Application and Clinical Value of Definitive Drug Monitoring in Pain Management and Addiction Medicine.

OBJECTIVE: To assess routine application and clinical value of definitive urine drug monitoring (UDM) for drug detection, inconsistent drug use, and prescription adherence, along with a comparison to immunoassay screening (IAS). METHODS: Direct-to-definitive UDM performance was analyzed retrospectively in 5000 patient specimens. Drug findings, medication inconsistencies, and detection sensitivity were assessed, and definitive UDM versus IAS monitoring was studied. RESULTS: Definitive testing resulted in 18,793 drug findings with 28,403 positive drug and metabolite tests. Definitive testing expanded monitoring with 11,396 drug findings that would not be tested by IAS. The opioids accounted for the highest frequency of inconsistent positive drug-use findings, at 12%. Conversely, inconsistent negative drug findings, used as an index of prescription non-adherence, were determined in 1,751 of 15,409 monitored medications and included a high frequency of antidepressants and antipsychotics inconsistencies. Direct comparison of definitive UDM and IAS showed false-positives by IAS as well as a high rate of false-negatives that would be missed using current confirmation protocols. CONCLUSIONS: Results from routine application of direct-to-definitive UDM demonstrate the clinical value of drug-use identification and the objective evaluation of inconsistencies in drug misuse and medication adherence in pain management and addiction medicine practice. Without conversion to direct-to-definitive UDM, continuing use of IAS will limit the scope of drugs being tested, will result in an indeterminate rate of false negatives and will require confirmation testing to eliminate the reporting of false-positive IAS tests. The findings in this study provide evidence-based support for recommended use of a direct-to-definitive drug testing protocol.

Electron Beam CT: A Historical Review.

OBJECTIVE. At its advent, CT was too slow to image the heart. Temporal resolution improved with electron beam CT (EBCT); subsequently, the heart could be imaged, eventually leading to the discovery of prognostic information obtained from the coronary calcium score. In the early 2000s, EBCT was replaced by MDCT. In this review, we discuss the rise and fall of EBCT and explore its legacy in cardiac imaging. CONCLUSION. Although MDCT rendered EBCT obsolete, EBCT leaves a legacy in cardiac imaging regarding both diagnosis and prognosis. The creators of MDCT emulated the strengths of EBCT and learned from its weaknesses. Moreover, EBCT showed that imaging surrogates can predict outcomes, and the origins of substrate-guided treatment can be traced to EBCT.

Sex differences in calcified plaque and long-term cardiovascular mortality: observations from the CAC Consortium.

Aims: Pathologic evidence supports unique sex-specific mechanisms as precursors for acute cardiovascular (CV) events. Current evidence on long-term CV risk among women when compared with men based on measures of coronary artery calcium (CAC) remains incomplete. Methods and results: A total of 63 215 asymptomatic women and men were enrolled in the multicentre, CAC Consortium with median follow-up of 12.6 years. Pooled cohort equation (PCE) risk scores and risk factor data were collected with the Agatston score and other CAC measures (number of lesions and vessels, lesion size, volume, and plaque density). Cox proportional hazard models were employed to estimate CV mortality (n = 919). Sex interactions were calculated. Women and men had average PCE risk scores of 5.8% and 9.1% (P < 0.001). Within CAC subgroups, women had fewer calcified lesions (P < 0.0001) and vessels (P = 0.017), greater lesion size (P < 0.0001), and higher plaque density (P = 0.013) when compared with men. For women and men without CAC, long-term CV mortality was similar (P = 0.67), whereas detectable CAC was associated with 1.3-higher hazard for CV death among women when compared with men (P < 0001). Cardiovascular mortality was higher among women with more extensive, numerous, or larger CAC lesions. The relative hazard for cardiovascular disease (CVD) mortality for women and men was 8.2 vs. 5.1 for multivessel CAC, 8.6 vs. 5.9 for ≥5 CAC lesions, and 8.5 vs. 4.4 for a lesion size ≥15 mm3, respectively. Additional explorations revealed that women with larger sized and more numerous CAC lesions had 2.2-fold higher CVD mortality (P < 0.0001) as compared to men. Moreover, CAC density was not predictive of CV mortality in women (P = 0.51) but was for men (P < 0.001), when controlling for CAC volume and cardiac risk factors. Conclusion: Our overall findings support that measures beyond the Agatston score provide important clues to sex differences in atherosclerotic plaque and may further refine risk detection and focus preventive strategies of care.

Left Main Coronary Artery Calcium and Diabetes Confer Very-High-Risk Equivalence in Coronary Artery Calcium >1,000.

BACKGROUND: Although a coronary artery calcium (CAC) of ≥1,000 is a subclinical atherosclerosis threshold to consider combination lipid-lowering therapy, differentiating very high from high atherosclerotic cardiovascular disease (ASCVD) risk in this patient population is not well-defined. OBJECTIVES: Among persons with a CAC of ≥1,000, the authors sought to identify risk factors equating with very high-risk ASCVD mortality rates. METHODS: The authors studied 2,246 asymptomatic patients with a CAC of ≥1,000 from the CAC Consortium without a prior ASCVD event. Cox proportional hazards regression modelling was performed for ASCVD mortality during a median follow-up of 11.3 years. Crude ASCVD mortality rates were compared with those reported for secondary prevention trial patients classified as very high risk, defined by ≥2 major ASCVD events or 1 major event and ≥2 high-risk conditions (1.4 per 100 person-years). RESULTS: The mean age was 66.6 years, 14% were female, and 10% were non-White. The median CAC score was 1,592 and 6% had severe left main (LM) CAC (vessel-specific CAC ≥300). Diabetes (HR: 2.04 [95% CI: 1.47-2.83]) and severe LM CAC (HR: 2.32 [95% CI: 1.51-3.55]) were associated with ASCVD mortality. The ASCVD mortality per 100 person-years for all patients was 0.8 (95% CI: 0.7-0.9), although higher rates were observed for diabetes (1.4 [95% CI: 0.8-1.9]), severe LM CAC (1.3 [95% CI: 0.6-2.0]), and both diabetes and severe LM CAC (7.1 [95% CI: 3.4-10.8]). CONCLUSIONS: Among asymptomatic patients with a CAC of ≥1,000 without a prior index event, diabetes, and severe LM CAC define very high risk ASCVD, identifying individuals who may benefit from more intensive prevention therapies across several domains, including low-density lipoprotein-cholesterol lowering.

Coronary Artery Calcium for Risk Stratification Among Persons With Very High HDL Cholesterol.

Background: Compared to normal high-density lipoprotein (HDL) cholesterol values, very high HDL cholesterol is associated with a higher incidence of mortality and atherosclerotic cardiovascular disease (ASCVD). As such, clinical risk stratification among persons with very high HDL cholesterol is challenging. Objectives: Among persons with very high HDL cholesterol, the purpose was to determine the prevalence of coronary artery calcium (CAC) and compare the association between traditional risk factors vs CAC for all-cause mortality and ASCVD. Methods: The primary analysis was completed among 446 participants from the Cedars-Sinai Medical Center of the CAC Consortium with very high HDL cholesterol (≥77 mg/dL in men, ≥97 mg/dL in women). Cox proportional hazards regression assessed the association of CAC and traditional risk factors with all-cause mortality during a median follow-up of 10.7 years. Replication and validation analyses were performed for all-cause mortality among 119 participants from the Multi-Ethnic Study of Atherosclerosis (MESA) with very high HDL cholesterol, who also had information on incident ASCVD. Results: The mean age was 57.9 years old, 49% were women, and the median HDL cholesterol was 98 mg/dL. One-half of participants (50%) had prevalent CAC, in whom the median CAC score was 118. Prevalent CAC conferred a 3.6-fold higher risk of all-cause mortality (HR: 3.64; 95% CI: 1.21-11.01), which appeared to be a more robust predictor than individual traditional risk factors beyond age. In the validation sample, prevalent CAC but not individual traditional risk factors were associated with all-cause mortality (HR: 2.39; 95% CI: 1.07-5.34) and a 4.0-fold higher risk of ASCVD (HR: 4.06; 95% CI: 1.11-14.84). Conclusions: Measurement of CAC may facilitate clinical risk assessment among individuals with very high HDL cholesterol.

Coronary artery calcium for the prediction of mortality in young adults <45 years old and elderly adults >75 years old.

AIMS: To determine if coronary artery calcium (CAC) scoring is independently predictive of mortality in young adults and in the elderly population and if a young person with high CAC has a higher mortality risk than an older person with less CAC. METHODS AND RESULTS: We studied a cohort of 44 052 asymptomatic patients referred for CAC scans for cardiovascular risk stratification. All-cause mortality rates (MRs) were calculated after stratifying by age groups (<45, 45-54, 55-64, 65-74, and ≥75) and CAC score (0, 1-100, 100-400, and >400). Multivariable Cox regression models were constructed to assess the independent value of CAC for predicting all-cause mortality in the <45- and ≥75-year-old age groups. The MR increased in both the <45- and ≥75-year-old age groups with an increasing CAC group. After multivariable adjustment, increasing CAC remained independently predictive of increased mortality compared with CAC = 0 [<45 age group, hazard ratio (95% confidence interval): CAC = 1-100, 2.3 (1.2-4.2); CAC = 100-400, 7.4 (3.3-16.6); CAC > 400, 34.6 (15.5-77.4); ≥75 age group: CAC = 1-100, 7.0 (2.4-20.8); CAC = 100-400, 9.2 (3.2-26.5); CAC > 400, 16.1 (5.8-45.1)]. Persons <45 years old with CAC = 100-400 and CAC > 400 had 2- and 10-fold increased MRs, respectively, compared with persons ≥75 with no CAC. Individuals ≥75 years old with CAC = 0 had a 5.6-year survival rate of 98%, similar to those in other age groups with CAC = 0 (5.6-year survival, 99%). CONCLUSION: The value of CAC for predicting mortality extends to both elderly patients and those <45 years old. Elderly persons with no CAC have a lower MR than younger persons with high CAC.

Going beyond the coronaries: Routine cardiovascular risk assessment reveals rare incidental thymoma.

Thymomas are rare anterior mediastinal masses that present with local or paraneoplastic symptoms. Definitive diagnosis requires tissue sampling but early detection leads to early intervention and improved outcomes. We present a case where routine cardiovascular risk assessment identified an incidental and rare thymoma. Final specimen pathology revealed a Thymoma WHO Type AB (30% A, 70% B). Routine cardiovascular risk assessment which often includes coronary artery calcium scanning and cardiovascular computed tomographic angiography may reveal pathology beyond the coronary arteries. Early detection of asymptomatic mediastinal masses facilitates early intervention and can improve outcomes.

Impact of visceral fat on coronary artery disease as defined by quantitative computed tomography angiography.

OBJECTIVE: Obesity is associated with all-cause mortality and cardiovascular disease (CVD). Visceral fat (VF) is an important CVD risk metric given its independent correlation with myocardial infarction and stroke. This study aims to clarify the relationship between the presence and severity of VF with the presence and severity of coronary artery plaque. METHODS: In 145 consecutive asymptomatic patients, atherosclerosis imaging-quantitative computed tomography was performed for total plaque volume (TPV) and percentage atheroma volume, as well as the volume of noncalcified plaque (NCP), calcified plaque, and low-density NCP (LD-NCP), diameter stenosis, and vascular remodeling. This study also included VF analysis and subcutaneous fat analysis, recording of outer waist circumference, and percentage body fat analysis. RESULTS: The mean age of the patients was 56.1 [SD 8.5] years, and 84.0% were male. Measures of visceral adiposity (mean [SD, Q1-Q3 thresholds]) included estimated body fat, 28.7% (9.0%, 24.1%-33.0%); VF, 169.8 cm2 (92.3, 102.0-219.0 cm2 ); and subcutaneous fat, 223.6 mm2 (114.2, 142.5-288.0 mm2 ). The Spearman correlation coefficients of VF and plaque volume included TPV 0.22 (p = 0.0074), calcified plaque 0.12 (p = 0.62), NCP 0.25 (p = 0.0023), and LD-NCP 0.37 (p < 0.0001). There was a progression of the median coronary plaque volume for each quartile of VF including TPV (Q1: 19.8, Q2: 48.1, Q3: 86.4, and Q4: 136.6 mm3 [p = 0.0098]), NCP (Q1: 15.7, Q2: 35.4, Q3: 86.4, and Q4: 136.6 mm3 [p = 0.0032]), and LD-NCP (Q1: 0.6, Q2: 0.81, Q3: 2.0, and Q4: 5.0 mm3 [p < 0.0001]). CONCLUSIONS: These findings demonstrate progression with regard to VF and TPV, NCP volume, and LD-NCP volume. Notably, there was a progression of VF and amount of LD-NCP, which is known to be high risk for future cardiovascular events. A consistent progression may indicate the future utility of VF in CVD risk stratification.

Novel Matrix Normalization Technique for Accurate LC-ESI-MS/MS Detection and Quantification of Drugs and Their Metabolites in Toxicology Research and Practice.

Accurate identification and quantification of drugs and their metabolites (analytes) in biological matrices is an analytical foundation of clinical and forensic toxicology. For decades, liquid chromatography interfaced by electrospray ionization with tandem mass spectrometry (LC-ESI-MS/MS) has been a widely used technology for analysis in the field of toxicology, as well as in many other fields of bioscience. It is also known that ion response in LC-ESI-MS/MS analysis is influenced by coeluting biological compounds and that preanalytical sample clean-up is often insufficient in removing these interferences. As a result, a normalization technique is commonly used for assessment and compensation of matrix effects encountered in routine analysis. Internal standardization with a stable isotope analog of the analyte is the predominant normalization technique used in LC-ESI-MS/MS analysis. The technique, however, requires commercial availability or costly custom synthesis of an isotopic analog specific for each analyte. Here we describe an alternative technique for matrix normalization for use in high-volume, multianalyte testing without the need for isotope analogs. The technique involves analysis of the original sample (neat analysis) followed by analysis of a second sample aliquot (spike analysis) that has been fortified with a controlled amount of reference analyte. A calibration procedure similar to internal standardization is employed, using an ion response ratio of neat to fortified analyte. As a demonstration of the technique in multianalyte testing, we provide a detailed protocol for simultaneous detection and quantification of 102 drugs and drug metabolites in human urine. We also provide a support protocol for addition of new analytes to the multianalyte panel, allowing convenient collection of the validation data during routine testing. The matrix normalization technique and testing principles may be applicable to a wide range of analytes and biological matrices, not only those encountered in toxicology but also in other fields of bioscience. © 2023 Wiley Periodicals LLC. Basic Protocol: Detection and quantification of 102 toxicology analytes in urine by LC-ESI-MS/MS analysis using the threshold accurate calibration technique Support Protocol: Method for addition and validation of new analytes to expand the Basic Protocol.

Coronary Artery Calcium Dispersion and Cause-Specific Mortality.

Coronary artery calcium (CAC) measures subclinical atherosclerosis and improves risk stratification. CAC characteristics-including vessel(s) involved, number of vessels, volume, and density-have been shown to differentially impact risk. We assessed how dispersion-either the number of calcified vessels or CAC phenotype (diffuse, normal, and concentrated)-impacted cause-specific mortality. The CAC Consortium is a retrospective cohort of 66,636 participants without coronary heart disease (CHD) who underwent CAC scoring. This study included patients with CAC >0 (n = 28,147). CAC area, CAC density, and CAC phenotypes (derived from the index of diffusion = 1 - [CAC in most concentrated vessel/total Agatston score]) were calculated. The associations between CAC characteristics and cause-specific mortality were assessed. The participant details included (n = 28,147): mean age 58.3 years, 25% female, 89.6% White, and 66% had 2+ calcified vessels. Diabetes, hypertension, and hyperlipidemia were predictors of multivessel involvement (p <0.001). After controlling for the overall CAC score, those with 4-vessel CAC involvement had more CAC area and less dense calcifications than those with 1-vessel. There was a graded increase in all-cause and cardiovascular disease (CVD)- and CHD-specific mortality as the number of calcified vessels increased. Among those with ≥2 vessels involved (n = 18,516), a diffuse phenotype was associated with a higher CVD-specific mortality and had a trend toward higher all-cause and CHD-specific mortality than a concentrated CAC phenotype. Diffuse CAC involvement was characterized by less dense calcification, more CAC area, multiple coronary vessel involvement, and presence of certain traditional risk factors. There is a graded increase in all-cause and CVD- and CHD-specific mortality with increasing CAC dispersion.

Thoracic Aortic Calcium Density and Area in Long-Term Atherosclerotic Cardiovascular Disease Risk Among Men Versus Women.

BACKGROUND: The development of thoracic aortic calcium (TAC) temporally precedes coronary artery calcium more often in women versus men. Whether TAC density and area confer sex-specific differences in atherosclerotic cardiovascular disease (ASCVD) risk is unknown. METHODS: We studied 5317 primary prevention patients who underwent coronary artery calcium scoring on noncontrast cardiac gated computed tomography with TAC >0. The Agatston TAC score (Agatston units), density (Hounsfield units), and area (mm2) were compared between men and women. Cox proportional hazards regression calculated adjusted hazard ratios for TAC density-area groups with ASCVD mortality, adjusting for traditional risk factors, coronary artery calcium, and TAC. Multinomial logistic regression calculated adjusted odds ratios for the association between traditional risk factors and TAC density-area groups. RESULTS: The mean age was 60.7 years, 38% were women, and 163 ASCVD deaths occurred over a median of 11.7-year follow-up. Women had higher median TAC scores (97 versus 84 Agatston units; P=0.004), density (223 versus 210 Hounsfield units; P<0.001), and area (37 versus 32 mm2; P=0.006) compared with men. There was a stepwise higher incidence of ASCVD deaths across increasing TAC density-area groups in men though women with low TAC density relative to TAC area (3.6 per 1000 person-years) had survival probability commensurate with the high-density-high-area group (4.8 per 1000 person-years). Compared with low TAC density-area, low TAC density/high TAC area conferred a 3.75-fold higher risk of ASCVD mortality in women (adjusted hazard ratio, 3.75 [95% CI, 1.13-12.44]) but not in men (adjusted hazard ratio, 1.16 [95% CI, 0.48-2.84]). Risk factors most strongly associated with low TAC density/high TAC area differed in women (diabetes: adjusted odds ratio, 2.61 [95% CI, 1.34-5.07]) versus men (hypertension: adjusted odds ratio, 1.45 [95% CI, 1.11-1.90]). CONCLUSIONS: TAC density-area phenotypes do not consistently associate with ASCVD mortality though low TAC density relative to area may be a marker of increased ASCVD risk in women.

Mortality impact of low CAC density predominantly occurs in early atherosclerosis: explainable ML in the CAC consortium.

BACKGROUND: Machine learning (ML) models of risk prediction with coronary artery calcium (CAC) and CAC characteristics exhibit high performance, but are not inherently interpretable. OBJECTIVES: To determine the direction and magnitude of impact of CAC characteristics on 10-year all-cause mortality (ACM) with explainable ML. METHODS: We analyzed asymptomatic subjects in the CAC consortium. We trained ML models on 80% and tested on 20% of the data with XGBoost, using clinical characteristics â€‹+ â€‹CAC (ML 1) and additional CAC characteristics of CAC density and number of calcified vessels (ML 2). We applied SHAP, an explainable ML tool, to explore the relationship of CAC and CAC characteristics with 10-year all-cause and CV mortality. RESULTS: 2376 deaths occurred among 63,215 patients [68% male, median age 54 (IQR 47-61), CAC 3 (IQR 0-94.3)]. ML2 was similar to ML1 to predict all-cause mortality (Area Under the Curve (AUC) 0.819 vs 0.821, p â€‹= â€‹0.23), but superior for CV mortality (0.847 vs 0.845, p â€‹= â€‹0.03). Low CAC density increased mortality impact, particularly ≤0.75. Very low CAC density ≤0.75 was present in only 4.3% of the patients with measurable density, and 75% occurred in CAC1-100. The number of diseased vessels did not increase mortality overall when simultaneously accounting for CAC and CAC density. CONCLUSION: CAC density contributes to mortality risk primarily when it is very low ≤0.75, which is primarily observed in CAC 1-100. CAC and CAC density are more important for mortality prediction than the number of diseased vessels, and improve prediction of CV but not all-cause mortality. Explainable ML techniques are useful to describe granular relationships in otherwise opaque prediction models.

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.

Distribution of Coronary Artery Calcium by Age, Sex, and Race Among Patients 30-45 Years Old.

BACKGROUND: Coronary artery calcium (CAC) is a measure of atherosclerotic burden and is well-validated for risk stratification in middle- to older-aged adults. Few studies have investigated CAC in younger adults, and there is no calculator for determining age-, sex-, and race-based percentiles among individuals aged <45 years. OBJECTIVES: The purpose of this study was to determine the probability of CAC >0 and develop age-sex-race percentiles for U.S. adults aged 30-45 years. METHODS: We harmonized 3 datasets-CARDIA (Coronary Artery Risk Development in Young Adults), the CAC Consortium, and the Walter Reed Cohort-to study CAC in 19,725 asymptomatic Black and White individuals aged 30-45 years without known atherosclerotic cardiovascular disease. After weighting each cohort equally, the probability of CAC >0 and age-sex-race percentiles of CAC distributions were estimated using nonparametric techniques. RESULTS: The prevalence of CAC >0 was 26% among White males, 16% among Black males, 10% among White females, and 7% among Black females. CAC >0 automatically placed all females at >90th percentile. CAC >0 placed White males at the 90th percentile at age 34 years compared with Black males at age 37 years. An interactive webpage allows one to enter an age, sex, race, and CAC score to obtain the corresponding estimated percentile. CONCLUSIONS: In a large cohort of U.S. adults aged 30-45 years without symptomatic atherosclerotic cardiovascular disease, the probability of CAC >0 varied by age, sex, and race. Estimated percentiles may help interpretation of CAC scores among young adults relative to their age-sex-race matched peers and can henceforth be included in CAC score reporting.

Discordance Between Coronary Artery Calcium Area and Density Predicts Long-Term Atherosclerotic Cardiovascular Disease Risk.

BACKGROUND: Coronary artery calcium (CAC) is commonly quantified as the product of 2 generally correlated measures: plaque area and calcium density. OBJECTIVES: The authors sought to determine whether discordance between calcium area and density has long-term prognostic importance in atherosclerotic cardiovascular disease (ASCVD) risk. METHODS: The authors studied 10,373 primary prevention participants from the CAC Consortium with CAC >0. Based on their median values, calcium area and mean calcium density were divided into 4 mutually exclusive concordant/discordant groups. Cox proportional hazards regression assessed the association of calcium area/density groups with ASCVD mortality over a median of 11.7 years, adjusting for traditional risk factors and the Agatston CAC score. RESULTS: The mean age was 56.7 years, and 24% were female. The prevalence of plaque discordance was 19% (9% low calcium area/high calcium density, 10% high calcium area/low calcium density). Female sex (odds ratio [OR]: 1.48 [95% CI: 1.27-1.74]) and body mass index (OR: 0.81 [95% CI: 0.76-0.87], per 5 kg/m2 higher) were significantly associated with high calcium density discordance, whereas diabetes (OR: 2.23 [95% CI: 1.85-3.19]) was most strongly associated with discordantly low calcium density. Compared to those with low calcium area/low calcium density, individuals with low calcium area/high calcium density had a 71% lower risk of ASCVD death (HR: 0.29 [95% CI: 0.09-0.95]). CONCLUSIONS: For a given CAC score, high calcium density relative to plaque area confers lower long-term ASCVD risk, likely serving as an imaging marker of biological resilience for lesion vulnerability. Additional research is needed to define a robust definition of calcium area/density discordance for routine clinical risk prediction.

Association between hypercholesterolemia and mortality risk among patients referred for cardiac imaging test: Evidence of a "cholesterol paradox?"

AIM: Some observational studies have observed a lower, rather than higher, mortality rate in association with hypercholesterolemia during follow-up of patients after cardiac stress testing. We aim to assess the relationship of hypercholesterolemia and other CAD risk factors to mortality across a wide spectrum of patients referred for various cardiac tests. METHODS AND RESULTS: We identified four cardiac cohorts: 64,357 patients undergoing coronary artery calcium (CAC) scanning, 10,814 patients undergoing coronary CT angiography (CCTA), 31,411 patients without known CAD undergoing stress/rest single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI), and 5051 patients with known CAD undergoing stress/rest SPECT-MPI. Each cohort was followed for all-cause mortality using risk-adjusted Cox models. We pooled the hazard ratios between cohorts with a random effects model. Baseline risk varied markedly among cohorts, from an annualized mortality rate of 0.31%/year in CAC patients to 3.63%/year among SPECT-MPI patients with known CAD. Hypertension, diabetes, and smoking were each associated with increased mortality in each patient cohort (pooled hazard ratio[95% CI]: 1.38[1.33-1.44], 1.88[1.76-2.00], and 1.67[1.48-1.86], respectively). By contrast, hypercholesterolemia was associated with decreased rather than increased mortality (pooled hazard ratio[95% CI]: 0.71[0.58-0.84]). Analysis of serum lipids among 7744 patients undergoing CAC or CCTA scanning revealed an inverse relationship between LDL cholesterol and mortality. CONCLUSIONS: Among a broad spectrum of patients referred for a variety of cardiac tests and ranging from low to high clinical risk, hypercholesterolemia was not associated with increased mortality risk. Our findings suggest that hypercholesterolemia may be sensitive to confounding by other clinical factors and post-test treatment changes in patient populations.

Mean Versus Peak Coronary Calcium Density on Non-Contrast CT: Calcium Scoring and ASCVD Risk Prediction.

OBJECTIVES: This study sought to assess the relationship between mean vs peak calcified plaque density and their impact on calculating coronary artery calcium (CAC) scores and to compare the corresponding differential prediction of atherosclerotic cardiovascular disease (ASCVD) and coronary heart disease (CHD) mortality. BACKGROUND: The Agatston CAC score is quantified per lesion as the product of plaque area and a 4-level categorical peak calcium density factor. However, mean calcium density may more accurately measure the heterogenous mixture of lipid-rich, fibrous, and calcified plaque reflective of ASCVD risk. METHODS: We included 10,373 individuals from the CAC Consortium who had CAC >0 and per-vessel measurements of peak calcium density factor and mean calcium density. Area under the curve and continuous net reclassification improvement analyses were performed for CHD and ASCVD mortality to compare the predictive abilities of mean calcium density vs peak calcium density factor when calculating the Agatston CAC score. RESULTS: Participants were on average 53.4 years of age, 24.4% were women, and the median CAC score was 68 Agatston units. The average values for mean calcium density and peak calcium density factor were 210 ± 50 HU and 3.1 ± 0.5, respectively. Individuals younger than 50 years of age and/or those with a total plaque area <100 mm2 had the largest differences between the peak and mean density measures. Among persons with CAC 1-99, the use of mean calcium density resulted in a larger improvement in ASCVD mortality net reclassification improvement (NRI) (NRI = 0.49; P < 0.001 vs. NRI = 0.18; P = 0.08) and CHD mortality discrimination (Δ area under the curve (AUC) = +0.169 vs +0.036; P < 0.001) compared with peak calcium density factor. Neither peak nor mean calcium density improved mortality prediction at CAC scores >100. CONCLUSION: Mean and peak calcium density may differentially describe plaque composition early in the atherosclerotic process. Mean calcium density performs better than peak calcium density factor when combined with plaque area for ASCVD mortality prediction among persons with Agatston CAC 1-99.

Coronary Artery Calcium for Risk Stratification of Sudden Cardiac Death: The Coronary Artery Calcium Consortium.

BACKGROUND: Coronary artery calcium (CAC) is a marker of plaque burden. Whether CAC improves risk stratification for incident sudden cardiac death (SCD) beyond atherosclerotic cardiovascular disease (ASCVD) risk factors is unknown. OBJECTIVES: SCD is a common initial manifestation of coronary heart disease (CHD); however, SCD risk prediction remains elusive. METHODS: The authors studied 66,636 primary prevention patients from the CAC Consortium. Multivariable competing risks regression and C-statistics were used to assess the association between CAC and SCD, adjusting for demographics and traditional risk factors. RESULTS: The mean age was 54.4 years, 33% were women, 11% were of non-White ethnicity, and 55% had CAC >0. A total of 211 SCD events (0.3%) were observed during a median follow-up of 10.6 years, 91% occurring among those with baseline CAC >0. Compared with CAC = 0, there was a stepwise higher risk (P trend < 0.001) in SCD for CAC 100 to 399 (subdistribution hazard ratio [SHR]: 2.8; 95% CI: 1.6-5.0), CAC 400 to 999 (SHR: 4.0; 95% CI: 2.2-7.3), and CAC >1,000 (SHR: 4.9; 95% CI: 2.6-9.9). CAC provided incremental improvements in the C-statistic for the prediction of SCD among individuals with a 10-year risk <7.5% (ΔC-statistic = +0.046; P = 0.02) and 7.5% to 20% (ΔC-statistic = +0.069; P = 0.003), which were larger when compared with persons with a 10-year risk >20% (ΔC-statistic = +0.01; P = 0.54). CONCLUSIONS: Higher CAC burden strongly associates with incident SCD beyond traditional risk factors, particularly among primary prevention patients with low-intermediate risk. SCD risk stratification can be useful in the early stages of CHD through the measurement of CAC, identifying patients most likely to benefit from further downstream testing.

Matrix Normalization Techniques for Definitive Urine Drug Testing.

Analytical performance of stable isotope-labeled internal standardization (SIL-IS) and threshold accurate calibration (TAC) methods of matrix normalization are compared for quantitation of 51 drugs and metabolites (analytes) in urine with analysis by ultra performance liquid chromatography with tandem mass spectrometry (UPLC-MS-MS). Two SIL-IS methods of analysis were performed, one method using analyte-specific internal standardization (ASIL-IS) and another method using a shared stable isotope from another analyte for internal standardization (SSIL-IS). Variance in inter-specimen matrix effect, without the use of a matrix normalization method, was studied by UPLC-MS-MS analysis of 338 urine donor samples and showed >200% variation in ion response for some analytes. Matrix normalization methods were evaluated for precision, accuracy, calibration, multi-matrix recovery and positive casework quantitation. Acceptable calibration and quality control criteria were achieved for all methods when calibrators and controls were prepared from the same urine matrix pool. Quantitative accuracy, determined by the addition of analytes to multi-donor urine pools at two concentration levels, resulted in acceptable percent relative standard deviation (%RSD) and bias for TAC and ASIL-IS methods. SSIL-IS method quantitations in analyte-supplemented donor pools revealed a %RSD ranging from 20% to 60% for >30% of the analytes and a method bias that ranged up to 87%, with a differential matrix effect on analyte and shared internal standard accounting for the imprecision and bias. Analyte quantitation in 162 authentic case samples showed close agreement for TAC and ASIL-IS methods, with greater variance in the SSIL-IS method. The study demonstrates effective matrix normalization by ASIL-IS and TAC methods and a matrix-caused bias in the SSIL-IS method.