Angina in stable coronary artery disease: Data from ORBITA and ORBITA-2.

Abstract

It is now widely accepted that in the setting of stable angina, the primary remit of percutaneous coronary intervention (PCI) is for symptom relief. However, prior to the Objective Randomised Blinded Investigation with optimal medical Therapy of Angioplasty in stable angina (ORBITA) trial, there had been no placebo-controlled trial to assess the efficacy of this common procedure to improve angina. ORBITA randomised 200 patients with significant single-vessel coronary artery disease on maximal anti-anginal medications to either PCI or a placebo procedure. The results were striking and unexpected: after 6 weeks, there was no significant difference in the primary endpoint of treadmill exercise time between groups. Questions arose; how could PCI fail to outperform a placebo procedure, despite resolving significant epicardial stenosis and ischaemia? Clearly the relationship between symptoms, ischaemia and stenosis was more complex than previously understood. ORBITA-2 was designed to assess the effect of PCI compared to placebo in patients with single or multivessel disease, without the possible attenuation of anti-anginal medication, at 12 weeks. In this setting, PCI convincingly improved symptoms, with a significant increment over placebo as assessed by the angina symptom score, a patient-orientated primary endpoint. Taken together, these trials highlight a key insight: when offered first without anti-anginal medications, PCI offers meaningful symptom benefit. When offered after anti-anginal medications, as is recommended by international guidelines, it's added benefit is much smaller. This suggests the sequence of treatment matters, with the first therapy, whether PCI or medications, yielding the most demonstrable benefit, with subsequent interventions then offering little added value. As clinicians, the decision to advocate for PCI or anti-anginal medications first, will depend on many factors including individual patient characteristics and preferences. Importantly, in the absence of a head-to-head placebo-controlled trial of PCI alone versus medication alone, the question of which approach offers the greatest symptomatic benefit remains unresolved.