Ann Thorac Surg 2003;75:1792-1796
© 2003 The Society of Thoracic Surgeons
Original article: cardiovascular
Total arch replacement for thoracic aortic aneurysm via median sternotomy with or without left anterolateral thoracotomy
Toshihiro Ohata, MDa*,
Tetsuo Sakakibara, MDa,
Hiroshi Takano, MDa,
Toru Ishizaka, MDa
a Division of Cardiovascular Surgery, Osaka Police Hospital, Osaka, Japan
Accepted for publication December 12, 2002.
* Address reprint requests to Dr Ohata, Department of Cardiovascular Surgery, Osaka Prefectural General Hospital, 3-1-56 Bandai-Higashi, Sumiyoshi-ku, Osaka, 558-8558, Japan
e-mail: tohata{at}aol.com
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Abstract
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BACKGROUND: Thoracic aneurysms involving the ascending aorta, arch, and descending aorta are usually approached in a series of operations. Here, we report our clinical experience with total arch replacement through a median sternotomy with or without left anterolateral thoracotomy, using a technique that preserves the anterior wall of the distal arch to avoid injuring the left recurrent and phrenic nerves.
METHODS: Between March 1999 and February 2001, 32 consecutive patients underwent total arch replacement through a median sternotomy alone (median group, n = 23) or in combination with a left anterolateral thoracotomy (LAT group, n = 9). In all cases, antegrade hypothermic selective cerebral perfusion was used in conjunction with mild hypothermic visceral perfusion (cool head–warm body perfusion).
RESULTS: There were no in-hospital deaths and two late deaths. One patient in the median group had permanent neurological dysfunction postoperatively. There were no significant differences between the two groups in bypass time, cardiac ischemic time, respiratory assist time, beginning peroral intake, hospital stay, or postoperative respiratory function. The distal anastomosis level was significantly lower in the LAT group (thoracic vertebra level 7.1 ± 1.5 vs 5.6 ± 0.5, p = 0.0015).
CONCLUSIONS: Preservation of the anterior wall in the distal arch may decrease in-hospital mortality and perioperative neurological dysfunction after total arch replacement. Total arch replacement through a median sternotomy with left anterolateral thoracotomy allowed expeditious and extended replacement of the aorta without increasing postoperative respiratory complications.
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Introduction
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Despite advances in surgical procedures, management of anesthesia, and cardiopulmonary bypass technique [1–3], brain injury after thoracic aorta operations remains an important source of morbidity and mortality because of the advanced age of the patients and the presence of severe comorbidities [4, 5]. Thoracic aneurysm involving the ascending aorta, arch, and descending aorta is usually approached in staged operations [6–8]. However, single-stage replacement of the aortic arch and descending aorta may be the preferable surgical option for a certain situation of atherosclerotic aneurysm, chronic type A or type B dissection.
We have reported the clinical usefulness of total arch replacement in which the anterior wall of the distal aortic arch is preserved to avoid injuring the left recurrent and phrenic nerves [9]. However, the preserved wall occasionally makes it very difficult to perform the distal anastomosis. To circumvent this difficulty, we refined our procedure by performing a left anterolateral thoracotomy in addition to the median sternotomy. Here, we report our initial clinical experience with 32 cases of total arch replacement for thoracic aortic aneurysm.
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Patients and methods
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Patients
Between March 1999 and February 2001, 32 consecutive patients with thoracic aortic aneurysm underwent total arch replacement at Osaka Police Hospital. There were 23 men and 9 women, with a mean age of 68 ± 9 years (range, 44 to 79 years). The operation was performed through a median sternotomy in 23 patients (median group) and through a median sternotomy plus a left anterolateral thoracotomy in 9 patients (LAT group). In the median group, 16 patients had a distal arch aneurysm and 7 had an arch aneurysm. In the LAT group, 5 had a distal arch aneurysm, 2 had chronic type B dissection, 1 had a ruptured aneurysm of descending aorta, and 1 had chronic type A dissection after a graft replacement of ascending aorta. The patient with a ruptured aneurysm of the descending aorta underwent an emergent operation (Table 1). In the LAT group, 1 patient had previously undergone graft replacement of ascending aorta, and 1 had undergone stent graft implantation for a pseudoaneurysm after graft replacement of the distal arch. Two patients in the LAT group underwent concomitant cardiac procedures, coronary artery bypass grafting in 1 and Bentall’s operation in 1.
Operative technique
In all patients, the right radial artery and the left femoral arterial pressure were monitored, and a Swan-Ganz catheter was placed in right jugular vein to monitor pulmonary and central venous pressure. The jugular venous oxygen saturation was continuously monitored with a 4-F fiber optic oxymeter catheter (Opticath; Abbot Laboratories, North Chicago, IL). Both the nasopharyngeal and the bladder temperature were monitored throughout the operation.
In the median group, the patient was put under general anesthesia, the left axillary and right femoral arteries were exposed, and the heart, ascending aorta, aortic arch, and arch vessels were exposed through median sternotomy. The innominate vein was ligated and divided, and epiaortic echography was performed to identify the least atherosclerotic site in the bracheocephalic and left common carotid arteries for selective cerebral perfusion before establishment of cardiopulmonary bypass. After systemic heparinization, an 8-mm-diameter graft was anastomosed to the left axillary artery for systemic arterial cannulation. Cardiopulmonary bypass was instituted, with the arterial cannula placed in the axillary 8-mm graft and a single two-stage cannula placed for venous drainage in the right atrium. Myocardial protection was obtained by intermittent antegrade and retrograde cold-blood cardioplegia. When the patient’s nasopharyngeal temperature reached 25°C, systemic circulation was arrested, and the aorta was opened. Both the bracheocephalic and the left common carotid artery were completely transected at the intact portion, and then a 14- or 12-F balloon-tipped perfusion cannula was inserted into them with great care (Fig 1).
A 12-F balloon-tipped cannula was inserted into the 8-mm graft to perfuse of left vertebral artery. The temperature of antegrade selective cerebral perfusion was maintained at 25°C, and the cerebral perfusion flow through each vessel is adjusted to maintain the mean carotid arterial pressure at 40 to 50 mm Hg [9].
After selective cerebral perfusion had been established, aortotomy was performed at the roots of cephalic arteries to the distal aorta in order to preserve the recurrent and the left phrenic nerves, and then the aorta was transected at the level of the distal anastomosis. One-quarter of the posterior aortic wall was resected (Fig 2).
This procedure prevents the palsy of the recurrent and the left phrenic nerves, which remain attached to the residual distal aortic wall. The root of the left subclavian artery was ligated for the perfusion of left vertebral artery. The intercostal arteries were then ligated to control bleeding. The open distal anastomosis was performed with a 2-0 Tevdek everting mattress suture (Fig 3).
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Fig 3. Schematic of surgical technique 3. Distal anastomosis of the branched arch graft through median sternotomy.
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The vascular prosthesis used in all patients was a commercially available collagen-pretreated aortic arch graft with four limbs (Hemashield Branched graft; Meadox Medical, Oakland, NJ). For patients with a normal descending aorta, a 22-F balloon aortic occlusion catheter was inserted into the descending aorta and visceral perfusion was initiated through the femoral artery at 32°C. The distal anastomosisis was followed by cross-clamping the graft proximally at the anastomosis site and instituting antegrade systemic circulation with rewarmed blood from the fourth limb of the branched arch graft (cool head–warm body perfusion) [10, 11]. The proximal side of the arch graft was sutured to the stump of the ascending aorta by a 4-0 polypropylene running suture with a Teflon felt strip. The arch graft was unclamped and coronary circulation started. The bracheocephalic and left common carotid arteries were anastomosed to their respective limbs of the graft succession with a 5-0 polypropylene running suture. After selective cerebral perfusion was terminated, the left subclavian artery was reconstructed by graft-graft anastomosis by a 5-0 polypropylene running suture (Fig 4).
The patient was weaned from cardiopulmonary bypass after the anastomoses were completed. At that point, the fourth limb of the arch graft, which was used for antegrade systemic perfusion, was resected.
In the LAT group, the patient was given endotracheal intubation with a double-lumen tube to obtain deflation of the left lung. The patient was then positioned on an operating table with the chest rotated 20 degrees from supine toward the right. The combined approach was used if the distal anastomosis level was predicted to be below the seventh vertebra, as predicted from the preoperative computed tomographic (CT) scan; the left anterolateral thoracotomy was performed according to the level of distal anastomosis (Table 1). The operative procedure was the same, except for the additional left anterolateral thoracotomy and the procedure for the distal anastomosis. The distal anastomosis was performed using the 3-0 polypropylene running suture with a Teflon felt strip after the graft was put through the native descending aorta, providing a good visual field.
Statistical analysis
Continuous data are expressed as means ± standard deviation. Continuous variables are compared by paired or unpaired t tests and the Mann-Whitney rank-sum test where applicable. For analysis of the period of respiratory support, peroral intake, and frequency of analgesia, the median value was used because the data were not normally distributed. All analyses were performed using the Statview v4.5 statistical package (Abacus Concepts Inc, Berkeley, CA) and Sigmastat software.
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Results
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In-hospital mortality, morbidity, and late mortality
There were no in-hospital deaths. Permanent neurological dysfunction, defined as permanent neurological deficits with localizing neurological signs and a corresponding new defect observed on CT scan, occurred in only 1 of 32 patients (3.1%). Temporary neurological dysfunction, defined as postoperative confusion, convulsion, and delirium with negative CT results and complete resolution of symptoms before discharge, occurred in 1 patient (3.1%). Early morbidity included pulmonary failure in 2 patients. The first patient was 71-old-year woman in the LAT group who had also undergone Bentall’s operation, in whom Enterococcus faecalis was detected from the mediastinal drain. A reoperation was performed for continuous washing with saline, and postoperative minitrack support was required for suction of sputum. The other patient, a 72-old-year woman in the median group, required 43 days of respiratory support for low output syndrome and respiratory failure. There was no paraplegia in this series.
Two patients (6.3%) in the median group died in the late postoperative period. One died of worsening of pneumonia and renal failure. The other died suddenly at home from an unknown cause.
Extracorporeal circulation data
There was no significant difference between the LAT group and median group in total pump time (158 ± 25 vs 164 ± 37 minutes, respectively), cardiac ischemic time (84 ± 20 vs 87 ± 18 minutes), or selective cerebral perfusion time (101 ± 14 vs 109 ± 28 minutes).
Level of distal anastomosis
The distal anastomosis level was significantly lower in the LAT group than in the median group (thoracic vertebra, 5.6 ± 0.59 vs 7.1 ± 1.5, p = 0.0015).
Clinical outcomes
The operative time was significantly longer in the LAT group (496 ± 85 vs 391 ± 86 minutes, p = 0.0038), and more blood was transfused (35 ± 27 vs 20 ± 17 U, p = 0.0164) than in the median group; of note, 1 patient in the LAT group had a ruptured aneurysm. There was no significant difference between the two groups in the beginning of peroral intake after operation or in the duration of the hospital stay (Table 2).
Postoperative inflammatory reactions in the LAT and median group were similar, as judged by the maximum C-reactive protein level (29.1 ± 8.7 vs 25.3 ± 15.2 mg/dL, respectively) and how long the C-reactive protein level was greater than 2.0 mg/dL (27.8 ± 8.5 vs 21.7 ± 15.2 days, respectively). There were no significant differences in the maximum values of total bilirubin (4.3 ± 2.5 vs 4.6 ± 8.0 mg/dL) and creatinine (1.1 ± 0.4 vs 1.2 ± 0.5 mg/dL).
Postoperative respiratory function
New hoarseness occurred postoperatively only in the patient who had a ruptured aneurysm. No patients had left phrenic nerve palsy. Respiratory support was required for 0 to 2.3 days in the LAT group and for 0 to 1 day in the median group; the median values were not significantly different between the two groups (p = 0.221). Postoperative spirography showed no differences in the postoperative vital capacity (79% ± 20% vs 90% ± 19%) or in the 1-second forced expiratory volumes (85% ± 21% vs 64% ± 11%,).
Postoperative wound pain
There was no significant difference between the two groups in regard to the frequency needed for an analgesic drug, such as nonsteroidal antiinflammatory, to alleviate postoperative wound pain. The time of analgesic therapy was 0 to 4.0 hours in the LAT group and 0 to 2.3 hours in the median group (median 0 vs 0 hour, p = 0.734).
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Comment
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Preserving the anterior wall of the distal aortic arch during total arch replacement avoids injury to the left recurrent and phrenic nerves [9] and significantly reduces postoperative respiratory hoarseness, aspiration pneumonia, and phrenic nerve palsy. However, when this procedure is used to treat a thoracic aortic aneurysm involving the distal arch and proximal descending aorta, it is occasionally extremely difficult to perform the distal anastomosis. We first encountered this problem in a patient who had a chronic type B dissection that had enlarged from the ascending aorta to the descending aorta at the eighth thoracic vertebrae. We could not complete the total arch replacement through a median sternotomy because it was technically too difficult to obtain the distal anastomosis. However, we were able to complete the distal anastomosis through a left anterolateral thoracotomy at the fourth intercostal space. The patient’s recovery was very smooth.
As a result, we decided to modify our procedure by placing a graft that extended to proximal descending aorta. This modification provided us a good view of the whole heart as well as of the entire aorta. It also enabled us to perform the distal anastomosis without increasing postoperative pain or slowing wound healing, even though the operative time was longer and transfusion volume was larger than the median approach. A bilateral anterior thoracotomy "clamshell" incision [8] in conjunction with an extended left thoracotomy [12] provides excellent exposure of the entire aorta and intercostal artery, but not such a good view of the whole heart. Thus, the use of a median sternotomy and a left anterolateral thoracotomy approach may be advantageous in patients with thoracic aortic aneurysms and complex heart disease.
Previously, this combined surgical approach for thoracic aortic aneurysm was thought to be too invasive [13]. Our findings in this study, however, showed no significant differences in respiratory function or in the inflammatory response between patients who underwent total arch replacement through a median sternotomy and those who also had a left anterolateral thoracotomy. As might be expected, aortic replacement extending to the proximal descending aorta is more complicated and difficult than less extensive replacements. Our initial refinement in procedure, which enabled us to preserve the anterior wall in the distal aortic arch, may also have made the distal anastomosis technically more difficult in a greater number of cases. Although further examination is needed, our current method might be better than previous methods because it makes possible the extended replacement of the aorta.
We were able to decrease the hospital mortality and perioperative neurological dysfunction in total arch replacement by preserving the anterior wall in the aortic distal arch. Total arch replacement through median sternotomy plus left anterolateral thoracotomy allowed expeditious and extended replacement of the thoracic aorta without increasing postoperative respiratory complications. Our technique provides a good visual field of the entire aorta and heart, making it useful for patients with thoracic aortic aneurysms involving the arch and descending aorta.
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References
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Abstract
Introduction
