REPORTS ON THERAPY
Acute Aortic Arch Dissection: Reevaluation of the Indications for Medical and Surgical Therapy
JACK KOLFF, MD* ROBERT J. BATES, MD t SAMUEL C. BALDERMAN, MDt KAYODE SHENKOYA, MD CONSTANTINE E. ANAGNOSTOPOULOS, MD, FACC §
Chicago, Illinois
From the Cardiac Surgery Section, The University
of Chicago, Chicago, Illinois. This study was supported in part by The Combined Cardiac Research Fund, The Universityof Chicago, Chicago, Illinois. Manuscriptreceived September 10, 1976; revised manuscriptreceived November 23, 1976, accepted November 29, 1976. * Institute for Biomedical Engineering, Univarsity of Utah, Salt Lake City, Utah. 1 Present address: General Surgica! Services, Massachusetts General Hospital, Boston, Massachusetts. $ Present address: Section of Cardiopulmonary Surgery, Loyola University, Maywood, Illinois. §Established Investigator, American Heart
Association. Address for reprints: Constantine E. Anagnostopoulos, MD, The University of Chicago, 950 East
59th Street, Chicago, Illinois 60637.
Of 42 patients with dissection of the aorta, 4 had important arch involvement. Results were good in 2 patients treated medically. In two other patients wrapping the arch with a Dacron graft successfully prevented fatal hemorrhage. This technique avoids the need for arch replacement in selected cases. From this experience and a review of others a flow sheet was developed to guide decision-making in the surgical and medical management of patients with aortic dissection.
The arch of the aorta is the ugly duckling within the classification schemes of acute aortic dissection. Lying between the ascending and descending thoracic aorta, it is neither anterior nor posterior. As such, an intima] tear in this area lies between DeBakey's anatomic type II and type III. 1 It may, by extension, have the complications of either the acutely dissecting ascending or descending aorta in addition to its own unique complications secondary to occlusion of the brachiocephalic vessels. In 1934, Shennan 2 reviewed in detail 315 cases of aortic dissection; 236 cases were acute and an aortic arch intima] tear was found in 34 of these (15 percent). Fifteen of the patients (42 percent) were dead within 6 weeks compared with 92 percent of patients with dissection of the ascending aorta, a However, McFarland et a].4 reported no survivors among patients with medically treated arch dissection. Gurin et al. 5 reported in 1935 the first attempted repair of an aortic dissection (abdominal) using a reentry procedure. Abbott 6 later attempted to control dissecting thoracic aneurysms with use of a cellophane wrap. DeBakey et al. 7 used a transthoracic approach to repair thoracic dissections, and employed Shaw's method s of fenestration in the chest for the first time. Other patients in their series were treated with excision of the saccular aneurysm and suturing of the base, end to end aortic anastomosis or homograft interposition; moderate hypothermia was used in two of their six patients to protect the spinal cord from ischemic damage. Two of their three patients with aortic arch involvement died, one as the result of ventricular fibrillation and the other after persistent postoperative hypertension and further dissection with rupture into the pericardia] cavity. Early surgical intervention was proposed as the solution to acute aortic dissection. Cooley9 and Gerbode 1° and their co-workers introduced the use of left atriofemoral bypass to support spinal cord and kidney perfusion when elective transthoracic repair was undertaken; the former perfused the carotid arteries in patients with aortic arch dissection. Discouraging results with the surgical therapy of acute dissection led Wheat et a].ll in 1965 to propose an" alternate medical regimen using pharmacologic agents to decrease myocardial contractility and reduce blood pressure. They hoped that with such treatment patients would progress from an acute to a subacute or chronic stage when elective
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surgery would be technically easier and associated with a higher rate of survival. Five of their six patients were treated successfully during 9 to 15 months of follow-up and did not require surgery. The sixth patient had an intimal tear in the aortic arch and had aortic valve imcompetence after 9 months. Replacement of the ascending aorta and aortic valve was required; the dissection of the arch and descending aorta remained stablel Nine of the 32 patients of Cooley et al.9 had acute arch dissection but were operated on in the subacute stage 1 to 6 weeks later. At this time, the condition of these patients was usually worse than that of patients with a chronic aneurysm. T r e a t m e n t of class A versus class B aortic dissection: Anagnostopoulos 3 reviewed 549 cases of acute dissection collected from the literature and through questionnaires. He separated them into two groups: class A (dissection of the ascending aorta or arch) and class B (dissection not involving the ascending aorta or arch) (Table I). Short and long-term survival data in the medically and surgically treated groups were evaluated. The short-term survival rates did not differ significantly among surgically (68 lJercent) and medically (77 percent) treated patients with class A dissection. However, long-term survival in this group was significantly greater With surgical (7I percent) than with medical (50 perc~nt) therapy, thus supporting the thesis that acu.te class A dissection should be surgically treated. In class
TABLE I The " O l d " ABC Classification of Acute Dissections Class
Treatment
A. Involve ascending aorta or arch A~ with complications A 2 without complications B. Do not involve ascending aorta or arch B~ with complications B 2 without complications C. Inoperable
Medical, earliest surgery Medical, planned surgery Medical, early surgery Medical, ? elective surgery ? Medical
A, and B, Complications: Indications for Surgical Therapy 1. 2. 3. 4. 5. 6.
Resistant shock Overwhelming aortic insufficiency Saccular aneurysm Tamponade Myocardial ischemia Reversible central nervous system syndromes 7. Pulmonary artery obstruction 8. Right bundle branch block 9. Resistance to antihypertensive agents
10. Impending rupture on X-ray examination 1 1. Carotid obstruction 12. Normotension 13. Marfan's syndrome 14. Pregnancy 15. Coarctation 16. Arch dissection 17. Failure of medical therapy (pain, anuria)
A z and B 2 Indications for Medical Therapy 1. Clotted false lumen 2. No clear-cut origin of dissection visible on angiography in the absence of overwhelming aortic insufficiency or tamponade 3. A stable B 2 dissection with previously untreated hypertension and especially serious concomitant pulmonary disease 4. A stable Cedissection in a patient improperly treated since first dissection 5. Multiple simultaneous dissections 6. Unavailable ca~'diac surgical facilities
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B dissection there was no significant difference between medical or surgical therapy in short- or long-term survival rates. These results favor medical treatment for patients with dissection that does not involve the ascending aorta or arch. The natural history of aortic dissection makes immediate therapy imperative. Although only 3 percent of patients die immediately there is a i percent per hour mortality rate for the next 24 to 48 hours in untreated persons. The primary causes of death are hemorrhage, cardiac tamponade and acute cardiac failure secondary to aortic valve incompetence. Aggressive medical therapy should be instituted immediately using either continuous intravenous administration of trimethaphan (Arfonad®), 500 mg in 500 cc of 5 percent dextrose in water; sodium nitroprusside (Nipride®), 50 mg in 500 cc 5 percent dextrose in water; or a 300 mg bolus injection of diazoxide (Hyperstat®). Arterial pressure is thereby reduced to the lowest level tolerable to maintain adequate myocardial, cerebral and renal function while a definitive diagnosis is made and the point of intimal tear identified with aortography. After these procedures and hfter the clinical complications of dissection have been identified; the new classification (Table I) can be used to guide the patient toward medical or surgical treatment. Treatment of primary acute aortic arch dissection remains a troublesome problem in one of seven cases of dissection. We have not separated these cases from ascending aortic dissections, and we have considered them a Complicated type of class A1 requiring urgent surgery (A1 = ascending aortic or arch dissection with complications). Shumway, 12 who recently reclassified acute aortic dissection according to location of the intimal tear (ascending or descending aorta or arch), reported medical therapy to be uniformly unsuccessful in aortic arch dissection and recommended surgical therapy. However, Austen et al. 13 considered origin of aortic dissection in the arch a contraindication for surgery and Cooley 14 reported a small incidence of aortic rupture. McFarland et al. 4 and Liotta et al. 15 found the results of medical therapy uniformly dismal and recommended surgical repair of all such cases. In light of these differing positions and our own recent experience, we have attempted to reevaluate our previous position that aortic arch dissection is a definite indication for resection and grafting. Case Reports: Aortic Arch Dissection
In the following four case reports, the ABC scheme of classification for acute aortic dissection has been followed (Table I). We emphasize that patients in class C have irreversible multiple organ system disease (coronary, cerebral, renal, carcinous) and their condition is inoperable. Case 1
A 68 year old housewife with a history of hypertension came to the University of Chicago emergency room with the chinplaint of sudden chest and back pain and dizziness. Physical
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•ACUTE AORTIC ARCH DISSECTION--KOLFF ET AL.
examination revealed a blood pressure of 180/100 mm Hg and a pulse rate of 50/min, symmetrical in all limbs. A grade 2/6 systolic murmur was heard over the mitral valve area. A chest roentgenogram showed cardiomegaly and bilateral pleural effusions. A tentative diagnosis of acute myocardial infarction was not substantiated by changes in serum enzymes or the electrocardiogram. Three days after the onset of symptoms, the diagnosis of acute aortic dissection was made with aortography, which revealed opacification of a false lumen extending from the subclavian artery distally to the descending portion (Fig. 1). On the following day, with use of femoralfemoral bypass and a left. lateral thoracotomy, surgery was performed. The dissection was seen to have caused a massive hematoma around the arch and the ascending aorta, as well as the descending aorta. The ascending aorta from 3 cm distal to the aortic valve was replaced with a Dacron ®graft. There were no obvious intimal tears in the dissected ascending aorta, and the false lumen in the descending aorta was closed with a double sandwich of Teflon® felt (Fig. 2). Finally, the ascending aorta, the arch and descending aorta were wrapped with a large Dacron graft (Fig. 3). Postoperatively, the patient required defibrillation for recurrent ventricular tachycardia, dopamine infusion for hypotension and ventilatory support because of respiratory insufficiency. Pulmonary infiltrates developed and she was treated with anticoagulant agents for an apparent pulmonary embolus. Her hematocrit then decreased and she became anuric. A repeat aortic angiogram was suggestive of continued dissection of the thoracic and abdominal aorta with involvement of the left renal artery and extension into the iliac vessels. The patient died 1 month postoperatively. Autopsy revealed three intimal tears in the distal ascending aorta and arch and a I to 2 week old hematoma along the descending aorta and pleura of the left lung. There was a dissection of the outer third of the media extending from the distal portion of the graft to the iliac arteries. All brachiocephalic vessels contained in the wrapped dissected arch were patent.
Comment: T h i s p a t i e n t was not considered to have a class A1 dissection involving the ascending aorta and arch (Table I) until operation. T h e origin of the dis-
FIGURE 2. Case 1. Double sandwich technique of closing the false lumen using Teflon felt.
FIGURE 1. Case 1. Admission aortogram that led us to classification of this patient in class B (posterior dissection). At operation and subsequent postmortem study 4 weeks later, it was evident that the intimal tears were in relation to the arch only.
section was not a p p r e c i a t e d f r o m the a o r t o g r a m and, although the intimal tear was not repaired, the extension into the ascending a o r t a was controlled with the i n t e r p o s e d graft. I t was h o p e d t h a t dissection into the descending aorta could be controlled by using a Teflon felt sandwich to close the false lumen. However, inc o m p l e t e repair of the double lumen in the descending a o r t a led to f u r t h e r dissection and r u p t u r e coincident with anticoagulation. T h e w r a p p e d arch was not the cause of death.
FIGURE 3. Case 1. Operative repair employing final wrapping of the ascending aorta, arch and descending aorta with a large Dacron graft.
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FIGURE 4. Case 2. Aortograms. Left, on admission, showing opacification of the true and false lumens in the arch and descending aorta (arrows). Right, after 3 weeks of medical therapy, showing a single lumen.
and r u p t u r e coincident with anticoagulation. T h e w r a p p e d arch was not the cause of death. Case 2
A 50 year old man, known to be hypertensive with blood pressures averaging 180/100 mm Hg, was transferred to the University of Chicago after 6 days of hospitalization for severe lumbar and back pain relieved by antihypertensive agents. Before his transfer, recurrent back pain suggested the diagnosis of extending acute aortic dissection. Aortograms at this time disclosed extravasation of dye from the aortic lumen into a false lumen beyond the innominate artery and around the origin of the left subclavian artery (Fig. 4). Because an electrocardiogram revealed the presence of anterior myocardial ischemia, surgery was not undertaken. Subsequent coronary angiograms revealed triple vessel disease with poor distal vessels. The patient's hospital regimen consisted of 3 weeks of medical therapy with methyldopa (Aldomet®) and propranolol (Inderal®) to maintain his systolic pressure at about 120 mm Hg. A follow-up aortogram 3 weeks after admission showed a clotted false lumen and no extraaortic dye around the arch (Fig. 4). The patient was discharged on medical therapy and is well I year after discharge. C o m m e n t : This patient, originally considered to be in class A1 because of aortic arch involvement, was placed in class C after evaluation of his electrocardiogram. It is p r e s u m e d t h a t 4' days of medical t h e r a p y before angiography effectively controlled the aortic dissection. M c F a r l a n d et al. 4 p o i n t e d out t h a t six of seven patients whose aortogram showed no opacification of the false lumen survived without progressive aorta dilatation over a m e a n follow-up period of 42 months. Statistically this p a t i e n t has a 10 p e r c e n t risk of redissection, and close medical follow-up is m a n d a tory. 3 Case 3
FIGURE 5. Case 3. Aortograms. A, preoperative, showing extraaortic dye at the junction of the arch and descending aorta. B, postoperative, showing no extraaortic dye and some dilatation of the ascending aorta and arch.
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A 10 year old boy with Marfan's syndrome experienced chest and back pain while bicycling and was referred to the University of Chicago. Physical examination revealed a blood pressure of 110/60 mm Hg, a pulse rate of 70/min and a grade 3/6 diastolic murmur of aortic insufficiency. In a subsequent aortogram (Fig. 5A), extraaortic dye was seen at the junction of the arch and descending aorta and there was dilatation of the ascending aorta with slow washout of dye from a concentrically located false lumen. Grade 2 aortic regurgitation was
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evident as well as a saccular aneurysm at the junction of the descending aorta and subclavian artery. Because the patient had a class B (posterior) dissection, a left thoracotomy was performed. A massive hemorrhagic false lumen was seen around the arch, with retrograde extension in the ascending aorta and some distal descending extension. Femoral-femoral bypass was instituted, and the aortic arch and major branches were isolated. The dissection involved the arch and extended proximally to within 3 cm of the aortic valve and distally for 5 cm down the descending aorta. The ascending aorta from the coronary ostia, the aortic arch and the involved descending aorta were wrapped with a Dacron graft that was progressively constricted toward a more normal diameter (Fig. 6). Postoperatively the patient did well and was discharged on a regimen of propranolol. An aortogram obtained 3 months postoperatively (Fig. 5B) revealed no extraaortic dye, mild aortic insufficiency and some dilatation of the ascending aorta and arch.
Comment: I n a b i l i t y to define the origin of t h e dissection angiographically is an indication for medical t h e r a p y (Table I). 3 However, this p a t i e n t was categorized in class B1 because of M a r f a n ' s s y n d r o m e a n d a suggestion of a saccular aneurysm. I t was elected to t r y to p r e v e n t f u r t h e r dilatation a n d r u p t u r e b y w r a p p i n g the ascending aorta, arch and proximal descending aorta with a Dacron graft. T h e r e was no evidence t h a t intimal flaps were occluding critical branches of the aortic arch. (See A d d e n d u m . )
aortic insufficiency. At the time of transfer, physical examination revealed an elderly lady in no acute distress with a blood pressure of 140/90 mm Hg in the right arm and 110/60 mm Hg in the left arm. She was found to have a diminished left carotid pulse and a grade 2/6 aortic regurgitant murmur. Laboratory data revealed values for blood urea nitrogen of 30 rag/100 ml, serium creatine kinase of 318 units and hematocrit of 35 percent. An emergency aortogram revealed dissection of the ascending aorta, arch and descending aorta. The left carotid artery was more involved than the right, and grade 2 aortic insufficiency was noted. The celiac, superior mesenteric and left renal arteries were all supplied by the false lumen (Fig. 7). The patient's hospital course consisted of medical therapy with trimethephan and furosemide (Lasix®), needed to support her renal output. Three days after transfer her blood pressure had stabilized at 90/50 mm Hg. Upon discharge, her blood pressure was 150 to 130/90 mm Hg. A repeat aortogram 6 months later showed an intimal tear in the aortic arch with proximal and distal extension and opacification of the false lumen (Fig. 8).
Comment: Although initially eligible for classification in class A1 because of aortic insufficiency, carotid obstruction and arch dissection, this p a t i e n t was placed in class C because of general debility and an acute m y o c a r d i a l infarction.
Case 4
A 73 year old woman was transferred to the University of Chicago after I week of hospitalization for acute retrosternal and back pain. She was found to have a widening mediastinum, diagnosed as having an acute aortic dissection, and was treated with antihypertensive agents. This regimen was complicated by a history of myocardial infarction and chronic
FIGURE 6. Case 3. Operative repair of aortic dissection in a boy with Marfan's syndrome.
FIGURE 7. Case 4. Emergency aortogram showing the false lumen in the ascending aorta and perfusion of the celiac, superior mesenteric and left renal arteries from the false lumen in the abdominal aorta.
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FIGURE 8. Case 4. Follow-up aortogram performed at 6 months showing the true (left) and false (right) lumens. The intimal tear was determined to be in the aortic arch by following the course of the catheter in and out of the true lumen at the level of the aortic arch.
Discussion Definition and incidence of aortic arch dissection: Clinically, the diagnosis of d.;ssection of the aorta with "important" arch involvement as opposed to secondary involvement is made with angiography or at surgery or autopsy. Accordingly, not all patients with "important" arch dissection will be appropriately diagnosed at the outset if angiography fails to define the origin of dissection as occurred in two of our four cases. Indeed, there were indications for surgery in Cases 1 and 3. Although the preoperative diagnosis led us to use thoracotomy, the concomitant use of cardiopulmonary bypass allowed mobilization of the heart, ascending aorta and arch without much difficulty. Wrapping of the arch in both patients was successful and the death of the first patient 4 weeks after operation was related to partial repair of the descending aortic dissection. Angiographic demonstration in Patients 2 and 4 and concomitant contraindications to surgery because of severe coronary artery disease, myocardial infarction or general debility led us to utilize medical therapy with
TABLE I I F l o w Sheet f o r a T h e r a p e u t i c A p p r o a c h t o A o r t i c A r c h Dissection I. Diagnosis established with angiography A. No surgery if patient's condition is stable. Institute intensive medical therapy. B. Observe for complications of 1. Continuing p a i n / ~ S u r g e r y : wrapping operation.
/ 2. Expansion 3. Cerebral symptoms ~ Surgery: resection with prosthetic interposition. I I. Diagnosis established during an operation. A. Regardless of incision (sternotomy or thoracotomy), place on cardiopulmonary bypass and expose ascending aorta arch and descending aorta. B. If cerebral symptoms present, resect the aorta and repair with prosthetic graft. C. If no cerebral symptoms present, wrap the aorta.
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success. Repeat arteriography showed no extension of the dissection in one and healing in the other. The incidence rate of arch involvement as the only area for dissection is low and in Shennan's series 2 was only 2 percent (6 of 243) of acute aortic dissections. However, as many as 15 percent of patients may have arch involvement or dissections in association with other areas of acute aortic dissection excluding cases in which a sheath-like dissection extends from an ascending aortic intimal tear. In our own series, among 42 patients seen with acute aortic dissection between 1971 and 1976, we have identified 4 patients with the "important" arch dissections described in this report. Guidelines for m a n a g e m e n t of aortic a r c h dissection: Arch dissection is in the majority of instances a lethal disease if untreated. Although cerebral complications were thought to be so frequent as to make surgery mandatory in all patients, we have observed that it is possible to prevent these complications by appropriate radical medical management. Therefore, we propose a new flow chart (Table II) for management of patients who have important arch dissection (again excluding those who have a sheath-like extension of a primary ascending or descending aorta dissection into the arch). A. In patients whose condition is hemodynamically stable (no shock, no serious irreversible cerebral symptoms, no continuing pain with medical therapy and no expansion under observation), continuing vigorous medical therapy is indicated, provided that the diagnosis is made with angiography before the need for surgery is assessed. Subsequently, if there is continuing pain or expansion, wrapping of the aortic arch can be performed. In two such patients we observed no ill effects or extension of the wrapped dissected arch. If cerebral symptoms develop during intensive medical therapy then resection of the arch would be indicated to control the disease. 16 B. When a primary arch dissection becomes evident during operation for a preoperatively diagnosed de-
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scending or ascending aortic dissection, the patient should be placed on cardiopulmonary bypass and the arch and the ascending and proximal descending aorta exposed. The ascending and descending aorta should be transected, the double lumen reconstituted to a single lumen and a graft placed with concomitant wrapping of the arch. This presumes that no important reversible cerebral symptoms have occurred before the operation because the decision to operate is made on an angiographic interpretation that failed to detect the arch dissection. We recommend that Table II be used in therapeutic decision-making for arch dissections until a randomized study is performed of all patients with arch dissection.
rest. Roe is has suggested a washout of carbon dioxide into the femoral artery to prevent the consequences of gas embolization. Needless to say, continuing intensive medical therapy as in all cases of surgically treated dissection should be followed. In summary, we propose that no. 16 be removed from the "old" ABC classification (Table I) and that, following appropriate guidelines, both medical and surgical therapy be used in cases of arch dissection. We have initiated a prospective randomized study of medical and surgical therapy but, because of the small number of patients anticipated, it may be 3 or 4 years before significant results are accumulated. The present guidelines will assist decision-making in the interim.
Several methods for the preservation of brain and myocardial function have been described when repair of the aortic arch and branch vessels is attempted. In general, these methods have followed the principles of other cardiac surgery. Some surgeons 7,17 have used hypothermia; Griepp et al. 16 recently described the use of deep hypothermia (14 ° C) with total circulatory ar-
Addendum
The patient in Case 3 died of rupture of the unprotected descending aorta 13 months postoperatively. The section of the aorta operated upon was healed at autopsy.
References 1. DeBakey ME, Henly WS, Cooley DA, et al: Surgical management of dissecting aneurysms of the aorta. J Thorac Cardiovasc Surg 49:130-149, 1965 2. Shennan T: Dissecting aneurysms. Med Res Counc Spec Rep Set 193, London HMSO, 1934, p 138 3. Anagnoslopoulos CE: Acute Aortic Dissections. Baltimore, University Park Press, 1975, p 70 4. McFarland J, Willerson JT, Dinsmore RE, et al: The medical treatment of dissecting aortic aneurysms. N Engl J Med 286: 115-119, 1972 5. Gurln D, Bulmer JW, Derby R: Dissecting aneurysms of the aorta. Diagnosis and operative relief of acute arterial obstruction due to this cause. N Y State J Med 35:1200-1202, 1935 6. Abbott OA: Clinical experiences with application of polyethene cellophane upon aneurysms of thoracic vessels. J Thorac Surg 18:435-461, 1949 7. DeBakey ME, Cooley DA, Creeoh O Jr: Surgical considerations of dissecting aneurysms of the aorta. Ann Surg 142:586-612, 1955 8. Shaw RS: Acute dissecting aortic aneurysms: treatment by fenestration of the internal wall of the aneurysm. N Engl J Med 253: 331-333, 1955 9. Cooley DA, DeBakey ME, Morris GC Jr: Controlled extracorporeal circulation in surgical treatment of aortic aneurysm. Ann Surg
146:473-486, 1957 10. Gerbode F, Brainbridge M, Osborn JJ, et ah Traumatic thoracic aneurysms: treatment by resection and grafting with use of an extracorporeal bypass. Surgery 42:969-985, 1957 11. Wheat MW Jr, Palmer RF, Badley ID, et ah Treatment of dissecting aneurysms of the aorta without surgery. J Thorac Cardiovasc Surg 50:364-373, 1965 12. Shumway NE: Surgery for acute aortic dissection. In, Lethal Diseases of the Ascending Aorta (Anagnostopoulos EC, ed). Baltimore, University Park Press, 1975, p 124 13. Austen WG, Buckley MJ, McFarland J, et al: Therapy of dissecting aneurysms. Arch Surg 95:835-842, 1967 14. Cooley DA: Panel on acute aortic dissections. In Ref. 12, p 145 15. Liotta D, Hallman GL, Milam JD, et ah Surgical treatment of acute dissecting aneurysms of the ascending aorta. Ann Thorac Surg 12:582-592, 1971 16. Griepp RB, SUnson EB, Hollingsworth JF, et ah Prosthetic replacement of the aortic arch. J Thorac Cardiovasc Surg 70: 1051-1063, 1975 17. Nazi SA, Lewis FJ: Profound hypothermia in man. Report of a case. Ann Surg 147:264-266, 1958 18. Roe BB: Discussion. Prosthetic replacement of the aortic arch. J Thorac Cardiovasc Surg 70:1051-1063, 1975
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Acute Aortic Arch Dissection: Reevaluation of the Indications for Medical and Surgical Therapy
JACK KOLFF, MD* ROBERT J. BATES, MD t SAMUEL C. BALDERMAN, MDt KAYODE SHENKOYA, MD CONSTANTINE E. ANAGNOSTOPOULOS, MD, FACC §
Chicago, Illinois
From the Cardiac Surgery Section, The University
of Chicago, Chicago, Illinois. This study was supported in part by The Combined Cardiac Research Fund, The Universityof Chicago, Chicago, Illinois. Manuscriptreceived September 10, 1976; revised manuscriptreceived November 23, 1976, accepted November 29, 1976. * Institute for Biomedical Engineering, Univarsity of Utah, Salt Lake City, Utah. 1 Present address: General Surgica! Services, Massachusetts General Hospital, Boston, Massachusetts. $ Present address: Section of Cardiopulmonary Surgery, Loyola University, Maywood, Illinois. §Established Investigator, American Heart
Association. Address for reprints: Constantine E. Anagnostopoulos, MD, The University of Chicago, 950 East
59th Street, Chicago, Illinois 60637.
Of 42 patients with dissection of the aorta, 4 had important arch involvement. Results were good in 2 patients treated medically. In two other patients wrapping the arch with a Dacron graft successfully prevented fatal hemorrhage. This technique avoids the need for arch replacement in selected cases. From this experience and a review of others a flow sheet was developed to guide decision-making in the surgical and medical management of patients with aortic dissection.
The arch of the aorta is the ugly duckling within the classification schemes of acute aortic dissection. Lying between the ascending and descending thoracic aorta, it is neither anterior nor posterior. As such, an intima] tear in this area lies between DeBakey's anatomic type II and type III. 1 It may, by extension, have the complications of either the acutely dissecting ascending or descending aorta in addition to its own unique complications secondary to occlusion of the brachiocephalic vessels. In 1934, Shennan 2 reviewed in detail 315 cases of aortic dissection; 236 cases were acute and an aortic arch intima] tear was found in 34 of these (15 percent). Fifteen of the patients (42 percent) were dead within 6 weeks compared with 92 percent of patients with dissection of the ascending aorta, a However, McFarland et a].4 reported no survivors among patients with medically treated arch dissection. Gurin et al. 5 reported in 1935 the first attempted repair of an aortic dissection (abdominal) using a reentry procedure. Abbott 6 later attempted to control dissecting thoracic aneurysms with use of a cellophane wrap. DeBakey et al. 7 used a transthoracic approach to repair thoracic dissections, and employed Shaw's method s of fenestration in the chest for the first time. Other patients in their series were treated with excision of the saccular aneurysm and suturing of the base, end to end aortic anastomosis or homograft interposition; moderate hypothermia was used in two of their six patients to protect the spinal cord from ischemic damage. Two of their three patients with aortic arch involvement died, one as the result of ventricular fibrillation and the other after persistent postoperative hypertension and further dissection with rupture into the pericardia] cavity. Early surgical intervention was proposed as the solution to acute aortic dissection. Cooley9 and Gerbode 1° and their co-workers introduced the use of left atriofemoral bypass to support spinal cord and kidney perfusion when elective transthoracic repair was undertaken; the former perfused the carotid arteries in patients with aortic arch dissection. Discouraging results with the surgical therapy of acute dissection led Wheat et a].ll in 1965 to propose an" alternate medical regimen using pharmacologic agents to decrease myocardial contractility and reduce blood pressure. They hoped that with such treatment patients would progress from an acute to a subacute or chronic stage when elective
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surgery would be technically easier and associated with a higher rate of survival. Five of their six patients were treated successfully during 9 to 15 months of follow-up and did not require surgery. The sixth patient had an intimal tear in the aortic arch and had aortic valve imcompetence after 9 months. Replacement of the ascending aorta and aortic valve was required; the dissection of the arch and descending aorta remained stablel Nine of the 32 patients of Cooley et al.9 had acute arch dissection but were operated on in the subacute stage 1 to 6 weeks later. At this time, the condition of these patients was usually worse than that of patients with a chronic aneurysm. T r e a t m e n t of class A versus class B aortic dissection: Anagnostopoulos 3 reviewed 549 cases of acute dissection collected from the literature and through questionnaires. He separated them into two groups: class A (dissection of the ascending aorta or arch) and class B (dissection not involving the ascending aorta or arch) (Table I). Short and long-term survival data in the medically and surgically treated groups were evaluated. The short-term survival rates did not differ significantly among surgically (68 lJercent) and medically (77 percent) treated patients with class A dissection. However, long-term survival in this group was significantly greater With surgical (7I percent) than with medical (50 perc~nt) therapy, thus supporting the thesis that acu.te class A dissection should be surgically treated. In class
TABLE I The " O l d " ABC Classification of Acute Dissections Class
Treatment
A. Involve ascending aorta or arch A~ with complications A 2 without complications B. Do not involve ascending aorta or arch B~ with complications B 2 without complications C. Inoperable
Medical, earliest surgery Medical, planned surgery Medical, early surgery Medical, ? elective surgery ? Medical
A, and B, Complications: Indications for Surgical Therapy 1. 2. 3. 4. 5. 6.
Resistant shock Overwhelming aortic insufficiency Saccular aneurysm Tamponade Myocardial ischemia Reversible central nervous system syndromes 7. Pulmonary artery obstruction 8. Right bundle branch block 9. Resistance to antihypertensive agents
10. Impending rupture on X-ray examination 1 1. Carotid obstruction 12. Normotension 13. Marfan's syndrome 14. Pregnancy 15. Coarctation 16. Arch dissection 17. Failure of medical therapy (pain, anuria)
A z and B 2 Indications for Medical Therapy 1. Clotted false lumen 2. No clear-cut origin of dissection visible on angiography in the absence of overwhelming aortic insufficiency or tamponade 3. A stable B 2 dissection with previously untreated hypertension and especially serious concomitant pulmonary disease 4. A stable Cedissection in a patient improperly treated since first dissection 5. Multiple simultaneous dissections 6. Unavailable ca~'diac surgical facilities
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B dissection there was no significant difference between medical or surgical therapy in short- or long-term survival rates. These results favor medical treatment for patients with dissection that does not involve the ascending aorta or arch. The natural history of aortic dissection makes immediate therapy imperative. Although only 3 percent of patients die immediately there is a i percent per hour mortality rate for the next 24 to 48 hours in untreated persons. The primary causes of death are hemorrhage, cardiac tamponade and acute cardiac failure secondary to aortic valve incompetence. Aggressive medical therapy should be instituted immediately using either continuous intravenous administration of trimethaphan (Arfonad®), 500 mg in 500 cc of 5 percent dextrose in water; sodium nitroprusside (Nipride®), 50 mg in 500 cc 5 percent dextrose in water; or a 300 mg bolus injection of diazoxide (Hyperstat®). Arterial pressure is thereby reduced to the lowest level tolerable to maintain adequate myocardial, cerebral and renal function while a definitive diagnosis is made and the point of intimal tear identified with aortography. After these procedures and hfter the clinical complications of dissection have been identified; the new classification (Table I) can be used to guide the patient toward medical or surgical treatment. Treatment of primary acute aortic arch dissection remains a troublesome problem in one of seven cases of dissection. We have not separated these cases from ascending aortic dissections, and we have considered them a Complicated type of class A1 requiring urgent surgery (A1 = ascending aortic or arch dissection with complications). Shumway, 12 who recently reclassified acute aortic dissection according to location of the intimal tear (ascending or descending aorta or arch), reported medical therapy to be uniformly unsuccessful in aortic arch dissection and recommended surgical therapy. However, Austen et al. 13 considered origin of aortic dissection in the arch a contraindication for surgery and Cooley 14 reported a small incidence of aortic rupture. McFarland et al. 4 and Liotta et al. 15 found the results of medical therapy uniformly dismal and recommended surgical repair of all such cases. In light of these differing positions and our own recent experience, we have attempted to reevaluate our previous position that aortic arch dissection is a definite indication for resection and grafting. Case Reports: Aortic Arch Dissection
In the following four case reports, the ABC scheme of classification for acute aortic dissection has been followed (Table I). We emphasize that patients in class C have irreversible multiple organ system disease (coronary, cerebral, renal, carcinous) and their condition is inoperable. Case 1
A 68 year old housewife with a history of hypertension came to the University of Chicago emergency room with the chinplaint of sudden chest and back pain and dizziness. Physical
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examination revealed a blood pressure of 180/100 mm Hg and a pulse rate of 50/min, symmetrical in all limbs. A grade 2/6 systolic murmur was heard over the mitral valve area. A chest roentgenogram showed cardiomegaly and bilateral pleural effusions. A tentative diagnosis of acute myocardial infarction was not substantiated by changes in serum enzymes or the electrocardiogram. Three days after the onset of symptoms, the diagnosis of acute aortic dissection was made with aortography, which revealed opacification of a false lumen extending from the subclavian artery distally to the descending portion (Fig. 1). On the following day, with use of femoralfemoral bypass and a left. lateral thoracotomy, surgery was performed. The dissection was seen to have caused a massive hematoma around the arch and the ascending aorta, as well as the descending aorta. The ascending aorta from 3 cm distal to the aortic valve was replaced with a Dacron ®graft. There were no obvious intimal tears in the dissected ascending aorta, and the false lumen in the descending aorta was closed with a double sandwich of Teflon® felt (Fig. 2). Finally, the ascending aorta, the arch and descending aorta were wrapped with a large Dacron graft (Fig. 3). Postoperatively, the patient required defibrillation for recurrent ventricular tachycardia, dopamine infusion for hypotension and ventilatory support because of respiratory insufficiency. Pulmonary infiltrates developed and she was treated with anticoagulant agents for an apparent pulmonary embolus. Her hematocrit then decreased and she became anuric. A repeat aortic angiogram was suggestive of continued dissection of the thoracic and abdominal aorta with involvement of the left renal artery and extension into the iliac vessels. The patient died 1 month postoperatively. Autopsy revealed three intimal tears in the distal ascending aorta and arch and a I to 2 week old hematoma along the descending aorta and pleura of the left lung. There was a dissection of the outer third of the media extending from the distal portion of the graft to the iliac arteries. All brachiocephalic vessels contained in the wrapped dissected arch were patent.
Comment: T h i s p a t i e n t was not considered to have a class A1 dissection involving the ascending aorta and arch (Table I) until operation. T h e origin of the dis-
FIGURE 2. Case 1. Double sandwich technique of closing the false lumen using Teflon felt.
FIGURE 1. Case 1. Admission aortogram that led us to classification of this patient in class B (posterior dissection). At operation and subsequent postmortem study 4 weeks later, it was evident that the intimal tears were in relation to the arch only.
section was not a p p r e c i a t e d f r o m the a o r t o g r a m and, although the intimal tear was not repaired, the extension into the ascending a o r t a was controlled with the i n t e r p o s e d graft. I t was h o p e d t h a t dissection into the descending aorta could be controlled by using a Teflon felt sandwich to close the false lumen. However, inc o m p l e t e repair of the double lumen in the descending a o r t a led to f u r t h e r dissection and r u p t u r e coincident with anticoagulation. T h e w r a p p e d arch was not the cause of death.
FIGURE 3. Case 1. Operative repair employing final wrapping of the ascending aorta, arch and descending aorta with a large Dacron graft.
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FIGURE 4. Case 2. Aortograms. Left, on admission, showing opacification of the true and false lumens in the arch and descending aorta (arrows). Right, after 3 weeks of medical therapy, showing a single lumen.
and r u p t u r e coincident with anticoagulation. T h e w r a p p e d arch was not the cause of death. Case 2
A 50 year old man, known to be hypertensive with blood pressures averaging 180/100 mm Hg, was transferred to the University of Chicago after 6 days of hospitalization for severe lumbar and back pain relieved by antihypertensive agents. Before his transfer, recurrent back pain suggested the diagnosis of extending acute aortic dissection. Aortograms at this time disclosed extravasation of dye from the aortic lumen into a false lumen beyond the innominate artery and around the origin of the left subclavian artery (Fig. 4). Because an electrocardiogram revealed the presence of anterior myocardial ischemia, surgery was not undertaken. Subsequent coronary angiograms revealed triple vessel disease with poor distal vessels. The patient's hospital regimen consisted of 3 weeks of medical therapy with methyldopa (Aldomet®) and propranolol (Inderal®) to maintain his systolic pressure at about 120 mm Hg. A follow-up aortogram 3 weeks after admission showed a clotted false lumen and no extraaortic dye around the arch (Fig. 4). The patient was discharged on medical therapy and is well I year after discharge. C o m m e n t : This patient, originally considered to be in class A1 because of aortic arch involvement, was placed in class C after evaluation of his electrocardiogram. It is p r e s u m e d t h a t 4' days of medical t h e r a p y before angiography effectively controlled the aortic dissection. M c F a r l a n d et al. 4 p o i n t e d out t h a t six of seven patients whose aortogram showed no opacification of the false lumen survived without progressive aorta dilatation over a m e a n follow-up period of 42 months. Statistically this p a t i e n t has a 10 p e r c e n t risk of redissection, and close medical follow-up is m a n d a tory. 3 Case 3
FIGURE 5. Case 3. Aortograms. A, preoperative, showing extraaortic dye at the junction of the arch and descending aorta. B, postoperative, showing no extraaortic dye and some dilatation of the ascending aorta and arch.
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A 10 year old boy with Marfan's syndrome experienced chest and back pain while bicycling and was referred to the University of Chicago. Physical examination revealed a blood pressure of 110/60 mm Hg, a pulse rate of 70/min and a grade 3/6 diastolic murmur of aortic insufficiency. In a subsequent aortogram (Fig. 5A), extraaortic dye was seen at the junction of the arch and descending aorta and there was dilatation of the ascending aorta with slow washout of dye from a concentrically located false lumen. Grade 2 aortic regurgitation was
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evident as well as a saccular aneurysm at the junction of the descending aorta and subclavian artery. Because the patient had a class B (posterior) dissection, a left thoracotomy was performed. A massive hemorrhagic false lumen was seen around the arch, with retrograde extension in the ascending aorta and some distal descending extension. Femoral-femoral bypass was instituted, and the aortic arch and major branches were isolated. The dissection involved the arch and extended proximally to within 3 cm of the aortic valve and distally for 5 cm down the descending aorta. The ascending aorta from the coronary ostia, the aortic arch and the involved descending aorta were wrapped with a Dacron graft that was progressively constricted toward a more normal diameter (Fig. 6). Postoperatively the patient did well and was discharged on a regimen of propranolol. An aortogram obtained 3 months postoperatively (Fig. 5B) revealed no extraaortic dye, mild aortic insufficiency and some dilatation of the ascending aorta and arch.
Comment: I n a b i l i t y to define the origin of t h e dissection angiographically is an indication for medical t h e r a p y (Table I). 3 However, this p a t i e n t was categorized in class B1 because of M a r f a n ' s s y n d r o m e a n d a suggestion of a saccular aneurysm. I t was elected to t r y to p r e v e n t f u r t h e r dilatation a n d r u p t u r e b y w r a p p i n g the ascending aorta, arch and proximal descending aorta with a Dacron graft. T h e r e was no evidence t h a t intimal flaps were occluding critical branches of the aortic arch. (See A d d e n d u m . )
aortic insufficiency. At the time of transfer, physical examination revealed an elderly lady in no acute distress with a blood pressure of 140/90 mm Hg in the right arm and 110/60 mm Hg in the left arm. She was found to have a diminished left carotid pulse and a grade 2/6 aortic regurgitant murmur. Laboratory data revealed values for blood urea nitrogen of 30 rag/100 ml, serium creatine kinase of 318 units and hematocrit of 35 percent. An emergency aortogram revealed dissection of the ascending aorta, arch and descending aorta. The left carotid artery was more involved than the right, and grade 2 aortic insufficiency was noted. The celiac, superior mesenteric and left renal arteries were all supplied by the false lumen (Fig. 7). The patient's hospital course consisted of medical therapy with trimethephan and furosemide (Lasix®), needed to support her renal output. Three days after transfer her blood pressure had stabilized at 90/50 mm Hg. Upon discharge, her blood pressure was 150 to 130/90 mm Hg. A repeat aortogram 6 months later showed an intimal tear in the aortic arch with proximal and distal extension and opacification of the false lumen (Fig. 8).
Comment: Although initially eligible for classification in class A1 because of aortic insufficiency, carotid obstruction and arch dissection, this p a t i e n t was placed in class C because of general debility and an acute m y o c a r d i a l infarction.
Case 4
A 73 year old woman was transferred to the University of Chicago after I week of hospitalization for acute retrosternal and back pain. She was found to have a widening mediastinum, diagnosed as having an acute aortic dissection, and was treated with antihypertensive agents. This regimen was complicated by a history of myocardial infarction and chronic
FIGURE 6. Case 3. Operative repair of aortic dissection in a boy with Marfan's syndrome.
FIGURE 7. Case 4. Emergency aortogram showing the false lumen in the ascending aorta and perfusion of the celiac, superior mesenteric and left renal arteries from the false lumen in the abdominal aorta.
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FIGURE 8. Case 4. Follow-up aortogram performed at 6 months showing the true (left) and false (right) lumens. The intimal tear was determined to be in the aortic arch by following the course of the catheter in and out of the true lumen at the level of the aortic arch.
Discussion Definition and incidence of aortic arch dissection: Clinically, the diagnosis of d.;ssection of the aorta with "important" arch involvement as opposed to secondary involvement is made with angiography or at surgery or autopsy. Accordingly, not all patients with "important" arch dissection will be appropriately diagnosed at the outset if angiography fails to define the origin of dissection as occurred in two of our four cases. Indeed, there were indications for surgery in Cases 1 and 3. Although the preoperative diagnosis led us to use thoracotomy, the concomitant use of cardiopulmonary bypass allowed mobilization of the heart, ascending aorta and arch without much difficulty. Wrapping of the arch in both patients was successful and the death of the first patient 4 weeks after operation was related to partial repair of the descending aortic dissection. Angiographic demonstration in Patients 2 and 4 and concomitant contraindications to surgery because of severe coronary artery disease, myocardial infarction or general debility led us to utilize medical therapy with
TABLE I I F l o w Sheet f o r a T h e r a p e u t i c A p p r o a c h t o A o r t i c A r c h Dissection I. Diagnosis established with angiography A. No surgery if patient's condition is stable. Institute intensive medical therapy. B. Observe for complications of 1. Continuing p a i n / ~ S u r g e r y : wrapping operation.
/ 2. Expansion 3. Cerebral symptoms ~ Surgery: resection with prosthetic interposition. I I. Diagnosis established during an operation. A. Regardless of incision (sternotomy or thoracotomy), place on cardiopulmonary bypass and expose ascending aorta arch and descending aorta. B. If cerebral symptoms present, resect the aorta and repair with prosthetic graft. C. If no cerebral symptoms present, wrap the aorta.
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success. Repeat arteriography showed no extension of the dissection in one and healing in the other. The incidence rate of arch involvement as the only area for dissection is low and in Shennan's series 2 was only 2 percent (6 of 243) of acute aortic dissections. However, as many as 15 percent of patients may have arch involvement or dissections in association with other areas of acute aortic dissection excluding cases in which a sheath-like dissection extends from an ascending aortic intimal tear. In our own series, among 42 patients seen with acute aortic dissection between 1971 and 1976, we have identified 4 patients with the "important" arch dissections described in this report. Guidelines for m a n a g e m e n t of aortic a r c h dissection: Arch dissection is in the majority of instances a lethal disease if untreated. Although cerebral complications were thought to be so frequent as to make surgery mandatory in all patients, we have observed that it is possible to prevent these complications by appropriate radical medical management. Therefore, we propose a new flow chart (Table II) for management of patients who have important arch dissection (again excluding those who have a sheath-like extension of a primary ascending or descending aorta dissection into the arch). A. In patients whose condition is hemodynamically stable (no shock, no serious irreversible cerebral symptoms, no continuing pain with medical therapy and no expansion under observation), continuing vigorous medical therapy is indicated, provided that the diagnosis is made with angiography before the need for surgery is assessed. Subsequently, if there is continuing pain or expansion, wrapping of the aortic arch can be performed. In two such patients we observed no ill effects or extension of the wrapped dissected arch. If cerebral symptoms develop during intensive medical therapy then resection of the arch would be indicated to control the disease. 16 B. When a primary arch dissection becomes evident during operation for a preoperatively diagnosed de-
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scending or ascending aortic dissection, the patient should be placed on cardiopulmonary bypass and the arch and the ascending and proximal descending aorta exposed. The ascending and descending aorta should be transected, the double lumen reconstituted to a single lumen and a graft placed with concomitant wrapping of the arch. This presumes that no important reversible cerebral symptoms have occurred before the operation because the decision to operate is made on an angiographic interpretation that failed to detect the arch dissection. We recommend that Table II be used in therapeutic decision-making for arch dissections until a randomized study is performed of all patients with arch dissection.
rest. Roe is has suggested a washout of carbon dioxide into the femoral artery to prevent the consequences of gas embolization. Needless to say, continuing intensive medical therapy as in all cases of surgically treated dissection should be followed. In summary, we propose that no. 16 be removed from the "old" ABC classification (Table I) and that, following appropriate guidelines, both medical and surgical therapy be used in cases of arch dissection. We have initiated a prospective randomized study of medical and surgical therapy but, because of the small number of patients anticipated, it may be 3 or 4 years before significant results are accumulated. The present guidelines will assist decision-making in the interim.
Several methods for the preservation of brain and myocardial function have been described when repair of the aortic arch and branch vessels is attempted. In general, these methods have followed the principles of other cardiac surgery. Some surgeons 7,17 have used hypothermia; Griepp et al. 16 recently described the use of deep hypothermia (14 ° C) with total circulatory ar-
Addendum
The patient in Case 3 died of rupture of the unprotected descending aorta 13 months postoperatively. The section of the aorta operated upon was healed at autopsy.
References 1. DeBakey ME, Henly WS, Cooley DA, et al: Surgical management of dissecting aneurysms of the aorta. J Thorac Cardiovasc Surg 49:130-149, 1965 2. Shennan T: Dissecting aneurysms. Med Res Counc Spec Rep Set 193, London HMSO, 1934, p 138 3. Anagnoslopoulos CE: Acute Aortic Dissections. Baltimore, University Park Press, 1975, p 70 4. McFarland J, Willerson JT, Dinsmore RE, et al: The medical treatment of dissecting aortic aneurysms. N Engl J Med 286: 115-119, 1972 5. Gurln D, Bulmer JW, Derby R: Dissecting aneurysms of the aorta. Diagnosis and operative relief of acute arterial obstruction due to this cause. N Y State J Med 35:1200-1202, 1935 6. Abbott OA: Clinical experiences with application of polyethene cellophane upon aneurysms of thoracic vessels. J Thorac Surg 18:435-461, 1949 7. DeBakey ME, Cooley DA, Creeoh O Jr: Surgical considerations of dissecting aneurysms of the aorta. Ann Surg 142:586-612, 1955 8. Shaw RS: Acute dissecting aortic aneurysms: treatment by fenestration of the internal wall of the aneurysm. N Engl J Med 253: 331-333, 1955 9. Cooley DA, DeBakey ME, Morris GC Jr: Controlled extracorporeal circulation in surgical treatment of aortic aneurysm. Ann Surg
146:473-486, 1957 10. Gerbode F, Brainbridge M, Osborn JJ, et ah Traumatic thoracic aneurysms: treatment by resection and grafting with use of an extracorporeal bypass. Surgery 42:969-985, 1957 11. Wheat MW Jr, Palmer RF, Badley ID, et ah Treatment of dissecting aneurysms of the aorta without surgery. J Thorac Cardiovasc Surg 50:364-373, 1965 12. Shumway NE: Surgery for acute aortic dissection. In, Lethal Diseases of the Ascending Aorta (Anagnostopoulos EC, ed). Baltimore, University Park Press, 1975, p 124 13. Austen WG, Buckley MJ, McFarland J, et al: Therapy of dissecting aneurysms. Arch Surg 95:835-842, 1967 14. Cooley DA: Panel on acute aortic dissections. In Ref. 12, p 145 15. Liotta D, Hallman GL, Milam JD, et ah Surgical treatment of acute dissecting aneurysms of the ascending aorta. Ann Thorac Surg 12:582-592, 1971 16. Griepp RB, SUnson EB, Hollingsworth JF, et ah Prosthetic replacement of the aortic arch. J Thorac Cardiovasc Surg 70: 1051-1063, 1975 17. Nazi SA, Lewis FJ: Profound hypothermia in man. Report of a case. Ann Surg 147:264-266, 1958 18. Roe BB: Discussion. Prosthetic replacement of the aortic arch. J Thorac Cardiovasc Surg 70:1051-1063, 1975
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