The Hemi-Commando Arrives: A New Technique for Double-Valve Endocarditis

Severe infective endocarditis (IE) and its treatment can devastate the tissues around the heart. The surgical repair and replacement of IE-affected tissues around the aortic and mitral valves — especially the intervalvular fibrous body (IFB) in cases of prosthetic valve endocarditis — is a great challenge. Some surgeons call it a “commando operation.”

But a new technique developed at Cleveland Clinic is coming to the relief of the commando operation. Instead of replacing both infected valves, the technique replaces the aortic valve and repairs the mitral valve using tissue with a transplanted segment of donor heart aorta and mitral valve.

The procedure, formally known as the incorporated aortomitral homograft, was developed by Cleveland Clinic cardiothoracic surgeon Jose Navia, MD, who calls it a “hemi-commando.” It addresses the need to repair or reconstruct the IFB in the treatment of bivalvular IE.

Fixing the heart’s fibrous structure

The IFB is an essential piece of structural tissue between the aortic and mitral valves that’s often damaged in bivalvular IE. In a normal commando operation, the IFB is reconstructed using autologous or bovine pericardial tissue.

“Most of these operations are reoperations,” says Dr. Navia. “Very often they are in patients with prosthetic aortic valve endocarditis where the infection aggressively extends and destroys not just the aortic annulus, but also the IFB and the anterior leaflet of the mitral valve.”

Transplanting the homograft as a unit

To illustrate the hemi-commando’s applicability, Dr. Navia describes the case of a 64-year-old woman with a mechanical aortic valve who presented with fever, shortness of breath and congestive heart failure and was found to be blood culture-positive for Escherichia coli. Echocardiography suggested the presence of dense bacterial colonies and vegetation around the aortic prosthesis, IFB and mitral valve, with abscesses around the aortic root. Moderate mitral valve regurgitation was detected.

These findings were borne out in the operating room, where the prosthetic valve was removed and involvement of the aortic root, IFB and mitral valve was noted.

It is usual in cases of bivalvular IE for only the anterior leaflet of the mitral valve to be infected. That’s because the anterior leaflet is most likely to receive the extension of the infection through jets, sometimes eccentric, from the aortic valve, which is most often the initial site of infection.

In this case, Dr. Navia used a homograft including the aortomitral membrane, the ascending aorta, the dome of the left atrium, and part of the mitral valve annulus. The homograft was transplanted intact, as a unit (Figure 1). An annuloplasty ring was placed around the mitral valve.

Figure 1. Illustrations of three stages of the hemi-commando procedure. Top: Surgeon’s view of the heart after complete removal of infected tissue prior to placement of the homograft. Middle: Implantation of the aortomitral homograft. Bottom: The completed repair.

Postoperative echocardiography (Figure 2) showed normal aortic valve homograft function and trivial mitral valve regurgitation.

Figure 2. Postoperative echoes showing the position and function of the homograft.

A more satisfactory solution to the ravages of IE

Historically, IE affecting both the aortic and mitral valves has been treated with antibiotics, complete debridement of infected tissue, aortic valve homograft and mitral valve repair or replacement. The IFB, which is inevitably damaged either by the ravages of IE or the radical resection of infected tissue, is reconstructed using either autologous or bovine pericardial tissue.

Dr. Navia’s new surgical technique offers a more satisfactory solution, incorporating tissue of almost the same quality as the resected tissue. It provides resistance to infection and preserves the native mitral valve with its subvalvular apparatus, chordae and papillary muscle. “The incorporated aortomitral homograft reduces trauma and preserves native mitral valve function,” says Dr. Navia. “Results show that it is reliable and safe.”

Twenty-five patients have received the incorporated aortomitral homograft to date, with what Dr. Navia describes as “a good survival curve.” Eighteen of these were reoperations, and four were second reoperations.

Payoffs in high-quality tissue and the native mitral valve

Radical complete debridement of all infected and devitalized tissue is the main principle of surgical treatment of the extensive prosthetic aortic valve endocarditis that involves the IFB and the mitral valve. The goals are to assure secure fixation of the new prosthetic valve and avoid recurrent or residual infection, periprosthetic leak, dehiscence or subannular aneurysm formation. This occasionally leads to resection of the IFB and, consequently, disruption of the fibrous skeleton of the heart, creating a tissue defect that is successfully repaired with an aortic valve homograft and its anterior mitral valve leaflet.

“We recommend consideration of the hemi-commando technique, which provides the advantage of incorporating tissue of almost the same quality as the native tissue,” says Dr. Navia, “and reconstructs the IFB with the invaluable preservation of the native mitral valve.”

Dr. Navia is a member of Cleveland Clinic’s Endocarditis Center, a multidisciplinary team of specialists in infectious disease, cardiology, cardiothoracic surgery, neurology and behavioral health providing comprehensive care for the most complex IE cases.