Mitral Valve Repair is Preferred Over Replacement in Infective Endocarditis
When at all possible, mitral valve repair should be performed instead of mitral valve replacement in the setting of active infection because of the risk of infection of prosthetic materials 1, 2, 1.
The Evidence Strongly Favors Repair
The ACC/AHA guidelines explicitly state that repair should be prioritized "when at all possible" in active mitral valve endocarditis. This recommendation is driven by three critical factors that directly impact mortality and morbidity:
Why Repair is Superior
Lower mortality risk: The most recent high-quality evidence demonstrates that mitral valve repair is independently associated with significantly lower in-hospital mortality (4% vs 7%, p<0.001) and reduced risk of death even after risk adjustment (OR: 0.65,95% CI: 0.43-0.97) 3. A 16-year meta-analysis of over 4,000 patients confirms superior long-term survival with repair (HR: 1.41 for replacement, 95% CI: 1.30-1.53, p<0.001) 4.
Reduced infection risk: Prosthetic materials are inherently more susceptible to bacterial colonization and reinfection. Repair avoids introducing foreign material into an infected field, which is why guidelines emphasize this approach specifically "in the setting of active infection" 1, 2.
Better postoperative outcomes: Repair is associated with significantly lower rates of:
- Re-exploration for bleeding (6% vs 9%, p=0.019)
- Postoperative stroke (1% vs 3%, p=0.030)
- Postoperative dialysis requirement (5% vs 7%, p=0.016) 3
Lower recurrent endocarditis: The risk of IE recurrence is significantly reduced with repair (RR: 0.46, p=0.03) 4.
When Repair May Not Be Feasible
The decision between repair and replacement is ultimately determined by intraoperative valve characteristics, not by the severity of systemic infection or patient health status 5. Risk factors that may necessitate replacement include:
- Poor valve quality with extensive tissue destruction (OR 23.3 for requiring replacement)
- Large defects after debridement (OR 16.4)
- Heavy valve infection with extensive involvement (OR 3.7) 5
The Repair Strategy Matters
Limited resection is preferred over radical resection when feasible. A limited-resection strategy (removing only obviously infected tissue without extensive patch reconstruction) achieves:
- 84% repair rate vs 18% with radical resection (p<0.001)
- Comparable mortality and reinfection rates
- Similar reoperation rates despite higher repair rates 6
The European guidelines note that "surgery may be preferred if a procedure preserving the native valve is feasible" 7, reinforcing that repair should be attempted whenever technically possible.
Critical Caveat About Durability
While repair offers superior early and long-term survival, complex repair techniques using patches for extensive leaflet defects are associated with higher reoperation rates 5. However, even accounting for this, the overall survival benefit of repair outweighs the reoperation risk. The reoperation rate difference becomes non-significant in some studies after propensity matching 8, and when reoperations do occur, they don't negate the survival advantage 4.
The Bottom Line Algorithm
- Always attempt repair first if the valve anatomy permits after debridement
- Use limited resection technique when possible (remove infected tissue but avoid extensive patch reconstruction)
- Accept replacement only when:
- Valve tissue quality is too poor after debridement
- Defects are too large to reconstruct durably
- Heavy infection has destroyed valve architecture beyond repair
- Never delay surgery to attempt prolonged medical therapy if surgical indications exist—early surgery improves outcomes and increases likelihood of successful repair 1, 7
The contemporary trend unfortunately shows declining repair rates despite evidence supporting repair 8, suggesting this guideline recommendation needs stronger implementation in clinical practice.