Ann Thorac Surg 1997;63:559-560
© 1997 The Society of Thoracic Surgeons
Case Report
Technique for Reconstruction of the Sinotubular Junction
Gopal Bhatnagar, MD,
George T. Christakis, MD,
Patricia M. Murphy, MD,
Donald Oxorn, MD,
Bernard S. Goldman, MD
Divisions of Cardiovascular Surgery and Anesthesia, Sunnybrook Health Science Centre, University of Toronto, Toronto, Ontario, Canada
Accepted for publication September 26, 1996.
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Abstract
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Correct geometric relationships between the annulus and sinotubular junction during stentless valve implantation are critical to minimize the development of insufficiency. Some patients with aortic valve disease have dilatation of the sinotubular junction and are unable to have a stentless valve placed by standard techniques. We recently encountered such a patient and reconstructed the sinotubular junction by aortic crenation. Multiple interrupted plicating sutures were used to reduce the aorta from a diameter of 42 mm to 28 mm. This method allows tailoring of the aorta to appropriate size by varying the number of crenating sutures.
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Introduction
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The development of the stentless bioprosthesis for aortic valve replacement has provided a readily available alternative to homograft and stented valves [1–3]. Although the stentless bioprosthesis has superior hemodynamics compared with a stented prosthesis [3, 4] and theoretic advantages in terms of left ventricular remodeling [4–6], the relationship between the valve annulus and the sinotubular junction (STJ) is an important factor in determining long-term competence [1, 5, 7–10]. In some instances patients who may otherwise be candidates for a stentless valve receive a stented valve because of large discrepancies between annular and sinotubular size [11].
Recently a 78-year-old woman with class III symptoms referable to her aortic stenosis was accepted for Stentless Porcine Valve (SPV) placement (Toronto SPV; St. Jude Medical, St. Paul, MN). Transesophageal echocardiography, however revealed an indistinct native STJ judged to be 29 mm, whereas the annulus was 27 mm. Additionally, the distance between the valve annulus and the presumed STJ was short, with the aorta above rapidly expanding to 42 mm. Intraoperative sizing revealed an enlarged STJ at 30 mm and an annulus appropriate for a 29-mm SPV. We decided to place the SPV and reconstruct a sinotubular junction as the patient had marked left ventricular hypertrophy and she required the maximum relief from left ventricular outflow tract obstruction that a bioprosthesis could provide. Complete aortic reconstruction or replacement was not considered as the maximum diameter was 42 mm and it was thought that potential morbidity would be high.
Aortic cannulation was carried out toward the lesser curvature of the aorta close to the inominate artery takeoff, allowing a high aortotomy to be performed. Careful dissection of the pulmonary artery from a generous portion of the aorta was carried out with particular attention to the left mainstem origin. Anteriorly the root of the aorta was dissected until the takeoff of the right coronary artery was identified. After aortic cross-clamping, a transverse aortotomy was performed high enough above the right coronary artery takeoff to accommodate the SPV commissural posts and approximately 5 to 6 mm above the native STJ. The cut was made in a plane perpendicular to the direction of the aorta and carried down until only 2 cm of aorta remained in continuity posteriorly. The 29 mm valve was implanted using the standard techniques as described elsewhere [2, 4, 7]. Remodeling of the sinotubular junction was carried out during aortotomy closure (Fig 1
). Plicating sutures were placed using 4-0 Prolene (Ethicon, Somerville, NJ), with each suture visually judged to crenate approximately 5 mm of aortic wall. Initially the aortotomy was bisected and each half of the remaining aortotomy was again bisected. No pledgets were used for the interrupted horizontal mattress plicating sutures. The aortotomy closure was initiated as a plicating suture using a Teflon pledgeted 4-0 Prolene suture and was performed using a two-layer McGoon-type closure (horizontal mattress with an over-and-over whip suture). A total of five plicating sutures were placed on each side of the aortotomy.
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Fig 1. . Aortotomy closure with plicating horizontal mattress sutures is used to recreate a narrower sinotubular junction. The value commissural posts have been omitted but would extend to within 5 mm of the aortotomy.
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Transesophageal echocardiography was carried out after separation from bypass, and the remodeled STJ was clearly visible, measuring 28 mm. This neo-STJ represented the crenated aorta, which originally measured 42 mm. The diameter of the aorta above the plication remained 42 mm. No aortic insufficiency was observed on color Doppler echocardiography.
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Comment
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In normal human aortic root measurement studies the STJ is approximately 20% smaller than the annulus [10]. Aortic valve stenosis often results in loss of this relationship, with dilation of the STJ [3]. Consequently patients who otherwise may benefit from an SPV become ineligible. Aortoplasty can be used to remodel the STJ to restore an acceptable geometric relationship, minimizing the risk of late valvular insufficiency. Plication may be accomplished in the noncoronary sinus of Valsalva; however, the more friable tissue of the sinus requires reinforcement and may result in hemorrhage. The use of a pericardial strip one third the diameter of the implanted valve sizer may be used to reinforce this type of remodeling when one sinus is asymmetrically dilated. By using interrupted sutures, each accomplishing 4 to 6 mm of crenation, the stress is more evenly distributed. Additionally, sutures are placed in a generally more sturdy aortic wall.
Postoperative transesophageal echocardiographic measurement of the remodeled STJ revealed a diameter of 28 mm, a 33% reduction from the preoperative measurement. The amount of plication can be tailored to achieve a desired STJ diameter based on geometric relationships. Because the largest available SPV is 29 mm, patients with an STJ greater than 31 mm (10% greater than the annulus) are not geometric candidates for an SPV. Assuming an initial STJ of 32 mm (circumference of 100 mm), the use of five plicating sutures each taking up 4 mm of aortic circumference would leave an STJ 26 mm in diameter (circumference, 80 mm). This results in an STJ 20% smaller, potentially improving long-term competence of the valve. The use of the McGoon closure further complements the aortoplasty and provides a reliable hemostatic closure.
This technique may also be applicable for patients in whom the STJ far exceeds the size of the annulus, although both are less than 29 mm. The valve appropriate to the annulus may be placed while the STJ is remodeled to be 20% less than the annulus. Patients with annuloaortic ectasia or systemic connective tissue diseases with indications for aortic replacement should be excluded from plication techniques. This technique may provide a useful tool for surgeons who implant valves; it can be used when sinotubular discordance otherwise prohibits stentless valve insertion.
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Footnotes
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Address reprint requests to Dr Bhatnagar, Division of Cardiovascular Surgery, Sunnybrook Health Science Centre, 2075 Bayview Ave 429, Toronto, ON, M4N 3M5, Canada.
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References
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Abstract
Introduction
