Percutaneous coronary intervention in stable angina (ORBITA)


eMediNexus    13 February 2018

  1. Symptomatic relief is the primary goal of percutaneous coronary intervention(PCI) in stable angina and is commonly observed clinically. 
  2. However, there is no evidence from blinded, placebo-controlled randomised trials to show its efficacy.
  3. 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. 
  4. The study 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. 
  5. Patients were randomised 1:1 to undergo PCI or a placebo procedure by use of an automated online randomisation tool.
  6. After 6 weeks of follow-up, the assessments done before randomisation were repeated at the final assessment. 
  7. The primary endpoint was difference in exercise time increment between groups. 
  8. 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.
  9. 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). 
  10. 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). 
  11. 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.


In patients with medically treated angina and severe coronary stenosis, PCI did not increase exercise time by more than the effect of a placebo procedure. 


  1. A stenosis of intermediate severity, defined as a >40 to <80 percent diameter narrowing as assessed by visual inspection of the radiocontrast luminogram during coronary angiography, is encountered in almost 50 percent of patients undergoing coronary arteriography.
  2. Fractional flow reserve (FFR) is the clinical standard for the invasive physiologic assessment of the hemodynamic significance (ie, ischemic potential) of 
  3. FFR is superior to intravascular ultrasound and in many cases to noninvasive stress radionuclide myocardial perfusion imaging.
  4. For intermediate stenoses where there is a question of whether revascularization should be carried out, and there are no prior useful noninvasive physiologic data to guide decision making, FFR should be measured before the decision to implant a stent.
  5. Normal practice : Cut off level 0.8 ( > 0.8 no intervention)
  6. FFR >0.8 correlate with absence of ischemia on noninvasive testing.

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