Vascular Healing after Coronary Stenting Evaluated by Optical Coherence Tomography

Optical coherence tomography (OCT) is a novel intracoronary imaging application for the assessment of native lesions and coronary stents. The purpose of this thesis was to evaluate the safety and feasibility of frequency-domain OCT (FD-OCT) based on experiences of the Satakunta Central Hospital (I). Early vascular healing was evaluated after implantation of endothelial progenitor cell capturing (II) and bio-active titanium-nitride-oxide coated stents (III) in two studies, each with 20 patients. Vascular healing was also compared after implantation of bio-active and everolimus-eluting stents on 28 patients after 9-month follow-up (IV). Long-term vascular healing of bio-active and paclitaxel-eluting stents was assessed in the last study with 18 patients (V). The results indicate that FD-OCT is safe and feasible (I). Both bio-active and endothelial progenitor cell capturing stents showed near-complete endothelialisation after one-month follow-up, which is desirable when prolonged dual anti-platelet therapy needs to be avoided after stenting (II and III). Endothelialisation of bio-active stents showed a predictable pattern at mid-term and long-term follow up (IV and V). Endothelialisation of everolimus-eluting stents was not complete at 9 months follow-up, which may suggest that interruption of dual antiplatelet therapy at this time point may not be safe (IV). Finally, delayed vascular healing may be present in patients treated with paclitaxel-eluting stents as long as 4 years from implantation, which reinforces the previously raised concerns on the long-term safety of this device (V).