Diagnostic and prognostic value of uric acid in patients with acute dyspnea

Automatically computed ECG algorithm for the quantification of myocardial scar and the prediction of mortality

BACKGROUND

Myocardial scar is associated with adverse cardiac outcomes. The Selvester QRS-score was developed to estimate myocardial scar from the 12-lead ECG, but its manual calculation is difficult. An automatically computed QRS-score would allow identification of patients with myocardial scar and an increased risk of mortality.

OBJECTIVES

To assess the diagnostic and prognostic value of the automatically computed QRS-score.

METHODS

The diagnostic value of the QRS-score computed automatically from a standard digital 12-lead was prospectively assessed in 2742 patients with suspected myocardial ischemia referred for myocardial perfusion imaging (MPI). The prognostic value of the QRS-score was then prospectively tested in 1151 consecutive patients presenting to the emergency department (ED) with suspected acute heart failure (AHF).

RESULTS

Overall, the QRS-score was significantly higher in patients with more extensive myocardial scar: the median QRS-score was 3 (IQR 2-5), 4 (IQR 2-6), and 7 (IQR 4-10) for patients with 0, 5-20 and > 20% myocardial scar as quantified by MPI (p < 0.001 for all pairwise comparisons). A QRS-score ≥ 9 (n = 284, 10%) predicted a large scar defined as > 20% of the LV with a specificity of 91% (95% CI 90-92%). Regarding clinical outcomes in patients presenting to the ED with symptoms suggestive of AHF, mortality after 1 year was 28% in patients with a QRS-score ≥ 3 as opposed to 20% in patients with a QRS-score < 3 (p = 0.001).

CONCLUSIONS

The QRS-score can be computed automatically from the 12-lead ECG for simple, non-invasive and inexpensive detection and quantification of myocardial scar and for the prediction of mortality. TRIAL-REGISTRATION: http://www.clinicaltrials.gov . Identifier, NCT01838148 and NCT01831115.

Determinants and Prognostic Impact of Hyperuricemia in Hospitalization for Acute Heart Failure

BACKGROUND

Hyperuricemia is a prognostic factor in patients with chronic heart failure, but whether uric acid level can predict clinical outcome of acute heart failure (AHF) remains to be elucidated. We therefore investigated the association of uric acid with mortality in patients hospitalized for AHF.

METHODS AND RESULTS

Data for patients hospitalized for AHF were drawn from an intramural registry. Biochemistry data, echocardiographic characteristics, and uric acid level were collected. National Death Registry was linked for the identification of mortality data. Among a total of 1,835 participants (age, 75 ± 13 years, 68% men), 794 patients died during follow-up. Patients who died were older, had lower hemoglobin and estimated glomerular filtration rate, and higher pulmonary artery systolic pressure, NT-proBNP, and uric acid. Uric acid was a significant predictor of mortality on univariate analysis (HR per 1 SD, 1.18; 95% CI: 1.11-1.26) and in multivariate Cox models (HR, 1.15; 95% CI: 1.02-1.29). Survival analysis showed an increasing risk of death along the quartile distribution of uric acid level. Given renal function, cardiac performance, and kidney perfusion as major determinants of hyperuricemia, the prognostic impact of uric acid level was diminished as renal function deteriorated.

CONCLUSIONS

Uric acid level was an independent predictor of mortality in patients hospitalized for AHF, but the prognostic impact of hyperuricemia was attenuated by worsening renal function.

Post-ICU discharge and outcome: rationale and methods of the The French and euRopean Outcome reGistry in Intensive Care Units (FROG-ICU) observational study

BACKGROUND

Previous studies have demonstrated that ICU (intensive care unit) survivors have decreased long-term survival rates compared to the general population. However, knowledge about how to identify ICU survivors with higher risk of death and the adjustable factors associated with mortality is still lacking.

METHODS AND DESIGN

The FROG-ICU (the French and European Outcome Registry in Intensive Care Units) study is a prospective, observational, multicenter cohort study where ICU survivors are followed up to one year after ICU discharge. Beside one year survival, the study is designed to assess incidence and identifying risk factors for mortality over the year following discharge from the ICU. All consecutive patients admitted in ICU to the 28 participating centers during the study period will be included. Every subject will undergo an evaluation at admission, throughout the ICU stay and at ICU discharge. The global, especially cardiovascular, assessment of each subject will be performed through a complete clinical exam, instrumental tests (electrocardiogram, echocardiogram) and biological parameters. Blood and urine samples will be collected at admission and at discharge with the primary goal to assess effectiveness of routine and novel cardiovascular, inflammatory and renal biomarkers, with potential interest in risk stratification for patients who survive an ICU stay. The follow up will include a careful tracking of patients through telephone calls and questionnaires at 3, 6 and 12 months after ICU discharge. FROG-ICU aims to identify the clinical and biological phenotype of patients with different levels of probability of death in the year after ICU discharge.

DISCUSSION

FROG-ICU has been designed to better understand long term outcome after ICU discharge as well as risk factors for all-cause and cardiovascular morbidity and associated mortality. It is a large prospective multicenter cohort with a biological (on plasma and urine) collection and one-year follow-up of ICU patients. FROG ICU will allow performing a risk stratification of ICU survivors as to recognize the subset of patients who may benefit from an early intervention to allow decreased cardiovascular morbidity and related mortality.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01367093 .

Uric acid in heart failure: a biomarker or therapeutic target?

There is a need for a cost-effective prognostic biomarker in heart failure (HF). Substantial evidence suggests that uric acid (UA) is an independent marker for adverse prognosis in acute and chronic HF of varying severity. Whether UA is a merely a marker of poor prognosis or is an active participant in disease pathogenesis is currently unknown. In the setting of HF, at least two different processes can be responsible for increased UA: increased production, which may result from oxidative stress, and decreased excretion due to renal insufficiency, which can be a consequence of cardio-renal syndrome, renal congestion, or comorbidities. While pioneer studies have raised the possibility of preventing HF through the use of UA lowering agents, namely xanthine oxidase inhibitors and uricosurics, the literature is still conflicting on whether the reduction in UA will result in a measurable clinical benefit. In this review, we examine the evidence relating UA to HF prognosis, the mechanisms that contribute to increased UA levels in HF, and future novel treatments aimed at reducing UA levels.

Uric acid for diagnosis and risk stratification in suspected myocardial infarction

BACKGROUND

Hypoxia precedes cardiomyocyte necrosis in acute myocardial infarction (AMI). We therefore hypothesized that uric acid - as a marker of oxidative stress and hypoxia - might be useful in the early diagnosis and risk stratification of patients with suspected AMI.

MATERIALS AND METHODS

In this prospective observational study, uric acid was measured at presentation in 892 consecutive patients presenting to the emergency department with suspected AMI. The final diagnosis was adjudicated by two independent cardiologists. Patients were followed 24 months regarding mortality. Primary outcome was the diagnosis of AMI, secondary outcome was short- and long-term mortality.

RESULTS

Uric acid at presentation was higher in patients with AMI than in patients without (372 μM vs. 336 μM; P < 0·001). The diagnostic accuracy of uric acid for AMI as quantified by the area under the receiver operating characteristic curve (AUC) was 0·60 (95%Cl 0·56-0·65). When added to cardiac troponin T (cTnT), uric acid significantly increased the AUC of cTnT from 0·89 (95%Cl 0·85-0·93) to 0·92 (95%Cl 0·89-0·95, P = 0·020 for comparison). Cumulative 24-month mortality rates were 2·2% in the first, 5·4% in the second and the third and 15·6% in the fourth quartile of uric acid (P < 0·001 for log-rank). Uric acid predicted 24-month mortality independently. Adding uric acid to TIMI and GRACE risk score improved their prognostic accuracy as shown by an integrated discrimination improvement of 0·04 (P = 0·007) respective 0·02 (P = 0·021).

CONCLUSIONS

Uric acid, an inexpensive widely available biomarker, improves both the early diagnosis and risk stratification of patients with suspected AMI.

Potentials of cystatin C and uric acid for predicting prognosis of heart failure

Few studies have explored the clinical potentials of combined Cystatin C (Cys) and uric acid (UA) in heart failure (HF). The authors evaluated Cys and UA as predictors of clinical outcomes compared with conventional renal biomarkers. This prospective cohort study included 587 HF patients presenting with dyspnea. At admission, Cys, UA, and other renal measures including serum urea nitrogen (BUN), creatinine (Cr), and glomerular filtration rate (GFR) were obtained. The primary endpoint was the composite of cardiac death and rehospitalization for worsening HF. During a 25-month median follow-up period, 68 patients experienced clinical outcomes: 9 cardiac deaths and 59 HFs. They showed higher BUN and Cr values and lower GFR. Within these parameters, Cys and UA had the most favorable area under the curves, and patients with Cys ≥0.8 mg/L and UA ≥6.6 mg/dL showed more frequent events. The net reclassification improvement analysis showed the combination of Cys and UA had a greater incremental effect for cardiac prognosis. On multivariate Cox hazard analysis, Cys and UA were independent predictive markers for clinical outcomes. In HF patients presenting with dyspnea, Cys and UA appear to be more useful predictors of clinical events than other renal measures.

Serum uric acid levels correlate with filling pressures in systolic heart failure

The authors studied the relationship between liver function tests and serum uric acid level with clinical and hemodynamic profiles in heart failure. Fifty patients (aged 44±15 years; 74.5% men) with an ejection fraction (EF) <35% were enrolled and clinical assessment was performed. Hemodynamic indices (including pulmonary arterial pressure [PAP], pulmonary capillary wedge pressure [PCWP], and cardiac index were studied by standard Edwards Lifesciences Swan-Ganz catheters, and liver function tests and serum uric acid level were measured simultaneously. Fifty age- and sex-matched controls with normal EF were also studied. A total of 73% of patients had ischemic cardiomyopathy. Mean uric acid level was 7.2±3.8 mg/dL and was significantly higher than in the control group (P value<.001). In multivariate analysis, uric acid correlated significantly with PAP (r=.5, P<.001) and PCWP (r=.4, P=.002) and was also associated with clinical signs of rales, edema, paroxysmal nocturnal dyspnea (r=.5, P=.01), and New York Heart Association class (r=.4, P=.005). Uric acid level was also correlated inversely with left ventricular EF (r=.27, P=.006). Elevated uric acid levels in patients with systolic heart failure is associated with impaired clinical and hemodynamic profile and might be used as a noninvasive indicator of elevated left ventricular filling pressures.

Effect of oral β-blocker on short and long-term mortality in patients with acute respiratory failure: results from the BASEL-II-ICU study

INTRODUCTION

Acute respiratory failure (ARF) is responsible for about one-third of intensive care unit (ICU) admissions and is associated with adverse outcomes. Predictors of short- and long-term outcomes in unselected ICU-patients with ARF are ill-defined. The purpose of this analysis was to determine predictors of in-hospital and one-year mortality and assess the effects of oral beta-blockers in unselected ICU patients with ARF included in the BASEL-II-ICU study.

METHODS

The BASEL II-ICU study was a prospective, multicenter, randomized, single-blinded, controlled trial of 314 (mean age 70 (62 to 79) years) ICU patients with ARF evaluating impact of a B-type natriuretic peptide- (BNP) guided management strategy on short-term outcomes.

RESULTS

In-hospital mortality was 16% (51 patients) and one-year mortality 41% (128 patients). Multivariate analysis assessed that oral beta-blockers at admission were associated with a lower risk of both in-hospital (HR 0.33 (0.14 to 0.74) P = 0.007) and one-year mortality (HR 0.29 (0.16 to 0.51) P = 0.0003). Kaplan-Meier analysis confirmed the lower mortality in ARF patients when admitted with oral beta-blocker and further shows that the beneficial effect of oral beta-blockers at admission holds true in the two subgroups of patients with ARF related to cardiac or non-cardiac causes. Kaplan-Meier analysis also shows that administration of oral beta-blockers before hospital discharge gives striking additional beneficial effects on one-year mortality.

CONCLUSIONS

Established beta-blocker therapy appears to be associated with a reduced mortality in ICU patients with acute respiratory failure. Cessation of established therapy appears to be hazardous. Initiation of therapy prior to discharge appears to confer benefit. This finding was seen regardless of the cardiac or non-cardiac etiology of respiratory failure.

TRIAL REGISTRATION

clinicalTrials.gov Identifier: NCT00130559.

Use of myeloperoxidase for risk stratification in acute heart failure

BACKGROUND

Myeloperoxidase (MPO) is a biomarker of inflammation and oxidative stress produced by neutrophils, monocytes, and endothelial cells. Concentrations of MPO predict mortality in patients with chronic heart failure. This study sought to investigate the diagnostic accuracy and prognostic value of MPO in patients with acute heart failure (AHF).

METHODS

We prospectively enrolled 667 patients presenting to the emergency department with dyspnea and observed them for 1 year. MPO and B-type natriuretic peptide (BNP) were measured at presentation. Two independent cardiologists adjudicated final discharge diagnoses.

RESULTS

MPO concentrations were similar in patients with AHF (n = 377, median 139 pmol/L) and patients with noncardiac causes of dyspnea (n = 290, median 150 pmol/L, P = 0.26). The diagnostic accuracy of MPO for AHF was limited [area under the ROC curve (AUC) 0.53] and inferior to that of BNP (AUC 0.95, P < 0.001). In patients with AHF, MPO concentrations above the lowest tertile (MPO >99 pmol/L) were associated with significantly increased 1-year mortality (hazard ratio 1.58, P = 0.02). The combination of MPO (< or = 99 vs >99 pmol/L) and BNP (median of < or = 847 vs >847 ng/L) improved the prediction of 1-year mortality (hazard ratio 2.80 for both variables increased vs both low, P < 0.001). After adjustment for cardiovascular risk factors in multivariable Cox proportional hazard analysis, increases in MPO contributed significantly toward the prediction of 1-year mortality (hazard ratio 1.51, P = 0.045).

CONCLUSIONS

MPO is an independent predictor of 1-year mortality in AHF, is additive to BNP, and could be helpful in identifying patients with a favorable prognosis despite increased BNP concentrations.