Plasma N-terminal pro-brain natriuretic peptide levels identifying left ventricular diastolic dysfunction in patients with preserved ejection fraction.

BACKGROUND Diagnosis of left ventricular (LV) diastolic dysfunction by blood testing is expedient in the clinical setting. METHODS AND RESULTS In 98 patients with LV ejection fraction ≥50% who underwent cardiac catheterization for evaluation of coronary artery disease, LV pressure (LVP) was measured using a catheter-tipped micromanometer. A time constant, τ, of LV relaxation was computed from LVP decay; the inertia force (IF) of late systolic aortic flow, a surrogate index of LV elastic recoil, was also computed from the LVP-dP/dt relation (phase loop). Patients were classified into 2 groups: those with impaired LV relaxation (τ ≥48 ms) and those with preserved LV relaxation (τ <48 ms). Patients were also classified into another 2 groups: those with IF (≥0.5 mmHg) and those without (<0.5 mmHg). Plasma N-terminal pro-brain natriuretic peptide (NT-proBNP) ≥56.5 pg/ml had a sensitivity of 100%, specificity of 52.5%, and negative predictive value of 100% for identifying impaired LV relaxation. NT-proBNP ≥244.5 pg/ml had a sensitivity of 62.5% and specificity of 93.9% for detecting lack of IF. CONCLUSIONS NT-proBNP level <56.5 pg/ml could be used as a value to sensitively identify patients with preserved LV systolic and diastolic function among those with coronary artery disease. NT-proBNP level ≥244.5 pg/ml is able to specifically detect a lack of IF and has potential for specifically diagnosing LV isolated diastolic dysfunction.