Calcified mitral annulus: securing the prosthesis with a pericardial patch

Surgical challenge of extensive MAC: the endoscopic approach with pericardial patch

Extensive mitral annular calcification (MAC) represents one of the most complex technical challenges in valvular surgery, burdened by high operative morbidity and mortality. The risks of atrioventricular rupture, circumflex artery injury, and prosthetic dehiscence often require complex strategies, even when transcatheter solutions are not feasible. This case study reports the management of an elderly female patient presenting with symptomatic severe mitral regurgitation on extensive circumferential MAC, with restrictive calcified leaflets.

The objective of this presentation is to describe an endoscopic mitral valve replacement (MVR) technique via a right mini-thoracotomy. The procedure relies on the use of an endoaortic balloon for clamping and the implantation of a bioprosthesis secured by an automatic knotting device (CorKnot). The originality lies in the addition of a bovine pericardial patch sutured to the posterior part of the prosthetic ring.

The clinical hypothesis tested by the authors, Orlandi et al., is that this "posterior skirt" technique reinforces the calcified posterior ring after limited debridement, thereby drastically reducing the risk of paravalvular leakage, even in cases where transcatheter valve implantation was excluded due to annular dimensions.

Study design and subject

This clinical case report details an endoscopic mitral valve replacement procedure in an elderly female patient. She presented with severe symptomatic mitral regurgitation associated with extensive circumferential mitral annular calcification (MAC), with calcified valve leaflets and preserved left ventricular systolic function.

Operating protocol and surgical technique

The preferred approach was an endoscopic right minithoracotomy under femoro-femoral cardiopulmonary bypass. Cardiac arrest was induced by cardioplegia via an endoaortic balloon. The procedure followed these steps:

• Excision of the native valve and limited debridement of annular calcifications.
• Implantation of a mitral bioprosthesis fixed with braided sutures with pledgets.
• Use of the CorKnot automatic device to secure suture knots.
• Application of the posterior "skirt" technique: a bovine pericardium patch was sutured to the posterior part of the prosthetic ring to reinforce the calcified mitral ring.

Analysis of results

The effectiveness of the technique and the tightness of the prosthesis were evaluated by postoperative echocardiography, specifically aiming to detect potential paravalvular leaks or ventricular dysfunction induced by the complex procedure on a calcified annulus.

Clinical results and observations

L'issue clinique de cette intervention endoscopique chez une patiente âgée présentant une calcification annulaire mitrale (MAC) circonférentielle exhaustive montre des résultats probants. L'échocardiographie postopératoire a permis de valider l'efficacité de la technique de la « jupe » de péricarde bovin pour sécuriser l'étanchéité prothétique.

• Imaging: Echocardiographic monitoring confirms the absence of major complications (such as dehiscence or atrioventricular rupture) despite the limited debridement of calcifications.
• Hemodynamics: Ventricular systolic function remained stable compared to preoperative data.

Note: As this is a case report, no p-value or statistical comparison is reported in the source.

Clinical analysis and technical relevance

The results of this case demonstrate that the endoscopic approach is not incompatible with the management of severe MAC. The use of the bovine pericardial patch as a posterior "skirt" proves to be clinically decisive: it allows for the compensation of annular irregularities after a voluntarily limited debridement, thus minimizing the traumatic risk to the atrioventricular groove while ensuring periprosthetic sealing.

Compared to current therapeutic options, this case highlights a major limitation of transcatheter mitral valve implantation (TMVI): the frequent mismatch between the annulus size and available devices. Where transcatheter fails for anatomical reasons, endoscopic surgery offers reconstruction flexibility thanks to the pericardial patch.

However, the limitations of this study lie in its unique nature (n=1). Although the immediate result is excellent, the lack of long-term follow-up does not allow for a conclusion on the durability of this pericardium-calcified ring interface or on the risk of secondary calcification of the patch itself.

Summary of results

This endoscopic approach demonstrates that limited calcium debridement, combined with the addition of a bovine pericardial "skirt", allows for stable implantation despite circumferential annular calcification. Postoperative results confirm trivial paravalvular leakage and preserved systolic ventricular function, validating this strategic compromise in the face of risks of atrioventricular rupture.

In practical terms, for the practitioner:

• Prioritize caution: limited debridement is preferable to aggressive resection to avoid fatal complications such as atrioventricular rupture or circumflex artery injury.
• Bet on the patch: adding a pericardium strip to the posterior part of the prosthetic collar compensates for ring irregularities and ensures sealing.
• Optimize fixation: the systematic use of pledgets and an automatic knotting device (CorKnot) ensures the secure anchoring of the bioprosthesis on a complex calcium support.

Technical lexicon of the procedure

Mitral Annular Calcification (MAC): Extensive calcium deposit at the level of the mitral annulus, significantly increasing the operative risks of atrioventricular rupture and periprosthetic leak.

Right minithoracotomy: Minimally invasive surgical approach used for endoscopic access, avoiding conventional sternotomy.

Endoaortic balloon: Device used endovascularly for aortic occlusion and cardioplegia administration, allowing cardiac arrest in a minimally invasive mode.

Posterior skirt technique: Reinforcement method consisting of suturing a bovine pericardial patch onto the posterior part of the prosthesis suture ring to prevent paravalvular leaks on a calcified annulus.

CorKnot: Automatic device for tightening and cutting suture knots, optimizing the security and speed of prosthesis fixation in cramped endoscopic environments.

Atrioventricular rupture: Major surgical complication related to the debridement of calcifications, characterized by a loss of continuity between the atrial and ventricular cavities.

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