Objective Randomized Blinded Investigation With Optimal Medical Therapy of Angioplasty in Stable Angina - ORBITA-2

Dec 21, 2023
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Author/Summarized by Author:
Dharam J. Kumbhani, MD, SM, FACC
Trial Sponsor:
National Institute for Health and Care Research Imperial Biomedical Research Centre
Date Presented:
11/11/2023
Date Published:
12/20/2023
Date Updated:
12/21/2023
Original Posted Date:
11/11/2023
References

Contribution To Literature:

The ORBITA-2 trial showed that among patients with stable angina and coronary stenoses causing ischemia on little or no antianginal therapy, PCI results in greater improvements in anginal frequency and exercise times compared with a sham procedure.

Description:

The goal of the trial was to assess the efficacy of percutaneous coronary intervention (PCI) compared with a sham placebo procedure for angina relief among patients with stable angina who were not on background antianginal medication.

Study Design

Patients with stable angina were randomized in a 1:1 fashion to either PCI (n = 151) or a placebo sham procedure (n = 150). At enrollment, patients ceased treatment with antianginal medications. For the PCI group, angiographic and physiological complete revascularization of the target vessels was mandated, and intravascular imaging was encouraged. In patients with multivessel coronary artery disease (CAD), all the vessels were treated during the index procedure. The patients in the placebo group remained sedated, without any further intervention, for at least 15 minutes after randomization.

  • Total screened: 923
  • Total number of enrollees: 301
  • Duration of follow-up: 12 weeks
  • Mean patient age: 64 years
  • Percentage female: 21%

Inclusion criteria:

  • Considered to be clinically suitable for PCI by the referring heart team
  • Had angina or symptoms equivalent to those with angina
  • Had anatomical evidence of at least one severe coronary stenosis that was identified on invasive diagnostic coronary angiography or coronary computed tomographic angiography
  • Had evidence of ischemia on the basis of noninvasive imaging or invasive coronary physiological test

Exclusion criteria:

  • Age <18 years
  • Age >85 years
  • Recent acute coronary event
  • Previous coronary artery bypass graft surgery
  • Significant left main stem CAD
  • Chronic total occlusion in the target vessel
  • Contraindication to PCI or drug-eluting stent implantation
  • Contraindication to antiplatelet therapy
  • Severe valvular disease
  • Severe left ventricular (LV) systolic impairment
  • Severe respiratory disease
  • Life expectancy <2 years, pregnancy, unable to consent

Other salient features/characteristics:

  • LV ejection fraction normal: 96%
  • Canadian Cardiovascular Society (CCS) angina severity class: I (4%), II (58%), III (39%)
  • Angina duration: 8 months
  • Vessel involved: left anterior descending (55%), right coronary artery (22%), left circumflex (9%), branch vessels (14%)
  • Median baseline fractional flow reserve value: 0.63; median baseline instantaneous wave free ratio value: 0.78

Principal Findings:

The primary outcome, mean angina symptom score for PCI vs. placebo, was: 2.9 vs. 5.6 (odds ratio [OR] 2.21, 95% confidence interval [CI] 1.41-3.47, p < 0.001).

  • Mean daily angina frequency: 0.3 vs. 0.7 (OR 3.44, 95% CI 2.00-5.91)

Secondary outcomes for PCI vs. sham:

  • Mean treadmill exercise time: 700.9 vs. 641.4 seconds
  • Seattle Angina Questionnaire–freedom from angina: 80.6 vs. 66.2
  • CCS class: 0.9 vs. 1.7

Interpretation:

The results of this trial indicate that, among patients with stable angina and coronary stenoses causing ischemia on little or no antianginal therapy, PCI results in greater improvements in anginal frequency and exercise times compared with a sham procedure.

These are important findings. Results are in contrast to the ORBITA trial, where no benefit was noted with PCI on top of optimal medical therapy for the primary endpoint of treadmill exercise time. This trial helps confirm the antianginal benefit of PCI for stable CAD in a sham-controlled design, which is important. Limitations include the short duration of follow-up (12 weeks) and the relatively small sample size, which precludes assessment of meaningful clinical endpoints.

References:

Highlighted text has been updated as of December 21, 2023.

Rajkumar CA, Foley MJ, Ahmed-Jushuf F, et al., on behalf of the ORBITA-2 Investigators. A Placebo-Controlled Trial of Percutaneous Coronary Intervention for Stable Angina. N Engl J Med 2023;389:2319-30.

Editorial: White HD. Changing the Orbit Around Percutaneous Coronary Intervention for Stable Angina. N Engl J Med 2023;389:2387-8.

Presented by Dr. Christopher Rajkumar at the American Heart Association Scientific Sessions, Philadelphia, PA, November 11, 2023.

Clinical Topics: Invasive Cardiovascular Angiography and Intervention

Keywords: AHA23, Myocardial Ischemia


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