Selecting target lesion(s)

7.1.1

Symptoms?

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):

• 1.

  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 .

• 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 .

7.1.2

CAD extent

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.

7.1.3

Prior CABG

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 .

7.1.4

Diabetes mellitus

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 .

7.1.5

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 ( http://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 ( http://www.euroscore.org/calc.html ).

The following factors are assessed:

Cardiac

• 1.

  Recent acute coronary syndrome

• 2.

  Urgency of the operation

• 3.

  Angina severity

• 4.

  Left ventricular function

• 5.

  Congestive heart failure

• 6.

  Pulmonary hypertension

• 7.

  Valvular heart disease

• 8.

  Active endocarditis

• 9.

  Prior cardiac surgery

• 10.

  Porcelain aorta

• 11.

  Atrial fibrillation

• 12.

  Heart block

• 13.

  Cardiogenic shock

Noncardiac

• 1.

  Age

• 2.

  Gender

• 3.

  Height and weight

• 4.

  Mobility

• 5.

  Renal disease

• 6.

  Liver disease

• 7.

  Chronic lung disease

• 8.

  Peripheral arterial disease

• 9.

  Cerebrovascular disease

• 10.

  Diabetes mellitus

• 11.

  Immunocompromised status

• 12.

  Prior mediastinal radiation

• 13.

  Severe chest deformation or scoliosis

• 14.

  Illicit drug-use

• 15.

  Cancer

• 16.

  Hematocrit

• 17.

  Platelet count

• 18.

  Current medications (P2Y ₁₂ inhibitors, glycoprotein IIb/IIIa inhibitors, etc.)

• 19.

  Frailty

7.1.6

Complex CAD?

The complexity of CAD is most commonly assessed using the Syntax score ( http://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 ) .

7.1.7

Factors potentially associated with improved prognosis with coronary revascularization

Coronary revascularization in stable CAD patients is mainly done to improve symptoms as discussed in Section 7.1.1 , but could also improve prognosis in the following patient subgroups :

• Left main disease with stenosis >50%.

• Proximal LAD stenosis >50%.

• Two- or three-vessel disease with stenosis >50% and impaired LV function (LVEF ≤35%).

• Large area of ischemia detected by functional testing (>10% LV) or abnormal invasive FFR.

• Single remaining patent coronary artery with stenosis >50%.

• Sudden cardiac death due to ventricular fibrillation or ventricular tachycardia.

7.1.8

Benefits versus risks

( Fig. 7.3 )

Before proceeding with PCI the risks and benefits need to be assessed to ensure that benefits outweigh the risks. Estimation of the risks and benefits can be based on the following four areas:

• 1.

  Impact of CAD

  The more severe the impact of CAD on the patient’s clinical condition (e.g., severe angina even with minimal exertion), the greater the potential benefit of PCI.

• 2.

  Operator competence

  Greater operator experience is associated with higher success and lower complication rates. Experienced operators may also be more adept in managing complications should they occur. Moreover, the operator and staff condition (e.g., well rested and not-sleep deprived, etc.) can affect the outcome of the procedure .

• 3.

  Lesion(s) complexity

  More complex lesions (such as CTOs, heavily calcified lesions, bifurcations, etc.) can be more challenging to recanalize and carry increased risk of complications.

• 4.

  Comorbidities

  More comorbidities may increase the risk of the procedure and decrease the benefits (e.g., coronary revascularization should not be performed with the goal to improve prognosis in patients with noncardiac terminal disease, such as cancer).

7.1.9