Is a sternotomy (sternal incision) always necessary for mitral valve repair?

Mitral Valve Repair Does NOT Require Full Sternotomy

No, a full sternotomy is not necessary for mitral valve repair—multiple minimally invasive approaches are now well-established alternatives that offer significant advantages in recovery, pain, and blood loss without compromising safety or durability. 1

Available Surgical Approaches

Four distinct techniques have emerged as acceptable alternatives to full sternotomy for mitral valve repair 1:

1. Lower Hemisternotomy

• Involves a 6-8 cm vertical midline incision starting 2.5 cm below the angle of Louis (sternomanubrial junction) toward the xiphoid process 1
• The sternotomy extends into the right second intercostal space while keeping the manubrium intact 1
• Key advantage: allows direct aortic cannulation and cross-clamping 1
• Morbid obesity is a relative contraindication; reoperations are contraindicated due to difficulty exposing the aorta 1

2. Direct-Vision Right Minithoracotomy

• Uses peripheral cannulation (femoral vessels) rather than central cannulation 1
• Provides excellent exposure of the mitral valve, often equal to or better than sternotomy 1

3. Endoscopic Right Minithoracotomy

• Utilizes video assistance with long-shafted instruments 1
• Exposure is enhanced through endoscopy and proper working incision placement relative to the pulmonary hilum 1

4. Robotic-Assisted Right Minithoracotomy

• Involves 3-4 cm right minithoracotomy with robotic assistance 2
• Ideal for patients with isolated mitral valve disease, particularly posterior leaflet prolapse 2
• Requires high-volume centers (>140 mitral operations annually) and experienced surgeons (≥20 robotic cases/year) 2

Clinical Outcomes: Minimally Invasive vs. Sternotomy

Advantages of Minimally Invasive Approaches

Minimally invasive mitral valve surgery demonstrates clear benefits in multiple domains without compromising safety 3, 4, 5:

• Significantly less blood loss: 24-hour chest tube drainage 120 mL vs. 400 mL with sternotomy 3
• Reduced transfusion requirements: 15.7% vs. 40.6% with sternotomy 3
• Faster extubation: 6.2 hours vs. 10.4 hours with sternotomy 3
• Less postoperative pain: significantly lower pain scores at day 2 and weeks 1,3,6, and 12 4, 5
• Faster recovery: patients report significantly better recovery time composite scores 4
• Superior respiratory function: higher postoperative FEV1 and more patients extubated in operating room (18% vs. 5.7%) 5

Safety Profile

Mortality and major complications are equivalent between approaches 3, 4, 5:

• 30-day mortality: no significant difference (0.17-1.2% minimally invasive vs. 0.6-0.85% sternotomy) 3, 5
• Stroke, renal failure, myocardial infarction, and infection rates: similar between approaches 5
• Operative mortality for robotic MVR should be <1% 2

Trade-offs

Minimally invasive approaches require slightly longer operative times 3, 5:

• Cardiopulmonary bypass time: 99 minutes vs. 88 minutes with sternotomy 3
• Cross-clamp time: 65 minutes vs. 49 minutes with sternotomy 3
• However, full sternotomy—not bypass time—is the independent risk factor for transfusion, re-exploration for bleeding, and prolonged ventilation 3

Long-Term Durability

Minimally invasive approaches provide equivalent long-term outcomes 2, 3:

• Freedom from reoperation at 15-20 years: 95% 2
• Freedom from recurrent moderate-severe mitral regurgitation at 15-20 years: >80% 2
• No significant difference in survival curves or valve-related morbidity at mean 4.4-year follow-up 3

Important Caveats

When Sternotomy May Still Be Necessary

Certain anatomical and clinical factors may necessitate conversion to sternotomy 1:

• Significant aortic, iliac, or femoral disease preventing safe retrograde arterial perfusion 1
• Left ventricular ejection fraction <25% 1
• Severe right ventricular dysfunction 1
• Pulmonary artery pressure >70 mmHg 1
• Significant mitral annular calcification 1
• Unexpected extensive right chest adhesions 1
• Poor visualization or inadequate myocardial protection 1
• Extended cross-clamp time (>2 hours) or inadequate venous drainage 1

Learning Curve Considerations

A graduated training pathway is essential for safe implementation 2:

• Surgeons should complete preclinical training, clinical progression, and team development 2
• The entire surgical team requires training, including observation and proctoring 2
• Hospital volume is the single most critical determinant of success: centers performing >140 mitral operations annually achieve 77% repair rates vs. 48% at low-volume centers 2

Bottom Line

Minimally invasive mitral valve repair should be considered the preferred approach for appropriate candidates, offering superior recovery, less pain, reduced blood loss, and equivalent safety and durability compared to full sternotomy. 3, 4, 5 The choice of specific minimally invasive technique depends on patient anatomy, institutional expertise, and surgeon experience, but full sternotomy is no longer the default requirement for mitral valve repair.