The following decisions need to be made after coronary angiography is performed.
Is coronary revascularization needed?
Like every other procedure, coronary revascularization should be done when the anticipated benefits exceed the potential risks. Potential benefits are improving symptoms and improving prognosis. This is discussed separately for patients with stable angina ( Section 7.1 ) and for patients with acute coronary syndromes (ACS) ( Section 7.2 ).
If yes, should it be done with percutaneous coronary intervention (PCI) or coronary artery bypass graft surgery (CABG)?
PCI and CABG have advantages and disadvantages: PCI is generally easier to perform and carries lower upfront risk, but is associated with higher need for repeat revascularization compared with CABG. The choice of revascularization modality is discussed in Sections 7.1 and 7.2 .
If PCI is selected, which lesions should be treated, in-which sequence and with what techniques?
Target lesion selection depends on clinical presentation (e.g., culprit lesions should be treated first in ACS patients), lesion location and lesion complexity. This is discussed in Section 7.3 .
Algorithms for determining the need, modality, and sequence (in case of PCI) of coronary revascularization are discussed in the following sections.
Stable angina – Chronic Coronary Syndromes
( Fig. 7.1 )
The goal of coronary revascularization is to improve symptoms (help patients feel better) or improve prognosis (live longer or reduce risk of subsequent unwanted events, such as myocardial infarction).
The following symptoms are often caused by coronary artery disease (CAD):
Chest pain that is provoked by exertion and relieved by rest. Chest pain at rest is the hallmark of acute coronary syndromes and is discussed in Section 7.2 .
Dyspnea, which is a frequent “anginal equivalent.”
Symptoms can only be improved if they are present at baseline! In other words, asymptomatic patients cannot feel better after coronary revascularization. Some patients, however, deny symptoms in part because they gradually limit their activities. Obtaining information from their family and performing an exercise stress test can help determine if a patient is truly asymptomatic or not.
Coronary revascularization is more effective in relieving angina than medical therapy , reduces or eliminates the need for antianginal medications and improves quality of life, but is not associated with improved prognosis (lower risk of myocardial infarction or death) in stable CAD patients except possibly in patients with high-risk coronary anatomy as described in Sections 7.1.2 and 7.1.7 .
The extent of CAD is a key determinant of whether coronary revascularization is needed and of the optimal type of coronary revascularization (PCI or CABG).
With the exception of highly stenotic coronary lesions (diameter stenosis ≥90%), that are almost always hemodynamically significant, coronary physiology ( Chapter 12 : Coronary physiology) can help more accurately determine the severity of CAD .
Patients with single-vessel disease are in most cases treated with PCI.
Patients with multivessel (or left main) coronary artery disease can be treated with either PCI or CABG:
PCI is preferred for prior CABG patients, poor surgical candidates, and patients with less complex CAD.
CABG is preferred for patients with diabetes, reduced ejection fraction, and patients with complex multivessel CAD, as discussed in more detail below.
Due to increased risk of death and complications, redo CABG is performed infrequently in patients who have already had CABG . However, redo CABG could be considered in patients with severely diseased or occluded bypass grafts, native vessels not amenable to PCI, depressed left ventricular ejection fraction and absence of patent arterial grafts. Internal mammary artery grafts should be used, if feasible, in patients undergoing reoperation .
Patients with diabetes mellitus and multivessel CAD had better outcomes with CABG (including lower mortality) in several trials (although most, but not all , such studies included first generation drug-eluting stents [DES]). This is likely due to higher risk of restenosis and disease progression in non-stented coronary segments or vessels in diabetic patients and has been linked to the use of left internal mammary artery to left anterior descending (LIMA-LAD) grafts. Hence, CABG is generally preferred for diabetic patients with multivessel CAD, who are good surgical candidates .
Good surgical candidate?
The risk of CABG depends on the patients’ cardiac status and noncardiac comorbidities.
This is often assessed using the Society of Thoracic Surgeons (STS) score ( riskcalc.sts.org/stswebriskcalc/ ) that predicts in-hospital or 30-day mortality and in-hospital morbidity, or the Euroscore II that predicts in-hospital mortality ( www.euroscore.org/calc.html ).
The following factors are assessed:
Recent acute coronary syndrome
Urgency of the operation
Left ventricular function
Congestive heart failure
Valvular heart disease
Prior cardiac surgery
Height and weight
Chronic lung disease
Peripheral arterial disease
Prior mediastinal radiation
Severe chest deformation or scoliosis
Current medications (P2Y 12 inhibitors, glycoprotein IIb/IIIa inhibitors, etc.)
The complexity of CAD is most commonly assessed using the Syntax score ( www.syntaxscore.com/ ) , which incorporates extent of disease and angiographic characteristics, such as lesion location, diameter stenosis, presence of bifurcations or trifurcations, aorto-ostial location, severe tortuosity, lesion length, calcification, thrombus, and vessel size ( Fig. 7.2 , Table 7.1 ) .