N-terminal pro-B-type natriuretic peptide and diastolic function measurements by adenosine stress echocardiography in prediction of coronary stenosis in patients.

BACKGROUND: Stress echocardiography is mainly used in detection of coronary artery disease (CAD) and to assess risk. This study aimed to use adenosine stress echocardiography (ASE) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) to noninvasively assess coronary stenosis in patients with chest pain syndromes or anginal equivalent.

METHODS: NT-proBNP was measured after overnight fast in fifty patients, 42 males and 8 females, who were (57 ± 11) years old. They then underwent echocardiography before and during adenosine administration. Left ventricular (LV) diastolic function analyzed included mitral annular early (E') and late velocity (A') both at the mitral septal and lateral level and the mitral inflow to annulus ratio (E/E'). Coronary angiography was performed the following day after which patients were assigned to three groups: normal results (16 patients), stenosis 50% - 69% (17 patients) and stenosis ≥ 70% (17 patients).

RESULTS: NT-proBNP levels in the groups of stenosis 50% - 69% and ≥ 70% were significantly higher than that in the group with normal results (P = 0.014 and P = 0.040). During adenosine stress, the E/E' in the group of stenosis ≥ 70% was higher than in the group of normal results (P = 0.024). E'(lateral)/A'(lateral) in the group of stenosis 50% - 69% and E'(septal)/A'(septal) and E'(lateral)/A'(lateral) in the group of stenosis ≥ 70% were also decreased during stress compared with baseline (P = 0.003, P = 0.001, P = 0.022). The variation of E'(septal)/A'(septal) before and during adenosine stress (ΔE'(septal)/A'(septal)) between the groups of normal results and stenosis ≥ 70% were significantly different (P = 0.001). By receiver operating characteristic (ROC), the specificity of ΔE'(septal)/A'(septal) ≥ 0.037 predicting coronary stenosis < 70% was 94%. The sensitivity and specificity of NT-proBNP ≥ 544.6 fmol/ml in predicting coronary stenosis ≥ 70% were 93% and 75%, respectively. NT-proBNP inversely correlated with E'(lateral)/A'(lateral) (r = - 0.390, P = 0.014) and positively correlated with E/E'(lateral) (r = 0.550, P = 0.001).

CONCLUSIONS: Adenosine might induce diastolic dysfunction in patients with coronary stenosis more than 70% and NT-proBNP could reflect LV diastolic function to a certain extent. We support the prediction that most patients having chest pain syndromes or anginal equivalent with NT-proBNP < 544.6 fmol/ml and in ASE ΔE'(septal)/A'(septal) ≥ 0.037 might be spared coronary angiography.