Percutaneous coronary intervention with evolving stent technology for treating totally occluded native coronary arteries

Chronic total coronary occlusions (CTO) remain the most complex lesions for percutaneous revascularization. Historically, percutaneous coronary intervention of CTO was hampered by high rates of restenosis and reocclusions. The introduction of drug-eluting stents significantly improved the treatment of CTO-PCI by reducing the rate of restenosis and reocclusions. In this thesis we investigated bare metal stents and first, second -and third-generation drug-eluting stents (DES) in CTO. In the first part we focus on the efficacy and clinical safety of these stents in three multi-centre randomized clinical trials. In Chapter 2, we showed that intima proliferation is continuous at the long-term with first generation and not halted by DES. In Chapter 3 and 4 we showed worse angiographic outcome with second-generation Endeavor zotarolimus-eluting stents compared to first-generation Sirolimus-eluting stents (SES). On the other hand, non-inferiority could be established with second-generation Resolute zotarolimus-eluting stent compared to SES. In Chapter 4-8 we compared the second-generation thin-strut everolimus-eluting stent (EES) to the third-generation ultra thin-strut sirolimus-eluting stent (Hybrid SES). At 9-month, primary non-inferiority angiographic endpoint was not met for Hybrid SES with higher rate of binary restenosis compared to EES. The difference in outcome was mostly attributed in the sub-group of smaller stent diameters. EES showed higher rates of uncovered stent struts, on the other hand Hybrid SES demonstrated higher rates of malapposition and evaginations. In the last part Chapter 9 and 10, we showed that residual distal stenosis behind the CTO could be safely deferred from immediate stenting and that continuous thermodilution is a promising technique to investigate the coronary physiology.