Haas F, Jennen L, Heinzmann U, Augustin N, Wottke M, Schwaiger M, Lange R
Department of Cardiovascular Surgery, Deutsches Herzzentrum Muenchen, Munich, Germany.
Eur J Cardiothorac Surg. 2001 Aug;20(2):290-8. doi: 10.1016/s1010-7940(01)00781-3.
It has been demonstrated that positron emission tomography (PET) predicts the functional recovery of viable but ischemically compromised myocardium. Reversible contractile dysfunction after revascularization has been reported for 'hibernating myocardium' and stunned myocardium, however, there are little data concerning the time-course and the extent of improvement of the two different pathophysiological conditions.
Twenty-nine patients with advanced coronary artery disease and severely reduced left ventricular function (EF 18--35%) who were referred for isolated coronary artery bypass grafting underwent preoperative PET viability assessment and were functionally assessed by two-dimensional echocardiography preoperatively at 11 days, 14 weeks, and more than 12 months after surgical revascularization. Intraoperative biopsies were taken from dysfunctional areas defined by PET as segments of normal perfusion and normal metabolism (stunned myocardium) and from areas with a 'mismatch' between perfusion and metabolism (hibernating myocardium). The degree of morphological alterations was evaluated by electron microscopy.
In 70% of the 240 dysfunctional segments, 'stunned myocardium' was present whereas 'hibernating myocardium' could be detected in only 24% (P < 0.01). Hibernating myocardium was associated with more severe preoperative wall motion abnormalities and incomplete postoperative recovery. After 1 year, 31% of 'stunned' segments vs. only 18% of 'hibernating' segments showed complete functional restoration (P < 0.05). This incomplete improvement was associated with more severe morphological alterations including depletion of sarcomeres, accumulation of glycogen, loss of sarcoplasmatic reticulum, and cellular sequestration.
These data indicate that in patients with severe ischemic left ventricular dysfunction 'stunned myocardium' is more prevalent than 'hibernation'. Functional normalization is more frequent in 'stunned' segments, whereas areas of 'hibernation' showed more severe tissue injury and protracted recovery. Different degrees of myocardial injury coexist in most patients, which determines the time-course and the extent of improvement after revascularization.
正电子发射断层扫描（PET）已被证实可预测存活但因缺血而受损心肌的功能恢复情况。“冬眠心肌”和顿抑心肌在血运重建后出现可逆性收缩功能障碍已有报道，然而，关于这两种不同病理生理状态改善的时间进程和程度的数据却很少。
29例晚期冠状动脉疾病且左心室功能严重降低（射血分数18% - 35%）、拟行单纯冠状动脉旁路移植术的患者接受了术前PET存活评估，并在手术血运重建后11天、14周和12个月以上通过二维超声心动图进行术前功能评估。术中从PET定义为正常灌注和正常代谢节段（顿抑心肌）的功能障碍区域以及灌注与代谢“不匹配”区域（冬眠心肌）取活检组织。通过电子显微镜评估形态学改变的程度。
在240个功能障碍节段中，70%存在“顿抑心肌”，而仅24%可检测到“冬眠心肌”（P < 0.01）。冬眠心肌与术前更严重的室壁运动异常及术后不完全恢复相关。1年后，31%的“顿抑”节段与仅18%的“冬眠”节段显示完全功能恢复（P < 0.05）。这种不完全改善与更严重的形态学改变相关，包括肌节减少、糖原积聚、肌浆网丢失和细胞隔离。
这些数据表明，在严重缺血性左心室功能障碍患者中，“顿抑心肌”比“冬眠心肌”更普遍。“顿抑”节段功能正常化更常见，而“冬眠”区域显示更严重的组织损伤和恢复延迟。大多数患者存在不同程度的心肌损伤并存，这决定了血运重建后改善的时间进程和程度。
