Aortic and Mitral Valve Replacement With Reconstruction of the Intervalvular Fibrous Body: How to Do the Commando Procedure

Background

The intervalvular fibrous body (IFB) is a structure between medial and lateral trigone that connects the aortic and mitral valves. From the atrial side, the dome of the left atrium is also an important part because it separates the anterior mitral valve from the aortic root. The fibrous body is mainly involved due to abscess formation by the infective endocarditis (1). The radical debridement of all involved tissue with reconstruction of the IFB and aortic and mitral valves replacement may be the only option available to treat these patients and prevent persistent infective endocarditis. In 1997, David and colleagues described a technique using a patch of bovine pericardium followed by aortic and mitral valve replacement (2). The reported operative mortality ranges between 10-30% and there is a high incidence of recurrent infection (2–4). Fortunately, the involvement of the IFB is rare, even in very high-volume centers, but when it is necessary, its restoration represents a surgical challenge (5).

Technique

Exposition of Aortic Valve, Mitral Valve, and Intervalvular Fibrous Body

A conventional median sternotomy was performed. The patient was connected to cardiopulmonary bypass. The temperature was lowered to 32ºC and antegrade plus retrograde Del Nido blood cardioplegia was infused. According to the technique described by David and colleagues, an oblique aortotomy was performed and the aortic valve was excised. The aortotomy was enlarged through the noncoronary aortic sinus and aortic annulus until reaching the intervalvular fibrous body. The dome of the left atrium was opened generously towards the right pulmonary artery.

The mitral valve and the diseased intervalvular fibrous body were radically excised. The extensiveness of the resection and reconstruction in cases of endocarditis depends on what degree the neighboring tissues are involved by the infectious process.

In patients who underwent elective aortic and mitral valve replacement to treat patient-prosthesis mismatch, the intervalvular fibrous body was simply divided.

Mitral Valve Replacement

Ventricular pledgeted mattress sutures of Ti-Cron (Covidien-Medtronic Minneapolis, MN, USA) 2-0 were passed through the posterior mitral annulus from the lateral to the medial fibrous trigone. All the stitches were passed through the sewing ring of the mitral prosthesis that was lowered into position and tied. The authors only cut the extremes of the remaining sutures to use them as a reference.

Reconstruction of the Intervalvular Fibrous Body

As the authors have previously described (6), a triangular single-folded glutaraldehyde fixed bovine pericardium patch was used to reconstruct the intertrigonal mitral aortic junction. The patch was secured laterally to the lateral and medial fibrous trigones with a continuous 3-0 polypropylene suture. The authors fixed the patch as close as possible to the last mitral sutures to avoid a paravalvular leak. The central part was secured to the mitral prosthesis with pledgeted stitches.

The left atriotomy was closed with the outer half of the patch using one of the 3-0 polypropylene sutures of every trigone. After the authors closed the dome of the left atrium, they proceeded to suture the inner patch to the margins of the aortic wall, thus forming the new subaortic curtain and the posterior segment of the left ventricular outflow tract.

Aortic Valve Replacement

The authors sized the aortic prosthesis taking the reference of the location of the trigones. A prosthetic aortic valve was secured to the aortic annulus and to the pericardial patch. During the aortic valve replacement, the stitches in the pericardial patch can be passed from the aortic sewing ring to the outer side of the pericardial patch. The remaining inner half patch was used to close the right side of the aortotomy.

Comment

The main indications of this technique include active infective endocarditis with abscess, extensive calcification, lack of fibrous tissue because of multiple previous operations, or prevention of the patient-prosthesis mismatch (2,3). The reconstruction of the intervalvular fibrous body is very unusual and in cases of extensive destruction of intervalvular fibrous body due to endocarditis, it is a major surgical challenge, even in high-volume centers. It is important to understand and know this technique because conventional surgery does not normally solve this problem. In order to perform this reconstruction, it is necessary to have a good knowledge of the anatomic relationships of the various components along the left atrioventricular groove and the left ventricular outflow tract. The approach and technique described by David et al (2) allows for the optimal exposure of most intracardiac structures, including the posterior mitral annulus (even in cases of reoperation) and the radical debridement of the involved tissues.

It is important to avoid the use of excessive large prosthetic mitral valves because they fill the left ventricle and do not leave space for the prosthetic aortic valve. The aortic valve should be implanted approximately 1 centimeter above the mitral valve to avoid a large patch between the prosthesis. The authors recommend closing the left atrium roof before the implant of the prosthetic aortic valve, because later it is more difficult to reach and close properly.

This technique is a complex procedure with a high operative morbidity and mortality, but one must not forget that in some cases, it is the only option available to treat these patients (2,4,7). Thus, a framework of technical considerations can help surgical teams achieve reproducible success with this technique, decreasing the technical failures (3). The authors believe that the multimedia resource allows other colleagues to familiarize themselves with this technique and can improve the results of these cases and the prognosis of patients when facing reconstruction of the intervalvular fibrous body.

References

1. Davierwala PM, Binner C, Subramanian S, Luehr M, Pfannmueller B, Etz C, et al. Double valve replacement and reconstruction of the intervalvular fibrous body in patients with active infective endocarditis. Eur J Cardiothorac Surg. 2014;45(1):146-152.
2. David TE, Kuo J, Armstrong S. Aortic and mitral valve replacement with reconstruction of the intervalvular fibrous body. J Thorac Cardiovasc Surg. 1997;114(5):766-772.
3. De Oliveira NC, David TE, Armstrong S, Ivanov J. Aortic and mitral valve replacement with reconstruction of the intervalvular fibrous body: an analysis of clinical outcomes. J Thorac Cardiovasc Surg. 2005;129(2):286-290.
4. Forteza A, Centeno J, Ospina V, Lunar IG, Sánchez V, Pérez E, et al. Outcomes in aortic and mitral valve replacement with intervalvular fibrous body reconstruction. Ann Thorac Surg. 2015;99(3):838-845.