B-type natriuretic peptide in the diagnosis of cardiac disease in elderly day hospital patients.

OBJECTIVES

heart failure is primarily a disease of elderly people. Current guidelines suggest all patients with suspected heart failure should undergo objective assessment, usually by echocardiography. In the UK resources are limited and not all patients have access to echocardiography. The electrocardiogram is widely used as a pre-screening investigation. Recently the natriuretic peptides have been shown to correlate well with left ventricular function, and evidence is accumulating which suggests that B-type natriuretic peptide may have a role in detecting cardiovascular disease. Elderly patients attending day hospital often have non-specific cardiovascular symptoms. B-type natriuretic peptide measurement in parallel with conventional electrocardiogram, may offer a novel method of identifying those with significant cardiac disease, which may warrant treatment. This study assessed the role of B-type natriuretic peptide and electrocardiogram in the detection of cardiac disease in patients attending Day Hospital.

DESIGN

prospective cohort study of patients referred to Day Hospital with suspected cardiovascular disease.

METHODS

this study prospectively evaluated 299 consecutive patients attending day hospital over a period of 13 months. Patients underwent clinical assessment, electrocardiography, echocardiography and natriuretic peptide measurement. Objective evidence of cardiac disease was based on electrocardiogram and echocardiographic findings.

SETTING

Medicine for the Elderly Day Hospital, Royal Victoria Hospital, Dundee.

MAIN OUTCOME MEASURES

sensitivity, specificity, positive and negative predictive values of screening tests for left ventricular systolic dysfunction. Receiver-Operating-Characteristic curves for ability of B-type natriuretic peptide to detect cardiac disease (including left ventricular systolic dysfunction, valvular disease, atrial fibrillation and left ventricular hypertrophy). Mean B-type natriuretic peptide levels with 'incremental' levels of cardiovascular disease.

RESULTS

299 patients (mean age 79; 65% female) completed the assessment. Ten percent of patients had left ventricular systolic dysfunction but 50% had objective evidence of cardiac disease. B-type natriuretic peptide was significantly elevated in patients with left ventricular systolic dysfunction, atrial fibrillation, left ventricular hypertrophy and valvular disease. Both B-type natriuretic peptide and the electrocardiogram were sensitive in detecting left ventricular systolic dysfunction but lacked specificity. Combining B-type natriuretic peptide with the electrocardiogram improved detection of left ventricular systolic dysfunction. B-type natriuretic peptide levels increased progressively as the number of different cardiac abnormalities increased.

CONCLUSIONS

B-type natriuretic peptide may be a useful marker for cardiac disease in patients attending Day Hospital. Half of the patients assessed had cardiac disease detected. Both the electrocardiogram and B-type natriuretic peptide were sensitive in the detection of left ventricular systolic dysfunction but lacked specificity. B-type natriuretic peptide was superior to the electrocardiogram in the detection of valvular disease. If used to pre-screen cardiovascular disease in Day Hospital patients, B-type natriuretic peptide and the electrocardiogram could reduce the need for echocardiography in some patients before implementing evidence-based treatments. B-type natriuretic peptide increases progressively as the number of different cardiac abnormalities increases and this may explain why B-type natriuretic peptide is of such prognostic value in older patients.