Low whole-body insulin sensitivity in patients with ischaemic heart disease is associated with impaired myocardial glucose uptake predictive of poor outcome after revascularisation

Abstract

We tested the hypothesis that low whole-body insulin sensitivity in patients with ischaemic heart disease and impaired left ventricular (LV) function is associated with abnormalities of insulin-mediated myocardial glucose uptake affecting outcome after coronary bypass surgery (CABG). We studied 29 patients with ischaemic heart disease and impaired LV ejection fraction (EF) and age-matched healthy volunteers ( n = 30). As assessed by euglycaemic glucose-insulin clamp, 15 patients had a low and 14 a normal whole-body insulin sensitivity. Using positron emission tomography, patterns of fluorine-18 fluorodeoxyglucose and nitrogen-13 ammonia uptake in addition to quantified glucose uptake, blood flow and hyperaemic blood flow were assessed before CABG in 16 myocardial segments of the left ventricle. Major adverse cardiac events and LVEF were evaluated 7 months after CABG. Glucose uptake in normokinetic PET-normal myocardium was found to be higher in patients with normal whole-body insulin sensitivity ( P < 0.001), whereas in patients with low whole-body insulin sensitivity more segments displayed a pattern of reduced glucose uptake in normoperfused myocardium (PET-reverse mismatch) ( P < 0.05). Hyperaemic blood flow was impaired in both patient groups. A major cardiac event after CABG could partly be predicted by the LV extent of normoperfused segments with PET-reverse mismatch. We conclude that low whole-body insulin sensitivity in patients with ischaemic heart disease and impaired LV function is associated with impaired insulin-mediated myocardial glucose uptake, which is partially predictive of a worse outcome after CABG.

Effects of High Thoracic Epidural Analgesia on Myocardial Blood Flow in Patients With Ischemic Heart Disease

“…As expected, the highest hyperemic blood flow was found in myocardium subtended by nonstenotic vessels, and as previously reported, hyperemic blood flow was significantly lower than in age-matched healthy subjects. 29 This finding probably reflects the inability of coronary angiography to detect early phases of atherosclerosis and an overall impairment of vasomotor function in patients with ischemic heart disease.…”

Variability of insulin-stimulated myocardial glucose uptake in healthy elderly subjects

“…Heart positioning and attenuation correction were performed in the same way as in the 18 F-FDG study. Dynamic image acquisition for each 13 NH 3 injection was performed for a total scan duration of 20 min [7]. Heart rate and blood pressure were measured at intervals of 30 s within the first 2 min of the scan.…”

“…Positioning of the heart in the tomograph was performed using a 2-min transmission scan, followed by a 20-min transmission scan to correct for photon attenuation. For determination of myocardial glucose uptake, 300 MBq 18 F-FDG was infused intravenously over 30 s and dynamic image acquisition was performed for a total scan duration of 60 min [7]. Plasma blood glucose concentration, heart rate and blood pressure were measured every 15 min during the scan.…”

“…Insulin-stimulated myocardial glucose uptake during euglycaemic glucose clamp, myocardial blood flow at rest and dipyridamole-induced hyperaemic blood flow were quantified using 18 F-FDG and nitrogen-13 ammonia ( 13 NH 3 ) as previously described [7].…”

“…Measurement of absolute myocardial glucose uptake has provided important insights into the pathophysiology of myocardial ischaemia [4,5,6,7]. However, in patients with ischaemic heart disease, substantial variability of glucose uptake in normally contracting myocardium appears to limit the diagnostic value of the method for the identification of ischaemically jeopardised but viable myocardium [8,9].…”