B-type natriuretic peptide can detect silent myocardial ischaemia in asymptomatic type 2 diabetes.

OBJECTIVE

To find out whether B-type natriuretic peptide (BNP) detects silent myocardial ischaemia in patients with type 2 diabetes, since many of these patients have silent ischaemia leading to unexpected cardiac deaths.

DESIGN

Prospective cross-sectional study with consecutive recruitment of patients.

SETTING

Outpatient, single centre.

PATIENTS: 219 patients with type 2 diabetes. Patients were excluded if they had a history or evidence of cardiac failure.

OUTCOME MEASURES: BNP, echocardiography and exercise tolerance test (ETT). BNP was compared with the ETT result in all patients and specifically in those who had no apparent ischaemic heart disease (IHD).

RESULTS

121 patients had no history of IHD or cardiac failure and of these patients 85 had a clearly abnormal or normal ETT result. BNP was higher in patients with an abnormal than with a normal ETT (mean 58.2 (SD 46.3) v 24.4 (SD 15.7) pg/ml, p < 0.001). In univariate analysis BNP was an independent predictor of an abnormal ETT (p < 0.001). In multivariate analysis BNP remained an independent predictor of the ETT result. BNP concentration over 20 pg/ml predicted an abnormal ETT result with a sensitivity of 87% and specificity of 37%, and BNP over 40 pg/ml had a sensitivity of 63% and a specificity of 81%.

CONCLUSION

BNP is of value in predicting silent ischaemia on exercise testing in asymptomatic patients with type 2 diabetes.