Modified David With a Valsalva Graft

In this video, the authors present the case of a 40-year-old man who underwent reimplantation of the aortic valve with replacement of the ascending aorta and proximal aortic arch one year after percutaneous implantation of a vascular stent into the descending aorta to correct a coarctation. A recent follow-up CT scan had shown a rapid and progressive dilatation of the ascending aorta, up to 53 mm, with indication for surgical correction. The preoperative coronary angiography was unremarkable, with the exception of a separate origin of the anterior descending and circumflex coronary arteries.The intervention was accomplished via a median sternotomy, and cardiopulmonary bypass was instituted by cannulation of the distal ascending aorta and right atrium. Del Nido cardioplegia was delivered both in antegrade and retrograde fashion. Transesophageal eco confirmed a tricuspid aortic valve with mild regurgitation.

After aortic cross clamping and transection, the authors were confronted with features typical of an acute dissection involving the whole of the ascending aorta. Sample tissue was sent for histological examination but failed to reveal any pathological predisposing factor. The authors then proceeded with careful dissection of the aortic root, aiming to perform a David procedure. The coronary ostia were trimmed and the three commissures suspended with traction stitches. The Valsalva’s sinuses were trimmed along the cuspid insertion line, leaving no more than 2-3 mm of residual margin. The aortic annulus was sized and a 30 mm Valsalva graft was selected, taking into account that usually, a graft diameter in excess of 4 to 5 mm is adequate. The measurement of cups height is of the utmost importance, as described later.

A series of “U” stitches were passed from the ventricular aspect outside the aorta, just beneath the cusps insertion, taking care to avoid damaging the atrioventricular node below the right noncoronary commissure. Subsequently, the same stitches were passed through the collar of the graft, and the graft itself reduced in height. The three traction commissural stitches were threaded through the conduit before lowering it in the final position. Once the internal temperature of 26 °C was reached, the authors proceeded to circulatory arrest and removal of the aortic cross clamp and arterial cannula. The distal part of the ascending aorta and the proximal hemi-arch were resected with no evidence of intimal tear causing dissection. Antegrade cerebral perfusion was initiated via innominate and left carotid arteries cannulation. A 28 mm vascular graft was anastomosed distally, securing it with a teflon felt outside the native aortic arch, avoiding any interference with the stent previously implanted in the descending aorta. Following insertion of the arterial cannula through a side branch vascular graft, the anastomosis was completed. Cerebral perfusion cannulas removal and de-airing allowed to re-start systemic perfusion and simultaneous rewarming. The authors subsequently proceeded to tie, by means of Cor-Knot® Device (LSI Solutions, Victor, NY 14564, USA), the stitches previously threaded through the graft base, keeping in situ a 26 mm Hegar dilator to prevent a purse string effect on the aortic ring.

Finally, the three commissures were suspended inside the proximal portion of the Valsalva graft seeking to reproduce the most appropriate native root geometry. An empiric qualitative evaluation of the aortic valve competence was tested. The coronary ostia were subsequently anastomosed to the new root and the proximal and distal vascular grafts were connected by a termino-terminal anastomosis. Intraoperative transesophageal echocardiography demonstrated a good operative result with mild residual aortic regurgitation. The operation was then completed in the conventional manner.

Conservative surgery of the aortic valve has a long history, dating back to 1913, when Tuffier performed the first commissurotomy. Careful assessment of the surgical aortic valve anatomy and precise analysis of the underlying pathology are the essential prerequisites for a successful procedure. In 1992, a new surgical remodeling technique was introduced by Tirone David (1) for the treatment of aortic valve incompetence secondary to aneurysmal dilatation of the ascending aorta. Subsequently, it became evident that aortic valve incompetence could develop at a later stage even in patients needing aortic remodeling in the presence of a normal size annulus. For this reason, re-implantation of the native aortic valve in a cylindrical graft was later introduced and has been used extensively with excellent long-term results. However, an unnatural geometry, due to absence of sinuses, leads to flawed hemodynamics generating uneven stress distribution eventually leading to progressive fibrosis and calcification of the cusps. This concept is amply shown with the different long-term durability in valve repair and reconstruction. Accordingly, the presence of aortic sinuses is important for aortic cusp motion and reduction of cusp stress, consequently shortening opening and closure velocity (2).

In this case, the decision to use a Valsalva graft, in which the height of the sinus portion of the graft is equal to its diameter, was dictated essentially to preserve the physiologic movement of the aortic cusps and restore the most faithful anatomy (3). As described and reported by El Arid (4), a single suture of the Valsalva graft at the level of the ventriculo-aortic junction spares the suture line inside the aortic root, with the advantage of shortening the cross clamp time.

References

1. David T, Fiendel CM. An aortic valve-sparing operation for patients with aortic incompetence and aneurysm of the ascending aorta. J Thorac Cardiovasc Surg. 1992;103:617-621.
2. Leyh RG, Schmidtke C, Sievers HH, Yacoub MH. Opening and closing characteristics of the aortic valve after different types of valve-preserving surgery. Circulation. 1999:100:2153-2160.
3. De Paulis R, De Matteis GM, Nardi P, Scaffa R, Buratta MM, Chiariello L. Opening and closing characteristics of the aortic valve after valve-sparing procedures using a new aortic root conduit. Ann Thorac Surg. 2001;72:487-494.
4. El Arid JM, Azzaoui R, Koussa M, Modine T. A technique to facilitate the native valve reimplantation during the David procedure. J Card Surg. 2014;29:485–486.

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