Opportunistic Screening for Coronary Artery Disease: An Untapped Population Health Resource

BACKGROUND

Coronary artery disease is the leading cause of death in the United States. At-risk asymptomatic adults are eligible for screening with electrocardiogram-gated coronary artery calcium (CAC) CT, which aids in risk stratification and management decision-making. Incidental CAC (iCAC) is easily quantified on chest CT in patients imaged for noncardiac indications; however, radiologists do not routinely report the finding.

OBJECTIVE

To determine the clinical significance of CAC identified incidentally on routine chest CT performed for noncardiac indications.

DESIGN

An informationist developed search strategies in MEDLINE, Embase, and SCOPUS, and two reviewers independently screened results at both the abstract and full text levels. Data extracted from eligible articles included age, rate of iCAC identification, radiologist reporting frequency, impact on downstream medical management, and association of iCAC with patient outcomes.

RESULTS

From 359 unique citations, 83 research publications met inclusion criteria. The percentage of patients with iCAC ranged from 9% to 100%. Thirty-one investigations measured association(s) between iCAC and cardiovascular morbidity and mortality, and 29 identified significant correlations, including nonfatal myocardial infarction, fatal myocardial infarction, major adverse cardiovascular event, cardiovascular death, and all-cause death. iCAC was present in 20% to 100% of the patients in these cohorts, but when present, iCAC was reported by radiologists in only 31% to 44% of cases. Between 18% and 77% of patients with iCAC were not on preventive medications in studies that reported these data. Seven studies measured the effect of reporting on guideline directed medical therapy, and 5 (71%) reported an increase in medication prescriptions after diagnosis of iCAC, with one confirming reductions in low-density lipoprotein levels. Twelve investigations reported good concordance between CAC grade on noncardiac CT and Agatston score on electrocardiogram-gated cardiac CT, and 10 demonstrated that artificial intelligence tools can reliably calculate an Agatston score on noncardiac CT.

CONCLUSION

A body of evidence demonstrates that patients with iCAC on routine chest CT are at risk for cardiovascular disease events and death, but they are often undiagnosed. Uniform reporting of iCAC in the chest CT impression represents an opportunity for radiology to contribute to early identification of high-risk individuals and potentially reduce morbidity and mortality. AI tools have been validated to calculate Agatston score on routine chest CT and hold the best potential for facilitating broad adoption.

Cardiovascular risk stratification among individuals with obesity: The Coronary Artery Calcium Consortium

OBJECTIVE

The effectiveness of coronary artery calcification (CAC) for risk stratification in obesity, in which imaging is often limited because of a reduced signal to noise ratio, has not been well studied.

METHODS

Data from 9334 participants (mean age: 53.3 ± 9.7 years; 67.9% men) with BMI ≥ 30 kg/m2 from the CAC Consortium, a retrospectively assembled cohort of individuals with no prior cardiovascular diseases (CVD), were used. The predictive value of CAC for all-cause and cause-specific mortality was evaluated using multivariable-adjusted Cox proportional hazards and competing-risks regression.

RESULTS

Mean BMI was 34.5 (SD 4.4) kg/m2 (22.7% Class II and 10.8% Class III obesity), and 5461 (58.5%) had CAC. Compared with CAC = 0, those with CAC = 1-99, 100-299, and ≥300 Agatston units had higher rates (per 1000 person-years) of all-cause (1.97 vs. 3.5 vs. 5.2 vs. 11.3), CVD (0.4 vs. 1.1 vs. 1.5 vs. 4.2), and coronary heart disease (CHD) mortality (0.2 vs. 0.6 vs. 0.6 vs. 2.5), respectively, after mean follow-up of 10.8 ± 3.0 years. After adjusting for traditional cardiovascular risk factors, CAC ≥ 300 was associated with significantly higher risk of all-cause (hazard ratio [HR]: 2.05; 95% CI: 1.49-2.82), CVD (subdistribution HR: 3.48; 95% CI: 1.81-6.70), and CHD mortality (subdistribution HR: 5.44; 95% CI: 2.02-14.66), compared with CAC = 0. When restricting the sample to individuals with BMI ≥ 35 kg/m2 , CAC ≥ 300 remained significantly associated with the highest risk.

CONCLUSIONS

Among individuals with obesity, including moderate-severe obesity, CAC strongly predicts all-cause, CVD, and CHD mortality and may serve as an effective cardiovascular risk stratification tool to prioritize the allocation of therapies for weight management.

Female-specific risk factors of parity and menopause age and risk of carotid plaque: the multi-ethnic study of atherosclerosis

BACKGROUND

Female-specific factors of grand multiparity (≥5 births) and early menopause age are associated with an increased risk of cardiovascular disease (CVD). However, mechanisms are incompletely understood. Carotid plaque is a marker of subclinical atherosclerosis and associated with increased CVD risk. We evaluated the association of female-specific factors with plaque burden.

METHODS

We included 2,313 postmenopausal women in the Multi-Ethnic Study of Atherosclerosis, free of clinical CVD, whose parity and menopause age were ascertained by questionnaires and carotid plaque measured by ultrasound at baseline and 10 years later. Parity was categorized as nulliparity (reference), 1-2, 3-4 and ≥5 live births. Menopause age was categorized as <45, 45-49, 50-54 (reference) and ≥55 years. Multivariable regression was performed to evaluate the association of parity and menopause age with carotid plaque presence (yes/no) and extent [carotid plaque score (CPS)].

RESULTS

The mean age was 64±9 years; 52.3% had prevalent carotid plaque at baseline. Compared to nulliparity, grand multiparity was significantly associated with prevalent carotid plaque after adjustment for CVD risk factors (prevalence ratio 1.17 (95% CI 1.03-1.35)) and progression of CPS over 10 years [percent difference 13% (95% CI 3-23)]. There was not any significant association of menopause age with carotid plaque presence or progression in fully-adjusted models.

CONCLUSION

In a multiethnic cohort, grand multiparity was independently associated with carotid plaque presence and progression. Early menopause, a known risk factor for CVD, was not captured by carotid plaque in this study. These findings may have implications for refining CVD risk assessment in women.

Cardiac computed tomographic imaging in cardio-oncology: An expert consensus document of the Society of Cardiovascular Computed Tomography (SCCT). Endorsed by the International Cardio-Oncology Society (ICOS)

Cardio-Oncology is a rapidly growing sub-specialty of medicine, however, there is very limited guidance on the use of cardiac CT (CCT) in the care of Cardio-Oncology patients. In order to fill in the existing gaps, this Expert Consensus statement comprised of a multidisciplinary collaboration of experts in Cardiology, Radiology, Cardiovascular Multimodality Imaging, Cardio-Oncology, Oncology and Radiation Oncology aims to summarize current evidence for CCT applications in Cardio-Oncology and provide practice recommendations for clinicians.

Prognostic significance of aortic valve calcium in relation to coronary artery calcification for long-term, cause-specific mortality: results from the CAC Consortium

AIMS

Aortic valve calcification (AVC) has been shown to be associated with increased cardiovascular disease (CVD) risk; however, whether this is independent of traditional risk factors and coronary artery calcification (CAC) remains unclear.

METHODS AND RESULTS

From the multicentre CAC Consortium database, 10 007 patients (mean 55.8±11.7 years, 64% male) with concomitant CAC and AVC scoring were included in the current analysis. AVC score was quantified using the Agatston score method and categorized as 0, 1-99, and ≥100. The endpoints were all-cause, CVD, and coronary heart disease (CHD) deaths. AVC (AVC>0) was observed in 1397 (14%) patients. During a median 7.8 (interquartile range: 4.7-10.6) years of study follow-up, 511 (5.1%) deaths occurred; 179 (35%) were CVD deaths, and 101 (19.8%) were CHD deaths. A significant interaction between CAC and AVC for mortality was observed (P<0.001). The incidence of mortality events increased with higher AVC; however, AVC ≥100 was not independently associated with all-cause, CVD, and CHD deaths after adjusting for CVD risk factors and CAC (P=0.192, 0.063, and 0.206, respectively). When further stratified by CAC<100 or ≥100, AVC ≥100 was an independent predictor of all-cause and CVD deaths only in patients with CAC <100, after adjusting for CVD risk factors and CAC [hazard ratio (HR): 1.93, 95% confidence interval (CI): 1.14-3.27; P=0.013 and HR: 2.71, 95% CI: 1.15-6.34; P=0.022, respectively].

CONCLUSION

Although the overall prognostic significance of AVC was attenuated after accounting for CAC, high AVC was independently associated with all-cause and CVD deaths in patients with low coronary atherosclerosis burden.

Greater IL-6, D-dimer, and ICAM-1 Levels Are Associated With Lower Small HDL Particle Concentration in the Multicenter AIDS Cohort Study

OBJECTIVE

Low HDL cholesterol (HDL-C) is common in people living with HIV infection, which is associated with inflammation, and correlates with greater cardiovascular disease (CVD) risk. Particles of HDL are HDL subfractions, and in some general population studies, higher small HDL particle number (HDL-P) has been associated with lower CVD risk. The objective of this study was to determine whether HIV serostatus and systemic inflammation were associated with small HDL-P in the Multicenter AIDS Cohort Study (MACS).

METHOD

The MACS is composed of HIV-infected and HIV-uninfected men. Separate linear regression analyses were conducted to evaluate the associations between outcomes (small HDL-P, large HDL-P, total HDL-P, and HDL size) and variables of interest (interleukin-6 [IL-6], D-dimer, and intercellular adhesion molecule-1 [ICAM-1] levels), with adjustment for other CVD risk factors.

RESULTS

The study population included 553 HIV-infected (88.1% on current ART) and 319 HIV-uninfected men. The mean age was 52.7 years for HIV-infected men and 55.3 years for HIV-uninfected men. In separate models of the study population, higher log IL-6 was associated with lower total and small HDL-P (P < .01 for both), independent of HIV serostatus and CVD risk factors. Similar results were seen with ICAM-1. Positive HIV serostatus was associated with lower small and total HDL-P, adjusted for inflammatory markers.

CONCLUSIONS

Greater systemic inflammation and HIV infection both were associated with lower atheroprotective small HDL-P. This may be a potential mechanism contributing to increased cardiovascular risk among HIV-infected people.

Higher cardiorespiratory fitness predicts long-term survival in patients with heart failure and preserved ejection fraction: the Henry Ford Exercise Testing (FIT) Project

INTRODUCTION

Higher cardiorespiratory fitness (CRF) is associated with improved exercise capacity and quality of life in heart failure with preserved ejection fraction (HFpEF), but there are no large studies evaluating the association of HFpEF, CRF, and long-term survival. We therefore aimed to determine the association between CRF and all-cause mortality, in patients with HFpEF.

MATERIAL AND METHODS

In the Henry Ford Exercise Testing (FIT) Project, 167 patients had baseline HFpEF, defined as a clinical diagnosis of heart failure with ejection fraction ≥ 50% on echocardiogram. The CRF was estimated from the peak workload (in METs) from a clinician-referred treadmill stress test and categorized as poor (1-4 METs), intermediate (5-6 METs), and moderate-high (≥ 7 METs). Additional analyses assessing the effect of HFpEF and CRF on mortality were also conducted, matching HFpEF patients to non-HFpEF patients using propensity scores.

RESULTS

Mean age was 64 ±13 years, with 55% women, and 46% Black. Over a median follow-up of 9.7 (5.2-18.9) years, there were 103 deaths. In fully adjusted models, moderate-high CRF was associated with 63% lower mortality risk (HR = 0.37, 95% CI: 0.18-0.73) compared to the poor-CRF group. In the propensity-matched cohort, HFpEF was associated with a HR of 2.3 (95% CI: 1.7-3.2) for mortality compared to non-HFpEF patients, which was attenuated to 1.8 (95% CI: 1.3-2.5) after adjusting for CRF.

CONCLUSIONS

Moderate-high CRF in patients with HFpEF is associated with improved survival, and differences in CRF partly explain the intrinsic risk of HFpEF. Randomized trials of interventions aimed at improving CRF in HFpEF are needed.

Sex Differences in Cardiorespiratory Fitness and All-Cause Mortality: The Henry Ford ExercIse Testing (FIT) Project

OBJECTIVE

To determine whether sex modifies the relationship between fitness and mortality.

PATIENTS AND METHODS

We included 57,284 patients without coronary artery disease or heart failure who completed a routine treadmill exercise test between 1991 and 2009. We determined metabolic equivalent tasks (METs) and linked patient records with mortality data via the Social Security Death Index. Multivariable Cox regression was used to determine the association between sex, fitness, and all-cause mortality.

RESULTS

There were 29,470 men (51.4%) and 27,814 women (48.6%) with mean ages of 53 and 54 years, respectively. Overall, men achieved 1.7 METs higher than women (P<.001). During median follow-up of 10 years, there were 6402 deaths. The mortality rate for men in each MET group was similar to that for women, who achieved an average of 2.6 METs lower (P=.004). Fitness was inversely associated with mortality in both men (hazard ratio [HR], 0.84 per 1 MET; 95% CI, 0.83-0.85) and women (HR, 0.83 per 1 MET; 95% CI, 0.81-0.84). This relationship did not plateau at high or low MET values.

CONCLUSION

Although men demonstrated 1.7 METs higher than women, their survival was equivalent to that of women demonstrating 2.6 METs lower. Furthermore, higher MET values were associated with lower mortality for both men and women across the range of MET values. These findings are useful for tailoring prognostic information and lifestyle guidance to men and women undergoing stress testing.

Rationale and design of the Henry Ford Exercise Testing Project (the FIT project)

Although physical fitness is a powerful prognostic marker in clinical medicine, most cardiovascular population-based studies do not have a direct measurement of cardiorespiratory fitness. In line with the call from the National Heart Lung and Blood Institute for innovative, low-cost, epidemiologic studies leveraging electronic medical record (EMR) data, we describe the rationale and design of the Henry Ford ExercIse Testing Project (The FIT Project). The FIT Project is unique in its combined use of directly measured clinical exercise data retrospective collection of medical history and medication treatment data at the time of the stress test, retrospective supplementation of supporting clinical data using the EMR and administrative databases and epidemiologic follow-up for cardiovascular events and total mortality via linkage with claims files and the death registry. The FIT Project population consists of 69 885 consecutive physician-referred patients (mean age, 54 ± 10 years; 54% males) who underwent Bruce protocol treadmill stress testing at Henry Ford Affiliated Hospitals between 1991 and 2009. Patients were followed for the primary outcomes of death, myocardial infarction, and need for coronary revascularization. The median estimated peak metabolic equivalent (MET) level was 10, with 17% of the patients having a severely reduced fitness level (METs < 6). At the end of the follow-up duration, 15.9%, 5.6%, and 6.7% of the patients suffered all-cause mortality, myocardial infarction, or revascularization procedures, respectively. The FIT Project is the largest study of physical fitness to date. With its use of modern electronic clinical epidemiologic techniques, it is poised to answer many clinically relevant questions related to exercise capacity and prognosis.

Usefulness of regional distribution of coronary artery calcium to improve the prediction of all-cause mortality

Although the traditional Agatston coronary artery calcium (CAC) score is a powerful predictor of mortality, it is unknown if the regional distribution of CAC further improves cardiovascular risk prediction. We retrospectively studied 23,058 patients referred for Agatston CAC scoring, of whom 61% had CAC (n=14,084). CAC distribution was defined as the number of vessels with CAC (0 to 4, including left main). For multivessel CAC, "diffuse" CAC was defined by decreasing percentage of CAC in the single most affected vessel and by ≤75% total Agatston CAC score in the most calcified vessel. All-cause mortality was ascertained through the social security death index. The mean age was 55±11 years, with 69% men. There were 584 deaths (2.5%) over 6.6±1.7 years. Considerable heterogeneity existed between the Agatston CAC score group and the number of vessels with CAC. In each CAC group, increasing number of vessels with CAC was associated with an increased mortality rate. After adjusting for age, gender, Agatston CAC score, and cardiovascular risk factors, increasing number of vessels with CAC was associated with higher mortality risk compared with single-vessel CAC (2-vessel: HR 1.61 [95% CI 1.14 to 2.25], 3-vessel: 1.99 [1.44 to 2.77], and 4-vessel: 2.22 [1.53 to 3.23]). "Diffuse" CAC was associated with a higher mortality rate in the CAC 101 to 400 and >400 groups. Left main CAC was associated with increased mortality risk. In conclusion, increasing number of vessels with CAC and left main CAC predict increased all-cause mortality and improve the prognostic power of the traditional Agatston CAC score.

Identification of incident CKD stage 3 in research studies

BACKGROUND

In epidemiologic research, incident chronic kidney disease (CKD) commonly is determined by laboratory tests performed at planned study visits. Given the morbidity and mortality associated with CKD, persons with incident disease may be less likely to attend scheduled visits, affecting observed associations. The objective of this study was to quantify loss to follow-up by CKD status and determine whether supplementation with diagnostic code data improves capture of incident CKD.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

11,560 participants in the Atherosclerosis Risk in Communities (ARIC) Study underwent continuous surveillance for hospitalizations and death from baseline visit (1996-1999) to follow-up visit (2011-2013). A subset of hospitalizations in Washington County, MD, was used in diagnostic code validation (n=2,540).

PREDICTOR

Baseline demographics and comorbid conditions.

OUTCOMES

Incident CKD stage 3 ascertained by follow-up visit (visit-based definition) or hospitalization surveillance (hospitalization-based definition).

MEASUREMENTS

Visit-based definition: ≥25% decline from baseline estimated glomerular filtration rate to <60 mL/min/1.73 m2 at follow-up visit; hospitalization-based definition: hospitalization CKD diagnostic code.

RESULTS

Of 11,560 participants, 5,951 attended the follow-up visit and 9,264 were hospitalized. Never-hospitalized participants were younger, more often female, and had fewer comorbid conditions; 73.5% attended the follow-up visit. Incident CKD stage 3 occurred in 1,172 participants by the visit-based definition (251 were never hospitalized) and 1,078 participants by the hospitalization-based definition (237 attended the follow-up study visit). Sensitivity of the hospitalization-based CKD definition was 35.5% (95% CI, 31.6%-39.7%); specificity was 95.7% (95% CI, 94.2%-96.8%). Sensitivity was higher with later time period, older participant age, and baseline prevalent diabetes and CKD.

LIMITATIONS

A subset of hospitalizations was used for validation; 15-year gap between study visits.

CONCLUSIONS

The sensitivity of diagnostic code-identified CKD is low and varies by certain factors; however, supplementing a visit-based definition with hospitalization information can increase disease identification during periods of follow-up without study visits.

Performance and limitations of administrative data in the identification of AKI

BACKGROUND AND OBJECTIVES

Billing codes are frequently used to identify AKI events in epidemiologic research. The goals of this study were to validate billing code-identified AKI against the current AKI consensus definition and to ascertain whether sensitivity and specificity vary by patient characteristic or over time.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The study population included 10,056 Atherosclerosis Risk in Communities study participants hospitalized between 1996 and 2008. Billing code-identified AKI was compared with the 2012 Kidney Disease Improving Global Outcomes (KDIGO) creatinine-based criteria (AKIcr) and an approximation of the 2012 KDIGO creatinine- and urine output-based criteria (AKIcr_uop) in a subset with available outpatient data. Sensitivity and specificity of billing code-identified AKI were evaluated over time and according to patient age, race, sex, diabetes status, and CKD status in 546 charts selected for review, with estimates adjusted for sampling technique.

RESULTS

A total of 34,179 hospitalizations were identified; 1353 had a billing code for AKI. The sensitivity of billing code-identified AKI was 17.2% (95% confidence interval [95% CI], 13.2% to 21.2%) compared with AKIcr (n=1970 hospitalizations) and 11.7% (95% CI, 8.8% to 14.5%) compared with AKIcr_uop (n=1839 hospitalizations). Specificity was >98% in both cases. Sensitivity was significantly higher in the more recent time period (2002-2008) and among participants aged 65 years and older. Billing code-identified AKI captured a more severe spectrum of disease than did AKIcr and AKIcr_uop, with a larger proportion of patients with stage 3 AKI (34.9%, 19.7%, and 11.5%, respectively) and higher in-hospital mortality (41.2%, 18.7%, and 12.8%, respectively).

CONCLUSIONS

The use of billing codes to identify AKI has low sensitivity compared with the current KDIGO consensus definition, especially when the urine output criterion is included, and results in the identification of a more severe phenotype. Epidemiologic studies using billing codes may benefit from a high specificity, but the variation in sensitivity may result in bias, particularly when trends over time are the outcome of interest.

NH2-terminal pro-brain natriuretic peptide and risk of diabetes

Brain natriuretic peptide (BNP) has an established role in cardiovascular disease (CVD). However, recent animal studies suggest direct metabolic effects of BNP. To determine the association of BNP with the risk of diabetes, we conducted a prospective analysis of participants from the Atherosclerosis Risk in Communities (ARIC) study. We included 7,822 men and women without history of diabetes, CVD, or reduced kidney function at baseline. At baseline, NH2-terminal (NT)-proBNP, a cleavage product of BNP, was inversely associated with adiposity, fasting glucose, insulin, and cholesterol but positively associated with blood pressure and C-reactive protein levels. During a median follow-up of 12 years, 1,740 participants reported a new diagnosis of diabetes or medication use for diabetes. Baseline quartiles of NT-proBNP were inversely associated with diabetes risk, even after multivariable adjustment including fasting glucose. The adjusted HRs for diabetes were 1.0 (reference), 0.84 (95% CI 0.74-0.96), 0.79 (95% CI 0.68-0.90), and 0.75 (95% CI 0.64-0.87) for the 1st, 2nd, 3rd, and 4th quartiles of baseline NT-proBNP, respectively (P for trend <0.001). This inverse association was robust across sex, race, and obesity subgroups. Our results extend animal studies and support a direct and important metabolic role of BNP in humans.

Dyslipidemia Management for Secondary Prevention in Women with Cardiovascular Disease: What Can We Expect From Non-pharmacologic Strategies?

Cardiovascular disease is the leading cause of death in women and the treatment of dyslipidemia is a cornerstone of secondary prevention. Pharmacologic therapy with statins can lower LDL-C by 30-50% and reduce the risk of recurrent coronary heart disease in both men and women. While significant reductions in LDL-C can be achieved with statin therapy, diet and lifestyle modification remain an essential part of the treatment regimen for cardiovascular disease. Moreover, a large proportion of the U.S. population is sedentary, overweight, and does not consume a heart-healthy diet. Non-pharmacologic treatment strategies also improve other cardiovascular risk factors and are generally easily accessible. In this review, we examine the effect of non-pharmacologic therapy on lipids as part of the secondary prevention strategy of cardiovascular disease in women.