低心機能の単独冠状動脈バイパス手術成績と左室拡張期末期径係数の関係

Influence of Left Ventricular End-diastolic Diameter Index on Surgical Outcomes After Isolated Coronary Artery Bypass Grafting in Patients with Left Ventricular Ejection Fraction ≦35％

低左室駆出率（left ventricular ejection fraction：LVEF）は冠状動脈バイパス術（CABG）や弁膜症手術において，早期および遠隔期死亡率の上昇に大きく関与する1～3）．CABGを施行したLVEF 30％未満群では，LVEF正常群と比べて術後死亡率と遠隔期生存率が有意に不良であった2）．これらの研究では，LVEFのみに焦点を当て術後成績が議論されている．その後，開心術を受けた低LVEF患者を対象として，左室容量が拡大した群では拡大していない群に比し術後成績が不良である報告が散見された4～6）．

We examined the influence of left ventricular diameter on surgical outcomes after isolated coronary artery bypass grafting （CABG） in patients with left ventricular ejection fraction （LVEF） ＜35％. The subjects were patients who underwent isolated CABG with and without cardiopulmonary bypass from January 2015 to the end of August 2023. Twenty-four patients were categorized into the LVEF ≧55％ group （group N） and 14 patients into the LVEF ≦35％ group （group L）. Ten patients in group L were categorized into the group L-1 ［moderately or more enlarged LV according to the left ventricular end-diastolic diameter （LVEDD） index （LVEDD/body surface area）］. Primary endpoints were all-cause mortality, major complications, and postoperative hospitalization rate of more than 14 days. Complication rates were not statistically different between group N and L. The results were similar between group N and L-1. However, the group L had a significantly higher rate of hospitalization for 14 days or more after surgery compared with that in the group N （p＝0.007）. Similarly, the rate of hospitalization for more than 14 days was significantly higher in the group L-1 than that in the group N （p＝0.029）. In patients with LVEF ≦35％ undergoing isolated CABG, postoperative outcomes were similar to those with LVEF ≧55％, regardless of LV enlargement.