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Ann Thorac Surg 2007;83:S752-S756
© 2007 The Society of Thoracic Surgeons
Clinic of Cardiac Surgery, University Clinic of Schleswig-Holstein, Campus Luebeck, Luebeck, Germany
* Address correspondence to Dr Sievers, Clinic of Cardiac Surgery, University Clinic of Schleswig-Holstein, Campus Luebeck, Ratzeburger Allee 160, 23538 Luebeck. (Email: herzchir{at}medinf.mu-luebeck.de).
Presented at Aortic Surgery Symposium X, New York, NY, April 27–28, 2006.
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Abstract |
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 Top Abstract IntroductionPatients and MethodsResultsCommentAcknowledgmentsReferences |
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METHODS: Between July 1993 and July 2005, 164 consecutive patients were operated on using the remodeling (group A, n = 96) or reimplantation technique (group B, n = 68). Fifty-seven patients presented with acute type A dissection. Aortic regurgitation was present in 84%. Follow-up was 54.7 ± 28 in group A and 48.4 ± 37.3 months in group B.
RESULTS: After urgent operations, 4 patients died in each group, but none died after elective surgery. Late mortality was 8% in group A and 4% in group B. Seven patients of group A and 1 in group B required reoperation. Echocardiographic follow-up of reoperation-free survivors showed that 3 patients (all group A, 1.3%) had aortic regurgitation of more than grade II. Root diameter, valve pressure gradient, and valve orifice area were comparable. No gross thromboembolic or bleeding events occurred.
CONCLUSIONS: Aortic valve–sparing operations can provide acceptable long-term results in both techniques. Particular care to the annulus in the remodeling technique and different prosthesis designs in the reimplantation technique may overcome the intrinsic problems of each procedure.
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Introduction |
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TopAbstractIntroductionPatients and MethodsResultsCommentAcknowledgmentsReferences |
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To provide an alternative, valve-preserving techniques have been introduced in recent years. The first was the remodeling technique described by Yacoub and colleagues [4], which replaces the sinuses separately, and later the reimplantation technique of David and Feindel [5], which replaces the entire wall of the aortic root with a straight prosthetic tube. Both techniques are reported to provide excellent functional results, with a low pressure gradient and no or minimal aortic regurgitation [6–10].
Reimplantation of the aortic valve in a rigid tube leads to a nonphysiologic movement of the valve leaflets similar to that observed for stented bioprotheses, exposing the leaflets to increased bending stresses and thus to the risk of premature failure. Remodeling of the aortic root preserves some distensibility, with the propensity to reduce aortic outflow resistance and thus to lessen the load on the ventricle. It further allows for creation of a pseudosinus, allowing nearly normal opening and closing characteristics of the aortic valve and enhancing its durability [11, 12].
Nevertheless, debate still exists about which technique to apply to different pathologic conditions and, more generally, what there is to gain from using valve-sparing techniques compared with the standard composite prostheses. We therefore reviewed our 10-year experience with both types of valve-preserving techniques.
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Patients and Methods |
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TopAbstractIntroductionPatients and MethodsResultsCommentAcknowledgmentsReferences |
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Between July 1993 to July 2005, 164 consecutive patients underwent aortic valve–sparing operations in our institution. The Yacoub remodeling technique was used to treat 96 patients (group A), and 68 patients were treated with the reimplantation technique (group B) described by David. Patient records and the clinical database were reviewed retrospectively. Preoperative patient characteristics are summarized in Table 1.
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Aortic valve–sparing procedures were performed when the cusps appeared macroscopically intact. The aortic valve was preserved in 18 patients even though a bicuspid valve was present. The choice of the preserving technique was based on the surgeon’s preference and not on details of the pathologic process. However, in light of increasing evidence that stabilization of the aortic root annulus may be of importance for long-term aortic root durability in patients with acute type A aortic dissections and in those with Marfan syndrome, it is the policy in our clinic to perform the reimplantation technique in patients with these pathologies [13–15].
Operative Technique
After median sternotomy, standard cardiopulmonary bypass was initiated with a membrane oxygenator (Hollow Fiber Oxygenator, Spiral Gold, Baxter, Puerto Rico) using antegrade crystalloid or blood cardioplegia. Profound hypothermia (15° to 18°C) was used when circulatory arrest was necessary. The side of arterial cannulation was the femoral artery in 32 patients, the right subclavian artery in 5, a combination in 6, and the ascending aorta in a nondissected area in 121. Venous cannulation was performed through the right femoral vein in 9 patients and through the right atrium in the rest.
The operative technique of the remodeling technique (group A) and the reimplantation technique (group B) has been described in detail [4, 5]. Briefly, the ascending aorta was transected 3 mm above the commissures. The sinuses of Valsalva were excised, leaving a 2-mm rim attached to the crown-shaped annulus. If the dissection affected the aortic root, gelatin-resorcin-formaldehyde glue (GRF; Cardial, Saint E'tienne, France) was used to readapt the dissected layers of the aortic wall before the sinuses were excised. The size of the tube used was determined by the distance between the straightened commissures giving a macroscopic picture of appropriate cusps coaptation and the diameter of the base of the aortic annulus, measured by means of a Hegar dilator [16].
According to the adopted procedure, a trimmed or straight Hemashild Gold tube (Meadox Medicals, Oakland, NY), made with Dacron (DuPont, Wilmington, DE), was used to replace the excised sinuses. In some patients, one or more of the sinuses were macroscopically intact without any changes of the underlying pathology; only one sinus was replaced in 13 of these patients, and in 5 patients only two of the three sinuses were replaced using the surgical principles of the remodeling technique. In some patients of the remodeling group, we used our own technique of individual replacement of each sinus with a single piece of Dacron tube and additional replacement of the ascending aorta.
In most of the patients, the distal anastomosis was performed in an open fashion using circulatory arrest. A hemiarch replacement was necessary in 47 patients, and the entire arch was replaced in 8 patients. Intraoperative data are summarized in Table 2.
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Postoperative Management
Each patient was prescribed ß-blocker and aspirin therapy for anticoagulation postoperatively. Antibiotic prophylaxis for endocarditis was recommended, following the guidelines of the German Society of Cardiology [17].
Echocardiographic Data Acquisition
An echocardiogram was obtained in each patient in the early postoperative course and at follow-up in our department using a Hewlett-Packard Sonos 2500 system with 2.5- and 5.0- MHz ultrasound transducers (Palo Alto, CA). Conventional continuous-wave and pulsed-wave Doppler as well as color-flow Doppler techniques were applied in the standard transthoracic and transesophageal views. Calculations of ejection fraction, cardiac output, stroke volume, and transvalvular pressure gradient were performed according to our previous description [18].
Aortic regurgitation was assessed by color-flow Doppler techniques according to the ratio of jet height/left ventricular outflow tract height as described by Perry and colleagues [19], with a ratio of 1% to 24% as grade I, 25% to 46% as grade II, 47% to 64% as grade II, and more than 65% as grade IV.
Statistical Analysis
For statistical analysis, the Mann-Whitney U test, Fisher exact test, and the Kruskal-Wallis H test were used. Reoperation rates and patient survival were analyzed using the Kaplan-Meier method. All tests were two-sided. Dichotomous variables are presented as absolute numbers and relative frequencies. Because some variables were not normally distributed, continuous data are given as median (minimum-maximum). A value of p 
0.5 was considered to be statistically significant. All tests were performed using SPSS 9.0 (SPSS Inc, Chicago, IL).
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Results |
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TopAbstractIntroductionPatients and MethodsResultsCommentAcknowledgmentsReferences |
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Follow-Up
Follow-up data in survivors were completed in 143 patients (98.6%). Mean follow-up was 54.7 ± 28 months (range, 0.2 to 113 month) in group A and 48.4 ± 37.3 months (range, 0.3 to 153 month) in group B. During follow-up, 8 patients died in group A (9% of survivors) and 3 patients in group B (5% of survivors). Thus, overall mortality was 12.5% in group A and 10.3% in group B. Freedom from reoperation was 89% ± 4% after 55 ± 28 months in group A and 98% ± 2% after 49 ± 37 months in group B (Fig 1).
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One patient in group B underwent reoperated due to valve degeneration. None of the patients reported clinically relevant thromboembolic or bleeding events. None of the patients underwent reoperation because of acute aortic valve endocarditis.
Echocardiographic Data
Echocardiographic data are presented in Table 3. Only 1.3% of the remodeling group, and no patient in the reimplantation-group, had aortic valve insufficiency exceeding grade II at last follow-up.
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Comment |
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TopAbstractIntroductionPatients and MethodsResultsCommentAcknowledgmentsReferences |
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Several authors report very low hospital mortality rates for valve-preserving root replacement [6, 8–10, 20]. This indicates that these procedures can safely be performed with results comparable with composite graft replacement, at least in patients with aortic root aneurysms [21]. The hospital mortality in type A aortic dissection in our series is 14.3% and comparable with composite replacement reported by other authors [22, 23]. Other variables, such as the clinical condition of the patient, especially the presence of circulatory shock, are known predictors of death after this operation. There was no difference in hospital mortality between the valve-preserving techniques.
Reoperations were required in 7 of 96 patients in whom a remodeling technique was performed, compared with 1 of 68 patients in the reimplantation group. In patients undergoing reoperation in the remodeling group, it is not clear whether GRF glue that was used during the primary intervention had influenced tearing of the sutures from the commissures or whether the glue itself caused some weakness of the tissue. The reasons for the reoperations, therefore, are speculative; however, the higher stress on the suture line in the remodeling technique compared with the reimplantation technique may have had some impact.
Other groups have also found a somewhat higher, albeit statistically insignificant, reoperation incidence after the remodeling technique in type A dissection. One should take care to stitch the annulus when performing the remodeling technique in acute type A aortic dissection, especially at the often-dissected commissure between the noncoronary sinus and the left coronary sinus, or to opt for the reimplantation technique in these more seriously damaged roots.
No serious thromboembolic or bleeding events occurred in either group, comprising 670 patient-years of follow-up. These observations seem to point to a clear advantage of the valve-preserving technique. There is strong evidence that aortic valve–sparing operations offer an excellent alternative to the composite replacement owing to the lower risk of thromboembolic and bleeding events.
Different pathologies of the aortic root require different surgical strategies, however. In patients with aortic root aneurysms, we believe that the annular diameter determines which procedure preserves the aortic root better in the long term. A larger diameter should be treated with the reimplantation procedure or with a comparable technique that secures the aortic root at the aortoventricular junction. Smaller aortic roots may benefit from the remodeling technique, because we and others have shown that aortic root dynamics are more physiologic with the remodeling technique [11, 18]. The exact diameter at which either technique can be performed with comparable long-term results is unknown. In our opinion, patients with type A aortic dissection and Marfan syndrome represent two other pathologic conditions that may benefit more from the reimplantation technique because of its greater support for the aortic annulus.
In conclusion, both valve-sparing techniques represent an attractive alternative to composite grafts, and both strategies have pros and cons regarding aortic root physiology and aortic root support. We believe that pathologies with impairment of the root integrity, as found in Marfan syndrome, acute type A aortic dissection, and excessive annular dilatation, may benefit from annular support. For these patients, we prefer the reimplantation technique. In patients with absent or moderate annular dilatation, however, a remodeling technique is our surgical strategy because the dynamics of the aortic root are better preserved; this has theoretic advantages for long-term valve performance.
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Acknowledgments |
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TopAbstractIntroductionPatients and MethodsResultsCommentAcknowledgmentsReferences |
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References |
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TopAbstractIntroductionPatients and MethodsResultsCommentAcknowledgmentsReferences |
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This article has been cited by other articles:
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  F. Roubertie, W. B. Ali, O. Raisky, D. Tamisier, D. Sidi, and P. R. Vouhe Aortic root replacement in children: a word of caution about valve-sparing procedures Eur. J. Cardiothorac. Surg., January 1, 2009; 35(1): 136 - 140. [Abstract] [Full Text] [PDF]
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 C. Tourmousoglou and C. Rokkas Is aortic valve-sparing operation or replacement with a composite graft the best option for aortic root and ascending aortic aneurysm? Interactive CardioVascular and Thoracic Surgery, January 1, 2009; 8(1): 134 - 147. [Abstract] [Full Text] [PDF]
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