Читать книгу Interventional Cardiology - Группа авторов - Страница 289

The available evidence suggests that PCI and CABG are equivalent for the treatment of single vessel disease. This was specifically investigated in the MASS trial at a single center in which patients with significant (>80%) proximal LAD stenosis were randomized to balloon angioplasty, CABG, or medical therapy. The data demonstrated that there was similar relief of symptoms with both forms of revascularization. However, revascularization resulted in a lower incidence of inducible ischemia compared to medical therapy alone, and all three strategies resulted in the effective treatment of limiting angina [17]. Similar findings have been reported from another small study of 134 patients with isolated proximal LAD stenosis in which angioplasty and CABG produced comparable results [26] also when the follow‐up is prolonged to 10 years [27]. Importantly, the need for repeat revascularization during follow‐up was greater with percutaneous revascularization using balloon angioplasty in both trials.

In the assessment of trials comparing surgery with PCI, an important premise is that none of these studies have specifically addressed the functional significance of the lesions treated. With respect to PCI in multivessel disease, the Fractional Flow Reserve vs Angiography for Multivessel Evaluation (FAME) trial demonstrated that a targeted strategy guided by measurement of FFR provides superior outcomes at one year compared with treatment of all vessels with visually estimated significant stenoses [28]. Several randomized clinical trials [29–34] and meta‐analyses of the data [35] have compared PCI directly with CABG for the treatment of single and multivessel disease. The studies, predominantly from the pre‐stent era, were among relatively low risk patients with multivessel disease and preserved LV function. By design, the inclusion criteria for these trials had mandated that the coronary anatomy was suitable for both forms of revascularization, thereby excluding most patients with very complex coronary anatomy or chronic total occlusions. These older trials provided important lessons, but are not directly relevant to current practice because they predated stents and the widespread use of internal mammary artery graft in CABG.

The largest of these studies is the Bypass Angioplasty Revasculari‐zation Investigation (BARI) trial in which 1829 patients were enrolled. PCI was performed with balloon angioplasty which was associated with similar frequency of death, myocardial infarction, and recurrent angina when compared with CABG during 10 years of follow‐up in the overall study population [36]. Not surprisingly, repeat revascularization was significantly less common in patients randomized to surgery. One notable finding that has influenced current practice is that cardiac mortality was significantly lower (19.4% vs 34.5%; p = 0.003) amongst diabetics requiring glucose lowering therapy who were randomized to CABG and received at least one mammary graft. Potential explanations for this observation are that CABG offers complete revascularization and hence mitigates some of the adverse impact of the greater atherosclerotic burden and “future culprit” lesions, as well as the greater likelihood of restenosis and disease progression in diabetic patients. This finding has been confirmed in a more recent study [37] but the clinical relevance and applicability of the BARI study results have been questioned by the findings from the BARI registry, which highlighted the importance of clinical judgment. The patients in the registry had clinical characteristics that were similar to those in the randomized trial, but the survival among diabetic patients was similar regardless of whether angioplasty or CABG was performed. It has been speculated that the conflicting results between the registry and the trial may have been because the treatment assignment in the registry was at the discretion of the physicians who might have selected the most appropriate form of revascularization for each patient [38].

The Arterial Reascularization Therapy Study Part I (ARTS I) and the Stent or Surgery (SoS) trials have compared bare metal stent based PCI with CABG [39,40]. In the ARTS I trial, death and myocardial infarction were similar with both treatment strategies, but, as one might expect, complete revascularization was less often achieved and repeat revascularization was more frequent with percutaneous revascularization. The results of the SoS trial were similar but, for reasons that are unclear, there was an unexpected higher mortality associated with PCI (5% vs 2%; p = 0.01), likely unrelated to treatment selection as the difference was entirely a result of non‐cardiac deaths. The long‐term results (5–6 years) of the ARTS, ERACI II, and SoS trials, and a large (7812 patients) meta‐analysis including 10 randomized trials of balloon angioplasty or stenting vs surgery with a median follow‐up of 5.9 years has been published [41–44]. In the meta‐analysis, long‐term mortality was similar after CABG and PCI in patients with multivessel CAD (hazard ratio 0.91, 95% CI 0.82–1.02; p = 0.12). CABG was associated with a significantly lower mortality in patients with diabetes (HR 0.70, 0.56–0.87; p = 0.014 for interaction) and patients aged 65 years or older (0.82, 95% CI 0.70–0.97; p = 0.002 for interaction).

DES account for vast majority of stents used for contemporary PCI around the world, but there are limited data comparing the outcomes between PCI using DES and CABG. There are three randomized clinical trials (SYNTAX, CARDia, and FREEDOM) to date [45–47]. The Synergy Between PCI with TAXUS and Cardiac Surgery (SYNTAX) trial randomized 1800 patients with three vessel and/or left main disease to either CABG or PCI after a local interventional cardiologist and cardiac surgeon at each site prospectively evaluated eligible patients and determined that equivalent anatomic revascularization could be achieved with either strategy [45]. A score of anatomic complexity (SYNTAX score: www.syntaxscore. com) was prospectively calculated. Unlike most previous trials where a small minority of patients who were screened were ultimately enrolled, almost half of the 4337 screened were randomized, with the majority of those excluded were unsuitable for PCI. The rates of death and myocardial infarction at 12 months were similar in the two groups. Stroke was significantly more frequent in the CABG group (2.2% vs 0.6%; p = 0.003) while the incidence of stent thrombosis and symptomatic graft occlusion at 12 months were similar in the two groups (3.3 and 3.4%, respectively). An increased rate of repeat revascularization in the PCI group (13.5% vs 5.9%; p < 0.001) led to an excess of major cardiac and cardiovascular events in the PCI group, with the endpoint of the trial (non‐inferiority of PCI using DES) not being met. Subgroup analysis based on the predetermined SYNTAX score showed that the negative outcome was confined to patients with high scores (>33, 10.9% in the surgical arm vs 23.4% in the PCI arm). The patients with left main disease had similar incidence of 12 month MACE in the surgical and PCI groups (13.7 vs 15.8%; p = 0.44). At 5‐year follow‐up, the composite primary endpoint (death from any cause, stroke, MI, or repeat revascularization) remained significantly higher (37.3% vs 26.9%) in the PCI group due primarily to the higher rates of repeat revascularization and myocardial infarction. The rates of all‐cause death and stroke were not different [48]. When analyzed by SYNTAX score, those with a score of <23, inclusive of left main patients, there was no difference in the composite primary endpoint (32.1% vs 28.6%; p = 0.43). In those with a SYNTAX score of 23–32 with unprotected left main disease, the outcomes were similar (32.7% vs 32.3%; p = 0.88); but not in patients with three vessel disease in whom PCI had higher event rates for the primary composite endpoint (37.9% vs 22.6%; p = 0.0008). For patients with a SYNTAX score ≥33, the rates were higher in patients with left main disease (46.5% vs 29.7%; p = 0.003) and those with three vessel disease without (41.9% vs 24.1%; p = 0.0005) unprotected left main disease. At 10 years follow‐up, CABG was associated with a survival benefit in patients with three‐vessel disease [49]. The results of the SYNTAX trial indicate that CABG remains the standard for patients with complex three vessel disease. However, in patients with less complex disease (i.e., left main coronary disease with low and possibly intermediate SYNTAX scores, or three vessel disease with low SYNTAX scores), PCI is a reasonable alternative treatment to CABG. In patients with a high SYNTAX score, the potential advantages of surgery should be stressed, but PCI should not be denied to patients who have a strong preference or a very high surgical risk. However, these conclusions must be interpreted in the context of the trial’s limitations, such as the use of a first generation (paclitaxel‐eluting) stent, which has a higher rate of restenosis than current second generation drug‐eluting stents. Also, the analyses of subgroups by SYNTAX score was not pre‐specified or adequately powered, and therefore the findings should be considered hypothesis generating.

In the Coronary Artery Revascularization in Diabetes (CARDia) trial, 510 diabetic patients with multivessel or complex single vessel coronary disease were randomized to PCI using a stent (and routine abciximab) or CABG. The trial was underpowered for the primary endpoint (composite of all‐cause mortality, myocardial infarction, and stroke), and at one year there was no difference between CABG and the 69% of patients who received a DES (12.4% and 11.6%; p = 0.82) [46]. In the Future Revascularization Evaluation in Patients with Diabetes Mellitus: Optimal Management of Multivessel Disease (FREEDOM) trial, 1900 patients with diabetes and multivessel (83% with three vessel) disease (median SYNTAX score of 26) were randomized to either PCI with a first generation (paclitaxel or sirolimus‐eluting) stent or CABG. Both groups received optimal medical therapy [47]. At a median follow‐up of 3.8 years, the primary composite endpoint death from any cause, non‐fatal myocardial infarction, or non‐fatal stroke was more frequent in the PCI group (26.6% vs 18.7%; p = 0.005). The benefit of CABG was predominantly because of lower rates of myocardial infarction and death from any cause while stroke was more frequent in the CABG group (2.4% vs 5.2%; p = 0.03 at 5 years). The findings of FREEDOM suggest that in patients with diabetes and advanced CAD, CABG is superior to PCI using first generation stents.