Aortopulmonary window closure and mitral valve repair in a 7-month-old infant

Aortopulmonary window and functional mitral regurgitation: a surgical challenge in infants

The aortopulmonary window (APW) is a rare cardiovascular malformation, representing only 0.1 to 0.2% of congenital heart diseases. Characterized by an abnormal communication between the ascending aorta and the pulmonary trunk, it can, when large, induce a massive left-to-right shunt and early systemic pulmonary hypertension. This case report documents the management of a 7-month-old infant presenting with a 12 mm APW complicated by severe functional mitral regurgitation (MR) (grade 3/4), resulting from annular dilation due to volume overload.

The objective of this presentation is to detail a combined surgical strategy: defect closure using a biological patch via a transaortic approach, associated with concomitant mitral repair. Clinicians tested the hypothesis that early intervention using deep hypothermic circulatory arrest would allow for optimal exposure of the defect, while correcting functional MI through a conservative commissural suture technique, thus avoiding the use of prosthetic material in a very young patient. The major challenge lay in the use of multimodal imaging (echocardiography and CT scan) to secure the anatomical relationships with the coronary arteries prior to the operative procedure.

Methodology and Management Protocol

This clinical case report has been documented in accordance with the SCARE 2025 recommendations. It describes the management of a single patient, a 7-month-old male infant, presenting with a type I aortopulmonary window (APW) associated with severe functional mitral regurgitation.

The diagnostic and therapeutic protocol was structured as follows:

• Initial evaluation: Transthoracic echocardiography (TTE) having identified a 12 mm communication with exclusive left-to-right shunt, suspected systemic pulmonary hypertension and grade 3/4 mitral regurgitation due to annular dilatation.
• Additional imaging: Multidetector Computed Tomography (CT) to specify the location of the defect and ensure the safety distance from the coronary arteries. Cardiac catheterization was not performed.
• Surgical procedure: Performed via median sternotomy under deep hypothermic circulatory arrest to ensure bloodless transaortic exposure.
• Repair techniques:
  • PDA closure using a biological patch via a longitudinal aortotomy.
  • Concomitant mitral repair using a single commissural/coaptation suture, without prosthetic material (native valve preservation).
• Postoperative follow-up: Clinical and echocardiographic analysis during hospitalization (extubation at D2, discharge at D7) and during follow-up at 1 month to evaluate the absence of residual shunt and the reduction of mitral regurgitation.

The total duration of the procedure was 90 minutes.

Clinical results and operative data

Preoperative evaluation by transthoracic echocardiography and CT angiography allowed for the quantification of the hemodynamic impact of the malformation. Initial cardiac biometric data revealed significant dilation of the left cavities.

The surgical procedure, lasting a total of 90 minutes, consisted of the closure of the PAF using a biological patch via a longitudinal aortotomy under deep hypothermic circulatory arrest. Simultaneously, a conservative mitral valve repair was performed using a single commissural/coaptation suture point, without the implantation of prosthetic material.

The immediate postoperative outcomes and the qualitative observations reported are as follows:

• Respiratory support: Weaning from mechanical ventilation and successful extubation on postoperative day 2 in the intensive care unit.
• Postoperative echocardiography: Confirmation of a satisfactory repair without residual shunt. Pulmonary arterial pressure was noted as reduced compared to preoperative systemic levels.
• Valvular function: Mitral regurgitation has been reduced to a stage qualified as mild.
• Clinical outcome: Absence of neurological deficit or postoperative seizures. The patient was discharged home on D7.

Clinical analysis and surgical strategy

The results of this management demonstrate that early intervention effectively corrects the hemodynamic consequences of a large APF. The surgical approach via longitudinal aortotomy under deep hypothermic circulatory arrest allowed for optimal exposure of the defect. The use of a transaortic biological patch proved effective in eliminating the left-to-right shunt, leading to an immediate postoperative reduction in pulmonary arterial pressure.

The uniqueness of this case lies in the concomitant treatment of functional mitral regurgitation. Rather than relying solely on reverse remodeling post-shunt closure, the surgeon performed a mitral valve repair using a single commissural suture. This valve-preserving technique, without the use of prosthetic material, reduced the MR to a mild grade, confirming the relevance of direct intervention on the dilated annulus in cases of massive regurgitation.

Multimodal imaging played a decisive role. While transthoracic echocardiography established the diagnosis, multislice computed tomography (MSCT) was crucial for mapping the distance between the defect and the coronary arteries, thereby securing the surgical procedure. Although early success is documented by rapid extubation and discharge at D7, the study remains limited by its unique nature (case report) and the lack of follow-up on the long-term evolution of the mitral repair in a growing patient.

Summary of results

The surgical closure of this 12 mm ASD using a biological patch, performed under deep hypothermic circulatory arrest, was associated with a mitral valve repair using a coaptation stitch. Early postoperative results confirm the absence of residual shunt, a reduction in pulmonary arterial pressures, and a regression of mitral regurgitation to grade 1/4 (mild).

In concrete terms, for the practitioner:

• Contribution of multimodal imaging: Preoperative CT angiography is crucial for precisely locating the defect in relation to the coronary ostia, making it possible to secure the surgical procedure without systematically resorting to invasive catheterization.
• Management of mitral insufficiency (MI): Severe functional MI in infants can be effectively treated during the same session using a simple commissural suture/coaptation technique, thus avoiding the use of prosthetic material.
• Early intervention: Faced with a massive left-to-right shunt and systemic-level pulmonary hypertension, surgery must be performed promptly to prevent irreversible pulmonary vascular damage.

Technical lexicon

Aortopulmonary window (APW): Abnormal communication between the ascending aorta and the pulmonary trunk, despite the presence of two distinct semilunar valves.

DHCA (Deep Hypothermic Circulatory Arrest): Deep hypothermic circulatory arrest technique allowing the interruption of blood flow to facilitate complex surgery on large vessels.

MSCT (Multislice Computed Tomography): Multislice scanner used to obtain precise anatomical mapping of vascular communications and the origin of the coronary arteries.

Functional mitral regurgitation: Mitral valve regurgitation caused not by an intrinsic lesion of the leaflets, but by a dilation of the mitral annulus secondary to volume overload.

Commissural coaptation point: Simplified valvular suture technique aimed at bringing the mitral valve leaflets together to restore competence without the implantation of prosthetic material.

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