What are the indications, pre‑operative evaluation, operative technique, and postoperative management for a modified Bentall procedure in an adult patient with an aortic root aneurysm larger than 5 cm and a diseased aortic valve?

Modified Bentall Procedure

The modified Bentall procedure is a composite valve-graft replacement technique that replaces the aortic root, aortic valve, and ascending aorta with reimplantation of the coronary arteries using a "button technique," indicated primarily for patients with aortic root aneurysms ≥5.5 cm combined with aortic valve disease. 1

Indications

Primary Indications

• Aortic root or ascending aortic diameter ≥5.5 cm with concurrent aortic valve disease (stenosis or regurgitation) 1, 2
• Aortic root aneurysm with severe aortic valve regurgitation requiring valve replacement 1

Earlier Intervention (5.0-5.5 cm) is Reasonable When:

• Rapid aortic growth ≥0.3-0.5 cm per year 1, 2
• Family history of aortic dissection 1, 2
• Bicuspid aortic valve (BAV) patients undergoing concomitant aortic valve replacement with aortic diameter ≥4.5 cm 2
• Aortic size index: Cross-sectional area (cm²) divided by height (m) ≥10 cm²/m 1
• Marfan syndrome or other connective tissue disorders 1
• Desire for pregnancy 1

Specific Populations

• Marfan syndrome: Threshold of 5.0 cm is reasonable given increased dissection risk 1
• Bicuspid aortic valve: 5.5 cm threshold, or 4.5 cm if concurrent valve surgery needed 2
• Acute Type A dissection involving the aortic root with valve involvement 3

Pre-operative Evaluation

Imaging Requirements

• Transthoracic echocardiography (TTE) to assess:

  • Aortic root dimensions at sinuses of Valsalva
  • Ascending aorta diameter
  • Aortic valve morphology and function (stenosis vs regurgitation severity)
  • Left ventricular function

• CT angiography or MRI from aortic arch to iliac arteries to:

  • Precisely measure maximal aortic dimensions
  • Evaluate extent of aneurysmal disease
  • Assess coronary ostia anatomy
  • Rule out distal aortic involvement
  • Plan surgical approach

Risk Assessment

• Evaluate for connective tissue disorders (Marfan, Loeys-Dietz, BAV syndrome)
• Assess surgical risk and comorbidities
• Multidisciplinary Aortic Team evaluation at a Comprehensive Valve Center is recommended for optimal outcomes 1, 2

Valve-Sparing vs Composite Graft Decision

• Consider valve-sparing root reimplantation (David procedure) if:

  • Aortic valve leaflets are structurally normal
  • Minimal or no aortic regurgitation
  • Patient desires to avoid anticoagulation
  • Performed at experienced center 1, 4

• Choose modified Bentall (composite graft) if:

  • Significant aortic valve disease (stenosis or severe regurgitation)
  • Abnormal valve leaflet tissue
  • Endocarditis 5
  • Most reliable option for diseased valves 1

Operative Technique

The Button Bentall Modification

The button technique is the current standard modification, preferred over the original Bentall 3, 5, 6:

1. Median sternotomy with cardiopulmonary bypass and cardiac arrest 6

2. Aortic root excision:

   • Remove diseased aortic root and valve
   • Create full-thickness "buttons" of aortic wall surrounding each coronary ostium (preserving 2-3mm rim of aortic tissue around ostia) 6, 7
   • This avoids mobilization and tension on coronary arteries 7

3. Composite graft implantation:

   • Use commercially available composite graft (prosthetic valve sewn to Dacron tube) or self-assembled graft 5
   • Mechanical valve (St. Jude Medical or similar) is traditional choice 7
   • Bioprosthetic valve is alternative for patients who cannot tolerate anticoagulation 1
   • Suture graft to left ventricular outflow tract proximally 1, 6

4. Coronary reimplantation:

   • Create openings in the Dacron graft at appropriate positions
   • Suture coronary ostia buttons directly to graft openings 6, 7
   • Minimal mobilization of coronary ostia reduces bleeding and pseudoaneurysm risk 7

5. Distal anastomosis:

   • Attach graft to ascending aorta distally
   • Replace entire ascending aorta if dilated 1
   • Keep tubular aorta minimally changed to reduce complications 7

Technical Advantages of Button Technique

• Reduced operative time compared to original Bentall 7
• Improved hemostasis with less postoperative bleeding (mean 450±105 mL) 7
• Lower risk of coronary pseudoaneurysm formation 3, 7
• Excellent long-term durability 5, 7

Postoperative Management

Immediate Postoperative Period

• ICU monitoring: Most patients (60%) discharge from ICU on postoperative day 1,90% by day 2 7
• Hospital stay: Average 5±2 days 7
• Monitor for bleeding (primary early complication concern)
• Assess for hemodynamic or respiratory complications

Anticoagulation (for Mechanical Valves)

• Initiate warfarin with target INR 2.5-3.5 (mechanical aortic valve)
• Bridge with heparin until therapeutic INR achieved
• Lifelong anticoagulation required for mechanical valves 1

Surveillance Imaging

• Baseline postoperative imaging with TTE before discharge

• Annual TTE surveillance to assess:

  • Prosthetic valve function
  • Residual aortic dimensions
  • Development of paravalvular leak

• CT or MRI surveillance of remaining aorta:

  • Especially important in connective tissue disorders
  • Monitor for progressive dilation of distal aorta 1

Long-term Monitoring

• Aortic valve-related complications: 3.6% per patient-year 3
• Reoperation risk: 2.7-4.1% per patient-year depending on technique 3
• 5-year actuarial survival: 79-97% 3, 7
• 5-year reoperation-free survival: 72.6-87% 3, 5

Common Pitfalls to Avoid

• Inadequate distal aortic assessment: The aorta may continue to dilate after root replacement, particularly in Marfan syndrome and BAV patients—annual surveillance is mandatory 2
• Valve-sparing in diseased valves: Do not attempt valve-sparing procedures when significant valve pathology exists; durability concerns include 7% developing moderate AR at 1 year in Marfan patients 1
• Underestimating bleeding risk: The button technique significantly reduces this compared to original Bentall, but meticulous hemostasis remains critical 7
• Inadequate anticoagulation education: Patients with mechanical valves require lifelong warfarin and comprehensive education about bleeding/thrombosis risks

Hospital Mortality and Outcomes

• Overall hospital mortality: 2.7-5% 3, 5
• Higher mortality with acute dissection, rupture, or emergency presentation 3
• Excellent long-term survival when performed electively at experienced centers 5, 7