title: Impairment of coronary microvascular dilation in response to cold pressor--induced sympathetic stimulation in type 2 diabetic patients with abnormal stress thallium imaging.
abstract: Coronary microcirculation dysfunction may be associated with myocardial perfusion defects on thallium imaging in diabetic patients without coronary artery stenosis. Microvascular coronary adaptation to increased myocardial oxygen demand in response to sympathetic stimulation evoked by the cold pressor test was examined in 22 type 2 diabetic patients with thallium imaging defects and in 15 control subjects. Both the diabetic patients and control subjects had angiographically normal coronary arteries and no other risk factors. Despite a similar increase in the rate-pressure product in the two groups (22.6 +/- 12.4% in diabetic patients and 31.8 +/- 8.2% in control subjects, NS), coronary blood flow increase in the left anterior descending artery (mean flow velocity measured by intracoronary Doppler multiplied by the cross-sectional area measured by digital angiography) was significantly lower in diabetic patients than in control subjects (14.7 +/- 19.8 vs. 75.5 +/- 13.5%, respectively; P = 0.0001). In addition, when there was a positive correlation between the two parameters in control subjects (r = 0.651, P < 0.01), there was no relationship in diabetic patients (r = 0.054). In conclusion, vasodilation of the coronary microcirculation in response to sympathetic stimulation evoked by the cold pressor test is impaired in type 2 diabetic patients without epicardial artery lesions. This microvascular impairment during sympathetic stimulation may explain exercise-induced myocardial perfusion abnormalities observed in these patients and may impair microcirculatory coronary vasodilation during current life stress episodes such as exercise, mental stress, or cold exposition.
authors.affiliation: Department of Physiology and Functional Investigations, Louis Mourier Hospital, University Hospital Xavier-Bichat, Colombes, France. alain.nitenberg@lmr.ap-hop-paris.fr
authors.forename: A
authors.initials: A
authors.lastname: Nitenberg
authors.forename: S
authors.initials: S
authors.lastname: Ledoux
authors.forename: P
authors.initials: P
authors.lastname: Valensi
authors.forename: R
authors.initials: R
authors.lastname: Sachs
authors.forename: J R
authors.initials: JR
authors.lastname: Attali
authors.forename: I
authors.initials: I
authors.lastname: Antony
mesh_terms: D001783:Blood Flow Velocity; D001794:Blood Pressure; D003080:Cold Temperature; D017023:Coronary Angiography; D003326:Coronary Circulation / Q000502:physiology*; D003331:Coronary Vessels / Q000502:physiology / Q000503:physiopathology*; D003924:Diabetes Mellitus, Type 2 / Q000503:physiopathology*; D005260:Female; D006339:Heart Rate; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D017078:Laser-Doppler Flowmetry; D008297:Male; D008833:Microcirculation / Q000502:physiology*; D008875:Middle Aged; D012016:Reference Values; D012044:Regression Analysis; D012307:Risk Factors; D014664:Vasodilation / Q000502:physiology*