ILUMIEN I is the largest prospective, non-randomized, observational study of percutaneous coronary intervention (PCI) procedural practice in patients undergoing intra-procedural pre- and post-PCI fractional flow reserve (FFR) and optical coherence tomography (OCT). We report on the impact of OCT on physician decision-making and the association with post-PCI FFR values and early clinical events.
Optical coherence tomography and documentary FFR were performed pre- and post-PCI in 418 patients (with 467 stenoses) with stable or unstable angina or NSTEMI. Based on pre-PCI OCT, the procedure was altered in 55% of patients (57% of all stenoses) by selecting different stent lengths (shorter in 25%, longer in 43%). After clinically satisfactory stent implantation using angiographic guidance, post-PCI FFR and OCT were repeated. Optical coherence tomography abnormalities deemed unsatisfactory by the implanting physician were identified: 14.5% malapposition, 7.6% under-expansion, 2.7% edge dissection and prompted further stent optimization based on OCT in 25% of patients (27% of all stenoses) using additional in-stent post-dilatation (81%, 101/124) or placement of 20 new stents (12%). Optimization subgroups were identified post hoc: stent placement without reaction to OCT findings ( n = 137), change in PCI planning by pre-PCI OCT ( n = 165), post-PCI optimization based on post-PCI OCT ( n = 41), change in PCI planning, and post-PCI optimization based on OCT ( n = 65). Post-PCI FFR values were significantly different ( P = 0.003) between optimization groups (lower in cases with pre- and post-PCI reaction to OCT) but no longer different after post-PCI stent optimization. MACE events at 30 days were low: death 0.25%, MI 7.7%, repeat PCI 1.7%, and stent thrombosis 0.25%.