Towards a More Standardized Bicuspid Aortic Valve Repair: Rationale and Design of CONTOUR Trial - a Randomized Trial

University Hospital Augsburg

Status: Enrolling

Conditions: Bicuspid Aortic Valve (BAV); Aortic Regurgitation Disease

Treatments: Device: Internal HAART 200 annuloplasty device; Device: double external ring annuloplasty

Study type: Interventional

Funder types: Other

Identifiers

NCT06869954

23-0625

Details and patient eligibility

About

Background: Between one-third and one-half of patients with bicuspid aortic valve (BAV) disease develop significant aortic regurgitation (AR) at a young age, leading to cardiomyopathy and heart failure. Aortic valve repair is an evolving and still underused strategy in BAV patients with AR. The lack of sufficient standardization remains the main limitation of current repair techniques, resulting in an increased risk of AR recurrence and reoperation. The most controversial issue is the stabilization of the BAV annulus. The CONTOUR trial aims to compare two different BAV annuloplasty concepts in a prospective randomized study.

Methods: CONTOUR is a multicenter, randomized controlled trial designed to enroll 100 consecutive BAV patients with AR across four sites in Germany. BAV AR patients with an asymmetric configuration and without concomitant root aneurysm will be randomized 1:1 to undergo aortic valve repair using an internal HAART 200 annuloplasty device (i.e., INTERNAL group) (n=50) or external annuloplasty (i.e., double external ring annuloplasty) in the EXTERNAL group (n=50). 4D flow MRI will be performed preoperatively (t1), postoperatively at discharge (t2), and at 1-year follow-up (t3) for rater-blinded assessment of hemodynamic profiles (i.e., flow eccentricity) and regurgitation fraction at the MRI core-lab. Two hierarchically ordered primary endpoints will be considered: (1) postoperative reduction of flow eccentricity at hospital discharge and (2) regurgitation fraction (%) at 1-year follow-up.

Discussion: The CONTOUR trial is designed to test the hypothesis that an internal annuloplasty device, creating a completely symmetric post-repair BAV geometry, achieves superior aortic valve repair outcomes compared to external annuloplasty. If our hypothesis is confirmed, our study will significantly influence aortic valve repair practice and contribute to the refinement of guideline recommendations in the management of BAV patients with AR.

Enrollment: 100 estimated patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

1. Presence of fused BAV phenotype with an asymmetric configuration (commissural orientation < 170 degree) [14]
2. Severe aortic regurgitation (vena contracta (vc) > 6mm and/or pressure half-time (PHT) < 200 ms and/or effective regurgitant orifice area (EROA) > 30 mm2 and/or regurgitant volume (RV) > 60 ml/beat and/or left ventricular end-systolic diameter (LVESD) > 50mm (or indexed LVESD > 20mm/m2 BSA) and/or regurgitation fraction (RF) in cardiothoracic MRI > 40%) (at least one parameter is required) [15]
3. Isolated aortic valve surgery or concomitant procedure (including CABG and/or mitral/tricuspid valve surgery and/or ascending aortic surgery)
4. Willingness to participate and written informed consent
5. Age at surgery > 18 years

Exclusion criteria

1. Moderate/severe BAV stenosis (pmean > 20mmHg)
2. Moderate/severe BAV cusp calcifications extending beyond the raphe region and/or necessitating patch implantation (deemed irreparable based on preoperative TOE (as by decision of the operating surgeon)
3. Concomitant aortic root aneurysm > 45mm requiring simultaneous aortic root surgery [16]
4. Acute/subacute BAV endocarditis
5. Contraindication to MRI

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Single Blind

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100 participants in 2 patient groups

INTERNAL Group

Active Comparator group

Description:

For the INTERNAL group, the HAART 200 internal annuloplasty ring (CorCym, London, UK), specifically designed for BAV morphology, will be used for all patients. Intraoperative sizing for the internal ring is based on the geometric orientation and size of the non-fused cusp. A standard ball sizer is used for the measurement of the non-fused cusp to assess commissural orientation and surface area of the non-fused cusp. Sizing typically results in values of 23mm or 25mm, with other sizes being very rare. Both commissural posts of the internal annuloplasty ring are fixed using two subcommissural sutures \[10\]. A modified technique for placement of transannular looping sutures will be used to secure the internal ring in the subannular position, as recently published \[21\]. Cusp maneuvers (i.e., shaving, thinning of the raphe, central plication sutures) will be performed to achieve an effective height of 8-10 mm. When indicated (i.e., for ascending aortic diameter \> 45mm or aiming to achieve t

Treatment:

Device: Internal HAART 200 annuloplasty device

EXTERNAL group

Active Comparator group

Description:

For the EXTERNAL group, all study patients will undergo double external Dacron ring annuloplasty by simultaneous stabilization of the basal virtual ring and the STJ \[22\]. The surgical technique of double external annuloplasty, detailed by the Lansac group \[22\], involves aortic annulus sizing with a Hegar dilator to select the sizes of the external subannular annuloplasty ring and STJ ring (same size). After deep dissection of the aortic root, 6-7 2-0 pledgeted U sutures are placed circumferentially at the level of the virtual basal ring for external subannular ring implantation. Cusp maneuvers are performed similar to those in the INTERNAL group. STJ stabilization is achieved using an external STJ ring or ascending aortic replacement with a vascular tube graft (e.g., in cases with a high offspring of the right coronary artery). Treatment of the tubular ascending aorta is identical to the INTERNAL group.

Treatment:

Device: double external ring annuloplasty