Elevated NT-proBNP and coronary calcium score in relation to coronary artery disease in asymptomatic type 2 diabetic patients with elevated urinary albumin excretion rate.

BACKGROUND

Elevated plasma N-terminal (NT)-proBNP levels and coronary calcium score (CCS) not only predicts myocardial ischaemia and coronary artery stenosis but also adverse cardiovascular events and mortality in type 2 diabetic patients with an increased urinary albumin excretion rate (UAER), whereas low levels are associated with low frequency of coronary artery disease (CAD) and good prognosis. The underlying causes of poor prognosis in patients with elevated NT-proBNP are not known; thus, we investigated the role of putative asymptomatic CAD in type 2 diabetic patients with UAER >30 mg/24 h and elevated P-NT-proBNP and/or CCS.

METHODS

We identified 200 type 2 diabetic patients without known CAD and with normal creatinine levels. Patients with P-NT-proBNP >45.2 ng/L (the median P-NT-proBNP value in this cohort and in accordance with our previous findings) and/or CCS ≥ 400 were stratified as high-risk patients for CAD (n = 133) and all other patients as low-risk patients (n = 67). High-risk patients were examined by myocardial perfusion imaging (MPI; n = 109) and/or computer tomography angiography (n = 20) and/or coronary angiography (CAG; n = 86).

RESULTS

All patients received intensive mulitifactorial intervention. In 70 of 133 (53%) high-risk patients, significant CAD was demonstrated by MPI and/or CAG, corresponding to 35% (70/200) of the total cohort. Among high-risk patients, CCS but not P-NT-proBNP was paralleled by increased prevalence of significant CAD and in the 86 patients where CAG was performed, a CCS <100 had a negative predictive value for coronary artery stenosis of 94% (P = 0.04).

CONCLUSIONS

Our study revealed that >50% of asymptomatic type 2 diabetic patients with UAER >30 mg/24 h had significant CAD based on risk stratification with P-NT-proBNP and CCS. This provides some explanation to the previously reported poor prognosis in these asymptomatic patients. Optimized cardio protective treatment in these patients is warranted.