Utility of routine non-gated CT chest in detection of subclinical atherosclerotic calcifications of coronary arteries in hospitalised HIV patients

Prevalence and clinical implications of coronary artery calcium scoring on non-gated thoracic computed tomography: a systematic review and meta-analysis

OBJECTIVES

Coronary artery calcifications (CACs) indicate the presence of coronary artery disease. CAC can be found on thoracic computed tomography (CT) conducted for non-cardiac reasons. This systematic review and meta-analysis of non-gated thoracic CT aims to assess the clinical impact and prevalence of CAC.

METHODS

Online databases were searched for articles assessing prevalence, demographic characteristics, accuracy and prognosis of incidental CAC on non-gated thoracic CT. Meta-analysis was performed using a random effects model.

RESULTS

A total of 108 studies (113,406 patients) were included (38% female). Prevalence of CAC ranged from 2.7 to 100% (pooled prevalence 52%, 95% confidence interval [CI] 46-58%). Patients with CAC were older (pooled standardised mean difference 0.88, 95% CI 0.65-1.11, p < 0.001), and more likely to be male (pooled odds ratio [OR] 1.95, 95% CI 1.55-2.45, p < 0.001), with diabetes (pooled OR 2.63, 95% CI 1.95-3.54, p < 0.001), hypercholesterolaemia (pooled OR 2.28, 95% CI 1.33-3.93, p < 0.01) and hypertension (pooled OR 3.89, 95% CI 2.26-6.70, p < 0.001), but not higher body mass index or smoking. Non-gated CT assessment of CAC had excellent agreement with electrocardiogram-gated CT (pooled correlation coefficient 0.96, 95% CI 0.92-0.98, p < 0.001). In 51,582 patients, followed-up for 51.6 ± 27.4 months, patients with CAC had increased all cause mortality (pooled relative risk [RR] 2.13, 95% CI 1.57-2.90, p = 0.004) and major adverse cardiovascular events (pooled RR 2.91, 95% CI 2.26-3.93, p < 0.001). When CAC was present on CT, it was reported in between 18.6% and 93% of reports.

CONCLUSION

CAC is a common, but underreported, finding on non-gated CT with important prognostic implications.

CLINICAL RELEVANCE STATEMENT

Coronary artery calcium is an important prognostic indicator of cardiovascular disease. It can be assessed on non-gated thoracic CT and is a commonly underreported finding. This represents a significant population where there is a potential missed opportunity for lifestyle modification recommendations and preventative therapies. This study aims to highlight the importance of reporting incidental coronary artery calcium on non-gated thoracic CT.

KEY POINTS

• Coronary artery calcification is a common finding on non-gated thoracic CT and can be reliably identified compared to gated-CT. • Coronary artery calcification on thoracic CT is associated with an increased risk of all cause mortality and major adverse cardiovascsular events. • Coronary artery calcification is frequently not reported on non-gated thoracic CT.

Accurate measurement of coronary artery calcium in cancer patients using the CT component of PET/CT scans

OBJECTIVE

The aim of this study is to establish the correlation between a CAC score derived from the CT component of PET/CT scan (CAC-PET) using in-house software as compared to the conventional technique (CAC-Standard). In addition, the incidence of high CAC scores in asymptomatic cancer patients with low-to-intermediate cardiovascular risk will be determined.

METHODS

100 patients referred for oncologic PET/CT were prospectively recruited to have a conventional CAC score after their PET/CT. Patients with a history of cardiac disease were excluded. The nongated CT images from the PET/CT (CAC-PET) were analysed using validated in-house software with the results compared to those from gated CT analysed using the standard technique (CAC-Standard).

RESULTS

The correlation of CAC scores between the two scan types was moderate [slope, 0.95; R2 = 0.91; limits of agreement (LOA) = 0.29-5.65]. Using a conventional categorical analysis, there was complete agreement in 73% of patients with one category difference in the remainder. [interclass correlation (ICC) = 0.90; Cohen's kappa = 0.63]. In total 28% of these asymptomatic low-to-intermediate-risk cancer patients had CAC scores over 300.

CONCLUSION

Estimation of CAC from the CT component of PET/CT scans is a reliable method for the detection of significant CAC in cancer patients and correlates well with the standard method. This technique should permit the calculation of cardiovascular risk in cancer patients undergoing PET/CT without any additional radiation exposure. A significant number of asymptomatic low-to-intermediate-risk cancer patients were found to have a high risk of cardiovascular disease.

Coronary Artery Calcification and Plaque Characteristics in People Living With HIV: A Systematic Review and Meta-Analysis

Background

Studies have reported that people living with HIV have higher burden of subclinical cardiovascular disease, but the data are not adequately synthesized. We performed meta‐analyses of studies of coronary artery calcium and coronary plaque in people living with HIV.

Methods and Results

We performed systematic search in electronic databases, and data were abstracted in standardized forms. Study‐specific estimates were pooled using meta‐analysis. 43 reports representing 27 unique studies and involving 10 867 participants (6699 HIV positive, 4168 HIV negative, mean age 52 years, 86% men, 32% Black) were included. The HIV‐positive participants were younger (mean age 49 versus 57 years) and had lower Framingham Risk Score (mean score 6 versus 18) compared with the HIV‐negative participants. The pooled estimate of percentage with coronary artery calcium >0 was 45% (95% CI, 43%–47%) for HIV‐positive participants, and 52% (50%–53%) for HIV‐negative participants. This difference was no longer significant after adjusting for difference in Framingham Risk Score between the 2 groups. The odds ratio of coronary artery calcium progression for HIV‐positive versus ‐negative participants was 1.64 (95% CI, 0.91–2.37). The pooled estimate for prevalence of noncalcified plaque was 49% (95% CI, 47%–52%) versus 20% (95% CI, 17%–23%) for HIV‐positive versus HIV‐negative participants, respectively. Odds ratio for noncalcified plaque for HIV‐positive versus ‐negative participants was 1.23 (95% CI, 1.08–1.38). There was significant heterogeneity that was only partially explained by available study‐level characteristics.

Conclusions

People living with HIV have higher prevalence of noncalcified coronary plaques and similar prevalence of coronary artery calcium, compared with HIV‐negative individuals. Future studies on coronary artery calcium and plaque progression can further elucidate subclinical atherosclerosis in people living with HIV.

Coronary Artery Disease in Patients with HIV Infection: An Update

Premature cardiovascular disease among the HIV-infected population is of great concern among clinicians. The increased life expectancy of HIV-infected individuals is mainly due to the early detection of infection and the advent of antiretroviral therapy. Once known as a deadly disease, HIV infection has transitioned into a chronic condition. Cardiovascular disease in this population is thought to progress early due to traditional and non-traditional risk factors. Early detection of subclinical atherosclerosis has become a center of focus in research as our complete understanding of this process it not yet well known. Advancements in cardiac computed tomography angiography has enabled the exploration of coronary artery disease by further evaluation of coronary stenosis and plaque analysis. An increase in cardiovascular event rates in this population is currently thought to be linked to antiretroviral therapy, Framingham risk factors, and HIV. We sought to present an updated comprehensive review of the available literature on HIV related to atherosclerosis and cardiovascular risk.