Inducible myocardial ischaemia in asymptomatic Type 2 diabetic patients

Abstract

Background: to define the prevalence of inducible myocardial ischaemia in asymptomatic Type 2 diabetic patients and its relation to urinary albumin excretion rate (AER). Methods: 98 Type 2 diabetic patients aged 56±7 years, and 20 non-diabetic volunteers were recruited. Dypiridamole plus exercise thallium-201 myocardial single photon emission computed tomography (SPECT) was performed in all participants. Exclusion criteria were: age <30 or >70 years, evidence of cardiovascular disease, anomalous ECG, autonomic neuropathy or serum creatinine level >177 μmol/l. Results: 36 out of 98 diabetic patients (37%) showed abnormal thallium SPECT (considered as inducible myocardial ischaemia), versus one out of 20 (5%) in control group (odds ratio 7.3 (95% CI 1.1–50.5), P<0.005). Among diabetic patients, prevalence of inducible ischaemia was greater in those with higher urinary AER (AER <30:30–300:> 300 mg/24 h: 26: 53: 88%, and greater in the normoalbuminuric group compared to the control group (26 vs. 5%; P<0.05). An AER >30 mg/24 h was the only independent factor associated with inducible myocardial ischaemia in the multivariate analysis ( P=0.009). Conclusions: raised urinary AER in asymptomatic diabetic patients is a risk factor for present myocardial ischaemia demonstrated by thallium dypiridamole tomography. The prevalence of inducible myocardial ischaemia in asymptomatic diabetic patients without known coronary disease is much higher than in non-diabetic population.