Ischemic Heart Disease: Which Test to Use?

New-onset, stable chest pain among patients without known coronary artery disease (CAD) is a common clinical problem that results in approximately 4 million stress tests annually in the United States. Significant variations in diagnostic strategies are well documented and may be related to differences in health care systems, access to testing technologies, and risk tolerance. ^, Furthermore, there are limited information on health-related outcomes in this stable, undiagnosed population and little consensus about which test is preferable or even when one is required. ^, In fact, major US and European guidelines have differed in their basic approaches and recommendations and are evolving rapidly with the availability of results from randomized trials comparing functional versus anatomical testing strategies. ^, The aims of this chapter are to provide a concise approach to noninvasive test selection based on recent guidelines and emerging evidence to:

• 1.

  Understand important patient characteristics and risk stratification algorithms that impact noninvasive test selection for the diagnosis of CAD.

• 2.

  Compare current guideline recommendations from the different professional organizations.

• 3.

  Incorporate recent data to enhance test selection through use of a unified approach for both functional and anatomical strategies.

Patient Selection for Noninvasive Testing

Clinical Classification of Chest Pain

The current discussion applies specifically to stable, symptomatic patients with suspected ischemic heart disease (IHD) on the basis of a through history physical examination and laboratory data. Symptoms are classified as typical, atypical, or noncardiac to quantify the pretest probability (PTP) of underlying coronary disease. Because the classic Diamond-Forrester algorithm significantly overestimates the degree of obstructive CAD, ^{, , ,} use of the modified algorithm proposed in the 2019 European Society of Cardiology (ESC) Diagnosis and Management of Chronic Coronary Syndromes Guidelines is warranted. This algorithm applies recent CAD prevalence in relevant outpatient populations to traditional DF risk categories to provide contemporary PTP ( Table 40.1 ).

TABLE 40.1

Pretest Probabilities of Obstructive Coronary Artery Disease in 15,815 Symptomatic Patients According to Age, Sex, and the Nature of Symptoms in a Pooled Analysis of Contemporary Data ^{, ,}

Adapted with permission from Knuuti J, et al: 2019 ESC Guidelines for the diagnosis and management of chronic coronary syndromes, Eur Heart J 41:407–477, 2020.

^a In addition to the classic Diamond and Forrester classification, patients with dyspnea only or dyspnea as the primary symptom are included. The regions shaded dark green denote the groups in which noninvasive testing is most beneficial (pretest probability [PTP] >15%). The striped regions in light green denote the groups with PTPs of coronary artery disease between 5% and 15%, in whom testing for diagnosis may be considered after assessing the overall clinical likelihood based on the modifiers of PTPs ( Fig. 40.2 ).

Approaches to Patient Selection

Diagnostic testing is most valuable when the PTP of IHD is intermediate because Bayesian analysis dictates that the application of a test result drives the posttest probability sufficiently lower (negative test) or higher (positive test) only in this range and thus the enhancement of future decision making. Whether the patient should proceed to cardiac catheterization is limited to those with intermediate PTP. Although there is no strict definition of intermediate PTP, 10% to 90%, first advocated in 1980, has been applied in several studies and is the current definition used in the 2012 American College of Cardiology/American Heart Association (ACC/AHA) guidelines for stable IHD ^, and 2014 ACC Appropriate Use Criteria Task Force document. In contrast, the current ESC guidelines advocate testing patients with a PTP greater than 15% ( Table 40.2 ), and those 5% to 15% after assessing the overall clinical likelihood based on modifiers of PTP ( Fig. 40.1 ). In contrast, the UK National Institute of Health and Care Excellence (NICE) has abandoned this probabilistic approach in favor of a symptom-focused assessment, with patients having typical or atypical symptoms or an abnormal resting electrocardiogram recommended to have coronary computed tomography angiography (CCTA). The remainder are classified as nonanginal, and no further testing is recommended. This symptom-focused assessment identifies a larger group of low-risk chest pain patients potentially deriving limited benefit from noninvasive testing. In fact, identifying chest pain patients based on baseline characteristics who may not receive any benefit from testing is an area of ongoing interest. If the patient is unlikely to benefit from revascularization, then optimizing medical therapy with a no testing strategy is likely a reasonable approach. Similarly, a patient who is very low risk may be unlikely to benefit from testing.

TABLE 40.2

Selected Guideline Recommendations for the Use of Noninvasive Testing for the Diagnosis of Ischemic Heart Disease

	AHA/ACC (2012)	ESC (2019)	NICE (2016)
Patient Selection
Risk score to calculate PTP	Combined Diamond Forrester–CASS	Knuuti et al.	Symptom based (typical or atypical chest pain)
Intermediate PTP	10%–90%	>15% 5%–15% (with modifiers)	Symptom based (typical or atypical chest pain)
Test Selection
Exercise treadmill test alone for the diagnosis of CAD a	Class I	Class IIb (evaluate CAD)	Second line if diagnosis is uncertain after CCTA
Stress imaging for the diagnosis of CAD b	Class IIa	Class I	Second line if diagnosis is uncertain after CCTA
Stress imaging if nonevaluable ECG	Class I	Class I	Second line if diagnosis is uncertain after CCTA
Stress imaging if CCTA has shown CAD of uncertain functional significance	Not specified	Class I	Second line if diagnosis is uncertain after CCTA
Anatomical (CTA) Test Selection
CCTA for the diagnosis of CAD	IIb (can exercise) IIa (cannot exercise)	Class I	First line
Nonconclusive functional test or contraindications	Class IIa	Class IIa	Not applicable

CAD, coronary artery disease; CASS, Coronary Artery Surgery Study; CCTA, coronary computed tomography angiography; ESC, European Society of Cardiology; NICE, National Institute of Health and Care Excellence; PTP, pretest probability.

a Able to exercise with an evaluable electrocardiogram (ECG).

b American College of Cardiology/American Heart Association (ACC/AHA) quantify risk as “intermediate to high.”