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Experience with simultaneous myocardial revascularization and carotid endarterectomy
J THORAC CARDIOVASC SURG 79:922-925, 1980
Experience with simultaneous myocardial revascularization and carotid endarterectomy Fifty-four patients had coexisting stenosis of the carotid artery (70% or greater) and coronary artery disease. Simultaneous carotid endarterectomy and myocardial revascularization were done in all cases. One permanent postoperative neurologic deficit occurred (1.9%). There were no deaths. Our experience with simultaneous correction of combined carotid and coronary disease leads us to conclude that simultaneous myocardial revascularization and carotid endarterectomy have low mortality and neurologic morbidity rates. The policy at Loyola University Medical Center at this time is to routinely perform simultaneous endarterectomy and myocardial revascularization in all patients with significant coexisting carotid and coronary disease.
Philip L. Rice, M.D., Roque Pifarre, M.D., Henry J. Sullivan, M.D., Alvaro Montoya, M.D., and Mamdouh Bakhos, M.D., Maywood and Hines, Ill.
Coexistent carotid disease and coronary arterial disease present a difficult clinical management problem. The threat of myocardial infarction following carotid endarterectomy is evident, as previously cited by De Bakey and associates.' Thompson, Austin, and Patman" noted a late mortality rate of 15.7% (90/572) from myocardial infarction in patients undergoing carotid endarterectomy. Javid and associates" likewise noted a 24.5% mortality rate (12/49) in their series. Cardiac deaths associated with this procedure may be secondary to coronary artery atherosclerosis. Hypotension occurring at the time of anesthetic induction or during the operative or postoperative period can have significant hemodynamic effects on the coronary circulation, especially in the anemic or hemodiluted cardiovascular system." Increasing afterload may have a detrimental effect on cardiac performance by increasing workload and myocardial oxygen consumption.P The patient with critical coronary disease may not tolerate alterations in cardiac performance and coronary flow imposed by carotid endarterectomy, even in the best surgical centers. Selecting the patient with critical corFrom the Department of Surgery, Loyola University Medical Center, Maywood, Ill., and the Cardiopulmonary Surgery Section, Veterans Administration Hospital, Hines, Ill. Received for publication Aug. 7, 1979. Accepted for publication Nov. 14, 1979. Address for reprints: Roque Pifarre, M.D., 2160 South First Ave., Maywood, Ill. 60153.
922
onary disease is thus very important in the prevention of cardiac morbidity and death. On the other hand, major neurologic complications are seen in about 2% of all patients undergoing coronary grafting procedures." The institution of extracorporeal circulation (ECC) is associated with an initial period of hypotension, during which time mean systemic arterial pressure is low. 7 Numerous investigators have demonstrated a decrease in mean and pulsatile flow and pressure distal to lesions which produce 70% or greater reduction in the intraluminal cross-sectional area of blood vessels. 8, 9 This can be roughly estimated as a 50% reduction in the transverse diameter of the vessel. One can extrapolate from this that the hypothetical decrease in flow which occurs with the institution of ECC may initiate sudden cerebral hypoperfusion in some patients. The neurologic sequelae of this hemodynamic alteration might manifest as a "stroke syndrome," however; specific human hemodynamic studies detailing the effect of the institution of ECC on flow beyond the significant carotid arterial stenosis are not yet available. The presence of a severe stenosis in the carotid system of a patient undergoing coronary bypass thus poses a dilemma for the surgeon. He must select the approach which minimizes the risk of myocardial infarction and neurologic deficit and has a low mortality rate. Which procedure-endarterectomy or coronary bypassshould be performed first, or should they be done si-
Volume 79 Number 6
Coronary grafting and carotid endarterectomy
923
June, 1980
multaneously? We present here our experience with the simultaneous approach to this complex lesion. Patients A total of 4,023 operative procedures for myocardial revascularization were performed at Loyola University Medical Center, Maywood, Illinois, and the Hines Veterans Administration Medical Center, Hines, Illinois, from Jan. I, 1970, to Sept. 30,1979. Sixty-two patients in this series had coexistent carotid and coronary arterial disease, an incidence of 1.5%. Five of the 47 patients from the Loyola experience were women and all 15 patients from the Hines experience were men. The age distribution of the group was from 50 to 76 years. Fifty-four patients from the group of 62 patients were treated by a simultaneous approach where coronary grafting and carotid endarterectomy were done at one operation. These 54 patients were evaluated for coronary artery disease and, when indicated by history and physical examination, additional Doppler and angiographic studies were performed for evaluation of the cerebral circulation prior to the coronary operation. Twenty-six patients were studied for transient ischemic attacks (TIA) and the remaining 38 were evaluated for asymptomatic bruits. Angiography revealed cross-sectional luminal stenosis of 70% or greater in all patients. Two of the 54 patients (3.7%) had bilateral carotid disease and two patients had left main coronary stenosis. Surgical management and technique Indications for carotid endarterectomy included 70% cross-sectional luminal stenosis and/or TIA secondary to ulceration or stenosis. Indications for myocardial revascularization included accelerating angina, angina at rest, left ventricular failure from myocardial ischemic dysfunction, main left or equivalent main left coronary obstruction, and 90% proximal stenosis of the left anterior descending coronary artery alone or in combination with other vessel involvement. The operative technique is similar to that used by other groups. Anesthetic induction proceeds with full cardiac monitoring, including a percutaneously inserted Swan-Ganz catheter equipped with a thermodilution couple for cardiac output determination. Pharmacologic unloading agents are routinely used on all patients with coronary artery disease. An intra-aortic balloon is inserted if necessary under local anesthesia prior to induction, or in the postpump or postoperative period if low cardiac output supervenes. The midsternal and groin incisions are made at the same time and the sa-
phenous veins are prepared for grafting. The carotid endarterectomy is then accomplished (2,000 to 3,000 units of heparin are used) and, when completed, the neck incision is covered with a moist lap pad. An internal carotid shunt is not routinely used. If the ventricle is tolerant, the aortic anastomoses are performed prior to the institution of ECC, thus shortening the length of cardiopulmonary bypass. If ventricular strain is evident, we do not hesitate to institute cardiopulmonary bypass and perform all anastomoses with the aid of ECC. The ascending aorta is cannulated in the usual fashion after full heparinization. Hypothermia to 25° C is routinely induced. Distal saphenous-coronary anastomoses are done during cardioplegic arrest or ventricular fibrillation with intermittent aortic cross-clamping. Results Fifty-four patients were treated by a simultaneous procedure. Five postoperative complications were observed: three nonneurologic and two neurologic. One patient had postoperative pulmonary atelectasis of the left upper lobe; a second patient had anicteric hepatitis; a third patient required insertion of an intra-aortic balloon for low cardiac output syndrome. The fourth and fifth patients manifested transient hemiparesis in the postoperative period. A permanent neurologic deficit persisted in one of these patients. One patient in this group had a subsequent uneventful contralateral carotid endarterectomy 8 months after the initial simultaneous procedure. Permanent neurologic complications thus occurred in one of the 54 patients-I.9% of the total group. An average of 2.4 coronary grafts were performed (131/54). There was no death, nor did we encounter perioperative myocardial infarction. Discussion Various authors have reported their experience in dealing with coexistent carotid and coronary disease. Bernhard, Johnson, and Peterson, 10 in 1972, reported on 31 patients who were surgically treated. Fifteen of them had carotid endarterectomy prior to coronary revascularization and three (20%) died of cardiac complications before the coronary operation. Fifteen patients were treated by a simultaneous approach with no deaths and one neurologic postoperative deficit-approximately 6%. Urschel, Razzuk, and Gardner!' presented 32 patients with combined disease, eight of whom were treated with a simultaneous procedure. There were no significant complications in this group. Seventeen pa-
The Journal of Thoracic and Cardiovascular Surgery
924 Rice et al.
tients had coronary repair followed in 3 to 6 weeks by carotid endarterectomy. One stroke owing to hypotension from ventilatory problems occurred in this group. The remaining seven patients had carotid endarterectomy followed by coronary grafting in I week to I year. One postoperative myocardial infarct was encountered in this group. These patients certainly represent an excellent result, with no late deaths or significant complications occurring in a 4 to 6 year follow-up period. Mehigan and associates's have prospectively identified 6% of their coronary grafting experience with combined carotid and coronary disease. This is higher than the 1.5% noted in our operative experience and no doubt represents the importance of routine noninvasive evaluation of the carotid system in coronary grafting candidates. Mehigan's group also noted that left main coronary disease was associated with carotid stenosis in 17% of patients. Hertzer and colleagues" have reported to the Society for Vascular Surgery on their experience with 174 patients with combined disease-l.3% of their total coronary experience. Fifty-nine of these 174 patients had a staged procedure with the endarterectomy preceding the coronary grafting. It was noted that 19 of these 59 patients (32%) had significant carotid stenosis on the side opposite of the suspected diseased vessel. Postendarterectomy myocardial infarction occurred in 10% of the group and permanent neurologic deficits were present in 1.5% after carotid endarterectomy. It is more important to note, however, that the incidence of permanent neurologic deficit in the combined operation group correlated well with the degree of disease in the contralateral carotid artery. If the contralateral carotid was normal, neurologic deficit occurred in only 1.5%; if the contralateral carotid had 50% stenosis, permanent deficit occurred 6.7% of the time. This finding is noted in our series, where two of 54 patients undergoing simultaneous procedures had bilateral disease and neurologic complications were uncommon. Carey and Cukingnan 14 listed their experience with four patients undergoing simultaneous operations: one had restenosis of the endarterectomized carotid artery 3 months postoperatively and another had thrombosis of the endarterectomized segment. They encountered two postoperative neurologic deficits which they attributed to disease in the nonoperated carotid artery. Morris and co-workers" reported on 92 patients with coexistent disease. Thirty-five of these patients had a carotid endarterectomy performed before myocardial revascularization and seven (20%) died. Six of these deaths were cardiac related and one was neurologically
related. Forty-four patients in their series had a simultaneous correction with no deaths and one neurologic deficit-approximately 2.5%. From our experience and the data reported in the literature we have reached several conclusions: I. Carotid and coronary atherosclerosis coexist in approximately 1.5 to 6% of patients with coronary atherosclerosis. 2. Bilateral carotid disease occurs in 7% to 30% of these patients. 3. Cardiac complications, including death, occur in 10% to 20% of patients having staged carotid endarterectomy preceding coronary grafting. 4. Permanent neurologic deficit occurs in I % to 4% of patients undergoing simultaneous correction if unilateral carotid disease is present. 5. Neurologic deficit is more likely to occur if bilateral carotid disease is present. The best approach to the patient with combined carotid and coronary disease is not an obvious one. Okies, Macmanus, and Starr'" concluded that the surgical approach to coexistent carotid and coronary disease should be tailored to fit the individual patient. We are encouraged by the results obtained in our small group of patients. The simultaneous procedure seems to have substantial merit in our hands. The low neurologic morbidity and overall mortality rates noted in larger series support the use of the simultaneous approach. The absence of perioperative myocardial infarction in our patients reflects the low incidence observed in most major cardiac centers today. We support the use of the simultaneous approach in combined coronary and carotid disease. REFERENCES De Bakey ME, Crawford ES, Cooley DA, et al: Cerebral arterial insufficiency. One to II year results following arterial reconstruction. Ann Surg 161:921-945, 1965 2 Thompson JE, Austin DJ, Patman RD: Carotid endarterectomy for cerebrovascular insufficiency. Long-term results in 592 patients followed up to 13 years. Ann Surg 172:663-679, 1970
3 Javid H, Ostermiller WE, Henges JW, et al: Carotid endarterectomy for asymptomatic patients. Arch Surg 102:389-391, 1970
4 Geha AS, Baue AE: Graded coronary stenosis and coronary flow during acute normovolemic anemia. World J Surg 2:645-652, 1978 5 Braunwald E, Ross J, Sonnenblick EH: Myocardial Hypoxia and Ischemia, and Mechanism of Contraction of the Normal and Filling Heart, ed. 2, Boston, 1976, Little Brown & Co., pp 357-397 6 ReulGJ, Morris GC Jr, HomerJF, et al: Current concepts
Volume 79 Number 6
Coronary grafting and carotid endarterectomy
925
June. 1980
in coronary artery surgery. Ann Thorac Surg 14:243-259, 1972 7 Bartlett RH, Gazzaniga AB: Physiology and pathophysiology of extracorporeal circulation, Current Techniques in Extracorporeal Circulation, MI Ionescu, GH Wooler, eds., London, 1976, Butterworth & Co., Ltd., pp 1-44 8 May AG, DeWeese JA, Rob CG: Hemodynamic effects of arterial stenosis, Surgery 53:513-524, 1963 9 Berguer R, Hwang NC: Critical arterial stenosis. A theoretical and experimental solution. Ann Surg 180:3950, 1974 10 Bernhard JM, Johnson WD, Peterson 11: Carotid artery stenosis. Association with surgery for coronary artery disease. Arch Surg 105:837-840, 1972 11 Urschel HC, Razzuk MA, Gardner MA: Management of concomitant occlusive disease of the carotid and coronary arteries. J THORAC CARDIOVASC SURG 72:829-834, 1976
12 Mehigan JT, Buch WS, Pipkin RD, Fogarty TJ: A planned approach to coexistent cerebrovascular disease in coronary artery bypass candidates. Arch Surg 112: 14031409, 1977 13 Hertzer NR, Loop FD, Taylor PC, Beven EG: Staged and combined surgical approach to simultaneous carotid and coronary vascular disease. Surgery 84:803-811,1978 14 Carey JS, Cukingnan RA: Complications of combined brachiocephalic and coronary revascularization. Ann Thorac Surg 25:385, 1978 15 Morris GC, Ennix CL Jr, Lawrie GM, Crawford ES, Howell JF: Management of coexistent carotid and coronary artery occlusive atherosclerosis. Cleve Clin Q 45:125-127, 1977 16 Okies JE, Macmanus Q, Starr A: Myocardial revascularization and carotid endarterectomy. A combined approach. Ann Thorac Surg 23:561-564, 1977
Experience with simultaneous myocardial revascularization and carotid endarterectomy Fifty-four patients had coexisting stenosis of the carotid artery (70% or greater) and coronary artery disease. Simultaneous carotid endarterectomy and myocardial revascularization were done in all cases. One permanent postoperative neurologic deficit occurred (1.9%). There were no deaths. Our experience with simultaneous correction of combined carotid and coronary disease leads us to conclude that simultaneous myocardial revascularization and carotid endarterectomy have low mortality and neurologic morbidity rates. The policy at Loyola University Medical Center at this time is to routinely perform simultaneous endarterectomy and myocardial revascularization in all patients with significant coexisting carotid and coronary disease.
Philip L. Rice, M.D., Roque Pifarre, M.D., Henry J. Sullivan, M.D., Alvaro Montoya, M.D., and Mamdouh Bakhos, M.D., Maywood and Hines, Ill.
Coexistent carotid disease and coronary arterial disease present a difficult clinical management problem. The threat of myocardial infarction following carotid endarterectomy is evident, as previously cited by De Bakey and associates.' Thompson, Austin, and Patman" noted a late mortality rate of 15.7% (90/572) from myocardial infarction in patients undergoing carotid endarterectomy. Javid and associates" likewise noted a 24.5% mortality rate (12/49) in their series. Cardiac deaths associated with this procedure may be secondary to coronary artery atherosclerosis. Hypotension occurring at the time of anesthetic induction or during the operative or postoperative period can have significant hemodynamic effects on the coronary circulation, especially in the anemic or hemodiluted cardiovascular system." Increasing afterload may have a detrimental effect on cardiac performance by increasing workload and myocardial oxygen consumption.P The patient with critical coronary disease may not tolerate alterations in cardiac performance and coronary flow imposed by carotid endarterectomy, even in the best surgical centers. Selecting the patient with critical corFrom the Department of Surgery, Loyola University Medical Center, Maywood, Ill., and the Cardiopulmonary Surgery Section, Veterans Administration Hospital, Hines, Ill. Received for publication Aug. 7, 1979. Accepted for publication Nov. 14, 1979. Address for reprints: Roque Pifarre, M.D., 2160 South First Ave., Maywood, Ill. 60153.
922
onary disease is thus very important in the prevention of cardiac morbidity and death. On the other hand, major neurologic complications are seen in about 2% of all patients undergoing coronary grafting procedures." The institution of extracorporeal circulation (ECC) is associated with an initial period of hypotension, during which time mean systemic arterial pressure is low. 7 Numerous investigators have demonstrated a decrease in mean and pulsatile flow and pressure distal to lesions which produce 70% or greater reduction in the intraluminal cross-sectional area of blood vessels. 8, 9 This can be roughly estimated as a 50% reduction in the transverse diameter of the vessel. One can extrapolate from this that the hypothetical decrease in flow which occurs with the institution of ECC may initiate sudden cerebral hypoperfusion in some patients. The neurologic sequelae of this hemodynamic alteration might manifest as a "stroke syndrome," however; specific human hemodynamic studies detailing the effect of the institution of ECC on flow beyond the significant carotid arterial stenosis are not yet available. The presence of a severe stenosis in the carotid system of a patient undergoing coronary bypass thus poses a dilemma for the surgeon. He must select the approach which minimizes the risk of myocardial infarction and neurologic deficit and has a low mortality rate. Which procedure-endarterectomy or coronary bypassshould be performed first, or should they be done si-
Volume 79 Number 6
Coronary grafting and carotid endarterectomy
923
June, 1980
multaneously? We present here our experience with the simultaneous approach to this complex lesion. Patients A total of 4,023 operative procedures for myocardial revascularization were performed at Loyola University Medical Center, Maywood, Illinois, and the Hines Veterans Administration Medical Center, Hines, Illinois, from Jan. I, 1970, to Sept. 30,1979. Sixty-two patients in this series had coexistent carotid and coronary arterial disease, an incidence of 1.5%. Five of the 47 patients from the Loyola experience were women and all 15 patients from the Hines experience were men. The age distribution of the group was from 50 to 76 years. Fifty-four patients from the group of 62 patients were treated by a simultaneous approach where coronary grafting and carotid endarterectomy were done at one operation. These 54 patients were evaluated for coronary artery disease and, when indicated by history and physical examination, additional Doppler and angiographic studies were performed for evaluation of the cerebral circulation prior to the coronary operation. Twenty-six patients were studied for transient ischemic attacks (TIA) and the remaining 38 were evaluated for asymptomatic bruits. Angiography revealed cross-sectional luminal stenosis of 70% or greater in all patients. Two of the 54 patients (3.7%) had bilateral carotid disease and two patients had left main coronary stenosis. Surgical management and technique Indications for carotid endarterectomy included 70% cross-sectional luminal stenosis and/or TIA secondary to ulceration or stenosis. Indications for myocardial revascularization included accelerating angina, angina at rest, left ventricular failure from myocardial ischemic dysfunction, main left or equivalent main left coronary obstruction, and 90% proximal stenosis of the left anterior descending coronary artery alone or in combination with other vessel involvement. The operative technique is similar to that used by other groups. Anesthetic induction proceeds with full cardiac monitoring, including a percutaneously inserted Swan-Ganz catheter equipped with a thermodilution couple for cardiac output determination. Pharmacologic unloading agents are routinely used on all patients with coronary artery disease. An intra-aortic balloon is inserted if necessary under local anesthesia prior to induction, or in the postpump or postoperative period if low cardiac output supervenes. The midsternal and groin incisions are made at the same time and the sa-
phenous veins are prepared for grafting. The carotid endarterectomy is then accomplished (2,000 to 3,000 units of heparin are used) and, when completed, the neck incision is covered with a moist lap pad. An internal carotid shunt is not routinely used. If the ventricle is tolerant, the aortic anastomoses are performed prior to the institution of ECC, thus shortening the length of cardiopulmonary bypass. If ventricular strain is evident, we do not hesitate to institute cardiopulmonary bypass and perform all anastomoses with the aid of ECC. The ascending aorta is cannulated in the usual fashion after full heparinization. Hypothermia to 25° C is routinely induced. Distal saphenous-coronary anastomoses are done during cardioplegic arrest or ventricular fibrillation with intermittent aortic cross-clamping. Results Fifty-four patients were treated by a simultaneous procedure. Five postoperative complications were observed: three nonneurologic and two neurologic. One patient had postoperative pulmonary atelectasis of the left upper lobe; a second patient had anicteric hepatitis; a third patient required insertion of an intra-aortic balloon for low cardiac output syndrome. The fourth and fifth patients manifested transient hemiparesis in the postoperative period. A permanent neurologic deficit persisted in one of these patients. One patient in this group had a subsequent uneventful contralateral carotid endarterectomy 8 months after the initial simultaneous procedure. Permanent neurologic complications thus occurred in one of the 54 patients-I.9% of the total group. An average of 2.4 coronary grafts were performed (131/54). There was no death, nor did we encounter perioperative myocardial infarction. Discussion Various authors have reported their experience in dealing with coexistent carotid and coronary disease. Bernhard, Johnson, and Peterson, 10 in 1972, reported on 31 patients who were surgically treated. Fifteen of them had carotid endarterectomy prior to coronary revascularization and three (20%) died of cardiac complications before the coronary operation. Fifteen patients were treated by a simultaneous approach with no deaths and one neurologic postoperative deficit-approximately 6%. Urschel, Razzuk, and Gardner!' presented 32 patients with combined disease, eight of whom were treated with a simultaneous procedure. There were no significant complications in this group. Seventeen pa-
The Journal of Thoracic and Cardiovascular Surgery
924 Rice et al.
tients had coronary repair followed in 3 to 6 weeks by carotid endarterectomy. One stroke owing to hypotension from ventilatory problems occurred in this group. The remaining seven patients had carotid endarterectomy followed by coronary grafting in I week to I year. One postoperative myocardial infarct was encountered in this group. These patients certainly represent an excellent result, with no late deaths or significant complications occurring in a 4 to 6 year follow-up period. Mehigan and associates's have prospectively identified 6% of their coronary grafting experience with combined carotid and coronary disease. This is higher than the 1.5% noted in our operative experience and no doubt represents the importance of routine noninvasive evaluation of the carotid system in coronary grafting candidates. Mehigan's group also noted that left main coronary disease was associated with carotid stenosis in 17% of patients. Hertzer and colleagues" have reported to the Society for Vascular Surgery on their experience with 174 patients with combined disease-l.3% of their total coronary experience. Fifty-nine of these 174 patients had a staged procedure with the endarterectomy preceding the coronary grafting. It was noted that 19 of these 59 patients (32%) had significant carotid stenosis on the side opposite of the suspected diseased vessel. Postendarterectomy myocardial infarction occurred in 10% of the group and permanent neurologic deficits were present in 1.5% after carotid endarterectomy. It is more important to note, however, that the incidence of permanent neurologic deficit in the combined operation group correlated well with the degree of disease in the contralateral carotid artery. If the contralateral carotid was normal, neurologic deficit occurred in only 1.5%; if the contralateral carotid had 50% stenosis, permanent deficit occurred 6.7% of the time. This finding is noted in our series, where two of 54 patients undergoing simultaneous procedures had bilateral disease and neurologic complications were uncommon. Carey and Cukingnan 14 listed their experience with four patients undergoing simultaneous operations: one had restenosis of the endarterectomized carotid artery 3 months postoperatively and another had thrombosis of the endarterectomized segment. They encountered two postoperative neurologic deficits which they attributed to disease in the nonoperated carotid artery. Morris and co-workers" reported on 92 patients with coexistent disease. Thirty-five of these patients had a carotid endarterectomy performed before myocardial revascularization and seven (20%) died. Six of these deaths were cardiac related and one was neurologically
related. Forty-four patients in their series had a simultaneous correction with no deaths and one neurologic deficit-approximately 2.5%. From our experience and the data reported in the literature we have reached several conclusions: I. Carotid and coronary atherosclerosis coexist in approximately 1.5 to 6% of patients with coronary atherosclerosis. 2. Bilateral carotid disease occurs in 7% to 30% of these patients. 3. Cardiac complications, including death, occur in 10% to 20% of patients having staged carotid endarterectomy preceding coronary grafting. 4. Permanent neurologic deficit occurs in I % to 4% of patients undergoing simultaneous correction if unilateral carotid disease is present. 5. Neurologic deficit is more likely to occur if bilateral carotid disease is present. The best approach to the patient with combined carotid and coronary disease is not an obvious one. Okies, Macmanus, and Starr'" concluded that the surgical approach to coexistent carotid and coronary disease should be tailored to fit the individual patient. We are encouraged by the results obtained in our small group of patients. The simultaneous procedure seems to have substantial merit in our hands. The low neurologic morbidity and overall mortality rates noted in larger series support the use of the simultaneous approach. The absence of perioperative myocardial infarction in our patients reflects the low incidence observed in most major cardiac centers today. We support the use of the simultaneous approach in combined coronary and carotid disease. REFERENCES De Bakey ME, Crawford ES, Cooley DA, et al: Cerebral arterial insufficiency. One to II year results following arterial reconstruction. Ann Surg 161:921-945, 1965 2 Thompson JE, Austin DJ, Patman RD: Carotid endarterectomy for cerebrovascular insufficiency. Long-term results in 592 patients followed up to 13 years. Ann Surg 172:663-679, 1970
3 Javid H, Ostermiller WE, Henges JW, et al: Carotid endarterectomy for asymptomatic patients. Arch Surg 102:389-391, 1970
4 Geha AS, Baue AE: Graded coronary stenosis and coronary flow during acute normovolemic anemia. World J Surg 2:645-652, 1978 5 Braunwald E, Ross J, Sonnenblick EH: Myocardial Hypoxia and Ischemia, and Mechanism of Contraction of the Normal and Filling Heart, ed. 2, Boston, 1976, Little Brown & Co., pp 357-397 6 ReulGJ, Morris GC Jr, HomerJF, et al: Current concepts
Volume 79 Number 6
Coronary grafting and carotid endarterectomy
925
June. 1980
in coronary artery surgery. Ann Thorac Surg 14:243-259, 1972 7 Bartlett RH, Gazzaniga AB: Physiology and pathophysiology of extracorporeal circulation, Current Techniques in Extracorporeal Circulation, MI Ionescu, GH Wooler, eds., London, 1976, Butterworth & Co., Ltd., pp 1-44 8 May AG, DeWeese JA, Rob CG: Hemodynamic effects of arterial stenosis, Surgery 53:513-524, 1963 9 Berguer R, Hwang NC: Critical arterial stenosis. A theoretical and experimental solution. Ann Surg 180:3950, 1974 10 Bernhard JM, Johnson WD, Peterson 11: Carotid artery stenosis. Association with surgery for coronary artery disease. Arch Surg 105:837-840, 1972 11 Urschel HC, Razzuk MA, Gardner MA: Management of concomitant occlusive disease of the carotid and coronary arteries. J THORAC CARDIOVASC SURG 72:829-834, 1976
12 Mehigan JT, Buch WS, Pipkin RD, Fogarty TJ: A planned approach to coexistent cerebrovascular disease in coronary artery bypass candidates. Arch Surg 112: 14031409, 1977 13 Hertzer NR, Loop FD, Taylor PC, Beven EG: Staged and combined surgical approach to simultaneous carotid and coronary vascular disease. Surgery 84:803-811,1978 14 Carey JS, Cukingnan RA: Complications of combined brachiocephalic and coronary revascularization. Ann Thorac Surg 25:385, 1978 15 Morris GC, Ennix CL Jr, Lawrie GM, Crawford ES, Howell JF: Management of coexistent carotid and coronary artery occlusive atherosclerosis. Cleve Clin Q 45:125-127, 1977 16 Okies JE, Macmanus Q, Starr A: Myocardial revascularization and carotid endarterectomy. A combined approach. Ann Thorac Surg 23:561-564, 1977