Examining the Potential for Coronary Artery Calcium (CAC) Scoring for Individuals at Low Cardiovascular Risk

Association between the homeostasis model assessment of insulin resistance and coronary artery calcification: a meta-analysis of observational studies

Background

Insulin resistance (IR), a risk factor for cardiovascular diseases, has garnered significant attention in scientific research. Several studies have investigated the correlation between IR and coronary artery calcification (CAC), yielding varying results. In light of this, we conducted a systematic review to investigate the association between IR as evaluated by the homeostasis model assessment (HOMA-IR) and CAC.

Methods

A comprehensive search was conducted to identify relevant studies in PubMed, Embase, Scopus, and Web of Science databases. In addition, preprint servers such as Research Square, BioRxiv, and MedRxiv were manually searched. The collected data were analyzed using either fixed or random effects models, depending on the heterogeneity observed among the studies. The assessment of the body of evidence was performed using the GRADE approach to determine its quality.

Results

The current research incorporated 15 studies with 60,649 subjects. The analysis revealed that a higher category of HOMA-IR was associated with a greater prevalence of CAC in comparison to the lowest HOMA-IR category, with an OR of 1.13 (95% CI: 1.06-1.20, I2 = 29%, P < 0.001). A similar result was reached when HOMA-IR was analyzed as a continuous variable (OR: 1.27, 95% CI: 1.14-1.41, I2 = 54%, P < 0.001). In terms of CAC progression, a pooled analysis of two cohort studies disclosed a significant association between increased HOMA-IR levels and CAC progression, with an OR of 1.44 (95% CI: 1.04-2.01, I2 = 21%, P < 0.05). It is important to note that the strength of the evidence was rated as low for the prevalence of CAC and very low for the progression of CAC.

Conclusion

There is evidence to suggest that a relatively high HOMA-IR may be linked with an increased prevalence and progression of CAC.

Utility of coronary artery calcium in refining 10-year ASCVD risk prediction using a Thai CV risk score

Background

Coronary artery calcium (CAC) scanning is a valuable additional tool for calculating the risk of cardiovascular (CV) events. We aimed to determine if a CAC score could improve performance of a Thai CV risk score in prediction of 10-year atherosclerotic cardiovascular disease (ASCVD) risk for asymptomatic patients with CV risk factors.

Methods

This was a retrospective cohort study that enrolled asymptomatic patients with CV risk factors who underwent CAC scans between 2005 and 2013. The patients were classified as low-, intermediate-, or high-risk (<10%, 10%-<20%, and ≥20%, respectively) of having ASCVD within 10-years based on a Thai CV risk score. In each patient, CAC score was considered as a categorical variable (0, 1-99, and ≥100) and natural-log variable to assess the risk of developing CV events (CV death, non-fatal MI, or non-fatal stroke). The C statistic and the net reclassification improvement (NRI) index were applied to assess whether CAC improved ASCVD risk prediction.

Results

A total of 6,964 patients were analyzed (mean age: 59.0 ± 8.4 years; 63.3% women). The majority of patients were classified as low- or intermediate-risk (75.3% and 20.5%, respectively), whereas only 4.2% were classified as high-risk. Nearly half (49.7%) of patients had a CAC score of zero (no calcifications detected), while 32.0% had scores of 1-99, and 18.3% of ≥100. In the low- and intermediate-risk groups, patients with a CAC ≥100 experienced higher rates of CV events, with hazard ratios (95% CI) of 1.95 (1.35, 2.81) and 3.04 (2.26, 4.10), respectively. Incorporation of ln(CAC + 1) into their Thai CV risk scores improved the C statistic from 0.703 (0.68, 0.72) to 0.716 (0.69, 0.74), and resulted in an NRI index of 0.06 (0.02, 0.10). To enhance the performance of the Thai CV risk score, a revision of the CV risk model was performed, incorporating ln(CAC + 1), which further increased the C statistic to 0.771 (0.755, 0.788).

Conclusion

The addition of CAC to traditional risk factors improved CV risk stratification and ASCVD prediction. Whether this adjustment leads to a reduction in CV events and is cost-effective will require further assessment.

Predictive value of lipoprotein(a) in coronary artery calcification among asymptomatic cardiovascular disease subjects: A systematic review and meta-analysis

AIMS

Studies have indicated inconsistent results regarding the association between plasma levels of Lipoprotein(a) [Lp(a)] and coronary artery calcification (CAC). We performed a systematic review and meta-analysis to investigate the association between elevated levels of Lp(a) and risk of CAC in populations free of cardiovascular disease (CVD) symptoms.

DATA SYNTHESIS

PubMed, Web of Science, Embase, and Scopus were searched up to July 2022 and the methodological quality was assessed using Newcastle-Ottawa Scale (NOS) scale. Random-effects meta-analysis was used to estimate pooled odds ratio (OR) and 95% confidence interval. Out of 298 studies, data from 8 cross-sectional (n = 18,668) and 4 cohort (n = 15,355) studies were used in meta-analysis. Cohort studies demonstrated a positive significant association between Lp(a) and CAC, so that individuals with Lp(a)≥30-50 exposed to about 60% risk of CAC incidence compared to those with lower Lp(a) concentrations in asymptomatic CVD subjects (OR, 1.58; 95% CI, 1.38-1.80; l2, 0.0%; P, 0.483); Subgroup analysis showed that a cut-off level for Lp(a) measurement could not statistically affect the association, but race significantly affected the relationship between Lp(a) and CAC (OR,1.60; 95% CI, 1.41-1.81). Analyses also revealed that both men and women with higher Lp(a) concentrations are at the same risk for increased CAC.

CONCLUSIONS

Blood Lp(a) level was significantly associated with CAC incidence in asymptomatic populations with CVD, indicating that measuring Lp(a) may be a useful biomarker for diagnosing subclinical atherosclerosis in individuals at higher risk of CAC score.

PROSPERO REGISTRATION NUMBER

CRD42022350297.

Early outcomes following integration of computed tomography (CT) coronary angiography service in an established cardiology practice in disease management

BACKGROUND

Computed tomography coronary angiography (CTCA) is an established modality for the diagnosis and assessment of cardiovascular disease. However, price and space pressure have mostly necessitated outsourcing CTCA to external radiology providers. Advara HeartCare has recently integrated CT services within local clinical networks across Australia. This study examined the benefits of the presence (integrated) or absence (pre-integrated) of this "in-house" CTCA service in real-world clinical practice.

METHODS

De-identified patient data from electronic medical records were used to create an Advara HeartCare CTCA database. Data analysis included clinical history, demographics, CTCA procedure, and 30-day outcomes post-CTCA from two age-matched cohorts: integrated (n ​= ​495) and pre-integrated (n ​= ​456).

RESULTS

Data capture was more comprehensive and standardised across the integrated cohort. There was a 21% increase in referrals for CTCA from cardiologists observed for the integration cohort vs. pre-integration [n ​= ​332 (72.8%) pre-integration vs. n ​= ​465 (93.9%) post-integration, p ​< ​0.0001] with a parallel increase in diagnostic assessments including blood tests [n ​= ​209 (45.8%) vs. n ​= ​387 (78.1%), respectively, p ​< ​0.0001]. The integrated cohort received lower total dose length product [Median 212 (interquartile range 136-418) mGy∗cm vs. 244 (141.5, 339.3) mGy∗cm, p ​= ​0.004] during the CTCA procedure. 30-days after CTCA scan, there was a significantly higher use of lipid-lowering therapies in the integrated cohort [n ​= ​133 (50.5%) vs. n ​= ​179 (60.6%), p ​= ​0.04], along with a significant decrease in the number of stress echocardiograms performed [n ​= ​14 (10.6%) vs. n ​= ​5 (11.6%), p ​= ​0.01].

CONCLUSION

Integrated CTCA has salient benefits in patient management, including increased pathology tests, statin usage, and decreased post-CTCA stress echocardiography utilisation. Our ongoing work will examine the effect of integration on cardiovascular outcomes.

Higher mortality in acute coronary syndrome patients without standard modifiable risk factors: Results from a global meta-analysis of 1,285,722 patients

BACKGROUND

Standard modifiable cardiovascular risk factors (SMuRF), comprising diabetes, hyperlipidemia, hypertension, and smoking, are used for risk stratification in acute coronary syndrome (ACS). Recent studies showed an increasing proportion of SMuRF-less ACS patients.

METHODS

Embase, Medline and Pubmed were searched for studies comparing SMuRF-less and SMuRF patients with first presentation of ACS. We conducted single-arm analyses to determine the proportion of SMuRF-less patients in the ACS cohort, and compared the clinical presentation and outcomes of these patients.

RESULTS

Of 1,285,722 patients from 15 studies, 11.56% were SMuRF-less. A total of 7.44% of non-ST-segment-elevation ACS patients and 12.87% of ST-segment-elevation myocardial infarction (STEMI) patients were SMuRF-less. The proportion of SMuRF-less patients presenting with STEMI (60.71%) tended to be higher than those with SMuRFs (49.21%). Despite lower body mass index and fewer comorbidities such as chronic kidney disease, peripheral arterial disease, stroke and heart failure, SMuRF-less patients had increased in-hospital mortality (RR:1.57, 95%CI:1.38 to 1.80) and cardiogenic shock (RR:1.39, 95%CI:1.18 to 1.65), but lower risk of heart failure (RR:0.91, 95%CI:0.83 to 0.99). On discharge, SMuRF-less patients were prescribed less statins (RR:0.93, 95%CI:0.91 to 0.95), beta-blockers (RR:0.94, 95%CI:0.92 to 0.96), P2Y12 inhibitors (RR: 0.98, 95%CI: 0.96 to 0.99), and angiotensin-converting-enzyme inhibitor or angiotensin-receptor blocker (RR:0.92, 95%CI:0.75 to 0.91).

CONCLUSION

In this study level meta-analysis, SMuRF-less ACS patients demonstrate higher mortality compared with patients with at least one traditional atherosclerotic risk factor. Underuse of guideline-directed medical therapy amongst SMuRF-less patients is concerning. Unraveling novel risk factors amongst SMuRF-less individuals is the next important step.

SUMMARY

Standard modifiable cardiovascular risk factors (SMuRF), comprising diabetes mellitus, hyperlipidemia, hypertension, and smoking, are often used for risk stratification in acute coronary syndrome (ACS). Recent studies showed an increasing proportion of SMuRF-less ACS patients. Of 1,285,722 ACS patients, 11.56% were SMuRF-less. Despite lower body mass index and fewer comorbidities, SMuRF-less patients had increased in-hospital mortality and cardiogenic shock. However, despite worse outcomes, SMuRF-less patients were prescribed less guideline-directed medical therapies on discharge.