Serum uric acid: a forgotten prognostic marker in acute coronary syndromes?

The impact of uric acid on acute coronary syndrome prognosis in elderly patients

BACKGROUND

Uric acid (UA) plays an important role in cardiovascular diseases, yet its implications in elderly patients remains incompletely understood. This study aimed to explore the impact of UA on the prognosis in advanced-age patients with acute coronary syndrome (ACS).

METHODS

We included 526 patients aged 80 and older who were diagnosed with ACS. The UA levels were measured at admission, and patients were divided into four groups based on quartiles of UA levels. Major adverse cardiovascular events (MACE) during follow-up were recorded.

RESULTS

The median UA level was 344.09 μmol/L, while the median follow-up duration was 64 months. Kaplan-Meier curves demonstrated a higher cumulative incidence of MACE during long-term follow-up in the Q4 group (Log-rank p < 0.05). Cox regression analysis revealed an independent correlation between UA levels and an increased risk of MACE (HR 1.002, 95%CI 1.000-1.003, p = 0.021). The ROC curve indicated that the optimal UA value for predicting MACE was 324.25 μmol/L. After matching through PSM, the MACE-free survival rate was lower in both hyperuricemia group (UA> 420.00 μmol/L) and high UA group (324.25 μmol/L < UA≤ 420.00 μmol/L) compared to the control group. Both hyperuricemia and high UA levels were independent risk factors for long-term MACE in advanced-age ACS patients, with HR values of 1.546 (1.049-2.280, p = 0.028) and 1.491 (1.011-2.198, p = 0.044), respectively.

CONCLUSION

Elevated UA levels were identified as independent risk factors for MACE in elderly patients with ACS. The optimal predictive value of UA for poor cardiovascular prognosis was significantly lower than the traditional definition of hyperuricemia.

Asymptomatic hyperuricemia: to treat or not a threat? A clinical and evidence-based approach to the management of hyperuricemia in the context of cardiovascular diseases

Asymptomatic hyperuricemia is defined by serum uric acid levels above 6.2 mg/dl in women and 7 mg/dl in men. In the presence of monosodium urate crystal formation and articular inflammation, hyperuricemia may become symptomatic (namely nephrolithiasis and gout). Uric acid results from purine catabolism and is at the centre of a complex metabolic interplay that involves oxidative stress, inflammation, renin-angiotensin-aldosterone system (RAAS) activation and insulin resistance. Uric acid levels present a continuous relation with conditions like hypertension and chronic kidney disease (CKD) and are reported to have an impact on risk of cardiovascular events. However, whether elevated uric acid is a causal agent and thus a possible therapeutic target is still uncertain and matter of further investigation. Treating symptomatic hyperuricemia involves lowering uric acid drugs and controlling inflammation. Urate-lowering agents are well tolerated but show minimal impact on cardiovascular events in patients with gout. Use of direct-acting urate-lowering agents in asymptomatic hyperuricemia associated with cardiovascular diseases does not warrant a clear benefit, whereas addressing cardiovascular issues with guideline-recommended therapies lowers uric acid and reduces the occurrence of cardiovascular events. Regular assessment of uric acid and clinical symptoms is advised before starting and renewing a urate-lowering treatment.

A Ten-Year Follow-Up Study of the Association Between Uric Acid and Adverse Cardiovascular Events in Patients With Coronary Artery Disease

The association between uric acid (UA) and long-term mortality in patients with coronary artery disease is poorly investigated. We assessed the association between UA and 10-year mortality after percutaneous coronary intervention (PCI) in 3,998 patients who underwent PCI. Patients were categorized in groups according to UA tertiles: tertile 1 (UA <5.80 mg/100 ml, n = 1,347), tertile 2 (UA 5.80 to 7.04 mg/100 ml, n = 1,340), and tertile 3 (UA >7.94 mg/100 ml, n = 1,311). The primary outcome was 10-year all-cause mortality. All-cause deaths occurred in 1,200 patients: 320 deaths (26.5%) in patients with UA in the first tertile, 325 deaths (26.9%) in patients with UA in the second tertile, and 555 deaths (46.0%) in patients with UA in the third tertile (adjusted hazard ratio 1.22, 95% confidence interval 1.17 to 1.27, p <0.001) for 1 mg/100 ml increment in UA level. Cardiac deaths occurred in 748 patients: 194 deaths (16.5%) in patients with UA in the first tertile, 202 deaths (17.0%) in patients with UA in the second tertile, and 352 deaths (29.7%) in patients with UA in the third tertile (adjusted hazard ratio 1.24 [1.17 to 1.32], p <0.001) for 1 mg/100 ml increment in the UA level. The 10-year rates of target lesion revascularization, target vessel revascularization, or nontarget vessel revascularization did not differ significantly according to the UA level. In conclusion, in patients with coronary artery disease treated with PCI, increased UA level was associated with higher 10-year mortality. Increased UA level was not associated with the progression of atherosclerosis in nontreated coronary vessels or progression of intimal hyperplasia in stented lesions requiring intervention.

Investigation of the association between serum uric acid levels and HEART risk score in patients with acute coronary syndrome

The association between uric acid (UA) and cardio-metabolic conditions has been recognized for a long time. However, recently, a body of evidence has highlighted the independent role of UA in a series of conditions, including renal and cardiovascular diseases. In this light, data regarding the prognostic role of UA in acute coronary syndrome (ACS) is scarce. A total number of 100 patients, 59 males and 41 females, diagnosed with ACS were recruited in this study. At the time of admission to the hospital, the serum level of UA was measured. In addition, the HEART score was calculated based on each patients' profile. Participants were on average 61.37 ± 12.08 years old. The most prevalent risk factors were hypertension (48%), a history of coronary artery disease (40%), and diabetes mellitus (33%). The average serum level of UA was 5.81 ± 1.81 mg/dl, and the calculated HEART score had a median of six (minimum of two and maximum of ten). A positive yet statistically insignificant correlation was found between the measured UA level and the calculated HEART score (R = 0.375, p = 0.090). However, further studies with larger sample size are required to assess the direct association of UA level with major adverse cardiac events in patients with cardiovascular disease.

High Uric Acid Levels in Acute Myocardial Infarction Provide Better Long-Term Prognosis Predictive Power When Combined with Traditional Risk Factors

The current study aimed to investigate the association between serum UA levels and the mortality rate of AMI patients. We analyzed 5888 patients with successfully revascularized AMI (mean age: 64.0 ± 12.7 years). The subjects were divided into the high UA group (uric acid >6.5 mg/dL for males, >5.8 mg/dL for females) or the normal UA group based on initial serum UA level measured at admission. The primary outcome was all-cause mortality. A total of 4141 (70.3%) and 1747 (29.7%) patients were classified into the normal UA group and high UA groups, respectively. Over a median follow-up of 5.02 (3.07, 7.55) years, 929 (21.5%) and 532 (34.1%) patients died in each group. Cox regression analysis identified high UA levels as an independent predictor of all-cause mortality (unadjusted hazard ratio (HR) 1.69 [95% CI 1.52−1.88]; p < 0.001, adjusted HR 1.18 [95% CI: 1.05−1.32]; p = 0.005). The results were consistent after propensity-score matching and inverse probability weighting to adjust for baseline differences. The predictive accuracies of conventional clinical factor discrimination and reclassification were significantly improved upon the addition of hyperuricemia (C-index 0.788 [95% CI 0.775−0.801]; p = 0.005, IDI 0.004 [95% CI 0.002−0.006]; p < 0.001, NRI 0.263 [95% CI 0.208−0.318]; p < 0.001).

From Classic to Modern Prognostic Biomarkers in Patients with Acute Myocardial Infarction

Despite all the important advances in its diagnosis and treatment, acute myocardial infarction (AMI) is still one of the most prominent causes of morbidity and mortality worldwide. Early identification of patients at high risk of poor outcomes through the measurement of various biomarker concentrations might contribute to more accurate risk stratification and help to guide more individualized therapeutic strategies, thus improving prognoses. The aim of this article is to provide an overview of the role and applications of cardiac biomarkers in risk stratification and prognostic assessment for patients with myocardial infarction. Although there is no ideal biomarker that can provide prognostic information for risk assessment in patients with AMI, the results obtained in recent years are promising. Several novel biomarkers related to the pathophysiological processes found in patients with myocardial infarction, such as inflammation, neurohormonal activation, myocardial stress, myocardial necrosis, cardiac remodeling and vasoactive processes, have been identified; they may bring additional value for AMI prognosis when included in multi-biomarker strategies. Furthermore, the use of artificial intelligence algorithms for risk stratification and prognostic assessment in these patients may have an extremely important role in improving outcomes.

Evaluation of the prognostic ability of serum uric acid for elderly acute coronary syndrome patients with diabetes mellitus: a prospective cohort study

OBJECTIVES

This study evaluated the prognostic power of serum uric acid (UA) in predicting adverse events in elderly acute coronary syndrome (ACS) patients with diabetes mellitus (DM).

METHODS

The analysis involved 718 ACS patients ‍>80 years old whose general clinical data and baseline blood biochemical indicators were collected prospectively from January 2006 to December 2012. These patients were classified into two groups based on DM status, and then followed up after discharge. The Kaplan-Meier method was used for major adverse cardiac event (MACE) rates and all-cause mortality. Multivariate Cox regression was performed to analyze the relationship between UA level and long-term clinical prognosis. Receiver operating characteristic (ROC) curves were analyzed to predict the cutoff value of UA in elderly ACS patients with DM. There were 242 and 476 patients in the DM and non-DM (NDM) groups, respectively, and the follow-up time after discharge was 40‒120 months (median, 63 months; interquartile range, 51‒74 months).

RESULTS

The all-cause mortality, cardiac mortality, and MACE rates in both DM and NDM patients were higher than those in the control group (P=0.001). All-cause mortalities, cardiac mortalities, and MACE rates in DM patients with moderate and high UA levels were significantly higher than those in the NDM group (P=0.001). Long-term survival rates decreased significantly with increased UA levels in the ACS groups (P=0.001). UA (odds ratio (OR)=2.106, 95% confidence interval (CI)=1.244‒3.568, P=0.006) was found to be an independent risk factor for all-cause mortality and MACE in elderly ACS patients with DM. The cutoff value of UA was 353.6 μmol/L (sensitivity, 67.4%; specificity, 65.7%).

CONCLUSIONS

Serum UA level is a strong independent predictor of long-term all-cause death and MACE in elderly ACS patients with DM.

Impact of admission serum acid uric levels on in-hospital outcomes in patients with acute coronary syndrome

BACKGROUND

To assess the association between admission serum uric acid (SUA) levels and in-hospital outcomes in a real-world patients population with acute coronary syndrome (ACS) and to investigate the potential incremental prognostic value of SUA added to GRACE score (GRACE-SUA score).

METHODS

The data of consecutive ACS patients admitted to Coronary Care Unit of San Paolo and Niguarda hospitals in Milan (Italy) were retrospectively analyzed.

RESULTS

1088 patients (24% female) were enrolled. Mean age was 68 years (IQR 60-78). STEMI and NSTE-ACS patients were 504 (46%) and 584 (54%) respectively. SUA (OR 1.72 95%CI 1.33-2.22, p < 0.0001) and GRACE score (OR 1.04 95%CI 1.02-1.06, p < 0.0001) were significantly associated with an increased risk of in-hospital death at the multivariate analysis. Admission values of SUA were stratified in four quartiles. Rates of acute kidney injury, implantation of intra-aortic balloon pump and non-invasive ventilation use were significantly higher in the last quartile compared to Q1, Q2 and Q3 (p < 0.01). The areas under the ROC curve (AUC) for GRACE score and for SUA were 0.91 (95% CI 0.89-0.93, p < 0.0001) and 0.79 (95% CI 0.76-0.81, p < 0.0001) respectively. The AUC was larger for predicting in-hospital mortality with the GRACE-SUA score (0.94; 95% CI 0.93-0.95).

CONCLUSIONS

High admission levels of SUA are independently associated with in-hospital adverse outcomes and mortality in a contemporary population of ACS patients. The inclusion of SUA to GRACE risk score seems to lead to a more accurate prediction of in-hospital mortality in this study population.

Uric Acid Level is Positively Associated With NT-proBNP Concentration in Slovak Heart Failure Patients

Increased concentration of uric acid (UA) is positively associated with the clinical severity but negatively associated with the prognosis of heart failure (HF). However, data related to the association between UA concentration and N-terminal pro brain natriuretic peptide (NT-proBNP) are still lacking. The aim of the study was to analyze the relationships between UA, NT-proBNP, clearance of creatinine and NYHA function class and echocardiographic variables in the Slovak population of primary care patients diagnosed with HF. The association between UA and NT-proBNP was assessed by multivariate analysis. 848 patients (402 men, 446 women) with HF were included in the study. NT-proBNP correlated with UA in both men and women after adjustment based on age, BMI and glomerular filtration rate (r=0.263, p<0.0001; r=0.293, p<0.0001). UA concentration rose with the severity of the NYHA class and was significantly higher in patients with moderate and severe systolic dysfunctions as well as with diastolic dysfunction in the multivariate analysis. In conclusion, our study in Slovak population with HF has revealed a positive correlation between the concentration of UA and NT-proBNP, and the independency of this association on confounding factors. The results support the role of UA as a biochemical marker of HF severity and prognosis.

Prognostic value of serum uric acid levels in patients with non-STEMI undergoing percutaneous coronary intervention

BACKGROUND

Because myocardial infarction in young adults is rare, there has been limited research on the condition in this patient group. Very few data are available regarding the long-term outcomes of patients under 40 years of age with non-ST-segment elevation myocardial infarction (NSTEMI) undergoing invasive treatments. The prognostic value of uric acid (UA) in young patients with NSTEMI who undergo percutaneous coronary intervention (PCI) has also not been studied. The purpose of this study was to evaluate the long-term clinical outcomes of this specific subset of young patients. In addition, we aimed to identify the role of serum UA in predicting the long-term prognosis of young patients with NSTEMI who have undergone PCI.

METHODS

We performed a retrospective analysis of 213 young adult patients (≤40 years old) with NSTEMI who underwent PCI during their hospitalization at our tertiary referral center.

RESULTS

The mean age of the 213 patients was 36.8 ± 3.3 years (range, 21-40 years). The median follow-up was 930 days. Our patients were predominantly male (88.3%) and the most frequent traditional cardiovascular risk factors were smoking and dyslipidemia. Baseline TIMI flow 0-1, estimated glomerular filtration rate (eGFR), and UA were found to be independently correlated with long-term major adverse cardiovascular events (MACEs) in multivariate Cox regression analysis.

CONCLUSION

In the present study, baseline TIMI flow 0-1, admission eGFR, and UA levels were correlated with MACEs during long-term follow-up in young patients with NSTEMI.

Prognostic value of hyperuricemia in patients with acute coronary syndrome: A meta-analysis

BACKGROUND

The prognostic significance of elevated circulating uric acid level in patients with acute coronary syndrome (ACS) is conflicting. This meta-analysis aimed to assess the prognostic value of hyperuricemia in patients with ACS.

METHODS

A comprehensive literature search was performed in Pubmed, Embase, VIP, CNKI and WanFang databases up to 16 June 2018. All observational studies that investigated the prognostic value of hyperuricemia in ACS patients were selected. Outcome of interests was major adverse cardiovascular events (MACEs), all-cause mortality or cardiovascular mortality.

RESULTS

A total of nine studies enrolling 8776 ACS patients were included and analysed. ACS patients with hyperuricemia had an increased risk of MACEs (risk ratio [RR]: 1.86; 95% confidence intervals [CI]: 1.47-2.35), all-cause mortality (RR 1.86; 95% CI: 1.49-2.32) and cardiovascular mortality (RR: 1.74; 95% CI: 1.36-2.22) after adjustment for the conventional risk factors. Stratified analysis showed that the prognostic significance of hyperuricemia was consistently observed in each subgroups.

CONCLUSIONS

This meta-analysis suggests that hyperuricemia independently predicts MACEs and death in ACS patients. Determination of uric acid level has potential to improve risk stratification of adverse outcomes in ACS patients.

Serum Uric Acid Could Differentiate Acute Myocardial Infarction and Unstable Angina Pectoris in Hyperuricemic Acute Coronary Syndrome Patients

Introduction:

Serum uric acid (SUA) is the final product of purine metabolism in humans.

Aim:

The present study aimed to identify a potential association between serum UA and cardiac troponin I (cTnI) levels and to find out whether uric acid could differentiate patients presenting with the acute myocardial infarction (AMI) and unstable angina pectoris (UAP) in hyperuricemic and normouricemic acute coronary syndrome (ACS) patients.

Methods:

Eighty ACS patients, aged 50-83 years, were enrolled in the study, 40 of them presenting with AMI and 40 with UAP. Frequency of patients with serum uric level over threshold for hyperuricemia was investigated and two groups of patients were formed such as hyperuricemic and normouricemic groups (A and B groups, respectively) independently of type of ACS. Those groups of patients were also subjected to cTnI measurement.

Results:

Levels of SUA are associated with the type of ACS in the hyperuricemic ACS patients (AMI versus UAP, 499(458-590), 425(400-447) mmol/L, p=0.007, respectively). Uric acid correlated significantly with cTnI, moderate positively in the group A (rho=0.358, p=0.038) and moderate negatively in the group B (r=-0.309, p=0.037) of ACS patients. Multiple logistic regression analysis revealed that cTnI and age were independently associated with the SUA levels in the group A of ACS patients.

Conclusions:

Serum uric acid differentiates AIM and UAP patients in hyperuricemic group of acute coronary syndrome. Therefore it can be used as nonspecific parameter for evaluation of the myocardial lesion extent only in hyperuricemic ACS patients. This is supported by finding that cTnI along with age predicts SUA level in hyperuricemic ACS patients.

Uric acid is associated with long-term adverse cardiovascular outcomes in patients with acute coronary syndrome undergoing percutaneous coronary intervention

BACKGROUND AND AIMS

Evidence links uric acid (UA) with the promotion of cardiovascular disease. We assessed the prognostic value of UA on long-term major adverse outcomes (MACE) in patients with acute coronary syndrome (ACS), undergoing percutaneous coronary intervention (PCI).

METHODS

As primary endpoint, we assessed the association of UA (continuous and dichotomized) with MACE, including cardiovascular death, myocardial infarction (MI) and stroke, using Cox regression and propensity matching. As secondary endpoints, the influence of hyperuricemia (defined as UA levels > 6.0 mg/dl in women, and >7.0 mg/dl in men) was analysed separately for cardiovascular death, MI, and stroke. The incremental prognostic value of UA was tested using the net reclassification improvement (NRI), and the integrated discrimination improvement (IDI).

RESULTS

We included 1215 patients. Hyperuricemia was present in 356 (29.3%) patients. Mean follow-up was 5.5 years. UA (HR 1.091 [1.035-1.150]; p = 0.001) and hyperuricemia (HR 1.750 [1.388-2.207]; p < 0.001) were significantly associated with MACE. Results were consistent between Cox regression and propensity matched analysis. Patients with hyperuricemia had a 1.6-fold increased relative risk for cardiovascular death (p = 0.005) and a 1.5-fold increased risk for MI (p = 0.032). For stroke, hyperuricemia only constituted a confounder (HR 1.104; p = 0.970). The prognostic accuracy of an established risk prediction model was significantly increased by adding UA (continuous NRI p = 0.004; categorical NRI p = 0.029; IDI p = 0.002).

CONCLUSIONS

Our data suggest an independent association of elevated UA with long-term MACE in ACS patients undergoing PCI. Whether lowering UA might be beneficial remains to be elucidated in large clinical trials.

Gouty arthritis: decision-making following dual-energy CT scan in clinical practice, a retrospective analysis

To establish whether dual-energy CT (DECT) is a diagnostic tool, i.e., associated with initiation or discontinuation of a urate lowering drug (ULD). Secondly, to determine whether DECT results (gout deposition y/n) can be predicted by clinical and laboratory variables. Digital medical records of 147 consecutive patients with clinical suspicion of gout were analyzed retrospectively. Clinical data including medication before and after DECT, lab results, and results from diagnostic joint aspiration and DECT were collected. The relationship between DECT results and clinical and laboratory results was evaluated by univariate regression analyses; predictors showing a p < 0.10 were entered in a multivariate logistic regression model with the DECT result as outcome variable. A backward stepwise technique was applied. After the DECT, 104 of these patients had a clinical diagnosis of gout based on the clinical judgment of the rheumatologist, and in 84 of these patients, the diagnosis was confirmed by demonstration of monosodium urate (MSU) crystals in synovial fluid (SF) or by positive DECT. After DECT, the current ULD was modified in 33 (22.4%) of patients; in 29 of them, ULD was started and in 1 it was intensified. Following DECT, the current ULD was stopped in three patients. In the multivariable regression model, cardiovascular disease (OR 3.07, 95% CI 1.26-7.47), disease duration (OR 1.008, 95% CI 1.001-1.016), frequency of attack (OR 1.23, 95% CI 1.07-1.42), and creatinine clearance (OR 2.03, 95% CI 0.91-1.00) were independently associated with positive DECT results. We found that the DECT result increases the confidence of the prescribers in their decision to initiation or discontinuation of urate lowering therapy regimen in of mono- or oligoarthritis. It may be a useful imaging tool for patients who cannot undergo joint aspiration because of contraindications or with difficult to aspirate joints, or those who refuse joint aspiration. We also suggest the use of DECT in cases where a definitive diagnosis cannot be made from signs, symptoms, and MSU analysis alone.

Hyperuricemia as a prognostic factor after acute coronary syndrome

BACKGROUND AND AIMS

Many studies have reported the independent association between uric acid and cardiovascular disease, its role as a risk predictor for outcomes in people with acute coronary syndrome remains controversial. This study aims to assess the association between hyperuricemia and medium/long-term clinical outcomes in people with acute coronary syndrome and determine whether adding hyperuricemia to the GRACE score improves its predictive capability.

METHODS

This cohort study included patients admitted for acute coronary syndrome between 2008 and 2013. Outcomes were cardiovascular and total mortality, and major cardiovascular events. We used a multivariate model to adjust for potential confounding covariates and presented event rates with Kaplan-Meier curves. After adding hyperuricemia to the GRACE score, we compared scores from the reclassification table and the net reclassification improvement.

RESULTS

1119 participants were included and followed-up for a mean of 36 months. Multivariate models showed hyperuricemia was independently associated with higher cardiovascular mortality (HR:1.91; 95% CI:1.32-2.76; p < 0.01), higher all-cause mortality (HR:1.59; 95% CI:1.18-2.15; p < 0.01) and higher major cardiovascular event rates (HR:1.36; 95% CI:1.11-1.67; p < 0.01). The hyperuricemia addition to GRACE score led to reclassifying 26% of the participants, and net reclassification improvement was 34%. However, the area under the curve increase was 0.009 and not statistically significant (p > 0.05).

CONCLUSIONS

Hyperuricemia is associated with higher medium/long-term mortality and major cardiovascular event rates in patients following acute coronary syndrome. The addition of hyperuricemia to the GRACE score seems to improve risk classification but the discrimination of the new predictive model did not change. Hyperuricemic patients had higher all-cause mortality in medium and high-risk score categories.

Elevated serum uric acid and risk of cardiovascular or all-cause mortality in people with suspected or definite coronary artery disease: A meta-analysis

BACKGROUND AND AIMS

Serum uric acid (SUA) has been recognized as an independent risk factor for mortality in the general population. We performed this meta-analysis to determine whether elevated SUA levels are associated with greater risk of cardiovascular or all-cause mortality in people with suspected or definite coronary artery disease (CAD).

METHODS

The Pubmed and Embase databases were searched up to April 1, 2016 for the longitudinal studies that investigated the association between the elevated SUA and cardiovascular or all-cause mortality risk in people with suspected or definite CAD. Pooled adjusted risk ratio (RR) and corresponding 95% confidence interval (CI) were calculated for the highest vs. the lowest SUA category or each 1 mg/ml SUA rise.

RESULTS

Nine studies enrolling 25,229 participants were included in the analyses. The highest vs. lowest SUA category was associated with greater risk of cardiovascular mortality (RR 2.09; 95% CI: 1.45-3.02) and all-cause mortality (RR 1.80; 95% CI: 1.39-2.34) after adjustment for potential confounders in a random effects model. Moreover, each 1 mg/ml SUA rise significantly increased by 12% cardiovascular mortality and by 20% all-cause mortality.

CONCLUSIONS

Elevated SUA levels are strongly and independently associated with greater risk of cardiovascular and all-cause mortality in people with suspected or definite CAD.

Relation of Lipid Content of Coronary Plaque to Level of Serum Uric Acid

Elevated serum uric acid (SUA) level is known to be a prognostic factor in patients with acute coronary syndrome (ACS). However, the pathogenesis of the relation between SUA level and coronary plaque characteristics has not been fully evaluated. The aim of this study was to investigate the relation between SUA level and plaque composition of nonculprit lesions in patients with ACS. A total of 81 patients with ACS who underwent intravascular ultrasound (IVUS)-guided percutaneous coronary intervention were included. They were classified into 3 groups according to tertiles of SUA level. Using integrated backscatter (IB)-IVUS system, tissue components were classified into 4 categories: calcium deposits, dense fibrosis, fibrosis, and lipid. Tertiles of SUA level were as follows: low tertile <5.0 mg/dl; intermediate tertile 5.0 to 6.4 mg/dl; and high tertile >6.4 mg/dl. There was a trend toward greater vessel volume in the high tertile group than in the low and intermediate tertile groups (19.4 ± 3.7 vs 17.4 ± 4.4 vs 16.7 ± 4.1 mm(3)/mm, p = 0.05). There was no significant difference in lumen volume between the 3 groups. Plaque volume was significantly greater in the high than in the low tertile group (8.6 ± 2.4 vs 6.7 ± 2.2 mm(3)/mm, p = 0.01). IB-IVUS analysis demonstrated greater lipid (59.1 ± 9.1% vs 49.7 ± 10.9% vs 51.1 ± 9.3%, p = 0.001) and less fibrous components (36.8 ± 7.8% vs 44.3 ± 7.8% vs 43.2 ± 6.7%, p <0.001) in the high than in the low and intermediate tertile groups. Multivariate analysis showed high SUA as an independent predictor of increasing lipid volume. In conclusion, elevated SUA level is associated with greater lipid content of coronary plaque in patients with ACS than in patients with normal levels.

Biomarkers of oxidative stress study VI. Endogenous plasma antioxidants fail as useful biomarkers of endotoxin-induced oxidative stress

This is the newest report in a series of publications aiming to identify a blood-based antioxidant biomarker that could serve as an in vivo indicator of oxidative stress. The goal of the study was to test whether acutely exposing Göttingen mini pigs to the endotoxin lipopolysaccharide (LPS) results in a loss of antioxidants from plasma. We set as a criterion that a significant effect should be measured in plasma and seen at both doses and at more than one time point. Animals were injected with two doses of LPS at 2.5 and 5 µg/kg iv. Control plasma was collected from each animal before the LPS injection. After the LPS injection, plasma samples were collected at 2, 16, 48, and 72 h. Compared with the controls at the same time point, statistically significant losses were not found for either dose at multiple time points in any of the following potential markers: ascorbic acid, tocopherols (α, δ, γ), ratios of GSH/GSSG and cysteine/cystine, mixed disulfides, and total antioxidant capacity. However, uric acid, total GSH, and total Cys were significantly increased, probably because LPS had a harmful effect on the liver. The leakage of substances from damaged cells into the plasma may have increased plasma antioxidant concentrations, making changes difficult to interpret. Although this study used a mini-pig animal model of LPS-induced oxidative stress, it confirmed our previous findings in different rat models that measurement of antioxidants in plasma is not useful for the assessment of oxidative damage in vivo.

Predictors of Chronic Total Occlusion in Nonculprit Artery in Patients With Acute Coronary Syndrome

Chronic total occlusion (CTO) in a noninfarct-related artery (non-IRA) is an independent predictor of mortality in acute coronary syndrome (ACS). Mean platelet volume (MPV) and serum uric acid (SUA) are associated with cardiovascular events in ACS. We investigated the relationship between the presence of non-IRA-CTO with MPV and SUA levels in patients with ACS. Patients (n = 1024) who underwent urgent coronary angiography for ACS were included in this study. Blood samples were drawn on admission. Patients were categorized into 2 groups: non-IRA-CTO (−) and non-IRA-CTO (+). The MPV and SUA levels on admission were significantly higher in the non-IRA-CTO (+) group than in the non-IRA-CTO (−) group ( P < .001). At multivariate analysis, MPV (odds ratio [OR]: 4.705, P < .001) and SUA (OR: 2.535, P < .001) were independent predictors of non-IRA-CTO together with age, hemoglobin, ejection fraction, and non-ST-segment elevation ACS. The MPV and SUA levels were significant and independent predictors for the presence of non-IRA-CTO in patients with ACS.