Ann Thorac Surg 2003;75:1797-1801
© 2003 The Society of Thoracic Surgeons
Original article: cardiovascular
Fate of coronary ostial anastomoses after the modified Bentall procedure
Aldo D. Milano, MD, PhDa,
Stefano Pratali, MDa,
Gianclaudio Mecozzi, MDa,
Piero Boraschi, MDb,
Giovanni Braccini, MDb,
Enrico Magagnini, MDc,
Uberto Bortolotti, MDa*
a Division of Cardiac Surgery, Cardio-Thoracic Department, University of Pisa Medical School, Pisa, Italy
b Division of Radiology, Azienda Ospedalera Pisana, Pisa, Italy
c Division of Cardiology, Azienda Ospedalera Pisana, Pisa, Italy
Accepted for publication December 22, 2002.
* Address reprint requests to Dr Bortolotti, U.O. Cardiochirurgia, Ospedale Cisanello, Via Paradisa 2, 56124 Pisa, Italy.
e-mail: u.bortolotti{at}cardchir.med.unipi.it
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Abstract
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BACKGROUND: Introduction of the modified Bentall procedure with the button technique has reduced but not eliminated anastomotic complications in patients receiving a composite aortic conduit. Particularly the true incidence of coronary ostial complications such as stenosis, kinking or pseudoaneurysm formation needs to be assessed.
METHODS: We reviewed 71 patients receiving a composite aortic conduit from November 1993 to November 1999 for chronic aneurysms (n = 51) or aortic dissection (n = 20), 12 of whom had Marfan syndrome. Patients were divided into two groups according to variations in the surgical technique. In group 1 (30 patients; 42%) the classic modified Bentall operation with the button technique was employed whereas in group 2 (41 patients; 58%) some technical modifications were added mainly consisting of a reinforcement suture joining the cut edge of the aortic wall and the prosthetic sewing ring and suture of the coronary buttons with an "endo-button" technique. To detect potential procedure-related complications particularly at the coronary ostia anastomoses follow-up included transthoracic two-dimensional echocardiography every 6 months and computerized tomographic angiography at 12 months or whenever indicated; in 20 patients a magnetic resonance imaging angiography and standard aortography with selective coronary angiography were also added.
RESULTS: At a mean follow-up of 49 ± 19 months anastomotic complications occurred in 4 patients (6%): in 2 a pseudoaneurysm developed at the distal aortic suture line and in 1 a pseudoaneurysm developed at the right coronary ostium after repair of acute aortic dissection; in 1 Marfan patient an aneurysm of the left coronary ostium developed. Such complications were unrelated to the two surgical techniques used in this series for reimplantaion of the coronary ostia.
CONCLUSIONS: The modified Bentall operation is associated with an extremely low incidence of anastomotic complications particularly at the coronary ostia. More extensive use of new imaging techniques is desirable to assess the true incidence of such complications in patients receiving a composite aortic conduit.
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Introduction
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In 1968, Bentall and De Bono [1] described a technique to treat patients with aortic valve disease and aneurysm of the ascending aorta by means of a composite graft with direct side-to-side coronary reimplantation and graft wrapping by the residual aneurysmal wall. Although this operation has contributed considerably to improve the outcome of patients with aortic root disease, a high frequency of early and late postoperative complications mainly represented by pseudoanerysm formation at the coronary suture line has been reported [2–4]. For such reason, the classic Bentall operation has been currently replaced in most centers by an open modification with total resection of the aneurysm and reimplantation of adequately mobilized coronary buttons to the graft [5]. Despite technical modification complications after composite graft replacement of the ascending aorta have not been eliminated. Moreover, developments in new imaging techniques such as magnetic resonance imaging (MRI) angiography have recently resulted in increased detection of complications, particularly at the coronary ostial anastomoses [6, 7].
The present study was undertaken to assess the fate coronary ostial anastomoses after the modified Bentall procedure with the use of the button technique. The attention was focused on the incidence of coronary pseudoaneurysm formation, kinking of the coronary ostia, and ostial narrowing by comparing two different techniques for reimplantation of the coronary buttons.
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Material and methods
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Patient data
From November 1993 to November 1999, 71 patients were discharged after composite graft replacement of the aortic root. Patients were divided into two groups according to variations in the surgical technique as described below. Group 1 includes 30 patients (42%) operated on with the classic modified Bentall operation with the button technique; group 2 includes 41 patients (58%) operated on with the "endo-button" technique. Twenty patients (28%) underwent emergency operations for Stanford type A dissection whereas 51 (72%) had elective operations for chronic aneurysm of the ascending aorta. Diagnosis of Marfan syndrome was established in 12 patients (17%); no significant differences were found in the clinical characteristics summarized in Table 1.
Surgical technique
The technique proposed by Kouchoukos and coworkers [5] was employed in 30 patients (group 1), 19 with chronic aneurysm and 11 with acute dissection. The operation was performed under moderately hypothermic cardiopulmonary bypass with the use of a single dose of cold blood cardioplegia into the coronary ostia and continuous topical cooling. The ascending aorta was transected approximately 2 cm below the aortic clamp and removed; buttons of aortic wall including the coronary ostia were isolated and mobilized. The composite graft was inserted using multiple sutures of 2-0 Ethibond Excel (Ethicon,UK) reinforced by subannular Teflon felts. The aortic buttons containing the coronary ostia were anastomosed with a continuous suture of 4-0 Prolene (Ethicon) to openings in the vascular graft slightly larger than the diameter of the corresponding coronary ostium; foreign material to buttress coronary anastomoses was never used. The graft was then trimmed and sutured to the distal aorta with a continuous suture of 3-0 Prolene. In patients with acute dissection deep hypothermia with circulatory arrest was used to perform the distal anastomosis.
Recently some technical modifications have been added with the aim of minimizing postoperative bleeding. As described elsewhere [8] these included (1) a reinforcement suture joining the cut edge of the aortic wall and the prosthetic sewing ring [9] and (2) harvesting of the coronary ostia surrounded by a large portion of aortic wall, which allows the coronary buttons to be sutured in a two-layer fashion with a sort of "endo-button" buttress technique [10]. Such modifications were applied in 41 patients of this series (group 2), 25 with chronic aneurysm and 16 with dissection. In all patients fibrin glue was applied on sutures before release of the aortic cross clamp; in those with dissection the aortic layers were reconstructed with gelatin-resorcinol formaldehyde (GRF) glue applied only on the distal aorta. Mean aortic cross clamp time was 96 ± 32 minutes and mean duration of cardiopulmonary bypass 143 ± 47 minutes.
In 36 patients (25 of group 1 and 11 of group 2) a St. Jude Medical aortic valve graft (St. Jude Medical, St. Paul, MN) was used; in 35 patients (14 of group 1 and 21 of group 2) a Carbo-Seal composite graft (CarboMedics, Austin, TX) was used. Associated surgical procedures were performed in 9 patients (13%): coronary artery bypass grafting in 6 and mitral valve replacement in 3.
All patients were anticoagulated with subcutaneous calcium heparin starting from the first postoperative day; oral anticoagulants were administered upon discharge to the ward and were kept indefinitely with a target INR between 3 and 4.5.
Postoperative evaluation and follow-up
Patients were followed up at our outpatient clinic by direct evaluation and transthoracic two-dimensional echocardiographic studies every 6 months. As part of the postoperative follow-up protocol all patients of this series underwent computed tomographic (CT) angiography at 12 months follow-up or whenever indicated to monitor potential procedure-related complications. To more completely evaluate the status of coronary ostial anastomoses, after obtaining informed consent 20 patients, 8 of group 1 and 12 of group 2, agreed to undergo magnetic resonance imaging (MRI) angiography and standard aortography at the last follow-up visit. Selective coronary angiography was added with the aim of detecting kinking of the coronary anastomoses and narrowing of the ostia due to potential fibrous tissue growth at the coronary-graft interface.
Computed tomography angiography
The imaging data were obtained with a spiral CT (HiSpeed Advantage; GE Medical Systems, Milwaukee, WI) using the same acquisition protocol. The thoracic aorta was scanned in the cephalocaudal direction during a single breath hold from the aortic arch to the diaphragm. Acquisition time was 25 to 30 seconds. In all cases a volume of 150 mL of iohexol (iodine 300 mg/mL; Omnipaque 300; Nycomed Imaging, Oslo, Norway) was administered with a power injector. All axial images were reconstructed with 180-degree linear interpolation at 1-mm spacing by using a standard reconstruction algorithm.
Magnetic resonance imaging angiography
The MRI examinations were performed with a superconductive system operating at 0.5-T (Signa Contour, GE Medical Systems, Milwaukee, WI) with use of a body coil for both excitation and signal reception. The imaging protocol began with T1-weighted cardiac-gated, respiratory-triggered spin-echo sequences (TR, adapted automatically with the software according to the patient’s cardiac rhythm; TE, 14 msec; thickness, 6 mm; interslice gap, 1 mm; 2 signals averaged; FoV, 35 to 42 cm; matrix size, 256 x 192; acquisition time, 5 to 6 minutes) in the axial and oblique sagittal planes and T2-weighted cardiac-gated, fast, multiphase, gradient recalled echo sequences in the oblique sagittal plane. Contrast-enhanced MR angiography was performed using a breath-hold, three-dimensional, fast, spoiled gradient-echo sequence in the sagittal plane.
Statistical analysis
Data are presented as mean ± standard deviation. Comparison of the two groups of patients was performed using the 
2 test or Fisher test for discrete variables and the Student t test or Mann-Wilcoxon test as appropriate for continuous variables. All p values less than 0.5 were considered significant. The actuarial estimates of survival were determined using the Kaplan-Meier method.
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Results
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Late results
During the follow-up period completed in December 2001 (mean follow-up of 49 ± 19 months; range, 6 to 68) there were 5 late deaths. Two patients died in group 1 because of recurrent dissection after 7 months and chronic renal failure after 16 months respectively. In group 2, 3 patients died: 1 died of stroke after 6 months, 1 died suddenly after 15 months, and 1 died of congestive heart failure at 36 months. Actuarial survival at 5 years is 87% ± 4% in group 1 and 81% ± 6% in group 2 (Fig 1).
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Fig 1. Actuarial overall survival after composite graft replacement of the aortic valve and ascending aorta according to the different surgical technique used. Numbers on the horizontal axis indicate patients at risk. (Group 1 = circles; group 2 = triangles.)
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Aortic sequelae
Persistence of the false lumen in the distal aortic arch or descending aorta without evident dilation was detected at CT angiography in 10 patients with aortic dissection (6 in group 1 and 4 in group 2), which was confirmed by MRI angiography and aortography; in addition, extension of distal dissection was observed in 1 of them and 3 with signs of progressive dilation of the false lumen are currently being evaluated as potential candidates for endovascular stenting.
Anastomotic complications
A total of 4 (6%) anastomotic complications were detected in the late survivors, involving the distal aortic anastomosis in 2 and a coronary ostial anastomosis in 2. In 1 patient of group 1 pseudoaneurysm formation at the distal suture line was diagnosed at both CT and MRI angiography after operation for aortic dissection; this patient underwent successful reoperation after 13 months. In 1 patient of group 2 with aortic dissection a small pseudoaneurysm at the distal anastomosis was detected after 12 months at CT, MRI, and standard angiography. This patient is under close noninvasive monitoring. The contribution of GRF glue to the development of pseudoanerysm observed in these patients is difficult to establish but undoubtedly may arouse some concerns.
Coronary ostial complications were observed only in 2 patients. In a group 1 patient with aortic dissection, a pseudoaneurysm at the right coronary ostial anastomosis developed after 18 months and was detected both at MRI and angiography (Fig 2);
this patient has so far refused reoperation. In group 2 dilation of the left coronary anastomosis was observed at angiography after 23 months in a patient with annuloaoartic ectasia and Marfan syndrome (Fig 3).
In both cases a two-dimensional echocardiogram was not effective in reaching the correct diagnosis.
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Fig 2. Pseudoaneurysm at the right coronary ostial anastomosis (arrowhead) detected at magnetic resonance imaging angiography (upper panel) and confirmed at aortography (lower panel) in a patient 18 months after a modified Bentall procedure for aortic dissection. (PA = pseudoaneurysm; RCO = right coronary ostium; LCO = left coronary ostium.)
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Fig 3. Dilatation of the left coronary ostial anastomosis observed at aortography in a Marfan patient 23 months after operation for annuloaortic ectasia. (LCO = left coronary ostium.)
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On angiography no cases of coronary kinking were observed; in all patients evidence of perfectly patent coronary ostia with no signs of narrowing was demonstrated even at late follow-up regardless of the type of conduit employed.
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Comment
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Replacement of the ascending aorta and aortic valve with a composite conduit is a well-established method to treat patients with aortic valve disease and aneurysm of the aortic root [12, 13]. The classic Bentall wrap-inclusion method has been associated with pseudoaneurysm formation at the coronary anastomoses [2–4]; such a complication has been attributed to tension developing at the suture line of the side-to-side coronary anastomosis in large aneurysms or by blood accumulation inside the aortic wrap. For such reasons a modified open technique has been advocated that basically eliminates the prosthetic wrap and allows reattachment of adequately mobilized coronary buttons to the graft with tension-free sutures [5].
In performing composite conduit replacement of the ascending aorta we have always favored the open button technique [5]; however postoperative bleeding can still be a cause of major issue being difficult to control once insertion of the conduit is completed [9]. To minimize this problem we have recently adopted some technical modifications with the aim of enhancing hemostasis [8]. Among these, we consider it quite advantageous to suture the coronary ostia in a double layer fashion with an "endo-button" technique [10], which provides a large coaptation surface against the graft enhances hemostasis. This technique does not require the adjunct of suture reinforcement by foreign material and can be applied also in the fragile aortic wall as in cases of dissection. In our experience such technical modifications have proved effective in reducing postoperative bleeding and morbidity during replacement of the ascending aorta and aortic valve [8].
The present study was performed to evaluate the stability of the modified Bentall procedure over time and to verify whether the two different surgical techniques adopted for reattachment of the coronary ostia had any influence in the fate of coronary anastomoses. The occurrence of coronary ostia pseudoneurysms has been virtually eliminated by the open button technique; in fact no instances of reoperation for such complication have been reported in recent series [4, 13, 14]. The utility of new imaging techniques in evaluating patients undergoing composite graft replacement of the aortic root has been recently shown. Fattori and coworkers [6] have demonstrated that MRI is an optimal imaging modality to study the morphology of composite grafts and reimplanted coronary arteries and in detecting postoperative procedure-related complications. The importance of this technique in revealing late complications and allowing successful reoperation in such patients has been further emphasized by Mesana and colleagues [15]. We have observed only one case of coronary ostial pseudoaneurysm in a patient of group 1 after repair of acute aortic dissection with an incidence of 1.5% in our entire series. A similar experience has been reported by Dossche and coworkers [16] who identified 2 patients with pseudoaneurysm at the coronary ostial suture line even among those operated with the open technique; as in our case also, these patients had surgery for aortic dissection.
Coronary ostial aneurysms may also develop after composite graft replacement of the ascending aorta [17, 18]. Recently Meijboom and coworkers [7] have demonstrated that coronary ostial aneurysms are a common finding in patients with Marfan syndrome after elective aortic root surgery even when the button technique is used. In our series we observed 1 case of coronary ostial aneurysm in a Marfan patient of group 2, confirming that in such patients this complication is more likely related to the underlying disease than to the surgical technique employed. Finally it is interesting to underline that selective coronary angiography failed to disclose any case of coronary ostial narrowing due to potential scarring tissue at the ostial-graft interface confirming that direct coronary button reattachment is safe regardless the technique used.
The results of our investigation confirm the stability of the modified Bentall procedure over time. Medium-term results show an extremely low rate of coronary ostial complications, which therefore may be considered to be related more to technical errors or to fragility of the aortic wall in the individual patient than to the procedure itself. Owing to the limited data on patient surveillance by means of imaging techniques the true incidence of anastomotic complications after the modified Bentall procedure may be underestimated [19]. In our series MRI was more effective than two-dimensional echocardiography in detecting coronary anastomotic problems. Therefore more extensive use of such techniques, particularly MRI angiography, as currently advocated [6, 15] appears desirable as it might reveal a higher frequency of these complications even in patients operated on by the button technique.
This study has some obvious limitations. It is a retrospective study considering patients operated during approximately a decade. During this period techniques to treat patients with aortic valve disease and aneurysm of the ascending aorta have evolved. Indeed patients with annuloaortic ectasia are currently good candidates for aortic root remodeling procedures [20, 21] whereas for those with acute aortic dissection associated with aortic regurgitation root reconstruction with preservation of the native aortic valve appears to be the operation of choice [22]. For this reason comparison of group 1 and 2, owing to the negligible incidence of complications observed, did not show any statistically significant difference.
In conclusion our results confirm that the modified Bentall procedure is a valid option for patients who require simultaneous replacement of the aortic valve and ascending aorta with an extremely low incidence of complications particularly at the coronary ostial anastomoses at medium-term follow-up. Anastomotic pseudoaneurysms were observed only in patients with acute dissection and a coronary aneurysm was only identified in a Marfan patient, indicating that connective tissue disorders appear to play a significant role in development of these anastomotic problems. Therefore openings in the Dacron graft for implantation of the coronary arteries in Marfan patients should be kept relatively small to reduce the amount of aortic sinus tissue at the implant sites. Finally the influence of certain technical modifications in preventing anastomotic complications needs to be validated on longer follow-up and possibly in prospective randomized studies. [11]
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References
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Abstract
Introduction
