Predictive factors of thoracic aortic calcification in patients candidate for cardiac surgery

BACKGROUND

The presence of the severe thoracic aortic calcification (TAC) in cardiac surgery patients is associated with adverse post-operative outcome. However, the relationship between cardiovascular risk factors and aortic plaque burden remains unknown. The objective of this study was to determine the predictive factors of TAC in patients candidate for cardiac surgery.

METHODS

Patients who underwent thoracic CT scan prior to cardiac surgery between August 2020 to April 2021 were included. Of 556 patients, 209 (36.7%) had a thoracic aortic calcium score (TACS) ≥ 400 mm [3] and were compare with the remaining patients. Predictors of severe TAC were assessed through stepwise multivariable logistic regression analysis.

RESULTS

The patients with TACS ≥ 400 had a higher mean age (67.3 ± 7.1 vs. 55.7 ± 10.6; p < 0.001) with a higher frequency of diabetes mellitus (40.7% vs. 30.8%; p = 0.018), dyslipidemia (49.8% vs. 38.6%; p = 0.010), hypertension (60.8% vs. 44.7%; p < 0.001), opium addiction (18.2% vs. 11.2%; p = 0.023), peripheral vascular disease (PVD) (7.7% vs. 2.3%; p = 0.005) as compared with TACS < 400. The multiple determinants of TAC were PVD (OR = 2.86) followed by opium addiction, diabetes and age.

CONCLUSIONS

Thoracic CT scan prior to cardiac surgery for patients with older age, diabetes, opium addiction and PVD is recommended. Our study could serve as a foundation for future research endeavors aimed at establishing a risk score for TAC.

Implication of thoracic aortic calcification over coronary calcium score regarding the 2018 ACC/AHA Multisociety cholesterol guideline: results from the CAC Consortium

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TAC in segments of the ascending and descending thoracic aorta can be assessed by routine CAC scanning.

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TAC assessment with the threshold of 300 improved risk prediction and reclassification for CVD mortality when added to the ASCVD risk score and CAC.

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TAC >300 may improve patient selection for those who would benefit more strongly from statin use, from intermediate ASCVD risk patients who should consider a statin (CAC=1-100), and those where a statin is not recommended (CAC=0).

Objective

TAC is associated with an increased atherosclerotic cardiovascular disease (ASCVD) risk, but it is unclear how to interpret thoracic aortic calcification (TAC) findings in conjunction with ASCVD risk and coronary artery calcium (CAC) score according to 2018 ACC/AHA Multisociety cholesterol guidelines. We evaluate the incremental value of thoracic aortic calcification TAC over CAC for predicting and reclassifying ASCVD mortality risk.

Method

The study included 30,630 asymptomatic individuals (mean age: 55 ± 8 years, male: 64%) from the CAC Consortium. TAC was categorized as TAC 0, 1-300, and >300. Patients were categorized as low (<5%), borderline (5–7.5%), intermediate (7.5–20%), or high (≥20%) 10-year ASCVD risk according to the Pooled Cohorts Equation. In the intermediate risk group, the utility of TAC beyond CAC for statin eligibility was assessed according to the guideline. CAC was categorized as CAC=0 (no statin), CAC 1-100 (favors statin), or CAC>100 (initiate stain).

Results

During the median 11.2 years (IQR 9.2–12.4) follow-up, 345 (1.1%) CVD deaths occurred. TAC>300 was associated with increased CVD mortality after adjusting for ASCVD risk and CAC (HR:4.72, 95% CI: 3.39–6.57, p<0.001). In borderline and intermediate risk groups, TAC improved discrimination when added to a model included ASCVD risk and CAC (C-statistic: 0.77 vs. 0.68 in borderline group; 0.67 vs. 0.63 in intermediate group, both p < 0.05). The addition of TAC over CAC improved risk reclassification in borderline, intermediate and high-risk groups (categorical net reclassification index: 0.40, 0.29, and 0.49, respectively, all p < 0.001). Of intermediate risk participants for whom consideration of CAC was recommended based on the guideline, TAC >300 was associated with an increased CVD mortality risk across each statin eligibility group (all p < 0.001, compared to TAC 0).

Conclusion

TAC was independently associated with CVD death. Among individuals with borderline or intermediate ASCVD risk, a TAC threshold of 300 may provide added prognostic and reclassification value beyond the current guideline-based approach.

Cardiovascular magnetic resonance for the detection of descending thoracic aorta calcification in patients with end-stage renal disease

BACKGROUND

Vascular calcification is an independent predictor of cardiovascular disease in patients with chronic kidney disease. Computed tomography (CT) is the gold-standard for detecting vascular calcification. Radial volumetric-interpolated breath-hold examination (radial-VIBE), a free-breathing gradient-echo cardiovascular magnetic resonance (CMR) sequence, has advantages over CT as it is ionising radiation-free. However, its capability in detecting thoracic aortic calcification (TAC) has not been investigated. This study aims to compare radial-VIBE to CT for the detection of TAC in the descending aorta of patients with end-stage renal disease (ESRD) using semi-automated methods, and to investigate the association between TAC and coronary artery calcification (CAC).

METHODS

Paired cardiac CT and radial-VIBE CMR scans from ESRD patients participating in 2 prospective studies were obtained. Calcification volume was quantified using semi-automated methods in a 9 cm segment of the thoracic aorta. Correlation and agreement between TAC volume measured on CMR and CT were assessed with Spearman's correlation coefficient (ρ), linear regression, Bland-Altman plots and intraclass correlation coefficient (ICC). Association between CAC Agatston score and TAC volume determined by CT and CMR was measured with Spearman's correlation coefficient.

RESULTS

Scans from 96 participants were analysed. Positive correlation was found between CMR and CT calcification volume [ρ = 0.61, 95% confidence interval (CI) 0.45-0.73]. ICC for consistency was 0.537 (95% CI 0.378-0.665). Bland-Altman plot revealed that compared to CT, CMR volumes were systematically higher at low calcification volume, and lower at high calcification volume. CT did not detect calcification in 41.7% of participants, while radial-VIBE CMR detected signal which the semi-quantitative algorithm reported as calcification in all of those individuals. Instances of suboptimal radial-VIBE CMR image quality were deemed to be the major contributors to the discrepancy. Correlations between CAC Agatston score and TAC volume measured by CT and CMR were ρ = 0.404 (95% CI 0.214-0.565) and ρ = 0.211 (95% CI 0.008-0.396), respectively.

CONCLUSION

Radial-VIBE CMR can detect TAC with strong positive association to CT, albeit with the presence of proportional bias. Quantification of vascular calcification by radial-VIBE remains a promising area for future research, but improvements in image quality are necessary.

The novel inflammatory marker GlycA and the prevalence and progression of valvular and thoracic aortic calcification: The Multi-Ethnic Study of Atherosclerosis

BACKGROUND AND AIMS

GlycA is a novel composite biomarker of systemic inflammation reflecting posttranslational glycosylation of acute phase reactants. GlycA has been associated with coronary artery calcium, cardiovascular disease (CVD) events and mortality. Vascular calcifications outside of the coronary arteries are risk markers of CVD and mortality. Whether GlycA is linked to extra-coronary calcifications (ECC) is not well established.

METHODS

We studied 6462 MESA participants free of clinical CVD who had plasma GlycA measured at baseline. ECCs [calcification in aortic valve (AVC), mitral annulus (MAC), ascending and descending thoracic aorta (ATAC, DTAC)] were ascertained at baseline and follow-up visit (median 2.3-yrs later) by cardiac CT. Poisson regression models with robust variance estimation assessed associations of GlycA with prevalent and incident ECC. Linear mixed models assessed the cross-sectional and 2-year change in ECC. Models were adjusted for demographic and lifestyle factors.

RESULTS

In cross-sectional analysis, GlycA (per SD increment) was positively associated with prevalent AVC, ATAC and DTAC with adjusted prevalence ratios (95% CI) of 1.08 (1.01-1.14), 1.18 (1.03-1.34) and 1.10 (1.06-1.14), respectively. There was also a significant association between GlycA and baseline extent of both ATAC and DTAC. Longitudinally, GlycA was positively associated with incident MAC and DTAC, with adjusted incidence ratios of 1.18 (1.03-1.37) and 1.17 (1.07-1.28), respectively. GlycA was also associated with 2-year change in MAC and DTAC extent.

CONCLUSIONS

In this diverse cohort free from clinical CVD, we found GlycA was positively associated with prevalent and incident ECC measures, in particular for progression of MAC and DTAC.

Thoracic aortic calcium, cardiovascular disease events, and all-cause mortality in asymptomatic individuals with zero coronary calcium: The Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND AND AIMS

TAC is associated with incident CVD and all-cause mortality. Nevertheless, the independent 10-year prognostic value of TAC in individuals with CAC = 0 beyond traditional risk factors is not well established.

METHODS

3415 MESA participants with baseline CAC = 0 were followed for CHD, CVD events and all-cause mortality. TAC was measured in the ascending and descending aorta in all participants and quantified using Agatston's score. Multivariable Cox proportional hazards regression models were used to study the associations between TAC and incident CHD, CVD events and all-cause mortality. Likelihood ratio tests were used to compare prediction models including traditional risk factors plus TAC versus risk factors alone.

RESULTS

406 participants (11.9%) had TAC>0 at baseline. Over a median follow-up of 11.3 years, unadjusted event rates per 1000 person-years were higher in TAC>0 than in TAC = 0 participants: CHD 2.18 vs. 2.03; CVD 6.85 vs. 3.42; all-cause mortality 12.84 vs. 4.96. However, in multivariable Cox regression analyses adjusting for CVD risk factors, neither TAC>0, TAC>100 nor log(TAC+1) were independently associated with any of the study outcomes, nor improved their prediction compared to traditional risk factors alone (p value of likelihood ratio tests >0.05).

CONCLUSIONS

In a multi-ethnic, modern US population of asymptomatic individuals with CAC = 0 at baseline, the prevalence of TAC>0 was low, and TAC did not improve 10-year estimation of prognosis beyond traditional risk factors. In the presence of CAC = 0, measurement of TAC is unlikely to provide sufficient additional prognostic information to further improve risk assessment.

Coronary artery calcification outperforms thoracic aortic calcification for the prediction of myocardial infarction and all-cause mortality: the Heinz Nixdorf Recall Study

BACKGROUND

Thoracic aortic calcification (TAC) is associated with cardiovascular (CV) risk factors and prevalent coronary artery disease. We aimed to investigate whether TAC burden is associated with incident myocardial infarction (MI) and all-cause mortality in subjects without known coronary artery disease and to determine its predictive value for these endpoints.

METHODS

We used longitudinal data from the population-based prospective Heinz Nixdorf Recall Study. TAC and coronary artery calcification (CAC) scores were quantified from non-contrast enhanced electron beam computed tomography. Cox regression analysis was used to determine the association of TAC with incident MI or all-cause mortality, adjusting for CV risk factors and additionally for CAC-score in a separate step. Predictive value of TAC was assessed using Harrell's C index.

RESULTS

Overall, 4040 participants without known coronary artery disease (59.4 years, 47% male) were included in this analysis. During a mean follow-up of 8.0 ± 1.5 years, we observed 136 coronary events and 304 deaths. In subjects with TAC>0 vs TAC = 0, the incidence of nonfatal MI was 4.2% vs 2.0% (p < 0.001), and all-cause mortality was 8.9% vs 5.2% (p < 0.001). Risks for coronary events and for all-cause mortality increased significantly with increasing TAC-scores (p < 0.001). After adjustment for CV risk factors, body mass index (BMI) and CV medication, a unit increase of TAC on a logarithmic scale (log(TAC + 1)) remained independently associated with coronary events (hazard ratio (HR) (95% confidence interval (CI)): 1.06 (1.00-1.14), p = 0.03) and all-cause mortality (HR 1.06 (1.01-1.12), p < 0.01). After further adjustment for CAC-score (log(CAC + 1)), hazard ratios were attenuated for both endpoints (coronary events: 0.98 (0.91-1.05), p = 0.56, all-cause mortality: 1.03 (0.98-1.08), p = 0.33). When adding log(TAC + 1) to the model containing traditional risk factors and CAC, Harrell's C indices did not increase for coronary events (0.773-0.772, p = 0.66) or for all-cause mortality (0.741-0.743, p = 0.49).

CONCLUSION

TAC is associated with incident coronary events and all-cause mortality independent of traditional CV risk factors in the general population. TAC fails to improve event prediction over CAC in both coronary events and all-cause mortality.