Reduced Myocardial Flow Reserve in Non–Insulin-Dependent Diabetes Mellitus

Objectives. We analyzed myocardial flow reserve (MFR) in patients with non–insulin-dependent (type II) diabetes mellitus (NIDDM) without symptoms and signs of ischemia. Background. Diminished MFR in diabetes has been suggested. However, it remains controversial whether MFR is related to glycemic control, mode of therapy or gender in NIDDM. Methods. Myocardial blood flow (MBF) was measured at baseline and during dipyridamole loading in 25 asymptomatic, normotensive, normocholesterolemic patients with NIDDM and 12 age-matched control subjects by means of positron emission tomography and nitrogen-13 ammonia, after which MFR was calculated. Results. Baseline MBF in patients with NIDDM ([mean ± SD] 74.0 ± 24.0 ml/min per 100 g body weight) was comparable to that in control subjects (73.0 ± 17.0 ml/min per 100 g). However, MBF during dipyridamole loading was significantly lower in patients with NIDDM (184 ± 99.0 ml/min per 100 g, p < 0.01) than in control subjects (262 ± 120 ml/min per 100 g), as was MFR (NIDDM: 2.77 ± 0.85; control subjects: 3.8 ± 1.0, p < 0.01). significantly decreased MFR was seen in men (2.35 ± 0.84) compared with women with NIDDM (3.18 ± 0.79, p < 0.05); however, no significant differences were found in terms of age, hemoglobin a1c and baseline MBF. MFR was comparable between the diet (2.78 ± 0.80) and medication therapy groups (2.76 ± 0.77) and was inversely correlated with average hemoglobin A1c for 5 years (r = −0.55, p < 0.01) and fasting plasm glucose concentration (r = −0.57, p < 0.01) but not age or lipid fractions. Conclusions. Glycemic control and gender, rather than mode of therapy, is related to MFR in NIDDM.