Читать книгу Interventional Cardiology - Группа авторов - Страница 290

The European Coronary Surgery Study (ECSS), Coronary Artery Surgery Study (CASS), and Veterans Administration Cooperative Study (VA Study) are relatively small, randomized trials that have compared CABG with medical therapy among patients with mild to moderate angina [50–52]. They were conduced over 35 years ago in an era when there was no effective medical therapy for CAD. The consistent finding from these studies was that surgical revascularization provides better symptomatic relief from angina, but the benefit is lost over time, most likely because of vein graft failure and subsequent crossover to CABG in the medical treatment arm. The randomized trials and a meta‐analysis [53] indicate that an initial strategy of surgical revascularization does not improve survival in the general population of CAD, but that there are specific subsets that either have a large amount of ischemic myocardium or significant LV dysfunction. Thus, patients with three vessel disease (especially in those with abnormal LV function), two or three vessels disease with >75% stenosis of the LAD or a markedly positive stress test derive prognostic benefit from CABG. In general, patients with severe symptoms have been excluded from the trials, but an analysis from registry data of the CASS study indicates that surgical revascularization probably improves prognosis in patients with severe angina who have multivessel disease, even in the absence of LV dysfunction or proximal LAD stenosis [54]. It is important to be aware that this evidence, which has been used to craft current guidelines, is limited by the fact that the randomized trials were all conducted in the early years of bypass surgery, and are not representative of the contemporary surgical techniques such as the routine use of internal mammary grafts or minimally invasive and off‐pump surgery. Conversely, the medical group did not benefit from the aggressive preventive measures which are now routine nor did they consistently receive beta‐blockers or angiotensin‐converting enzyme (ACE) inhibitors. Furthermore, the general applicability of these trials is limited by the fact that they did not enrol many women or patients over 65 years old.

The STICH trial has reported outcomes in stable multivessel CAD (excluding significant left main or CCS III/IV angina) in the presence of reduced left ventricular function (EF≤35%). The intial data showed no benefit of CABG compared to medical therapy alone, but in the 10‐year follow‐up (STICHES) analysis, cardiovascular and all‐cause mortality was lower with CABG [55,56]. In a substudy of the STICH trial, detection of myocardial viability using SPECT perfusion imaging or dobutamine echocardiography did not identify patients who would benefit from CABG surgery. There are no randomized trials comparing PCI with CABG in this patient subset, and hence current evidence supports CABG over PCI.