Percutaneous coronary intervention versus medical therapy in patients with angina and grey-zone fractional flow reserve values: a randomised clinical trial

IntroductionThere is conflicting evidence regarding the benefits of percutaneous coronary intervention (PCI) in patients with grey zone fractional flow reserve (GZFFR artery) values (0.75–0.80). The prevalence of ischaemia is unknown. We wished to define the prevalence of ischaemia in GZFFR artery and assess whether PCI is superior to optimal medical therapy (OMT) for angina control.MethodsWe enrolled 104 patients with angina with 1:1 randomisation to PCI or OMT. The artery was interrogated with a Doppler flow/pressure wire. Patients underwent Magnetic Resonance Imaging (MRI) with follow-up at 3 and 12 months. The primary outcome was angina status at 3 months using the Seattle Angina Questionnaire (SAQ).Results104 patients (age 60±9 years), 79 (76%) males and 79 (76%) Left Anterior Descending (LAD) stenoses were randomised. Coronary physiology and SAQ were similar. Of 98 patients with stress perfusion MRI data, 17 (17%) had abnormal perfusion (≥2 segments with ≥25% ischaemia or ≥1 segment with ≥50% ischaemia) in the target GZFFR artery. Of 89 patients with invasive physiology data, 26 (28%) had coronary flow velocity reserve