|Budget Amount *help
¥2,900,000 (Direct Cost : ¥2,900,000)
Fiscal Year 1998 : ¥1,300,000 (Direct Cost : ¥1,300,000)
Fiscal Year 1997 : ¥1,600,000 (Direct Cost : ¥1,600,000)
Transmyocardial laser revascularization (TMLR) enables myocardium to increase blood supply by creation of micropores. Although the clinical symptom of angina pectoris was improved by TMLR, the precise mechanism as well as long term results are unclear. The purpose of this study is to investigate chronic effects of TMLR on tissue blood flow (TBF) and destruction of neuroreceptors.
<Methods> Fourteen swine were used in this study. In all animals, 30 microchannels by TMLR were created around the left anterior descending artery and the first diagonal artery (D1). Then, D1 was ligated in group 1 (n=7), and was intact in group 2 (n=7). Twelve months after operation, D1 of group 2 animals was also ligated. Regional wall motion (RWM) and TBF was measured in both groups. Furthermore, Bradykinin was injected into the myocardium around TMLR area to evaluate response to sympathetic neuroreceptors, which were confirmed by immunohistochemistry. <Results> In group 1, RWM of TMLR area was severely reduced or akinetic in association with poor TBF, and histology revealed marked fibrosis. In group 2, RWM was also reduced, but was better than in group 1 with substantially restored TBF. The response to Bradykinin was maintained in group 2, while it was poor in group 1. Tyrosine hydroxylase was observed around epicardium in both groups. <Conclusion> TMLR increased TBF, but failed to improve RWM. Since neuroreceptors were not destroyed by TMLR, it was speculated that angina pectoris was predominantly relieved after TMLR due to improvement of TBF rather than destruction of neuroreceptors.
【結果】1群においては、D1領域の壁運動はsevere reducedかnoneであり、組織血流も認められず、急性冠動脈閉塞に対するTMLRは効果が認められなかった。また組織学的検討においても、同部は著明な繊維化が認められ、Bradykininによる痛み刺激に対しても反応が著しく低下していた。2群においては、D1を結紮した後、同部の壁運動は低下しているものの、組織血流と共に同部の心筋の梗塞部位縮小効果が認められた。またTyrosine Hydroxylase染色においては1群、2群、正常対照群とも心筋外膜周囲の結合組織中に十分存在した。【結論】TMLRは虚血に対してある程度の血流改善効果をもたらしたが,その効果は壁運動を改善させるまでには至らなかった。また,TMLRによっては交感神経末端は破壊されず,胸心痛の消失は組織血流の改善によるものと考えられた。