CT vs. invasive coronary angiography in stable chest pain: Same MACE risk but less complications

Introduction and methods

Background

Invasive coronary angiography (ICA) is the reference standard to diagnose obstructive coronary artery disease (CAD) and enables coronary revascularization during the same procedure. However, elective ICA is associated with rare but major procedure-related complications [1]. CT is an accurate, noninvasive alternative to ICA in patients with stable chest pain and intermediate pretest probability of obstructive CAD [2,3].

Aim of the study

The aim of this study was to compare CT with ICA as initial diagnostic imaging strategy for guiding treatment of patients with stable chest pain who were clinically referred for ICA.

Methods

The DISCHARGE (Diagnostic Imaging Strategies for Patients with Stable Chest Pain and Intermediate Risk of Coronary Artery Disease) trial was a multicenter, pragmatic, randomized, assessor-blinded, parallel-group, superiority trial, in which 3667 patients were randomly assigned (1:1 ratio) to CT or ICA. Inclusion criteria were: age ≥30 years, referral for ICA because of stable chest pain, and intermediate pretest probability of obstructive CAD (10%–60%). Patients were recruited at one of 26 certified clinical centers in 16 European countries.

Outcomes

The primary outcome was MACE, a composite of CV death, nonfatal MI, and nonfatal stroke. An expanded primary outcome—a composite of CV death, nonfatal MI, nonfatal stroke, TIA, and major procedure-related complications—was also assessed.

Key secondary outcomes were major procedure-related complications occurring during or within 48 hours of CT/ICA, related tests, or revascularization procedures, and patient-reported outcomes (including angina pectoris during the last 4 weeks of follow-up, and health-related quality of life measured with the EQ-5D and SF-12v2).

Main results

Primary outcome

• During a median follow-up time of 3.5 years, MACE occurred in 38/1808 patients (2.1%) in the CT group and in 52/1753 (3.0%) in the ICA group (hazard ratio (HR): 0.70; 95% CI: 0.46–1.07; P = 0.10). The resulting annual rate of MACE was 0.61% and 0.86%, respectively.
• The expanded primary (composite) outcome occurred in 2.8% of the patients in the CT group and in 4.6% of those in the ICA group (HR: 0.60; 95% CI: 0.42–0.85).

Secondary outcomes

• Major procedure-related complications occurred in 9 patients (0.5%) in the CT group and in 33 patients (1.9%) in the ICA group (HR: 0.26; 95% CI: 0.13–0.55).
• Major procedure-related complications related to ICA included 11 nonfatal MIs and 1 nonfatal stroke. Of the 5 major complications not related to ICA, 1 was related to CT and 4 were associated with CABG.
• The frequency of coronary revascularization procedures was lower in the CT group (14.2%) than in the ICA group (18.0%) (HR: 0.76; 95% CI: 0.65–0.90).
• During the last 4 weeks of follow-up, angina was reported by 8.8% of the patients in the CT group and by 7.5% of those in the ICA group (odds ratio: 1.17; 95% CI: 0.92–1.48).
• Quality-of-life outcomes assessed at follow-up were also similar in the two groups.
• During follow-up, more patients in the CT group (18.6%) underwent additional functional testing than those in the ICA group (12.9%) (HR: 1.49; 95% CI: 1.26–1.76).

Conclusion

References

Find this article online at N Engl J Med.