Dept Cardiology, Bispebjerg University Hospital, Copenhagen, Denmark.
Cardiovasc Diabetol. 2012 Aug 13;11:97. doi: 10.1186/1475-2840-11-97.
Insulin resistance has been linked to exercise intolerance in heart failure patients. The aim of this study was to assess the potential role of coronary flow reserve (CFR), endothelial function and arterial stiffness in explaining this linkage.
39 patients with LVEF < 35% (median LV ejection fraction (LVEF) 31 (interquartile range (IQ) 26-34), 23/39 of ischemic origin) underwent echocardiography with measurement of CFR. Peak coronary flow velocity (CFV) was measured in the LAD and coronary flow reserve was calculated as the ratio between CFV at rest and during a 2 minutes adenosine infusion. All patients performed a maximal symptom limited exercise test with measurement of peak oxygen uptake (VO(2)peak), digital measurement of endothelial function and arterial stiffness (augmentation index), dual X-ray absorptiometry scan (DEXA) for body composition and insulin sensitivity by a 2 hr hyperinsulinemic (40 mU/min/m(2)) isoglycemic clamp.
Fat free mass adjusted insulin sensitivity was significantly correlated to VO(2)peak (r = 0.43, p = 0.007). Median CFR was 1.77 (IQ 1.26-2.42) and was correlated to insulin sensitivity (r 0.43, p = 0.008). CFR (r = 0.48, p = 0.002), and arterial stiffness (r = -0.35, p = 0.04) were correlated to VO(2)peak whereas endothelial function and LVEF were not (all p > 0.15). In multivariable linear regression adjusting for age, CFR remained independently associated with VO2peak (standardized coefficient (SC) 1.98, p = 0.05) whereas insulin sensitivity (SC 1.75, p = 0.09) and arterial stiffness (SC -1.17, p = 0.29) were no longer associated with VO2peak.
The study confirms that insulin resistance is associated with exercise intolerance in heart failure patients and suggests that this is partly through reduced CFR. This is the first study to our knowledge that shows an association between CFR and exercise capacity in heart failure patients and links the relationship between insulin resistance and exercise capacity to CFR.
胰岛素抵抗与心力衰竭患者的运动耐量受损有关。本研究旨在评估冠状动脉血流储备（CFR）、内皮功能和动脉僵硬度在解释这种相关性方面的潜在作用。
39 名左心室射血分数（LVEF）<35%的患者（中位数 LVEF 31（四分位距 26-34），23/39 为缺血性起源）接受超声心动图检查，并测量 CFR。在 LAD 中测量峰值冠状动脉血流速度（CFV），并计算 CFV 在休息时和在 2 分钟腺苷输注时的比值作为 CFR。所有患者均进行最大症状限制运动试验，测量峰值摄氧量（VO 2peak）、内皮功能和动脉僵硬度（增强指数）的数字测量值、双能 X 线吸收法（DEXA）进行身体成分和胰岛素敏感性测量由 2 小时高胰岛素（40mU/min/m 2）等血糖钳夹。
去脂体重校正后的胰岛素敏感性与 VO 2peak 显著相关（r=0.43，p=0.007）。中位数 CFR 为 1.77（四分位距 1.26-2.42），与胰岛素敏感性相关（r=0.43，p=0.008）。CFR（r=0.48，p=0.002）和动脉僵硬度（r=-0.35，p=0.04）与 VO 2peak 相关，而内皮功能和 LVEF 则不相关（均 p>0.15）。在多元线性回归中，调整年龄后，CFR 仍然与 VO 2peak 独立相关（标准化系数（SC）1.98，p=0.05），而胰岛素敏感性（SC 1.75，p=0.09）和动脉僵硬度（SC-1.17，p=0.29）与 VO 2peak 不再相关。
本研究证实，胰岛素抵抗与心力衰竭患者的运动耐量受损有关，并提示这在一定程度上是由于 CFR 降低所致。这是我们所知的第一项表明 CFR 与心力衰竭患者的运动能力之间存在关联，并将胰岛素抵抗与运动能力之间的关系与 CFR 联系起来的研究。
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