Class of recommendation.
b Level of evidence.
c PCI should be considered if the Heart Team is concerned about the surgical risk or if the patient refuses CABG after adequate counselling by the Heart Team.
d For example, absence of previous cardiac surgery, severe morbidities, frailty, or immobility precluding CABG.
Indications for coronary angiography
The decision regarding whether to treat a patient with medical therapy or revascularization is based on the fundamental principal of risk stratification. The spectrum of risk for myocardial infarction and cardiovascular death is wide even in stable CAD. Initial risk stratification and thereby the decision to perform coronary angiography can be determined by a combination of clinical evaluation, and in most cases stress testing and an assessment of left LV function (Figure 11.2). Those with high risk features on clinical evaluation such as severe angina, unstable angina, and severe heart failure should proceed directly to coronary angiography without being subjected to a stress test. Invasive coronary angiography is not indicated in low risk patients, however coronary CTA may be useful if imaging is desirable (Figure 11.3). The decision to perform non‐invasive testing in intermediate risk patients should be based on severity of symptoms, response to initial medical therapy, functional status, lifestyle, and occupation. Moreover, a detailed discussion with the patient regarding the risks, benefits, alternatives, and goals of invasive assessment is required prior to proceeding with coronary angiography. Coronary angiography is indicated in patients with high risk features on non‐invasive assessment irrespective of symptoms, severe angina (Class 3 of Canadian Cardiovascular Society Classification; CCS), limiting angina despite optimal medical therapy, diagnostic uncertainty after non‐invasive evaluation, and patients with the possibility of restenosis following PCI in a coronary distribution supplying a moderate to large amount of myocardium.
Figure 11.2 Approach for the initial diagnostic management of patients with angina and suspected coronary artery disease. ACS, acute coronary syndrome; BP, blood pressure; CAD, coronary artery disease; CTA, computed tomography angiography; ECG, electrocardiogram; FFR, fractional flow reserve; iFR, instantaneous wave‐free ratio; LVEF, left ventricular ejection fraction. aIf the diagnosis of CAD is uncertain, establishing a diagnosis using non‐invasive functional imaging for myocardial ischaemia before treatment may be reasonable. bMay be omitted in very young and healthy patients with a high suspicion of an extracardiac cause of chest pain, and in multimorbid patients in whom the echocardiography result has no consequence for further patient management. cConsider exercise ECG to assess symptoms, arrhythmias, exercise tolerance, BP response, and event risk in selected patients. dAbility to exercise, individual test‐related risks, and likelihood of obtaining diagnostic test result. eHigh clinical likelihood and symptoms inadequately responding to medical treatment, high event risk based on clinical evaluation (such as ST‐segment depression, combined with symptoms at a low workload or systolic dysfunction indicating CAD), or uncertain diagnosis on non‐invasive testing. fFunctional imaging for myocardial ischaemia if coronary CTA has shown CAD of uncertain grade or is non‐diagnostic. gConsider also angina without obstructive disease in the epicardial coronary arteries.
Source: Knuuti et al 2020 [4]. Reproduced by permission of Oxford University Press.
Figure 11.3 Main diagnostic pathways in symptomatic patients with suspected obstructive CAD. Depending on clinical conditions and the healthcare environment, patient workup can start with either of three options: non‐invasive testing, coronary CTA, or invasive coronary angiography. Through each pathway, both functional and anatomical information is gathered to inform an appropriate diagnostic and therapeutic strategy. Risk‐factor modification should be considered in all patients. CAD, coronary artery disease; CTA, computed tomography angiography; ECG, electrocardiogram; LV, left ventricular. aConsider microvascular angina. bAntianginal medications and/or risk‐factor modification.
Source: Knuuti et al. 2020 [4]. Reproduced by permission of Oxford University Press.
Percutaneous coronary intervention for stable angina
Several randomized trials have compared the outcomes following PCI with medical management for stable angina [8–11]. These include the studies from the balloon angioplasty era such as the second Randomized Intervention Treatment of Angina (RITA‐2) [9] and the Angioplasty Compared to Medicine (ACME) trials [10]. The studies and meta‐analyses of the randomized trials [12,13] demonstrates that PCI does not reduce the likelihood of death or myocardial infarction, but is more effective in relieving angina in patients with single and multivessel disease. Notably, there was an early hazard associated with PCI due to a greater likelihood of periprocedural myocardial infarction, a consistent finding in subsequent interventional trials. In addition, balloon angioplasty was associated with a high rate of emergency CABG, but this is no longer the case in contemporary practice due to the routine use of stents.
The COURAGE trial randomization 2287 patients to either optimal medical therapy alone or PCI with bare metal stents (with optimal medical therapy) [14]. Approximately two‐thirds had multivessel disease). The inclusion criteria were either a coronary stenosis ≥80% and classic angina without provocative stress testing, or a stenosis ≥70% in at least one proximal epicardial coronary artery and objective evidence of myocardial ischemia. A large number of patients were excluded from the trial because of high risk features such as a strongly positive stress test, persistent CCS class IV angina, an ejection fraction of <30%, refractory heart failure or cardiogenic shock, revascularization within the previous six months, and those with coronary anatomy unsuitable for PCI. During a median follow‐up duration of approximately five years, there was no difference in the primary composite endpoint of death and nonfatal myocardial infarction. These findings must be interpreted in light of the facts that less than 10% of the patients screened met eligibility criteria for enrolment, 85% of patients were male, and that randomization was performed in the cardiac catheterization laboratory following angiography, which may have contributed to selection bias. Revascularization rates during follow‐up were lower in the PCI arm (21.1% vs 32.6%) and may have been lower had drug‐eluting stents (DES) been used. PCI was associated with a small reduction in the requirement for anti‐anginal therapy and greater likelihood of freedom from angina; however, this benefit diminished over time. Crossover to PCI in the medical arm was due to inadequate control of symptoms.
The importance of risk stratification based on the magnitude of ischemic burden has been investigated in the ISCHEMIA trial. 5179 patients with at least moderate ischemia were randomized to an initial invasive strategy of angiography and revascularization (PCI or CABG), if feasible, in addition to optimal medical therapy or optimal medical therapy initially with revascularization reserved for failure of medical therapy. Importantly, enrollment into the trial was prior to diagnostic angiography to reduce selection bias. There was no significant difference in the primary composite endpoint of cardiovascular death, nonfatal MI, resuscitated cardiac arrest, or hospitalization for unstable angina or heart failure (HR:0.93, CI:80‐1.08;p=0.34) during approximately three year follow‐up.
