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Interact CardioVasc Thorac Surg 2009;8:187-190. doi:10.1510/icvts.2008.187633 © 2009 European Association of Cardio-Thoracic Surgery
Aortic root reconstruction using new vascular graft
a Department of Cardiovascular Surgery, Cardiovascular Center Bad Neustadt, 97616 Bad Neustadt, Germany Received 7 July 2008; received in revised form 29 October 2008; accepted 3 November 2008
1 Dr Urbanski discloses a financial relationship with InterVascular, Inc.
The aim of this study was to determine the feasibility of the new vascular graft for aortic root reconstruction using two different surgical techniques and to evaluate the intermediate clinical and functional results. Between January 2006 and December 2007, a total of 79 patients with aortic root and valve pathologies (chronic aneurysm 70, acute aortic dissection 9) underwent valve-sparing aortic root repair at our facility. Moderate to severe (3+) or severe (4+) aortic regurgitation was present in 19 (24%) and 7 (9%) patients, respectively. A new vascular aortic root graft was used in all patients. The 30-day mortality was zero. The aortic valve had to be replaced before discharge due to recurrent insufficiency in one patient. In all remaining patients, the postoperative echocardiography at discharge showed no, trivial, or mild insufficiency in 61, 15 and two patients, respectively. During the follow-up time, which was completed for all patients and averaged for repair survivors 15±7 (range, 6–29 months), these echocardiographic findings remained unchanged. The new vascular aortic root graft is feasible for aortic root reconstruction using both reimplantation technique and single patch remodeling technique. It provides very good surgical handling and leads to excellent early and intermediate functional results.
Key Words: Aortic valve; Valve repair aortic root; Aortic aneurysm
Because valve-sparing aortic root repair techniques are gaining increasing acceptance in aortic root surgery, a continuous development of different surgical methods and their modifications has been noticed. Special vascular root grafts have even been proposed for improving the surgical functional results [1, 2]. The prosthesis presented here, which has been described in previous publications, is yet another new vascular graft designed for aortic root repair [3, 4]. The new aortic root graft (InterGard Woven Aortic Thoracic Graft; InterVascular, La Ciotat, France), designed by the author (PU), is a collagen-coated woven polyester tube that has a 3-cm-long uncrimped proximal part intended for repairing the aortic root. The aim of this prospective observational study was to determine the feasibility of the new vascular graft for valve-sparing aortic root repair using two different surgical techniques and to evaluate the mid-term functional results after all procedures in which the graft was used.
Between January 2006 and December 2007, a total of 79 patients underwent aortic root repair at our facility. All patients suffered from aortic root disease, such as chronic aneurysm (70) or acute aortic dissection (9), combined with aortic valve insufficiency in 75 cases. Moderate to severe (3+) or severe (4+) aortic regurgitation was present in 19 (24%) and 7 (9%) patients, respectively. The detailed patient data are given in Table 1.
All patients were operated on using the new aortic root graft. In patients in whom all three sinuses had to be replaced the single patch technique was used (10), as is our routine; however, reimplantation technique was used in five selected patients for demonstration purposes [4]. In the remaining patients, only one sinus (41) or two sinuses (23) were replaced using the single patch technique. Nevertheless, a total of 35 patients (44%) needed additional procedures on the valve cusps (Table 1).
To choose the proper aortic graft size, the aortic annulus was measured with a valve sizer and defined as the same size as the biggest sizer that could pass through the aortic valve. Because in bicuspid valves and in patients with septum hypertrophy this is not possible, the sizer was only placed on the valve and the appropriate size was judged visually. The diameter of the graft used for aortic root repair with valve reimplantation technique was approximately 5 mm bigger than the diameter of the aortic annulus. The surgical procedure followed the steps described by David and Feindel in their original article [5]. The aortic remnants, including valve commissures, were placed within the uncrimped part of the graft and fixed to the tube with a 5-0 polypropylene continuous suture. It is actually this very important step of valve reimplantation that is simplified by using the new graft with an uncrimped proximal part. The valve remnants adhere to the smooth surface of the graft; this ensures their proper location and allows very easy sewing without the need to stretch the tube tautly, which is necessary to achieve appropriate commissure height when a standard crimped graft is used. After reimplanting the coronary ostia and before completing the procedure by anastomosing the graft to the distal ascending aorta, the tube was narrowed at the level of the sino-tubular junction with additional U-stitches between the tops of the commissures, and if it was necessary, the caliber of the graft above the sino-tubular junction was gradually narrowed distalwards by excising a triangle and re-sewing the graft with a 4-0 polypropylene continuous suture. For aortic root repair using single patches, the tube with the same diameter as the aortic annulus or 1 mm bigger was chosen. This surgical procedure has been described previously [6]. Depending on the number of sinuses that had to be replaced, one to three patches were excised from the uncrimped part of the tube and trimmed to teardrop shapes compatible with the size of the respective valve cusps. Cutting the patches from the uncrimped tube facilitates the determination of the proper size and shape of the patches and improves the tightness of the suture line by eliminating leaks between the folds of Dacron (Fig. 1). The patches were sewn to the rim of the aortic wall with a 5-0 polypropylene running suture, and coronary buttons were reimplanted in cases in which the coronary sinuses were replaced.
Several additional procedures on the cusps such as free margin reinforcement, cusp patch plasty, or others, completed the aortic root repair regardless if it was reimplantation or a single-patch procedure (Table 1).
The mean cross-clamp time, including the circulatory arrest period, was 105±30 min and ranged from 50 min for isolated aortic root repair to 173 min for a complex aortic root and valve repair, and intraoperative re-repair after echocardiographic control revealed that a correction was necessary. Even though all additional cardiac and aortic arch procedures were performed in the single-patch-technique group exclusively, the mean cross-clamp time for these patients was shorter (103 vs. 130 min). The 30-day mortality was zero, and the rate of permanent neurologic complications was 1.3% (minor stroke in one patient). There were also two transient neurologic deficits (2.5%); however, all neurologic complications occurred only in patients with acute aortic dissection. As mentioned above, a second run was necessary in one patient after complex aortic root and valve reconstruction with replacement of all three sinuses using single patches and cusp repair, which led to a very successful result without any residual insufficiency. In another patient, also after a complex root and valve reconstruction, the valve had to be replaced before discharge due to recurrent insufficiency. In all remaining patients, the postoperative echocardiography at discharge showed no, trivial, or mild insufficiency in 61, 15, and two patients, respectively. The restoration of the aortic root that perfectly fits the patient's anatomy could be achieved in all operated patients, especially gratifying in the patients in whom all three sinuses were replaced (Figs. 1 and 2). During the follow-up time, these echocardiographic findings remained unchanged in all patients. There were four late deaths (all not-procedure-related) during the follow-up, which was completed for all patients and averaged 15±7 (range, 6–29) months for repair survivors.
During the process of dilatation, the sinuses change their dimensions in the transverse as well as longitudinal axis; moreover, these changes are pronounced differently in the separate sinuses. The correct positioning of commissures in regard to their height and the distance to each other is therefore of utmost importance for successful aortic root repair. Because the primary functional results after aortic valve repair are prerequisite for a long-lasting competent valve [6], the surgical technique ought to be as simple as possible to ensure the proper anatomy of the valve remnants within the reconstructed aortic root. In addition, it should allow easy evaluation of the valve cusps and facilitate their repair because additional procedures on the valve cusps to restore their correct coaptation are very often necessary in aortic root pathologies. The single patch technique described by the author (PU) previously, offers the possibility of a case-based, individualized reconstruction of the sinuses of Valsalva and replacement of only the distorted sinuses, which allows the normal sinuses to remain untouched [7, 8]. The use of the uncrimped part of the graft for the patches facilitates the determination of the proper size and shape of the neo-sinuses because they change their form after stretching, even considerably, regardless whether the crimping of the Dacron is oriented longitudinally or transversally. Because the sum of the sinuses' widths has to be equal to the circumference of the tube graft chosen for aortic replacement and the proper sizes and shapes of neo-sinuses can only be judged visually, it makes sense to cut the patches from the uncrimped part of the tube rather than from a loose sheet of uncrimped Dacron. In our opinion, the original Yacoub remodeling technique [9] hardly allows any corrections of commissural location during suturing, and cusp repair is complicated by the deep location of the valve inside the tube. Although in experienced hands the Yacoub method offers favorable results in selected patients [10] and can also be used in patients in whom just selected sinuses have to be replaced [11], we do not use this technique in our surgical practice; consequently, the current series does not contain any patients operated on using the original remodeling technique. However, if only in theory, the Yacoub method would be easier if the graft were not crimped because determining the proper size and form of the tongue-shaped tube's edging would be facilitated. On the other hand, the David reimplantation technique allows corrections of the height and distance between commissures at any time during the fixation of the valve remnants within the tube. Further advantages of this procedure are very good hemostatic characteristics and stabilization of the annulus through the subannular sutures, which is especially important in cases with annulus dilatation such as in Marfan patients. However, this technique is very complex and always associated with reimplantation of coronary arteries; although, in many patients with aortic root dilatation, whether or not accompanied by an aortic valve insufficiency, replacement of all three sinuses is not necessary, as demonstrated in our series in which fewer than 20% needed three sinuses replaced. Nevertheless, in patients in whom all three sinuses have to be replaced, the reimplantation technique, which is familiar to and preferred by many surgeons, is an excellent option. Among 79 patients who underwent valve-sparing aortic root repair at our facility during the past two years, we selected five cases, mostly during aortic root surgery workshops, to demonstrate the suitability of the new aortic root graft also for the reimplantation technique in which the restoration of the aortic root anatomy that perfectly fits the patient's anatomy could be achieved in all operated patients despite the straight form of the graft [4]. In comparison to other commercially available aortic grafts, the described prosthesis considerably facilitates reimplantation of the aortic valve inside the tube because the standard crimped graft has to be stretched very tautly for correct placement of the valve remnants as well as also for each stitch during sewing. For this reason, evaluation of the valve position inside the crimped graft, especially in regard to proper commissure height, is not easy and associated with a risk of incorrect fixation of the valve inside the tube. Using the new aortic root graft for reimplantation allows easy suturing of the valve remnants inside the uncrimped part of the tube and facilitates the determination of the proper commissure height. The ‘Valsalva graft’ [1], another vascular prosthesis for aortic root surgery, also closely mimics the human's root anatomy; however, its use in patients in whom the root geometries have already changed can present difficulties [12, 13]. Since the dimensions of the Valsalva graft are predetermined, the individual anatomy of the patient has to be adapted to the tube in order to place the tops of the commissures exactly at the level of the sino-tubular junction, and if the patient's commissures have a different height, which is not uncommon, it can be even impossible. However, if the geometry of the valve is not altered, the tops of the commissures are located at the same height and there is no pathology of the cusps to be repaired, use of Valsalva graft can provide favorable results as presented by the group from Baltimore that implanted the Valsalva graft in 51 very select patients with aortic root aneurysm but without concomitant aortic valve insufficiency [14]. However, in many patients with aortic root disease, especially in those with aortic insufficiency, additional procedures on the valve cusps are necessary and these, often very complex procedures, are difficult to perform when access to the valve cusps is not optimal or even limited by the depth of the tube graft. In conclusion, the new aortic root graft offers very good handling for aortic root reconstruction using both single patch and reimplantation techniques. Its use leads to the simplification of these challenging procedures and provides favorable operative and early postoperative results.
The authors would like to thank Mrs Melissa Lindner, Mrs Alexandra Metz, and Mrs Bianca Müller for preparing this article.
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Abstract
1. Introduction
