Diabetic background retinopathy is associated with impaired coronary vasoreactivity in people with Type 1 diabetes.
OBJECTIVE
We examined whether diabetic background retinopathy is associated with reduced coronary vasoreactivity in people with Type 1 diabetes.


METHODS
A total of 21 men with Type 1 diabetes were investigated, including 9 men with background retinopathy and 12 men without retinopathy. In addition, 12 non-diabetic, age-matched subjects were studied. All subjects were non-smokers, otherwise healthy and had no other diabetic complications. Resting myocardial blood flow and hyperaemic dipyridamole-stimulated flow (dipyridamole, 0.56 mg/kg during a 4-min period), a measure of coronary vasoreactivity, were measured during euglycaemic hyperinsulinaemic clamp (1 mU x kg(-1) x min(-1)) using positron emission tomography and oxygen-15-labelled water.


RESULTS
Resting myocardial blood flow (0.82 +/- 0.13 vs 0.96 +/- 0.23 vs 0.88 +/- 0.25 ml x g(-1) x min(-1), with vs without retinopathy vs non-diabetic subjects) and coronary vascular resistance (111.2 +/- 23.4 vs 95.5 +/- 15.8 vs 101.9 +/- 31.5 mmHg x min x g x ml(-1) respectively) were not significantly different between the groups. Dipyridamole infusion induced an increase in blood flow and a decrease in coronary vascular resistance in all study subjects (p<0.001). However, dipyridamole-stimulated flow and coronary vascular resistance were blunted in diabetic patients with retinopathy (2.9 +/- 0.9 ml x g(-1) x min(-1) and 34.1 +/- 11.3 mmHg x min x g x ml(-1)) when compared to diabetic patients without retinopathy (4.0 +/- 1.3 ml x g(-1) x min(-1), p=0.04 and 24.6 +/- 7.5 mmHg x min x g x ml(-1), p=0.03) or non-diabetic subjects (4.5 +/- 1.4 ml x g(-1) x min(-1) p=0.008 and 22.2 +/- 8.7 mmHg x min x g x ml(-1), p=0.01). Myocardial flow reserve was impaired in diabetic patients with retinopathy (3.6 +/- 1.0) when compared to non-diabetic subjects (5.3 +/- 1.9, p=0.02) but not significantly reduced when compared to diabetic patients without retinopathy (4.2 +/- 1.4, p=0.2).


CONCLUSIONS
Diabetic background retinopathy appears to be associated with impaired coronary vasoreactivity in young people with Type 1 diabetes.
Sundell
J
J
Turku PET Centre, Turku University Central Hospital, Turku, Finland. jan.sundell@utu.fi
Janatuinen
T
T
Rönnemaa
T
T
Raitakari
O T
OT
Toikka
J
J
Nuutila
P
P
Knuuti
J
J
D000328:Adult; D001341:Autonomic Nervous System / Q000503:physiopathology; D001794:Blood Pressure / Q000502:physiology; D003326:Coronary Circulation / Q000187:drug effects / Q000502:physiology; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000503:physiopathology*; D003922:Diabetes Mellitus, Type 1 / Q000503:physiopathology*; D003930:Diabetic Retinopathy / Q000150:complications* / Q000000981:diagnostic imaging; D004176:Dipyridamole; D005260:Female; D015309:Glucose Clamp Technique; D006442:Glycated Hemoglobin / Q000378:metabolism; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D010104:Oxygen Radioisotopes; D049268:Positron-Emission Tomography; D012307:Risk Factors; D014655:Vascular Resistance / Q000502:physiology; D014665:Vasodilator Agents
D004176:Dipyridamole; D006442:Glycated Hemoglobin; D010104:Oxygen Radioisotopes; D014665:Vasodilator Agents