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Ann Thorac Surg 2002;74:S1765-S1768
© 2002 The Society of Thoracic Surgeons
a Department of Thoracic and Cardiovascular Surgery, Hannover Medical School, Hannover, Germany
* Address reprint requests to Dr Kallenbach, Hannover Medical School, Department of Thoracic and Cardiovascular Surgery, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany.
e-mail: kallenbach{at}thg.mh-hannover.de
Presented at the Aortic Surgery Symposium VIII, May 2–3, 2002, New York, NY.
Abstract
BACKGROUND: To assess the feasibility and outcome of the valve-sparing aortic root reimplantation technique in patients with severe preoperative aortic insufficiency (AI).
METHODS: Within 8 years we have operated on 158 patients with aneurysms of the ascending aorta using the reimplantation technique. We identified 83 patients with AI grade 3 or 4 (mean 3.1 ± 0.4) preoperatively (study group). This cohort was compared with 71 patients with AI grade 2 or less (mean 1.3 ± 0.9; control group) with regard to mortality, operative variables, complications, need for reoperation, postoperative AI, and clinical presentation during follow-up.
RESULTS: Patient demographics were comparable in both groups. However, Marfan’s syndrome (32% versus 13%, p = 0.006) and acute type A aortic dissection (20% versus 8.4%, p = 0.059) were more frequent in the control group. In addition, bypass (177 ± 60 minutes versus 160 ± 36 minutes, p = 0.022) and cross clamp times (133 ± 34 minutes versus 124 ± 27 minutes, p = 0.049) were significantly longer in controls. Mortality was low in the study group and comparable with controls (30-day, 3.6% versus 4.2%; during follow-up, 3.8% versus 5.9%; p = not significant [NS]). Reoperation rate was almost identical in both groups (3.8% versus 4.4%, p = NS). Mean grade of AI was significantly higher in the study group early postoperatively (0.31 ± 0.46 versus 0.18 ± 0.42, p = 0.049) but comparable at the last visit (0.43 ± 0.58 versus 0.42 ± 0.62, p = NS). During follow-up neither thromboembolic complications nor bleeding events were noted in either group. Clinical performance at the last visit revealed no significant difference between the groups.
CONCLUSIONS: Preoperative severe aortic insufficiency does not impair the excellent outcome seen after a mean of 3 years of follow-up in patients undergoing the reimplantation technique for valve-sparing aortic root reconstruction.
Ectasia of the aortic root or ascending aortic aneurysm may cause aortic valve insufficiency by dilation of the sinotubular junction or aortic annulus or both [1]. If the aortic cusps are of normal structure, an aortic valve-sparing operation for replacement of the aortic root and ascending aorta is feasible. Various techniques have been developed for valve-sparing aortic root reconstruction [2, 3] and this treatment strategy has recently gained wide acceptance with excellent midterm results with regard to mortality, morbidity and the durability of the reconstructed aortic valve [4–6]. However, use of the reimplantation technique in patients with severe aortic insufficiency remains controversial. To address this problem we analyzed outcome in 154 patients who underwent aortic valve reimplantation but differed with regard to the severity of their preoperative aortic insufficiency.
Patients and methods
Patients
Between July 1993 and July 2001, we performed 2,257 operations involving the aortic valve. The valve was replaced in 2,099 patients with 566 biological prostheses, 1,091 mechanical valves, 48 homografts, and 359 aortic valved conduits (14.5%). One hundred fifty-eight patients (7%) underwent operations for aneurysms of the ascending aorta using the reimplantation technique for aortic valve reconstruction according to David and Feindel [3]. The majority of patients (n = 154) underwent preoperative echocardiography for assessment of aortic valve function and cusp structure. Among these 154 patients we identified 83 patients with aortic insufficiency (AI) grade 3 or more preoperatively (study group). This cohort was compared with 71 patients with preoperative AI grade 2 or less (control group) with regard to mortality, operative variables, complications, need for reoperation, postoperative AI and clinical presentation during follow-up. Patient demographics of both groups are shown in Table 1.
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Surgical technique
The operative technique used for this procedure was recently described by our group [5]. In brief, a standard median sternotomy and extracorporeal circulation as well as standard myocardial protection techniques were used in all patients. After assessing suitability for valve reconstruction, excision of the coronary ostia and resection of aortic sinuses up to a rim of 2 to 3 mm of aortic wall as well as extensive external dissection and mobilization of the aortic root were carried out. Prostheses 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 dilator and the diameter of the sinotubular junction with a valve sizer (St. Jude Medical, St. Paul, MN). Valve coaptation was considered ideal if 30% to 50% of the cusp area was involved after correcting the diameter of the sinotubular junction.
Proximal anastomosis was performed with approximately 12 threads of 3-0 coated polyester fiber (Ethibond; Ethicon, Hamburg, Germany) used as a horizontal mattress suture placed circumferentially through the annulus underneath the valve. Sinuses were reimplanted into the Dacron prosthesis using three 4-0 polypropylene sutures (Prolene; Ethicon). Utmost care was taken to achieve correct cusp geometry and sufficient height of commissural resuspension within the prosthesis. Reimplantation of coronary ostial buttons completed the aortic root reconstruction. In cases with acute type A dissection of the aorta or large aneurysms involving the aortic arch, deep hypothermic circulatory arrest and more recently moderate hypothermic circulatory arrest with cold (15°C) antegrade cerebral perfusion were utilized.
Follow-up
Mean follow-up for the study group was 39 ± 27 months, with a minimum of 2 months and a maximum of 96 months. In control patients, mean follow-up was 33 ± 22 months (1 to 9 months). Patients undergoing root reconstruction received either acetylsalicylic acid or coumadin for 3 months postoperatively.
Routine intraoperative or immediate postoperative assessment of aortic valve function was carried out using transesophageal echocardiography. Valve function was reevaluated using transthoracic color Doppler echocardiography before hospital discharge and at 1 to 2 year intervals thereafter. Valve morphology as well as systolic and diastolic function were assessed in accordance with published criteria [7]. Aortic regurgitation was assessed semiquantitatively as follows: 0, none; I, minimal; II, mild; III, moderate; or IV, severe. Valve performance, complications, and outcome analysis are reported as suggested by the guidelines of the American Association for Thoracic Surgery/Society of Thoracic Surgeons [8].
Statistical analysis
Continuous variables are expressed as mean ± SD. All data analyses were performed with SPSS 10.0.7 for Windows (SPSS, Chicago, IL). Kaplan-Meier analysis was used for the evaluation of time-related variables. The Mann-Whitney test was utilized for variables which were not normally distributed. Statistical comparison between the groups for the influence of acute type A aortic dissection, Marfan’s syndrome, rethoracotomy, and aortic cusp augmentation was performed by using Fisher’s exact test for the analysis of contingency tables. A value of p less than 0.05 was considered significant.
Results
Perioperative outcome
The aortic valve was successfully preserved in all 154 patients. In the study group, early (30-day) mortality was 3.6% (3 patients). In the control group, early mortality was 4.2% (3 patients, p = NS). The 3 patients in the control group died of peripheral complications after emergency operations owing to acute type A aortic dissection. In the study group, patients died of non–valve-related complications after elective surgery for complex cardiac and aortic pathologies.
Mean circulatory arrest times (29 ± 20 minutes, range 9 to 99, versus 23 ± 13 minutes, range 7 to 50; p = NS) were comparable in both groups, while mean bypass time (177 ± 60 minutes, range 107 to 440, versus 159 ± 36 minutes, range 99 to 285; p = 0.022) and mean aortic cross clamp time (133 ± 34 minutes, range 87 to 202, versus 124 ± 27 minutes, range 79 to 203; p = 0.049) were significantly longer in the control group. Patients presenting with acute type A aortic dissection were more frequent in the control group (14 versus 7 patients, p = 0.059). The number of additional surgical procedures was comparable between the groups in terms of arch replacement, aortocoronary bypass grafting and elephant trunk extension into the descending aorta. Additional mitral valve surgery was required in 7 Marfan patients with cusp prolapse, all in the control group. Free margin shortening of aortic cusps (Trusler plasty) was performed in 12 patients (14%) presenting with significant AI preoperatively, in contrast to only 3 patients (4.2%) in the control group (p = 0.054). Two patients (2.4%) in the study group and 5 (7%) in the control group required rethoracotomy due to bleeding (p = NS). Length of stay in the intensive care unit ([ICU] 1.8 ± 1.3 days, range 1 to 7, versus 2.7 ± 3.6 days, range 1 to 25) and duration of hospitalization (15 ± 8 days, range 8 to 46, versus 15 ± 10 days, range 9 to 76) were comparable between study and control groups.
Follow-up
In the study group with significant preoperative AI, 3 patients (3.8%) died during follow-up. In the control group, mortality was comparable (4 patients; 5.9%; p = NS). Cardiac-related mortality was 3.8% (3 patients) for the study group and 2.9% (2 patients) for the control group. Actuarial survival at 1, 3, and 5 years was 98.7 ± 1, 96.9 ± 2, and 96.9 ± 2 versus 96.7 ± 2, 96.7 ± 2, and 96.7 ± 2, respectively (p = NS).
Reoperation for aortic valve morbidity was required in 3 patients (3.8%) in the study group and in 3 control patients (4.4%), demonstrating no statistically significant difference between the groups. Actuarial freedom from reoperation is shown in Figure 1A. In the study group reasons for reoperation were endocarditis, cusp degeneration due to Wegener’s granulomatosus, and primary valve failure due to inadequate technique of valve suspension. In the control group, endocarditis and inadequate technique in two cases initiated reoperation. In the study group, the mean grade of aortic insufficiency was 0.31 ± 0.46 with a minimum of 0 and a maximum of 1 early postoperatively. This value was significantly higher than in patients in the control group (0.18 ± 0.42, 0 to 2; p = 0.049). At the last visit, however, the mean grade of aortic insufficiency increased slightly in both groups compared with early postoperatively: the difference between the groups lost statistical significance (0.43 ± 0.58, 0 to 2 for the study group compared with 0.42 ± 0.65, 0 to 3 for the control group). Actuarial freedom from clinically relevant severe aortic insufficiency grade more than 2 is plotted in Figure 1B for both groups, revealing no significant difference.
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Comment
This study analyzed the influence of preoperative severe aortic insufficiency on outcome in patients undergoing the reimplantation technique for valve-sparing aortic root reconstruction. We conclude that the severity of preoperative aortic insufficiency has no influence on survival or need for reoperation for postoperative aortic valve failure. Although the grade of aortic insufficiency early postoperatively was significantly higher for patients in the study group than in those with mild AI preoperatively, the clinical meaning of this finding is questionable as the average grade of AI was below grade 1 in both groups. Furthermore, the mean grade of AI revealed no statistically significant difference between the groups at their last visit after more than 30 months’ mean follow-up. The increased number of additional reconstructive techniques at the aortic cusps to avoid cusp prolapse did not adversely affect valvular stability in the study group.
Just recently our group has demonstrated the feasibility of aortic valve reconstruction in aneurysms of the ascending aorta with excellent midterm results [9], thereby confirming the findings of others [4, 6]. Regardless of the surgical technique, excellent results were achieved with valve-sparing techniques in Marfan patients [10, 11] despite preoperative moderate to severe AI in more than half of them. These results contrast with the findings of Fleischer and colleagues [12], who demonstrated fibrillin fragmentation and deficiency in the aortic cusps in patients older than 60 years and in patients with Marfan’s syndrome and who therefore suggest careful reexamination of the rationale for valve-sparing repair of aortic root aneurysms in these patients. Although there may be debate in Marfan patients with severe aortic insufficiency about the use of valve-sparing operations because of their potential for long-term progression of the disease, scientific evidence for a worse outcome for those patients after aortic valve-preserving surgery is missing to date. In contrast, the findings of this study—the excellent functional outcome of valve-sparing techniques in Marfan patients combined with the advantage of avoiding long-term anticoagulation—suggest that the reimplantation technique may result in a superior clinical outcome than with composite replacement of the aortic valve and ascending aorta [13].
We therefore conclude that valve-sparing aortic root reconstruction techniques can be used in patients presenting with severe aortic insufficiency without an increased risk of valve-related postoperative complications.
References
This article has been cited by other articles:
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  K. Kallenbach, R.G. Leyh, R. Salcher, M. Karck, C. Hagl, and A. Haverich Acute aortic dissection versus aortic root aneurysm: comparison of indications for valve sparing aortic root reconstruction Eur. J. Cardiothorac. Surg., May 1, 2004; 25(5): 663 - 670. [Abstract] [Full Text] [PDF]
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T. Carrel, L. Beyeler, A. Schnyder, P. Zurmuhle, P. Berdat, J. Schmidli, and F. S. Eckstein Reoperations and late adverse outcome in Marfan patients following cardiovascular surgery Eur. J. Cardiothorac. Surg., May 1, 2004; 25(5): 671 - 675. [Abstract] [Full Text] [PDF]
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 M. Karck, K. Kallenbach, C. Hagl, C. Rhein, R. Leyh, and A. Haverich Aortic root surgery in Marfan syndrome: Comparison of aortic valve-sparing reimplantation versus composite grafting J. Thorac. Cardiovasc. Surg., February 1, 2004; 127(2): 391 - 398. [Abstract] [Full Text] [PDF]
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 C. Hagl, J. T. Strauch, D. Spielvogel, J. D. Galla, S. L. Lansman, R. Squitieri, C. A. Bodian, and R. B. Griepp Is the bentall procedure for ascending aorta or aortic valve replacement the best approach for long-term event-free survival? Ann. Thorac. Surg., September 1, 2003; 76(3): 698 - 703. [Abstract] [Full Text] [PDF]
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