Mitral endocarditis: patchless repair rivals replacement

Active mitral endocarditis: is limited resection without a patch a safe alternative?

Surgical treatment of infective endocarditis (IE) on native mitral valve remains a high-risk procedure where every millimeter of preserved tissue counts. While international guidelines favor valve repair over replacement, conventional techniques generally require radical resection of infected tissues combined with complex prosthetic patch reconstruction. However, concerns regarding the durability of patch materials hinder the widespread adoption of this approach, limiting the repair rate to approximately 25% in current practice.

Cette étude rétrospective monocentrique évalue une stratégie chirurgicale alternative : la résection limitée du tissu infecté avec fermeture directe, sans recours au patch (technique non-patch). L'objectif est de comparer les résultats cliniques à long terme (5 ans) de cette technique de préservation tissulaire (n=75) par rapport au remplacement valvulaire mitral après résection radicale (n=53), chez des patients présentant une EI native active. L'hypothèse testée est qu'une résection moins agressive pourrait augmenter la faisabilité de la réparation sans pour autant accroître le risque de récidive infectieuse ou de réopération, offrant ainsi une alternative viable aux techniques de reconstruction prothétique plus lourdes.

Study methodology

This retrospective monocentric study was conducted in a tertiary referral hospital between January 2016 and December 2021. The objective was to compare the long-term clinical outcomes of a limited resection strategy without patch versus mitral valve replacement (MVR) after radical resection in patients with active infective endocarditis.

• Study population: The sample included 128 patients with defined active infective endocarditis on native mitral valve (modified Duke criteria).
• Experimental groups:
  • Repair Group (n = 75): Limited resection of infected tissue with minimal margins relative to adjacent healthy tissue.
  • Replacement Group (n = 53): Radical resection of all infected tissue followed by valve replacement with a prosthesis.
• Surgical protocol (repair): After removal of the vegetations, perforations and defects were repaired by direct suture using nylon monofilament (Cardionyl®). Complementary techniques of chordal transfer or replacement were used if necessary. The procedure was completed by the placement of a flexible annuloplasty ring.
• Analysis and judgment criteria: The primary evaluation criteria over a 5-year follow-up were overall mortality, the incidence of endocarditis recurrence, and the reoperation rate. The Cox proportional hazards model was used to identify predictors of mortality and adverse events.

Results: Comparable survival despite opposing surgical approaches

The study included 128 consecutive patients with active infective endocarditis (IE) on a native mitral valve. Among them, 75 underwent repair by limited resection without a patch, while 53 underwent valve replacement after radical resection. Five-year follow-up was completed for 96% of the cohort (100% in the repair group versus 91% in the replacement group, p = 0.01).

In the short term, 30-day mortality was 16% for the repair group versus 25% for the replacement group. At the five-year mark, the data do not show statistical superiority of one strategy over the other regarding overall survival.

*Note: The reoperation case in the replacement group was related to a paravalvular leak.

Prognostic factors and microbiology

Multivariate analysis using the Cox model reveals that the surgical strategy (repair vs. replacement) is not independently associated with mortality or adverse events. In contrast, microbiological etiology emerges as the determining factor for the prognosis.

• Staphylococcal endocarditis: It constitutes a major predictor of overall mortality (HR: 2.2; 95% CI [1.3–3.7]) and composite adverse events including death, recurrence, and reoperation (HR: 2.2; 95% CI [1.0–4.9]).
• Surgical technique: In the repair group, direct closure of the perforations using nylon monofilament and the use of flexible annuloplasty rings avoided the need for prosthetic patches, whose durability is often questioned in infected environments.

Although the recurrence rate was numerically higher in the limited resection group, this trend did not significantly impact long-term survival compared to a radical approach. The aggressiveness of the germ, particularly staphylococcus, remains the predominant clinical challenge, regardless of the technical choice.

Towards an extension of mitral plasticity criteria

This monocentric study suggests that a limited resection strategy without a patch is technically viable for active native mitral endocarditis. With a repair rate of 58.5% within this cohort, this approach significantly exceeds the 25% usually reported in the literature, without significantly increasing 5-year mortality (43% vs 52% for replacement, p = 0.31). The clinical interest is direct: by dispensing with prosthetic patches, whose durability is often questionable, the surgeon simplifies the reconstruction and preserves the valvular architecture.

However, the practitioner must weigh this gain in repairability against the risk of recurrence. The repair group recorded 6 cases of reinfection compared to only one in the replacement group. Although the surgical strategy is not statistically correlated with an increase in adverse events in the Cox model, this result emphasizes that "limited" resection must never sacrifice the quality of the initial debridement. The study primarily identifies staphylococcal endocarditis as the true arbiter of prognosis, being a powerful predictor of mortality (HR: 2.2) and adverse events (HR: 2.2).

The study's limitations, notably its retrospective nature and selection bias (repaired patients were younger, 60 vs 65 years, and presented a lower EuroSCORE II, 3.22 vs 5.16), suggest selective application. Nevertheless, for non-staphylococcal cases, the patchless technique appears to be a solid alternative to avoid complications inherent to prostheses.

Summary of results

This retrospective study of 128 patients demonstrates that limited resection without a patch is a viable alternative to replacement, with a 5-year mortality rate of 43% compared to 52% (p = 0.31). While overall survival is comparable, Staphylococcus is identified as a major predictor of mortality (HR: 2.2). However, a higher incidence of recurrence (6 cases vs 1) and reoperations (5 cases vs 1) was noted in the repair group.

In concrete terms, for the practitioner:

• Promote valve preservation: Limited resection without prosthetic material is a reliable surgical strategy to increase repairability, particularly effective in non-staphylococcal cases.
• Microbiological alert: Be particularly vigilant against Staphylococcus aureus; its biological aggressiveness remains an independent risk factor (HR 2.2) that surgical technique alone is not sufficient to neutralize.
• Postoperative monitoring: Although survival is not impacted, plan for rigorous clinical follow-up, as the risk of infectious recurrence is numerically higher after repair without a patch.

Technical lexicon of the study

Limited resection: Surgical approach targeting the removal of vegetations and macroscopically infected tissues with minimal margins. This strategy aims to preserve tissue capital to facilitate repair rather than replacement.

Non-patch technique: Mitral leaflet reconstruction procedure using direct suture (nylon monofilament) of perforations or resection areas. It eliminates potential complications related to the durability of prosthetic materials by avoiding patch plasty.

Staphylococcal endocarditis: Valvular infection by Staphylococcus spp., identified in this study as the main independent predictor of mortality (HR: 2.2) and adverse events, regardless of the type of surgery.

Flexible band annuloplasty: Final stage of mitral repair using a flexible band secured by braided polyester sutures without "pledgets". It stabilizes the annulus to ensure the durability of valvular coaptation.

Modified Duke criteria: International diagnostic standard used in the study to confirm the diagnosis of active infective endocarditis before patient inclusion.

Adverse event (composite endpoint): Analysis endpoint combining death, recurrence of endocarditis, and the need for mitral reoperation during the five-year follow-up.

Information intended for healthcare professionals. This content may contain errors or truncated summaries. We recommend always verifying with the original source article. Delynov disclaims all responsibility regarding the use of this information. This document is not intended for patients or the general public.