Coronary Artery Calcium Score Of Zero Research Articles

Coronary Artery Calcium Scoring to Exclude Flow-Limiting Coronary Artery Disease in Symptomatic Stable Patients at Low or Intermediate Risk

To assess the capability of a zero coronary artery calcium (CAC) score to help exclude flow-limiting coronary artery disease (CAD) in a homogeneous population with stable anginal complaints and a low-to-intermediate pretest likelihood. The study protocol had institutional ethics committee approval, with written informed consent from all patients. Between 2009 and 2011, a total of 3501 consecutive stable patients without known CAD underwent prospectively simultaneous myocardial perfusion imaging and CAC scoring on a hybrid, 64-section single photon emission computed tomography (SPECT)/computed tomography (CT) scanner. In 868 (25%) of 3501 patients, the CAC score was zero, and these patients constituted the current study population. When feasible, additional coronary CT angiography was performed in those with abnormal SPECT findings. Clinical follow-up was recorded with regard to invasive coronary angiography, coronary revascularization, nonfatal myocardial infarction, or death. Results were analyzed by using descriptive statistics. In 868 patients (mean age, 54 years ± 11 [standard deviation]; 610 [70%] female, 258 [30%] male), SPECT findings were normal in 766 (88%) and abnormal in 102 (12%), with equivocal results in 41 (5%), persistent defect in 35 (4%), and ischemia in 26 (3%). In the group with abnormal SPECT findings, additional coronary CT angiography was performed in 93 patients (91%), showing nonobstructive CAD in eight patients (9%) and normal coronary arteries in 85 patients (91%). In the other nine patients (9%), invasive angiography was used to exclude obstructive CAD. At a median follow-up of 17 months (25th percentile, 11; 75th percentile, 24 months), no coronary events were recorded. A CAC score of zero in stable patients at low or intermediate risk excludes flow-limiting CAD. These findings support the possibility of CAC scoring as a simple and safe tool to select patients for additional testing or discharge, as recommended in the literature.

Prevalence and Prognostic Implication of Non-Calcified Plaque in Asymptomatic Population with Coronary Artery Calcium Score of Zero

Background and ObjectivesNon-calcified plaque (NCP) identified by coronary CT angiography (CCTA) has been reported in up to 10% of individuals with coronary artery calcium score (CACS) of zero. However, clinical risk factors and the prognostic value of NCP in asymptomatic subjects with CACS of zero are unknown.Subjects and MethodsThe study population consisted of consecutive asymptomatic subjects (48±8 years, 57% men) who underwent CCTA from December 2005 to January 2008 as part of a general health evaluation.ResultsAmong 4491 of overall asymptomatic individuals with CACS of zero, 313 subjects (7%) had NCP: 279 patients (6%) with non-obstructive and 34 (1%) with obstructive. In multivariable analyses, age, male gender, diabetes, hypertension, and dyslipidemia were significantly associated with presence of NCP (all p<0.05). During the median follow-up duration of 22 months (interquartile percentile: 18 to 28 months) of subjects with NCP (n=313) and age, gender, and CCTA date matched individuals without NCP (n=313), there was no clinical event including all-cause death nor composite outcome of cardiac death, myocardial infarct, unstable angina requiring hospitalization, and revascularization after 90 days from index CCTA in both groups.ConclusionIn the largest series of asymptomatic individuals with CACS of zero undergoing CCTA, age, male gender, diabetes, hypertension, and dyslipidemia were independently associated with NCP. However, a future risk of exclusive NCP in asymptomatic subjects with CACS of zero was negligible.

Predictive Factors of the Presence and Number of Noncalcified Coronary Plaque in Japanese Patients with Zero Coronary Artery Calcium Score Using 64-Slice Multi-Detector Computed Tomography

Background: Factors that can predict the presence and number of noncalcified coronary plaques (NCP) in Japanese patients with zero coronary artery calcium scores (CACS) essentially remain undefined. Methods and Results: We assessed independent predictors of the presence and number of segments with NCP in 111 Japanese patients with zero CACS who underwent 64-slice multi-detector computed tomography at our hospital. Thirty five patients (32%) had NCP, and 24 patients (22%) had ≥ 2 NCPs. Multiple logistic regression analysis revealed that significant predictors for the presence of NCP were age (odds ratio [OR]: 1.06, 95% confidence interval [CI] 1.01 - 1.11, p = 0.021), male (OR: 3.61, 95% CI 1.40 - 9.35, p = 0.008) and diabetes mellitus (OR: 3.10, 95% CI 1.02 - 9.45, p = 0.046), and those for the presence of ≥ 2 NCPs were age (OR: 1.08, 95% CI 1.02 - 1.15, p = 0.007) and a current smoking habit (OR: 5.09, 95% CI 1.00 - 25.74, p = 0.049). Multiple linear regression analysis identified advanced age, male gender and diabetes mellitus as independent predictors of the number of NCPs. A novel score calculated from the above four predictors showed moderate accuracy for a diagnosis of NCP and ≥ 2 NCPs, with areas under receiver operating curves of 0.738 and 0.736, respectively. Conclusions: Male Japanese patients with zero CACS, advanced age, diabetes mellitus and a current smoking habit might have NCPs.

Frequency and extent of coronary atherosclerotic plaques in patients with zero coronary artery calcium score: assessment with computed tomographic angiography

We aimed to evaluate the frequency and extent of coronary atherosclerotic plaques in patients with a coronary artery calcium (CAC) score of zero and establish the demographic characteristics and the cardiovascular risk factors that affect the formation of atheromatous plaques. Coronary computed tomography (CT) angiography was performed in 288 cases with a CAC score of zero. The plaques that were detected using coronary CT angiography were categorized into two groups: nonsignificant (<50%) and significant (≥50%). Based on the coronary CT angiography results, the patients who had plaque and those who did not have plaque were compared in terms of the demographic characteristics and the presence of cardiovascular risk factors. Noncalcified plaques were detected in 50 cases (17.4%) on CT angiography, of which six cases (2.1%) had significant stenosis. The plaques were localized most frequently (38.2%) in the proximal left anterior descending artery. When all the plaques considered 50% of the plaques were localized in the proximal segments, 42.7% were in the mid-segments, and 7.3% were in the distal segments. Hypertension was a significant risk factor for coronary artery disease in both genders, and smoking was a significant risk factor in females. Additionally, diabetes mellitus was a borderline significant risk factor in both genders. In patients with a CAC score of zero, the frequency of noncalcified plaques is too high to be ignored. The distribution of these plaques in the coronary artery is similar to calcified plaque localizations. Patients who have a CAC score of zero and cardiovascular risk factors need to be evaluated with additional tests for the detection of noncalcified plaques.

Carotid Intima-Media Thickness and Coronary Artery Calcium Score as Indications of Subclinical Atherosclerosis

To determine the ability of carotid intima-media thickness (CIMT) and coronary artery calcium score (CACS) to detect subclinical atherosclerosis in a young to middle-aged, low-risk, primary-prevention population. Patients aged 36 to 59 years who underwent determination of CIMT and CACS at our institution between May 1, 2004, and April 1, 2008, were included in the study. Those with diabetes mellitus or a history of coronary, peripheral, or cerebral vascular disease were excluded. Other information, such as Framingham risk score (FRS), was obtained by a review of clinical and laboratory data. Of 118 patients, 89 (75%) had a CACS of zero and 94 (80%) were men; mean +/- SD age was 48.9+/-5.7 years. The mean FRS of this group was 4.0; 86 patients (97%) were considered at low risk (<1% annualized rate) of cardiovascular events. Evidence of carotid atherosclerosis was found in 42 (47%; 95% confidence interval, 37%-58%) of these 89 patients; carotid plaque was found in 30 (34%); and CIMT above the 75th percentile was found in 12 (13%) of age-, sex-, and race-matched control patients. Of the 40 patients with low-risk CIMT (below the 50th percentile), 4 (10%) had a CACS at or above the 50th percentile. Subclinical vascular disease can be detected by CIMT evaluation in young to middle-aged patients with a low FRS and a CACS of zero. These findings have important implications for vascular disease screening and the implementation of primary-prevention strategies.

111 Single centre prospective cardiac CT study to determine the prevalence of patients with coronary artery disease with a zero coronary artery calcium score and associated non-cardiac incidental findings

<h3>Introduction</h3> Cardiac CT, incorporating coronary artery calcium (CAC) scoring and angiography, is being increasingly used to evaluate patients with chest pain and exclude coronary artery disease (CAD), as recommended in the recent NICE guidelines. Calcification of the coronary arteries is an excellent marker of underlying atherosclerosis, but a zero CAC score does not completely exclude the diagnosis as potentially significant non-calcified plaques will not be detected by CAC scoring. CT imaging may also identify non-cardiac incidental findings that can lead to further downstream testing and medical expense. <h3>Objectives</h3> (1) To evaluate the probability of CAD in patients with a CAC score of zero. (2) To determine the incidence of non-cardiac incidental findings on cardiac CT and to quantify resulting investigations. <h3>Methods</h3> 116 symptomatic patients undergoing cardiac CT to exclude CAD from November 2009 to October 2010 were prospectively enrolled. Patients underwent CAC scoring and had contrast-enhanced, 128-slice, dual source CT coronary angiography (CTCA―Siemens Flash). Scans were dual-reported by a cardiac radiologist and a cardiologist. Statistical analysis was performed using GraphPadPrism. <h3>Results</h3> 62/116 patients had a CAC score of zero. Of these, 57 (91.9%) patients had normal coronary arteries, 4 (6.5%) patients had non-obstructive CAD (stenosis &lt;50%), and 1 patient (1.6%) had significant obstructive CAD (stenosis&gt;50%). This patient with obstructive CAD had a high grade lesion in the proximal left anterior descending artery that required intervention. 54/116 had non-zero CAC scores. Of these, 13 (24%) had obstructive CAD and 41 (76%) non-obstructive CAD. 42/116 (36%) patients had incidental findings on cardiac CT that are summarised in Abstract 111 table 1. These incidental findings resulted in further investigations, documented in Abstract 111 table 2. The mean radiation dose (± SEM) for CAC scoring was 0.61±0.03 mSv. The mean radiation dose (± SEM) for subsequent CTCA was 2.66 ± 0.32 mSv in high pitch “flash” mode (n=27), 5.86±0.50 mSv in prospective mode (n=64) and 17.15±1.68 mSv in the retrospective mode (n=25). <h3>Conclusions</h3> Despite 62 patients having a reassuring CAC score of zero, 8% of this group had evidence of non-calcified plaque, with one patient having obstructive CAD that required intervention. We conclude that if strong clinical suspicion remains in patients with a CAC score of zero further coronary investigation may be warranted. Incidental findings are common, and can result in multiple further investigations for patients. Further research is needed to evaluate the added cost, clinical benefits and radiation exposure created by investigation of such incidental findings in the context of cardiac CT.

Prevalence and Significance of Obstructive Coronary Artery Disease in Patients with Zero Coronary Artery Calcium Score

Abundant data have established coronary artery calcium score (CACS) in the algorithm of cardiovascular risk stratification, especially for those at intermediate risk of coronary artery disease (CAD). Absence of CACS is associated with a very low cardiac event rate in asymptomatic individuals and no further imaging is required. Cardiac event rates in symptomatic patients are comparatively higher but still relatively low and have to be interpreted in the context of the population included. Conflicting results from angiography literature with a reported presence of obstructive CAD in up to 39% of mostly symptomatic patients with zero CACS are explained by the higher-risk patients enrolled. CACS is an excellent test for asymptomatic patients in predicting cardiac events and absence of obstructive CAD but has a limited role in symptomatic and higher-risk patients encountered by a cardiovascular specialist, particularly those referred for CT angiography and invasive coronary angiography. This is especially true for relatively young patients (<45 years of age).

Computed Tomographic Coronary Artery Calcium Assessment for Evaluating Chest Pain in the Emergency Department: Long-term Outcome of a Prospective Blind Study

To determine the long-term outcome of computed tomographic (CT) quantification of coronary artery calcium (CAC) used as a triage tool for patients presenting with chest pain to an emergency department (ED). Patients (men aged 30-62 years and women aged 30-65 years) with chest pain and low-to-moderate probability of coronary artery disease underwent both conventional ED chest pain evaluation and CT CAC assessment prospectively. Patients' physicians were blinded to the CAC results. The results of the conventional evaluation were compared with CAC findings on CT, and the long-term outcome in patients undergoing CT CAC assessment was established. Primary end points (acute coronary syndrome, death, fatal or nonfatal non-ST-segment elevation myocardial infarction, fatal or nonfatal ST-segment elevation myocardial infarction) and secondary outcomes (coronary artery bypass grafting, percutaneous transluminal coronary angioplasty, coronary stenting, or a combination thereof) were obtained when the patient was dismissed from the ED or hospital and then at 30 days, 1 year, and 5 years. Of the 263 study patients, 133 (51%) had a CAC score of zero. This absence of CAC correlated strongly with the likelihood of noncardiac chest pain. Among 133 patients with a CAC score of zero, only 1 (<1%) had cardiac chest pain. Conversely, of the 31 patients shown to have cardiac chest pain, 30 (97%) had evidence of CAC on CT. When a CAC cutoff score of 36 was used, as suggested by receiver operating characteristic analysis, sensitivity was 90%; specificity, 85%; positive predictive value, 44%; and negative predictive value, 99%. During long-term follow-up, patients without CAC experienced no cardiac events at 30 days, 1 year, and 5 years. Findings suggest that CT CAC assessment is a powerful adjunct in chest pain evaluation for the population at low-to-intermediate risk. Absent or minimal CAC in this population makes cardiac chest pain extremely unlikely. The absence of CAC suggests an excellent long-term (5-year) prognosis, with no primary or secondary cardiac outcomes occurring in study patients at 5-year follow-up.

Diagnostik der koronaren Herzkrankheit – Teil 4: Computertomographie und Koronarangiographie

Invasive coronary angiography and computed tomography (CT) coronary angiography directly visualise coronary anatomy but do not provide information about the presence of inducible myocardial ischaemia. Due to its excellent negative predictive value CT coronary angiography is a suitable test to exclude significant coronary artery disease. However, given its high rate of false positive results particularly in the presence of significant coronary calcification CT coronary angiography only rarely is a real alternative to invasive coronary angiography in clinical practice. The coronary artery calcium score (CACS) is a surrogate for the extent of coronary atherosclerosis and a possible marker of biological age but does not provide any anatomical or pathophysiological information. In asymptomatic patients a CACS of zero is associated with a very low likelihood of a significant coronary stenosis and a good prognosis. However, this is not the case in symptomatic patients, and thus, CACS does not play a significant role in the diagnostic work-up in symptomatic patients in daily routine.

Carotid intima-media thickness and coronary artery calcium score as indications of subclinical atherosclerosis.

To determine the ability of carotid intima-media thickness (CIMT) and coronary artery calcium score (CACS) to detect subclinical atherosclerosis in a young to middle-aged, low-risk, primary-prevention population. Patients aged 36 to 59 years who underwent determination of CIMT and CACS at our institution between May 1, 2004, and April 1, 2008, were included in the study. Those with diabetes mellitus or a history of coronary, peripheral, or cerebral vascular disease were excluded. Other information, such as Framingham risk score (FRS), was obtained by a review of clinical and laboratory data. Of 118 patients, 89 (75%) had a CACS of zero and 94 (80%) were men; mean +/- SD age was 48.9+/-5.7 years. The mean FRS of this group was 4.0; 86 patients (97%) were considered at low risk (<1% annualized rate) of cardiovascular events. Evidence of carotid atherosclerosis was found in 42 (47%; 95% confidence interval, 37%-58%) of these 89 patients; carotid plaque was found in 30 (34%); and CIMT above the 75th percentile was found in 12 (13%) of age-, sex-, and race-matched control patients. Of the 40 patients with low-risk CIMT (below the 50th percentile), 4 (10%) had a CACS at or above the 50th percentile. Subclinical vascular disease can be detected by CIMT evaluation in young to middle-aged patients with a low FRS and a CACS of zero. These findings have important implications for vascular disease screening and the implementation of primary-prevention strategies.