Impact of coronary CT angiography in selection of treatment modalities and subsequent cardiovascular events in Thai patients with stable CAD.

BACKGROUND: Coronary computed tomography angiography (CCTA) enables improved diagnosis of subclinical, coronary artery disease (CAD). This retrospective cohort study investigated the association between different treatment modalities guided by CCTA and the prevention of major adverse cardiovascular events (MACEs) in patients with stable CAD. METHODS: From 2005 to 2013, a total of 9338 patients, including both asymptomatic individuals with risk factors and symptomatic patients with suspected CAD, who underwent CCTA were analyzed. The patients were categorized into one of three groups based on results of CCTA: obstructive CAD (≥ 50% stenosis in at least one vessel), non-obstructive CAD (1-49% stenosis in at least one vessel), and no observed CAD (0% stenosis). They were subsequently followed up to assess the treatment they received and the occurrence of MACEs (cardiovascular death, non-fatal myocardial infarction, non-fatal stroke, or late revascularization). RESULTS: During an average follow-up period of 9.9 ± 2.4 years, patients with obstructive CAD had the highest incidence of MACEs (19.8%), followed by those with non-obstructive CAD and no coronary artery stenosis (10.3 and 5.5%, respectively). After adjusting for confounding variables, it was found that patients treated with statins alone were the least likely to develop MACEs in all three groups, compared to those receiving no treatment, with hazard ratios (95% CI) of 0.43 (0.32, 0.58), 0.47 (0.34, 0.64), and 0.46 (0.31, 0.69), respectively. In patients with obstructive CAD, treatment with a combination of statin and aspirin, or early revascularization was associated with a lower likelihood of experiencing MACEs compared to no treatment with hazard ratios of 0.43 (0.33, 0.58) and 0.64 (0.43, 0.97), respectively. CONCLUSION: CCTA offers useful guidance for the treatment of patients with stable CAD and shows potential for prevention of CV events. However, the full validation of a given strategy utilizing CCTA will require a prospective longitudinal study, utilizing a randomized clinical trial design.

Utility of coronary artery calcium in refining 10-year ASCVD risk prediction using a Thai CV risk score.

Background: Coronary artery calcium (CAC) scanning is a valuable additional tool for calculating the risk of cardiovascular (CV) events. We aimed to determine if a CAC score could improve performance of a Thai CV risk score in prediction of 10-year atherosclerotic cardiovascular disease (ASCVD) risk for asymptomatic patients with CV risk factors. Methods: This was a retrospective cohort study that enrolled asymptomatic patients with CV risk factors who underwent CAC scans between 2005 and 2013. The patients were classified as low-, intermediate-, or high-risk (<10%, 10%-<20%, and ≥20%, respectively) of having ASCVD within 10-years based on a Thai CV risk score. In each patient, CAC score was considered as a categorical variable (0, 1-99, and ≥100) and natural-log variable to assess the risk of developing CV events (CV death, non-fatal MI, or non-fatal stroke). The C statistic and the net reclassification improvement (NRI) index were applied to assess whether CAC improved ASCVD risk prediction. Results: A total of 6,964 patients were analyzed (mean age: 59.0 ± 8.4 years; 63.3% women). The majority of patients were classified as low- or intermediate-risk (75.3% and 20.5%, respectively), whereas only 4.2% were classified as high-risk. Nearly half (49.7%) of patients had a CAC score of zero (no calcifications detected), while 32.0% had scores of 1-99, and 18.3% of ≥100. In the low- and intermediate-risk groups, patients with a CAC ≥100 experienced higher rates of CV events, with hazard ratios (95% CI) of 1.95 (1.35, 2.81) and 3.04 (2.26, 4.10), respectively. Incorporation of ln(CAC + 1) into their Thai CV risk scores improved the C statistic from 0.703 (0.68, 0.72) to 0.716 (0.69, 0.74), and resulted in an NRI index of 0.06 (0.02, 0.10). To enhance the performance of the Thai CV risk score, a revision of the CV risk model was performed, incorporating ln(CAC + 1), which further increased the C statistic to 0.771 (0.755, 0.788). Conclusion: The addition of CAC to traditional risk factors improved CV risk stratification and ASCVD prediction. Whether this adjustment leads to a reduction in CV events and is cost-effective will require further assessment.

Predictive values of coronary artery calcium and arterial stiffness for long-term cardiovascular events in patients with stable coronary artery disease.

BACKGROUND: Subclinical atherosclerosis detected by increased coronary artery calcium (CAC) or arterial stiffness as reflected by cardio-ankle vascular index (CAVI) has been associated with major adverse cardiovascular events (MACEs). However, comparative data from these two assessments in the same population are still limited. METHODS: From 2005 to 2013, patients with stable coronary artery disease (CAD), both asymptomatic and symptomatic who underwent both coronary computed tomography and CAVI were enrolled and followed for occurrence of MACEs (cardiovascular [CV] death, nonfatal myocardial infarction [MI], and nonfatal stroke) until December 2019. A cause-specific hazard model was applied to assess the associations of CAC score, and CAVI with long-term MACEs. RESULTS: A total of 8687 patients participated. Of them, CAC scores were 0, 1-99, 100-399, and ≥400 in 49.7%, 31.9%, 12.3%, and 6.1%, respectively. Arterial stiffness (CAVI ≥ 9.0) was associated with the magnitude of CAC in 23.8%, 36.3%, 44.5%, and 56.2%, respectively. During an average of 9.9 ± 2.4 years follow-up, MACEs occurred in 8.0% (95% CI: 7.4%, 8.6%) of subjects. After adjusting for covariables, CAC scores of 100-399 and ≥400, and CAVIs of ≥9.0 were found to independently predict the occurrence of MACEs with the hazard ratios (95% CI) of 1.70 (1.13, 1.98), 1.87 (1.33, 2.63), and 1.27 (1.06, 1.52), respectively. Other risk predictors were hypertension, diabetes mellitus (DM), chronic kidney disease (CKD), aspirin, and statin therapy. CONCLUSIONS: A CAC score ≥100 or a CAVI ≥ 9.0 predicts the long-term occurrence of MACEs in both asymptomatic and symptomatic patients with stable CAD. These two noninvasive tests can be used as screening tools to guide treatment for the prevention of future CV events.

Causal Relationship of Coronary Artery Calcium on Myocardial Infarction and Preventive Effect of Antiplatelet Therapy.

Background: The role of coronary artery calcium score (CACS) to guide antiplatelet therapy in order to prevent myocardial infarction (MI) is still uncertain. This study aimed to find the causal relationship of CACS on MI and preventive effect of antiplatelet therapy. Methods: From 2005 to 2013, all patients with cardiovascular risk factors or symptoms of suspected CAD underwent coronary computed tomography. CACSs were measured using Agatston method and stratified into 4 groups: 0, 1-99, 100-399, and ≥ 400. Antiplatelet therapy was prescribed following physician discretion. Outcomes of interest were MI and bleeding. A mediation analysis was applied to find association pathways. CACS was considered as an independent variable, whereas antiplatelet therapy was considered as a mediator and MI considered the outcome of interest. Results: A total of 7,849 subjects were enrolled. During an average of 9.9 ± 2.4 years follow-up, MI and bleeding events occurred in 2.24% (n = 176) and 2.82% (n = 221) of subjects, respectively. CACSs 100-399 and CAC ≥ 400 were significantly associated with the development of MI [OR 3.14 (1.72, 5.72), and OR 3.22 (1.66, 6.25), respectively, p < 0.001]. Antiplatelet therapy reduced the risk of MI of these corresponding CAC groups with ORs of 0.60 (0.41, 0.78) and 0.56 (0.34, 0.77), p < 0.001]. A risk of bleeding was associated with antiplatelet therapy (only aspirin), anticoagulant, hypertension, male gender and old age. Conclusion: CACS was associated with the development of future MI. The preventive effect of antiplatelet therapy was clearly demonstrated in subjects with CACSs equal to or above 100, but this benefit was partially offset by an increased risk of bleeding.

Dialysate Magnesium and Coronary Artery Calcification, Bone Mineral Density, and Cramping in Maintenance Hemodialysis: A Quasi-experimental Study.

RATIONALE & OBJECTIVE: Recent evidence suggests a role for magnesium as a calcification inhibitor. Increased magnesium abundance may attenuate vascular calcification and promote bone formation. STUDY DESIGN: Parallel-group, 1:1-allocation-ratio, quasi-experimental study. SETTING & PARTICIPANTS: The study was conducted at hemodialysis centers in Bangkok, Thailand. Patients receiving maintenance hemodialysis were screened for coronary artery calcification (CAC) and bone mineral density (BMD), and those with a CAC score of ≥300 were included and matched according to the initial CAC score. The intervention and control groups consisted of 20 patients in each arm. INTERVENTIONS: A high (1.75 mEq/L) or standard (0.7 mEq/L) dialysate magnesium concentration was delivered for 26 weeks. OUTCOMES: Changes in the CAC score and BMD and the progression of CAC. The safety outcomes included occurrence of cramps recorded as per usual care. RESULTS: The median CAC score of all patients was 1,792. Serum and ionized magnesium concentrations increased substantially in the high dialysate magnesium group. At the end of the study, the CAC score increased significantly in both the groups, with no significant difference between the groups. The number of participants with CAC progression was comparable between the 2 groups. In exploratory subgroup analyses stratified by the median CAC score, a significant decline in CAC and fewer participants with CAC progression were observed in the subgroup with lower CAC scores that received the high dialysis magnesium concentration. Bone mineral density was largely unchanged in both groups. The number of participants experiencing cramps and the number of episodes of muscle cramps were markedly lower among patients who received the high dialysis magnesium concentration. LIMITATIONS: The participants had severe vascular calcification at baseline; therefore, the findings might not apply to those with less-established calcification. Moreover, cramps were not systematically ascertained. CONCLUSIONS: The high dialysis magnesium concentration did not alleviate the progression of CAC or improve BMD in patients with severe calcification receiving hemodialysis; however, muscle cramps were less frequent among those treated with high dialysate magnesium. Further study is required to determine a possible favorable effect of high dialysis magnesium concentration in individuals with mild-to-moderate calcification.

Effect of Obesity on Left Ventricular Mass: Results from 320 Multi-Slices Computed Tomography.

Objective: To determine effects of obesity and gender on left ventricular mass in normotensive and hypertensive Thai patients using 320-slice cardiac computed tomography (CT). Material and Method: Left ventricular mass (LVM) obtained from 320-slice coronary CT angiogram was compared in 597 normotensive subjects (175 men [65 obese] and 422 women [133 obese], aged 55±7 years) and 483 hypertensive patients (180 men [104 obese] and 303 women [170 obese], aged 60±7 years). Obesity in Asian population was defined by body mass index (BMI) ≥ 25 kg/m2 in both genders. LV mass was normalized for body surface area (BSA)and height2.7. Results: The upper normal limit of LVM/ height2.7 developed from 244 (197 women, 47 men) low risk subjects (non-smoking normal-weight adults free from hypertension, diabetes, coronary artery disease & dyslipidemia) was lower than the established criteria for left ventricular hypertrophy (LVH) (31 versus 44 g/m2.7 in women; 36 versus 48 g/m2.7 in men). There is statistical difference between men and women in all groups of analysis. Among both hypertensive and normotensive subjects, the prevalence of LVH and LVM/height2.7 are higher in the obese group than normal-weight group in both genders (LVM/height2.7p<0.001; prevalence of LVH ­ obese versus normal-weight hypertension: 58% versus 34% in women, 43% versus 14% in men; obese versus normal-weight normotension: 35% versus 16% in women, 40% versus 15% in men). The same differences between obese and normal-weight groups were also present when normalizing LVM for height but not with LVM/BSA. Logistic regression analysis revealed that systolic blood pressure and BMI were the main predictors of LVH in the entire population (p<0.001 in both genders). Equations for predicting LVH in men and women were: Risk of LVH = 1/(l+e-w) where w is as follows: w (men) = 0.02* systolic pressure + 0.25*BMI ­ 9.86, w (women) = 0.03* systolic pressure + 0.17*BMI ­ 8.82. Conclusion: Obesity is an independent stimulus to increase LVM in normo-tensive subjects, and its effect is additive in hypertensive patients. Gender and obesity affect LVM and prevalence of LVH.

Low hip bone mineral density predicts mortality in maintenance hemodialysis patients: a five-year follow-up study.

BACKGROUND: Bone loss is common among hemodialysis patients and contributes to mortality. The association between bone loss and vascular calcification may explain the increased mortality risk. Studies on the association between decreased bone mass and mortality in maintenance hemodialysis patients are limited. METHODS: Eighty-three hemodialysis patients underwent bone mineral density (BMD) and coronary artery calcification (CAC) measurements. The relationship between BMD and mortality was analyzed after a 5-year follow-up period. RESULTS: Eighty percent of the patients had reduced hip BMD. In univariate Cox regression analyses, age, cardiovascular disease, dyslipidemia, increased CAC score, increased comorbidity score and decreased hip BMD were associated with mortality. Low hip BMD remained independently associated with mortality after adjustments for cardiovascular risk factors, comorbidity score and CAC score. Patients with BMD in the lowest tertile had the worst survival. CONCLUSION: Low hip BMD predicted mortality in maintenance hemodialysis patients independent of CAC.

Arterial stiffness contributes to coronary artery disease risk prediction beyond the traditional risk score (RAMA-EGAT score).

OBJECTIVES: The traditional risk score (RAMA-EGAT) has been shown to be an accurate scoring system for predicting coronary artery disease (CAD). Arterial stiffness measured by the cardio-ankle vascular index (CAVI) is known to be a marker of atherosclerotic burden. A study was undertaken to determine whether CAVI improves the prediction of CAD beyond the RAMA-EGAT score. DESIGN: Cross-sectional study. PATIENTS: Patients with a moderate to high risk for CAD by the RAMA-EGAT score were enrolled between November 2005 and March 2006. 64-slice multidetector CT coronary angiography was used to evaluate the coronary artery calcium score and coronary stenosis. Arterial stiffness was assessed by CAVI. RESULTS: 1391 patients of median age 59 years (range 31-88) were enrolled in the study, 635 (45.7%) men and 756 (54.3%) women. Of the 1391 patients, 346 (24.87%) had coronary stenosis. There was a correlation between CAVI and the prevalence of coronary stenosis after adjusting for traditional CAD risk factors (OR 3.29). In addition, adding CAVI into the RAMA-EGAT score (modified RAMA-EGAT score) improved the prediction of CAD incidence, increasing C-statistics from 0.72 to 0.85 and resulting in a net reclassification improvement of 27.7% (p<0.0001). CONCLUSION: CAVI is an independent risk predictor for CAD. The addition of CAVI to the RAMA-EGAT score significantly improves the diagnostic yield of CAD.

Normal data of left ventricular parameters in non-hypertensive patients using 320-slice cardiac CT: a study on intra- and interobserver variability.

OBJECTIVE: Delineate normal data in a Thai population for global left ventricular function, left ventricular mass (LVM), and LV mass index (LVMI) by gated volumetric CT angiography (CTA). MATERIAL AND METHOD: Two hundred twenty seven patients with intermediate risk factors for CAD were referred for CT coronary angiography. The non-hypertensive and non-diabetic asymptomatic group was selected with negative coronary CTA. Pre-condition of mild stenosis or less than 50% area stenosis was consistently met for inclusion in the present study. One hundred fifteen patients were included (31 males, 84 females, age range 38-76 years, mean 54.6 +/- 7.2 for males and 54.0 +/- 6.8 for females respectively). RESULTS: Mean EDV, ESV, SV, CO, and EF in male and females were EDV 122.6 +/- 17.3 vs. 94.9 +/- 16.6ml, ESV 48.2 +/- 9.9 vs. 34.1 +/- 9.1 ml, SV 74.5 +/- 14.2 vs. 60.8 +/- 10.6 ml, CO 4.2 +/- 0.8vs. 3.6 +/- 0.7 Land EF 60.6 +/- 6.6 vs. 64.3 +/- 5.6% respectively The mean LVM and LVMI were higher in males than females (LVM 134.6 +/- 21.4 vs. 96 9 +/- 20.3 g, and LVMI 76.8 +/- 12.4 vs. 61.1 +/- 11.56 g/m2). Altman and Bland plot for each of them showed that the mean and standard deviation of the differences was constant throughout the range of measurements. Each histogram of differences showed that these differences correspond to approximately normal distribution, indicating that the required assumptions held for the use of 95% limits of agreement are valid. CONCLUSION: Data from this group represents healthy volunteers and this may serve as an important source of information representing normal reference values to be used for Thai patients.

International reproducibility of single breathhold T2* MR for cardiac and liver iron assessment among five thalassemia centers.

PURPOSE: To examine the reproducibility of the single breathhold T2* technique from different scanners, after installation of standard methodology in five international centers. MATERIALS AND METHODS: Up to 10 patients from each center were scanned twice locally for local interstudy reproducibility of heart and liver T2*, and then flown to a central MR facility to be rescanned on a reference scanner for intercenter reproducibility. Interobserver reproducibility for all scans was also assessed. RESULTS: Of the 49 patients scanned, the intercenter reproducibility for T2* was 5.9% for the heart and 5.8% for the liver. Local interstudy reproducibility for T2* was 7.4% for the heart and 4.6% for the liver. Interobserver reproducibility for T2* was 5.4% for the heart and 4.4% for the liver. CONCLUSION: These data indicate that T2* MR may be developed into a widespread test for tissue siderosis providing that well-defined and approved imaging and analysis techniques are used.

Visceral fat and insulin resistance as predictors of non-alcoholic steatohepatitis.

AIM: To examine whether visceral fat is associated with non-alcoholic steatohepatitis (NASH), to assess for parameters associated with visceral adiposity and to investigate for factors associated with fibrotic severity in NASH. METHODS: Thirty NASH and 30 control subjects underwent biochemical tests, anthropometric assessment, bioelectrical impedance, dual energy X-ray absorptiometry and abdominal fat study by CT scan. Liver biopsies were graded according to the Brunt criteria. RESULTS: NASH subjects had elevated blood pressure, body mass index, waist circumference and waist-to-hip ratio. A greater number of diabetes mellitus, impaired glucose tolerance test and HOMA-IR > 3.5 were found in NASH patients. HOMA-IR > 2.8 (OR 20.98, 95% CI 3.22-136.62; P < 0.001) and visceral fat area > 158 cm(2) (OR 18.55, 95% CI 1.60-214.67; P = 0.019) were independent predictors for NASH. Advanced stage of NASH was found in 15 (50%) patients. HOMA-IR > 3.5 (OR 23.12, 95% CI 2.00-266.23; P = 0.012) and grading of portal inflammation (OR 7.15, 95% CI 1.63-31.20; P = 0.009) were determined as independent risk factors for advanced stage of NASH. CONCLUSION: Obesity (especially central obesity) and metabolic syndrome are common in Thai NASH. Insulin resistance and elevated visceral fat are risk factors for the presence of NASH. The advanced stage of the disease is related to insulin resistance.

Cardiovascular examination with 3.0 Tesla magnetic resonance imaging: first 100 cases at Ramathibodi Hospital.

BACKGROUND: Cardiovascular magnetic resonance imaging (CMR) has been utilized for diagnosis in various cardiovascular diseases and most of those were performed on a 1.5 Tesla CMR system. Recently, a 3.0 Tesla magnetic resonance imaging system has been introduced into clinical practice, however the clinical experience on cardiovascular examination using this system is limited. Therefore, the authors' institution has integrated a team for developing a CMR program on this 3.0 Tesla system. OBJECTIVE: To describe the authors' experience on the 3.0 Tesla CMR system. MATERIAL AND METHOD: The data on patients referred to the authors' CMR unit between August 2004 and October 2005 were reviewed. RESULTS: One hundred patients were referred for CMR examination. The mean age was 56 years (2 month - 85 years) and 65 patients were male. The most common indication was to assess coronary artery disease (64 patients). The performed examination was divided into cardiac structure and function assessment (39%), stress testing (23%), coronary magnetic resonance angiography (13%), myocardial viability assessment (12%), magnetic resonance angiography (9%), and flow assessment (4%). CONCLUSION: The present study highlights that comprehensive assessment of various cardiovascular diseases can be performed on the 3.0 Tesla CMR system.

Accuracy of sixteen-slice CT scanners in detected coronary artery disease.

BACKGROUND: The coronary artery disease, now, the incidence is increasing in both developed and developing countries. The investigation is evoluted and non-invasive multislice CT scanners have been used more frequently, although the gold standard is still the coronary angiography. OBJECTIVE: To investigate the accuracy in detected coronary artery disease by using 16-slice CT scanners compared to the conventional coronary angiography. MATERIAL AND METHOD: Fifty-five patients were 43 males, 12 females, median aged 62 years (43-82 years), and average heart rates 67 beats/minute (46-147 beats/minute) had the ECG-gated CT angiography followed by coronary angiography in 3 months. The ECG-gated CT angiography was performed by using 16-slice MSCT detector (0.42-s rotation time, 16 x 0. 75-mm detector collimation). RESULTS: All patients were classified into two major groups; one was significant coronary artery stenosis which was designed by stenosis at least 50% and the other was non-significant stenosis which was designed by normal or stenosis less than 50%. The site having blooming artifact due to calcification that causes complete obliteration of the lumen or having significant motional artifacts was ruled out. There were 285 evaluable sites in 19 patients with high heart rates, more than 70 beats/minute. The sensitivity, specificity, and accuracy in significant stenosis were 72.9%, 99.6%, and 94.0% respectively. In 36 patients with a lower heart rate, there were 563 evaluable sites, the sensitivity was 86.5%, specificity was 98.5%, and accuracy was 96.6%. The overall showed 81.1% of sensitivity, 98.9% of specificity, and 95.8% of accuracy. CONCLUSION: The accuracy of the 16-slice CT angiography for patients suspected of having coronary artery disease was high. However, blooming artifacts from the calcium, respiratory artifacts, and small size of the distal and branching artery still caused limited luminal assessment. These problems have challenged the new coming generation of MDCT.

Cardiac CT angiography: comprehensive assessment of patient suspected coronary artery disease.

Coronary artery disease is the leading cause of mortality and morbidity worldwide. Although coronary angiography is currently a gold standard for diagnosis of coronary artery disease, some patients are of concern regarding small but not negligible risk of complications and discomfort of the procedure. In recent years, cardiac computerized tomographic angiography (CTA) is an attractive non-invasive modality for evaluation of chest pain in patients suspected to have coronary artery disease. The authors report a 61 year-old-man with a history of hypertension and hypercholesterolemia who presented with exertional angina pectoris for 3 weeks. Cardiac CTA was performed and revealed a severely stenotic lesion at the proximal left anterior descending coronary artery (LAD) with left ventricular ejection fraction of 53% and hypokinesia of anteroseptal and apical wall. The patient then was planned and underwent percutaneous coronary interventional procedure. This case highlights the utility of comprehensive information from cardiac CTA as a modality for coronary interventional procedure planning.