Pericoronary adipose tissue attenuation leads to improved prognostication beyond atherosclerotic burden and high-risk plaques in patients with suspected coronary artery disease

Funding Acknowledgements

Type of funding sources: None.

Background

Inflammation is a key component in the atherosclerotic process, initiating and sustaining plaques and serving as a trigger for plaque rupture leading to myocardial infarction. Coronary computed tomography angiography (CCTA) derived pericoronary adipose tissue attenuation (PCATa) has been proposed as surrogate marker for coronary inflammation and might improve risk assessment on top of CCTA derived cardiovascular risk-factors: atherosclerotic burden and plaque vulnerability.

Purpose

To assess the prognostic value of PCATa beyond atherosclerotic burden and high-risk plaques (HRPs).

Methods

A total of 543 patients who underwent CCTA because of suspected CAD were included. CCTA assessment comprised coronary artery calcium score (CACS), presence of obstructive CAD (≥50% stenosis) and HRPs, total plaque volume (TPV), non-calcified plaque volume (NCPV), and PCATa. The endpoint was a composite of death and non-fatal myocardial infarction (MI). Prognostic thresholds were determined for quantitative CCTA variables.

Results

During a median follow-up of 6.6 [interquartile range: 4.7-7.8] years, the endpoint was observed in 42 (20 MI/22 death) patients. CACS >83, obstructive CAD, HRPs, TPV >269mm3, and NCPV >83mm3 were associated with shorter time to the endpoint with unadujsted hazard ratio’s (HR) of 5.37 (95% confidence interval (CI): 2.56-11.29), 5.70 (95% CI: 2.40-13.55), 3.31 (95% CI: 1.80-6.07), 7.76 (95% CI: 3.59-16.81), and 6.77 (95% CI: 3.24-14.16), respectively (p < 0.001 for all). PCATa of the RCA >-74.4 Hounsfield units was associated with worse prognosis (unadjusted HR: 1.99, 95% CI: 1.04-3.79, p = 0.037), whereas PCATa of the LAD and Cx were not associated with prognosis. PCATa of the RCA remained a significant predictor of death and non-fatal MI corrected for CCTA variables and clincal chacteristics associated with the endpoint (adjusted HR: 2.11, 95% CI: 1.11-4.04, p = 0.024).

Conclusion

Coronary inflammation determined by PCATa of the RCA provides incremental prognostic value beyond clinical characteristics and comprehensive CCTA assessment.

Abstract Figure. Take-home figure

Incremental prognostic value of pericoronary adipose tissue attenuation on top of comprehensive CCTA assessment

Background

Coronary computed tomography angiography (CCTA) derived parameters linked to severity and extent of atherosclerosis are associated with prognosis in patients with coronary artery disease (CAD). Furthermore, coronary inflammation, by determining pericoronary adipose tissue CT-attenuation (PCATa), can be assessed on CCTA as well and has been proposed as promising prognostic marker.

Objective

To assess the prognostic value of PCATa on top of traditional CCTA derived atherosclerotic parameters.

Methods

A total of 543 patients who underwent CCTA because of suspected CAD and in whom follow-up was obtained were included. CCTA assessment comprised; coronary artery calcium score (CACS), presence of obstructive CAD (≥50% stenosis) and high-risk plaques (HRP), total plaque volume (TPV), non-calcified plaque volume (NCPV), and PCATa. The endpoint was a composite of death and non-fatal myocardial infarction (MI). Optimal prognostic thresholds were determined for quantitative CCTA variables. Univariable Cox regression analyses were performed to determine clinical characteristics and CCTA variables associated with the endpoint, a subsequent multivariable Cox regression analysis that included variables associated with the endpoint was used to determine independent predictors of the endpoint. An additional Cox regression analysis was performed to test the incremental prognostic value of CCTA variables over clinical characteristics, significance of each sequentially added variable was tested using the likelihood ratio test.

Results

During a median follow-up time of 6.6 [interquartile range: 4.7–7.8] years, a total of 42 (20 MI/22 death) (8%) patients suffered an endpoint. CACS >83.2, obstructive CAD, HRP, TPV >269mm3, and NCPV >83mm3 were all associated with occurrence of the endpoint with unadujsted hazard ratio's (HR) of; 5.37, 5.70, 3.31, 7.76, and 6.77, respectively (p<0.001 for all). PCATa of the RCA above −74.4 Hounsfield units (HU) had a detrimental effect on prognosis (unadjusted HR: 1.99, p=0.037), while PCATa of the LAD nor Cx was associated with outcome (Log-rank p-value 0.255 and 0.218, respectively). PCATa of the RCA remained an independent predictor of death and MI when incorporated in a multivariable analysis inlcuding all CCTA variables and clincal chacteristics associated with the endpoint (adjusted HR: 2.11, p=0.024). Furthermore, adding PCATa of the RCA to a model that included clinical characteristics and all CCTA parameters led to an improvement of the prognostic value of the model (change in Chi-square = 4.45, p=0.035) (figure).

Conclusion

Coronary inflammation of the RCA determined by PCATa provides incremental prognostic value on top of traditional CCTA parameters linked to extent and severity of CAD.

Figure 1. Cox regression analysis demonstrating the incremental prognostic value of sequentially added CCTA variables over clinical characteristics tested for significance using the likelihood ratio test.

Funding Acknowledgement

Type of funding source: None

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