Comparative sensitivities between different plasma B-type natriuretic peptide assays in patients with minimally symptomatic heart failure

Cut-off values of B-type natriuretic peptide for the diagnosis of congestive heart failure in patients with dyspnoea visiting emergency departments: a study on Korean patients visiting emergency departments

OBJECTIVES

To determine the optimal cut-off values of B-type natriuretic peptide (BNP) for the diagnosis of congestive heart failure (CHF) in 1040 Korean patients with dyspnoea visiting emergency departments.

METHODS

BNP values were measured for 662 patients without CHF to examine whether significant relationships existed between the BNP values and age, gender or underlying disease. In 378 patients with CHF, a similar analysis was performed in addition to the examination of the relationship between the mean BNP values and CHF severity.

RESULTS

The optimal threshold for the detection of heart failure was a BNP concentration of 296.5 pg/mL, regardless of age, sex and underlying disease among the Korean study population. In the non-CHF patients, women showed significantly higher mean BNP values than did men. Further, in these patients, the mean BNP values of men with underlying disease (hypertension, angina pectoris, chronic renal failure, chronic obstructive pulmonary disease) and those with at least two underlying diseases, one of which was hypertension, was higher than those without underlying disease, whereas no difference was observed between women with and without underlying disease. Based on the New York Heart Association classification, echocardiography findings and mortality rate of the CHF patients, the BNP value was found to be related to both the severity of heart failure and its prognosis.

CONCLUSIONS

The BNP concentration used for the diagnosis of CHF in Korean people is considerably higher than the normal cut-off value of 100 pg/mL. In the non-CHF patients, the BNP values of women were influenced less by underlying disease. This suggests that the factors that influence BNP values in women are different from those in men.

B-type natriuretic peptide: a critical review

Natriuretic peptides have been used as tools for diagnosis and risk stratification in patients with heart failure, myocardial infarction, and unstable coronary syndromes, as well as in the general population. The biology of intra-assay and intraindividual variations of plasma natriuretic peptide levels is still not clearly understood despite their broad adoption in clinical practice. Interpretation of plasma natriuretic peptide levels therefore requires availability of the clinical context as well as considerations of various confounders. It is clear that high plasma natriuretic peptide levels can be highly suggestive of underlying myocardial disease, although a specific underlying cause cannot be identified based on the test results. The potential use of natriuretic peptide levels to monitor and guide patient management or detect subclinical disease states is currently under investigation.

Relation of brain natriuretic peptide levels to cognitive dysfunction in adults > 55 years of age with cardiovascular disease

Cardiovascular disease (CVD) is associated with cognitive deficits long before the onset of stroke or dementia. Recent work has extended these findings and shown that patients with congestive heart failure also exhibit reduced cognitive performance. Brain natriuretic peptide (BNP) is used to help diagnose heart failure, but no study has examined whether BNP predicts cognitive dysfunction in older patients with CVD. BNP values and performance on the Dementia Rating Scale were assessed in 56 older adults with documented CVD. Forty-eight percent of the participants were women, and their average age was 70 +/- 8 years. All participants had Mini-Mental State Examination scores greater than the cutoff for dementia and no histories of neurologic or severe psychiatric disorders. The average BNP level was 122 +/- 202 pg/ml. Hierarchical regression analyses showed that log-transformed BNP levels predicted Dementia Rating Scale total score after adjusting for possible demographic and medical confounders (DeltaR2 = 0.09, F[1, 44] = 6.14, p = 0.017). Partial correlation analysis adjusting for these possible confounders showed a particularly strong relation to the conceptualization subtest (r = -0.44, p = 0.002), a measure of verbal and nonverbal abstraction abilities. In conclusion, the results of the present study provide the first evidence for an independent relation between BNP and cognitive dysfunction in older adults with CVD.

Assessment of cardiac risk before non-cardiac surgery: brain natriuretic peptide in 1590 patients

OBJECTIVE

To evaluate the predictive value of brain natriuretic peptide (BNP) for assessment of cardiac risk before non-cardiac surgery.

METHODS

Consecutively treated patients (947 men, 643 women) whose BNP was measured before non-cardiac surgery were studied. Clinical and ECG variables were evaluated to identify predictors of postoperative cardiac events.

RESULTS

Events occurred in 6% of patients: 21 cardiac deaths, 20 non-fatal myocardial infarctions, 41 episodes of pulmonary oedema and 14 patients with ventricular tachycardia. All of these patients had raised plasma BNP concentrations (best cut-off point 189 pg/ml). The only independent predictor of postoperative events was BNP (odds ratio 34.52, 95% confidence interval (CI) 17.08 to 68.62, p < 0.0001). Clinical variables of Goldman's multifactorial index identified 18% of patients in class I, 40% in class II, 24% in class III and 18% in class IV preoperatively; postoperative event rates were 2%, 3%, 7% and 14%, respectively. BNP identified 60% of patients as having zero risk (BNP 0-100 pg/ml), 22% low risk (101-200 pg/ml), 14% intermediate risk (201-300 pg/ml) and 4% high risk (> 300 pg/ml); postoperative event rates were 0%, 5%, 12% and 81%, respectively.

CONCLUSIONS

In this population of patients evaluated before non-cardiac surgery, BNP is an independent predictor of postoperative cardiac events. BNP > 189 pg/ml identified patients at highest risk.