Determinants of coronary artery calcification in maintenance hemodialysis patients

Predictive nomogram model for severe coronary artery calcification in end-stage kidney disease patients

INTRODUCTION

The Agatston coronary artery calcification score (CACS) is an assessment index for coronary artery calcification (CAC). This study aims to explore the characteristics of CAC in end-stage kidney disease (ESKD) patients and establish a predictive model to assess the risk of severe CAC in patients.

METHODS

CACS of ESKD patients was assessed using an electrocardiogram-gated coronary computed tomography (CT) scan with the Agatston scoring method. A predictive nomogram model was established based on stepwise regression. An independent validation cohort comprised of patients with ESKD from multicentres.

RESULTS

369 ESKD patients were enrolled in the training set, and 127 patients were included in the validation set. In the training set, the patients were divided into three subgroups: no calcification (CACS = 0, n = 98), mild calcification (0 < CACS ≤ 400, n = 141) and severe calcification (CACS > 400, n = 130). Among the four coronary branches, the left anterior descending branch (LAD) accounted for the highest proportion of calcification. Stepwise regression analysis showed that age, dialysis vintage, β-receptor blocker, calcium-phosphorus product (Ca × P), and alkaline phosphatase (ALP) level were independent risk factors for severe CAC. A nomogram that predicts the risk of severe CAC in ESKD patients has been internally and externally validated, demonstrating high sensitivity and specificity.

CONCLUSION

CAC is both prevalent and severe in ESKD patients. In the four branches of the coronary arteries, LAD calcification is the most common. Our validated nomogram model, based on clinical risk factors, can help predict the risk of severe coronary calcification in ESKD patients who cannot undergo coronary CT analysis.

Effects of overhydration, Kt/Vurea, β2-microglobulin on coronary artery calcification and mortality in haemodialysis patients

AIM

We studied the effects of overhydration (OH), Kt/Vurea and β2-microglobulin (β2-MG) on coronary artery calcification and mortality in patients undergoing haemodialysis (HD).

METHODS

The Agatston coronary artery calcium score (CACS), postdialysis body composition using bioimpedance analysis, single-pool Kt/Vurea and predialysis β2-MG at baseline were assessed and followed up for 3 years in patients undergoing HD. We performed logistic regression analyses for a CACS ≥400 and Cox proportional hazard analyses for all-cause and cardiovascular mortality.

RESULTS

The study involved 338 patients with a median age of 67 (56-74) years, dialysis duration of 70 (33-141) months and diabetes prevalence of 39.1% (132/338). Patients with a CACS ≥400 (n = 222) had significantly higher age, dialysis duration, male prevalence, diabetes prevalence, C-reactive protein, predialysis β2-MG, OH, extracellular water/total body water and overhydration/extracellular water (OH/ECW) but significantly lower Kt/Vurea than patients with a CACS <400 (n = 116) (p < .05). OH/ECW, Kt/Vurea and predialysis β2-MG were significant predictors of a CACS ≥400 (p < .05) after adjusting for age, dialysis duration, serum phosphate and magnesium. In all patients, cut-off values of OH/ECW, Kt/Vurea and predialysis β2-MG for a CACS ≥400 were 16%, 1.74 and 28 mg/L, respectively. After adjusting for dialysis duration, OH/ECW ≥16%, Kt/Vurea ≥1.74 and β2-MG ≥28 mg/L were significant predictors of 3-year all-cause mortality but not 3-year cardiovascular mortality.

CONCLUSION

Higher OH/ECW, higher predialysis β2-MG and lower Kt/Vurea values are significant risk factors for a CACS ≥400 and 3-year all-cause mortality in patients undergoing maintenance HD.

Do trace elements play a role in coronary artery calcification in hemodialysis patients?

PURPOSE

Abnormalities of trace elements have previously been linked to inflammatory processes in hemodialysis (HD) patients. We aimed to establish the trace element status of maintenance HD patients, to investigate the relationship between coronary artery calcification scores (CACs) and whole blood levels of trace elements.

METHODS

Patients undergoing HD in three times a week for > 6 months and age-and sex-matched controls were included from October 2015 to June 2016. Data were collected from patient files. All subjects' whole blood levels of trace elements were measured by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). CACs for patients were assessed by multi-detector computed tomography.

RESULTS

The 35 patients (male, 60%) with a mean age of 45.7 ± 10.4 years and 35 controls were included. HD patients showed significantly lower levels of selenium and uranium and higher cadmium (Cd), cobalt, lithium, manganese, nickel, lead, platinum, tin, strontium, and thallium levels compared to controls. Coronary artery calcification (CAC) was present in 21 patients (60%), and median CACs were 14.2 (IQR 0-149). Patients with CACs > median were significantly older, had a higher prevalence of hypertension and lower ALP levels than patients with CACs ≤ median. No significant differences in whole blood levels of trace elements were found between patients with CACs > median and patients with CACs ≤ median. A near significance was noted in median whole blood levels of Cd between these groups (P = 0.096). According to multivariate analysis, age was the only independent determinant for CAC development.

CONCLUSION

Age is independently associated with coronary vascular calcification. High Cd levels might play a role in CAC development in HD patients.

Gender-Related Differences in Chronic Kidney Disease-Associated Vascular Calcification Risk and Potential Risk Mediators: A Scoping Review

Vascular calcification (VC) involves the deposition of calcium apatite in vascular intima or media. Individuals of advanced age, having diabetes mellitus or chronic kidney disease (CKD) are particularly at risk. The pathogenesis of CKD-associated VC evolves considerably. The core driver is the phenotypic change involving vascular wall constituent cells toward manifestations similar to that undergone by osteoblasts. Gender-related differences are observed regarding the expressions of osteogenesis-regulating effectors, and presumably the prevalence/risk of CKD-associated VC exhibits gender-related differences as well. Despite the wealth of data focusing on gender-related differences in the risk of atherosclerosis, few report whether gender modifies the risk of VC, especially CKD-associated cases. We systematically identified studies of CKD-associated VC or its regulators/modifiers reporting data about gender distributions, and extracted results from 167 articles. A significantly higher risk of CKD-associated VC was observed in males among the majority of original investigations. However, substantial heterogeneity exists, since multiple large-scale studies yielded neutral findings. Differences in gender-related VC risk may result from variations in VC assessment methods, the anatomical segments of interest, study sample size, and even the ethnic origins of participants. From a biological perspective, plausible mediators of gender-related VC differences include body composition discrepancies, alterations involving lipid profiles, inflammatory severity, diversities in matrix Gla protein (MGP), soluble Klotho, vitamin D, sclerostin, parathyroid hormone (PTH), fibroblast growth factor-23 (FGF-23), and osteoprotegerin levels. Based on our findings, it may be inappropriate to monotonously assume that male patients with CKD are at risk of VC compared to females, and we should consider more background in context before result interpretation.

Coronary Computed Tomography Angiography in Diagnosing Obstructive Coronary Artery Disease in Patients with Advanced Chronic Kidney Disease: A Systematic Review and Meta-Analysis

INTRODUCTION

Coronary computed tomography angiography (CCTA) is emerging as an important noninvasive testing modality for coronary angiography. The performance characteristic of CCTA in patients with advanced kidney disease is unknown.

METHODS

We performed a systematic review and meta-analysis of studies specifically investigating the sensitivity and specificity of CCTA compared to coronary angiogram as a reference standard in patients with advanced kidney disease, defined as dialysis dependence or nearing kidney transplantation. Two independent investigators assessed studies for inclusion/exclusion, quality, and characteristics, while a third investigator adjudicated.

RESULTS

We identified 4 studies including a total of 217 patients, of whom 159 were dialysis dependent. Three of the 4 studies had a high risk of bias in patient selection and study flow, while 1 study rated low in all areas of bias. The studies were heterogeneous in their patient selection and CCTA protocol but consistent in their definition of obstructive coronary artery disease. The pooled sensitivity and specificity for CCTA were 0.96 (0.87-0.99) and 0.66 (0.57-0.74), respectively. When we restricted the analysis to dialysis-dependent patients, the pooled sensitivity and specificity for CCTA were 0.99 (0.74-1.00) and 0.67 (0.49-0.82), respectively.

CONCLUSIONS

Based on limited data, CCTA appears to have comparable sensitivity but lower specificity relative to the non-kidney disease population.

Prevalence of coronary artery calcification and its association with mortality, cardiovascular events in patients with chronic kidney disease: a systematic review and meta-analysis

PURPOSE

To date, the prevalence and prognostic role of coronary artery calcification (CAC) in patients with chronic kidney disease (CKD) have been investigated in several studies, but have yielded conflicting results. The aim of this meta-analysis is to derive a more precise estimation of CAC prevalence in CKD patients and its association with cardiovascular events and mortality.

METHODS

The relevant literature was identified and evaluated from inception until July 2018 through multiple search strategies on PubMed, Embase, and Web of Science. Cross-sectional or cohort (baseline data) studies reporting CAC prevalence were included. Data extracted from eligible studies were used to calculate effect estimates (ESs) and 95% confidence intervals (95%CI). We searched databases for observational studies that explored baseline CAC and subsequent cardiovascular or all-cause mortality risk in CKD patients.

RESULTS

The meta-analysis included 47 studies; 38 of these were included in the final analysis of CAC prevalence. The pooled prevalence of CAC in random effect model was 60% (95%CI 53-68%). CAC was positively associated with an increased risk of all-cause mortality (hazard ratio [HR] 3.44; 95%CI 2.40-4.94), cardiovascular mortality (HR 3.87; 95%CI 2.06-7.26), and cardiovascular events (HR 2.09; 95%CI 1.19-3.67), when comparing individuals in the top CAC score group to those in the bottom CAC score group.

CONCLUSIONS

The pooled prevalence of CAC is highly prevalent. CAC is independently associated with all-cause and cardiovascular mortality risk as well as cardiovascular events among CKD patients. In view of the high heterogeneity, larger clinical trials are still needed.

Association between vascular calcification assessed by simple radiography and non-fatal cardiovascular events in hemodialysis patients

BACKGROUND

Vascular calcification (VC) is one of the factors associated with cardiovascular mortality in hemodialysis (HD) patients. Recommendations concerning screening for VC differ. Possible ability to prevent and reversibility of VC are major subjects on debate whether screening for VC could improve outcomes of renal patients. The objective of the study was to evaluate the significance of simple vascular calcification score (SVCS) based on plane radiographic films and to test its association with non-fatal cardiovascular events in patients on chronic HD.

METHODS

A study population consisted of 95 prevalent HD patients in the HD unit of Hospital of Lithuanian University of Health sciences Kaunas Clinics. Clinical data and laboratory tests information were collected from medical records. SVCS was evaluated as it is described by Adragao et al. After measurement of VC, HD patients were observed for novel non-fatal cardiovascular events.

RESULTS

Patients were divided into two groups: SVCS≥3 (57 patients [60%]) and <3 (38 patients [40%]). The Kaplan-Meier survival curves show a significant difference in non-fatal cardiovascular events in the group with SVCS≥3 vs. <3 group (26.3% vs. 7.8%; log rank 5,49; P=0.018). Multivariate Cox regression analysis confirmed a negative impact of VC, hyperphosphatemia, and lower ejection fraction on cardiovascular events. No statistically significant differences were observed comparing parameters of Ca-P metabolism disorders between groups with different SVCS. On separate analysis, the presence of VC in hands was also associated with higher rate of novel cardiovascular events (score 0 goup-5 events [10.6%] vs. score≥1 group-13 events [27%], log rank P=0.035).

CONCLUSION

VC assessed by simple and inexpensive radiological method was an independent predictor of novel non-fatal cardiovascular events in HD patients.

Both pelvic radiography and lateral abdominal radiography correlate well with coronary artery calcification measured by computed tomography in hemodialysis patients: A cross-sectional study

Introduction Lateral abdominal radiograph is suggested as an alternative to coronary artery computed tomography (CT) in evaluating vascular calcification. Simple scoring systems including pelvic radiograph scoring and abdominal scoring system were utilized to study their correlation with coronary artery calcification. Methods In 106 MHD patients, coronary artery CT, lateral abdominal, and pelvic radiograph were taken. The Agatston scoring system was applied to evaluate the degree of coronary artery calcification which was categorized according to Agatston coronary artery calcification score (CACS) ≥ 30, ≥100, ≥400, and ≥1000. Abdominal aortic calcification was scored by 4-scored and 24-scored systems. Pelvic artery calcification was scored by a 4-scored system. Sensitivities and specificities of abdominal aortic calcification scores and pelvic artery calcification scores to predict different categories of coronary artery calcification were analyzed. We studied the diagnostic capability of abdominal aorta calcification and pelvic artery calcification to predict different CACS categories by calculating likelihood ratios. Receiver operator characteristic curves were used to determine the area under the curve for each of these testing procedures. Findings The prevalence was 48(45.3%), 15 (14.2%), 11 (10.4%), 11 (10.4%), and 11 (10.4%) for CACs > 0, ≥30, ≥100, ≥400, and ≥1000, respectively. The degree of CACs was positively correlated with patient age, prevalence of diabetes, abdominal aorta scores, and pelvic calcification scores. The areas under the curves for different CACS by all X-ray scoring systems were above 0.70 except pelvic 4-scored system for diagnosing CACS ≥30, without significant difference (P > 0.05). Discussion Both lateral abdominal and pelvic plain radiographs were demonstrated as acceptable alternatives to CT in evaluating vascular calcification.