Subannular Bentall in Pseudoaneurysm of Mitral-Aortic Intervalvular Fibrosa

A sixty-six-year-old man who had recently undergone aortic valve replacement presented to the emergency department after out-of-hospital cardiac arrest. Coronary angiography ruled out any significant coronary disease, and an echocardiogram showed a large aortic pseudoaneurysm of the mitral-aortic intervalvular fibrosa, so a subsequent CT scan was performed to confirm the finding.

A transesophageal echocardiogram evidenced a more than 47 mm cavity communicating with LVOT with a to-and-from cavity pulsatile flow, extending between posterior prosthetic aortic ring and the base of the anterior mitral valve leaflet. No paravalvular or intravalvular leak was detected.

The Surgery

A median redo sternotomy was performed using an oscillating saw. Cardiopulmonary bypass was instituted by means of aortic arch and bicaval cannulation, which is always important for a safe isolation of the aortic root in these kinds of re-interventions, and a left ventricular drain was inserted through the right superior pulmonary vein. Antegrade cold crystalloid cardioplegia was used to achieve cardioplegic arrest.

Next, the aorta was opened and the incision prolonged into the noncoronary sinus, as would be done in a commando procedure. In fact, the team came into the operating room with both options, leaving the choice between commando procedure or subannular composite root implantation to their interoperative findings.

The aortic prosthesis, a CE Perimount Magna 23, was removed and the aortic annulus debrided. The pseudoaneurysm entrance was then identified through the LVOT. The aortic root was then fully prepared with complete dissection down to the subannular area using electrocautery and scissors, and the coronary ostia were suspended.

Once a very low proximal suture line and healthy mitral valve tissues were identified, the team opted for a subannular Bentall procedure. In fact, it was decided not to reconstruct the annulus with a pericardial patch in order to avoid possible tension and retraction of the anterior mitral valve leaflet, thus causing severe mitral regurgitation, and to avoid graft dehiscence because of the friable anatomical structures involved. The abscess was therefore kept draining outside into the pericardial cavity.

Thanks to this kind of intervention, the patient could be treated without having to undergo a much more destructive and complex surgery such as the commando procedure.

Next, coronary buttons were reimplanted with a 6-0 polypropylene running suture after making holes in the conduit with a cautery. The conduit was then sutured to the distal aorta with a 4-0 polypropylene running suture. Intervention was then completed in the usual fashion.

The postoperative course was uneventful, and the patient was discharged after seven days. A postoperative echocardiogram showed good results with normal function of aortic prosthesis, a mild mitral regurgitation, and a complete exclusion of the pseudoaneurysm.

References

1. https://pubmed.ncbi.nlm.nih.gov/25468033/
2. https://pubmed.ncbi.nlm.nih.gov/23161575/

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