Mazzadi Alejandro N, Janier Marc F, Brossier Benjamin, André-Fouët Xavier, McFadden Eugene, Revel Didier, Croisille Pierre
Unité Mixte de Recherche-Centre National de la Recherche Scientifique 5515, Centre de Recherche et d'Applications en Traitement de l'Image et du Signal, Lyon, France.
Am J Physiol Heart Circ Physiol. 2004 May;286(5):H1946-53. doi: 10.1152/ajpheart.00704.2003. Epub 2004 Jan 15.
The impact of blood flow reductions on the intramyocardial inotropic reserve has not yet been established in coronary artery disease (CAD). We therefore evaluated in severe CAD the relationship between positron emission tomography (PET) patterns of perfusion and glucose uptake and the corresponding tagged magnetic resonance imaging (tagged MRI) values of midmyocardial strains under low-dose dobutamine. Eighteen patients underwent tagged MRI (at rest, with dobutamine) and H2(15)O/18F-fluorodeoxyglucose PET. Regional midmyocardial circumferential shortening (Ecc) and PET patterns (normal, match viable, mismatch viable, and infarcted) were assessed in three tagged MRI/PET short-axis slices. Regional Ecc at rest correlated with both perfusion (r = 0.49) and glucose uptake (r = 0.58). The presence of the inotropic reserve was similar in normal, match viable, and infarcted (approximately 40% of regions vs. 52% in mismatch viable, P < 0.05), but the extent of the increase after dobutamine was lower in infarcted regions (P = 0.06). Within each PET pattern, regions were grouped according to their Ecc values at rest into three categories (high, intermediate, and low contractile performance). In mismatch viable (hibernation), the inotropic reserve was similar among the three categories, but in the other PET patterns the presence and extent of the inotropic reserve was higher in those regions with lowest Ecc (without significant differences in perfusion). In severe CAD, the presence of the inotropic reserve assessed by midmyocardial changes under dobutamine does not relate to resting perfusion. At a similar level of perfusion, the presence of the inotropic reserve is inversely related to contractile performance at rest, but our results suggest that it may not be true for hibernating myocardium.
在冠状动脉疾病（CAD）中，血流减少对心肌内收缩储备的影响尚未明确。因此，我们评估了在严重CAD患者中，低剂量多巴酚丁胺负荷下，正电子发射断层扫描（PET）灌注和葡萄糖摄取模式与心肌中层应变的相应标记磁共振成像（tagged MRI）值之间的关系。18例患者接受了标记MRI（静息状态、多巴酚丁胺负荷状态）及H2(15)O/18F-氟脱氧葡萄糖PET检查。在三个tagged MRI/PET短轴层面评估心肌中层圆周缩短（Ecc）及PET模式（正常、匹配存活、不匹配存活和梗死）。静息状态下局部心肌中层圆周缩短与灌注（r = 0.49）及葡萄糖摄取（r = 0.58）均相关。正常、匹配存活和梗死区域中收缩储备的存在情况相似（约40%的区域，不匹配存活区域为52%，P < 0.05），但梗死区域多巴酚丁胺负荷后增加的程度较低（P = 0.06）。在每种PET模式内，根据静息状态下的Ecc值将区域分为三类（高、中、低收缩功能）。在不匹配存活（冬眠）区域，三类区域的收缩储备相似，但在其他PET模式中，Ecc最低的区域收缩储备的存在情况及程度更高（灌注无显著差异）。在严重CAD中，通过多巴酚丁胺负荷下心肌中层变化评估的收缩储备的存在情况与静息灌注无关。在相似的灌注水平下，收缩储备的存在情况与静息收缩功能呈负相关，但我们的结果表明，对于冬眠心肌可能并非如此。
