Left Atrial Appendage Clipping: 100% technical success via minithoracotomy

Clinical context and challenges of LAA exclusion

Left atrial appendage (LAA) exclusion carries a Class I recommendation to reduce the risk of cardioembolic stroke in patients with atrial fibrillation (AF). While minimally invasive mitral valve surgery via right minithoracotomy has become established to reduce sternal morbidity, accessing the LAA within this restricted operative field remains complex. Historical suturing techniques are considered unreliable, with incomplete closure rates reaching 36 to 60%, paradoxically creating a low-flow thrombogenic nidus.

Study objectives and hypotheses

This monocentric study presents the largest series reported to date (n=40) concerning an innovative LAA exclusion technique using an epicardial clip (AtriClip Pro) deployed via the transverse sinus. The objective was to evaluate the technical feasibility and safety of this approach during minimally invasive mitral surgery conducted between June 2023 and May 2026. The authors test the hypothesis that suture guidance via the transverse sinus allows for precise and stable positioning of the device at the LAA ostium, ensuring complete exclusion without requiring additional thoracic access, while maintaining the benefits of minimally invasive surgery.

Methodology: minimally invasive exclusion protocol

This single-center retrospective cohort study involved 40 consecutive patients with atrial fibrillation (AF) who underwent mitral surgery via right minithoracotomy between June 2023 and May 2026. The primary objective was to evaluate the feasibility of left atrial appendage (LAA) exclusion via the transverse sinus.

• Accès et CEC : L'intervention a été réalisée par une minithoracotomie latérale droite au niveau du 4ème ou 5ème espace intercostal. La circulation extracorporelle (CEC) a été établie par une cannulation fémorale percutanée guidée par échographie.
• Clipping procedure: Once the intracardiac procedure was completed and under aortic clamping, the left atrial appendage was identified via the transverse sinus. A 4-0 polypropylene suture was passed around the apex of the appendage to guide and position the AtriClip Pro device (35 mm, 40 mm, or 45 mm models) at the base of the ostium.
• Success criteria: Procedure success was systematically confirmed by intraoperative transesophageal echocardiography (TEE) after aortic clamp removal. Technical success was defined by complete occlusion of the ostium with no residual flow detectable by color Doppler.
• Statistical analysis: Data were processed descriptively, with continuous variables reported as mean ± standard deviation (SD) or median depending on the distribution, and categorical variables expressed as absolute values and percentages.

Technical efficiency and deployment success

The study reports a 100% technical success rate (n=40) for the deployment of the AtriClip Pro via right minithoracotomy. Complete closure of the left atrial appendage (LAA), defined by the absence of residual flow on color Doppler and a residual stump of less than 1 cm, was systematically confirmed by intraoperative transesophageal echocardiography (TEE) after the release of the aortic cross-clamp.

The choice of device size was dictated by pre-deployment TEE measurements:

• 35 mm clip: 90% of patients (n=36)
• 40 mm Clip: 8% of patients (n=3)
• 45 mm Clip: 2% of patients (n=1)

Operative data and concomitant procedures

Mitral valve surgery consisted mainly of repair (90%, n=36), compared to 10% replacements (n=4). Concomitant cryoablation for atrial fibrillation (AF) was performed in 31 patients (78%).

Safety and clinical outcomes

The recorded in-hospital mortality rate is 0%. Immediate postoperative complications include:

• Re-intervention: One patient (3%) required a re-thoracotomy for bleeding.
• Neurological events: One case of postoperative stroke has been reported.
• Hemodynamic support: Two patients required ECMO assistance.

Regarding the heart rate at hospital discharge, 18 patients (45%) were in sinus rhythm. In the subgroup that underwent concomitant cryoablation (n=31), this rate rose to 52% (n=16).

Note: In accordance with the descriptive design of this retrospective series, no formal inferential statistical analysis (p-values) was performed by the authors.

Discussion: Reliable exclusion in a reduced field

The results of this study, involving the largest series reported to date (n=40), demonstrate that left atrial appendage (LAA) exclusion using an epicardial clip is not only feasible but highly reliable during mitral surgery via right minithoracotomy. With a 100% deployment success rate and zero in-hospital mortality, this technical approach dispels doubts regarding the feasibility of a procedure perceived as complex within a restricted operative field.

The major contribution lies in the use of the transverse sinus to guide the clip via a 4-0 polypropylene suture. This technical tip allows for precise positioning at the ostium without direct manual manipulation, thus overcoming the lack of visibility inherent to the minimally invasive approach. Unlike conventional suture techniques, for which the cited literature highlights inconsistency (36 to 60% failure rate), the use of the AtriClip Pro here guarantees complete occlusion confirmed by intraoperative transesophageal echocardiography (TEE), eliminating the risk of a pro-thrombotic residual pouch.

The weak point, however, lies in the retrospective and monocentric nature of the study, with a sample size that remains modest (40 patients). While safety is confirmed, long-term follow-up will be necessary to validate the effective reduction of strokes, especially since only 45% of patients were in sinus rhythm at discharge. Nevertheless, the absence of major complications specifically related to the clip and the lack of need for additional incisions make this technique a potential standard for concomitant cardioembolic prevention.

Summary of results

This series of 40 patients demonstrates the clinical efficacy of the epicardial clip via the transverse sinus: 100% deployment success and 0% hospital mortality. Despite postoperative morbidity including one stroke (3%) and two cases requiring ECMO, 52% of patients who underwent concomitant cryoablation were discharged from the hospital in sinus rhythm.

In concrete terms, for the practitioner:

• Leverage the transverse sinus: The use of a 4-0 guide suture via this route allows for precise positioning of the clip at the ostium, overcoming the narrowness of the surgical field in right minithoracotomy without requiring an additional incision.
• Validated by TEE: Systematic confirmation by intraoperative transesophageal echocardiography is imperative to ensure the total absence of residual flow and an atrial stump of less than 1 cm.
• Standardise the "One-Stop": This technique secures the global management of AF patients by simultaneously treating valvular pathology, arrhythmia, and thromboembolic risk during a single minimally invasive procedure.

Technical lexicon of the study

AtriClip Pro: Second-generation epicardial exclusion device, composed of a self-closing nitinol structure covered with a polyester mesh. It integrates a suture guide channel allowing precise positioning at the base of the left atrial appendage (LAA).

Transverse sinus: Pericardial anatomical space used as a passage for the guide suture. In this technique, it allows the tip of the auricle to be grasped and the clip to be brought towards the ostium under direct vision.

Right minithoracotomy: Minimally invasive surgical approach performed through the 4th or 5th intercostal space. It replaces sternotomy for access to the mitral valve and allows, via this series, the concomitant exclusion of the left atrial appendage.

Residual stump: Persistent portion of the left auricle after incomplete exclusion. The study highlights that conventional suturing techniques show high rates of stumps, creating a low-flow zone conducive to thrombus formation.

Left atrial cryoablation: Concomitant procedure using a cryoprobe to treat atrial fibrillation (AF). In this series, it was performed in 78% of patients to restore sinus rhythm.

Transoesophageal echocardiography (TOE): Systematic intraoperative imaging used to confirm complete occlusion of the atrial appendage ostium and the absence of residual flow after clip deployment and aortic declamping.

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