups (p < 0.05) whilst women younger than 55 years demonstrated more regression of fibrous (β -0.8 ± 0.3% per year; p = 0.002) and non-calcified PAV (β -0.7 ± 0.3% per year; p = 0.027). In a low-to-intermediate risk population of stable CAD patients, no significant sex differences in total PAV increase over time were observed. Fibro-fatty PAV was lower in women at any age and women under 55 years demonstrated significantly greater reduction in fibrous and non-calcified PAV over time compared to age-matched men. (ClinicalTrials.gov number, NCT04448691.)

Correlation between intracranial vertebral artery stenosis diameter measured by digital subtraction angiography and cross-sectional area measured by optical coherence tomography

Background

Intracranial vertebral artery (V4 segment) stenosis quantification traditionally uses the narrowest stenosis diameter. However, the stenotic V4 lumen is commonly irregularly shaped. Optical coherence tomography (OCT) allows a more precise calculation of V4 geometry. We compared the narrowest diameter stenosis (DS), measured by digital subtraction angiography (DSA), with the area stenosis (AS), measured by OCT. We hypothesized that DS is the gold standard for measuring the degree of stenosis.

Methods

Five neuroradiologists evaluated 49 stenosed V4 segments in a blinded protocol. V4 stenosis was measured in millimeters on DSA at its narrowest diameter. OCT was used to estimate the cross-sectional luminal area. We also used automated software to measure DS. Three different angles (anterior, lateral, and oblique views) were used for calculations, and the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and Warfarin–Aspirin Symptomatic Intracranial Disease (WASID) methods were used in all measurements. Spearman’s R values were calculated. Non-linear regression analysis was performed between the DS and AS, with statistically different correlations.

Results

A high correlation was observed between the WASID and NASCET methods to measure DS with observer measurement and automated software. A good correlation was found between DS measured by observers and AS measured by OCT. Non-linear regression analysis showed that only observer measurement using the oblique view and the WASID method could attain statistically significant differences, but it was weak (r=0.389).

Conclusion

Measurement of the narrowest diameter was not a reliable predictor of the cross-sectional area of V4 stenosis. Larger studies are therefore needed to develop a new evaluation system based on V4 stenosis.

Artificial intelligence approaches to predict coronary stenosis severity using non-invasive fractional flow reserve

Fractional flow reserve is the current reference standard in the assessment of the functional impact of a stenosis in coronary heart disease. In this study, three models of artificial intelligence of varying degrees of complexity were compared to fractional flow reserve measurements. The three models are the multivariate polynomial regression, which is a statistical method used primarily for correlation; the feed-forward neural network; and the long short-term memory, which is a type of recurrent neural network that is suited to modelling sequences. The models were initially trained using a virtual patient database that was generated from a validated one-dimensional physics-based model. The feed-forward neural network performed the best for all test cases considered, which were a single vessel case from a virtual patient database, a multi-vessel network from a virtual patient database, and 25 clinically invasive fractional flow reserve measurements from real patients. The feed-forward neural network model achieved around 99% diagnostic accuracy in both tests involving virtual patients, and a respectable 72% diagnostic accuracy when compared to the invasive fractional flow reserve measurements. The multivariate polynomial regression model performed well in the single vessel case, but struggled on network cases as the variation of input features was much larger. The long short-term memory performed well for the single vessel cases, but tended to have a bias towards a positive fractional flow reserve prediction for the virtual multi-vessel case, and for the patient cases. Overall, the feed-forward neural network shows promise in successfully predicting fractional flow reserve in real patients, and could be a viable option if trained using a large enough data set of real patients.

Coronary plaque composition assessed by cardiac computed tomography using adaptive Hounsfield unit thresholds

PURPOSE

Quantitative computed tomography (QCT) may be useful in detecting high-risk patients with coronary atherosclerosis. Assessment of plaque composition using fixed Hounsfield unit (HU) thresholds is influenced by luminal contrast density. A method using adaptive HU thresholds has therefore been developed. This study investigates agreement between plaque volumes derived using fixed and adaptive HU thresholds and the influence of luminal contrast density on the determination of plaque composition.

METHODS

We performed QCT in 260 patients with recent acute-onset chest pain without acute coronary syndrome. Plaque volumes of necrotic core (NC), fibrous fatty (FF), fibrous (FI) and dense calcium (DC) tissue were measured in 1161 coronary segments. Agreement between plaque volumes using fixed and adaptive HU thresholds was tested using the Bland-Altman method. Additionally, patients were stratified into tertiles of ascending aortic luminal contrast density and plaque volumes were compared.

RESULTS

Bland-Altman plots revealed that fixed HU thresholds underestimated FI and FF plaque volumes and overestimated NC and DC plaque volumes compared to adaptive HU thresholds. Volumes of dense calcium plaque differed with increasing tertiles of luminal contrast density when using fixed HU thresholds but not when using adaptive HU thresholds: DC for fixed HU thresholds (mm³, median (95%CI)): 7.73 (5.17;12.31), 9.83 (6.55;13.57), 12.02 (8.26;16.24); DC for adaptive HU thresholds (mm³, median (95%CI)): 7.34 (5.12;12.03), 7.78 (5.40;12.61), 8.56 (5.22;12.69).

CONCLUSIONS

Plaque volumes by fixed and adaptive HU thresholds differed. Plaque volumes by adaptive HU thresholds were more independent of luminal contrast density for higher attenuation tissues compared to fixed HU thresholds.