Reference interval establishment and correlation research of urine thromboxane metabolites: Unveiling new possibilities in platelet activation

BACKGROUND

Thromboxane metabolites could indirectly reflect platelet activation, among which 11-dehydro-thromboxane B2 (11dhTxB2) and 11-dehydro-2, 3-dinor thromboxane B2 (11dh23dinorTxB2) are two stable metabolites that are abundant in urine, and both are closely related to disease progression and drug use. However, most clinical application studies have focused on the single indicator of 11dhTxB2. We propose an LC-MS/MS method suitable for routine clinical screening with simultaneous determination of both metabolites and conduct preliminary studies in different populations.

METHODS AND RESULTS

The thromboxane metabolites were extracted by liquid-liquid extraction and determined by LC-MS/MS. Reference intervals (RI) were established in 333 healthy adults and validated in 25 patients with coronary atherosclerosis (CA). This LC-MS/MS method was over a wide quantitative range (0.1-10 μmol/L), the imprecision and accuracy were 5.2 %-11 % and 89.3 %-106.5 %, and was suitable for clinical routine quantitative screening. The 95th percentile RI of unire 11dhTxB2 was 1220 (95 % CI: 1048, 1376) pg mg Cr -1, for 11dh23dinorTxB2, RI was 908 (95 % CI: 821, 1102) pg mg Cr -1. For the first time, we found a significant correlation between 11dhTxB2 and 11dh23dinorTxB2 in both healthy adults (r = 0.67, P < 0.001) and CA patients (r = 0.77, P < 0.001).

CONCLUSION

The establishment of RI provides a reference for diseases related to platelet activation and the use of drugs, and the first discovery of the correlation between 11dhTxB2 and 11dh23dinorTxB2 in urine provides a new possibilitie for the diagnostic and prognostic of cardiovascular diseases.

Effect of 1,5-anhydroglucitol levels on culprit plaque rupture in diabetic patients with acute coronary syndrome

BACKGROUND

Postprandial hyperglycemia was reported to play a key role in established risk factors of coronary artery diseases (CAD) and cardiovascular events. Serum 1,5-anhydroglucitol (1,5-AG) levels are known to be a clinical marker of short-term postprandial glucose (PPG) excursions. Low serum 1,5-AG levels have been associated with occurrence of CAD. However, the relationship between 1,5-AG levels and coronary plaque rupture has not been fully elucidated. The aim of this study was to evaluate 1,5-AG as a predictor of coronary plaque rupture in diabetic patients with acute coronary syndrome (ACS).

METHODS

A total of 144 diabetic patients with ACS were included in this study. All patients underwent intravascular ultrasound examination, which revealed 49 patients with plaque rupture and 95 patients without plaque rupture in the culprit lesion. Fasting blood glucose (FBG), hemoglobin A_1c (HbA_1c) and 1,5-AG levels were measured before coronary angiography. Fasting urinary 8-iso-prostaglandin F_2α (8-iso-PGF_2α) level was measured and corrected by creatinine clearance.

RESULTS

Patients with ruptured plaque had significantly lower serum 1,5-AG levels, longer duration of diabetes, higher HbA_1c and FBG levels than patients without ruptured plaque in our study population. In multivariate analysis, low 1,5-AG levels were an independent predictor of plaque rupture (odds ratio 3.421; P = 0.005) in diabetic patients with ACS. The area under the receiver-operating characteristic curve for 1,5-AG (0.658, P = 0.002) to predict plaque rupture was superior to that for HbA_1c (0.587, P = 0.087). Levels of 1,5-AG were significantly correlated with urinary 8-iso-prostaglandin F_2α levels (r = - 0.234, P = 0.005).

CONCLUSIONS

Serum 1,5-AG may identify high risk for coronary plaque rupture in diabetic patients with ACS, which suggests PPG excursions are related to the pathogenesis of plaque rupture in diabetes.

Differential urinary proteins to diagnose coronary heart disease based on iTRAQ quantitative proteomics

Coronary artery disease (CAD) is a manifestation of systemic atherosclerotic disease. It is assessed by intervention or traditional scoring risk factors. Diagnosis is limited by inaccurate and invasive methods. Developing noninvasive methods to screen for the risk of CAD is a major challenge. We aimed to identify urinary proteins associated with CAD. We utilized iTRAQ labeling followed by 2D LC-MS/MS to compare the urinary proteome of CAD patients to healthy cohorts. The multiple reaction monitoring (MRM) was used to verify the differential proteins. ROC analysis based on MRM data was used to evaluate the diagnostic application. A total of 876 proteins were quantified, and 100 differential proteins were found. Functional analysis revealed that the differential proteins were mainly associated with Liver X Receptor/Retinoid X Receptor (LXR/RXR) pathway activation, atherosclerosis signaling, production of nitric oxide and reactive oxygen species, and the top upstream regulator of the differential proteins by IPA analysis indicated to the APOE. Nineteen differential proteins were verified by MRM analysis. ROC based on MRM data revealed that the combination of two proteins (APOD and TFF1) could diagnose CAD with 85% sensitivity and 99% specificity (AUC 0.95). The urinary proteome might reflect the pathophysiological changes in CAD and be used for the clinical study of CAD.

Urinary 8-iso-prostaglandin F2α as a risk marker for the vulnerability of culprit plaque in diabetic patients with stable coronary artery disease

We evaluated the association of urinary excretion of 8-iso-prostaglandin F_2α (8-iso-PGF_2α) with the vulnerability of culprit lesions in 156 age- and sex-matched diabetic stable coronary artery disease (CAD) patients with or without thin-capped fibroatheroma (TCFA) identified by iMAP intravascular ultrasound. Fasting urinary 8-iso-PGF_2α level was measured and corrected by creatinine clearance. Compared to non-TCFA group, patients with TCFA had higher urinary 8-iso-PGF_2α levels [114.6 (71.1, 181.5) vs. 83.0 (63.2, 138.2) pmol/mmolCr, P = 0.012]. Urinary 8-iso-PGF_2α level was positively correlated with percent necrotic volume of culprit lesion (r = 0.218, P = 0.006). High urinary 8-iso-PGF_2α level (OR 2.941, P = 0.009) was independently associated with the presence of TCFA and displayed a significant value in predicting TCFA plaques in study patients. The current study indicated that urinary 8-iso-PGF_2α may be an important surrogate marker for the vulnerability of culprit lesion in diabetic patients with CAD.

Association between elevated urinary levels of kidney injury molecule type 1 and adverse cardiovascular events at 12 months in patients with coronary artery disease

INTRODUCTION Contrast‑induced nephropathy is associated with worse prognosis in patients with coronary artery disease (CAD); however, the prognostic role of urinary biomarkers of renal injury has not been fully established. OBJECTIVES We evaluated the clinical utility of urinary biomarkers for the prediction of major adverse cardiac and cerebrovascular events (MACCEs) in patients undergoing coronary angiography. PATIENTS AND METHODS This prospective study included 95 consecutive patients with stable and unstable CAD (men, 69.5%; median age, 65 years), referred for coronary angiography and monitored for MACCEs during 12-month follow-up. MACCEs were defined as cardiovascular death, myocardial infarction, myocardial revascularization, or stroke. Urine samples were collected 24 hours before and 6 hours after coronary angiography and assayed for kidney injury molecule type 1 (KIM-1), interleukin 18, liver fatty acid-binding protein, and renalase, using an enzyme-linked immunosorbent assay. The results were adjusted for urinary creatinine concentration. RESULTS MACCEs occurred in 10 patients (10.5%). These patients had a higher rate of postprocedural contrast‑induced acute kidney injury than patients without MACCEs (30.0% vs 7.1%, P = 0.02), higher median SYNTAX score (25.5 points vs 11.5 points, P = 0.04), higher postprocedural KIM‑1 concentrations (0.45 ng/mg vs 0.21 ng/mg, P = 0.03), and a larger absolute increase of urinary KIM‑1 levels (ΔKIM‑1; 0.41 ng/mg vs 0.10 ng/mg, P = 0.01). Preprocedural values of KI M‑‑1 and other biomarkers were comparable between groups. Patients with ΔKIM‑1 levels above the 75th percentile had worse 12‑month prognosis (P = 0.0004). ΔKIM‑1 levels were an independent predictor of 12‑month MACCEs (P = 0.001). MACCEs were accurately predicted by ΔKIM‑1 levels exceeding 0.093 ng/mg (area under the curve, 0.752; P = 0.0001). CONCLUSIONS Excessive increase of urinary KIM‑1 levels after coronary angiography may help identify CAD patients with poor 12‑month prognosis.

Urine Cotinine level with smoking history predicts a risk of coronary artery calcification

We investigated whether urine cotinine level, alone or combined with smoking status and cumulative smoking amount, could predict coronary calcium (CAC) score increase over time. The study population included 10,980 subjects. We analysed an association between CAC score increase over time and single or combined smoking-related factors. Urine cotinine level of ≥100 ng/mL, current or ex-smokers, and cumulative smoking amount of ≥1 pack-years (PY) showed significantly higher odds ratios (ORs) for CAC score increase over time. A combination of current smokers with >10 PY and urine cotinine level of ≥100 ng/mL showed the highest OR. Irrespective of smoking status and cumulative smoking amount, all combinations with urine cotinine of ≥100 ng/mL showed higher ORs than other combinations with urine cotinine level of <100 ng/mL. Urine cotinine levels can be useful to predict coronary artery calcification and encourage smokers to quit smoking.

Leukotriene biosynthesis in coronary artery disease. Results of the Leukotrienes and Thromboxane In Myocardial Infarction (LTIMI) study

INTRODUCTION Leukotrienes (LTs) may be involved in atherosclerosis and may contribute to cardiovascular outcomes in CAD. OBJECTIVES    We aimed to compare the baseline LT production in patients with stable CAD (sCAD) and myocardial infarction (MI), and to assess whether an increased LT production is associated with major adverse cardiovascular events (MACEs) at 1 year after MI. PATIENTS AND METHODS    LTIMI (Leukotrienes and Thromboxane In Myocardial Infarction) was a single‑center, prospective, observational study of patients with stable sCAD and MI. Urinary leukotriene E4 (LTE4) levels were measured on admission, at 1 month, and at 1 year, using high‑performance liquid chromatography tandem mass spectrometry. RESULTS    Of the 404 patients screened, 289 were enrolled (110 with sCAD and 179 with MI; mean [SD] age, 63.9 [10.9] years). Patients with MI had higher median (interquartile range [IQR]) levels of log‑transformed LTE4 (logLTE4) than those with sCAD (4.74 pg/mg creatinine [4-5.45] vs 4.51 pg/mg creatinine [3.99 4.86], respectively; P <0.001). Median (IQR) logLTE4 levels in patients with MI significantly decreased at 1 month to 4.37 pg/mg creatinine (3.81-4.95), and at 1 year to 4.16 pg/mg creatinine (3.55-4.85). The baseline urinary logLTE4 levels were similar in patients with MACEs and those without MACEs (median [IQR], 4.78 pg/mg creatinine [4.01-5.56]) and 4.68 pg/mg creatinine [3.97-5.28], respectively; P >0.05). Multiple regression showed no relation between LTE4 levels and the incidence of MACEs. CONCLUSIONS    LT production assessed by urinary LTE4 excretion is higher in patients with MI than in those with sCAD; however, LTE4 levels at baseline do not differ between patients with and without MACEs at 1 year after MI.

The kynurenine:tryptophan ratio as a predictor of incident type 2 diabetes mellitus in individuals with coronary artery disease

AIMS/HYPOTHESIS

The tryptophan metabolite kynurenine has potent immune modulatory and vasoactive properties. Experimental data implicate kynurenine in obesity-related morbidities. Epidemiological studies are, however, sparse. We evaluated associations of the plasma and urine kynurenine:tryptophan ratio (KTR) to incident type 2 diabetes.

METHODS

We followed 2519 individuals with coronary artery disease (CAD; 73.1% men) without diabetes at baseline for a median of 7.6 years, during which 173 (6.9%) new incidences of type 2 diabetes were identified. Multivariate Cox regression analyses were applied to investigate the prospective relationships of plasma and urine KTR with new onset type 2 diabetes.

RESULTS

At inclusion, mean (SD) age was 61.3 (10.4) years, BMI was 25.9 (3.71) kg/m2 and median (interquartile range) HbA1c was 5.6% (5.0%-6.0%) (38 [31-42] mmol/mol). Plasma KTR was not significantly related to type 2 diabetes risk. By contrast, urine KTR showed a strong positive association. Comparing quartile 4 with quartile 1, the HRs (95% CIs) were 2.59 (1.56, 4.30) and 2.35 (1.39, 3.96) in the age- and sex-adjusted and multivariate models, respectively.

CONCLUSIONS/INTERPRETATION

Urine KTR is a strong predictor of incident type 2 diabetes in individuals with CAD. Potential clinical implications and possible pathogenic roles of renal kynurenine excretion in type 2 diabetes development should be further elucidated.

Estimated GFR and Subsequent Higher Left Ventricular Mass in Young and Middle-Aged Adults With Normal Kidney Function: The Coronary Artery Risk Development in Young Adults (CARDIA) Study

BACKGROUND

Left ventricular hypertrophy is common and is associated with cardiovascular events and death among patients with known chronic kidney disease. However, the link between reduced glomerular filtration rate (GFR) and left ventricular mass index (LVMI) remains poorly explored among young and middle-aged adults with preserved kidney function. In this study, we examined the association of cystatin C-based estimated GFR (eGFRcys) and rapid decline in eGFR with subsequent LVMI.

STUDY DESIGN

Observational study.

SETTING & PARTICIPANTS

We included 2,410 participants from the Coronary Artery Risk Development in Young Adults (CARDIA) cohort with eGFRcys > 60mL/min/1.73m(2) at year 15 and who had an echocardiogram obtained at year 25.

PREDICTOR

eGFRcys at year 15 and rapid decline in eGFRcys (defined as >3% per year over 5 years from years 15 to 20).

OUTCOME

LVMI measured at year 25.

MEASUREMENTS

We adjusted for age, sex, race, diabetes, body mass index, low- and high-density lipoprotein cholesterol levels, cumulative systolic blood pressure, and albuminuria.

RESULTS

Mean age was 40±4 (SD) years, 58% were women, and 43% were black. After 10 years of follow-up, mean LVMI was 39.6±13.4g/m(2.7). Compared with eGFRcys > 90mL/min/1.73m(2) (n = 2,228), eGFRcys of 60 to 75mL/min/1.73m(2) (n = 29) was associated with 5.63 (95% CI, 0.90-10.36) g/m(2.7) greater LVMI (P = 0.02), but there was no association of eGFRcys of 76 to 90mL/min/1.73m(2) (n = 153) with LVMI after adjustment for confounders. Rapid decline in eGFRcys was associated with higher LVMI compared with participants without a rapid eGFRcys decline (β coefficient, 1.48; 95% CI, 0.11-2.83; P = 0.03) after adjustment for confounders.

LIMITATIONS

There were a limited number of participants with eGFRcys of 60 to 90mL/min/1.73m(2).

CONCLUSIONS

Among young and middle-aged adults with preserved kidney function, eGFRcys of 60 to 75mL/min/1.73m(2) and rapid decline in eGFRcys were significantly associated with subsequently higher LVMI. Further studies are needed to understand the mechanisms that contribute to elevated LVMI in this range of eGFRcys.

Relation of fish oil supplementation to markers of atherothrombotic risk in patients with cardiovascular disease not receiving lipid-lowering therapy

Fish oil supplementation (FOS) is known to have cardiovascular benefits. However, the effects of FOS on thrombosis are incompletely understood. We sought to determine if the use of FOS is associated with lower indices of atherothrombotic risk in patients with suspected coronary artery disease (sCAD). This is a subgroup analysis of consecutive patients with sCAD (n=600) enrolled in the Multi-Analyte, Thrombogenic, and Genetic Markers of Atherosclerosis study. Patients on FOS were compared with patients not on FOS. Lipid profile was determined by vertical density gradient ultracentrifugation (n=520), eicosapentaenoic acid+docosahexaenoic acid was measured by gas chromatography (n=437), and AtherOx testing was performed by immunoassay (n=343). Thromboelastography (n=419), ADP- and collagen-induced platelet aggregation (n=137), and urinary 11-dehydrothromboxane B2 levels (n=259) were performed immediately before elective coronary angiography. In the total population, FOS was associated with higher eicosapentaenoic acid+docosahexaenoic acid content (p<0.001), lower triglycerides (p=0.04), total very low-density lipoprotein cholesterol (p=0.002), intermediate-density lipoprotein cholesterol (p=0.02), and AtherOx levels (p=0.02) but not in patients on lipid-lowering therapy. Patients not on lipid-lowering therapy taking FOS had lower very low-density lipoprotein cholesterol, intermediate-density lipoprotein cholesterol, remnant lipoproteins, triglycerides, low-density lipoprotein cholesterol, AtherOx levels, collagen-induced platelet aggregation, thrombin-induced platelet-fibrin clot strength, and shear elasticity (p<0.03 for all). In clopidogrel-treated patients, there was no difference in ADP-induced aggregation between FOS groups. Patients on FOS had lower urinary 11-dehydrothromboxane B2 levels regardless of lipid-lowering therapy (p<0.04). In conclusion, the findings of this study support the potential benefit of FOS for atherothrombotic risk reduction in sCAD with the greatest benefit in patients not receiving lipid-lowering therapy. Future prospective studies to compare FOS with lipid-lowering therapy and to assess the independent effects of FOS on thrombogenicity are needed.

Clinical proteomics identifies urinary CD14 as a potential biomarker for diagnosis of stable coronary artery disease

Inflammation plays a key role in coronary artery disease (CAD) and other manifestations of atherosclerosis. Recently, urinary proteins were found to be useful markers for reflecting inflammation status of different organs. To identify potential biomarker for diagnosis of CAD, we performed one-dimensional SDS-gel electrophoresis followed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Among the proteins differentially expressed in urine samples, monocyte antigen CD14 was found to be consistently expressed in higher amounts in the CAD patients as compared to normal controls. Using enzyme-linked immunosorbent assays to analyze the concentrations of CD14 in urine and serum, we confirmed that urinary CD14 levels were significantly higher in patients (n = 73) with multi-vessel and single vessel CAD than in normal control (n = 35) (P < 0.001). Logistic regression analysis further showed that urinary CD14 concentration level is associated with severity or number of diseased vessels and SYNTAX score after adjustment for potential confounders. Concomitantly, the proportion of CD14+ monocytes was significantly increased in CAD patients (59.7 ± 3.6%) as compared with healthy controls (14.9 ± 2.1%) (P < 0.001), implicating that a high level of urinary CD14 may be potentially involved in mechanism(s) leading to CAD pathogenesis. By performing shotgun proteomics, we further revealed that CD14-associated inflammatory response networks may play an essential role in CAD. In conclusion, the current study has demonstrated that release of CD14 in urine coupled with more CD14+ monocytes in CAD patients is significantly correlated with severity of CAD, pointing to the potential application of urinary CD14 as a novel noninvasive biomarker for large-scale diagnostic screening of susceptible CAD patients.

Analysis of urinary methylated nucleosides of patients with coronary artery disease by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry

RATIONALE

In recent years, methylated nucleosides have been considered to be potential biomarkers to human diseases. The early diagnosis of coronary artery disease (CAD) is an unsolved problem in clinical cardiology. The aim of our study is to evaluate whether urinary methylated nucleosides can serve as useful biomarkers for CAD.

METHODS

A solid-phase extraction (SPE) column was used for extraction and purification of methylated nucleosides in urine, and high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC/ESI-MS/MS) was employed for specific, sensitive and rapid determination of the urinary methylated nucleosides from patients with cardiac events.

RESULTS

We have analyzed six methylated nucleosides (N(3)-methylcytidine, N(1)-methyladenosine, N(6)-methyladenosine, N(2)-methylguanosine, N(1)-methylguanosine and N(2),N(2)-dimethylguanosine) in urine from 51 patients with CAD and 25 non-CAD controls by HPLC/ESI-MS/MS using selective reaction monitoring (SRM). Our results have shown that there were significant differences in the N(6)-methyladenosine levels from the patients and the non-CAD controls in the urine analyzed.

CONCLUSIONS

The results have indicated that HPLC/ESI-MS/MS is a highly specific and sensitive tool to measure urinary methylated nucleosides for analysis of CAD. Our result has revealed that the evaluation of urinary methylated nucleosides might be helpful in the analysis of CAD by liquid chromatography/mass spectrometry. Therefore, this N(6)-methyladenosine is worthy of further studies in the near future.

The relationship between microalbuminuria and isolated coronary artery ectasia

AIM

Coronary artery ectasia (CAE), is at least 1.5 fold dilatation of at least one coronary segment due to congenital or acquired causes. In this study, we aim to investigate the relation of CAE with microalbuminuria, which is a marker of endothelial dysfunction shown to be associated with increased cardiovascular mortality and morbidity.

PATIENTS AND METHODS

Patients with CAE detected during routine coronary angiogram (CAG) and individuals with normal CAG findings have been included in our study. Urine albumin levels were measured by immunoturbidimetric method from samples collected in the morning. Patients with an albumin/creatinine (A/C) ratio less than 0.03 were normal and the ones between values 0.03-0.3 were considered to be microalbuminuric. Patients whose A/C ratios > 0.3 had macroalbuminuria and were excluded.

RESULTS

A total of 105 patients (60 with CAE and 45 with normal CAG) were included in the study. Serum creatinine, low-density lipoprotein cholesterol and homocysteine levels were increased in the CAE group. Urine A/C ratio was 0.036 ± 0.040 in the CAE group and 0.018 ± 0.013 in the controls; the difference was statistically significant (p = 0.002).

CONCLUSIONS

Blood homocysteine levels and urinary albumin levels are significantly increased in patients with CAE when compared to individuals with normal CAG. Microalbuminuria and hyperhomocysteinemia, two markers of endothelial dysfunction might be associated with pathophysiologic processes leading to CAE.

Correlation between microalbuminuria with complexity of coronary artery disease in diabetic patients

The present studies found that microalbuminuria is predictive, independent of classical risk factor of cardiovascular diseases and all causes of mortality in diabetes or hypertension patient groups and in the general population. Coronary angiograms for extent of severe CAD (luminal narrowing 50%) in patients with Diabetes Mellitus (DM) and general population were examined. The study comprised 150 patients undergoing coronary angiography at United Hospital Limited, Dhaka, Bangladesh, (M/F 80/70, mean age 57±11 years). Urine albumin excretion was measured in 24 hours urine samples employing immune precipitation technique. Age-gender distribution of coronary risk factors and microalbuminuria were compared between patient with and without coronary artery disease. As many as 70.5% (106) of patient had coronary artery disease and 29.4%(44) had no coronary lesion. Microalbuminuria was detected at 62.9% in patients with CAD and 8.8% in those without coronary artery lesion (p<0.001). The presence of 1 or 2 vessel CAD showed a linear increase between the groups without microalbuminuria. Patients with microalbuminuria have more severe angiographically detected coronary artery disease than those without microalbuminuria, thus a link can be established independent of other risk factors.

Urine calcium excretion, cardiovascular events, and mortality in outpatients with stable coronary artery disease (from the Heart and Soul study)

We sought to evaluate the association of urine calcium excretion (UCaE), which reflects systemic calcium absorption, with cardiovascular (CV) events and mortality in outpatients with prevalent coronary heart disease (CHD). Calcium supplementation is associated with vascular calcification and adverse CV outcomes in patients with end-stage renal disease. Recent studies have raised concern that this phenomenon may also extend to the general population. However, previous studies have assessed oral calcium intake, which correlates poorly with systemic calcium absorption. We measured UCaE from 24-hour urine collections provided by 903 outpatients who were recruited from 2000 to 2002. We used Cox proportional hazard models to evaluate the association of baseline UCaE with a primary end point of any CV event (myocardial infarction [MI], heart failure, stroke, or CV mortality). During a mean follow-up of 6 ± 3 years, 287 subjects (32%) had a CV event. After multivariate adjustment for demographics, traditional CV risk factors, and kidney function, there was no association between UCaE and the primary end point of any CV event (per 10-mg/day greater UCaE, hazard ratio 1.00, 95% confidence interval 0.98 to 1.02). Evaluation of individual CV outcomes revealed a lower rate of MI with higher UCaE (hazard ratio 0.97, 95% confidence interval 0.94 to 1.00). In conclusion, greater UCaE is not associated with higher overall CV event rates or mortality in outpatients with stable CHD. On the contrary, greater UCaE is associated with a modestly lower rate of MI. These findings suggest that greater systemic calcium absorption does not confer CV harm in outpatients with prevalent CHD.

Urinary albumin excretion rate is correlated with severity of coronary artery disease in elderly type 2 diabetic patients

BACKGROUND

Coronary heart disease is the main complication of type 2 diabetes mellitus; its incidence is closely related to microalbuminuria. The aim of this study was to investigate the correlation between the urinary albumin excretion rate and the incidence and severity of coronary heart disease in elderly type 2 diabetes mellitus patients.

METHODS

A total of 612 hospitalized type 2 diabetes mellitus patients aged 60 years or older, who were given coronary angiography for diagnosis of possible coronary heart disease, participated. Their urinary albumin excretion rate was measured, and the severity of coronary artery stenosis was quantified with the Gensini scoring system to analyze the incidence of coronary heart disease and the severity of coronary artery stenosis. The optimal urinary albumin excretion rate predictive value for coronary heart disease incidence in elderly type 2 diabetes mellitus patients was determined.

RESULTS

The incidence of coronary heart disease, the number of patients with coronary vascular disease and the Gensini scores were significantly different between the microalbuminuria group and the normal albuminuria group (P < 0.05). The urinary albumin excretion rate was independently correlated with the occurrence of coronary heart disease in elderly type 2 diabetes mellitus patients (odds ratio (OR) = 1.058, P < 0.0001, 95% confidence interval (CI): 1.036 - 1.080). Urinary albumin excretion rate and the Gensini score were independently correlated in elderly type 2 diabetes mellitus patients (β = 0.476, P < 0.0001). The best predictive value of urinary albumin excretion rate was 10.45 µg/min for elderly type 2 diabetes mellitus patients. The area under the curve was 0.764, with a sensitivity and specificity of 70.0% and 72.2%, respectively.

CONCLUSIONS

The occurrence of coronary heart disease in elderly type 2 diabetes mellitus patients with microalbuminuria was higher than that in patients with normal albuminuria, and the severity of the disease also increased in patients with microalbuminuria. In elderly type 2 diabetes mellitus patients, urinary albumin excretion rate was positively correlated with the incidence and severity of coronary heart disease and was also an independent factor contributing to coronary heart disease.

Urinary asymmetric dimethylarginine (ADMA) is a predictor of mortality risk in patients with coronary artery disease

BACKGROUND

Asymmetric dimethylarginine (ADMA) causes endothelial dysfunction by inhibiting endothelial nitric oxide synthase. Elevated ADMA plasma levels comprise a major risk factor for coronary artery disease (CAD) and predict coronary events. ADMA is metabolised by dimethylarginine dimethylaminohydrolases (DDAHs) to citrulline and dimethylamine (DMA) and is partly excreted unchanged via the kidney. Unlike circulating ADMA, very little is known about urinary ADMA and DMA concentrations and a predictive value in CAD patients.

METHODS AND RESULTS

Seventy-seven consecutive patients admitted to hospital because of stable angina (mean age 65.9 ± 1.1 years) were enrolled and followed-up for 28 [1-28] months. All patients underwent cardiac catheterization and were divided into patients with no CAD or 1-3-vessel disease (CAD 1-3). Urinary ADMA levels (corrected for creatinine excretion) were lower in severely diseased patients (CAD 3, p<0.05) whereas the DMA/ADMA ratio was significantly increased (p<0.05 CAD 3 vs. CAD 0). In a stepwise multivariate regression analysis the ADMA/creatinine ratio correlated with cardiac function (r=0.5, p<0.0001) and LDL concentrations (r=0.27, p=0.01). A total of 12 patients died during follow-up, 9 due to cardiovascular causes. Importantly, low urinary ADMA concentrations predicted future cardiovascular death (p<0.01) and overall death (p<0.05).

CONCLUSION

In CAD patients low urinary ADMA concentrations are associated with impaired cardiac function and predict cardiovascular as well as all-cause mortality. The potential clinical value of urinary ADMA as a new biomarker for the diagnosis of CAD or cardiac dysfunction is intriguing, but warrants further studies.

Association between documented coronary artery disease and urinary albumin, albumin to creatinine ratio

BACKGROUND

The aim of this study was to investigate whether the amount of urinary albumin concentration (UAC) or urinary albumin to creatinine ratio (UACR) is more strongly associated with angiographically documented coronary artery disease (CAD).

MATERIAL/METHODS

A total of 199 consecutive patients [11 9(60%) male, 80 (40%) female, mean age =57±10] undergoing diagnostic coronary angiography were included in the study. Significant coronary artery disease was defined as a stenosis equal to or above 50% in the main coronary artery or in one of the other branches. UAC and UACR were calculated from the urine. Baseline clinical parameters, UAC and UACR were compared between subjects with and without CAD. Factors predicting CAD were evaluated by multivariate analysis.

RESULTS

Baseline clinical and laboratory characteristics of patients with and without CAD were not different except for a slightly male predominance in patients with CAD. Patients with CAD had significantly higher UACs and UACRs than patients without CAD (32.14±31.27 mg/day vs. 15.61±16.70 mg/day, p=0.01; 9.11±7.42 mg/g vs. 4.80±3.28 mg/g, p=0.009). A positive correlation was found between Gensini score and UACR (p=0.01), whereas no correlation was found between Gensini and UAC. UACR was the only significant parameter for the presence of CAD in the multivariate analysis adjusted for age, sex, other well known CAD risk factors, UAC and UACR.

CONCLUSIONS

Our preliminary results suggest that UACR is more closely associated with angiography documented CAD than is the level of UAC itself, but UACR maybe more significantly associated with angiography documented CAD than with the levels of UAC.

Urinary creatinine excretion rate and mortality in persons with coronary artery disease: the Heart and Soul Study

BACKGROUND

In persons with coronary artery disease, low body mass index is associated with greater mortality; however, it is uncertain whether low muscle mass is a risk factor for mortality in this setting.

METHODS AND RESULTS

In this study, 903 individuals with coronary artery disease provided 24-hour urine collections. We measured urine creatinine and volume and calculated creatinine excretion rate, a marker of muscle mass. Cox proportional-hazards models evaluated the association of creatinine excretion rate with mortality risk. Over a median follow-up of 6.0 years, 232 participants (26%) died. Compared with the highest sex-specific creatinine excretion rate tertile, the lowest tertile (<1068 mg/d in men, <766 mg/d in women) was associated with >2-fold risk of mortality (hazard ratio, 2.30; 95% confidence interval, 1.51 to 3.51) in models adjusted for age, sex, race, cystatin C-based estimated glomerular filtration rate, body mass index, traditional cardiovascular disease risk factors, and C-reactive protein levels. The association was essentially unaltered with further adjustment for physical fitness, left ventricular mass, left ventricular ejection fraction, or fasting insulin and glucose levels.

CONCLUSIONS

Lower creatinine excretion rate is strongly associated with mortality in outpatients with coronary artery disease, independently of conventional measures of body composition, kidney function, and traditional coronary artery disease risk factors. Future studies should determine whether low creatinine excretion rate may be a modifiable risk factor for mortality among persons with coronary artery disease, potentially through resistive exercise training or nutrition interventions.

The relationship between microalbuminuria and the presence and extent of coronary atherosclerosis

OBJECTIVE

To evaluate the relationship between microalbuminuria (MA) and the presence and extent of coronary artery disease (CAD).

METHODS

Four hundred and two consecutive patients were divided into 4 groups based on the presence of diabetes mellitus (DM) and MA: DM(+)/MA(+), DM(+)/MA(-), DM(-)/MA(+), and DM(-)/MA(-). Severity of CAD was assessed by the Gensini scoring system.

RESULTS

The Gensini score was 57 +/- 38.2 vs 16.5 +/- 19.5 (P < .001) in the DM(+)/MA(+) and DM(+)/MA(-) groups and 45 +/- 39.8 vs 9.9 +/- 16.6 (P < .001) in the DM(-)/MA(+) and DM(-)/MA(-) groups. Spearman correlation analysis demonstrated a positive relation between urine albumin/creatinine ratio (ACR) and extent of CAD both in the diabetic and nondiabetic patients (r = .584, P = .001; r = .545, P = .001). Microalbuminuria was found to be an independent predictor for the presence (OR for MA: 3.728; 95% CI, 1.931-7.196; P < .001) and severity of CAD (P < .001, beta = .563).

CONCLUSION

A strong relationship between MA and the severity of CAD was reported.

Chromium status and glucose tolerance in Saudi men with and without coronary artery disease

Chromium deficiency is associated with impaired glucose tolerance (IGT) and dyslipidemia. Hence, the objective of the current study was to investigate chromium status among Saudi men with and without established cardiovascular disease (CVD) and its relationship to glucose tolerance, lipid profile and other established CVD risk factors. We measured serum and urine chromium concentrations, fasted lipid profile, plasma glucose, and serum lipid peroxide in 130 Saudi men with an established history of myocardial infarction and 130 age-matched controls without established CVD. Patients with established CVD had higher serum triglycerides (p < 0.05) and plasma glucose (p < 0.0001) and lower serum and urinary chromium concentrations (p < 0.0001) than controls. Serum chromium was inversely correlated with plasma glucose among cases and controls (r = -0.189, p < 0.05 and r = -0.354, p < 0.00001, respectively). Plasma glucose (OR 1.127, CI 1.0-1.269, p < 0.05), serum chromium (OR 0.99, CI 0.985-0.995, p < 0.0001), and urinary chromium (OR 0.988, CI 0.981-0.995, p < 0.001) were independently associated with the presence of established coronary disease applying this model. While chromium metabolism appears to be altered in individuals with CVD, it is unclear whether chromium supplementation would be effective in CVD prevention among patients with IGT. This would need to be tested in long-term outcome trials.

Significance of urinary liver-fatty acid-binding protein in cardiac catheterization in patients with coronary artery disease

OBJECTIVES

We investigated the significance of urinary liver fatty acid-binding protein (U-L-FABP) monitoring during cardiac catheterization in patients with cardiovascular disease (CVD). Methods The subjects included 27 consecutive patients with stable angina (SAP group) or acute coronary syndrome (ACS group) who had undergone successful percutaneous coronary intervention (PCI), and 12 patients were also enrolled as controls (C group). Urinary and serum parameters were measured immediately before and after and 1 day after PCI.

RESULTS

The ratio of U-L-FABP to U-creatinine (U-Cr) (U-L-FABP/U-Cr) in the ACS group was significantly higher than those in both the SAP and C groups before PCI. In addition, none of the patients in the SAP group showed contrast-induced nephropathy (CIN) based on the levels of serum (S)-Cr and U-L-FABP/U-Cr after PCI. Although none of the patients in the ACS group showed CIN according to S-Cr, the level of U-L-FABP/U-Cr was continuously high throughout the study period. Moreover, since there were significant differences in U-L-FABP/U-Cr, U-N-acetyl-beta-D-glucosaminidase, S-uric acid and % medication with calcium channel blockers before PCI between the ACS and SAP groups, a multiple regression analysis was performed using these parameters. It showed that U-L-FABP/U-Cr was most closely associated with the classification of SAP and ACS (p<0.0001). The cut-off level for the greatest sensitivity and specificity for U-L-FABP for the diagnosis of ACS was 13.4 microg/g. Cr in all subjects (sensitivity 0.800, specificity 0.963).

CONCLUSIONS

To the best of our knowledge, this is the first report indicating that the measurement of U-L-FABP can be beneficial for in the diagnosis of ACS.

High sensitive C-reactive protein, adiponectin, and urine albumin excretion rate in Chinese coronary artery disease patients with different glucose tolerance status

BACKGROUND

Serum high sensitive C-reactive protein (hs-CRP), adiponectin levels and urine albumin excretion rate (UAER) are probably associated with inflammation and atherosclerosis. The aim of this study was to determine the three markers in coronary artery disease (CAD) subjects with different glucose tolerance status in a Chinese population and further explore the levels of the three markers in these subjects and the possible association of these markers with CAD risk factors and the severity of CAD as well.

METHODS

A total of 242 subjects with angiographically documented CAD were recruited, and then assigned to three groups: the normal glucose tolerance (NGT) + CAD group, including 100 CAD patients with NGT; the impaired glucose tolerance (IGT) + CAD group, 40 CAD patients with IGT; the type 2 diabetes mellitus (T2DM) + CAD group, 102 CAD patients with T2DM. Serum hs-CRP, adiponectin levels as well as UAER were measured in all subjects.

RESULTS

Serum hs-CRP levels were increased in the T2DM + CAD group compared with the NGT + CAD group (4.71 +/- 2.59) vs (3.60 +/- 2.46) mg/L, P = 0.037. Serum adiponectin levels were gradually decreased from the NGT + CAD to IGT + CAD to T2DM + CAD groups, (5.99 +/- 1.84), (5.82 +/- 1.72) and (4.65 +/- 1.71) mg/L, P = 0.002 and 0.040 for NGT + CAD and IGT + CAD groups vs T2DM + CAD group, respectively. While the UAER was gradually increased from the NGT + CAD to IGT + CAD to T2DM + CAD groups, (6.42 +/- 2.51), (6.89 +/- 2.94) and (15.03 +/- 4.22) microg/min (P < 0.001) for NGT + CAD and IGT + CAD groups vs T2DM + CAD group. Multiple linear stepwise regression analysis showed that waist-hip ratio (WHR) and low density lipoprotein cholesterol (LDL-C) were the significant determinants of serum hs-CRP levels; triglyceride (TG), high density lipoprotein cholesterol (HDL-C), age, WHR, T2DM, 2-hour serum insulin (2hINS), sex, and apolipoprotein B were the significant determinants of serum adiponectin levels; and systolic blood pressure (SBP), T2DM, and hemoglobin A1c (HbA1c) were the significant determinants of UAER in all subjects (R(2) = 0.070, 0.352, and 0.214, respectively). However, no significant correlation was seen for hs-CRP, adiponectin and UAER with the severity of CAD. Hs-CRP levels were significantly correlated with UAER.

CONCLUSIONS

There was a trend of increased serum hs-CRP levels from the NGT + CAD to IGT + CAD to T2DM + CAD groups, though it only showed significance in the T2DM + CAD group compared with the NGT + CAD group. Serum adiponectin levels were decreased and UAER was increased from the NGT + CAD to IGT + CAD to T2DM + CAD groups. Increased UAER and serum hs-CRP, and decreased adiponectin levels were associated with traditional CAD risk factors but failed to be correlated with the severity of CAD. Hs-CRP levels were significantly correlated with UAER.

Urinary 8-isoprostane levels can indicate the presence, severity and extent of angiographic coronary artery disease

BACKGROUND

Atherosclerotic coronary artery disease is the leading cause of death worldwide. Oxidative stress is one of the key elements in the pathogenesis of atherosclerosis. Isoprostanes are established markers of oxidative stress. The aim of this study was to investigate the association of urinary 8-isoprostane levels with the presence and severity of coronary artery disease (CAD) assessed by a validated scoring system.

METHOD

Urinary 8-isoprostane levels were measured in 100 consecutive patients scheduled for coronary angiography. Extent and severity of CAD were assessed by modified Gensini scores.

RESULTS

In patients with CAD, 8-isoprostane levels were higher (P < 0.001) than in patients without CAD (68.75 +/- 5.5 vs. 38.27 +/- 3.7 pg/ml). The levels of 8-isoprostane correlated with the number of risk factors (P < 0.001) and significantly increased in relation with the number of diseased vessels (P < 0.001). A significant (P < 0.001) correlation was found between 8-isoprostane levels and Gensini scores (r = 0.496), and a stepwise elevation in 8-isoprostane levels was observed across the increasing tertiles of the Gensini scores (P < 0.001). The multivariate logistic regression analysis revealed that 8-isoprostane was an independent predictor (odds ratio: 7.19 and P = 0.007) associated with angiographic CAD.

CONCLUSION

These results confirm the role of oxidative stress in the atherosclerotic process. Urinary 8-isoprostane levels reflect the extent and severity of CAD and they may provide additional information for risk assessment in patients with suspected CAD.

Determination of microalbuminuria in hypertensive patients and in patients with coronary artery disease

BACKGROUND

The normal 24-hour albumin excretion rate is of 20 mg. A persistent rate of 30 to 300 mg/day is called microalbuminuria and is related to a higher prevalence of cardiovascular disease.

OBJECTIVE

1) To determine the prevalence of microalbuminuria in a group of hypertensive patients and in a group of patients with coronary artery disease; 2) To determine the relationship between the presence of microalbuminuria and hypertension, diabetes mellitus, dyslipidemia, smoking and obesity.

METHODS

The presence of microalbuminuria in a group of hypertensive patients (73 individuals) and in a group of patients with coronary artery disease (39 individuals) was determined and compared with a control group (43 individuals). Microalbuminuria was defined as an albumin/creatinine ratio higher than 30 and lower than 300 in a spot morning urine sample. The chi-square test and the Fishers exact test were used in the statistical analysis.

RESULTS

Microalbuminuria was present in 9.5% of the hypertensive individuals and in 33% of the patients with coronary artery disease, and was absent in individuals of the control group. When the occurrence of microalbuminuria was analyzed according to the different clinical parameters, regardless of the group involved, a statistically significant correlation was found with age, diabetes and dyslipidemia.

CONCLUSION

1) The prevalence of microalbuminuria in hypertensive individuals is high, and is even higher in patients with coronary artery disease; 2) There is a correlation of the presence of microalbuminuria with age, diabetes and dyslipidemia.

[Association of microalbuminuria and fasting insulin levels with presence and severity of coronary artery disease in non-diabetic cases]

OBJECTIVE

In this study, we aimed to determine the relation of presence and severity of coronary artery disease with microalbuminuria, fasting insulin levels and the classical risk factors in non-diabetic patients.

METHODS

We enrolled 100 non-diabetic patients that had an indication for coronary angiography. Group 1 consisted of 55 patients with coronary artery disease, and 45 patients without coronary artery disease were included in Group 2. The study was cross-sectional and case-controlled. In all patients 24-hour microalbuminuria, serum total, high density lipoprotein (HDL), low density lipoprotein (LDL) cholesterol and lipoprotein a, triglyceride, fasting blood sugar levels were obtained. Fasting insulin levels were determined and routine urinary tests were performed. Gensini scoring was done for determination of the severity of coronary artery disease. Statistical analysis was performed using unpaired t test, Mann-Whitney U test, Chi-square test, ROC analysis and multiple logistic regression analysis.

RESULTS

Microalbuminuria levels (p<0.001), fasting insulin levels (p<0.001), mean age (p=0.01), pulse pressure (p=0.014), LDL cholesterol levels (p=0.004), lipoprotein a levels (p<0.001) were significantly higher and HDL cholesterol levels were significantly lower (p=0.015) in Group 1 compared to the Group 2. Male gender was more frequent in Group 1 (p<0.001). With cut-off values defined by ROC analysis microalbuminuria (18 microgr/min, sensitivity: 91%, specificity: 45%, area under the curve: 0.790, 95% CI 2.43-15.96, p<0.001) increased probability of coronary artery disease by 6.2-fold and fasting insulin level higher than 10 microIU/ml by 11 folds at multivariate logistic regression analysis. When the cases were evaluated according to the Gensini scoring there was a significant association of coronary artery disease and microalbuminuria (r=0.52, p<0.001).

CONCLUSION

We concluded that in non-diabetic cases microalbuminuria and increased fasting insulin levels were predictors of presence and the severity of coronary artery disease and can be suggested as risk factors.

Screening for aspirin resistance in stable coronary artery patients by three different tests

BACKGROUND

Aspirin (ASA) failure to inhibit in vitro platelet function had been termed ASA resistance. The prevalence of this phenomenon as measured with different platelet function tests varies widely among studies.

OBJECTIVES

In this study, we propose to determine the prevalence of ASA non-responsiveness in stable coronary artery patients using three different tests.

PATIENTS AND METHODS

One hundred ninety-one patients with a stable coronary artery disease and receiving secondary ASA prophylaxis (250 mg/day) were tested. For each patient the ASA-induced platelet inhibition was determined using three different tests: Ivy Bleeding time (BT), collagen/epinephrine closure time (CEPI-CT; PFA-100, Dade-Behring) and urinary 11-dehydrothromboxane B2 (uTxB2) excretion level. The agreement between these tests was evaluated by kappa statistics test.

RESULTS

The prevalence of biological ASA resistance was 15.7% (n=30), 20.4% (n=39) and 24.6% (n=47) by BT, PFA-100 and UTxB2, respectively. Only fourteen patients (7.3%) were non-responders for two tests: 6 (3.1%) BT/ PFA-100; 1 (0.5%) BT/UTxB2; 7 (3.7%) PFA-100/UTxB2). A poor agreement was found between these three methods and only 3 patients were resistant with all the tests (1.6%).

CONCLUSION

The lack of agreement supposed that different types of aspirin resistance exist. Thus, combination of two tests or more could be a primary solution for a better identification of ASA resistant patients. This hypothesis must be confirmed by a large-scale randomized study with clinically well-defined endpoints.

Comparison of intravascular ultrasound and quantitative coronary angiography for the assessment of coronary artery disease progression

BACKGROUND

The relative merits of quantitative coronary analysis (QCA) and intravascular ultrasound (IVUS) for the assessment of progression/regression in coronary artery disease are uncertain. To explore this subject further, we analyzed the angiographic and IVUS data derived from a contemporary clinical trial population.

METHODS AND RESULTS

We investigated the relationships between QCA and IVUS at single time points (n=525) and also for the changes over time (n=432). QCA and IVUS data underwent central laboratory analyses. Statistically significant correlations were observed between the QCA coronary artery score and the IVUS-derived lumen volume (r=0.65, P<0.0001) and total vessel volume (r=0.55, P<0.0001) and between the QCA cumulative coronary stenosis score and percent atheroma volume on IVUS (r=0.32, P<0.0001) at baseline for matched segments. A similar pattern of correlations was observed for global (all segments) QCA-derived and single-vessel IVUS-derived data. There were statistically significant but weak correlations between the changes over time in lumen dimensions on QCA and IVUS (P=0.005) and between the change in cumulative coronary stenosis score on QCA and percent atheroma volume on IVUS (r=0.14, P=0.01). Nevertheless, patients with and without angiographic progression had changes in plaque volume on IVUS of 9.13 and 0.20 mm3, respectively (P=0.028).

CONCLUSIONS

QCA- and IVUS-derived measures of lumen dimensions are correlated at single time points and for changes over time. Although the change in percent atheroma volume is only weakly correlated with QCA changes as continuous variables, disease progression on QCA is associated with significant increases in plaque volume on IVUS compared with no angiographic progression.

Accurate quantification of dimethylamine (DMA) in human urine by gas chromatography-mass spectrometry as pentafluorobenzamide derivative: evaluation of the relationship between DMA and its precursor asymmetric dimethylarginine (ADMA) in health and disease

Dimethylamine [DMA, (CH(3))(2)NH)] is abundantly present in human urine. Main sources of urinary DMA have been reported to include trimethylamine N-oxide, a common food component, and asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide (NO) synthesis. ADMA is excreted in the urine in part unmetabolized and in part after hydrolysis to DMA by dimethylarginine dimethylaminohydrolase (DDAH). Here we describe a GC-MS method for the accurate and rapid quantification of DMA in human urine. The method involves use of (CD(3))(2)NH as internal standard, simultaneous derivatization with pentafluorobenzoyl chloride and extraction in toluene, and selected-ion monitoring of m/z 239 for DMA and m/z 245 for (CD(3))(2)NH in the electron ionization mode. GC-MS analysis of urine samples from 10 healthy volunteers revealed a DMA concentration of 264+/-173 microM equivalent to 10.1+/-1.64 micromol/mmol creatinine. GC-tandem MS analysis of the same urine samples revealed an ADMA concentration of 27.3+/-15.3 microM corresponding to 1.35+/-1.2 micromol/mmol creatinine. In these volunteers, a positive correlation (R=0.83919, P=0.0024) was found between urinary DMA and ADMA, with the DMA/ADMA molar ratio being 10.8+/-6.2. Elevated excretion rates of DMA (52.9+/-18.5 micromol/mmol creatinine) and ADMA (3.85+/-1.65 micromol/mmol creatinine) were found by the method in 49 patients suffering from coronary artery disease, with the DMA/ADMA molar ratio also being elevated (16.8+/-12.8). In 12 patients suffering from end-stage liver disease, excretion rates of DMA (47.8+/-19.7 micromol/mmol creatinine) and ADMA (5.6+/-1.5 micromol/mmol creatinine) were found to be elevated, with the DMA/ADMA molar ratio (9.17+/-4.2) being insignificantly lower (P=0.46). Between urinary DMA and ADMA there was a positive correlation (R=0.6655, P<0.0001) in coronary artery disease, but no correlation (R=0.27339) was found in end-stage liver disease.

Relation between atherosclerosis risk factors and aspirin resistance in a primary prevention population

Resistance to inhibition of platelet function by aspirin may contribute to future myocardial infarction and stroke. Adverse cardiovascular outcomes have been associated with aspirin resistance on several different platelet function assays, including the level of urinary 11-dehydro thromboxane B2 (Tx-M), platelet aggregation to arachidonic acid and adenosine diphosphate, and closure time on the platelet function analyzer-100. We examined the concordance of these aspirin-resistance assays and their relation to cardiovascular risk factors in a primary prevention population. Asymptomatic patients (n = 1,311) at increased risk for coronary heart disease were evaluated before and after 2 weeks of aspirin (81 mg/day). Aspirin resistance was defined according to published criteria for these 3 assays of platelet function. Subjects were characterized for the presence of atherosclerosis risk factors. Agreement among the 3 assays was poor. Only 5 patients met aggregation criteria for aspirin resistance. Attenuated suppression of urinary Tx-M by aspirin was associated with a greater atherosclerotic risk profile and Framingham risk score in multivariable regression analysis. Aspirin resistance by platelet function analyzer-100 was associated only with increased von Willebrand factor levels and not with atherosclerotic risk profile. In conclusion, in a primary prevention population, different published criteria for aspirin resistance classify distinct groups of patients as aspirin resistant with very little overlap. Higher Tx-M, which reflects decreased suppression of thromboxane production in vivo, is the only criterion associated with atherosclerosis risk factors, suggesting that this measurement may represent the most relevant approach for identifying asymptomatic subjects whose aspirin treatment will "fail."

Urinary levels of matrix metalloproteinase 9 and 2 and tissue inhibitor of matrix metalloproteinase in patients with coronary artery disease

OBJECTIVES

To evaluate the feasibility of an assay for urinary levels of matrix metalloproteinases (MMPs) and the potential usefulness of urinary MMPs as a marker of coronary atherosclerosis or acute coronary syndromes (ACS).

METHODS AND RESULTS

We measured urine and plasma MMP-9, MMP-2 and urine tissue inhibitor of metalloproteinase (TIMP-1) in patients with ACS (n=27), patients with coronary artery disease (CAD), but no clinical instability (n=47) and a group of healthy volunteers (n=15) who were <35 years of age, had no risk factors for CAD and did not undergo angiography. Compared with volunteers, patients with ACS and CAD had higher urine MMP-9, urine TIMP-1, plasma MMP-9 and plasma MMP-2 levels, but these did not differ between those with CAD and ACS. Using the volunteers to roughly establish an upper limit of normal, 84% of the urine TIMP-1 values and 95% of the urine MMP-9 values were abnormally elevated among those with CAD and ACS.

CONCLUSIONS

Urine MMP-9 and TIMP-1 levels are elevated in patients with CAD and ACS compared with healthy volunteers. A high percent of patients with CAD or ACS had elevated urine values of MMP-9 and TIMP-1 suggesting these variables might be a useful marker of atherosclerotic disease.

Reduced Blood Platelet Sensitivity to Aspirin in Coronary Artery Disease: Are Dyslipidaemia and Inflammatory States Possible Factors Predisposing to Sub-optimal Platelet Response to Aspirin?

The study was designed to assess blood platelet sensitivity to acetylsalicylic acid and its associations with dyslipidaemia and inflammation in coronary artery disease patients. Platelet non-responsiveness to aspirin is associated with an increased risk of serious cardiovascular events. Several environmental and hereditary factors are reportedly involved in sub-optimal acetylsalicylic acid response. Forty-five coronary artery disease patients and 45 non-coronary artery disease controls received acetylsalicylic acid at a daily dose of 75-150 mg. Controls were examined twice: on the day of entering the study and 10 days later. Urinary 11-dehydrothromboxane B2 was assessed as the marker of platelet thromboxane generation. Aggregation was studied in platelet-rich plasma using turbidimetric aggregometry with collagen and arachidonic acid. Fifty to seventy percent of coronary artery disease patients showed an extent of collagen-induced aggregation above the upper quartile of the reference range compared with 8-15% in controls (P<0.003). For arachidonic acid-activated aggregation these proportions were 45-50% in coronary artery disease versus 7% in controls (P<0.007). In coronary artery disease patients, the acetylsalicylic acid-mediated platelet inhibition positively correlated with increased triglycerides (in arachidonic acid-stimulated platelets, r=0.30, P=0.0018), total cholesterol (r=0.33, P<0.0001 in coll and arachidonic acid-activated platelets) and elevated serum C-reactive protein (CRP) (r=0.27, P=0.0024). In coronary artery disease patients urine 11-dehydrothromboxane B2 concentrations were significantly increased compared to controls after 10 day acetylsalicylic acid intake (563; 313-728 pg/mg creatinine versus 321; 246-488 pg/mg creatinine, P=0.04). The incidence of suboptimal acetylsalicylic acid response incidence was more common in patients with coronary artery disease. Acetylsalicylic acid inhibition of blood platelet reactivity and thromboxane generation was less effective in these patients. Dyslipidaemia and chronic inflammatory states may promote suboptimal acetylsalicylic acid response in coronary artery disease patients.

[Urinary albumin excretion and coronary artery disease]

The moderate elevation in urinary albumin excretion defined as microalbuminuria is common in the population and associated with cardiovascular (CV) risk factors. Microalbuminuria prevalence is low in the absence of CV risk factors and progressively increases with the number of the individual's CV risk factors. The main correlate of microalbuminuria is blood pressure (BP). The relationship between BP and microalbuminuria is continuous and graded since the prevalence of microalbuminuria increases with the severity of hypertension. Among hypertensives receiving treatment, BP control is associated with a low prevalence of microalbuminuria. Therefore, BP appears as a determinant of microalbuminuria rather than a mere correlate. For hypercholesterolemia, smoking and diabetes, the data are less strong, but point to an independent positive association with microalbuminuria. Altogether, data indicate that microalbuminuria in the population reflects the presence of CV risk factors. Data concerning microalbuminuria and coronary heart disease (CHD) support this idea. There is a continuous and graded relationship between urinary albumin excretion and CHD prevalence. High urinary albumin excretion is a likely sign of vascular damage existing both at renal and cardiac levels and induced by one or more uncontrolled CV risk factors.

Homocysteine concentrations in type 2 diabetic patients with silent myocardial ischemia: a predictive marker

BACKGROUND

Silent myocardial ischemia (SMI) is a frequent finding among diabetic patients. There are very few data on the relationship between homocysteine, which is a novel cardiovascular risk factor, and SMI in diabetic patients. We investigated whether plasma homocysteine has a predictive value for early diagnosis of SMI in type 2 diabetic patients.

METHODS

One hundred and twenty diabetic patients and 25 control subjects were evaluated. Among diabetic patients, 29 had a history or clinical signs of coronary artery disease (CAD). All other patients who had normal ECGs and no history or clinical signs of CAD were screened by exercise test. Thirty-eight patients with maximal negative exercise test were labelled as CAD (-) diabetic patient group. Angiography was performed on patients who had positive exercise tests and among them 23 patients had angiographically documented SMI.

RESULTS

CAD (+) and SMI groups had significantly higher serum homocysteine concentrations than CAD (-) and control groups (14.2+/-6.6, 15.7+/-7.8, 9.6+/-3.23, 9.3+/-2.25 micromol/l, respectively). In the SMI (+) diabetic group there was a significant correlation between serum homocysteine concentrations and creatinine, microalbuminuria and folic acid levels. Multiple regression analysis showed that homocysteine concentration was dependent on microalbuminuria, folic acid levels and presence or absence of ischemia.

CONCLUSION

The present investigation shows an association of homocysteine with SMI in diabetic patients. Other prospective studies are needed to establish whether homocysteine levels can be used as a suitable marker for CAD screening in type 2 diabetic patients.

Association of microalbuminuria with carotid intima-media thickness and coronary artery disease--a cross-sectional study in Western India

OBJECTIVE

Microalbuminuria, a slightly elevated albumin excretion in the urine, is considered a novel atherosclerotic risk factor, both in diabetics subjects and in general population. Carotid intima-media thickness assessed non-invasively by a B-mode ultrasound has been recently shown to be an early marker for atherosclerosis. This study aims at determining the role of microalbuminuria as an atherosclerotic risk factor and its association with coronary artery disease.

METHODS

We measured the urine microalbumin excretion and carotid intima-media thickness (IMT) in 301 subjects, with or without evidence for coronary artery disease (CAD). Microalbuminuria was diagnosed if urinary excretion of albumin exceeded 20 microgm/ml.

RESULTS

Of the 301 subjects (age group--30-80 years) recruited for the study, 194 were males, 107 females. One hundred amd eighteen subjects had evidence of CAD as diagnosed by documented hospitalization with myocardial infarction or acute coronary syndrome, coronary angiography when feasible or non-invasive cardiac evaluation. One hundred and sixty three subjects had diabetes mellitus. Microalbuminuria was detected in 74 subjects (24.6%). Prevalence of subjects with increased IMT was higher among subjects with microalbuminuria compared to normoalbuminuria (42% vs 21.4%, p < 0.003). Prevalence of CAD was significantly higher among diabetic subjects with microalbuminuria compared to those with normoalbuminuria (Diabetic subjects: 58% vs 31.9%, p = 0.002, Non-diabetic subjects: 41.7% vs 37.7%, p = 0.718). Multivariate logistic regression analysis using carotid intimal medial thickness as a dependent variable revealed a statistically significant association with microalbuminuria in diabetic subjects (p = 0.027).

CONCLUSION

We conclude that microalbuminuria shows a strong association with increased carotid intimal medial thickening and coronary artery disease in diabetic subjects in this Western Indian population.

Renal dose dopamine in open heart surgery. Does it protect renal tubular function?

BACKGROUND

This prospective, randomized study assessed the effect of dopamine on renal tubular function in patients who had coronary artery bypass grafting.

METHODS

Two groups of patients with normal preoperative renal function were randomly divided into a dopamine group (n=11), who received dopamine in a dose of 2 mg/kg x min, and a control group (n=11), who received no treatment. Dopamine infusion was initiated 24 hours before the operation and was continued for 48 hours postoperatively. Measurements of renal function obtained 2 days before the operation were considered preoperative and were repeated on the 1st, 3rd, and 7th postoperative days. Urinary excretion of b2-Microglobulin (b2-M), considered a sensitive means for diagnosing proximal tubular damage, was measured during the early (day 3) and late (day 7) postoperative period.

RESULTS

There were no significant differences respect to the clearances of creatinine, osmotic, and free-water in the dopamine group compared with the control group (p>0.05). Urine microalbumin levels significantly increased on postoperative day 3 in both groups. During the early postoperative period, excretion of urine b2-M was significantly greater in the dopamine group than in the control group (p<0.05).

CONCLUSIONS

Consequently, in patients with normal preoperative renal and cardiac function scheduled for elective coronary artery bypass grafting, renal dose dopamine infusion alone may not provide sufficient protection on tubular function and increases renal tubular injury during the early postoperative period.

Proteinuria is a key determinant of death in patients with diabetes after isolated coronary artery bypass grafting

BACKGROUND

Proteinuria is a marker for underlying diabetic nephropathy and may be a surrogate marker for advanced atherosclerosis. It is unknown if proteinuria is a determinant of death in patients with diabetes after coronary artery bypass grafting. We hypothesized that diabetic patients with evidence of proteinuria would have increased mortality and clinical event rates after isolated coronary artery bypass grafting compared with nonproteinuric diabetic patients.

METHODS AND RESULTS

We performed an observational of study of 905 diabetic patients with urinalysis and available follow-up data (nonproteinuria, n = 651; proteinuria, n = 254) after isolated coronary artery bypass grafting at the Cleveland Clinic Foundation between January 1989 and December 1992. The proteinuria group was further prospectively stratified into low-concentration (n = 225) and high-concentration (n = 29) groups. The end points of this study were all-cause mortality and the composite end point of death, nonfatal myocardial infarction, and need for repeat revascularization. The mean follow-up time was 66 months. The 5-year mortality rate for the nonproteinuria and proteinuria groups was 20.2% and 29.1% (P <.001), respectively. The 5-year rate of death, nonfatal myocardial infarction, and need for repeat revascularization for the nonproteinuria and proteinuria groups was 25.2% and 36.2% (P <.001), respectively. Significant multivariate predictors of 5-year mortality included age, not using a left internal mammary artery graft to the left anterior descending coronary artery, proteinuria, lower body weight, and increased creatinine level.

CONCLUSIONS

Among diabetic patients, proteinuria appears to be an important predictor of death after isolated coronary artery bypass grafting.

Microalbuminaria and the risk of atherosclerosis. Clinical epidemiological and physiological investigations

Microalbuminuria, i.e., slightly elevated albumin excretion in the urine, is considered a novel atheroslerotic risk factor. This supposition is based partly on two preliminary minor studies, partly on the current knowledge within the fields of diabetes mellitus and arterial hypertension. The aims of the present series of studies were 1) to examine whether a relationship exists between microalbuminuria and atherosclerotic cardiovascular disease in the general population, and 2) to illuminate possible pathophysiological mechanisms underlying this association. The studies were performed as sub-studies of the Copenhagen City Heart Study and the Monica Population Study. In the 3rd Copenhagen City Heart Study a cross-sectional analysis comprising 2,613 individuals without diabetes mellitus or renal- or urinary tract disease revealed a positive association between overnight urinary albumin excretion rate and a history of acute myocardial infarction. This association was independent of age, sex, conventional atherosclerotic risk factors, and glomerular filtration rate. Participants with a urinary albumin excretion rate exceeding the upper decile (7 micrograms/min) in the entire study population had a higher frequency of previous acute myocardial infarction than the others. In order to assess the time sequence of the observed association, this population will be followed prospectively. In the 1st Monica Population Study in Copenhagen County, 2,085 individuals without diabetes, mellitus, cardiovascular disease, or renal or urinary tract disease were followed for 10 years. Participants with a urinary albumin/creatinine concentration ratio exceeding the upper decile (0.65, mg/mmol) in the entire study population had a relative risk of 2.3 for developing ischaemic heart disease as compared to participants with a lower urinary albumin/creatinine concentration ratio. This predictive effect was independent of age, sex, and conventional atherosclerotic risk, factors, but it was not known whether participants with a urinary albumin/creatinine concentration ratio above the upper decile had severe subclinical atherosclerosis already at entrance to the study. A group of individuals with persistent microalbuminuria, and an age- and sex-matched control group with persistent normoalbuminuria underwent a clinical physiological and biochemical investigation program. None had developed clinically present atherosclerotic cardiovascular disease. Microalbuminuria was defined as a urinary albumin excretion rate exceeding the upper decile in the entire study population, normoalbuminuria as a lower urinary albumin excretion rate. Measurements of glomerular filtration rate and tubular function made it unlikely that the difference in urinary albumin excretion between the two study groups was due to local renal conditions exclusively, although reductions in both glomerular charge selectivity and size selectivity were observed in the microalbuminuric individuals. Individuals with persistent microalbuminuria had increased systemic transvascular albumin leakage to a level similar to that seen among individuals with severe clinical atherosclerosis. This could be explained neither by differences in blood pressure or concentration of plasma lipoproteins, both of which were more atherogenic in the microalbuminuric individuals, nor by differences in plasma volume or albumin concentration, antropometric factors, insulin sensitivity, or smoking habits. It is hypothesized that the systemic transvascular leakiness may also include lipoproteins, thus allowing for an increased lipid insudation into the vessel walls. The leakiness might be due to haemodynamic factors or structural or functional perturbations of the endothelium or the intracellular matrix beneath. Although endothelial dysfunction could not be demonstrated in the present studies, future research will focus on these possibilities.

The importance of proteinuria as a determinant of mortality following percutaneous coronary revascularization in diabetics

OBJECTIVES

The aims of this study were to compare mortality and clinical events following percutaneous coronary intervention (PCI) between nondiabetics and diabetics with and without proteinuria.

BACKGROUND

Diabetics have increased rates of late myocardial infarction, repeat revascularization and mortality when compared with nondiabetics following PCI. Proteinuria is a marker for diabetic nephropathy and potentially a surrogate marker for advanced atherosclerosis. It is unknown if proteinuria is a predictor of outcome in diabetics following PCI.

METHODS

We performed an observational study of 2,784 patients who underwent PCI at the Cleveland Clinic between January 1993 and December 1995. There were 2,247 nondiabetics and 537 diabetics with urinalysis and follow-up data available (proteinuria n = 217, nonproteinuria n = 320). The diabetic proteinuria group was further prospectively stratified into low concentration (n = 182) and high concentration (n = 35). The end points were all-cause mortality and the composite end point of death, nonfatal myocardial infarction (MI) and need for revascularization.

RESULTS

The mean follow-up time was 20.2 months. The two-year mortality rate was 7.3% and 13.5% for nondiabetics and diabetics, respectively (p < 0.001). The two-year mortality rate was 9.1% and 20.3% for the nonproteinuria and proteinuria groups, respectively (p < 0.001). There was a graded increase in mortality comparing the diabetic group. The two-year mortality rate was 9.1%, 16.2% and 43.1% for the nonproteinuria, low concentration and high concentration groups, respectively (p < 0.001). The difference in survival between the nondiabetic and nonproteinuric diabetics was not significant (p = 0.8).

CONCLUSIONS

The presence of proteinuria is the key determinant of risk following PCI for diabetics. Diabetics without evidence of proteinuria have similar survival compared with nondiabetics.

Urinary albumin excretion in hospitalized patients with acute myocardial infarction. Prevalence of microalbuminuria and correlation to left ventricle wall thickness

Microalbuminuria, a subclinical rise in the urinary albumin excretion, is a risk indicator of atherosclerotic cardiovascular disease. The aim of this study was to measure the urinary albumin excretion in patients with acute myocardial infarction, and to correlate this with known atherosclerotic risk factors. One-hundred-and-twenty-six patients and 56 healthy controls matched for age and sex were studied. The albumin/creatinine concentration ratio in morning urine specimens was calculated as an index of the albumin excretion. Microalbuminuria was defined as a urinary albumin/creatinine concentration ratio above 1 mg/mmol. Urinary albumin excretion (0.88 [95% confidence interval 0.69-1.11] versus 0.51 [0.40-0.63] mg/mmol; p = 0.001) and frequency of microalbuminuria (33 [95% confidence interval 25-41] versus 16 [9-23]%; p = 0.03) were higher in patients than controls. This difference was independent of blood pressure, body weight, smoking, diabetes mellitus, renal disease, and thrombolytic treatment. There was a positive correlation between urinary albumin excretion and thickness of the left ventricle wall (R = 0.28; p = 0.001) which was independent of blood pressure. Follow-up examination of the patients will reveal whether microalbuminuria increases the risk for recurrence of acute myocardial infarction.

[Genetic dimorphism in beta-aminoisobutyric acid excretion in patients with atherosclerosis of the coronary artery and in groups at risk for atherosclerosis in the Lithuanian population]

Frequency of genetic variants of excretion of beta-aminoisobutyric acid (BAIB) in the urea was examined in patients suffering from atherosclerosis of coronary arteries and in risk group for atherosclerosis: children frequently suffering from respiratory viral infection, children with insulin-dependent diabetes mellitus (IDDM) and in adults suffering from IDDM and non-insulin-dependent diabetes mellitus. With the aim to determine whether excretion of BAIB could be related with CMV persistence of with proteolytic activity of blood serum the IgG class antibodies against CMV and level of alpha 1-proteinase inhibitor (alpha 1-PI) in blood serum was tested also. Frequency of high excretors of BAIB was found significantly more often (P < 0.01) in children suffering from virus infection compared to that of population. Frequency distribution of BAIB excretion showed that "high excretors" were found significantly more often in children suffering from atherosclerosis. The difference of BAIB excretion among healthy and diabetics was not defined (P > 0.05). The changes of excretion of BAIB in urea were not related with quantity of alpha 1-PI in blood serum. Investigation reveal a possible relation between high BAIB excretor and latent CMV infection and that this may impact atherogenesis. This leads to a suggestion that children who are often ill with respiratory virus infection may constitute a risk group for coronary atherosclerosis.