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Surgical Management of Aneurysms of the Ascending Aorta: Including Those Associated with Aortic Valvular Incompetence
Surgical Management of Aneurysms of the Ascending Aorta Including Those Associated with Aortic Valvular Incompetence
DENTON A. COOLEY, M.D. ROBERT D. BLOODWELL, M.D. ARTHUR C. BEALL, JR., M.D. GRADY L. HALLMAN, M.D. MICHAEL E. DE BAKEY, M.D.
Application of the surgical principle of resection and restoration of vascular continuity by graft to aneurysms of the ascending aorta awaited the development of techniques allowing safe temporary interruption of blood flow in this region. The main limiting factors were ischemic damage to the central nervous system and acute left heart strain incident to temporary cross clamping of the ascending aorta during resection and replacement of aneurysms in this location. Temporary cardiopulmonary bypass provided a means of overcoming these limitations and permitted successful surgical management of aneurysms of the ascending aorta. Progressive expansion of these aneurysms constitutes an ever present threat of further disabling compressive effects and rupture with fatal hemorrhage. Aneurysms associated with aortic valvular incompetence are a formidable pathologic entity. In addition to extension of the aortic disease that may culminate in acute rupture or intramural dissection, the aortic insufficiency leads to progressive left ventricular failure. Effective surgical From the Cora and Webb Mading Department of Surgery, Baylor University College of Medicine, Houston, Texas Supported in part by the U. S. Public Health Service (HE-03137) (HE-05435) and (HE-05387).
1033
1034
COOLEY, BLOODWELL, BEALL, HALLMAN, DE BAKEY
Figure 1. Diagram (a) and aortogram (b) demonstrating saccular aneurysm of ascending aorta. Diagram (c) and aortogram (d) showing restored aortic continuity after resection and graft replacement of ascending aorta.
therapy can relieve cardiac failure and chest pain, and prevent rupture of the aneurysm. Aortograms (Fig. 1) combined with retrograde cardiac catheterization for recording of intracardiac pressures (Fig. 2) are necessary to determine extent of the aneurysm and severity of the valvular incompetence. In patients being evaluated for aortic valvular insufficiency, an unsuspected aneurysm of the ascending aorta is often found by aortography. While some saccular aneurysms may be managed by tangential excision and lateral aortorrhaphy without interruption of aortic flow, most will require segmental aortic resection and grafting (Fig. 1). The extent and anatomic configuration of most aneurysms involving the proximal aorta
SURGICAL MANAGEMENT OF ANEURYSMS OF THE ASCENDING AORTA
1035
Figure 2. Pressure recording during retrograde left heart catheterization in patient with aneurysm and aortic valvular insufficiency. Simultaneous brachial artery pressure and catheter pressure during pullback from left ventricle to aorta. Note typical arterial pulse contour of aortic insufficiency with pressure of 150/40. Note left ventricular end-diastolic pressure nearly equal to aortic diastolic pressure (particularly during prolonged diastole) indicating wide open aortic insufficiency and left heart failure.
preclude their resection with use of temporary bypass grafts. Cardiopulmonary bypass permits interruption of aortic circulation and resection of the ascending aorta by diverting venous inflow to the heart and returning oxygenated blood to the arterial circulation, thereby maintaining adequate whole body perfusion. Myocardial support is provided and cardiac resuscitation at the completion of the aortic reconstruction is facilitated by use of the heart-lung apparatus.
PATHOGENESIS
The entire ascending thoracic aorta often is involved in the degenerative process (Fig. 3) which may extend into the aortic arch or may be confined to the proximal third of the aorta producing a "Florence flask" deformity. Accompanying annular dilatation as in annulo-aortic ectasia with cystic medial necrosis results in aortic valvular incompetence without any primary pathologic change in the valve leaflets. Among the etiologic agents producing this pathologic process are atherosclerosis, syphilis, trauma, sepsis, giant cell aortitis, and cystic medial necrosis. Isolated fusiform aneurysms are most commonly atherosclerotic in origin. Luetic aneurysms of all types are becoming rare. Aneurysms involving the base of the ascending aorta associated with valvular insufficiency are usually on the basis of cystic medial necrosis.
1036
COOLEY, BLOODWELL, BEALL, HALLMAN, DE BAKEY
Figure 3. a, Operative photograph of aneurysm of ascending aorta in 44 year old man with blood pressure of 100/46 and congestive heart failure for 2 years. b, Photograph at completion of procedure including valve replacement and resection of aneurysm with graft replacement.
Cystic medial necrosis is characterized by fragmentation of elastic fibers in the media and may result in dissecting aneurysms or diffuse aneurysmal dilatation. Occasionally the walls of the aorta show gross evidence of disruption and fragmentation of the intima and media representing healed partial dissections or incomplete rupture of the aorta. Although aneurysmal dilatation of the ascending thoracic aorta occurs in association with Marfan's syndrome, such gross and microscopic changes in the aorta often are present without associated skeletal and ocular defects or any familial pattern. Advanced medial degeneration was seen in the ascending aortas of two patients recently treated for progressive aneurysmal dilatation and aortic insufficiency who had undergone successful resection of coarctations of the aorta three and fifteen years previously. This clinical demonstration of associated defects in two regions of the aorta lends support to the concept of a congenital basis for the changes of cystic medial degeneration. A 56 year old woman demonstrated the natural history and d(;lvelopment of these lesions which may proceed in an occult fashion (Fig. 4). She experienced progressive aneurysmal enlargement of the ascending aorta and cardiac enlargement due to valvular regurgitation over a three-year period. A roentgenogram of the chest seven years previously had been normal. Although the patient was nearly asymptomatic, expansion of the aneurysm and progressive cardiomegaly prompted surgical treatment. After resection of the aneurysm of the ascending aorta, a graft was inserted and a grossly incompetent valve was replaced resulting in the patient's satisfactory recovery.
SURGICAL MANAGEMENT OF ANEURYSMS OF THE ASCENDING AORTA
1037
Figure 4. Roentgenograms of chest illustrating development of aneurysm of ascending aorta in association with aortic valvular insufficiency in 56 year old woman. Cardiac murmur discovered in 1962; cardiomegaly evident then (b) especially when compared with 1955 roentgenogram (a). Progressive cardiac enlargement and aneurysmal dilatation of ascending aorta shown by roentgenograms in 1964 (c) and 1965 (d) while patient was nearly asymptomatic.
TECHNICAL CONSIDERATIONS
Cardiopulmonary bypass is conducted under normothermic conditions using a disposable plastic bubble oxygenator* primed with 5 per cent dextrose in distilled water (Fig. 5). Employment of the hemodilution technique of whole body perfusion has provided a dependable and practical method of temporary circulatory support applicable to the treatment of all types of acquired and congenital cardiovascular defects. Despite the fact that the total perfusion time during correction of these lesions usually was longer • Travenol Laboratories, Inc., Morton Grove, Illinois.
1038
COOLEY, BLOODWELL, BEALL, HALLMAN, DE BAKEY
t
Figure 5. Diagram of technique of cardiopulmonary bypass using plastic disposable bubble oxygenator. Venous return from venae cavae flows by gravity to oxygenating column (b); blood flows through defoaming chamber (a) to arterial reservoir (c); roller-pump propels blood into arterial circulation through femoral artery. Left ventricular vent (d) returns blood to oxygenator. Coronary artery perfusion (e) obtained from arterial reservoir; pressure monitored. Pump-oxygenator primed with 5 per cent dextrose in water.
than that for most other cases, these patients were in a stable circulatory state and in good general condition at the completion of the operation The absence of postoperative coagulation problems with this technique, in addition to the use of finely woven nonporous Dacron vascular grafts, has minimized hemorrhagic complications during and following these operative procedures. Median sternotomy provides an adequate approach to aneurysms in this region and permits preparations for cardiopulmonary bypass to be readily accomplished. After suitable cannulation and initiation of bypass, the distal ascending aorta is clamped and the aneurysm is removed (Figs. 6 and 7). Particularly when the valve must be replaced, a left ventricular vent may be inserted into the cardiac apex to decompress the left heart, insuring a dry operative field and providing a means for evacuating intracardiac air at the completion of the procedure.
SURGICAL MANAGEMENT OF ANEURYSMS OF THE ASCENDING AORTA
1039
Selective coronary artery perfusion with normothermic blood from the arterial reservoir may be accomplished during open aortotomy by direct cannulation of the coronary ostia. Periods of ischemia necessary for this repair are well tolerated by the bypassed nonworking heart. When normal
Aorta cross-clamped, cQrdiopulmcmal"Y bypass b~un
Figure 6. Illustration of technique for resection and graft replacement of ascend. ing aortic aneurysm combined with aortic valve replacement. During cardiopulmonary bypass, with left ventricular venting and coronary artery perfusion, valve and aneurysm are excised and replaced with ball-valve prosthesis and nonporous Dacron vascular graft-
1040
COOLEY, BLOODWELL, BEALL, HALLMAN, DE BAKEY
Figure 7. Illustration of method of valve replacement and aneurysm removal when direct anastomosis can be used for reconstruction. Application in cases of aortic valvular regurgitation due to annulo-aortic ectasia presenting "Florence flask" deformity of ascending aorta.
coronary flow is reinstituted following closure of the aorta and removal of the distal clamp, effective myocardial function usually returns promptly. Direct current electric countershock will correct ventricular fibrillation when cardiac action resumes in this rhythm. Careful dissection during removal of the aneurysm is important to avoid injury to the adjacent structures such as the pulmonary artery to which these aneurysms usually are adherent. The dilated sinuses of Valsalva, which are frequently involved, are trimmed away preserving the coronary artery ostia and a proximal cuff of aorta for subsequent anastomosis. An alternate method is to incise the anterior wall of the aneurysm, opening it widely without resecting it, and to wrap the wall of the aneurysm about the graft at the completion of the procedure.
SURGICAL MANAGEMENT OF ANEURYSMS OF THE ASCENDING AORTA
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After resecting the aneurysm and before insertion of a graft, a prosthetic aortic valve may be inserted (Figs. 6 and 7). After seating the valve in the aortic annulus the proximal anastomosis is constructed. A Dacron graft of a suitable diameter is selected and cut diagonally to allow the proximal diameter to more nearly equal the dimensions of the proximal aorta near the annulus. Either the proximal or distal anastomosis may be performed first, whichever is more readily accessible. Aortic continuity usually is re-established by insertion of a Dacron tube graft (Fig. 6). In some cases of aortic ectasia primarily involving the base of the aorta and the sinuses of Valsalva, a direct anastomosis is possible (Fig. 7). In these cases there is a sufficient length of distal undilated aorta which can be brought down and attached to the aortic root directly making
Figure 8. Diagrams of four types of reconstruction after resection of aneurysms of ascending aorta. a, Tube graft replacement after resection of saccular aneurysm and segment of ascending aorta. b, Graft replacement of ascending aorta when sinuses of Valsalva are uninvolved and aortic valve function is unaltered. c, Direct anastomosis at base of ascending aorta and aortic valve replacement. d, Graft replacement of ascending aorta and aortic valve replacement.
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COOLEY, BLOODWELL, BEALL, HALLMAN, DE BAKEY
only one suture line necessary. Methods used in reconstructing the ascending aorta depend on the nature and extent of the aneurysm (Fig. 8).
DISCUSSION
Since resection of the entire ascending aorta during cardiopulmonary bypass was first accomplished at this institution in 1956, the feasibility of resecting aneurysms of the ascending aorta has been well established. Now all aneurysms of the ascending aorta are amenable to treatment by resection and grafting during cardiopulmonary bypass (Figs. 1,3 and 9). In the past, surgical treatment of ascending aneurysms associated with aortic valvular insufficiency was associated with a high, almost prohibitive, mortality and the risk of operation sometimes exceeded that of the untreated lesions. Aortic valve replacement combined with resection and reconstruction of the ascending aorta has been found to be the most reliable method of managing this combination of lesions. A recent series of 36 consecutive patients who underwent concomitant valve replacement and resection of the ascending aorta included only three hospital deaths, thus incurring an 8 per cent hospital mortality. The average time of cardiopulmonary bypass required for these procedures was 48 minutes, ranging between 31 and 65 minutes. Several recent technical advances have provided favorable results with low mortality. These factors include improved techniques of cardiopulmonary bypass, development of nonporous synthetic aortic grafts, and employment of effective aortic valve prostheses. The advent of reliable caged-ball prostheses has permitted wide application of valve replacement in patients with advanced valvular heart disease including aortic regurgitation. The normal support and suspension of the aortic valve leaflets often have been destroyed by an extension of the degenerative aneurysmal process into the sinuses of Valsalva in the region of the aortic annulus. Prosthetic valves provide a sturdy circumferential support at the annulus and should prevent further dilatation at the base of a progressively expanding ascending aorta. The caged ball-valve prosthesis additionally provides a reliably competent valve at completion of operation allowing more efficient cardiac function immediately.
SUMMARY
Successful surgical management of aneurysms of the ascending aorta has been made possible by several recent technical advances. Cardiopulmonary bypass provides temporary protection of the central nervous system and other vital organs during the period of circulatory interruption necessary for resection and repair of the ascending aorta. Nonporous
SURGICAL MANAGEMENT OF ANEURYSMS OF THE ASCENDING AORTA
1043
Figure 9. Roentgenograms of chest prior to operation (a and b) showing cardiomegaly and large aneurysm of ascending aorta in 46 year old woman with chest pain and cardiac failure for 3 years. Ascending aortogram in anteroposterior (c) and lateral (d) views showing extent of aneurysm and regurgitation of contrast medium into left ventricle. Roentgenograms after operation (e and f) showing decreased heart size and prosthetic aortic valve in place. Patient remains well 2 years after operation.
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COOLEY, BLOODWELL, BEALL, ILu.:LMAN, DE BAKEY
synthetic aortic grafts provide a satisfactory substitute for the ascending aorta with less tendency toward bleeding even in the presence of heparin which is necessary for bypass and perfusion. Employment of effective aortic valve prostheses permits reliable cardiac function when va.lve replacement must be combined with resection of the aneurysm. The threat of aortic rupture and future aortic dissection and the consequences of compressive effects are averted by resection of these aneurysms. Freedom from chest pain and relief of cardiac fa.ilure accompanies the improvement in cardiac function in those patients in whom aortic insufficiency also is corrected. Improvement in the technical aspects of surgical repair has provided an acceptably low operative risk and a favorable prognosis in this formidable clinical problem.
DENTON A. COOLEY, M.D. ROBERT D. BLOODWELL, M.D. ARTHUR C. BEALL, JR., M.D. GRADY L. HALLMAN, M.D. MICHAEL E. DE BAKEY, M.D.
Application of the surgical principle of resection and restoration of vascular continuity by graft to aneurysms of the ascending aorta awaited the development of techniques allowing safe temporary interruption of blood flow in this region. The main limiting factors were ischemic damage to the central nervous system and acute left heart strain incident to temporary cross clamping of the ascending aorta during resection and replacement of aneurysms in this location. Temporary cardiopulmonary bypass provided a means of overcoming these limitations and permitted successful surgical management of aneurysms of the ascending aorta. Progressive expansion of these aneurysms constitutes an ever present threat of further disabling compressive effects and rupture with fatal hemorrhage. Aneurysms associated with aortic valvular incompetence are a formidable pathologic entity. In addition to extension of the aortic disease that may culminate in acute rupture or intramural dissection, the aortic insufficiency leads to progressive left ventricular failure. Effective surgical From the Cora and Webb Mading Department of Surgery, Baylor University College of Medicine, Houston, Texas Supported in part by the U. S. Public Health Service (HE-03137) (HE-05435) and (HE-05387).
1033
1034
COOLEY, BLOODWELL, BEALL, HALLMAN, DE BAKEY
Figure 1. Diagram (a) and aortogram (b) demonstrating saccular aneurysm of ascending aorta. Diagram (c) and aortogram (d) showing restored aortic continuity after resection and graft replacement of ascending aorta.
therapy can relieve cardiac failure and chest pain, and prevent rupture of the aneurysm. Aortograms (Fig. 1) combined with retrograde cardiac catheterization for recording of intracardiac pressures (Fig. 2) are necessary to determine extent of the aneurysm and severity of the valvular incompetence. In patients being evaluated for aortic valvular insufficiency, an unsuspected aneurysm of the ascending aorta is often found by aortography. While some saccular aneurysms may be managed by tangential excision and lateral aortorrhaphy without interruption of aortic flow, most will require segmental aortic resection and grafting (Fig. 1). The extent and anatomic configuration of most aneurysms involving the proximal aorta
SURGICAL MANAGEMENT OF ANEURYSMS OF THE ASCENDING AORTA
1035
Figure 2. Pressure recording during retrograde left heart catheterization in patient with aneurysm and aortic valvular insufficiency. Simultaneous brachial artery pressure and catheter pressure during pullback from left ventricle to aorta. Note typical arterial pulse contour of aortic insufficiency with pressure of 150/40. Note left ventricular end-diastolic pressure nearly equal to aortic diastolic pressure (particularly during prolonged diastole) indicating wide open aortic insufficiency and left heart failure.
preclude their resection with use of temporary bypass grafts. Cardiopulmonary bypass permits interruption of aortic circulation and resection of the ascending aorta by diverting venous inflow to the heart and returning oxygenated blood to the arterial circulation, thereby maintaining adequate whole body perfusion. Myocardial support is provided and cardiac resuscitation at the completion of the aortic reconstruction is facilitated by use of the heart-lung apparatus.
PATHOGENESIS
The entire ascending thoracic aorta often is involved in the degenerative process (Fig. 3) which may extend into the aortic arch or may be confined to the proximal third of the aorta producing a "Florence flask" deformity. Accompanying annular dilatation as in annulo-aortic ectasia with cystic medial necrosis results in aortic valvular incompetence without any primary pathologic change in the valve leaflets. Among the etiologic agents producing this pathologic process are atherosclerosis, syphilis, trauma, sepsis, giant cell aortitis, and cystic medial necrosis. Isolated fusiform aneurysms are most commonly atherosclerotic in origin. Luetic aneurysms of all types are becoming rare. Aneurysms involving the base of the ascending aorta associated with valvular insufficiency are usually on the basis of cystic medial necrosis.
1036
COOLEY, BLOODWELL, BEALL, HALLMAN, DE BAKEY
Figure 3. a, Operative photograph of aneurysm of ascending aorta in 44 year old man with blood pressure of 100/46 and congestive heart failure for 2 years. b, Photograph at completion of procedure including valve replacement and resection of aneurysm with graft replacement.
Cystic medial necrosis is characterized by fragmentation of elastic fibers in the media and may result in dissecting aneurysms or diffuse aneurysmal dilatation. Occasionally the walls of the aorta show gross evidence of disruption and fragmentation of the intima and media representing healed partial dissections or incomplete rupture of the aorta. Although aneurysmal dilatation of the ascending thoracic aorta occurs in association with Marfan's syndrome, such gross and microscopic changes in the aorta often are present without associated skeletal and ocular defects or any familial pattern. Advanced medial degeneration was seen in the ascending aortas of two patients recently treated for progressive aneurysmal dilatation and aortic insufficiency who had undergone successful resection of coarctations of the aorta three and fifteen years previously. This clinical demonstration of associated defects in two regions of the aorta lends support to the concept of a congenital basis for the changes of cystic medial degeneration. A 56 year old woman demonstrated the natural history and d(;lvelopment of these lesions which may proceed in an occult fashion (Fig. 4). She experienced progressive aneurysmal enlargement of the ascending aorta and cardiac enlargement due to valvular regurgitation over a three-year period. A roentgenogram of the chest seven years previously had been normal. Although the patient was nearly asymptomatic, expansion of the aneurysm and progressive cardiomegaly prompted surgical treatment. After resection of the aneurysm of the ascending aorta, a graft was inserted and a grossly incompetent valve was replaced resulting in the patient's satisfactory recovery.
SURGICAL MANAGEMENT OF ANEURYSMS OF THE ASCENDING AORTA
1037
Figure 4. Roentgenograms of chest illustrating development of aneurysm of ascending aorta in association with aortic valvular insufficiency in 56 year old woman. Cardiac murmur discovered in 1962; cardiomegaly evident then (b) especially when compared with 1955 roentgenogram (a). Progressive cardiac enlargement and aneurysmal dilatation of ascending aorta shown by roentgenograms in 1964 (c) and 1965 (d) while patient was nearly asymptomatic.
TECHNICAL CONSIDERATIONS
Cardiopulmonary bypass is conducted under normothermic conditions using a disposable plastic bubble oxygenator* primed with 5 per cent dextrose in distilled water (Fig. 5). Employment of the hemodilution technique of whole body perfusion has provided a dependable and practical method of temporary circulatory support applicable to the treatment of all types of acquired and congenital cardiovascular defects. Despite the fact that the total perfusion time during correction of these lesions usually was longer • Travenol Laboratories, Inc., Morton Grove, Illinois.
1038
COOLEY, BLOODWELL, BEALL, HALLMAN, DE BAKEY
t
Figure 5. Diagram of technique of cardiopulmonary bypass using plastic disposable bubble oxygenator. Venous return from venae cavae flows by gravity to oxygenating column (b); blood flows through defoaming chamber (a) to arterial reservoir (c); roller-pump propels blood into arterial circulation through femoral artery. Left ventricular vent (d) returns blood to oxygenator. Coronary artery perfusion (e) obtained from arterial reservoir; pressure monitored. Pump-oxygenator primed with 5 per cent dextrose in water.
than that for most other cases, these patients were in a stable circulatory state and in good general condition at the completion of the operation The absence of postoperative coagulation problems with this technique, in addition to the use of finely woven nonporous Dacron vascular grafts, has minimized hemorrhagic complications during and following these operative procedures. Median sternotomy provides an adequate approach to aneurysms in this region and permits preparations for cardiopulmonary bypass to be readily accomplished. After suitable cannulation and initiation of bypass, the distal ascending aorta is clamped and the aneurysm is removed (Figs. 6 and 7). Particularly when the valve must be replaced, a left ventricular vent may be inserted into the cardiac apex to decompress the left heart, insuring a dry operative field and providing a means for evacuating intracardiac air at the completion of the procedure.
SURGICAL MANAGEMENT OF ANEURYSMS OF THE ASCENDING AORTA
1039
Selective coronary artery perfusion with normothermic blood from the arterial reservoir may be accomplished during open aortotomy by direct cannulation of the coronary ostia. Periods of ischemia necessary for this repair are well tolerated by the bypassed nonworking heart. When normal
Aorta cross-clamped, cQrdiopulmcmal"Y bypass b~un
Figure 6. Illustration of technique for resection and graft replacement of ascend. ing aortic aneurysm combined with aortic valve replacement. During cardiopulmonary bypass, with left ventricular venting and coronary artery perfusion, valve and aneurysm are excised and replaced with ball-valve prosthesis and nonporous Dacron vascular graft-
1040
COOLEY, BLOODWELL, BEALL, HALLMAN, DE BAKEY
Figure 7. Illustration of method of valve replacement and aneurysm removal when direct anastomosis can be used for reconstruction. Application in cases of aortic valvular regurgitation due to annulo-aortic ectasia presenting "Florence flask" deformity of ascending aorta.
coronary flow is reinstituted following closure of the aorta and removal of the distal clamp, effective myocardial function usually returns promptly. Direct current electric countershock will correct ventricular fibrillation when cardiac action resumes in this rhythm. Careful dissection during removal of the aneurysm is important to avoid injury to the adjacent structures such as the pulmonary artery to which these aneurysms usually are adherent. The dilated sinuses of Valsalva, which are frequently involved, are trimmed away preserving the coronary artery ostia and a proximal cuff of aorta for subsequent anastomosis. An alternate method is to incise the anterior wall of the aneurysm, opening it widely without resecting it, and to wrap the wall of the aneurysm about the graft at the completion of the procedure.
SURGICAL MANAGEMENT OF ANEURYSMS OF THE ASCENDING AORTA
1041
After resecting the aneurysm and before insertion of a graft, a prosthetic aortic valve may be inserted (Figs. 6 and 7). After seating the valve in the aortic annulus the proximal anastomosis is constructed. A Dacron graft of a suitable diameter is selected and cut diagonally to allow the proximal diameter to more nearly equal the dimensions of the proximal aorta near the annulus. Either the proximal or distal anastomosis may be performed first, whichever is more readily accessible. Aortic continuity usually is re-established by insertion of a Dacron tube graft (Fig. 6). In some cases of aortic ectasia primarily involving the base of the aorta and the sinuses of Valsalva, a direct anastomosis is possible (Fig. 7). In these cases there is a sufficient length of distal undilated aorta which can be brought down and attached to the aortic root directly making
Figure 8. Diagrams of four types of reconstruction after resection of aneurysms of ascending aorta. a, Tube graft replacement after resection of saccular aneurysm and segment of ascending aorta. b, Graft replacement of ascending aorta when sinuses of Valsalva are uninvolved and aortic valve function is unaltered. c, Direct anastomosis at base of ascending aorta and aortic valve replacement. d, Graft replacement of ascending aorta and aortic valve replacement.
1042
COOLEY, BLOODWELL, BEALL, HALLMAN, DE BAKEY
only one suture line necessary. Methods used in reconstructing the ascending aorta depend on the nature and extent of the aneurysm (Fig. 8).
DISCUSSION
Since resection of the entire ascending aorta during cardiopulmonary bypass was first accomplished at this institution in 1956, the feasibility of resecting aneurysms of the ascending aorta has been well established. Now all aneurysms of the ascending aorta are amenable to treatment by resection and grafting during cardiopulmonary bypass (Figs. 1,3 and 9). In the past, surgical treatment of ascending aneurysms associated with aortic valvular insufficiency was associated with a high, almost prohibitive, mortality and the risk of operation sometimes exceeded that of the untreated lesions. Aortic valve replacement combined with resection and reconstruction of the ascending aorta has been found to be the most reliable method of managing this combination of lesions. A recent series of 36 consecutive patients who underwent concomitant valve replacement and resection of the ascending aorta included only three hospital deaths, thus incurring an 8 per cent hospital mortality. The average time of cardiopulmonary bypass required for these procedures was 48 minutes, ranging between 31 and 65 minutes. Several recent technical advances have provided favorable results with low mortality. These factors include improved techniques of cardiopulmonary bypass, development of nonporous synthetic aortic grafts, and employment of effective aortic valve prostheses. The advent of reliable caged-ball prostheses has permitted wide application of valve replacement in patients with advanced valvular heart disease including aortic regurgitation. The normal support and suspension of the aortic valve leaflets often have been destroyed by an extension of the degenerative aneurysmal process into the sinuses of Valsalva in the region of the aortic annulus. Prosthetic valves provide a sturdy circumferential support at the annulus and should prevent further dilatation at the base of a progressively expanding ascending aorta. The caged ball-valve prosthesis additionally provides a reliably competent valve at completion of operation allowing more efficient cardiac function immediately.
SUMMARY
Successful surgical management of aneurysms of the ascending aorta has been made possible by several recent technical advances. Cardiopulmonary bypass provides temporary protection of the central nervous system and other vital organs during the period of circulatory interruption necessary for resection and repair of the ascending aorta. Nonporous
SURGICAL MANAGEMENT OF ANEURYSMS OF THE ASCENDING AORTA
1043
Figure 9. Roentgenograms of chest prior to operation (a and b) showing cardiomegaly and large aneurysm of ascending aorta in 46 year old woman with chest pain and cardiac failure for 3 years. Ascending aortogram in anteroposterior (c) and lateral (d) views showing extent of aneurysm and regurgitation of contrast medium into left ventricle. Roentgenograms after operation (e and f) showing decreased heart size and prosthetic aortic valve in place. Patient remains well 2 years after operation.
1044
COOLEY, BLOODWELL, BEALL, ILu.:LMAN, DE BAKEY
synthetic aortic grafts provide a satisfactory substitute for the ascending aorta with less tendency toward bleeding even in the presence of heparin which is necessary for bypass and perfusion. Employment of effective aortic valve prostheses permits reliable cardiac function when va.lve replacement must be combined with resection of the aneurysm. The threat of aortic rupture and future aortic dissection and the consequences of compressive effects are averted by resection of these aneurysms. Freedom from chest pain and relief of cardiac fa.ilure accompanies the improvement in cardiac function in those patients in whom aortic insufficiency also is corrected. Improvement in the technical aspects of surgical repair has provided an acceptably low operative risk and a favorable prognosis in this formidable clinical problem.