Hints in the full text: "...it might be unethical to expose patients to an invasive placebo procedure. However, no evidence of harm to placebo groups was found

Hints in the full text: "...it might be unethical to expose patients to an invasive placebo procedure. However, no evidence of harm to placebo groups was found in a systematic review of placebo-controlled surgical trials... After the follow-up assessments, study participation was complete, and patients and physicians were then unblinded to the treatment group allocation. Patients who had the placebo procedure had the opportunity to choose to undergo PCI after consultation with their physician." But yes, it must have taken a lot of persuasion to get through ethical approval.