冠動脈側副血行の急性心筋梗塞へ与える効果

Effects of coronary collateral circulation in evolving myocardial infarction:as a major determinant of preserving myocardial function after intracoronary thrombolysis

　近年，急性心筋梗塞に対して，その梗塞量を減少させる目的で，ウロキナーゼやストレプトキナーゼのような血栓溶解物質を冠動脈内に直接注入し，閉塞血管を再開通させることが可能となり^1,2），その左室機能に及ぼす効果が議論されている^3〜12）。しかし，心筋梗塞が発症してから冠動脈内血栓溶解療法（以下PTCR）により血行が再開通するまでの期間に，側副血行が心筋壊死に陥るのを遅延することができるかどうかについては，まだ十分には検討されていない。そこで，我々は，今回発症後8時間以内の急性心筋梗塞で，緊急冠動脈造影及びPTCRを試みた症例を，側副血行の発達状態によりサブグループに分類し，急性期及び慢性期の左心室の局所壁運動を比較して，側副血行及びPTCRの左心機能に与える効果を評価した。

The effects of coronary collateral circulation were assessed in 26 patients with acute myocardial infarction, who underwent intracoronary thrombo-lytic therapy within 8 hours after the onset of symptoms. These patients were divided into four groups based on the development of collateral circulation in the acute phase and the results of intracoronary thrombolytic therapy. Group A con-sisted of 10 patients who had well-developed col-lateral circulation and successful thrombolysis with sustained patency. Group B consisted of 5 patients who had less-developed or no collateral circulation and successful thrombolysis with sustained patency. Group C consisted of 5 patients who had well-developed collateral circulation and unsuccessful thrombolysis. Group D consisted of 6 patient who had less-developed or no collateral circulation and unsuccessful thrombolysis. Patients in group A had a significant increase in regional wall shortening from the acute phase to the late phase (from 4.4±8.8% to 30.0±9.4%; p<0.001), whereas patients in other groups did not. In the repeat left ventriculo-graphy, patients in group A had much higher regional wall shortening compared with patients in group B, C, and D (A vs. B, 30.0±9.4% vs.9.9±7.8%; p<0.01: A vs. C or D, 30.0±9.4% vs. 2.0±2.8% or 2.4±7.6% ; p<0.001). More-over, there was no significant difference in regional wall shortening among patients in group B, C, and D. This study indicates that well-developed collateral circulation can prolong the time course of myocardial cell death, therefore only patients with well-developed collateral circulation can be expected to improve in regional wall shortening by means of intracoronary thrombolytic therapy.