Of the 17 patients with true aneurysms, atherosclerosis was the commonest cause (N = 10), 3 patients had syphilitic aortitis, in 3 patierus Takayashu's arteritis ...
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Surgery of the thoracic aorta Recent experience at Groote Schuur and Red Cross War Memorial Children's Hospitals, Cape Town J. A. ODELL,
E. A. BECERRA,
U. VON OPPELL,
H. C. K. REICHENSPURNER,
B. REICHART Summary
28+17 -
Traumatic false aneurysms (n=8)
Between September 1984 and June 1988, 46 patients (8 traumatic rupture, 10 acute and 11 chronic dissection, 17 true aneurysms) with lesions of the thoracic aorta were managed surgically. Four patients died after surgery for acute dissection, 2 after management of chronic aneurysm and 1 after replacement of the descending aorta for a chronic degenerative aneurysm. In 2 patients the operation was complicated by· paraplegia.·
64±9-
S AIr Med J 1989; 76: 409-413.
II-
Acute dissections
t-
(n= 10)
I-
Since September 1984 an aggressive approach to lesions affecting the thoracic aorta has been practised at the University of Cape Town. The results of surgical treatment of these lesions are reported.
II-
Patients and methods Between September 1984 and June 1988, 46 patients had surgery for lesions of the thoracic aorta. There are four broad groups of lesions that require operation: trauma, acute and chronic dissection and true degenerative aneurysms. The number of patients and their ages are shown in Fig. 1. The specific aetiological factors are listed in Table 1.
50± 16-
Acute aortic dissection The De Bakey classification is more generally accepted:? type I involves the whole aorta, type Il only the ascending aorta and type III the descending aorta. The classification of the dissection is not based on the site of the intimal tear, which may be difficult to identify, but on the extent of the lesion. Department ofCardiothoracic Surgery, University of Cape
Town J. A. ODELL, M.B. CH. B., F.R.CS. E. A. BECERRA, M.C (CHILE) u. VaN OPPELL, M.B. CH.B., F.CS. (SA) (THOR.) H. C. K. REICHENSPURNER, STATE EXAMINATION (GERMA!'.ry) B. REICHART, M.D. Accepted 14 Mar 1989.
Chronic dissecting aneurysms (n =11)
t---
.-
n
t---
50±20-
Traumatic rupture/false aneurysm In these 8 patients, 6 injuries were the result of blunt trauma; 4 chronic and 2 acute - 1 followed inhalation of a pin that pierced the bronchial tree and the descending aortic wall and has been previously described, 1 and in 1 patient false aneurysm was the result of a chest stab wound. All ruptures/ false aneurysms involved the descending thoracic aorta.
t---
True aneurysms
t--
(n=17)
,---
I 10 20304050607080 Age (yrs) Fig. 1. The age distribution of patients with lesions of the thoracic aorta requiring surgery.
Of the 10 patients with acute dissections 4 were type I, 4 type Il and 2 type III - 1 of these patients developed acute aortic incompetence. On four occasions perforation into the pericardium causing cardiac tamponade occurred and 1 patient developed a haemothorax.
Chronic aortic dissection Of the 11 patients with chronic dissections - by definition a history longer than 2 weeks - 2 were type I, 5 type Il and 4 type Ill. Aortic incompetence was diagnosed in 6 instances. In 1 patient an aortic valve replacement had been done 6 months
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TABLE I. AETIOLOGICAL FACTORS Acute dissection (N= 10) Atherosclerosis Cystic media necrosis Bicuspid aortic valve Undetermined
2 2 1 5
Traumatic false aneurysms (N = 8) Blunt chest trauma Inhalation of pin Stab wound
6 1 1
Chronic aneurysms (N= 28) Atherosclerosis Cystic media necrosis Takayasu's arteritis Luetic arteritis Gonococcal arteritis Previous surgery (AVR) Undetermined
UV; 5
10*
8t 3 3 1 1 2
1.-l--1
.. 1 inflammatory disease. 3 Marfan's syndrome. AVR = aortic valve replacement
previously. On 4 occasions emergency operations were necessary because of perforation into the oesophagus, the left main bronchus, the mediastinum and the pericardium.
Fig. 2. The surgical procedures in 8 patients with traumatic ruptures of the descending aorta. Of those involving the upper descending aorta 4 were chronic and 2 acute and were the resuH of blunt trauma. The descending aorta was involved after inhalation of a pin and a stab wound.
True aneurysms Of the 17 patients with true aneurysms, atherosclerosis was the commonest cause (N = 10), 3 patients had syphilitic aortitis, in 3 patierus Takayashu's arteritis was found and in 1 patient with gonococcal prosthetic valve endocarditis an aneurysm developed on the posterior wall of the ascending aorta. In this group of patients rupture occurred twice.
Surgical management The extent of surgical repair is diagrammatically shown in Figs 2 - 5. In general, the following regimen was followed: Whenever the aortic lesion involved the ascending aorta and arch a median sternotomy was performed: lesions including the descending aorta and arch necessitated a left lateral thoracotomy extended, if necessary, anteriorly across the sternum. If only the arch was involved, the approach was either a midline sternotomy or lateral thoracotomy (the laner preferred more recently). In all patients except those with acute traumatic rupture and in 1 with rupture of an aneurysm into the oesophagus, cardiopulmonary bypass was used; the site and extent of the lesion dictating arterial and venous cannulation and whether or not circulatory arrest was used. If the lesion involved the descending aorta a number of techniques were employed: 3 patients had partial left heart bypass without an oxygenator in the circuit - the left atrial blood was returned to the left common femoral artery; in 3 patients in whom the lesion involved the left half of the arch as well as the descending thoracic aorta, cardiopulmonary bypass, profound hypothermia and circulatory arrest was used; in others partial bypass with moderate hypothermia was utilised. Whenever the aortic arch was involved (15 of 46 patients (36,2%)) circulatory arrest was established after the patient was cooled to 18°e. The safe period of time for this procedure in man is believed to be approximately 1 hour at 18°e. Table 11 shows the periods of circulatory arrest.
6-~l2--
Fig. 3. Schematic draWing of the surgical treatment of patients with acute aortic dissection.
Cardiopulmonary bypass was deliberately avoided in acute traumatic ruptures in order to prevent the use of full heparinisation in patients with other major injuries, particularly head and orthopaedic injuries. Bypass was also not used in the patient in whom rupture occurred into the oesophagus. Low-porosity woven Cooley-Dacron grafts (Medox Medical Inc., Oakland, NY, USA) pre-eloned with fibrin glue (Tissuelkit, Immuno AG, Vienna, Austria) were used to replace the aneurysmal segments. Fibrin glue was also applied over the suture lines, In patients with acute aortic dissection in whom
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