Left-sided 3D totally endoscopic mitral valve repair guided by left atrial appendage orientation in situs inversus totalis with mirror-image dextrocardia: a case report

Abstract

Background

Situs inversus totalis with mirror-image dextrocardia is a rare anatomical condition that creates specific challenges for minimally invasive mitral valve surgery. In totally endoscopic procedures, the reversed cardiac orientation may affect thoracic access, peripheral cannulation, left atrial exposure and accurate identification of mitral valve segments. We report a case of left-sided three-dimensional totally endoscopic mitral valve repair in this setting, with emphasis on operative planning and intraoperative segment orientation.

Case presentation

A 39-year-old woman presented with progressive exertional dyspnea and New York Heart Association class II to III symptoms. Echocardiography showed severe mitral regurgitation caused by posterior leaflet prolapse involving P2 and extending toward P3. Computed tomography angiography confirmed situs inversus totalis, mirror-image dextrocardia, a right-sided aortic arch, bilateral superior vena cavae and an uninterrupted inferior vena cava. A left-sided three-dimensional totally endoscopic approach was used with peripheral cardiopulmonary bypass through the left femoral vessels and supplemental left internal jugular venous drainage. Intraoperative segment orientation was deliberately re-established using the left atrial appendage as a fixed landmark to identify the A1/P1 side and distinguish it from A3/P3. Valve repair consisted of neochordal implantation to the prolapsing posterior leaflet and ring annuloplasty. Intraoperative transesophageal echocardiography, predischarge transthoracic echocardiography and 1-month follow-up transthoracic echocardiography showed no residual or recurrent mitral regurgitation, with preserved left ventricular systolic function at follow-up.

Conclusions

This case illustrates that valve-preserving, totally endoscopic mitral repair can be feasible in situs inversus totalis with mirror-image dextrocardia when imaging, cannulation, access and segment orientation are planned as a single operative strategy. The main educational message is that, in this case, the left atrial appendage served as a practical anatomical reference for maintaining segmental orientation during mitral repair in mirror-image anatomy.

Supplementary Information

The online version contains supplementary material available at https://doi.org/10.1186/s12872-026-06277-8.

Background

Situs inversus totalis (SIT) with mirror-image dextrocardia (MID) is uncommon and produces a complete right-left reversal of thoracoabdominal anatomy, a configuration that may become clinically important when cardiac surgery or invasive cardiovascular procedures are required [1, 2]. Although this anatomic arrangement may be well tolerated, it becomes highly relevant when cardiac surgery is required, because the operative field, port trajectory, great-vessel relationships and intracardiac orientation differ from those encountered in standard anatomy.

Minimally invasive mitral valve surgery has been reported to achieve acceptable early outcomes in selected patients, but its safety depends on careful patient selection, preoperative imaging, exposure planning and precise valve analysis [3–5]. In patients with SIT and MID, the surgeon must not simply transpose the usual operation to the opposite chest; rather, preoperative imaging must define the position of the left atrium, aortic arch, systemic venous return and peripheral cannulation route [1, 2, 6–9]. During repair, a further difficulty is accurate identification of mitral leaflet segments in a mirror-image field. Misidentifying the A1/P1 and A3/P3 sides may lead to an inappropriate repair strategy.

Published experience with mitral valve surgery in SIT and MID remains limited and consists mainly of isolated case reports or small case series describing sternotomy, transseptal exposure, minimally invasive access, valve replacement or combined valve procedures [1, 2, 6–12]. Although minimally invasive and totally endoscopic approaches have been reported, technical details on intraoperative spatial orientation, team communication and reproducible segmental referencing remain limited. This report describes a left-sided three-dimensional totally endoscopic mitral valve repair for severe degenerative mitral regurgitation in SIT with MID. The purpose is not to claim that preoperative CT planning or use of the left atrial appendage is novel or mandatory, but to highlight a practical orientation strategy that may help align valve analysis, repair planning and team communication in mirror-image anatomy.

Case presentation

A 39-year-old woman, 155 cm in height and 60 kg in weight, presented with progressive exertional dyspnea for more than 1 month and New York Heart Association class II to III symptoms. She had no known comorbidities, previous thoracic or cardiac surgery, or regular medication use. Transthoracic echocardiography performed at an outside hospital suggested severe mitral regurgitation (MR). After admission, transesophageal echocardiography (TEE), including three-dimensional imaging, was used for definitive anatomical assessment and operative planning, consistent with the role of echocardiography in defining mitral regurgitation mechanism and repair anatomy [5, 13].

TEE showed severe MR caused by predominant P2 prolapse extending toward P3, with chordal elongation and no chordal rupture. Left ventricular systolic function was preserved, with a left ventricular ejection fraction of 68%. Estimated pulmonary artery systolic pressure was 23 mmHg. Quantitative mitral assessment showed an intertrigonal distance of 28 mm, an annular anteroposterior diameter of 24 mm and a commissure-to-commissure diameter of 27 mm. The mitral-aortic angle was 109 degrees, suggesting a low risk of systolic anterior motion after repair.

Computed tomography angiography (CTA) confirmed SIT with MID and a right-sided aortic arch. CTA demonstrated a left-sided superior vena cava and a persistent right superior vena cava draining into the coronary sinus, with an uninterrupted inferior vena cava. The femoral vessels were suitable for peripheral cannulation, and the ascending aorta was free of calcification. Because the reversed cardiac orientation and anomalous systemic venous anatomy could affect cannulation and exposure, the operative plan was reviewed by a multidisciplinary team including cardiovascular surgeons, anesthesiologists, echocardiographers, operating-room staff and the cardiac intensive care unit team (Fig. 1A and B).

Fig. 1.

Multimodality imaging. (A) Computed tomography angiography showing situs inversus totalis with mirror-image dextrocardia, a right-sided aortic arch and bilateral superior vena cavae. (B) Transesophageal echocardiography showing severe mitral regurgitation. (C) Predischarge transthoracic echocardiography showing no residual mitral regurgitation

Surgical technique

A left-sided three-dimensional totally endoscopic approach was selected to align the operative trajectory with the mirror-image position of the left atrium and mitral valve. Ports were placed in the left third intercostal space for the auxiliary port, the left fourth intercostal space at the anterior axillary line for the main working port and the left fifth intercostal space at the midaxillary line for the camera port. A left atrial retractor was introduced through the right parasternal fourth intercostal space. This port was selected according to the shifted mediastinal orientation on preoperative CTA. After the interatrial groove was opened, the retractor blade was advanced under direct endoscopic vision into the left atrium. Because the heart and atrial septal plane were displaced toward the right hemithorax, traction from the right parasternal direction provided a favorable vector to elevate the atrial wall and open the mitral valve orifice toward the left-sided working ports. During exposure, the retractor was adjusted gradually rather than fixed at a single angle. The traction was directed mainly anteriorly and slightly rightward to avoid excessive compression of the mediastinal structures and to maintain a coaxial view of the mitral valve. No additional dedicated counter-traction device was required. Minor counter-traction and exposure adjustment were achieved through the auxiliary port when needed, while the retractor maintained stable en face visualization of the mitral valve for leaflet analysis, neochordal implantation and annuloplasty. The primary surgeon stood on the left side of the operating table, and the first assistant stood on the right side of the table. The second assistant, who controlled the three-dimensional endoscope, stood on the same side as the primary surgeon and was positioned to the surgeon’s left. Standard right-handed long-shafted endoscopic instruments were used. The mirror-image anatomy did not require dedicated left-handed instruments or a persistent cross-handed operating posture. During the procedure, the right hand of the primary surgeon was used as the dominant working hand through the main working port. Sutures, needles and other materials were introduced through the auxiliary port by the surgeon’s left hand and then transferred to the right hand at the main working port when precise manipulation was required. This hand-to-hand transfer through the left-sided port system helped maintain familiar right-handed instrument handling while adapting to the reversed thoracic orientation (Fig. 2A and B; Video.1).

Fig. 2.

Surgical setup and repair technique. (A) Port placement for the left-sided three-dimensional totally endoscopic approach. (B) Operative view showing instrument orientation through the working ports. (C) Endoscopic view of posterior leaflet prolapse. (D) Competent mitral valve after neochordal implantation and annuloplasty

Cardiopulmonary bypass was established through the left femoral artery and vein, with supplemental venous drainage through the left internal jugular vein because of the bilateral superior vena cava anatomy. After cooling to mild hypothermia, the ascending aorta was crossclamped and antegrade cold high-potassium blood cardioplegia was delivered through an aortic root cannula. The left atrium was opened through the interatrial groove.

The principal technical issue was segmental orientation of the mitral valve in the reversed intracardiac anatomy. Before valve analysis, the left atrial appendage (LAA) was used as a fixed anatomical landmark to identify the A1/P1 side and distinguish it from A3/P3. This approach is anatomically plausible because the A1/P1 segments are located toward the anterolateral commissural side, close to the LAA in standard mitral valve orientation [14, 15]. Because the appendage remains adjacent to this commissural side despite mirror-image orientation, it provided a reproducible reference point for segmental analysis.

Valve inspection showed myxomatous thickening and prolapse of the P2 segment, extending toward P3, with chordal elongation and no chordal rupture. There was no relevant annular calcification, annular disjunction or Barlow-type change (Fig. 2C). A nonresectional repair was performed to preserve leaflet tissue and restore coaptation. Two pairs of neochordae were implanted to the prolapsing posterior leaflet, followed by annuloplasty with a 26-mm Medtronic ring. The saline test showed a broad coaptation surface without residual regurgitation. Carbon dioxide insufflation was used for de-airing before closure of the left atriotomy (Fig. 2D).

Outcome and follow-up

Total operative time was 230 min, cardiopulmonary bypass time was 196 min and aortic crossclamp time was 129 min. The 67-minute interval between the cardiopulmonary bypass and aortic crossclamp times mainly reflected planned peripheral bypass management in mirror-image anatomy, including confirmation and optimization of femoral and left internal jugular venous drainage for bilateral superior vena cava anatomy, controlled rewarming, systematic de-airing and intraoperative transesophageal echocardiographic assessment before weaning from bypass. It was not related to conversion, major bleeding or intraoperative complications. Estimated blood loss was 300 mL, and no transfusion was required. The operation was completed without conversion to sternotomy or valve replacement. No intraoperative complication occurred.

Intraoperative TEE showed no systolic anterior motion and no residual MR. The mean transmitral gradient was 2 mmHg, the peak transmitral velocity was 1.07 m/s and the left ventricular outflow tract peak velocity was 1.10 m/s. The patient was extubated 6 h postoperatively and transferred out of the intensive care unit on postoperative day 2 without complications. Predischarge transthoracic echocardiography showed no residual MR, a mean transmitral gradient of 1.44 mmHg, a peak transmitral velocity of 1.56 m/s, a coaptation height of 9.6 mm and a left ventricular ejection fraction of 56% (Fig. 1C). At the 1-month outpatient follow-up, the patient was alive, reported no specific discomfort and had New York Heart Association class II functional status. Follow-up transthoracic echocardiography showed no recurrent MR, a mean transmitral gradient of 4 mmHg, a peak transmitral velocity of 1.48 m/s and a left ventricular ejection fraction of 62%.

Discussion and conclusions

This case is educational because the rare anatomical condition changed the operative problem from a routine degenerative posterior leaflet repair into a procedure requiring deliberate reorientation [1, 2, 6–12]. In standard anatomy, port placement, atrial exposure and leaflet segment identification are supported by familiar spatial relationships. In SIT with MID, those relationships are reversed. A successful endoscopic repair therefore requires preoperative imaging that answers practical operative questions, including which hemithorax provides the most direct route to the left atrium, whether peripheral cannulation is safe and whether systemic venous anomalies require additional drainage.

The first technical principle is that CTA should be used not only to confirm SIT and MID, but also to define the aortic arch configuration, superior and inferior caval anatomy, femoral vessel suitability and ascending aortic safety [2, 6, 8, 9]. In this patient, left-sided thoracic access matched the mirror-image position of the mitral valve, while the presence of bilateral superior vena cavae supported supplemental jugular venous drainage to maintain adequate venous return during cardiopulmonary bypass.

The second principle is that three-dimensional visualization may be particularly useful in mirror-image anatomy. Three-dimensional echocardiography has been shown to improve assessment of mitral valve prolapse and segmental anatomy, and totally three-dimensional endoscopic mitral surgery has recently been reported in SIT [5, 8, 16]. Depth perception can facilitate leaflet analysis, neochordal placement and annuloplasty when the surgeon is operating in a reversed field. In this setting, the three-dimensional platform should be presented not merely as a minimally invasive tool, but as an aid to accurate valve-preserving reconstruction.

Another practical principle is reliable mitral segment orientation. In MID, visual intuition based on standard anatomy may be misleading. We deliberately used the LAA as a fixed landmark to identify the A1/P1 side and separate it from A3/P3 before deciding the repair strategy [14, 15]. This step helped maintain segmental orientation and supported accurate neochordal implantation to the prolapsing posterior leaflet. We acknowledge that neither preoperative CT-based planning nor the use of anatomical landmarks during mitral valve repair is, by itself, novel. We also do not suggest that the LAA landmark is mandatory for all repairs in SIT with MID, because the prolapsing leaflet segment can often be identified by direct endoscopic inspection. However, in a totally endoscopic mirror-image field, segmental orientation is not only a matter of visual recognition by the primary surgeon, but also a matter of shared spatial language among the surgeon, assistant, echocardiographer and operating-room team. In this context, the LAA provided a simple and stable reference point for aligning preoperative TEE findings, intraoperative valve inspection and repair planning. Although precise segmental naming may not change every repair maneuver in a straightforward posterior leaflet prolapse, it can improve consistency in describing the lesion, selecting the neochordal target and communicating the repair strategy in an anatomically reversed field.

The operative and perfusion times should be interpreted cautiously in relation to the limited published experience. Prior reports of mitral valve surgery in situs inversus totalis with mirror-image dextrocardia are heterogeneous with respect to surgical access, exposure route and operative objective, ranging from median sternotomy or transseptal exposure to minimally invasive thoracotomy and totally endoscopic approaches, and from valve replacement to valve repair or combined valve procedures [1, 2, 6–12]. These differences make raw comparisons of total operative time, cardiopulmonary bypass time and aortic crossclamp time difficult. In the present case, the total operative time, cardiopulmonary bypass time and aortic crossclamp time were 230, 196 and 129 min, respectively. These times should be viewed as a composite reflection of several technical demands rather than as isolated performance metrics: pre-bypass confirmation of peripheral cannulation strategy, optimization of femoral and left internal jugular venous drainage in the setting of bilateral superior vena cavae, left-sided endoscopic exposure, re-establishment of mitral segment orientation in mirror-image anatomy, valve-preserving repair with neochordal implantation and annuloplasty, systematic de-airing and intraoperative transesophageal echocardiographic confirmation before weaning from bypass. Thus, although the perfusion time was not short, it was consistent with the deliberate safety checks required for a totally endoscopic repair in this unusual anatomy.

This case adds to the limited literature on mitral valve surgery in SIT with MID by emphasizing a reproducible orientation strategy for valve-preserving totally endoscopic repair. It should not be interpreted as evidence that this approach is superior to other surgical approaches. Rather, it demonstrates that complex mirror-image anatomy does not necessarily preclude repair when imaging, access, cannulation and valve orientation are integrated into a single operative plan.

In conclusion, left-sided three-dimensional totally endoscopic mitral valve repair can be feasible in selected patients with SIT and MID. The educational value of this case lies in integrating detailed preoperative imaging, left-sided endoscopic access, peripheral cannulation planning and LAA-guided segment orientation into a coherent operative strategy for mitral valve repair in mirror-image cardiac anatomy.

Abbreviations

CPB

Cardiopulmonary bypass

CTA

Computed tomography angiography

LAA

Left atrial appendage

MID

Mirror-image dextrocardia

MR

Mitral regurgitation

SIT

Situs inversus totalis

TEE

Transesophageal echocardiography

Authors’ contributions

QW, DL and GQ collected clinical data and drafted the manuscript. YL, PZ, XC, RQ, BZ, YC and GD contributed to perioperative management and data interpretation. XL and BS contributed echocardiographic assessment. HL and DH contributed anesthetic management. ZG and MX contributed operating-room coordination and technical support. QZ and CM performed the operation, supervised the report and critically revised the manuscript for important intellectual content. All authors read and approved the final manuscript.

Funding

This study received no specific funding.

Data availability

No datasets were generated or analysed during the current study.

Declarations

Ethics approval and consent to participate

Institutional Review Board approval was not required for this single de-identified case report according to institutional policy. Written informed consent was obtained from the patient.

Consent for publication

Written informed consent for publication of the patient’s clinical details and accompanying images and videos was obtained from the patient.

Competing interests

The authors declare no competing interests.