Comparative Research of Y-Incision vs. Standard Techniques for Aortic Root EnLargement (CRYSTAL)

Comparative Analysis of Standard Surgical Techniques vs. "Y Incision" Technique for Aortic Root Enlargement in Patients With Small Aortic Annulus Undergoing Aortic Valve Replacement: A Randomized Open-Label Controlled Trial (CRYSTAL Trial - Comparative Research of Y-Incision vs. Standard Techniques for Aortic Root EnLargement)

Abstract Background: Aortic valve replacement (AVR) is crucial for patients with severe aortic valve disease. However, managing those with a small aortic annulus (SAA, i.e., annulus diameter < 22 mm) is challenging because implanting a small prosthesis can result in patient-prosthesis mismatch (PPM), suboptimal hemodynamic outcomes, and reduced long-term survival. Traditional surgical techniques for aortic root enlargement (ARE), such as the Nicks and Manougian procedures, have significant limitations, typically allowing enlargement of only one to two prosthesis sizes and involving complex reconstructive procedures. The novel "Y incision" technique by Bo Yang offers a promising alternative, allowing implantation of valves up to five sizes larger than the native annulus, but it lacks comprehensive comparative data on its safety, efficacy, and functional outcomes.

Aim: This study aims to compare the safety outcomes, hemodynamic performance, and functional capacity of the "Y incision" technique versus standard surgical enlargement techniques in patients with a small aortic annulus undergoing AVR, with particular emphasis on objective functional assessment using cardiopulmonary exercise testing (CPET).

Methods: This prospective, randomized, controlled superiority trial will enroll patients with aortic valve disease and a small aortic annulus where conventional AVR is expected to result in moderate or severe PPM. Patients will be randomized 1:1 to either the standard surgical technique group or the "Y incision" technique group. Based on preliminary results and power calculations using the Win Ratio methodology, the sample size is set at 90 patients (45 in each group) to account for potential dropouts.

Primary Endpoint: Hierarchical composite endpoint analyzed using Win Ratio methodology, including (in order of priority): all-cause mortality, stroke, myocardial infarction, total hospitalization rate, moderate or severe PPM, exercise-induced valve dysfunction, and functional improvement at specified time points through 12 months.

Secondary Endpoints: Safety outcomes including intraoperative and 30-day complications, long-term anatomical complications, hemodynamic parameters assessed by echocardiography, functional outcomes measured by 6-minute walk distance and CPET (including peak VO₂), quality of life assessed using KCCQ questionnaire, and prosthetic valve-related outcomes at 3, 6, and 12 months post-surgery.

Conclusion: By providing robust, randomized controlled data with objective functional capacity assessment, this study aims to fill current gaps in knowledge regarding the long-term outcomes, safety profile, and functional benefits of the "Y incision" technique compared to standard surgical methods, potentially establishing evidence-based guidance for managing patients with a small aortic annulus undergoing AVR.

Study Overview

• Status: Recruiting
• Conditions: Severe Aortic Valve Disease; Small Aortic Annulus; Aortic Valve Replacement (AVR)
• Intervention / Treatment: Procedure: Y incision Technique (YIT); Procedure: Standard surgical enlargement techniques

• Study Type: Interventional
• Enrollment (Estimated): 90
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Nadav Willner, MD; Phone Number: +972-50-8845456; Email: n_willner@rmc.gov.il

Study Locations

• Israel
  • Haifa, Israel, 210961
    • Recruiting
    • Rambam Health Care Campus
    • Contact: Nadav Willner, MD; Phone Number: +972-50-8845456; Email: n_willner@rmc.gov.il

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Adults aged 18-80 years.
• Patients must have signed and dated an ICF in accordance with regulatory and institutional guidelines before any protocol-related procedures and must be willing and able to comply with scheduled visits.
• Diagnosed with aortic valve disease requiring aortic valve replacement.
• Patients with small aortic annulus relative to body size where conventional AVR result in moderate or severe PPM (defined as cases where the largest prosthesis that can be implanted in the native annulus would provide a predicted iEOA ≤0.85 cm²/m² for BMI <30, or ≤0.70 cm²/m² for BMI ≥30), based on manufacturer specifications and patient BSA).
• Suitable candidates for surgery as determined by the heart team.

Exclusion Criteria:

1. Patients for whom conventional AVR without root enlargement is not expected to result in patient-prosthesis mismatch.
2. Prior cardiac surgery.
3. Severe concomitant valvular disease requiring additional procedures.
4. Active endocarditis.
5. Severe chronic lung disease
6. Pre-existing lower limb deficits or any other medical comorbidities that interfere significantly with gait or the ability to perform exercise testing on a bicycle ergometer
7. Severe left ventricular dysfunction (LVEF < 30%).
8. Contraindications to surgery.
9. Concurrent active treatment in another clinical trial

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Y-Incision Technique for Aortic Root Enlargement; The novel "Y incision" technique by Bo Yang allows implantation of valves up to five sizes larger than the native annulus	Procedure: Y incision Technique (YIT); A "Y"-shaped incision is made from the aortotomy, extending through the left coronary-noncoronary commissure into the aortomitral curtain. Thereafter, a Hemashield patch is sewn to the aortomitral curtain and the undermined aortic annulus, creating a larger space, and the bioprosthetic valve is placed and secured. Finally, the modified aortotomy is closed using the roof technique for better hemostasis and to enlarge the sinotubular junction and proximal ascending aorta. This technique allows the implantation of a valve up to five sizes larger than the native annulus.
Active Comparator: Standard Techniques for Aortic Root Enlargement; Traditional surgical techniques for aortic root enlargement (ARE), such as the Nicks and Manougian procedures, allow enlargement of only one to two prosthesis sizes and involve complex reconstructive procedures	Procedure: Standard surgical enlargement techniques; Traditional approaches include aortic root enlargement procedures such as the Nicks, Manougian, and Konno techniques; these procedures aim to widen the annulus and accommodate a larger prosthetic valve, thereby reducing the risk of PPM.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Hierarchical composite of clinical and functional outcomes (Win Ratio)	A composite hierarchical endpoint analyzed using the Win Ratio methodology. Pairs of patients (one from each study arm) are compared based on a prioritized sequence of outcomes. The hierarchy is: 1. Time to all-cause mortality; 2. Incidence of stroke; 3. Incidence of myocardial infarction; 4. Frequency of total hospitalizations; 5. Presence of moderate/severe Prosthesis-Patient Mismatch (PPM); 6. Exercise-induced valve dysfunction; and 7. Improvement in functional status (defined as ≥1 NYHA class improvement). A "win" is assigned to the patient with the better outcome at each step. Win Ratio - The ratio of the total number of wins in the intervention group to the total number of wins in the control group.	At specified time points through 12 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of Major Adverse Events (MAE) through 12 months.	Number of participants experiencing intraoperative and 30-day complications, and long-term anatomical complications (including valve thrombosis or migration). Unit of Measure: Number of participants.	Up to 12 months.
Change in Hemodynamic Parameters (Mean Pressure Gradient).	Assessment of the prosthetic valve mean pressure gradient as measured by transthoracic echocardiography. Unit of Measure: mmHg.	Baseline, 3, 6, and 12 months.
Change in 6-Minute Walk Distance (6MWD).	Change from baseline in the distance walked during a 6-minute period. Unit of Measure: Meters.	Baseline and 12 months.
Change in Quality of Life (KCCQ-12 Score).	Change in the Kansas City Cardiomyopathy Questionnaire (KCCQ-12) overall summary score. Scores range from 0 to 100, where higher scores represent better health status. Unit of Measure: Points on a scale.	Baseline, 3, 6, and 12 months.
Change in Peak Oxygen Consumption (Peak VO2)	Peak VO2 attained during Cardiopulmonary Exercise Testing (CPET) using a standardized ramp protocol on a cycle ergometer or treadmill. Unit of Measure: mL/kg/min	Baseline and 12 months post-surgery.
Incidence of Prosthetic Valve-Related Complications	Number of participants experiencing specific valve-related adverse events, including prosthetic valve thrombosis, device migration, endocarditis, or structural valve deterioration (SVD) as defined by VARC-3 criteria. Unit of Measure: Number of participants	3, 6, and 12 months post-surgery.
Incidence of Early Postoperative Complications (30 Days)	A composite of safety events occurring within the early postoperative period, including major bleeding (BARC type 3 or 5), acute kidney injury (Stage 2 or 3), and new-onset permanent atrial fibrillation. Unit of Measure: Number of participants	Within 30 days post-surgery.
Change in Effective Orifice Area (EOA)	The Effective Orifice Area of the prosthetic valve calculated via the continuity equation using transthoracic echocardiography (TTE) measurements. Unit of Measure: cm^2	Baseline, 3, 6, and 12 months post-surgery.
Change in NYHA Functional Classification	Assessment of heart failure symptoms according to the New York Heart Association (NYHA) Functional Classification. Scores range from Class I (no symptoms) to Class IV (severe symptoms). Unit of Measure: NYHA Class (I, II, III, or IV)	Baseline, 3, 6, and 12 months post-surgery.

Collaborators and Investigators

• Sponsor: willner nadav MD

Study record dates

Study Major Dates

• Study Start (Actual): January 4, 2026
• Primary Completion (Estimated): January 1, 2028
• Study Completion (Estimated): January 1, 2028

Study Registration Dates

• First Submitted: January 8, 2026
• First Submitted That Met QC Criteria: January 18, 2026
• First Posted (Actual): January 26, 2026

Study Record Updates

• Last Update Posted (Actual): January 26, 2026
• Last Update Submitted That Met QC Criteria: January 18, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: AVR; Aortic Root Enlargement; Small Aortic Annulus; Y Incision
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Heart Diseases; Heart Valve Diseases; Aortic Valve Disease
• Other Study ID Numbers: 0337-25-RMB

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: Undecided

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No