Absence Of Coronary Artery Calcium Research Articles

Incidental Coronary Artery Calcium on Radiation Simulation Scans Identifies Patients for Preventive Therapy

Coronary artery calcium (CAC) is a well-studied marker of atherosclerosis, or coronary artery disease (CAD). A CAC score >0 is associated with increased cardiac-related mortality and may be an indication to initiate statin therapy resulting in fewer cardiac-related adverse events. CAC is well visualized on non-contrast chest CT simulation (sim) scans used for breast radiation (RT) planning. Often this is the only chest CT these patients have ever obtained, and the images are not accessible by other specialists, thus radiation oncologists (ROs) have the opportunity to identify and act upon incidental CAC. We hypothesize that by screening for incidental CAC on CT sims, ROs could help identify patients who should discuss preventive medical interventions (i.e. statin therapy or aspirin) with their primary doctors (PCP) or cardiologists, thus improving overall patient survival. A retrospective analysis of all breast patients treated with external beam RT from January 2017 to December 2018 at a single institution was performed. Patient history, cholesterol, medications, CT sim scans, and RT details were collected and reviewed. Each patient’s 10-year risk of atherosclerotic cardiovascular disease (ASCVD) (heart disease or stroke) was calculated using the online ASCVD Risk Estimator published in the 2013 ACC/AHA Guideline on the Assessment of Cardiovascular Risk. CT sim scans were reviewed for the presence or absence of CAC. Per well-established guidelines, any patient with CAC>0 was identified as being considered for statin therapy. There were 126 breast cancer patients identified: 100% had PCPs, median age 65 [36-87], 88% White, and 91% Stage 0-II breast cancer. Out of 12 patients with known CAD, all were confirmed to have CAC>0, and only 2(16%) were not on statin therapy. From the 114 without a prior history of CAD, 60 (53%) had CAC >0 of which 33 (55%) were not already on recommended statin therapy. Out of 95 patients for whom complete cholesterol data were available, 62 had CAC >0, of which even 44% of patients with a >20% 10-year risk of ASCVD were not on recommended statin therapy. Even in our limited cohort of breast patients who all had access to primary care, the CT sim revealed incidental CAC in >50% of patients of whom >50% were not already on recommended life-saving statin therapy. Similar to additional workup ordered for incidental thyroid and lung nodules visualized on CT sims, our study's findings reveal a significant opportunity for ROs to act from a preventive medicine position. We encourage and recommend ROs to increase attention and reporting of incidental CAC >0 to the patient, PCP or Cardiologist that can help guide cardiac-related preventative strategies, such as medication or lifestyle changes, that could have a profound effect on improving long-term survival in a large group of patients.Abstract 2087; Table 1ASCVD RiskCAC>0On StatinNot on Statin (%)<5%11110 (91%)5-20%19145 (26%)>20%321814 (44%)Total623329 (47%) Open table in a new tab

Point of Care Clinical Risk Score to Improve the Negative Diagnostic Utility of an Agatston Score of Zero: Averting the Need for Coronary Computed Tomography Angiography.

Coronary artery calcification is a marker of underlying atherosclerotic vascular disease. The absence of coronary artery calcification is associated with a low prevalence of obstructive coronary artery disease (CAD), but it cannot be ruled out completely. We sought to develop a clinical tool that can be added to Agatston score of zero to rule out obstructive CAD with high accuracy. We developed a clinical score retrospectively from a cohort of 4903 consecutive patients with an Agatston score of zero. Patients with prior diagnosis of CAD, coronary percutaneous coronary intervention, or surgical revascularization were excluded. Obstructive CAD was defined as any epicardial vessel diameter narrowing of ≥50%. The score was validated using an external cohort of 4290 patients with an Agatston score of zero from a multinational registry. The score consisted of 7 variables: age, sex, typical chest pain, dyslipidemia, hypertension, family history, and diabetes mellitus. The model was robust with an area under the curve of 0.70 (95% CI, 0.65-0.76) in the derivation cohort and 0.69 (95% CI, 0.65-0.72) in the validation cohort. Patients were divided into 3 risk groups based on the score: low (≤6), intermediate (7-13), and high (≥14). Patients who score ≤6 have a negative likelihood ratio of 0.42 for obstructive CAD, whereas those who score ≥14 have a positive likelihood ratio of >5.5 for obstructive CAD. The outcome was ruled out in >98% of patients with a score ≤6 in the validation cohort. We developed a score that may be used to identify the likelihood of obstructive CAD in patients with an Agatston score of zero, which may be used to direct the need for additional testing. However, the results of this retrospective analysis are hypothesis generating and before clinical implementation should be validated in a trial with a prospectively collected data.

Coronary CT Calcium Score in Patients With Prior Nongated CT, Is it Necessary?

PurposeTo evaluate the percentage of patients undergoing gated coronary artery calcium score CTs that had a prior nongated chest CT. To assess the accuracy of prior nongated chest CTs in the detection of coronary calcium. BackgroundCardiovascular disease is the most common cause of death worldwide. Quantifying coronary artery calcification on gated calcium score CT has proven to be strongly predictive of adverse coronary artery disease events. However, visual estimation and ordinal scoring on nongated chest CTs is predictive of coronary calcium burden. MethodsConsecutive gated calcium score CTs at a single institution from 10/2014 to 10/2016 were retrospectively evaluated with IRB approval/waiver of informed consent. The presence or absence of coronary calcium and ordinal score on nongated chest CT was compared to Agatston score on gated calcium score CT. ResultsForty-two of 441 patients (9.5%) with a gated calcium score had a prior nongated chest CT, with a mean time difference of 810 days. Of the 42 prior chest CTs, 69% had coronary artery calcium (CAC) and 31% did not, with 100% predictive accuracy for the presence or absence of CAC on subsequent gated calcium score CTs. There was 86% correlation of Agatston score on gated calcium score CT with ordinal score on the prior chest CT. Ordinal score divided into independent groups of severity was related to increased severity of Agatston score on the gated calcium score CT (P< 0.001). A majority of prior chest CT studies with coronary calcium failed to include this information in the final report. ConclusionsA large percentage of gated calcium score CTs were performed despite a prior chest CT. The ordinal score on chest CTs correlated with Agatston score on gated calcium score CTs. The presence of CAC on chest CTs was underreported in a majority of cases.

Low short-term and long-term cardiovascular and all-cause mortality in absence of coronary artery calcium: A 22-year follow-up observational study from large cohort

ObjectivesWe sought to evaluate the gender-specific predictive value of coronary artery calcium (CAC) score on all-cause mortality and cardiovascular disease (CVD) mortality in individuals with and without diabetes mellitus (DM). BackgroundCAC score is a robust predictor of CVD and all-cause mortality during long-term follow-up in large cohorts in adults with DM. However, less is known about its sex-specific impact on all-cause mortality in DM. MethodsWe evaluated 25,563 asymptomatic participants with no known history of coronary artery disease (CAD) who underwent clinically indicated CAC. 1999 (7.8%) individuals had diabetes. CAC was characterized as an Agatston score of 0, 1–99, 100–300, and ≫300. We evaluated the association between CAC and all-cause mortality and CVD mortality. ResultsOverall, 1345 individuals died (5.3%) from all causes during a mean follow-up of 14.7 ± 3.8 years. CAC score was 0 in 57.5% females and 34.4% of males without DM, while 36.6% females and 20.3% males with DM had CAC-0. The frequency of CAC ≫ 300 was 18% and 36% in females and males with DM, respectively. CAC score of zero was associated with low all-cause mortality event rate in females and males with diabetes (1.7 and 2.5 events per 1000 person-years, respectively). Cardiovascular mortality per 1000 person years was ≪1 in females and males with CAC score of 0 irrespective of their diabetes. Adjusted multivariable analysis, compared to CAC-0, HR for all-cause mortality associated with CAC 1–99, 100–299 and ≫300 were 1.74(95% CI 0.65, 4.63, P-0.20), 5.54(95% CI 2.16, 14.22, P ≪ 0.001) and 5.75(95% CI 2.30, 14.37, P ≪ 0.001) in females with DM respectively; in males with DM HR associated with CAC 1–99, 100–299 and ≫300 were 1.87(95% CI 0.95, 3.66, P-0.06), 2.15(95% CI 1.05, 4.38, P-0.035) and 2.60(95% CI 1.34, 5.0, P-0.004), respectively. ConclusionPresence of subclinical atherosclerosis varies among individuals with DM. The absence of CAC was associated with very low cardiovascular as well as all-cause mortality events in all subgroups during long term follow-up.

Implications of coronary artery calcium testing on risk stratification for lipid-lowering therapy according to the 2016 European Society of Cardiology recommendations: The MESA study.

The European Society of Cardiology (ESC) guideline on cardiovascular risk assessment considers coronary artery calcium a class B indication for risk assessment. We evaluated the degree to which coronary artery calcium can change the recommendation for individuals based on a change in estimated risk. We stratified 5602 MESA participants according to the ESC recommendation as: no lipid-lowering treatment recommended ( N = 2228), consider lipid-lowering treatment if uncontrolled ( N = 1686), or lipid-lowering treatment recommended ( N = 1688). We evaluated the ability of coronary artery calcium to reclassify cardiovascular risk. Among the selected sample, 54% had coronary artery calcium of zero, 25% had coronary artery calcium of 1-100 and 21% had coronary artery calcium greater than 100. In the lipid-lowering treatment recommended group 31% had coronary artery calcium of zero, while in the lipid-lowering treatment if uncontrolled group about 50% had coronary artery calcium of zero. The cardiovascular mortality rate was 1.7%/10 years in the lipid-lowering treatment if uncontrolled, and 7.0%/10 years in the lipid-lowering treatment recommended group. The absence of coronary artery calcium was associated with 1.4%/10 years in the lipid-lowering treatment if uncontrolled group and 3.0%/10 years in the lipid-lowering treatment recommended group. Compared with coronary artery calcium of zero, any coronary artery calcium was associated with significantly higher cardiovascular mortality in the lipid-lowering treatment recommended group (9.0%/10 years), whereas only coronary artery calcium greater than 100 was significantly associated with a higher cardiovascular mortality in the lipid-lowering treatment if uncontrolled group (3.2%/10 years). The absence of coronary artery calcium is associated with a low incidence of cardiovascular mortality or coronary heart disease events even in individuals in whom lipid-lowering therapy is recommended. A significant proportion of individuals deemed to be candidates for lipid-lowering therapy might be reclassified to a lower risk group with the use of coronary artery calcium.

THE WARRANTY PERIOD FOLLOWING A CORONARY ARTERY CALCIUM SCORE OF ZERO: THE WALTER REED COHORT

The absence of coronary artery calcium (CAC) has been shown to be a strong negative risk factor for cardiovascular events; though, there is limited data on the optimal time interval for re-assessing for development of CAC on future scans. A previous study suggested that patients rarely convert from

ABSENCE OF VISUAL CORONARY ARTERY CALCIUM ON LOW DOSE ATTENUATION CT DURING PET/CT PREDICTS VERY LOW INCIDENCE OF REVASCULARIZATION AND MACE

Absence of coronary artery calcium (CAC) is known to predict low risk of subsequent major adverse coronary artery events (MACE). However, little is known about its ability in symptomatic patients (pts) undergoing stress testing to predict using CAC subsequent coronary revascularization (Revasc) and

Primary prevention of coronary artery disease: let's start with calcium score.

Primary prevention of coronary artery disease: let's start with calcium score.

2311

OBJECTIVES/SPECIFIC AIMS: Cardiac complications are common after hospital admission for sepsis, and elevated troponin has been associated with increased all-cause mortality. However, little is known about clinical or imaging factors that predict these cardiac events. Coronary artery calcification (CAC) is an easily identifiable imaging finding, even on nongated CT scans. The goal of this study is to identify if CAC predicts all cause mortality and acute myocardial infarction. METHODS/STUDY POPULATION: This is a single center, nonconcurrent cohort study including 899 patients who were admitted for sepsis and had a detectable TnI level from January 2013 to December 2013. Patients with a CT scan of the chest or abdomen done for other clinical indications within 6 months of this admission were reviewed for the presence or absence of CAC. Medical records were individually reviewed for mortality and type I acute myocardial infarctions at 1 year. RESULTS/ANTICIPATED RESULTS: In total, 144 patients (mean age 57±14.8 years, 48% female) were included in the analysis. CAC was seen in 59% of these scans. Compared to those without detectable CAC, the CAC group had similar APACHE score (18 vs. 16.6, p=0.259), peak TnI (3.64 vs. 2.11 mg/dL, p=0.363), aspirin (63% vs. 51%, p=0.144), and β blocker use (90% vs. 85%, p=0.357) and had higher statin use (48% vs. 27%, p=0.013). CAC was associated with increased all-cause mortality (59.5% vs. 38.9%, p=0.016) and type I myocardial infarctions (10.6% vs. 1.7%, p=0.039) compared with those without CAC. DISCUSSION/SIGNIFICANCE OF IMPACT: Coronary artery calcification is often seen when patients present with a noncardiac acute illness, such as sepsis, often making a new diagnosis for these patients. Mortality and acute MI after sepsis can be predicted by coronary calcification, and identify patients who should be targeted for therapy and close follow-up.

Visual Estimation of Coronary Artery Calcium and the Effect of the Absence of Coronary Artery Calcium on Cardiac Events and the Interpretation of Myocardial Perfusion in Hybrid SPECT/CT Scans

The use of visual estimation of coronary artery calcium (CAC) on hybrid SPECT/CT imaging can be to provide additional source of information to assist in the interpretation of borderline myocardial perfusion images (MPI). We assessed the effect of the absence of CAC on cardiac events and the interpretation of non extensive perfusion defects. Background: At the time of MPI, hybrid systems obtain a low dose, non-ECG-gated CT scan that is used to perform attenuation correction. The utility of visual coronary CT attenuation correction scan (CTAC) in estimating actual CAC as measured by the Shemesh score (SS) was also validated. Methods: At our hospital two experienced readers, blinded to CAC scores, classified 150 patients using visual estimation of the SS. Each of the four main coronary arteries (left main, left anterior descending, left circumflex and right coronary artery) were scored 0 to 3. Calcification scoring was as follows: none (0); mild (1), when less than 1/3 of the length of the entire artery was calcified; moderate (2), when 1/3 to 2/3 of the artery was calcified; and severe (3), when more than 2/3 of the artery showed calcification. The scores for the four arteries were added to produce the total SS (0-12). To assess the effect of absence of calcium on interpretation of MPI scans we measured the size of the perfusion defect using the sum stress score (SSS) in a 17 segment model. Six month phone interviews for cardiac events was conducted at six months on 30/150 patients whose CAC score was read as zero. Results: Visual assessment of CAC had a excellent intraclass correlation coefficient of 0.973 for total calcium score, with 95% confidence interval of 0.963 to 0.980. 20% (30/150) patients had a CAC score read as zero. 97% (29/30) MPI scans read with a CAC score of zero were also read as having no inducible myocardial perfusion abnormality despite 70% (21/30) having a abnormal SSS. 10% (3/30) patients had normal coronary angiography. No patient (0/30) had a cardiac event at six months whose CAC Score was read as zero. Conclusion: CAC can be visually estimated from a CTAC scan with high degree of inter-observer reproducibility. Absence of CAC influences the interpretation of borderline MPI and may better define the risk of cardiac events during follow-up.

Using coronary calcification to exclude an ischemic etiology for cardiomyopathy: A validation study and systematic review

BackgroundPreliminary data suggests the absence of coronary artery calcification (CAC) excludes ischemic etiologies of cardiomyopathy. We prospectively validate and perform a systematic review to determine the utility of an Agatston score=0 to exclude the diagnosis of ischemic cardiomyopathy. Methods and resultsPatients with newly diagnosed LV dysfunction were prospectively enrolled. Patients underwent CAC imaging and were followed until an etiologic diagnosis of cardiomyopathy was made. Eighty-two patients were enrolled in the study and underwent CAC imaging with 81.7% patients having non-ischemic cardiomyopathy. An Agatston score=0 successfully excluded an ischemic etiology for cardiomyopathy with a specificity of 100% (CI: 74.7–100%) and a positive predictive value of 100% (CI: 85.0%–100%).A systematic literature review was performed and studies were deemed suitable for inclusion if: 1) patients with CHF, cardiomyopathy or LV dysfunction were enrolled, 2) underwent CAC imaging and patients were assessed for an Agatston score=0 or the absence of CAC, and 3) the final etiologic diagnosis (ischemic or non-ischemic) was provided. Eight studies provided sufficient information to calculate operating characteristics for an Agatston score=0 and were combined with our validation cohort for a total of 754 patients. An Agatston score=0 excluded ischemic cardiomyopathy with specificity and positive predictive values of 98.4% (CI: 95.6–99.5%), and 98.3% (CI: 95.5–99.5%), respectively. ConclusionsIn patients with cardiomyopathy of unknown etiology, an Agatston score=0 appears to rule out an ischemic etiology. A screening CAC may be a simple and cost-effective method of triaging patients, identifying those who do and do not need additional CAD investigations.

Prevalence and Prognostic Implications of Coronary Artery Calcification in Low-Risk Women

The role of coronary artery calcium (CAC) testing for guiding preventive strategies among women at low cardiovascular disease (CVD) risk based on the American College of Cardiology and American Heart Association CVD prevention guidelines is unclear. To assess the potential utility of CAC testing for CVD risk estimation and stratification among low-risk women. Women with 10-year atherosclerotic CVD (ASCVD) risk lower than 7.5% from 5 large population-based cohorts: the Dallas Heart Study (United States), the Framingham Heart Study (United States), the Heinz Nixdorf Recall study (Germany), the Multi-Ethnic Study of Atherosclerosis (United States), and the Rotterdam Study (the Netherlands). The 5 cohorts were selected based on the availability of CAC data in a sizable group of low-risk women from the general population together with the long detailed follow-up data. Across the cohorts, events were assessed from the date of CAC scan (performed from 1998 through 2006) until January 1, 2012; January 1, 2014; or March 6, 2015. Fixed-effects meta-analysis was conducted to combine the results of the 5 studies. CAC score by computed tomography. Main outcome was incident ASCVD, including nonfatal myocardial infarction, coronary heart disease (CHD) death, and stroke. Association of CAC with ASCVD was examined using Cox proportional hazards models. To assess whether CAC was associated with improved ASCVD risk predictions beyond the traditional risk factors, the C statistic and the continuous net reclassification improvement (cNRI) index were calculated. Among 6739 women with low ASCVD risk from the 5 studies, mean age ranged from 44 to 63 years and CAC was present in 36.1%. Across the cohorts, median follow-up ranged from 7.0 to 11.6 years. A total of 165 ASCVD events occurred (64 nonfatal myocardial infarctions, 29 CHD deaths, and 72 strokes), with the ASCVD incidence rates ranging from 1.5 to 6.0 per 1000 person-years. Compared with the absence of CAC (CAC = 0), presence of CAC (CAC >0) was associated with an increased risk of ASCVD (incidence rates per 1000 person-years, 1.41 for CAC absence vs 4.33 for CAC presence; difference, 2.92 [95% CI, 2.02-3.83]; multivariable-adjusted hazard ratio, 2.04 [95% CI, 1.44-2.90]). The addition of CAC to traditional risk factors improved the C statistic from 0.73 (95% CI, 0.69-0.77) to 0.77 (95% CI, 0.74-0.81) and provided a cNRI of 0.20 (95% CI, 0.09-0.31) for ASCVD prediction. Among women at low ASCVD risk, CAC was present in approximately one-third and was associated with an increased risk of ASCVD and modest improvement in prognostic accuracy compared with traditional risk factors. Further research is needed to assess the clinical utility and cost-effectiveness of this additional accuracy.

Abstract 11370: Coronary Artery Calcium Incidence Varies by ASCVD Risk: Insights From the Dallas Heart Study

Introduction: Absence of coronary artery calcium (CAC=0) is associated with favorable cardiovascular outcomes and can be useful for down-classifying risk in middle-aged asymptomatic individuals. Identifying predictors of incident CAC can inform preventive measures. Hypothesis: We hypothesized that in a young, multi-ethnic, population-based cohort, increasing atherosclerotic cardiovascular disease (ASCVD) risk would be associated with incident CAC on repeat scanning. Methods: Participants of the Dallas Heart Study (DHS) underwent CAC scanning at baseline (EBCT) and at follow up (MDCT), after a mean interval of 6.9 years. Participants with baseline CAC=0 were included, and those with clinical ASCVD or on statin therapy were excluded. Incident CAC was analyzed as CAC &gt;0 as well as CAC &gt;10 at follow up. ASCVD risk was calculated using the 2013 AHA/ACC risk estimator. Results: Among 2,272 participants with baseline and follow up CAC measurements, 756 participants meeting exclusion criteria had absent CAC (CAC=0) at baseline, with a mean age of 42 years, 65.6% women, and 42.2% blacks. Of these individuals, incident CAC occurred in 23.8% using CAC &gt;0 and in 8.3% using CAC &gt;10. Risk markers associated with incident CAC &gt;0 included baseline 10-year ASCVD risk, family history of coronary heart disease, low density lipoprotein particle concentration, diabetes and statin use at follow up. In fully adjusted analyses, only baseline 10-year ASCVD risk was associated with incident CAC &gt;0. The prevalence of CAC &gt;0 at follow up by baseline 10-year ASCVD risk categories of &lt;5%, ≥5 to &lt;7.5%, and &gt;7.5% was 21.2%, 41.5%, and 51.4%, respectively (p-trend&lt;0.01). The prevalence of CAC &gt;10 was 7%, 12.2%, and 27.1% respectively. Conclusions: In this young cohort, one in four individuals with absent CAC developed incident CAC after approximately 7 years. Reassessing risk, including consideration of repeat CAC measurement in those with higher baseline 10-year ASCVD risk, may be warranted.

National trends among radiologists in reporting coronary artery calcium in non-gated chest computed tomography.

Coronary artery calcification (CAC) is a known risk factor for adverse outcomes in the general population and in patients with coronary artery disease. We performed a survey of United States radiologists to evaluate the trends in reporting the presence or absence of CAC on NCCT examinations. An 11 multiple-choice questionnaire was distributed to members of the American College of Radiology, and 530 members participated in the study. Eighty-seven percent of the analyzed group report the presence of CAC on standard CT scans of the chest, and approximately half them (52 %) use a qualitative modifier. Only 32 % of cardiac imagers were aware of the published data correlating qualitative and quantitative calcium scores on non-gated chest CT examinations compared to 17 % of non-cardiac imagers. We believe that subjective or objective grading of coronary calcified plaque burden on standard chest CT exams is warranted as it may not only help risk-stratify patients, but also may eliminate the need for dedicated CACS in many patients and may be useful in treatment guidance.

Absence of Coronary Artery Calcium Identifies Asymptomatic Diabetic Individuals at Low Near-Term But Not Long-Term Risk of Mortality: A 15-Year Follow-Up Study of 9715 Patients.

Data regarding coronary artery calcification (CAC) prognosis in diabetic individuals are limited to 5-years follow-up. We investigated the long-term risk stratification of CAC among diabetic compared with nondiabetic individuals. Nine thousand seven hundred and fifteen asymptomatic individuals undergoing CAC scoring were followed for a median (interquartile range) of 14.7 (13.9-15.6) years. The incidence density rate and hazard ratios with 95% confidence intervals were used to calculate all-cause mortality. Incremental prognostic utility of CAC was evaluated using the area under the receiver operator characteristic curve and net reclassification improvement. Diabetics (54.7±10.8 years; 59.4% male) comprised 8.3% of the cohort (n=810), of which 188 (23.2%) died. For CAC=0, the rate of mortality was similar between diabetic and nondiabetic individuals for the first 5 years (P>0.05), with a nonlinear increased risk of mortality for diabetics after 5 years (P<0.05). The adjusted risk of death for those in the highest (CAC>400) versus the lowest (CAC=0) category of CAC increased by a hazards of 4.64 (95% confidence interval =3.74-5.76) and 3.41 (95% confidence interval =2.22-5.22) for nondiabetic and diabetic individuals, respectively. The presence of CAC improved discrimination (area under the receiver operator characteristic curve range: 0.73-0.74; P<0.01) and reclassification (category-free net reclassification improvement range: 0.53-0.50; P<0.001) beyond conventional risk factors in nondiabetic and diabetic individuals, respectively. CAC=0 is associated with a favorable 5-year prognosis for asymptomatic diabetic and nondiabetic individuals. After 5 years, the risk of mortality increases significantly for diabetic individuals even in the presence of a baseline CAC=0.

Abstract 16212: Warranty Period of Zero Coronary Artery Calcium Score in Asymptomatic Korean Individuals

Introduction: Zero coronary artery calcium (CAC) is a reliable predictor of absent atherosclerosis and serves as a useful adjunct for identifying those at low risk. Despite this, the “warranty period” that displays the protective value associated with the absence of CAC towards experiencing a cardiovascular event among Asians is not well established. Hypothesis: To examine whether the absence of CAC displays a more favorable warranty period for all-cause death compared with the presence of CAC in a Korean cohort. Methods: A total of 48,215 asymptomatic Koreans (mean age: 54±8.8 years; 25% women) were enrolled and stratified by the absence or presence of CAC. Time to exceeding 1% of cumulative all-cause death was estimated in order to identify low-risk individuals. Hazard ratios (HR) with 95% confidence intervals (95% CI) for all-cause death were estimated according to prespecified cardiac risk factors and the presence of CAC. Results: In total, 30,605 (63.5%) individuals presented with a zero CAC. Across a median follow-up of 4.4 years (Interquartile range: 2.7-6.6 years), 415 (0.9%) individuals experienced the endpoint of all-cause death. For those with a zero CAC, the time to exceeding 1% risk was found to be 9 years, indicating a substantially longer warranty period compared with participants with a CAC&gt;0 (e.g., 5 year warranty period). The time to exceeding 1% risk tended to decline for individuals on the background of increasing CAC scores. For each of the other prespecified risk factor groups, a zero CAC provided a longer cumulative event free period than in the presence of any CAC. Cox regression analyses also revealed that the absence of CAC was independently associated with a lower risk of all-cause death in each of the respective risk factor groups when compared with CAC&gt;0. Conclusions: In a large cohort of asymptomatic Korean individuals, the absence of CAC evokes a strong protective effect against all-cause death as demonstrated by a longer warranty period.

Implications of Coronary Artery Calcium Testing Among Statin Candidates According to American College of Cardiology/American Heart Association Cholesterol Management Guidelines: MESA (Multi-Ethnic Study of Atherosclerosis)

BackgroundThe American College of Cardiology (ACC)/American Heart Association (AHA) cholesterol management guidelines have significantly broadened the scope of candidates eligible for statin therapy. ObjectivesThis study evaluated the implications of the absence of coronary artery calcium (CAC) in reclassifying patients from a risk stratum in which statins are recommended to one in which they are not. MethodsMESA (Multi-Ethnic Study of Atherosclerosis) is a longitudinal study of 6,814 men and women 45 to 84 years of age without clinical atherosclerotic cardiovascular disease (ASCVD) risk at enrollment. We excluded 1,100 participants (16%) on lipid-lowering medication, 87 (1.3%) without low-density lipoprotein levels, 26 (0.4%) with missing risk factors for calculation of 10-year risk of ASCVD, 633 (9%) >75 years of age, and 209 (3%) with low-density lipoprotein <70 mg/dl from the analysis. ResultsThe study population consisted of 4,758 participants (age 59 ± 9 years; 47% males). A total of 247 (5.2%) ASCVD and 155 (3.3%) hard coronary heart disease events occurred over a median (interquartile range) follow-up of 10.3 (9.7 to 10.8) years. The new ACC/AHA guidelines recommended 2,377 (50%) MESA participants for moderate- to high-intensity statins; the majority (77%) was eligible because of a 10-year estimated ASCVD risk ≥7.5%. Of those recommended statins, 41% had CAC = 0 and had 5.2 ASCVD events/1,000 person-years. Among 589 participants (12%) considered for moderate-intensity statin, 338 (57%) had a CAC = 0, with an ASCVD event rate of 1.5 per 1,000 person-years. Of participants eligible (recommended or considered) for statins, 44% (1,316 of 2,966) had CAC = 0 at baseline and an observed 10-year ASCVD event rate of 4.2 per 1,000 person-years. ConclusionsSignificant ASCVD risk heterogeneity exists among those eligible for statins according to the new guidelines. The absence of CAC reclassifies approximately one-half of candidates as not eligible for statin therapy.

Coronary artery calcium screening: does it perform better than other cardiovascular risk stratification tools?

Coronary artery calcium (CAC) has been advocated as one of the strongest cardiovascular risk prediction markers. It performs better across a wide range of Framingham risk categories (6%–10% and 10%–20% 10-year risk categories) and also helps in reclassifying the risk of these subjects into either higher or lower risk categories based on CAC scores. It also performs better among population subgroups where Framingham risk score does not perform well, especially young subjects, women, family history of premature coronary artery disease and ethnic differences in coronary risk. The absence of CAC is also associated with excellent prognosis, with 10-year event rate of 1%. Studies have also compared with other commonly used markers of cardiovascular disease risk such as Carotid intima-media thickness and highly sensitive C-reactive protein. CAC also performs better compared with carotid intima-media thickness and highly sensitive C-reactive protein in prediction of coronary heart disease and cardiovascular disease events. CAC scans are associated with relatively low radiation exposure (0.9–1.1 mSv) and provide information that can be used not only for risk stratification but also can be used to track the progression of atherosclerosis and the effects of statins.

Identification of Coronary Artery Calcification and Diagnosis of Coronary Artery Disease by Abdominal CT: A Resident Education Continuous Quality Improvement Project

Coronary artery calcium (CAC) scoring is an excellent imaging tool for subclinical atherosclerosis detection and risk stratification. We hypothesize that although CAC has been underreported in the past on computed tomography (CT) scans of the abdomen, specialized resident educational intervention can improve on this underreporting. Beginning July 2009, a dedicated radiology resident cardiac imaging rotation and curriculum was initiated. A retrospective review of the first 500 abdominal CT reports from January 2009, 2011, and 2013 was performed including studies originally interpreted by a resident and primary attending physician interpretations. Each scan was reevaluated for presence or absence of CAC and coronary artery disease (CAD) by a cardiovascular CT expert reader. These data were then correlated to determine if the presence of CAC had been properly reported initially. The results of the three time periods were compared to assess for improved rates of CAC and CAD reporting after initiation of a resident cardiac imaging curriculum. Statistically significant improvements in the reporting of CAC and CAD on CT scans of the abdomen occurred after the initiation of formal resident cardiac imaging training which included two rotations (4 weeks each) of dedicated cardiac CT and cardiac magnetic resonance imaging interpretation during the resident's second, third, or fourth radiology training years. The improvement was persistent and increased over time, improving from 1% to 72% after 2 years and to 90% after 4 years. This single-center retrospective analysis shows association between implementation of formal cardiac imaging training into radiology resident education and improved CAC detection and CAD reporting on abdominal CT scans.

Cardiovascular lifetime risk predicts incidence of coronary calcification in individuals with low short-term risk: the Dallas Heart Study.

BackgroundThe absence of coronary artery calcium (CAC) in middle age is associated with very low short‐term risk for coronary events. However, the long‐term implications of a CAC score of 0 are uncertain, particularly among individuals with high cardiovascular lifetime risk. We sought to characterize the association between predicted lifetime risk and incident CAC among individuals with low short‐term risk.Methods and ResultsWe included 754 Dallas Heart Study participants with serial CAC scans (6.9 years apart) and both low short‐term risk and baseline CAC=0. Lifetime risk for cardiovascular disease was estimated according to risk factor burden. Among this group, 365 individuals (48.4%) were at low lifetime risk and 389 (51.6%) at high lifetime risk. High lifetime risk was associated with higher annualized CAC incidence (4.2% versus 2.7%; P < 0.001). Similarly, mean follow‐up CAC scores were higher among participants with high lifetime risk (7.8 versus 2.4 Agatston units). After adjustment for age, sex, and race, high lifetime risk remained independently associated with incident CAC (OR 1.60; 95% CI 1.12 to 2.27; P=0.01). When assessing risk factor burden at the follow‐up visit, 66.7% of CAC incidence observed in the low lifetime risk group occurred among individuals reclassified to a higher short‐ or long‐term risk category.ConclusionAmong individuals with low short‐term risk and CAC scores of 0, high lifetime risk is associated with a higher incidence of CAC. These findings highlight the importance of lifetime risk even among individuals with very low short‐term risk.