# Aortic Root Replacement: Bentall, Valve-Sparing, and Ross Procedures

## Overview

Aortic root pathology — including aneurysm, dissection, endocarditis, and connective tissue disorders — often requires complete root replacement. The surgeon must choose among composite valve-graft replacement (Bentall), valve-sparing root replacement (David or Yacoub), and the Ross procedure (pulmonary autograft). Each approach has distinct indications, technical requirements, and long-term implications.

## Anatomy of the Aortic Root

### Components

The aortic root is a complex three-dimensional structure composed of several interrelated components. The **aortic annulus** is crown-shaped and lies at the base of the aortic valve. The **sinuses of Valsalva** are three dilated pouches (left, right, and noncoronary) that support the coronary ostia and create the space for leaflet opening. The **sinotubular junction (STJ)** marks the transition between the sinuses and the tubular ascending aorta. The **coronary ostia** arise from their respective sinuses, with the left coronary ostium in the left sinus above the commissure between the left and right sinuses, and the right coronary ostium in the right sinus. The **interleaflet triangles** are triangular fibrous zones between the leaflet nadirs and commissures.

### Dimensions

The normal aortic root diameter at the sinuses measures 3.0-3.5 cm, varying with body size. The STJ is slightly smaller than the sinuses, and the annulus is slightly smaller than the STJ. Root dilatation exceeding 4.5 cm generally warrants consideration for intervention.

## Bentall Procedure (Composite Root Replacement)

### Indications

The Bentall procedure is indicated for aortic root aneurysm with concomitant aortic valve pathology (stenosis or irreparable regurgitation), acute Type A dissection with root involvement or pre-existing root aneurysm, prosthetic valve endocarditis with root abscess (though homograft may be preferred), and connective tissue disorders with root dilatation requiring valve replacement.

### Technique (Modified Bentall/Button Technique)

The operation is performed through a sternotomy with CPB, aortic cross-clamp, and cardioplegia. The aorta is transected at the STJ, and the aortic valve and sinuses are excised. **Coronary button mobilization** involves creating circular buttons of aortic wall (1-2 cm diameter) around each coronary ostium. The annulus is sized and an appropriate valved conduit (mechanical or bioprosthetic valve pre-sewn to a Dacron graft) is selected. The conduit is sutured to the annulus with pledgeted mattress sutures as in standard AVR. The **coronary buttons are reimplanted** by creating openings in the graft at the appropriate locations and anastomosing each coronary button to the graft with running polypropylene suture. The distal anastomosis is completed to the ascending aorta (or arch if extended repair is needed), followed by de-airing and weaning from CPB.

### Outcomes

Operative mortality is 2-5% for elective cases and higher for emergency or dissection operations. Ten-year survival is 80-90%, with very low reoperation rates (less than 5% at 10 years). Coronary button complications (bleeding, kinking, stenosis) occur in 1-3%.

## Valve-Sparing Aortic Root Replacement

### Rationale

Valve-sparing root replacement preserves the native aortic valve, avoiding all prosthesis-related complications. No anticoagulation is required, and the native valve provides ideal hemodynamics. A growing body of evidence supports durable long-term results in selected patients, though the best outcomes are achieved at experienced centers with dedicated valve repair programs.

### Patient Selection

Ideal candidates include patients with aortic root aneurysm and normal or mildly prolapsing cusps, aortic regurgitation secondary to root dilatation (Type I mechanism), connective tissue disorders (Marfan, Loeys-Dietz) in younger patients, and bicuspid aortic valve with root dilatation and minimal cusp pathology. Contraindications include severe cusp calcification or retraction (irreparable valve), aortic stenosis, and (relatively) more than moderate cusp asymmetry in bicuspid valves.

### David Procedure (Reimplantation)

#### Technique

The sinuses are excised down to 2-3 mm from the annulus while preserving the coronary buttons. A Dacron graft is selected (a Valsalva graft with a bulging segment to recreate neo-sinuses, or a straight graft with sinus creation). Subannular sutures — horizontal mattress sutures placed below the nadir of each cusp — are brought through the base of the graft to fix the annulus inside the graft. The native valve is reimplanted inside the graft by suturing each commissure at the appropriate height. Coronary buttons are reimplanted as in the Bentall, and the distal aortic anastomosis is completed.

#### Key Advantages

The David procedure fixes the annular diameter, preventing future annular dilatation. It creates neo-sinuses to maintain near-normal leaflet dynamics. It is particularly well-suited for Marfan syndrome because it addresses the tendency toward annular dilatation.

### Yacoub Procedure (Remodeling)

#### Technique

In the Yacoub remodeling technique, the graft is tailored to create three tongues that replace the individual sinuses. Each tongue is sutured to the remaining aortic wall above the annulus. Critically, the annulus itself is not fixed within the graft — there are no subannular sutures. Coronary buttons are reimplanted as in the other procedures.

#### Key Differences from David

The Yacoub procedure does not stabilize the annulus, creating a risk of late annular re-dilatation and AR recurrence. However, it allows more physiologic leaflet motion because the sinuses are created directly. It may be combined with an external annuloplasty ring to address the annular limitation.

### Valve-Sparing Outcomes

Operative mortality is 1-3% in experienced centers. Ten-year freedom from more than moderate AR is 85-95% for the David procedure and 80-90% for the Yacoub. Ten-year freedom from reoperation is 90-95% for the David and 85-90% for the Yacoub. Results are heavily surgeon- and volume-dependent.

<image>Comparative surgical illustration of the David reimplantation versus Yacoub remodeling technique for valve-sparing aortic root replacement. The left panels (David) show: (A) the aortic root dissected down to the annulus with sinuses excised and coronary buttons mobilized, (B) subannular horizontal mattress sutures placed and brought through the base of a Dacron Valsalva graft, (C) the native valve suspended inside the graft at the commissural level, and (D) the completed repair with coronary buttons reimplanted. The right panels (Yacoub) show: (A) the same root preparation, (B) the Dacron graft tailored with three scalloped tongues, (C) each tongue sutured to the aortic wall remnant above the annulus to recreate individual sinuses, and (D) the completed repair. A comparison box highlights the key difference: David fixes the annulus (prevents dilatation); Yacoub does not.</image>

## Ross Procedure (Pulmonary Autograft)

### Concept

In the Ross procedure, the patient's native pulmonary valve (autograft) replaces the diseased aortic valve and root, and the pulmonary position is reconstructed with a homograft (cryopreserved pulmonary or aortic). This creates a living autograft in the aortic position with potential for growth and excellent hemodynamics.

### Indications

The Ross procedure is indicated for young patients (under 50-55 years) with aortic valve disease who desire to avoid anticoagulation and mechanical valves, children and adolescents with aortic valve disease (the autograft grows with the patient), active young adults and women of childbearing age, and patients with contraindications to anticoagulation.

### Contraindications

Connective tissue disorders (Marfan, Loeys-Dietz) are a contraindication because the autograft root will dilate. Other contraindications include significant pulmonary valve pathology (bicuspid pulmonary valve, rheumatic disease), active endocarditis (relative), severely dilated aortic root (greater than 28-30 mm annulus — autograft-annulus mismatch), and autoimmune or inflammatory diseases that may affect autograft durability.

### Technique

Through a sternotomy with CPB and aortic cross-clamp, the aortic valve and root are excised as in a Bentall procedure. The pulmonary autograft is then harvested by carefully excising the pulmonary root with 3-5 mm of RVOT muscle. During this step, the first septal perforator of the LAD (which runs close to the pulmonary root) must be identified and preserved, and injury to the membranous septum must be avoided. The autograft is reimplanted in the aortic position with a proximal suture line at the annulus, coronary button reimplantation, and a distal anastomosis. Some surgeons reinforce the autograft with an external support (Dacron wrap or mesh) to prevent dilatation. The RVOT is then reconstructed with a pulmonary homograft.

### Outcomes

Operative mortality is 1-3% in experienced centers, with excellent hemodynamics (no gradient, laminar flow, no anticoagulation). Twenty-year freedom from autograft reoperation is 80-90%. The main long-term concern is **neoaortic root dilatation**, which occurs in 10-30% of patients over 15-20 years and may lead to progressive neoaortic regurgitation; external reinforcement techniques aim to mitigate this. The pulmonary homograft may require replacement in 10-20% of patients at 15-20 years, especially in younger patients.

### The Ross Debate

Proponents emphasize the best hemodynamics available, freedom from anticoagulation, living tissue, superior quality of life, and survival equivalent to the age-matched population. Critics point out that the Ross procedure converts a one-valve disease to a two-valve disease, carries risk of neoaortic dilatation, depends on homograft durability, is technically complex, and is performed by a limited number of surgeons. The procedure is experiencing a resurgence with improved understanding of technique (root reinforcement) and patient selection.

<image>Surgical illustration of the Ross procedure showing the key steps. Panel A shows the native aortic root excised and the pulmonary autograft being harvested from the RVOT, with the relationship to the LAD first septal perforator labeled. Panel B shows the pulmonary autograft positioned in the aortic root with proximal anastomosis completed and coronary buttons being reimplanted. Panel C shows a pulmonary homograft being sutured into the RVOT position. Panel D shows the completed Ross operation with the autograft in the aortic position and the homograft in the pulmonary position, with external Dacron reinforcement around the autograft neo-root to prevent late dilatation.</image>

## Choosing Among Root Replacement Options

| Factor | Bentall | David | Ross |
|--------|---------|-------|------|
| Valve condition | Diseased/irreparable | Normal/repairable | Diseased aortic, normal pulmonary |
| Age range | Any | Any (best in < 65) | Young (< 50-55) |
| Anticoagulation | If mechanical | None | None |
| Durability | Excellent (mechanical) | Excellent if cusp quality is good | Excellent (autograft may dilate) |
| Complexity | Moderate | High | Very high |
| CTD suitability | Yes | Yes (David preferred) | No (dilatation risk) |
| Reintervention risk | Very low | Low-moderate | Moderate (two valves at risk) |

## Clinical Pearls

The Bentall procedure with the button technique is the workhorse of aortic root surgery — it is reliable, reproducible, and applicable to nearly all root pathologies. Valve-sparing root replacement (David) should be strongly considered in younger patients with root aneurysm and a structurally normal valve because it avoids all prosthesis-related complications. The David procedure is technically more complex than the Bentall but produces excellent long-term results in experienced hands, and surgeon volume matters significantly. The key difference between David and Yacoub is annular fixation: the David procedure fixes the annulus (preventing re-dilatation), making it preferable for connective tissue disorders. The Ross procedure offers the best hemodynamics and quality of life for young patients, but it requires dedicated expertise and creates a lifelong two-valve surveillance burden. External autograft reinforcement in the Ross procedure is increasingly used to prevent neoaortic root dilatation and may improve long-term durability. Connective tissue disorder patients should not undergo the Ross procedure because the autograft neo-root will dilate; the David reimplantation is the preferred valve-sparing option.

## References

- **David TE, David CM, Feindel CM, Manlhiot C.** Reimplantation of the aortic valve at 20 years. *J Thorac Cardiovasc Surg.* 2017;153(2):232-238.
- **Sievers HH, Stierle U, Charitos EI, et al.** A multicentre evaluation of the autograft procedure for young patients undergoing aortic valve replacement: update on the German Ross Registry. *Eur J Cardiothorac Surg.* 2016;49(1):212-218.
- **El-Hamamsy I, Eryigit Z, Stevens LM, et al.** Long-term outcomes after autograft versus homograft aortic root replacement in adults with aortic valve disease. *Lancet.* 2010;376(9740):524-531.
- **Ouzounian M, Rao V, Manlhiot C, et al.** Valve-sparing root replacement compared with composite valve graft procedures in patients with aortic root dilation. *J Am Coll Cardiol.* 2010;55(24):2708-2715.
- **Cohn LH, Adams DH.** *Cardiac Surgery in the Adult.* 5th ed. McGraw-Hill; 2017.