Ragosta M, Beller G A, Watson D D, Kaul S, Gimple L W
Department of Medicine, University of Virginia Health Sciences Center, Charlottesville.
Circulation. 1993 May;87(5):1630-41. doi: 10.1161/01.cir.87.5.1630.
Although many patients with multivessel coronary artery disease (CAD) and severely depressed left ventricular (LV) function will benefit from coronary artery bypass graft surgery (CABG), surgeons may be reluctant to perform CABG on these patients without evidence of myocardial viability in regions of severe asynergy. We hypothesized that quantitative planar rest-redistribution 201Tl imaging would identify viable myocardium and predict improved regional and global function after revascularization in patients with depressed LV function and CAD.
Twenty-one patients (mean LV ejection fraction, 0.27 +/- 0.05) were studied. Regional and global LV functions were evaluated before and 8 weeks after CABG with radionuclide ventriculography. Segments were prospectively classified as showing normal, mildly reduced, or severely reduced viability on the basis of quantitative analysis of defect severity and redistribution on planar resting 201Tl imaging. By 201Tl criteria, 90% of hypokinetic segments were classified with normal or mildly reduced viability. Among akinetic or dyskinetic segments, 20% had normal 201Tl uptake, 53% had mildly reduced viability, and only 27% had severely reduced viability. 201Tl viability criteria identified segments that improved function after CABG. Sixty-two percent of severely asynergic segments with normal viability and 54% with mildly reduced viability improved function after surgery, but only 23% with severely reduced viability improved function (p = 0.002). When only adequately revascularized segments were considered, the predictive value of a positive preoperative viability scan for functional improvement was 73%. The greatest improvement in global LV function after CABG occurred in patients with the greatest number of asynergic segments classified as viable before surgery (p < 0.01). In 10 patients with more than seven viable, asynergic segments, mean LV ejection fraction increased significantly after CABG (0.29 +/- 0.07 to 0.41 +/- 0.11, p = 0.002). In 11 patients with seven or fewer viable, asynergic segments, mean LV ejection fraction remained unchanged after revascularization (0.27 +/- 0.05 to 0.30 +/- 0.08, p = NS).
In patients with CAD and severely depressed LV function, preoperative quantitative planar rest-redistribution. 201Tl imaging identifies viability in many asynergic myocardial segments, and these segments frequently improve function after CABG. The presence of numerous asynergic but viable myocardial segments before surgery correlated significantly with improvement in global LV function after bypass surgery.
尽管许多患有多支冠状动脉疾病（CAD）且左心室（LV）功能严重受损的患者将从冠状动脉搭桥手术（CABG）中获益，但在严重运动失调区域若无心肌存活证据，外科医生可能不愿对这些患者实施CABG。我们推测，定量平面静息-再分布201Tl显像可识别存活心肌，并预测LV功能受损和CAD患者血运重建后局部和整体功能的改善情况。
对21例患者（平均LV射血分数为0.27±0.05）进行了研究。在CABG术前和术后8周，采用放射性核素心室造影评估LV局部和整体功能。根据平面静息201Tl显像上缺损严重程度和再分布的定量分析，将节段前瞻性地分类为显示正常、轻度减低或严重减低的存活情况。根据201Tl标准，90%的运动减弱节段被分类为存活正常或轻度减低。在运动不能或运动障碍节段中，20%的节段201Tl摄取正常，53%节段存活轻度减低，只有27%节段存活严重减低。201Tl存活标准可识别CABG术后功能改善的节段。存活正常的严重运动失调节段中62%和存活轻度减低的节段中54%术后功能改善，但存活严重减低的节段中只有23%功能改善（p = 0.002）。当仅考虑血运重建充分的节段时，术前存活显像阳性对功能改善的预测价值为73%。CABG术后LV整体功能改善最大的患者是术前分类为存活的运动失调节段数量最多的患者（p < 0.01）。在10例有7个以上存活的运动失调节段的患者中，CABG术后平均LV射血分数显著增加（从0.29±0.07增至0.41±0.11，p = 0.002）。在11例有7个或更少存活的运动失调节段的患者中，血运重建后平均LV射血分数保持不变（从0.27±0.05增至0.30±0.08，p =无显著性差异）。
在CAD和LV功能严重受损的患者中，术前定量平面静息-再分布201Tl显像可识别许多运动失调心肌节段的存活情况，这些节段在CABG术后功能常得到改善。术前存在大量运动失调但存活的心肌节段与搭桥术后LV整体功能改善显著相关。
