The purpose of this clinical study is to evaluate the effectiveness and safety of a specialized medical device, the Naviscore scoring balloon, in preparing calcified coronary artery narrowings before the implantation of a drug-eluting stent. During percutaneous coronary interventions, the presence of calcified plaques in the heart arteries represents a major challenge because it can prevent stents from expanding fully. When a stent remains under-expanded, it significantly increases the long-term risk of arterial re-narrowing or blood clot formation. To optimize stent expansion, appropriate preparation of the diseased vessel section before stent insertion is a critical phase.

This study is a prospective, multi-center randomized trial designed to test the hypothesis that treating calcified coronary lesions with the Naviscore scoring balloon will achieve a better stent expansion and a larger final minimal stent area compared to standard lesion preparation using regular non-compliant balloons. Eligible participants will be randomized in a one-to-one ratio to one of these two lesion preparation strategies. For all included patients, standard drug-eluting stents will be deployed. The study will use intravascular ultrasound imaging to evaluate the final minimum area of the stent directly inside the treated artery at the site of the highest initial calcium burden. Participant health and clinical outcomes will be monitored for up to twelve months following the procedure.

Percutaneous transluminal coronary angioplasty (PTCA) is the main technique in percutaneous coronary intervention (PCI). It aims to restore coronary blood flow by mechanically enlarging a stenotic arterial segment through controlled balloon inflation within the vessel lumen. The acute luminal gain with balloon angioplasty is the result of multiple mechanisms, ranging from percolation and longitudinal redistribution of atheroma, to plaque fracture, and overstretching of the vessel wall, often accompanied by intimal tearing and medial dissection. While contemporary drug-eluting technologies have significantly improved long-term clinical outcomes, fibrocalcified atheromatous intracoronary plaques still present a significant challenge for stent crossing and optimal deployment.

Research has demonstrated that suboptimal stent expansion and malapposition are significant contributing factors to restenosis and stent thrombosis rates, regardless of the type of stent used. Intravascular imaging registries have identified that twenty to thirty percent of deployed stents remain under-expanded or malapposed in daily clinical practice. Severe coronary calcification can make it difficult to deliver devices and can limit the expansion of stents, which can result in suboptimal improvement in blood flow and an increased risk of adverse events, including target lesion failure. Furthermore, heavily calcified lesions have been found to be associated with higher rates of vessel dissection, perforation and impaired anti-proliferative drug delivery, resulting from the mechanical barrier of the calcium burden.

In order to achieve successful stent deployment, optimal preparation of fibro-calcific lesions is essential and involves a number of plaque modification strategies. Focused force angioplasty is a procedure that targets specific locations of the plaque, focusing inflation forces on the area to induce localized stress and facilitate cracking. It is crucial to ensure that the pre-dilatation balloon is correctly sized to maximise safety by minimising the risk of advanced coronary perforation or severe medial damage. It is imperative that sizing compliance chart data is followed rigorously, as compliant balloons can display an unpredictable non-linear expansion behaviour at higher pressures, whereas non-compliant balloons maintain a stable volume, concentrating their dilating force directly at the calcified site up to their rated burst pressure. Semi-compliant pre-dilatation balloons often expand asymmetrically in resistant lesions, increasing the risk of edge dissections. The sizing and performance of scoring devices and non-compliant balloons remains limited in contemporary clinical literature. This randomised trial is designed to evaluate the post-market clinical performance, safety and comparative effectiveness of the Naviscore scoring balloon catheter manufactured by iVascular.

Inclusion Criteria:

• Patient written consent is given, ≥18 years.
• A de novo lesion to be treated in a vessel between 2.5 and 4.0 mm.
• Moderate to heavily calcified lesions detected by coronary angiography on two orthogonal views, and confirmed by IVUS if the lesion can be crossed with the catheter.

Exclusion Criteria:

• Patient <18 years old.
• Pregnant female.
• Contraindication to dual antiplatelet therapy.
• Thrombocytopenia (under 100 000).
• Major surgical intervention planned within one year.
• Significant left main lesion.
• Chronic total occlusion.
• Lesion in a graft.
• In-stent restenosis lesion.
• Lesion responsible of a ST elevated Myocardial Infarction (STEMI)

The individual participant data (IPD) that underlie the results reported in this publication, including the final minimal stent area (MSA) measurements, procedural success data, and relevant clinical adverse event records, will be shared. Supporting documents, including the study protocol, statistical analysis plan, and informed consent forms, will be provided to support the interpretation of the IPD. All data shared will be de-identified to maintain participant confidentiality in accordance with GDPR requirements.

Beginning 6 months after the publication of the study results and ending 5 years following the publication date.

Access is granted to researchers who provide a methodologically sound proposal for secondary analysis. Proposals must be submitted to the Principal Investigators at the University of Mons (UMONS), Belgium. The study's Steering Committee will review each request. Upon approval, data will be shared under a signed data sharing agreement ensuring strict adherence to participant privacy and institutional ethical guidelines.