Hamawy A H, Lee L Y, Samy S A, Polce D R, Szulc M, Vazquez M, Rosengart T K
Weill Medical College of Cornell University, New York, New York, USA.
Ann Thorac Surg. 2001 Sep;72(3):817-22. doi: 10.1016/s0003-4975(01)02837-5.
Transmyocardial laser revascularization (TMR) appears to provide symptomatic relief to patients with ischemic heart disease, but evidence that TMR enhances perfusion to ischemic myocardium remains limited. Furthermore, it is uncertain whether there exists a TMR dose-response relationship that is a function of channel number. We therefore compared restoration of blood flow as analyzed by rest and stress 99mTc-sestamibi scans and histologic grading of neovascularization after 50-channel, 25-channel, or 10-channel TMR using the excimer laser in an established model of porcine myocardial ischemia.
Yorkshire swine underwent a thoracotomy and placement of an ameroid constrictor around the proximal circumflex coronary artery. Three weeks later, the animals underwent resting and adenosine stress 99mTc-sestamibi scans for evaluation of ischemia immediately before repeat thoracotomy and TMR with either 50 channels (n = 4), 25 channels (n = 4), or 10 channels (n = 4) in the circumflex territory. The animals underwent repeat perfusion analyses 4 weeks later, after which the animals were sacrificed and the hearts were perfusion fixed for histologic evaluation of neovascularization.
All animals survived to sacrifice. Semiquantitative analyses of the sestamibi perfusion scans 4 weeks after lasing demonstrated significant improvement (p < 0.04) in stress-induced ischemia in the 50-channel TMR animals, but not in the 25- or 10-channel TMR groups, as compared with scans obtained immediately before lasing. A computerized image analysis of perfusion scans similarly demonstrated an improvement in the area of ischemia of 42% +/- 22% in the scans obtained 4 weeks after lasing compared with scans obtained immediately before lasing in the 50-channel group (p < 0.004), but only a 12% +/- 9% improvement in the 25-channel group and an 8% +/- 4% improvement in the 10-channel group (p > 0.05). Histologic assessment of neovascularization demonstrated significantly greater number of microvessels per low-power field in the 50- versus the 25- and 10-channel groups (p < 0.001).
In an animal model of myocardial ischemia, TMR appears to enhance myocardial perfusion. A dose-response relationship related to channel number may be of significance when evaluating the efficacy of various treatment strategies.
经心肌激光血运重建术（TMR）似乎能缓解缺血性心脏病患者的症状，但TMR增强缺血心肌灌注的证据仍然有限。此外，尚不确定是否存在与通道数量相关的TMR剂量反应关系。因此，我们在已建立的猪心肌缺血模型中，比较了使用准分子激光进行50通道、25通道或10通道TMR后，通过静息和负荷99mTc-甲氧基异丁基异腈扫描分析的血流恢复情况以及新生血管形成的组织学分级。
约克郡猪接受开胸手术，并在左旋冠状动脉近端放置阿梅里德缩窄环。三周后，在重复开胸手术和左旋支区域进行50通道（n = 4）、25通道（n = 4）或10通道（n = 4）TMR之前，对动物进行静息和腺苷负荷99mTc-甲氧基异丁基异腈扫描以评估缺血情况。四周后对动物进行重复灌注分析，之后处死动物并对心脏进行灌注固定以进行新生血管形成的组织学评估。
所有动物均存活至处死。激光治疗四周后对甲氧基异丁基异腈灌注扫描的半定量分析显示，与激光治疗前立即进行的扫描相比，50通道TMR组动物的负荷诱导缺血有显著改善（p < 0.04），而25通道或10通道TMR组则无改善。灌注扫描的计算机图像分析同样显示，与50通道组激光治疗前立即进行的扫描相比，激光治疗四周后的扫描中缺血面积改善了42%±22%（p < 0.004），但25通道组仅改善了12%±9%，10通道组改善了8%±4%（p > 0.05）。新生血管形成的组织学评估显示，50通道组与25通道组和10通道组相比，每个低倍视野中的微血管数量显著更多（p < 0.001）。
在心肌缺血动物模型中，TMR似乎能增强心肌灌注。在评估各种治疗策略的疗效时，与通道数量相关的剂量反应关系可能具有重要意义。
