Aortic Insufficiency in a Patient with Marfan Syndrome after Aortic Root Reconstruction with a Tailored-Sinus Graft

Abstract

A patient with Marfan syndrome underwent valve-preserving aortic root reconstruction with a Robicsek-Thubrikar graft. Intraoperative transesophageal echocardiography showed aortic insufficiency after extracorporeal circulation was discontinued. Placing 3 subcommissural annuloplasty sutures corrected the severe aortic insufficiency. Herein, we discuss the mechanism and prevention of aortic regurgitation after aortic root replacement with a new graft that contains pre-designed aortic sinuses. (Tex Heart Inst J 2003;30:243–5)

Aortic root reconstruction in combination with a valve-preserving procedure is a well-established operation in patients with Marfan syndrome. Preservation of the normal shape and function of the aortic sinuses appears to be important for durability of the aortic valve. The Robicsek-Thubrikar graft with pre-fashioned sinuses can be tailored using a standard Hemashield vascular prosthesis (Meadox Medicals, Inc.; Oakland, NJ). Herein, we describe a patient with severe aortic valve regurgitation and dilatation of the aortic annulus. The aortic regurgitation persisted after the patient was weaned from cardiopulmonary bypass. Slight remodeling of the geometry of the reconstructed aortic root successfully eliminated the regurgitation.

Case Report

A 49-year-old man with Marfan syndrome was referred to our institution. He had striking manifestations of the syndrome, including severe scoliosis and subluxation of both lenses with a lens implant in the right eye. He had cardiomegaly with fusiform dilatation of the ascending aorta, severe aortic valve insufficiency, a flail segment of the posterior mitral leaflet, and anterior mitral leaflet prolapse with severe mitral valve insufficiency. The left ventricular ejection fraction was 0.50. He also had 80% stenosis of the proximal left anterior descending coronary artery, 70% stenosis of the right coronary artery, and 50% stenosis of the 1st obtuse marginal branch. On 10 March 2000, the patient underwent cardiac surgery. A prolapsing section of the posterior mitral leaflet was resected. Chordal transposition was performed from the posterior mitral leaflet to the anterior mitral leaflet. Posterior mitral annuloplasty was performed with a 32-mm annuloplasty strip (CarboMedics Inc.; Austin, Tex). The ascending aortic aneurysm diameter was 5 cm at the sinotubular junction. The diameter at the aortic annulus was 2.7 cm. An aortic valve-preserving procedure was performed, and the aortic root was replaced with a Robicsek-Thubrikar graft (Fig. 1) that had been tailored preoperatively for our patient. We cut 3 precisely measured rectangular pieces to make individual sinuses and created the neo-sinotubular junction by sewing the individually made sinuses to 1 end of a Hemashield graft using a fluted template and 4-0 Prolene suture. ¹ The right and left coronary arteries were reimplanted. Coronary artery bypass was then performed. Saphenous vein grafts (SVGs) were placed to the left anterior descending and right coronary arteries, and to the 1st obtuse marginal branch. Both internal thoracic arteries were damaged from previous chest wall trauma. Intraoperative transesophageal echocardiography showed moderately severe aortic insufficiency. The regurgitant jet was central and resulted from malcoaptation of all 3 aortic cusps. Cardiopulmonary bypass and cardiac arrest were reinstituted. The aorta was reopened, and 3 commissuroplasty sutures were applied using 4-0 Prolene in a mattress arrangement underneath the commissures (Fig. 2). Thus, the newly created artificial sinuses were approximated, and the aortic insufficiency was reduced to mild. The patient was doing well 3 years after surgery. He remained in NYHA functional class I and had mild aortic insufficiency as evaluated by echocardiography.

Fig. 1 Aortic root replacement with Robicsek-Thubrikar graft in combination with coronary artery bypass operation.

Fig. 2 A) Aneurysmal dilatation of sinotubular (ST) junction and aortic annulus (AA) ectasia in a patient with Marfan syndrome. B) Restoration of normal ST junction diameter with remaining aortic annulus ectasia after aortic root replacement with the Robicsek-Thubrikar graft. C) Restoration of normal diameter of the aortic annulus by use of 3 commissuroplasty sutures placed to approximate the artificial sinuses of the graft and to reduce the aortic annulus.

Discussion

It is crucial to foresee the changes in degree of the aortic annular expansion and in root geometry after aortic root surgery. ^1,2 It is just as important in aortic root reconstruction combined with a valve-preserving procedure as it is in root replacement with a homograft. Although aortic root replacement with a homograft is a nearly perfect geometric reconstruction, long-term homograft durability is limited because of the lack of viability. This results in a significant structural failure rate during the 2nd decade after implantation. ³ Therefore, preserving the native aortic valve is important for valve longevity. Ideally, aortic root reconstruction in Marfan syndrome should preserve the native aortic valve, prevent further annular dilatation, and re-create the natural shape of the aortic root—the aortic sinuses in particular. Another consideration is the aneurysmal spread of the sinotubular junction, which is a common mechanism of aortic insufficiency in Marfan syndrome. ⁴ This can be accompanied by annular dilatation (Fig. 2A). Failure to reduce the diameter of the dilated aortic annulus can result in severe aortic insufficiency despite restoration of the normal sinotubular junction diameter (Fig. 2B). Indeed, a univariate analysis of 71 patients (including 20 patients with Marfan syndrome) who underwent valve-preserving aortic root reconstruction at Mayo Clinic showed that an aortic annulus size of more than 25 mm was a predictor for subsequent aortic valve replacement. ⁵ Large annulus size has not presented a major problem with valve-sparing aortic root reconstruction techniques as described by Yacoub's ⁶ and David's ⁷ groups, because reconstruction with a rigid conduit implanted in the subcoronary area effectively reduces the diameter of the annulus. Moreover, the early and long-term results of valve-preserving operations for patients with Marfan syndrome are encouraging. ⁸ However, the valve-preserving operations pioneered by Yacoub ⁶ and David ⁷ do not re-create functional aortic sinuses; therefore, in both of their techniques, the function of the aortic sinuses and the aortic root, as a whole, is compromised. The importance of the aortic sinuses for the function and longevity of the aortic valve has been recognized. ⁹ The 1st clinical experience with the Robicsek-Thubrikar graft was reported previously. ¹⁰ This novel prosthesis not only re-creates the normal shape of the aortic sinuses but also allows the sinuses to spread apart to a greater extent in both systole and diastole. As such, the graft does not provide a rigid support to tighten the aortic annulus at the subcoronary level. It is crucial, therefore, to reduce the diameter of the aortic annulus to normal at that level. This can be accomplished by placing 3 annuloplasty stitches as described in our report (Fig. 2C).

In summary, implantation of the new graft with pre-fashioned aortic sinuses results in nearly normal aortic root geometry. However, in patients with dilatation of the annulus, the placement of subcommissural annuloplasty sutures appears to be necessary to avoid splaying of the sinuses and the resultant central aortic insufficiency.