Situs inversus: the challenge of totally endoscopic 3D mitral valve repair

The challenge of Situs Inversus Totalis in endoscopic surgery

Situs Inversus Totalis (SIT) with mirror-image dextrocardia (MID) imposes major anatomical constraints for minimally invasive mitral valve surgery. Beyond the reversed thoracic access, the difficulty lies in peripheral cannulation, left atrial exposure, and precise identification of mitral segments in a reversed spatial geometry. This case report describes the management of a 39-year-old patient presenting with progressive exertional dyspnea (NYHA class II to III), related to severe mitral regurgitation due to posterior leaflet prolapse involving segments P2 and P3.

Objectives and segmental identification strategy

The objective of this procedure is to demonstrate the feasibility of a reconstructive mitral valve repair using a fully 3D endoscopic approach via a specific left-sided access. The surgical strategy incorporates left femoral cannulation and additional internal jugular drainage to address the patient's vascular specificities, notably a bilateral superior vena cava. The central technical challenge relies on securing spatial orientation: the authors propose the systematic use of the left auricle as a fixed anatomical landmark. This landmark allows for the reliable identification of the A1/P1 side and its distinction from the A3/P3 complex, thus ensuring the precision of neochordae implantation and annuloplasty despite the mirror anatomy.

Methodology and operative approach

This clinical case report details the management of a 39-year-old female patient presenting with severe mitral regurgitation (NYHA class II-III) related to a posterior leaflet prolapse (P2 and P3 segments), in a context of situs inversus totalis with mirror-image dextrocardia.

The surgical protocol was specifically adapted to this inverted anatomy via a left three-dimensional (3D) endoscopic approach, including the following steps:

• Preoperative imaging: A CT angiography was used to confirm the situs inversus, the right-sided aortic arch, bilateral superior venae cavae, and the integrity of the inferior vena cava.
• Access and cannulation: Establishment of peripheral extracorporeal circulation via the left femoral vessels, combined with additional left internal jugular venous drainage.
• Segmental orientation: Deliberate use of the left atrial appendage as a fixed anatomical landmark to identify the A1/P1 side and distinguish it from the A3/P3 side.
• Repair procedure: Neochord implantation on the posterior leaflet and ring annuloplasty.

L'évaluation des résultats a été effectuée par échocardiographie transœsophagienne peropératoire, puis par échocardiographie transthoracique avant la sortie hospitalière pour mesurer le gradient transmitral et l'éventuelle régurgitation résiduelle.

Intervention results and clinical observations

The case concerns a 39-year-old female patient presenting with progressive exertional dyspnea (NYHA stage II-III). Initial echocardiography revealed severe mitral regurgitation (MR) due to posterior leaflet prolapse (P2 extending towards P3). Computed tomography angiography confirmed a complex anatomical configuration, detailed in the table below:

L'approche chirurgicale a consisté en une technique totalement endoscopique 3D par le côté gauche. La circulation extracorporelle (CEC) a été établie via les vaisseaux fémoraux gauches, complétée par un drainage veineux jugulaire interne gauche.

Intraoperative observation required a deliberate reorientation of the valve segments. The left atrial appendage (LAA) was used as a fixed anatomical landmark to identify with certainty the A1/P1 side and distinguish it from the A3/P3 side. The repair included:

• L'implantation de néocordages sur le feuillet postérieur prolabé (P2/P3).
• An annuloplasty with ring.

Les résultats post-opératoires immédiats et à court terme sont les suivants :

• Intraoperative transoesophageal echocardiography (TOE): Absence of residual mitral regurgitation.
• Transthoracic echocardiography (TTE) before discharge: Absence of residual MR and maintenance of low transmitral gradients.

Clinical analysis and challenges of the mirror approach

This case report demonstrates that 3D totally endoscopic mitral valve surgery (TEMVR) is technically feasible in patients presenting with situs inversus totalis (SIT) with mirror-image dextrocardia. The success of the procedure in this 39-year-old patient relied on a complete reversal of the standard operative strategy. The use of a left thoracic approach and left femoral cannulation (supplemented by left internal jugular) allowed for compensation of the reversed anatomy and the presence of a right-sided aortic arch. Clinically, the favorable outcome (absence of residual leak and low gradients) validates the transposition of repair techniques, such as neocord implantation and annuloplasty, to this rare anatomical configuration.

Reliability of landmarks and limits

The main challenge identified is not only access, but intra-atrial segmental orientation. In this mirrored anatomy, the risk of confusion between segments A1/P1 and A3/P3 is real. The authors emphasize that using the left auricle as a fixed landmark was decisive for identifying the anterior commissure with certainty and precisely treating the P2-P3 prolapse. Although this single case study does not allow for the generalization of statistical protocols, it highlights an intrinsic limitation: the need for exhaustive preoperative imaging (CT angiography) to identify associated variants, such as the bilateral superior vena cavae encountered here, which determine the success of peripheral perfusion.

Implications for surgical practice

This observation confirms that the anatomical complexity of the SIT-MID is not a contraindication to endoscopy, provided that imaging, cannulation, and exposure are integrated into a unified strategy. Unlike conventional approaches, the surgeon must consciously reset their mental framework for spatial orientation.

Summary of results

This procedure in a 39-year-old patient demonstrates the feasibility of a fully endoscopic 3D mitral repair in a case of situs inversus totalis. The procedure, combining neocords and annuloplasty via a left-sided approach, resulted in a complete correction of the mitral regurgitation (P2-P3 prolapse) with low residual gradients at discharge.

In practical terms, for the practitioner:

• Reverse the surgical approach: Adapt the thoracic access and peripheral cannulation (left femoral and jugular vessels) to strictly respect the inverted symmetry imposed by dextrocardia.
• Secure segmental orientation: Systematically use the left atrial appendage as a fixed anatomical landmark to identify the A1/P1 side with certainty, thus avoiding any spatial confusion during mirror valve repair.
• Map the vascular network: Perform an exhaustive preoperative CT angiography to identify associated variants, such as a persistent left superior vena cava or a right-sided aortic arch, in order to secure the extracorporeal circulation planning.

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