Wilson J M, Ferguson J J
Texas Heart Institute, Houston 77030, USA.
Tex Heart Inst J. 1995;22(2):145-61.
Coronary artery bypass surgery relieves the symptoms of myocardial ischemia and prolongs survival of patients with more severe coronary artery disease. Randomized trials of surgical therapy have consistently shown that the benefits of surgical revascularization are proportional to the amount of myocardium affected by, or at risk for, ischemic injury. This risk is inferred from angiographically delineated coronary anatomy, estimates of left ventricular function, and physiologic testing. The population that may see a survival benefit from surgical revascularization has probably been expanded beyond that reported in the VA, CASS, and ECSS trials, due to improved perioperative care, longer graft survival, and the use of internal mammary artery grafts. Percutaneous transluminal coronary angioplasty revascularizes myocardium by dilating a stenotic segment of coronary artery. While successful in relieving the symptoms of myocardial ischemia, PTCA is hindered by the occurrence of abrupt vessel closure and the frequent development of restenosis. Furthermore, firm proof of a survival benefit, outside of emergency therapy for acute myocardial infarction, is not yet available. However, because the risk of procedure-related death or serious complication is lower than that seen with bypass surgery, PTCA provides a useful alternative revascularization method for patients with less extensive disease, in whom the risk of surgery may equal or exceed any beneficial effect. New technology and growing experience are widening the scope of percutaneous revascularization by extending the hope of symptomatic relief and survival benefit even to patients with extensive, severe coronary artery disease. Comparisons between surgical therapy and PTCA in select populations with single- and multivessel coronary artery disease have shown that PTCA is not as effective as surgery for long-term symptomatic control, and that it often requires repeat PTCA or cross-over to bypass surgery; however, long-term outcomes (i.e., death and myocardial infarction) are similar. The cost of treatment beginning with PTCA may be lower than that of initial surgery, even when the increased need for repeat revascularization is taken into account. Despite this, surgical bypass remains the mainstay of therapy for patients with severe coronary artery disease and a poor prognosis for survival, and will remain the fallback procedure for patients who repeatedly undergo failed PTCA. At the present time, revascularization should be offered on the basis of symptom severity (in the presence of medical therapy) and in accordance with the prognosis for survival as judged by the extent and severity of disease (Table VI). Percutaneous transluminal coronary angioplasty is preferred in patients who require revascularization but can obtain no proven benefit from bypass surgery. Coronary artery bypass surgery, using the internal mammary artery when possible, remains the revascularization method of choice for patients with more severe disease or whose disease is not amenable to treatment using percutaneous methods (Table VII).
冠状动脉搭桥手术可缓解心肌缺血症状，并延长冠心病病情较重患者的生存期。外科治疗的随机试验一直表明，外科血管重建术的益处与受缺血性损伤影响或有缺血性损伤风险的心肌量成正比。这种风险可通过血管造影显示的冠状动脉解剖结构、左心室功能评估和生理测试推断出来。由于围手术期护理的改善、移植血管更长的生存期以及胸廓内动脉移植血管的使用，可能从外科血管重建术中获得生存益处的人群范围可能已超出退伍军人事务部（VA）、冠状动脉外科研究（CASS）和欧洲冠状动脉外科研究（ECSS）试验报告的范围。经皮冠状动脉腔内血管成形术通过扩张冠状动脉的狭窄段使心肌血管重建。虽然经皮冠状动脉腔内血管成形术成功缓解了心肌缺血症状，但它受到血管突然闭塞和再狭窄频繁发生的阻碍。此外，除了急性心肌梗死的紧急治疗外，尚无确凿证据表明其具有生存益处。然而，由于与手术相关的死亡或严重并发症风险低于冠状动脉搭桥手术，经皮冠状动脉腔内血管成形术为病情不太广泛、手术风险可能等于或超过任何有益效果的患者提供了一种有用的替代血管重建方法。新技术和经验的积累正在扩大经皮血管重建的范围，甚至为患有广泛、严重冠状动脉疾病的患者带来缓解症状和生存益处的希望。对单支和多支冠状动脉疾病特定人群的外科治疗与经皮冠状动脉腔内血管成形术的比较表明，经皮冠状动脉腔内血管成形术在长期症状控制方面不如手术有效，并且通常需要重复进行经皮冠状动脉腔内血管成形术或转而进行搭桥手术；然而，长期结局（即死亡和心肌梗死）相似。即使考虑到重复血管重建需求的增加，从经皮冠状动脉腔内血管成形术开始的治疗费用可能低于初次手术。尽管如此，冠状动脉搭桥手术仍然是严重冠状动脉疾病且生存预后不良患者的主要治疗方法，并且对于反复接受经皮冠状动脉腔内血管成形术失败的患者仍将是备用手术。目前，血管重建应根据症状严重程度（在有药物治疗的情况下）以及根据疾病的范围和严重程度判断的生存预后进行（表六）。对于需要血管重建但无法从搭桥手术中获得已证实益处的患者，首选经皮冠状动脉腔内血管成形术。对于病情更严重或其疾病不适合采用经皮方法治疗的患者，尽可能使用胸廓内动脉的冠状动脉搭桥手术仍然是血管重建的首选方法（表七）。
