Percutaneous coronary intervention in stable angina (ORBITA): a double-blind, randomised controlled trial

Selected in The Lancet by S. Brugaletta

References

Authors

Al-Lamee R, Thompson D, Dehbi HM, Sen S, Tang K, Davies J, Keeble T, Mielewczik M, Kaprielian R, Malik IS, Nijjer SS, Petraco R, Cook C, Ahmad Y, Howard J, Baker C, Sharp A, Gerber R, Talwar S, Assomull R, Mayet J, Wensel R, Collier D, Shun-Shin M, Thom SA, Davies JE, Francis DP; ORBITA investigators.

Reference

Lancet. 2017 Nov 1. pii: S0140-6736(17)32714-9

Published

November 2017

Link

Read the abstract

My Comment

Why this study – the rationale/objective?

Symptomatic relief is the primary goal of percutaneous coronary intervention (PCI) in stable angina and is commonly observed clinically. However, there is no evidence from blinded, placebo-controlled randomised trials to show its efficacy. The objective of this trial was to assess the effect of PCI versus placebo on exercise time in patients with stable ischaemic symptoms.

How was it executed – the methodology?

ORBITA is a blinded, multicentre randomised trial of PCI versus a placebo procedure for angina relief that was done at five study sites in the UK. We enrolled patients with severe (≥70%) single-vessel stenoses. After enrolment, patients received 6 weeks of medication optimisation.
Patients then had pre-randomisation assessments with cardiopulmonary exercise testing, symptom questionnaires, and dobutamine stress echocardiography. Patients were randomised 1:1 to undergo PCI or a placebo procedure by use of an automated online randomisation tool.
After 6 weeks of follow-up, the assessments done before randomisation were repeated at the final assessment. The primary endpoint was the difference in exercise time increment between groups. All analyses were based on the intention-to-treat principle and the study population contained all participants who underwent randomisation.

What is the main result?

ORBITA enrolled 230 patients with ischaemic symptoms. After the medication optimisation phase and between Jan 6, 2014 and Aug 11, 2017, 200 patients underwent randomisation, with 105 patients assigned PCI and 95 assigned the placebo procedure. Lesions had mean area stenosis of 84·4% (SD 10·2), fractional flow reserve of 0·69 (0·16), and instantaneous wave-free ratio of 0·76 (0·22). There was no significant difference in the primary endpoint of exercise time increment between groups (PCI minus placebo 16·6 s, 95% CI –8·9 to 42·0, p=0·200). There were no deaths. Serious adverse events included four pressure-wire related complications in the placebo group, which required PCI, and five major bleeding events, including two in the PCI group and three in the placebo group.

Critical reading and the relevance for clinical practice

This is a very provocative trial, comparing PCI vs. optimal medical treatment (OMT) in one-vessel disease. Many interesting points of discussion arise from this trial. The selected primary endpoint was the increase in exercise time in PCI vs. OMT arm. The superiority of PCI vs. OMT was set on a 30 seconds increase. The final result was a 16 seconds increase, which could be explained by too much optimistic sample size.
More interesting is that either PCI or OMT patients received iFR/FFR evaluation, without any differences between groups in terms of absolute values. However, as previous studies demonstrated that defer-group exhibited more events than PCI-group, it is unclear whether in this low-risk population, it could be the possibility that a negative or positive iFR/FFR should not influence treatment. We are curious about the opinion of our community on this trial and on its possible impact in our clinical practice.

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