Evaluation of Calcified Coronary Lesion Preparation With the Naviscore Scoring Balloon (MILOU)

June 10, 2026 updated by: Stephane Carlier, University of Mons

MILOU: Minimize Intra Luminal Obstructive Underexpansion: A Prospective, Multi-Center Randomized Trial for the Evaluation of Calcified Coronary Lesion Preparation With the Naviscore Scoring Balloon

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.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

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.

Study Type

Interventional

Enrollment (Estimated)

200

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • Belgium
      • Bonheiden, Belgium, 2820
        • Imelda
      • Brussels, Belgium, 1070
        • Hôpital Erasme - Cliniques universitaires de Bruxelles
        • Contact:
        • Principal Investigator:
          • Gabriela Flores Vivian, MD
      • Libramont, Belgium, 6800
        • Hôpital Vivalia
        • Contact:
        • Principal Investigator:
          • Chadi Ghafari, MD, PhD
      • Liège, Belgium, 4000
      • Lodelinsart, Belgium, 6042
        • Humani CHU Charleroi - Chimay
        • Contact:
        • Principal Investigator:
          • Mohamed Ben Yedder, MD
    • Hainaut
      • Mons, Hainaut, Belgium, 7000
        • CHU - HELORA site Kennedy
        • Contact:
        • Principal Investigator:
          • Stéphane Carlier, MD, Phd
  • Luxembourg
      • Luxembourg, Luxembourg, 1210
        • INCCI Haerz Zenter
        • Contact:
        • Principal Investigator:
          • Bruno Pereira, MD
  • Portugal
      • Vila Nova de Gaia, Portugal, 4430-999
        • Centro Hospitalar de Vila Nova de Gaia/Espinho
        • Contact:
        • Principal Investigator:
          • Alberto Rodrigues, MD
  • Spain
      • Barcelona, Spain, 08025
        • Hospital de Sant Pau
        • Contact:
        • Contact:
          • Elena Jiménez Xarrié
          • Phone Number: +34628839525
        • Principal Investigator:
          • Estefanía Fernández-Peregrina, MD
      • Barcelona, Spain, 08901-08908
      • Cadiz, Spain, 11009
        • Hospital Puerta del Mar
        • Contact:
        • Principal Investigator:
          • Alejandro Gutiérrez-Barrios, MD
      • Cáceres, Spain, 10003
        • Hospital San Pedro De Alcantara
        • Contact:
        • Principal Investigator:
          • Juan Carlos Rama, MD
      • Valencia, Spain, 46026
        • Hospital La Fe
        • Contact:
        • Contact:
        • Principal Investigator:
          • Jorge Sanz Sanchez, MD
      • Valladolid, Spain, 47003
        • Hospital Clínico Universitario de Valladolid
        • Principal Investigator:
          • Ignacio J Amat Santos, MD
        • Contact:
          • Ignacio J Amat Santos, MD
          • Phone Number: 86571 +34983420000
          • Email: ijamat@gmail.com
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

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)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Standard NC group
Lesion preparation of calcified coronary stenosis performed using standard non-compliant (NC) balloons. Balloons are sized according to a 0.8:1 to 1:1 ratio relative to the reference lumen and inflated below the rated burst pressure. To maintain a strict comparison and eliminate any scoring effect, no parallel guidewire is allowed in the target vessel during inflation.
Device: Non-Compliant (NC) Angioplasty Balloon
Conventional non-compliant (NC) PTCA balloon catheter used for standard lesion pre-dilatation according to routine clinical practice, inflated below the rated burst pressure without parallel guidewires in place.
Other Names:
  • Conventional PTCA Balloon
Experimental: Naviscore group
Lesion preparation of calcified coronary stenosis performed using the Naviscore scoring balloon catheter before drug-eluting stent implantation. The device is sized according to a 0.8:1 to 1:1 ratio relative to the reference lumen. To maximize the plaque-modification effect of the external nitinol wires, a mandatory mechanical mobilization sequence must be performed: the balloon is inflated to nominal pressure, fully deflated, mobilized within the lesion, and reinflated. This specific sequence must be repeated 3 to 4 times across the target segment.
Device: Scoring Balloon PTCA Catheter
Percutaneous coronary preparation of calcified coronary stenosis using the rapid exchange Naviscore scoring balloon catheter before drug-eluting stent deployment. The device incorporates an over-the-balloon metallic nitinol element designed to focally concentrate dilation forces, minimizing balloon slippage and scoring the atheromatous plaque at lower pressures to facilitate optimal stent expansion. Sizing is based on a 0.8:1 to 1:1 ratio relative to the reference lumen. Operators must execute a specific sequence of inflating the scoring balloon to nominal pressure, fully deflating it, mobilizing it within the lesion, and reinflating it, repeated three to four times across the target segment to ensure multi-focal plaque disruption before stenting.
Other Names:
  • Naviscore Scoring Balloon

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Final Minimal Stent Area (MSA)
Time Frame: Immediately post-stenting optimization during the index percutaneous coronary intervention (PCI) procedure.
The minimal stent area (MSA) will be measured in square millimeters by intravascular ultrasound (IVUS) after final procedural optimization. The primary comparison will evaluate the MSA specifically at the exact site of the initial heaviest calcium burden to demonstrate the superiority of the Naviscore scoring balloon over standard non-compliant (NC) balloons.
Immediately post-stenting optimization during the index percutaneous coronary intervention (PCI) procedure.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Minimal Stent Area (MSA) Across the Entire Stented Segment
Time Frame: Immediately post-stenting optimization during the index percutaneous coronary intervention (PCI) procedure
The minimal stent area (MSA) in square millimeters measured across the entire length of the deployed segment using intravascular ultrasound (IVUS) pullbacks to evaluate overall stent expansion expansion
Immediately post-stenting optimization during the index percutaneous coronary intervention (PCI) procedure
Stent Eccentricity at the Site of the Minimal Stent Area
Time Frame: Immediately post-stenting optimization during the index percutaneous coronary intervention (PCI) procedure
Stent eccentricity index calculated as the ratio of the minimum stent diameter over the maximum stent diameter, measured via intravascular ultrasound (IVUS) at the exact cross-section of the minimal stent area segment
Immediately post-stenting optimization during the index percutaneous coronary intervention (PCI) procedure
Stent Eccentricity at the Initial Heaviest Calcium Burden Site
Time Frame: Immediately post-stenting optimization during the index percutaneous coronary intervention (PCI) procedure
Stent eccentricity index calculated as the ratio of the minimum stent diameter over the maximum stent diameter, measured via intravascular ultrasound (IVUS) specifically at the cross-section matching the initial heaviest baseline calcium plaque burden
Immediately post-stenting optimization during the index percutaneous coronary intervention (PCI) procedure
Device Success Rate
Time Frame: During the index percutaneous coronary intervention (PCI) procedure
Percentage of cases achieving successful delivery of the assigned pre-dilatation balloon, complete inflation with adequate lesion preparation, and the absolute absence of vessel rupture or advanced coronary perforation categorized by the Ellis classification
During the index percutaneous coronary intervention (PCI) procedure
Major Adverse Cardiac Events (MACE) Rate
Time Frame: At 1 and 12 months post-procedure
Percentage of participants experiencing Major Adverse Cardiac Events (MACE), defined as a composite clinical endpoint of myocardial infarction, stroke or transient ischemic attack, or cardiac death
At 1 and 12 months post-procedure
Target Lesion Failure (TLF)
Time Frame: At 1 and 12 months post-procedure
Percentage of participants experiencing Target Lesion Failure (TLF), defined as a composite of cardiac death, target-vessel myocardial infarction defined according to ARC-2 criteria, or clinically indicated Target Lesion Revascularization
At 1 and 12 months post-procedure
Target Vessel Failure (TVF)
Time Frame: At 1 and 12 months post-procedure
Defined as a composite of cardiac death, target-vessel myocardial infarction, or clinically indicated Target Vessel Revascularization (TVR).
At 1 and 12 months post-procedure
Clinically Indicated Target Lesion Revascularization (TLR)
Time Frame: At 1 and 12 months post-procedure
Percentage of participants requiring a repeat percutaneous coronary intervention (PCI) or coronary artery bypass graft surgery (CABG) driven by a recurrent narrowing inside the originally treated target lesion segment (including the stent and its five-millimeter proximal and distal borders), which is accompanied by clinical symptoms of ischemia or objective functional evidence of myocardial ischemia.
At 1 and 12 months post-procedure
Clinically Indicated Target Vessel Revascularization (TVR)
Time Frame: At 1 and 12 months post-procedure
Percentage of participants requiring any repeat percutaneous coronary intervention (PCI) or coronary artery bypass graft surgery (CABG) in any segment of the originally treated target vessel, driven by angiographic restenosis or disease progression, and accompanied by clinical symptoms of ischemia or objective functional evidence of myocardial ischemia.
At 1 and 12 months post-procedure
Procedural Success Rate
Time Frame: During the index percutaneous coronary intervention (PCI) procedure and until hospital discharge (up to 24 hours post-procedure).
Percentage of cases achieving Device Success (successful delivery of the assigned balloon and complete inflation with adequate lesion preparation) combined with a final residual stenosis of less than thirty percent as measured by quantitative coronary angiography (QCA) and a final Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow, without the occurrence of in-hospital Major Adverse Cardiac Events (MACE).
During the index percutaneous coronary intervention (PCI) procedure and until hospital discharge (up to 24 hours post-procedure).
Final Residual Stent Underexpansion
Time Frame: At the end of the index percutaneous coronary intervention (PCI) procedure (immediate post-stenting optimization).
Evaluation of the final residual underexpansion of the drug-eluting stent after deployment and high-pressure post-dilatation, measured in millimeters using motion-corrected X-ray stent visualization software (StentBoost or equivalent stent enhancement method) in two orthogonal views without contrast.
At the end of the index percutaneous coronary intervention (PCI) procedure (immediate post-stenting optimization).
Final Stent Diameter Stenosis
Time Frame: At the end of the index percutaneous coronary intervention (PCI) procedure.
The final percentage of stent diameter stenosis evaluated by quantitative coronary angiography (QCA) at the index procedure after final stent deployment and post-dilatation optimization.
At the end of the index percutaneous coronary intervention (PCI) procedure.
Rate of Procedural Complications
Time Frame: During the index percutaneous coronary intervention (PCI) procedure (immediate intra-procedural period).
The cumulative rate of procedure-related complications during the index procedure, defined as a composite of cardiac death, acute myocardial infarction, emergency coronary artery bypass graft surgery (CABG), coronary artery perforation (Ellis classification), and cardiac tamponade directly related to the use of the Naviscore scoring balloon or the regular non-compliant (NC) balloon.
During the index percutaneous coronary intervention (PCI) procedure (immediate intra-procedural period).
Procedural Cost-Effectiveness
Time Frame: During the index percutaneous coronary intervention (PCI) procedure.
Evaluation of the procedural cost-effectiveness of using the Naviscore scoring balloon compared to standard non-compliant (NC) balloons for calcified lesion preparation, calculated by factoring device costs, overall material utilisation during the intervention, procedure duration, and the need for bailout additional plaque-modification tools or complementary high-pressure devices.
During the index percutaneous coronary intervention (PCI) procedure.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Mons

Collaborators

iVascular S.L.U.

Investigators

  • Principal Investigator: Stéphane Carlier, MD, PhD, University of Mons
  • Principal Investigator: Antonio Serra

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

July 1, 2026

Primary Completion (Estimated)

June 1, 2027

Study Completion (Estimated)

June 1, 2028

Study Registration Dates

First Submitted

June 10, 2026

First Submitted That Met QC Criteria

June 10, 2026

First Posted (Actual)

June 16, 2026

Study Record Updates

Last Update Posted (Actual)

June 16, 2026

Last Update Submitted That Met QC Criteria

June 10, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 009 (Nahrain Medical Research Collective (NMRC))
  • Unrestricted grant (Other Grant/Funding Number: iVascular)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

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.

IPD Sharing Time Frame

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

IPD Sharing Access Criteria

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.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP
  • ICF

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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