Clinical trials

The management of patients with unprotected left main coronary artery (LMCA) disease undergoing percutaneous coronary intervention (PCI) in contemporary interventional cardiology practice remains matter of intense debate. Particularly, the combination of the optimal drug-eluting stent (DES) selection and antiplatelet regimen for patients who require LMCA PCI remains undetermined. Newer-generation drug-eluting stents with ultrathin-strut metallic platforms have been shown to reduce the risk of target lesion failure compared with thicker-strut drug-eluting stents among all-comer patients undergoing PCI, a difference mainly driven by a lower risk of ischemia-driven target lesion revascularization. In the TALENT prospective, single-blind, multicenter, randomized controlled trial that included 1'435 all-comer patients undergoing PCI, the Supraflex ultrathin-strut biodegradable polymer sirolimus-eluting stent was found non-inferior to the Xience® thin-strut permanent polymer everolimus-eluting stent (Abbott Vascular, USA) with regards to the device-oriented composite clinical endpoint (DoCE), a composite of cardiac death, target vessel myocardial infarction, or clinically indicated target lesion revascularization, at 12 months of follow-up. However, the TALENT trial included only 31 (1.5%) lesions located in the left main coronary artery. In the COMPARE 60/80 HBR investigator-initiated, multicenter, prospective randomized trial which included a total of 732 patients at high-bleeding risk undergoing PCI with the Supraflex Cruz ultrathin-strut biodegradable polymer sirolimus-eluting stent or the Ultimaster Tansei (Terumo Corp., Tokyo, Japan), the rates of the primary endpoint of the net adverse clinical endpoint, defined as a composite of cardiac death, myocardial infarction, target vessel revascularization, stroke, or BARC 3 or 5 major bleeding events at 12 months were similar in the Supraflex Cruz and the Ultimaster Tansei groups, meeting the prespecified criterion for non-inferiority of the Supraflex Cruz DES compared to the Ultimaster Tansei DES. The safety and efficacy of the Supraflex Cruz ultrathin-strut biodegradable polymer sirolimus-eluting stent combined with potent P2Y12 inhibitor aspirin-free SAPT among all-comer patients undergoing PCI for complex coronary lesions, such as patients with LMCA stenosis, have however not been investigated to date. Recent evidence from a large-scale meta-analysis of several randomized clinical trials including \>32'000 patients indicated that 1-3 months of DAPT followed by P2Y12 inhibitor single antiplatelet therapy (SAPT) after second-generation DES implantation was associated with lower risk for major bleeding and similar risk for adverse ischemic outcomes compared with conventional DAPT. These findings suggest that P2Y12 inhibitor SAPT following a short DAPT course (1-3 months) may represent a valuable treatment option for patients undergoing PCI with newer-generation DES compared to standard conventional 12 months DAPT, but this strategy has never been investigated in dedicated randomized clinical trials focused on patients at highest-risk for ischaemic events, such as patients undergoing LMCA PCI. The ULTIMATE-LM randomized trial aims at filling this current gap of knowledge, which may have large impact on clinical practice and international guidelines. ULTIMATE-LM will be the first randomized clinical trial to investigate the safety and efficacy of a novel ultrathin-strut biodegradable polymer drug-eluting stent (Supraflex Cruz, Sahajanand Medical Technologies Ltd., Surat, India)) combined with P2Y12 inhibitor-based single antiplatelet therapy among patients undergoing PCI for LMCA disease.

Primary percutaneous coronary intervention (PCI) is the preferred revascularization strategy for patients with acute ST-segment elevation myocardial infarction (STEMI). Compared with bare-metal stents (BMS) and early-generation thick-strut polymer-based drug-eluting stents (DES), newer-generation DES with thinner strut stent platforms and durable or biodegradable polymers have been shown to improve long-term safety and efficacy outcomes among patients with STEMI. Accordingly, the use of newer-generation DES over BMS is currently recommended by the most recent guidelines. Vessel healing at the culprit site after DES implantation is however substantially delayed in patients with acute STEMI as compared to those with chronic coronary syndromes and is associated with a long-term risk for recurrent stent-related adverse clinical outcomes. These findings highlight the need for future iterations in modern DES technology to further improve clinical outcomes following PCI in this highest-risk patient subset. Current guidelines recommend dual antiplatelet therapy (DAPT) consisting of aspirin and a potent P2Y12 receptor inhibitor for 12 months after primary PCI for STEMI, unless there are contraindications such as excessive risk of bleeding. A recent meta-analysis of five large-scale randomized clinical trials including a total of 32'145 patients, of whom 4,070 (12.7%) patients were treated for STEMI, indicated that 1-3 months of DAPT followed by P2Y12 inhibitor-based single antiplatelet therapy (SAPT) after second-generation DES implantation in patients with chronic and acute coronary syndromes was associated with lower risk for major bleeding and similar risk for stent thrombosis, all-cause death, myocardial infarction, and stroke compared with conventional DAPT. These findings suggest that a potent P2Y12 inhibitor-based SAPT following a short DAPT course (1-3 months) may represent a preferable treatment option, which is associated with similar ischemic, but lower bleeding risk, for patients undergoing PCI with newer-generation DES compared to standard conventional 12 months DAPT. The question of whether SAPT using a potent oral P2Y12 inhibitor (ticagrelor or prasugrel) without aspirin (aspirin-free strategy) after primary PCI with a newest-generation thin-strut polymer-free drug-eluting stent is safe and effective compared to a conventional guideline-recommended 6- to 12-month DAPT course among patients with STEMI remains uncertain.

The use of the distal radial artery has recently emerged as a promising alternative access route to further reduce the risk of radial artery occlusion (RAO) and has been endorsed by recent International Consensus documents. The feasibility of a distal radial access (DRA) for coronary angiography and/or PCI has been demonstrated in several observational clinical registries and small-sized randomized clinical trials. In the recent prospective, multicenter, open label, randomized, controlled DIStal vs Conventional RADIAL access (DISCO RADIAL) trial, DRA was associated with low and similar rates of RAO at discharge when compared to conventional TRA among patients undergoing coronary angiography and/or PCI. There is however limited evidence on the feasibility and safety of 7F DRA for PCI. In a prospective, multicenter, observational study including 41 patients undergoing CTO PCI using a left DRA with a 7F GLIDESHEATH SLENDER® (Terumo Corp., Tokyo, Japan), technical success was achieved in 90.3% of patients and procedural success was achieved in 78.1% of patients. No post-procedural DRA RAO were detected by clinical assessment and Doppler ultrasound examination, and no radial artery occlusions at the site of the forearm were found. Doppler ultrasound imaging of the DRA at one month was available in 67.6% of patients, with only one case (4.3%) of DRA RAO. This proof-of-concept study demonstrates that DRA using a 7F GLIDESHEATH SLENDER® (Terumo Corp., Tokyo, Japan) for CTO PCI is feasible and associated with a high procedural success rate and low vascular access-site complication rates. No randomized clinical trial to date has however compared the feasibility and safety of a 7F DRA versus 7F TRA for PCI of complex coronary lesions, such as chronic total occlusions (CTO), left main coronary artery disease, heavily calcified lesions, complex bifurcations, or other complex coronary lesions for whom the operator anticipates that a 7F guiding catheter is indicated.