Cardiovascular Unit, Campo di Marte Hospital, Lucca, Italy.
Eur Heart J Cardiovasc Imaging. 2012 Mar;13(3):219-26. doi: 10.1093/ejechocard/jer237. Epub 2011 Nov 11.
Stunning and hibernation represent two different forms of tissue viability identifiable in acute coronary syndromes and chronic ischaemic cardiomyopathy, respectively. Functional recovery occurs spontaneously with myocardial stunning, while it generally follows revascularization in case of hibernating myocardium. Low-dose dobutamine stress echocardiography is an accurate modality for identifying myocardial stunning and provides important information on ventricular remodelling after both systemic thrombolysis and primary angioplasty. In patients with conservatively treated infarction, the prognostic significance of viability by dobutamine stress echocardiography correlates with residual pump function. Substantial contractile reserve is predictive of favourable outcome in patients with poor but not in those with preserved or slightly reduced left ventricular function. Non-invasive assessment of coronary flow reserve with transthoracic Doppler echocardiography of the left anterior descending coronary artery allows to distinguish between necrotic and stunned myocardium and predicts ventricular remodelling following primary angioplasty. Resting echocardiographic examination can provide information on hibernating myocardium. In particular, systolic thickening <7 mm, restrictive filling pattern, and high end-systolic volume are predictive of no viability. Compared with nuclear imaging, dobutamine stress echocardiography is more specific for predicting functional recovery, less expensive, more generally available and radiation-free. A large body of evidence collected over the years demonstrates the favourable prognostic impact of revascularizing extensive myocardial territories which are found viable at dobutamine stress echocardiography in patients with ischaemic cardiomyopathy. The prognostic implications of viability-guided revascularization have been clearly established in both diabetic and non-diabetic patients. However, the prognostic value of myocardial viability has been questioned by the results of the STICH trial that did not demonstrate any advantage of survival in the patients with a large extent of myocardial viability undergoing revascularization. Is the end of a paradigm that deeply influenced clinical practice so far or just a neutral result that can be ignored due to the several limitations of study design? In the present review, we will address the main advantages and limitations of ultrasounds for the evaluation of myocardial viability and try to demonstrate that viability is still viable.
顿抑和冬眠分别代表了在急性冠脉综合征和慢性缺血性心肌病中可识别的两种不同的组织存活形式。心肌顿抑会自发地出现功能恢复，而冬眠心肌通常在血运重建后才会出现。小剂量多巴酚丁胺超声心动图是识别心肌顿抑的一种准确方式，并且能为溶栓和直接经皮冠状动脉介入治疗后心室重构提供重要信息。在保守治疗的梗死患者中，多巴酚丁胺超声心动图评估的存活能力与残余泵功能相关。在左心室功能较差、保存或轻度降低的患者中，有明显收缩储备预示着良好的预后，但在左心室功能保存或轻度降低的患者中则不然。经胸超声心动图左前降支冠状动脉多普勒血流储备评估可区分坏死心肌和顿抑心肌，并预测直接经皮冠状动脉介入治疗后的心室重构。静息超声心动图检查可提供冬眠心肌的信息。特别是，收缩期厚度＜7mm、限制型充盈模式和高收缩末期容积预测无存活能力。与核成像相比，多巴酚丁胺超声心动图对预测功能恢复更具特异性，更便宜，更普遍可用，且无辐射。多年来积累的大量证据表明，在缺血性心肌病患者中，通过多巴酚丁胺超声心动图发现广泛存活的心肌区域进行血运重建具有良好的预后影响。在糖尿病和非糖尿病患者中，存活心肌指导血运重建的预后意义已得到明确确立。然而，STICH 试验的结果质疑了心肌存活的预后价值，该试验并未显示在接受血运重建的具有大面积存活心肌的患者中生存有任何优势。这是否是一个迄今为止深刻影响临床实践的范例的终结，还是一个由于研究设计的几个局限性而可以忽略的中性结果？在本综述中，我们将讨论超声心动图评估心肌存活的主要优点和局限性，并试图证明存活心肌仍然具有重要意义。
