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Occlusions and Aneurysms of the Cervical Carotid Arteries
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Occlusions and Aneurysms of the Cervical Carotid Arteries F. HENRY ELLIS, JR., M.D. JACK P. WHISNANT, M.D.
SURGICAL TREATMENT of arteriosclerosis consists primarily of removing the diseased arterial segments and restoring circulation. The attention of surgeons interested in these procedures was drawn first to the thoracic and aorto-iliac vessels. Gradually, with increasing experience, efforts have been extended to include treatment of the branches of the major arteries, prominent among which are the cervical carotid arteries. Although a variety of vascular conditions in the neck may require surgical treatment, those lesions secondary to arteriosclerosis-namely, occlusions and aneurysms-are of particular importance and will constitute the basis of this brief report. OCCLUSIVE LESIONS OF THE CAROTID ARTERIES
Only in recent years has there been full appreciation of the fact that many cases of local cerebral ischemia are due to segmental occlusive lesions of the extracranial cerebral vessels. DeBakey and associates found that 41 per cent of patients alleged to have had cerebral ischemic symptoms had arteriographic evidence of extra cranial occlusive arterial lesions. This is approximately the same percentage as that found by Martin and associates in routine necropsy specimens from persons more than 50 years old at death. The disease characteristically has been segmental, and therefore surgical procedures (chiefly endarterectomy and bypass grafts) have been employed for more than ten years. 5 , 10 Stimulated by these early reports, we initiated several years ago a study of the surgical treatment of extracranial cerebrovascular occlusive arterial disease. 12 The long and successful experience of Millikan and associates with anticoagulant therapy of certain categories of cerebrovascular disease demanded that any new form of therapy be evaluated carefully and compared with the existing one. One of the purposes of our study, therefore, was to compare the results of anticoagulant and of
:1
1145
1146
F.
HENRY ELLIS, JR., JACK
P.
WHISNANT
surgical therapy. To make such a comparison meaningful, the status of each patient must be defined clearly. Definitions
Three main categories of ischemic cerebrovascular disease have been described previously:15 (1) incipient stroke (intermittent insufficiency), characterized by brief attacks of focal cerebral ischemia with intervals of normality between; (2) progressing stroke, in which the attending physician witnesses a gradual increase of neurologic deficit over a period that rarely exceeds 24 hours; and (3) completed stroke, in which the neurologic deficit is stable but may be expected to improve spontaneously. These categories refer to the clinical status of the patient and are not absolute, for the patient may change categories or actually be in more than one category at one time. Furthermore, this grouping makes no reference to the presence or absence of any specific type of arterial lesion. Selection of Patients
The diagnosis of ischemic cerebrovascular disease is based on the patient's history and the results of clinical examination. Arteriography is performed only on those patients presumed to be reasonably suitable candidates for operation. Since the purpose of surgical therapy is to prevent the development of stroke or the worsening of an existing mild neurologic deficit, patients with severe incapacitating neurologic deficits are considered unsuitable for operation. Patients with completed stroke have not been benefited by restoration of cerebral circulation on the involved side. Even without treatment, some spontaneous improvement is to be expected during the ensuing weeks and months, and we have seen no evidence of improvement in surgically treated patients that might not have occurred spontaneously. Experience with the surgical treatment of patients with progressing stroke is small, but there is some evidence to suggest that operation may be hazardous. 1 Anticoagulant therapy, often used as an emergency measure, is our current preference for initial treatment, at least. On the other hand, Crawford and co-workers have reported almost uniformly good results among 27 surgically treated patients with progressing stroke. Patients with incipient stroke in whom a single stenotic vessel rather than an occluded vessel is demonstrated arteriographically are the best candidates for operation. In these patients, circulation almost always can be re-established at relatively low risk. Elimination of attacks and reduction of the incidence of ultimate cerebral infarction constitute the goal of therapy. The younger patient is preferred for surgical treatment, since prolonged medical management may prove cumbersome over the years, and also the disease is more likely to be localized in the younger patient. The
Occlusions and Aneurysms of the Cervical Carotid Arteries
1147
patient's general health should be considered and operation not advised if widespread vascular disease or other life-threatening diseases are present. The purpose of arteriography is to demonstrate the site and extent of the arterial lesion. This procedure is not without risk, particularly when a direct injection of the left carotid artery is done. (Visualization of the right carotid artery usually is accomplished by retrograde injection of the right subclavian artery.) Accordingly, on occasion we have advised operation for a stenotic lesion of the left carotid artery on clinical evidence alone. At present, arteriographic evidence of intracranial occlusive disease appears to be a contraindication to operation. Stenosis of one or both carotid arteries may be present without leading to symptoms.13 Thus far, however, clinically significant arterial stenosis has not been found by arteriography or surgical exploration in a patient with normal retinal-artery pressure and without a bruit over the involved vessel. These findings therefore argue against the desirability of recommending operation. The finding of an occluded rather than a stenotic artery in the neck is considered now a contraindication to operation unless it can be established that the period of occlusion has been not more than 24 hours. We have been able to restore normal circulation in only a very small percentage of patients with occluded arteries, and it has been accomplished at some risk of distal embolization. This, of course, does not apply to vessels occluded at or near the origin from the aortic arch, for a bypass graft is eminently satisfactory in this location. Occasionally a patient with occlusion of one internal carotid artery and stenosis of the other has ischemic symptoms from the cerebral hemisphere or eye ipsilateral to the occluded artery. In these instances, operation may be directed at the stenotic artery with the goal of increasing the total amount of blood flowing to the brain. Technique of Endarterectomy of the Carotid Artery
Various arterial lesions may hinder cerebral circulation, and corrective operative procedures vary with the location of the lesion. Some of these are diagrammed in Figure 1. With rare exceptions, endarterectomy of the common carotid artery at its bifurcation or of the internal carotid artery (Fig. 2) has been employed to restore cerebral circulation in patients with incipient stroke (intermittent cerebrovascular insufficiency). The technique of this procedure will be described. Operation is performed under combined local and regional anesthesia. Only by having the patient awake can the surgeon ascertain the safety of temporary occlusion of the carotid artery without the use of shunts. A longitudinal incision is made along the anterior margin of the sternocleidomastoid muscle. The incision is deepened to expose the carotid artery, with care not to injure the hypoglossal nerve. Manipulation of
1148
F.
HENRY ELLIS, JR., JACK
P.
WHISNANT
Bypass -graft
Fig. 1. Repairs for various cerebrovascular lesions. (Reproduced with permission from Bernatz, P. E.: Surgical technics. In: Symposium on Surgical Treatment of Extracranial Occlusive Cerebrovascular Disease. Proc. Staff Meet., Mayo Clin. 35: 487-492 [Aug. 17]1960.)
the carotid vessel is minimized to avoid dislodgement of emboli. The postoperative recognition of mild to moderate neurologic defects in some patients, coupled with the postoperative finding of bright embolic plaques in the retina,6 has suggested that embolization of the atherosclerotic lesion may take place during the operation. The patient's blood pressure is increased to 180 mm. Hg systolic, and the carotid artery is occluded for ten minutes after heparinization. During this period, observations for evidence of neurologic disturbance are made. Most patients readily tolerate the period of occlusion. The clamps then are removed and preparations for endarterectomy are initiated. The common, external, and internal carotid arteries are occluded and a longitudinal incision is made over the plaque (Fig. 2). A cleavage plane is established and endarterectomy is begun. Occasionally a transverse incision facilitates the procedure. After completion of the endarterectomy, the distal intima of the internal carotid artery may require reattachment with a few fine silk sutures. The arteriotomy incision is
Occlusions and Aneurysms of the Cervical Carotid Arteries
1149
l-(
~ -.9,
Prosthetic or venous patch
~
( d:::l
1,
Fig. 2. Types of arteriotomy employed in endarterectomy of the internal or common carotid artery. (Reproduced with permission from Allen, E. V., Barker, N. W. and Hines, E. A., Jr.: Peripheral Vascular Diseases. Ed. 3. Philadelphia, W. B. Saunders Company, 1962.)
closed with running fine silk sutures while the open vessel is irrigated intermittently with heparin solution to remove any clot or debris that may have accumulated. With careful suturing, the use of patch grafts to enlarge the internal carotid is rarely required. The clamps are removed -the distal ones being released first-and cerebral circulation is restored. Hexadimethrine bromide (Polybrene) is administered to counteract the effect of the heparin. A small Penrose drain is left in the wound for 24 to 48 hours to minimize chances of hematoma formation. Anticoagulants usually are not employed postoperatively. If neurologic symptoms develop during occlusion of the carotid artery, the clamps are removed and a shunt is utilized to maintain cerebral circulation during performance of the endarterectomy (Fig. 3). An internal shunt is preferred. The tube of proper size is slipped into each end of the arteriotomy incision and is held in place by encircling umbilical tapes. Mter endarterectomy, the tube is removed prior to placement of the last few sutures. Results of Treatment
Since operation now is restricted usually to those patients with
1150
F.
HENRY ELLIS, JR., JACK
P.
WHISNANT
,,'"
Int./ shunt
External shunt
c
Fig. 3. Temporary shunts used to support cerebral circulation. (Reproduced with permission from Bematz. P. E.: Surgical technics. In: Symposium on Surgical Treatment of Extracranial Occlusive Cerebrovascular Disease. Proc. Staff Meet., Mayo Clin. 35: 487-492 [Aug. 17]1960.)
incipient stroke, only the results in these patients will be reported. They have been reported elsewhere in greater detail.14 During the last four years, 35 patients with transient ischemic attacks have received surgical treatment. Three patients died immediately after operation: one from intracerebral hemorrhage, one from cerebral infarction, and one from myocardial infarction. Five others had neurologic deficits following operation. Four of these had primarily a disturbance of the discriminatory senses, and the fifth had a severely incapacitating deficit (Table 1). In Table 2, long-term results among these same patients are compared with those among a group of 40 patients with cerebrovascular insufficiency who were not treated medically or surgically. The untreated group are different from the surgical group in that arteriography was not done and the site and nature of the arterial lesions are unknown. Also the follow-up period is longer for the latter group. Seventy-five per cent of the surgically treated patients and 50 per cent
Occlusions and Aneurysms of the Cervical Carotid Arteries Table 1.
Immediate Results After Restoring Circulation in Patients with Incipient Stroke RESULT
NUMBER
PER CENT
Normality Neurologic deficit Death
27*
77 14
5 3
Long-Term Results of Various Methods of Treatment for Incipient Stroke
SURGICAL TREATMENT, FOLLOW-UP
6-42
i
1
I1
1j
II
100
* Ischemic episodes recurred in 3 patients. Table 2.
1
9
35
Total
~
1151
NO TREATMENT, FOLLOW-UP
12-60
MO.
MO.
ANTICOAGULANT TREATMENT, FOLLOW-UP
3-8 YEARS
RESULT
No.
%
No.
%
No.
%
Normality Neurologic deficit Death
26* 4 5
75 14
20t 13 7
50 32 18
131 4 40
75 2 23
35
100
40
100
175
100
Total
11
* Ischemic episodes recurred in 3 patients. t Ischemic episodes continued in 10 patients.
of the untreated patients were normal at the time of re-examination. Ischemic episodes occurred more than twice as often in the untreated group. That protection against cerebral infarction is afforded by the operation is evidenced by the fact that residual neurologic deficit occurred in only 11 per cent of the surgical group as compared to 32 per cent of the untreated group. The mortality rate from all causes was comparable in the two groups. Included in Table 2 are results of anticoagulant therapy in a large group of patients with incipient stroke,u Comparison of results in these patients with results in the surgically treated group is not entirely valid, for in the anticoagulant group the site of the arterial lesion was not established. Previous experience has shown that 25 per cent of patients with the clinical diagnosis of incipient stroke do not have arteriographic evidence of occlusive cerebrovascular disease,16 and the prognosis in such cases may differ from that for patients with demonstrable extracranial arterial lesions. Even so, the percentage of patients normal at re-examination was the same in the two groups. There was a higher incidence of
F.
1152
HENRY ELLIS, JR., JACK
P.
WHISNANT
cerebral infarction in the surgical group. The mortality rate was higher in the group treated with anticoagulants, but the follow-up period was longer than in the surgical group. Thus, patients with incipient stroke can be treated satisfactorily either by anticoagulants or by operation. The patients most likely to benefit from operation are those who are relatively young, who do not have other serious or life-threatening disease, who are found to have stenosis but not occlusion of either the internal or common carotid artery, and who do not have stenosis or occlusion of an intracranial artery. Furthermore, the follow-up studies show that if the operation is immediately successful and without complication, the ultimate prognosis regarding relief of symptoms and protection against cerebral infarction is good. ANEURYSMS OF THE CAROTID ARTERIES
Aneurysms of the extracranial carotid arteries are far less common than are occlusive lesions. Of approximately 2300 operations performed by the group at Baylor University for aneurysms of all parts of the extracranial arterial system, only seven involved the carotid arteries. 2 Since 1936, only six such patients have been encountered at the Mayo Clinic; two of these were treated by excision and restoration of cerebral circulation. 9 Etiology
Prior to W orld War I, syphilis was the commonest cause of cervical carotid aneurysms. During that war and subsequently, traumatic injuries predominated. The arteriosclerotic variety now predominates among surgical cases reported. The site of predilection is the bifurcation of the common carotid artery. Aneurysms of the external and internal carotid vessels are rare. Differential Diagnosis
Care must be taken in differentiating an aneurysm from a "buckling" of the common carotid artery. Buckling of the carotid artery results from elongatioh and tortuosity of the aortic arch associated with advanced arteriosclerosis. It is seen almost exclusively in women, more often on the right side than on the left, and usually hypertension is present. Chemodectoma of the carotid body also must be excluded. This tumor may exhibit pUlsation and, because of its vascularity, a continuous bruit may be heard over it. Carotid arteriography occasionally may be required for correct differentiation. Surgi~al
Treatment
In the past, surgical treatment consisted of obliterative procedures such
I~
Occlusions and Aneurysms of the Cervical Carotid Arteries
1153
Fig. 4. Aneurysm of right internal carotid artery in 40-year-old woman. a, Appearance at operation. b, End-to-end anastomosis completed. (Reproduced with permission from Raphael, H. A., Bernatz, P. E., Spittell, J. A., Jr. and Ellis, F. H., Jr.: Cervical carotid aneurysms: Treatment by excision and restoration of arterial continuity. Am. J. Surg. [In press).)
i
'1
li. I, "
I
as ligation of the vessel and aneurysmorrhaphy, no attempt being made to restore cerebral circulation. High morbidity and mortality were associated with these operations. Resection of the aneurysm and restoration of arterial circulation is now the treatment of choice. This can be accomplished by a variety of procedures. The simplest of these consists of lateral excision of the aneurysm and arteriorrhaphy, but this is feasible only in those few cases in which the neck of the aneurysm is sufficiently narrow to permit crossclamping. If the aneurysm is in the internal carotid artery, excision and direct end-to-end anastomosis often can be accomplished (Fig. 4). Aneurysms involving the common carotid artery more frequently require resection and insertion of a graft (Fig. 5). Either Dacron or Teflon is a suitable plastic substitute. An autogenous venous graft also may be used, the choice depending on the preference of the surgeon. Appropriate measures must be taken to protect the brain from anoxia when carotid aneurysms are excised. Adequate collateral circulation is not so likely to be associated with these aneurysms as with occlusive lesions of the extracranial carotid arteries. Whole-body hypothermia or internal or external shunting may be employed. The former method is attended by some risk of ventricular fibrillation in patients with arteriosclerosis, since disease of the coronary arteries may coexist. The location and size of the lesion and the surgeon's preference determine whether an internal or an external shunt is used. When properly applied, such techniques should permit resection of carotid aneurysms with restoration of cerebral circulation and without the development of neurologic deficits
1154
F.
HENRY ELLIS, JR., JACK
P.
WHISNANT
Fig. 5. Aneurysm at bifurcation of right common carotid artery in 50-year-old man. a, Operative exposure. b, Grafting completed. (Reproduced with permission from Raphael, H. A., Bernatz, P. E., Spittell, J. A., Jr. and Ellis, F. H., Jr.: Cervical carotid aneurysms: Treatment by excision and restoration of arterial continuity. Am. J. Surg. [In press].)
REFERENCES 1. Bauer, R. B., Sheehan, S., Wechsler, N. and Meyer, J. S.: Arteriographic study of sites, incidence, and treatment of arteriosclerotic cerebrovascular lesions. Neurology 12: 698-711 (Oct.) 1962. 2. Beall, A. C., Jr., Crawford, E. S., Cooley, D. A. and DeBakey, M. E.: Extracranial aneurysms of carotid artery: Report of seven cases. Postgrad. Med. 32: 93-102 (Aug.) 1962. 3. Crawford, E. S., DeBakey, M. E. and Fields, W. S.: Progressing stroke: Surgical therapy. In Millikan, C. H., Siekert, R. G. and Whisnant, J. P.: Cerebral Vascular Diseases. Transactions of the Third Conference Held Under the Auspices of the American Neurological Association and the American Heart Association, Princeton, New Jersey, January 4 to 6,1961. New York, Grune & Stratton, Inc., 1961, pp. 178-184. 4. DeBakey, M. E., Crawford, E. S., Morris, G. C., Jr. and Cooley, D. A.: Surgical consideration of occlusive disease of innominate, carotid, subclavian, and vertebral arteries. Ann. Surg. 154: 698-725 (Oct.) 1961. 5. Eastcott, H. H. G., Pickering, G. W. and Rob, C. G.: Reconstruction of internal carotid artery in patient with intermittent attacks of hemiplegia. Lancet 2: 994-996 (Nov. 13) 1954. l6. Hollenhorst, R. W.: Significance of bright plaques in retinal arterioles. J.A.M.A. I 178: 23-29 (Oct. 7) 1961. 7. Martin, M. J., Whisnant, J. P. and Sayre, G. P.: Occlusive vascular disease in extracranial cerebral circulation. Arch. Neurol. 3: 530--538 (Nov.) 1960. 8. Millikan, C. H., Siekert, R. G. and Whisnant, J. P.: Anticoagulant therapy in cerebral vascular disease: Current status. J.A.M.A. 166: 587-592 (Feb. 8) 1958.
1
1
Occlusions and Aneurysms of the Cervical Carotid Arteries
1155
9. Raphael, H. A., Bernatz, P. E., Spittell, J. A., Jr. and Ellis, F. H., Jr.: Cervical carotid aneurysms: Treatment by excision and restoration of arterial continuity. Am. J. Surg. (In press.) 10. Shimizu, K. and Sano, K.: Pulseless disease. J. Neuropath. & Clin. Neurol. 1: 37-47 (Jan.) 1951. 11. Siekert, R. G., Whisnant, J. P. and Millikan, C. H.: Surgical and anticoagulant therapy of occlusive cerebrovascular disease. Ann. Int. Med. 58: 637-641 (April) 1963. 12. Symposium on Surgical Treatment of Extracranial Occlusive Cerebrovascular Disease: Siekert, R. G.: Diagnosis and classification of focal ischemic cerebrovascular disease. Whisnant, J. P.: Selection of patients for arteriography and surgical treatment. Baker, H. L., Jr.: Cerebral arteriography: Technics and results. Bernatz, P. E.: Surgical technics. Ellis, F. H., Jr.: Results of surgical treatment. Millikan, C. H.: Concluding remarks. Proc. Staff Meet., Mayo Clin. 35: 473-479; 480-482; 482-486; 487-492; 492-498; 498-499 (Aug. 17) 1960. 13. Whisnant, J. P., Martin, M. J. and Sayre, G. P.: Atherosclerotic stenosis of cervical arteries: Clinical significance. Arch. Neurol. 5: 429-432 (Oct.) 1961. 14. Whisnant, J. P., Siekert, R. G., Bernatz, P. E. and Ellis, F. H., Jr.: Results of surgical treatment of incipient stroke. Circulation (In press.) 15. Whisnant, J. P., Siekert, R. G. and Millikan, C. H.: Appraisal of current trend toward surgical treatment of occlusive cerebrovascular disease. M. Clin. North America 44: 875-886 (July) 1960. 16. Whisnant, J. P., Siekert, R. G., Millikan, C. H. and Bernatz, P. E.: Selection of patients for surgical treatment of occlusive cerebrovascular disease. M. Clin. North America 46: 955-962 (July) 1962.
Occlusions and Aneurysms of the Cervical Carotid Arteries F. HENRY ELLIS, JR., M.D. JACK P. WHISNANT, M.D.
SURGICAL TREATMENT of arteriosclerosis consists primarily of removing the diseased arterial segments and restoring circulation. The attention of surgeons interested in these procedures was drawn first to the thoracic and aorto-iliac vessels. Gradually, with increasing experience, efforts have been extended to include treatment of the branches of the major arteries, prominent among which are the cervical carotid arteries. Although a variety of vascular conditions in the neck may require surgical treatment, those lesions secondary to arteriosclerosis-namely, occlusions and aneurysms-are of particular importance and will constitute the basis of this brief report. OCCLUSIVE LESIONS OF THE CAROTID ARTERIES
Only in recent years has there been full appreciation of the fact that many cases of local cerebral ischemia are due to segmental occlusive lesions of the extracranial cerebral vessels. DeBakey and associates found that 41 per cent of patients alleged to have had cerebral ischemic symptoms had arteriographic evidence of extra cranial occlusive arterial lesions. This is approximately the same percentage as that found by Martin and associates in routine necropsy specimens from persons more than 50 years old at death. The disease characteristically has been segmental, and therefore surgical procedures (chiefly endarterectomy and bypass grafts) have been employed for more than ten years. 5 , 10 Stimulated by these early reports, we initiated several years ago a study of the surgical treatment of extracranial cerebrovascular occlusive arterial disease. 12 The long and successful experience of Millikan and associates with anticoagulant therapy of certain categories of cerebrovascular disease demanded that any new form of therapy be evaluated carefully and compared with the existing one. One of the purposes of our study, therefore, was to compare the results of anticoagulant and of
:1
1145
1146
F.
HENRY ELLIS, JR., JACK
P.
WHISNANT
surgical therapy. To make such a comparison meaningful, the status of each patient must be defined clearly. Definitions
Three main categories of ischemic cerebrovascular disease have been described previously:15 (1) incipient stroke (intermittent insufficiency), characterized by brief attacks of focal cerebral ischemia with intervals of normality between; (2) progressing stroke, in which the attending physician witnesses a gradual increase of neurologic deficit over a period that rarely exceeds 24 hours; and (3) completed stroke, in which the neurologic deficit is stable but may be expected to improve spontaneously. These categories refer to the clinical status of the patient and are not absolute, for the patient may change categories or actually be in more than one category at one time. Furthermore, this grouping makes no reference to the presence or absence of any specific type of arterial lesion. Selection of Patients
The diagnosis of ischemic cerebrovascular disease is based on the patient's history and the results of clinical examination. Arteriography is performed only on those patients presumed to be reasonably suitable candidates for operation. Since the purpose of surgical therapy is to prevent the development of stroke or the worsening of an existing mild neurologic deficit, patients with severe incapacitating neurologic deficits are considered unsuitable for operation. Patients with completed stroke have not been benefited by restoration of cerebral circulation on the involved side. Even without treatment, some spontaneous improvement is to be expected during the ensuing weeks and months, and we have seen no evidence of improvement in surgically treated patients that might not have occurred spontaneously. Experience with the surgical treatment of patients with progressing stroke is small, but there is some evidence to suggest that operation may be hazardous. 1 Anticoagulant therapy, often used as an emergency measure, is our current preference for initial treatment, at least. On the other hand, Crawford and co-workers have reported almost uniformly good results among 27 surgically treated patients with progressing stroke. Patients with incipient stroke in whom a single stenotic vessel rather than an occluded vessel is demonstrated arteriographically are the best candidates for operation. In these patients, circulation almost always can be re-established at relatively low risk. Elimination of attacks and reduction of the incidence of ultimate cerebral infarction constitute the goal of therapy. The younger patient is preferred for surgical treatment, since prolonged medical management may prove cumbersome over the years, and also the disease is more likely to be localized in the younger patient. The
Occlusions and Aneurysms of the Cervical Carotid Arteries
1147
patient's general health should be considered and operation not advised if widespread vascular disease or other life-threatening diseases are present. The purpose of arteriography is to demonstrate the site and extent of the arterial lesion. This procedure is not without risk, particularly when a direct injection of the left carotid artery is done. (Visualization of the right carotid artery usually is accomplished by retrograde injection of the right subclavian artery.) Accordingly, on occasion we have advised operation for a stenotic lesion of the left carotid artery on clinical evidence alone. At present, arteriographic evidence of intracranial occlusive disease appears to be a contraindication to operation. Stenosis of one or both carotid arteries may be present without leading to symptoms.13 Thus far, however, clinically significant arterial stenosis has not been found by arteriography or surgical exploration in a patient with normal retinal-artery pressure and without a bruit over the involved vessel. These findings therefore argue against the desirability of recommending operation. The finding of an occluded rather than a stenotic artery in the neck is considered now a contraindication to operation unless it can be established that the period of occlusion has been not more than 24 hours. We have been able to restore normal circulation in only a very small percentage of patients with occluded arteries, and it has been accomplished at some risk of distal embolization. This, of course, does not apply to vessels occluded at or near the origin from the aortic arch, for a bypass graft is eminently satisfactory in this location. Occasionally a patient with occlusion of one internal carotid artery and stenosis of the other has ischemic symptoms from the cerebral hemisphere or eye ipsilateral to the occluded artery. In these instances, operation may be directed at the stenotic artery with the goal of increasing the total amount of blood flowing to the brain. Technique of Endarterectomy of the Carotid Artery
Various arterial lesions may hinder cerebral circulation, and corrective operative procedures vary with the location of the lesion. Some of these are diagrammed in Figure 1. With rare exceptions, endarterectomy of the common carotid artery at its bifurcation or of the internal carotid artery (Fig. 2) has been employed to restore cerebral circulation in patients with incipient stroke (intermittent cerebrovascular insufficiency). The technique of this procedure will be described. Operation is performed under combined local and regional anesthesia. Only by having the patient awake can the surgeon ascertain the safety of temporary occlusion of the carotid artery without the use of shunts. A longitudinal incision is made along the anterior margin of the sternocleidomastoid muscle. The incision is deepened to expose the carotid artery, with care not to injure the hypoglossal nerve. Manipulation of
1148
F.
HENRY ELLIS, JR., JACK
P.
WHISNANT
Bypass -graft
Fig. 1. Repairs for various cerebrovascular lesions. (Reproduced with permission from Bernatz, P. E.: Surgical technics. In: Symposium on Surgical Treatment of Extracranial Occlusive Cerebrovascular Disease. Proc. Staff Meet., Mayo Clin. 35: 487-492 [Aug. 17]1960.)
the carotid vessel is minimized to avoid dislodgement of emboli. The postoperative recognition of mild to moderate neurologic defects in some patients, coupled with the postoperative finding of bright embolic plaques in the retina,6 has suggested that embolization of the atherosclerotic lesion may take place during the operation. The patient's blood pressure is increased to 180 mm. Hg systolic, and the carotid artery is occluded for ten minutes after heparinization. During this period, observations for evidence of neurologic disturbance are made. Most patients readily tolerate the period of occlusion. The clamps then are removed and preparations for endarterectomy are initiated. The common, external, and internal carotid arteries are occluded and a longitudinal incision is made over the plaque (Fig. 2). A cleavage plane is established and endarterectomy is begun. Occasionally a transverse incision facilitates the procedure. After completion of the endarterectomy, the distal intima of the internal carotid artery may require reattachment with a few fine silk sutures. The arteriotomy incision is
Occlusions and Aneurysms of the Cervical Carotid Arteries
1149
l-(
~ -.9,
Prosthetic or venous patch
~
( d:::l
1,
Fig. 2. Types of arteriotomy employed in endarterectomy of the internal or common carotid artery. (Reproduced with permission from Allen, E. V., Barker, N. W. and Hines, E. A., Jr.: Peripheral Vascular Diseases. Ed. 3. Philadelphia, W. B. Saunders Company, 1962.)
closed with running fine silk sutures while the open vessel is irrigated intermittently with heparin solution to remove any clot or debris that may have accumulated. With careful suturing, the use of patch grafts to enlarge the internal carotid is rarely required. The clamps are removed -the distal ones being released first-and cerebral circulation is restored. Hexadimethrine bromide (Polybrene) is administered to counteract the effect of the heparin. A small Penrose drain is left in the wound for 24 to 48 hours to minimize chances of hematoma formation. Anticoagulants usually are not employed postoperatively. If neurologic symptoms develop during occlusion of the carotid artery, the clamps are removed and a shunt is utilized to maintain cerebral circulation during performance of the endarterectomy (Fig. 3). An internal shunt is preferred. The tube of proper size is slipped into each end of the arteriotomy incision and is held in place by encircling umbilical tapes. Mter endarterectomy, the tube is removed prior to placement of the last few sutures. Results of Treatment
Since operation now is restricted usually to those patients with
1150
F.
HENRY ELLIS, JR., JACK
P.
WHISNANT
,,'"
Int./ shunt
External shunt
c
Fig. 3. Temporary shunts used to support cerebral circulation. (Reproduced with permission from Bematz. P. E.: Surgical technics. In: Symposium on Surgical Treatment of Extracranial Occlusive Cerebrovascular Disease. Proc. Staff Meet., Mayo Clin. 35: 487-492 [Aug. 17]1960.)
incipient stroke, only the results in these patients will be reported. They have been reported elsewhere in greater detail.14 During the last four years, 35 patients with transient ischemic attacks have received surgical treatment. Three patients died immediately after operation: one from intracerebral hemorrhage, one from cerebral infarction, and one from myocardial infarction. Five others had neurologic deficits following operation. Four of these had primarily a disturbance of the discriminatory senses, and the fifth had a severely incapacitating deficit (Table 1). In Table 2, long-term results among these same patients are compared with those among a group of 40 patients with cerebrovascular insufficiency who were not treated medically or surgically. The untreated group are different from the surgical group in that arteriography was not done and the site and nature of the arterial lesions are unknown. Also the follow-up period is longer for the latter group. Seventy-five per cent of the surgically treated patients and 50 per cent
Occlusions and Aneurysms of the Cervical Carotid Arteries Table 1.
Immediate Results After Restoring Circulation in Patients with Incipient Stroke RESULT
NUMBER
PER CENT
Normality Neurologic deficit Death
27*
77 14
5 3
Long-Term Results of Various Methods of Treatment for Incipient Stroke
SURGICAL TREATMENT, FOLLOW-UP
6-42
i
1
I1
1j
II
100
* Ischemic episodes recurred in 3 patients. Table 2.
1
9
35
Total
~
1151
NO TREATMENT, FOLLOW-UP
12-60
MO.
MO.
ANTICOAGULANT TREATMENT, FOLLOW-UP
3-8 YEARS
RESULT
No.
%
No.
%
No.
%
Normality Neurologic deficit Death
26* 4 5
75 14
20t 13 7
50 32 18
131 4 40
75 2 23
35
100
40
100
175
100
Total
11
* Ischemic episodes recurred in 3 patients. t Ischemic episodes continued in 10 patients.
of the untreated patients were normal at the time of re-examination. Ischemic episodes occurred more than twice as often in the untreated group. That protection against cerebral infarction is afforded by the operation is evidenced by the fact that residual neurologic deficit occurred in only 11 per cent of the surgical group as compared to 32 per cent of the untreated group. The mortality rate from all causes was comparable in the two groups. Included in Table 2 are results of anticoagulant therapy in a large group of patients with incipient stroke,u Comparison of results in these patients with results in the surgically treated group is not entirely valid, for in the anticoagulant group the site of the arterial lesion was not established. Previous experience has shown that 25 per cent of patients with the clinical diagnosis of incipient stroke do not have arteriographic evidence of occlusive cerebrovascular disease,16 and the prognosis in such cases may differ from that for patients with demonstrable extracranial arterial lesions. Even so, the percentage of patients normal at re-examination was the same in the two groups. There was a higher incidence of
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cerebral infarction in the surgical group. The mortality rate was higher in the group treated with anticoagulants, but the follow-up period was longer than in the surgical group. Thus, patients with incipient stroke can be treated satisfactorily either by anticoagulants or by operation. The patients most likely to benefit from operation are those who are relatively young, who do not have other serious or life-threatening disease, who are found to have stenosis but not occlusion of either the internal or common carotid artery, and who do not have stenosis or occlusion of an intracranial artery. Furthermore, the follow-up studies show that if the operation is immediately successful and without complication, the ultimate prognosis regarding relief of symptoms and protection against cerebral infarction is good. ANEURYSMS OF THE CAROTID ARTERIES
Aneurysms of the extracranial carotid arteries are far less common than are occlusive lesions. Of approximately 2300 operations performed by the group at Baylor University for aneurysms of all parts of the extracranial arterial system, only seven involved the carotid arteries. 2 Since 1936, only six such patients have been encountered at the Mayo Clinic; two of these were treated by excision and restoration of cerebral circulation. 9 Etiology
Prior to W orld War I, syphilis was the commonest cause of cervical carotid aneurysms. During that war and subsequently, traumatic injuries predominated. The arteriosclerotic variety now predominates among surgical cases reported. The site of predilection is the bifurcation of the common carotid artery. Aneurysms of the external and internal carotid vessels are rare. Differential Diagnosis
Care must be taken in differentiating an aneurysm from a "buckling" of the common carotid artery. Buckling of the carotid artery results from elongatioh and tortuosity of the aortic arch associated with advanced arteriosclerosis. It is seen almost exclusively in women, more often on the right side than on the left, and usually hypertension is present. Chemodectoma of the carotid body also must be excluded. This tumor may exhibit pUlsation and, because of its vascularity, a continuous bruit may be heard over it. Carotid arteriography occasionally may be required for correct differentiation. Surgi~al
Treatment
In the past, surgical treatment consisted of obliterative procedures such
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Occlusions and Aneurysms of the Cervical Carotid Arteries
1153
Fig. 4. Aneurysm of right internal carotid artery in 40-year-old woman. a, Appearance at operation. b, End-to-end anastomosis completed. (Reproduced with permission from Raphael, H. A., Bernatz, P. E., Spittell, J. A., Jr. and Ellis, F. H., Jr.: Cervical carotid aneurysms: Treatment by excision and restoration of arterial continuity. Am. J. Surg. [In press).)
i
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li. I, "
I
as ligation of the vessel and aneurysmorrhaphy, no attempt being made to restore cerebral circulation. High morbidity and mortality were associated with these operations. Resection of the aneurysm and restoration of arterial circulation is now the treatment of choice. This can be accomplished by a variety of procedures. The simplest of these consists of lateral excision of the aneurysm and arteriorrhaphy, but this is feasible only in those few cases in which the neck of the aneurysm is sufficiently narrow to permit crossclamping. If the aneurysm is in the internal carotid artery, excision and direct end-to-end anastomosis often can be accomplished (Fig. 4). Aneurysms involving the common carotid artery more frequently require resection and insertion of a graft (Fig. 5). Either Dacron or Teflon is a suitable plastic substitute. An autogenous venous graft also may be used, the choice depending on the preference of the surgeon. Appropriate measures must be taken to protect the brain from anoxia when carotid aneurysms are excised. Adequate collateral circulation is not so likely to be associated with these aneurysms as with occlusive lesions of the extracranial carotid arteries. Whole-body hypothermia or internal or external shunting may be employed. The former method is attended by some risk of ventricular fibrillation in patients with arteriosclerosis, since disease of the coronary arteries may coexist. The location and size of the lesion and the surgeon's preference determine whether an internal or an external shunt is used. When properly applied, such techniques should permit resection of carotid aneurysms with restoration of cerebral circulation and without the development of neurologic deficits
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Fig. 5. Aneurysm at bifurcation of right common carotid artery in 50-year-old man. a, Operative exposure. b, Grafting completed. (Reproduced with permission from Raphael, H. A., Bernatz, P. E., Spittell, J. A., Jr. and Ellis, F. H., Jr.: Cervical carotid aneurysms: Treatment by excision and restoration of arterial continuity. Am. J. Surg. [In press].)
REFERENCES 1. Bauer, R. B., Sheehan, S., Wechsler, N. and Meyer, J. S.: Arteriographic study of sites, incidence, and treatment of arteriosclerotic cerebrovascular lesions. Neurology 12: 698-711 (Oct.) 1962. 2. Beall, A. C., Jr., Crawford, E. S., Cooley, D. A. and DeBakey, M. E.: Extracranial aneurysms of carotid artery: Report of seven cases. Postgrad. Med. 32: 93-102 (Aug.) 1962. 3. Crawford, E. S., DeBakey, M. E. and Fields, W. S.: Progressing stroke: Surgical therapy. In Millikan, C. H., Siekert, R. G. and Whisnant, J. P.: Cerebral Vascular Diseases. Transactions of the Third Conference Held Under the Auspices of the American Neurological Association and the American Heart Association, Princeton, New Jersey, January 4 to 6,1961. New York, Grune & Stratton, Inc., 1961, pp. 178-184. 4. DeBakey, M. E., Crawford, E. S., Morris, G. C., Jr. and Cooley, D. A.: Surgical consideration of occlusive disease of innominate, carotid, subclavian, and vertebral arteries. Ann. Surg. 154: 698-725 (Oct.) 1961. 5. Eastcott, H. H. G., Pickering, G. W. and Rob, C. G.: Reconstruction of internal carotid artery in patient with intermittent attacks of hemiplegia. Lancet 2: 994-996 (Nov. 13) 1954. l6. Hollenhorst, R. W.: Significance of bright plaques in retinal arterioles. J.A.M.A. I 178: 23-29 (Oct. 7) 1961. 7. Martin, M. J., Whisnant, J. P. and Sayre, G. P.: Occlusive vascular disease in extracranial cerebral circulation. Arch. Neurol. 3: 530--538 (Nov.) 1960. 8. Millikan, C. H., Siekert, R. G. and Whisnant, J. P.: Anticoagulant therapy in cerebral vascular disease: Current status. J.A.M.A. 166: 587-592 (Feb. 8) 1958.
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9. Raphael, H. A., Bernatz, P. E., Spittell, J. A., Jr. and Ellis, F. H., Jr.: Cervical carotid aneurysms: Treatment by excision and restoration of arterial continuity. Am. J. Surg. (In press.) 10. Shimizu, K. and Sano, K.: Pulseless disease. J. Neuropath. & Clin. Neurol. 1: 37-47 (Jan.) 1951. 11. Siekert, R. G., Whisnant, J. P. and Millikan, C. H.: Surgical and anticoagulant therapy of occlusive cerebrovascular disease. Ann. Int. Med. 58: 637-641 (April) 1963. 12. Symposium on Surgical Treatment of Extracranial Occlusive Cerebrovascular Disease: Siekert, R. G.: Diagnosis and classification of focal ischemic cerebrovascular disease. Whisnant, J. P.: Selection of patients for arteriography and surgical treatment. Baker, H. L., Jr.: Cerebral arteriography: Technics and results. Bernatz, P. E.: Surgical technics. Ellis, F. H., Jr.: Results of surgical treatment. Millikan, C. H.: Concluding remarks. Proc. Staff Meet., Mayo Clin. 35: 473-479; 480-482; 482-486; 487-492; 492-498; 498-499 (Aug. 17) 1960. 13. Whisnant, J. P., Martin, M. J. and Sayre, G. P.: Atherosclerotic stenosis of cervical arteries: Clinical significance. Arch. Neurol. 5: 429-432 (Oct.) 1961. 14. Whisnant, J. P., Siekert, R. G., Bernatz, P. E. and Ellis, F. H., Jr.: Results of surgical treatment of incipient stroke. Circulation (In press.) 15. Whisnant, J. P., Siekert, R. G. and Millikan, C. H.: Appraisal of current trend toward surgical treatment of occlusive cerebrovascular disease. M. Clin. North America 44: 875-886 (July) 1960. 16. Whisnant, J. P., Siekert, R. G., Millikan, C. H. and Bernatz, P. E.: Selection of patients for surgical treatment of occlusive cerebrovascular disease. M. Clin. North America 46: 955-962 (July) 1962.