Coronary flow reserve, insulin resistance and blood pressure response to standing in patients with normoglycaemia: is there a relationship?
OBJECTIVE
To establish the relationships between coronary flow reserve, cardiovascular autonomic function, and insulin resistance characterized by the homeostasis model assessment insulin resistance score in patients with normal carbohydrate metabolism according to the World Health Organization (WHO) and American Diabetes Association (ADA) criteria, and with morphologically normal epicardial coronary arteries.


METHODS
Twenty-five patients [12 women and 13 men, mean (sd) age: 53 +/- 11 years] with normal coronary angiography were enrolled into the study. Coronary flow reserve was measured during stress transoesophageal echocardiography. Autonomic dysfunction was assessed by means of five standard cardiovascular reflex tests. The fasting serum glucose and insulin levels were determined and the homeostasis assessment model insulin resistance score was calculated.


RESULTS
In patients with normal carbohydrate metabolism, negative correlations were observed between the coronary flow reserve and both the serum insulin level (r = -0.445, P = 0.026) and the homeostasis assessment model insulin resistance score (r = -0.449, P = 0.024). The systolic blood pressure response to standing also correlated with the coronary flow reserve (r = -0.519, P = 0.011). The heart rate response to deep breathing, the Valsalva ratio, the 30/15 ratio and the sustained handgrip test results were not correlated with the coronary flow reserve.


CONCLUSIONS
Our data suggest the possible role of insulin resistance and early sympathetic nerve dysfunction in the development of decreased coronary flow reserve in patients without diabetes mellitus or impaired glucose tolerance.
Nemes
A
A
First Department of Medicine, Medical Faculty, Albert Szent-Györgyi Medical and Pharmaceutical Centre, University of Szeged, Korányi fasor 10, H-6720 Szeged, Hungary.
Lengyel
C
C
Forster
T
T
Várkonyi
T T
TT
Takács
R
R
Nagy
I
I
Kempler
P
P
Lonovics
J
J
Csanády
M
M
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D001794:Blood Pressure / Q000502:physiology*; D003326:Coronary Circulation / Q000502:physiology*; D004452:Echocardiography; D005260:Female; D006706:Homeostasis / Q000502:physiology; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D008875:Middle Aged
D001786:Blood Glucose