Urinary excretion of alpha1-microglobulin and albumin in acute myocardial infarction. Correlation with plasma concentrations of troponin I and C-reactive protein

Urinary Alpha1-Microglobulin: A New Predictor for In-Hospital Mortality in Patients with ST-Segment Elevation Myocardial Infarction

BACKGROUND Alpha1-microglobulin (A1MG) is a small molecular protein related to oxidation and inflammation. It exists in diverse body fluids, including urine. Results from urine tests are sometimes neglected when predicting in-hospital prognosis. It remains unclear whether urinary A1MG (UA1MG) can predict short-term prognosis of ST-elevated myocardial infarction (STEMI). MATERIAL AND METHODS A total of 1854 hospitalized patients with acute STEMI were retrospectively enrolled in our study. Medical records were used to obtain patient demographic and clinical information, UA1MG values (which were used to divide patients into groups of low, medium, or high), and other laboratory parameters. Principal clinical outcomes of interest were all-cause in-hospital deaths, cardiac deaths, and major adverse cardiac events (MACEs). RESULTS Among the 1854 enrolled patients, 43 (2.3%) died in the hospital, of which 33 (1.8%) were cardiac deaths. MACEs were noted in 113 patients (6.1%) during hospitalization. The group with the highest UA1MG value showed a significantly higher frequency of in-hospital deaths, cardiac deaths, and MACEs, compared to those of the lowest UA1MG value group (4.4% vs. 1.0%, P<0.001; 3.1% vs. 0.6%, P<0.005; and 8.6% vs. 4.7%, P=0.007, respectively). Multivariate regression analysis revealed that UA1MG levels (odds ratio 1.109, 95% confidence interval (CI) 1.027-1.197, P=0.008) independently predicted all-cause in-hospital mortality. A UA1MG value of 3.23 mg/dL was considered as an optimal cutoff point in STEMI to predict all-cause mortality after receiver operating characteristic curve analysis (area under the curve 0.73, 95% CI 0.65-0.80, P<0.001). CONCLUSIONS The UA1MG value at hospital admission could be an independent prognostic factor of all-cause in-hospital mortality in patients with STEMI.

Emerging families of biomarkers for coronary artery disease: inflammatory mediators

Introduction

Inflammation has been implicated in the development of atherosclerosis in patients with acute coronary syndrome. C-reactive protein is an established nonspecific prognostic inflammatory biomarker for patients with acute coronary syndrome in the medical literature. This has led to a concerted effort to identify circulating inflammatory biomarkers to facilitate predicting the risk for and diagnosing coronary artery disease in at-risk subjects. The objective of this study was to search after novel inflammatory biomarkers reported as useful for diagnosing coronary artery disease.

Methods

The PubMed database was searched for reports published from January 1, 2000 to June 30, 2012 of novel circulating biomarkers for coronary artery disease in addition to the established biomarker, C-reactive protein. The search terms used were “infarction”, “biomarkers”, and “markers”, and only original articles describing clinical trials that were written in English were included. All published articles were separately examined carefully after novel inflammatory markers for acute coronary syndrome. All irrelevant publications without content pertaining to inflammatory biomarkers for acute coronary syndrome were excluded from this study. Our results reflect all articles concerning biomarkers in humans.

Results

The PubMed search yielded 4,415 research articles. After further analysis, all relevant published original articles examining 53 biomarkers were included in this review, which identified 46 inflammation biomarkers useful for detecting coronary artery disease.

Conclusion

The emergence of diverse novel biomarkers for coronary artery disease has provided insight into the varied pathophysiology of this disease. Inflammatory biomarkers have tremendous potential in aiding the prediction of acute coronary syndrome and recurrent ischemic episodes, and will eventually help improve patient care and management.

The Relationship of Acute Myocardial Infarction With or Without ST-Segment Elevation and Viscosity

We compared hemorheological parameters in 42 male patients with acute myocardial infarction (AMI), with (n = 22) or without (n = 20) ST-segment elevation and in 20 controls. Plasma and blood viscosity (cP), plasma protein (g/dL) and fibrinogen (mg/dL) concentrations, red (106/µL) and white (103/µL) blood cell counts, hemoglobin concentration (g/dL), and hematocrit (%) were compared. Plasma viscosity was significantly higher in patients with AMI with ( P = .012) and without ( P = .046) ST-segment elevation than in controls. Patients with AMI with and without ST-segment elevation had significantly lower albumin ( P = .002 and P = .009) and globulin ( P = .001 and P = .007) concentrations, red blood cell counts ( P = .0001 and P = .004), and hematocrit ( P = .014 and P = .040) and significantly higher fibrinogen concentrations ( P = .0001 and P = .001) than controls. These findings suggest that AMI in males is associated with increased plasma viscosity and fibrinogen concentrations and with decreased albumin and globulin concentrations, erythrocyte count, and hematocrit, regardless of ST-segment elevation.

Comparison of C-reactive protein and albumin excretion as prognostic markers for 10-year mortality after myocardial infarction

BACKGROUND

C-reactive protein (CRP) is an established prognostic marker in the setting of acute coronary syndromes. Recently, albumin excretion rate also has been found to be associated with adverse outcomes in this clinical setting. Our aim was to compare the prognostic power of CRP and albumin excretion rate for long-term mortality following acute myocardial infarction (AMI).

HYPOTHESIS

To determine whether albumin excretion rate is a better predictor of long-term outcome than CRP in post-AMI patients.

METHODS

We prospectively studied 220 unselected patients with definite AMI (median [interquartile] age 67 [60-74] y, female 26%, heart failure 39%). CRP and albumin-to-creatinine ratio (ACR) were measured on day 1, day 3, and day 7 after admission in 24-hour urine samples. Follow-up duration was 10 years for all patients.

RESULTS

At survival analysis, both CRP and ACR were associated with increased risk of 10-year all-cause mortality, also after adjusting for age, hypertension, diabetes mellitus, prehospital time delay, creatine kinase-MB isoenzyme peak, heart failure, and creatinine clearance. CRP and ACR were associated with nonsudden cardiovascular (non-SCV) mortality but not with sudden death (SD) or noncardiovascular (non-CV) death. CRP was not associated with long-term mortality, while ACR was independently associated with outcome both in short- and long-term analyses. At C-statistic analysis, CRP did not improve the baseline prediction model for all-cause mortality, while it did for short-term non-SCV mortality. ACR improved all-cause and non-SCV mortality prediction, both in the short and long term.

CONCLUSIONS

ACR was a better predictor of long-term mortality after AMI than CRP.