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Eur J Cardiothorac Surg 2004;25:663-670
© 2004 Elsevier Science NL
Department of Thoracic and Cardiovascular Surgery, Hannover Medical School, Hannover, Germany
Received 20 October 2003; received in revised form 12 January 2004; accepted 14 January 2004.
* Corresponding author. Address: Medizinische Hochschule Hannover, Klinik für Thorax-, Herz- und Gefäßchirurgie, Carl-Neuberg-Straße 1, D-30625 Hannover, Germany. Tel.: +49-511-532-2253; fax: +49-511-532-5404
e-mail: kallenbach{at}thg.mh-hannover.de
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Abstract |
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 Top Abstract 1. Introduction2. Methods and patients3. Results4. DiscussionAppendix A. Conference...References |
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Key Words: Aortic aneurysm • Aortic dissection • Valves • Aorta • Valve reconstruction
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1. Introduction |
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TopAbstract1. Introduction2. Methods and patients3. Results4. DiscussionAppendix A. Conference...References |
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2. Methods and patients |
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TopAbstract1. Introduction2. Methods and patients3. Results4. DiscussionAppendix A. Conference...References |
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For patients from root, our standard indications for aortic valve reimplantation have been aneurysms of the ascending aorta or aortic root larger than 5–6 cm in diameter, a tricuspid aortic valve without gross structural defect, and absence of severe cusp prolapse or asymmetry. Recently, we liberalized our indications for valve preservation towards bicuspid valves and also smaller root diameters (>4 cm) in Marfan patients with a family history of acute aortic dissection. Coronary angiography, aortic root angiograms, transthoracic echocardiography, and computed tomography scans or magnetic resonance images were performed routinely in elective cases. If pre-operative echocardiograhic evaluation by a cardiologist found the aortic cusps unimpaired, reconstruction had been considered. As for patients from AADA, the final decision to preserve the aortic valve was made by the surgeon after inspection of valve cusps and root geometry.
2.2. Surgical technique
The operative techniques used for this procedure were recently described by our group [6,10]. In patients presenting with AADA, the anaesthesiologist placed arterial lines in both radial arteries and one femoral artery for detection of peripheral malperfusion during the procedure. During preparation for the procedure, one leg was also surgically prepped and draped in all patients for vein graft harvest if required. Prior to median sternotomy and pericardioectomy, the left femoral artery was dissected for arterial cannulation in unstable patients with pericardial effusion. In stable situation, cannulation of the ascending aorta and the right atrium for extracorporeal circulation was undertaken. Cooling to a rectal temperature of 28–30 °C was initiated and myocardial protection was conducted with repetitive doses of cold blood cardioplegia in an antegrade fashion after aortic cross clamping and transsection of the ascending aorta above the commissures. After careful inspection, the decision for reconstruction of the aortic valve depended on the morphological appearance of the cusps and root geometry. In case of dissection of the root involving the commissures, the wall layers were readapted with GRF-glue.
After assessing the suitability of valve reconstruction, excision of the coronary ostia and resection of aortic sinuses up to a remnant of 2–3 mm, as well as extensive external dissection and mobilization of the aortic root, followed. Prosthetic diameters were calculated from the diameter of the left ventricular outflow tract and the height of the aortic cusps. Practically, the annulus was sized with a Hegar dilatator and the sinotubular junction with a valve sizer (St Jude Medical®, St Paul, MN, USA). Valve coaptation was considered ideal if 30–50% of the cusp area was involved after modification of the sinotubular junction. Proximal anastomosis was performed with 12 threads of 3–0 coated polyester fibre (Ethibond®, Ethicon Inc., Hamburg, Germany) used as a horizontal mattress suture placed circumferentially through the annulus underneath the valve. The valve cuff was then reimplanted into the Dacron prosthesis using three 4–0 polypropylene sutures (Prolene®, Ethicon Inc.). Utmost care was taken to achieve correct cusp geometry and sufficient height of commissural resuspension within the prosthesis. If necessary, dissected coronary artery ostia were reconstructed using GRF-glue. Reimplantation of coronary ostia button into the Dacron graft completed the root reconstruction. In cases with acute type A dissection of the aorta or large aneurysm involving the aortic arch, deep hypothermic circulatory arrest or, more recently, moderate hypothermic circulatory arrest with cold (15 °C) antegrade cerebral perfusion was utilized. Depending on the expansion of the dissection, the diseased aortic wall was either reconstructed with GRF-glue or removed and the arch replaced by a second Dacron prosthesis. In case of more extensive distal dissection or aortic aneurysms, an elephant trunk extension of the arch prosthesis into the proximal descending aorta was used.
2.3. Follow-up
Before hospital discharge and at follow-up, valve function was re-evaluated using transthoracic colour Doppler echocardiography. Valve morphology as well as systolic and diastolic functions was assessed in accordance with published criteria [11]. Aortic regurgitation was assessed semiquantitatively as follows: 0, none; I, minimal; II, mild; III, moderate; IV, severe. Infectious, thromboembolic, and bleeding complications were recorded as required by the guidelines of the American Association for Thoracic Surgery/Society of Thoracic Surgeons [12].
After aortic valve reconstruction, patients were anticoagulated with coumandin or aspirin (at the discretion of the individual surgeon) to prevent thromboembolic complications for 3 months. Thereafter, anticoagulation therapy was discontinued.
Patient's performance was assessed either directly or in a telephone-interview in regard to the classification of the New York Heart Association (NYHA).
2.4. Statistical analysis
Continuous variables are expressed as mean±SD. All data analyses were performed with SPSS 11.0 for Windows (SPSS Inc., Chicago, IL, USA). Demographic and baseline variables were analysed using Student's t-test for continuous variables. Comparison between groups was performed using 
2 test for the analysis of contingency-tables. Kaplan–Meier analysis was used for the evaluation of time-related variables. Differences between survival curves were evaluated with log-rank statistic. Statistical significance of differences in aortic insufficiency and NYHA-class between groups was tested using Mann–Whitney signed rank test for normally distributed data. A value of P<0.05 was considered significant.
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3. Results |
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TopAbstract1. Introduction2. Methods and patients3. Results4. DiscussionAppendix A. Conference...References |
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Operation times were significantly longer for AADA. However, additional procedures such as arch replacement and elephant trunk extension into the descending aorta were performed more often in AADA. Operation times and additional surgical procedures are listed in Table 2.
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3.2. Post-operative follow-up
Although patients were matched by the time point of operation, follow-up was longer for patients from root with 29±20 (1–97) vs. 19±21 (1–90) months for patients from AADA due to earlier termination of follow-up by death or reoperation. During follow-up, four patients from AADA died, but none from root. All four patients died during the first post-operative year, and none of the death was related to the reconstructed valve. Latest echocardiography showed sufficient reconstructed valves for all four patients. One female patient was paraplegic post-operatively and died on post-op day 40 in a neurological rehabilitation centre for unknown reasons. Another patient was discharged post-operatively to a peripheral hospital. She recovered well and died for unclear reasons during rehabilitation on post-op day 48. After an uneventful post-operative course after valve reconstruction, arch replacement and extension of an elephant trunk into the descending aorta, one gentleman died on post-op day 46 for rupture of the descending aorta. Another patient died 10 months post-operatively due to onset of ventricular fibrillation. Actuarial survival was 100% for root after 3 and 5 years, and 88±5% for AADA at 3 and 5 years. This difference was found to be significant (log rank, P=0.026). Actuarial survival for both groups is shown in Fig. 1
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Freedom from reoperation due to aortic valve morbidity was 97±3% after 3 and 5 years for root and 97±3% after 3 years and 65±26% after 5 years for AADA. This difference was statistically not significant (log rank, P=0.46). Actuarial freedom from reoperation is given in Fig. 2 .
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During follow-up, no bleeding complication have been reported. In root, two (5%) thromboembolic events were documented and one (3%) in AADA. Both patients from root suffered from a transient ischemic attack but recovered completely. There was no significant difference between groups (P=0.71).
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4. Discussion |
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TopAbstract1. Introduction2. Methods and patients3. Results4. DiscussionAppendix A. Conference...References |
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The indication for the reimplantation technique in elective patients presenting with aneurysms of the ascending aorta or the aortic root is widely accepted: aneurysms larger than 5–6 cm and a morphological intact valve without severe cusp prolapse or asymmetry. Recently, in selected cases bicuspid valves and root diameter larger 4 cm in high risk patient such as Marfan's syndrome with the family history of dissection were operated with this technique, too [2,3]. We have recently reported that neither the severity of pre-operative aortic insufficiency nor the size of the aneurysm influences the durability of the reconstructed valve [13,14]. We and others have shown that the use of reimplantation technique in patients with Marfan's syndrome is safe in regard to valvular longevity, but bear the advantage of avoidance of lifelong anticoagulation, of which specifically these patients with younger age, potentially necessary later operation of the downstream aorta and possible gravidity will benefit [15,16]. The indication for use of the reimplantation technique in emergency patients presenting with acute aortic dissection remains debatable. Should such a demanding, time-consuming technique be used in an emergency situation, most often in the middle of the night? Or should the most simple and quickest technique be applied, such as the supracommissural aortic replacement or the composite replacement? Unquestionably, reconstruction of the aortic root with GFR-glue and supracommissural replacement of the ascending aorta represents probably the easiest and quickest approach, but leaves diseased aortic tissue in place ignoring the underlying aortic wall pathology. Possible redissection or aneurysm formation may bear a vital risk for the patient and may require further operation of the proximal ascending aorta. Although the mechanism of the development of secondary aneurysmatic dilatation of the aortic root after supracommissural replacement remains unclear and may be multifactorial, these aneurysms are the main reasons for reoperations due to the development of moderate to severe aortic regurgitation with an incidence of 25–45% [17,18]. In patients with structurally impaired aortic wall tissue such as Marfan's syndrome and in those who had acute dissection with pre-existing annuloaortic ectasia on the basis of cystic medial necrosis, the incidence may be even higher and composite replacement has been recommended. The replacement of the aortic wall and the dissected ascending aorta with a composite graft carrying mechanical valve prosthesis represents an established surgical treatment with excellent results [19,20]. However, the lifelong need for anticoagulation with the risk for bleeding and possible thromboembolic events after mechanical valve replacement cause complications with an annual incidence of 2–4% in the literature [21]. These complications can be avoided by the use of the valve preserving reimplantation technique. In a recent study, we reported on a matched pair analysis of patients with ascending aortic aneurysm treated either with composite replacement or the valve sparing reimplantation technique. We observed no bleeding or thromboembolic complications in the latter group; there were significantly more events in the first post-operative year after composite replacement [22]. In addition, absence of anticoagulation is particularly appealing in patients requiring additional surgery due to aneurysmatic transformation of dissected distal aortic segments. Nevertheless, we had two patients from root who developed a transitoric ischemic attack with complete recovery during follow-up. Due to the reduced number of patients in the cohort, the incidence of 5% appears to be high. However, of more than 200 patients operated with the reimplantation method for root aneurysm, we are aware of only these two neurological complications, and the high incidence in this matched paired cohort seems to be randomly high. To avoid early post-operative neurological complications by thromboembolism, most of our surgeons prefer anticoagulation with coumandin for 2 months until complete endothelialization of suture lines have completed.
We report of 3 out of 44 patients (6.8%) of both groups who needed a re-thoracotomy due to post-operative bleeding. This incidence is in agreement with earlier reports by us and others, varying between 4.4 and 6% for reexploration, thus demonstrating excellent hemostatic features of the reimplantation method [2,3]. Besides reimplantation technique, aortic root remodelling, first described by Yacoub et al. [23], is an alternative with excellent results. However, de Oliveira et al. reported of a re-thoracotomy rate of 3% for Marfan patients undergoing the reimplantation operation vs. 18% in the remodelling group. This difference was found to be statistically significant (P=0.01). Miller stated in a most recent review of valve sparing aortic root replacement in patients with Marfan's syndrome, that the reimplantation concept is better for acute aortic dissection since it is more hemostatic—the only suture lines that can bleed are the coronary buttons and the distal aortic anastomosis [24].
With no peri-operative mortality and an actuarial survival of 100% at 5 years, the outcome of elective patients operated for aortic root aneurysms is excellent. Similar results were archived by David et al. [3], who reported on one peri-operative death out of 64 patients (1.6%) treated with the reimplantation technique. Our group [2] reported on a peri-operative mortality of 2.2% in 136 elective cases. However, in this study, five patients from AADA (11.4%) died peri-operatively. Another four patients died during the first year after operation, one of them for peri-operative cerebral infarction still in hospital, and two others during rehabilitation. Actuarial survival was 88±5% at 5 years. In comparison to the literature, reporting a peri-operative mortality for surgical repair of AADA of 25% [25], these data represent acceptable results. It is important to stress that reconstruction of the aortic valve did not cause any death in a direct pattern. The majority of deaths were related to cerebral and peripheral malperfusion due to the aortic dissection. At the time point of presentation for surgery at our institution, 25% of patients from AADA were in cardiogenic shock, 23% showed symptoms of cerebral or/and peripheral malperfusion.
Freedom of reoperation for aortic valve morbidity was 97±3% at 3 years for both indications. One patient from AADA, who suffered from acute dissection of the donor aorta 2 weeks after initial heart transplantation, had to be reoperated after 5 years due to fibrotic endocarditis. The grade of aortic insufficiency at last visit did not differ between groups. By use of a matched pair analysis, which allows comparison of individual cases and resulted in relatively homogenic groups for comparison, neither the need for reoperation nor the grade of aortic insufficiency is influenced by the indication for operation. Furthermore, clinical performance during follow-up is comparable. These findings are in agreement with reports of others, who demonstrated excellent valvular stability in patients who received the valve sparing reimplantation technique for treatment of AADA [8,9]. Due to the lack of sinuses of Valsalva, progressive leaflet degeneration has been discussed as a theoretically possible drawback of the method. However, neither echocardiographic findings nor increased valve failure after prolonged follow-up support this hypothesis. Longer follow-up is required to finally judge the valvular stability after reimplantation.
The demanding aspect of the surgical technique might represent a limitation of our strategy to operate AADA with the reimplantation technique. Thus, the surgeon on duty must be well trained in elective cases to feel confident using this technique under emergency conditions.
Rare bleeding complications early post-operatively, freedom from anticoagulation as well as complete resection of diseased tissue is particularly appealing and represent unquestionable advantages to established methods. In our centre, the described reimplantation operation advanced to the procedure of choice in patients suffering from AADA with intact valve cusps and/or aortic tissue defects. Further long-term studies must prove whether these benefits will outweigh the potential risk for reoperation.
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Footnotes |
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Appendix A. Conference discussion |
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TopAbstract1. Introduction2. Methods and patients3. Results4. DiscussionAppendix A. Conference...References |
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And how would you proceed? Because bicuspid valve might be associated with a higher risk of dissection in some patients at least.
Dr Kallenbach: No, we didn't have any of this. Our goal is to use this operation in any patient, but we do not do it in all patients. If there is a bicuspid valve in this emergent situation, the surgeon might be able to accomplish a replacement.
Dr J. Bachet (Paris, France): If I remember well, a few years ago your group published a paper about, I think, 22 patients with acute dissection having a valve-sparing procedure. And the conclusions were quite negative. You were disappointed by this technique. But most patients had a remodeling procedure.
In this presentation, all patients had a reimplantation procedure. Do you think that the difference in the result is not due to the fact that we deal with dissections but that the remodeling procedure is less appropriate than the reimplantation technique?
Dr Kallenbach: All those 22 patients were operated with the reimplantation technique. We compared them to eight patients treated with the remodeling technique.
In '93, when we started with aortic reconstruction, we did five remodeling operations at Hannover and few more at Lübeck by Dr Leyh. After that, we only used reimplantation technique as published by Tirone David. Our first results published in the European Journal of Cardio-thoracic Surgery with 22 patients were very good with low reoperation rate so far and an early mortality of about 14%. We prefer the reimplantation since the remodeling technique showed more often failure in patients with acute aortic dissection.
Dr Carrel: I would ask a question about the severity of the fragmentation of fibrillin in Marfan patients. I had the privilege some years ago to see some immunohistology from the study of Vincent Gott, and I was surprised by the different degrees of the severity of the disease within excised cusp. Do you think there is a potential correlation about clinical presentation of the Marfan, or of the disease, with the involvement of fibrillin fragmentation in the cusp which could predict a bad result when this fragmentation is very high?
Dr Kallenbach: Well, the fibrillin problem is an ongoing discussion in this field. And I don't think that you can judge from the presentation of the patient to the valve. What we can do is judge the valve before the operation by echo and look at the valve intraoperatively: What is the impression of the surgeon? And then he has to decide: Do I believe I can reconstruct this valve with a good long-term result, or not?
Looking in the literature, just recently Tirone David reported, I believe, 80 patients with Marfan syndrome who were operated with reimplantation with excellent results, even better than in the patients who had no Marfan syndrome. And we recently gave a paper at the AATS, which will be published soon, where we also compared Marfan syndrome patients with the David reimplantation technique and the Composite technique. And we also found very good result of long-term durability.
But really hard data, how to judge this, unfortunately, I don't have that.
Dr Carrel: Would you repair mitral moderate regurgitation if you have a prolapse in an acute dissection?
Dr Kallenbach: Actually, we had two patients who got mitral valve repair. They were elective cases. We would probably repair a prolapse in a Marfan patient with acute aortic dissection if he presents in fairly stable condition without significant malperfusion.
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References |
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TopAbstract1. Introduction2. Methods and patients3. Results4. DiscussionAppendix A. Conference...References |
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