PLASMA CARDIAC NATRIURETIC PEPTIDE DETERMINATION AS A SCREENING-TEST FOR THE DETECTION OF PATIENTS WITH MILD LEFT-VENTRICULAR IMPAIRMENT

Objective - To determine the usefulness of measuring the cardiac natri uretic peptides, atrial natriuretic factor, N-terminal pro-atrial natr iuretic factor, and brain natriuretic peptide, as screening tests for identifying patients with mild left ventricular impairment. Design - C ross-sectional evaluation of the diagnostic accuracy of the cardiac na triuretic peptides. Setting - Cardiac catheterisation unit, Norwegian central hospital. Patients - A consecutive series of 254 patients unde rgoing diagnostic left-sided cardiac catheterisation. One hundred and twenty eight of these patients had a history of previous myocardial in farction. Main outcome measures - The presence of normal and impaired left ventricular function, as evaluated by logistic regression analysi s and estimation of the area under the receiver operating characterist ic (ROC) curve (an index of overall diagnostic accuracy). Ventricular function was assessed by the measurement of left ventricular end diast olic pressure and angiographically determined left ventricular ejectio n fraction. Results - Logistic regression analysis showed that plasma brain natriuretic peptide was the best predictor of increased left ven tricular end diastolic pressure (greater than or equal to 15 mm Hg) (P < 0.001), decreased left ventricular ejection fraction (less than or equal to 45%) (P < 0.001), and the combination of left ventricular eje ction fraction less than or equal to 45% and left ventricular end dias tolic pressure greater than or equal to 15 mm Hg (P < 0.001). The area s under the ROC function for the detection of left ventricular dysfunc tion were 0.789 for brain natriuretic peptide, 0.665 for atrial natriu retic factor, and 0.610 for N-terminal pro-atrial natriuretic factor. Conclusions - Plasma brain natriuretic peptide seemed to be a better i ndicator of left ventricular function than plasma atrial natriuretic f actor or N-terminal pro-atrial natriuretic factor. However, the overal l diagnostic accuracy of circulating atrial natriuretic factor, N-term inal pro-atrial natriuretic factor, and brain natriuretic peptide as i ndicators of normal and impaired ventricular function in an unselected group of patients with coronary heart disease and a high frequency of previous myocardial infarction was relatively modest.