Influence of left ventricular filling pattern on exercise-induced changes of natriuretic peptides in patients with suspected coronary artery disease

Stress-delta B-type Natriuretic Peptide Levels as a Test for Inducible Myocardial Ischemia: A Systematic Review and Meta-Analysis

Background Cardiac ischemia induces myocardial dysfunction and ventricular wall stretch, which causes the release of B-type natriuretic peptide (BNP) into the bloodstream. However, it is unclear whether inducible ischemia produces a significant change in BNP levels ("stress delta-BNP"). The objective of this study was to determine the utility of stress-delta BNP levels and its precursor NT-proBNP for detecting inducible myocardial ischemia during cardiac stress testing. Methods We conducted a systematic review and meta-analysis. We searched PubMed, EMBASE, Web of Science, Cumulative Index of Nursing and Allied Health Literature (CINAHL), and Ovid. Studies examining the changes in levels of BNP and its precursor, N-terminal pro-B-type natriuretic peptide (NT-proBNP), after an exercise cardiac stress test were included. Two reviewers independently analyzed titles and abstracts. Abstracts that did not provide enough information regarding eligibility criteria were kept for full-text evaluation. The same two reviewers also performed data extraction for analyses. Any disagreement was resolved by a consensus and, if it persisted, by a third reviewer adjudication. We report the median and mean values in studies in the order of sample size. Results A total of 15 studies met the inclusion criteria. Nine studies reported results in medians and six studies reported results in means. Of the nine studies, five assessed BNP alone, three assessed NT-proBNP, and one assessed both. Due to the non-normal distribution of results in these studies, they could not be meta-analyzed. Of the six studies that reported results in means, three assessed BNP and three assessed NT-proBNP. The standardized difference between normal and ischemic patients' stress-delta BNP values was -0.39 (95% confidence interval (CI): -0.61; -0.17) in a fixed-effects model and -0.73 (95% CI: -1.72; 0.28) in the random-effects model with high heterogeneity (I^2 = 94%, Q test P = 0.001). For NT-proBNP, the meta-analysis model showed no significant difference between the stress-delta test for ischemic and normal patients (standardized mean difference (SMD): -0.02, 95% CI: -0.31; 0.28). Patients without inducible ischemia appeared to have a lower baseline BNP and NT-proBNP compared to patients with inducible ischemia by stress testing. Although some studies report higher stress-delta BNP in the ischemic group, this pattern was not seen consistently across studies. There was high heterogeneity across studies which was not robust to sensitivity analysis. A random-effects model failed to find statistically significant differences in stress-delta BNP or NT-proBNP. Conclusions We failed to find a relationship between stress-delta BNP or NT-proBNP and the presence or absence of ischemia. This may be due to high heterogeneity in the underlying studies.

B-type natriuretic peptide predicts an ischemic etiology of acute heart failure in patients with stage 4-5 chronic kidney disease

OBJECTIVES

The non-invasive differentiation of ischemic and non-ischemic acute heart failure (AHF) not resulting from acute myocardial infarction is difficult and has therapeutic and prognostic implications. The aim of this study was to assess whether plasma B-type natriuretic peptide (BNP) can identify ischemic etiology in patients with stage 4-5 chronic kidney disease (CKD) presenting with AHF.

DESIGN AND METHODS

We prospectively analyzed 61 patients. The diagnosis of ischemic AHF was confirmed by coronary angiography or stress myocardial perfusion imaging. Plasma levels of BNP were measured at admission (BNP1) and 48 h after admission (BNP2).

RESULTS

The mean age of the study patients was 67 years. In these patients, 70.5% had diabetes and 47.5% had dialysis-dependent CKD; 28 of these patients (45.9%) had an ischemic etiology with significantly higher concentrations of BNP1 and BNP2 than did patients without ischemia. The area under the receiver operating characteristic curve was 0.755 (P=0.001) for BNP1 and 0.868 (P<0.001) for BNP2 to detect ischemic etiology of AHF. Plasma BNP1 >2907 ng/L (odds ratio [OR], 10.9; 95% confidence interval [CI] 2.5-48.4; P=0.002) and BNP2 >2322 ng/L (OR 93.1, 95% CI 7.0-1238.7; P=0.001) were independently associated with an ischemic etiology of AHF.

CONCLUSIONS

Plasma BNP may represent a clinically useful non-invasive tool for identification of ischemic etiology of AHF in patients with stage 4-5 CKD.

A multicenter, prospective study to evaluate the use of contrast stress echocardiography in early menopausal women at risk for coronary artery disease: trial design and baseline findings

AIMS

This multisite prospective trial, Stress Echocardiography in Menopausal Women At Risk for Coronary Artery Disease (SMART), aimed to evaluate the prognostic value of contrast stress echocardiography (CSE), coronary artery calcification (CAC), and cardiac biomarkers for prediction of cardiovascular events after 2 and 5 years in early menopausal women experiencing chest pain symptoms or risk factors. This report describes the study design, population, and initial test results at study entry.

METHODS

From January 2004 through September 2007, 366 early menopausal women (age 54±5 years, Framingham risk score 6.51%±4.4 %, range 1%-27%) referred for stress echocardiography were prospectively enrolled. Image quality was enhanced with an ultrasound contrast agent. Tests for cardiac biomarkers [high-sensitivity C-reactive protein (hsCRP), atrial natriuretic protein (ANP), brain natriuretic protein (BNP), endothelin (ET-1)] and cardiac computed tomography (CT) for CAC were performed.

RESULTS

CSE (76% exercise, 24% dobutamine) was abnormal in 42 women (11.5%), and stress electrocardiogram (ECG) was positive in 22 women (6%). Rest BNP correlated weakly with stress wall motion score index (WMSI) (r=0.189, p<0.001). Neither hsCRP, ANP, endothelin, nor CAC correlated with stress WMSI. Predictors of abnormal CSE were body mass index (BMI), diabetes mellitus, family history of premature coronary artery disease (CAD), and positive stress ECG. Twenty-four women underwent clinically indicated coronary angiography (CA); 5 had obstructive (≥50%), 15 had nonobstructive (10%-49%), and 4 had no epicardial CAD.

CONCLUSIONS

The SMART trial is designed to assess the prognostic value of CSE in early menopausal women. Independent predictors of positive CSE were BMI, diabetes mellitus, family history of premature CAD, and positive stress ECG. CAC scores and biomarkers (with the exception of rest BNP) were not correlated with CSE results. We await the follow-up data.