Finding the Gatekeeper to the Cardiac Catheterization Laboratory: Coronary CT Angiography or Stress Testing?

Abstract

Functional capacity is a robust predictor of clinical outcomes, and stress testing is used in current practice paradigms to guide referral to invasive coronary angiography. However, invasive coronary angiography is driven by ongoing symptoms, as well as risk of adverse outcomes. The limitations of current functional testing-based paradigms might be avoided by using coronary computed tomographic angiography (CCTA) for exclusion of obstructive coronary artery disease. The growth of CCTA has been supported by comparative prognostic evidence with CCTA and functional testing, as well as radiation dose reduction. Use of CCTA for physiological evaluation of coronary lesion-specific ischemia may facilitate evaluation of moderate stenoses, designation of the culprit lesion, and prediction of benefit from revascularization. The potential of CCTA to serve as an effective gatekeeper to invasive coronary angiography will depend, in part, on the adoption of these new developments, as well as definition of the benefit of detecting high-risk plaque for guiding the management of selected patients.

Keywords: angina; atherosclerotic; cardiac catheterization; chest pain; coronary artery disease; coronary computed tomography; plaque.

FIGURE 1. Sensitivity, Specificity, and Predictive Value of CCTA in 3 Prospective Multicenter Trials of the Diagnostic Performance of CCTA

The predictive value of a negative test is uniformly very high. ACCURACY = Assessment by Coronary Computed Tomographic Angiography of Individuals Undergoing Invasive Coronary Angiography; CCTA = coronary computed tomographic angiography; EUROPE = European study (18); MEDIC = Multicenter Evaluation of Coronary Dual-Source CT angiography in patients with intermediate Risk of Coronary Artery Stenoses; NPV = negative predictive value; PPV = positive predictive value.

FIGURE 2. Use of CCTA to Identify Angiographic Thresholds for CAD for Which ICA Is Versus Is Not Indicated (n = 15,223)

These data on observed mortality rates for patients with obstructive coronary artery disease (CAD) undergoing medical therapy (medical Tx) or revascularization (revasc) emphasize the importance of characterizing high-risk (survival benefit with revascularization) versus non–high-risk CAD (lower mortality rates when treated with medical therapy alone). Modified with permission from Min et al. (44). CCTA = coronary computed tomographic angiography.

FIGURE 3. Derivation of FFR_CT From Typical CT Acquisition

There are no requirements for modification of imaging protocols, additional image acquisition, additional radiation, or administration of adenosine. FFR_CT may be selected at any point in the coronary tree (Online Video 1). CT = computed tomography; FFR = fractional flow reserve.

FIGURE 4. Prognostic Implications of Functional Testing in Patients With CP and No Anatomic CAD

In 457 patients with chest pain (CP) (245 men; 56 ±10 years) with positive high-dose dipyridamole echocardiography (DET), the 10-year survival was approximately 75%, compared with 90% in patients with a negative test, with a similar but smaller difference for cardiac mortality (52). CAD = coronary artery disease.

FIGURE 5. Functional Disability and Angina in Women With CP

Typical angina was present in 35% to 45% of women with nonobstructive and 1- to 3-vessel coronary artery disease. Functional disability (defined by a Duke activity status index ≤4.7 metabolic equivalents) was present in one-half of these patients, even in the absence of obstructive coronary artery disease (53). CP = chest pain; VD = vein disease.

CENTRAL ILLUSTRATION. Combined Multimodality Algorithm Based Around the Use of CCTA for Chest Pain Evaluation

CAD = coronary artery disease; CCTA = coronary computed tomographic angiography; CT= computed tomography; FFR = fractional flow reserve.