Predictors of B-type natriuretic peptide and left atrial volume index in patients with preserved left ventricular systolic function: an echocardiographic-catheterization study.

BACKGROUND: B-type natriuretic peptide (BNP) and left atrial volume index (LAVi) are used as surrogate measures for global myocardial function and are recommended for the diagnosis of heart failure with normal ejection fraction. Little is known, however, about predictors in patients with preserved systolic function.

AIMS: To identify factors that influence the relation of BNP and left atrial size to invasively determined left ventricular end-diastolic pressure in stable patients with preserved left ventricular systolic function.

METHODS: Fifty-nine consecutive patients were included prospectively. Clinical, biological, Doppler echocardiographic and invasive variables were collected simultaneously.

RESULTS: BNP was predicted independently by left ventricular ejection fraction, diastolic function and age (p<0.05). LAVi was predicted independently by left ventricular mass index and invasive left ventricular end-diastolic pressure (p<0.01). BNP predicted increased left ventricular end-diastolic pressure greater than 16 mmHg (p=0.004); the optimal cut-off value was 33 pg/mL (area under the receiver-operating characteristic curve [AUC] 0.74 [0.6-0.84], p<0.001, sensitivity 72%, specificity 70%). LAVi predicted increased left ventricular end-diastolic pressure (p<0.001); the optimal cut-off value for LAVi was 26 mL/m(2) (AUC 0.87 [0.75-0.94], p<0.001; sensitivity 85%, specificity 80%). Unlike BNP (p=0.1), LAVi performed well in patients with abnormal relaxation at mitral filling (p<0.01).

CONCLUSION: BNP is influenced by age in stable patients with preserved systolic function and should be interpreted cautiously. LAVi is a powerful surrogate for invasively determined left ventricular end-diastolic pressure regardless of age and mitral filling.