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.
Recommendations for revascularization in stable angina
Broadly speaking, revascularization is appropriate for patients with limiting symptoms despite optimal medical therapy, as well as those with strongly positive stress tests, proximal multivessel disease, and active patients who prefer an interventional approach over medical therapy. The choice between PCI and CABG in any one patient is determined by extent of disease, the risks of the procedure, likelihood of success, and ability to achieve complete revascularization with the two strategies as well as diabetic status and patient preference. While medical therapy is the cornerstone of treatment of stable angina, it is important to remember that there is no evidence that medical therapy alone improves prognosis in high risk patients, as defined in the clinical trials of medical treatment vs CABG.
Patients with significant proximal LAD artery disease have a survival advantage with CABG over medical therapy, even in the absence of severe symptoms, LV dysfunction, or other lesions. PCI provides similar results among patients who have suitable anatomy for PCI of the proximal LAD and normal LV function (Tables 11.2 and 11.3).
CABG offers a survival advantage over medical therapy in patients with severe symptoms and three vessel disease, even in the absence of proximal LAD involvement or LV dysfunction. Patients with three vessel disease and LV dysfunction should have CABG. PCI is an alternative to CABG for three vessel disease in those with angiographically suitable targets and normal LV function (e.g., SYNTAX score ≤22; Tables 11.2 and 11.3). Surgical revascularization is recommended for significant left main disease though PCI is an alternative in patients with SYNTAX score of ≤22, and may be considered for those with a SYNTAX score of 23–32 (Tables 11.2 and 11.3).
In patients with diabetes mellitus, in the setting of multivessel or diffuse disease, there is a survival advantage with CABG over PCI. PCI is reasonable for diabetics with discrete two vessel disease (e.g., SYNTAX score ≤22) and preserved LV function.
For the majority of patients with stable CAD who do not fall into the subgroups described, there is no documented survival advantage with revascularization. PCI and CABG should be offered for the treatment of symptoms refractory to medical therapy. The guidelines state that both forms of revascularization are suitable for two vessel disease, but in current practice the majority of these patients and those with single vessel disease are treated with PCI unless the lesions are angiographically unsuitable, or involve the proximal LAD [57].
Revascularization in asymptomatic patients should only be considered with the goal of improving prognosis. The guidelines for the treatment of asymptomatic patients are similar to those for symptomatic patients. However, the level of evidence for asymptomatic patients is weaker as the clinical trials have mainly included symptomatic patients. The presence and extent of inducible ischemia are important considerarions for guiding management in asymptomatic patients.
Conclusions
Unlike PCI for acute coronary syndromes, percutaneous revascularization does not prevent death or myocardial infarction in patients with stable angina. There remains the possibility that PCI can reduce these endpoints in high risk patients, but clinical trials in such patient subsets have not been conducted. For patients with lower risk, the main advantage of PCI is the ability to effectively and more rapidly relieve symptoms. In general, therefore, PCI is indicated for the treatment of symptomatic coronary atherosclerosis, particularly in patients who remain symptom limited despite optimal medical therapy. PCI is the preferred revascularization strategy for single vessel disease, younger patients (age <50 years), elderly patients with significant comorbid conditions, and those who are not surgical candidates. There is no clear indication for PCI in the treatment of asymptomatic disease.
CABG is also highly effective in relieving symptoms, but importantly it reduces mortality in high risk patients. This benefit is proportional to baseline risk profile of the patient. Complete revascularization is more likely to be achieved with CABG. Thus, CABG is preferred for high risk patients such as those with multivessel disease where complete revascularization is an important goal, particularly in three vessel disease, and in the presence of significant LV systolic dysfunction. Subgroups that should be considered for surgery include significant unprotected left main disease, three vessel disease, especially if there is impaired LV function, diffuse atherosclerosis, or one or more chronic total occlusion. An important group of patients who benefit with CABG are diabetics with three vessel disease. However, as with PCI, CABG does not reduce the incidence of non‐fatal myocardial infarction. PCI for multivessel disease, even with the use of first generation DES, is associated with higher rates of repeat revascularization than CABG.
Ongoing advances in medical therapy for secondary prevention, PCI and CABG result in limited data being available from clinical trials that reflect contemporary practice, especially in high risk patients. The FAME 3 trial (ClinicalTrials.gov Identifier: NCT02100722) will provide much needed data regarding the comparative efficacy of physiology guided PCI using second generation stents compared to CABG.
Interactive multiple choice questions are available for this chapter on www.wiley.com/go/dangas/cardiology
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