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Internal Carotid Artery Pseudoaneurysm Related to Pregnancy
Internal Carotid Artery Pseudoaneurysm Related to Pregnancy Randy J. Irwin, MD, and M. Alex Jacocks, MD, Oklahoma City, Oklahoma
Arterial rupture is a common cause of maternal death. The increased tendency of true and false aneurysms to develop or rupture with advancing gestational age suggests that hemodynamic, hormonal, or other physiologic changes of pregnancy may play a role in their formation. To our knowledge, pseudoaneurysm formation from a carotid dissection or a ruptured true aneurysm related to pregnancy has not been previously reported. We report the successful repair of a large extracranial internal carotid artery pseudoaneurysm related to pregnancy. The clinical presentation, diagnostic modalities, surgical exposure, and treatment options for high internal carotid artery aneurysms will be discussed. (Ann Vasc Surg 2000;14:405-409.) DOI: 10.1007/s100169910073
True and false aneurysms of the extracranial carotid arteries are uncommon. Moreau et al. reported 8 aneurysms in 2000 operations of the internal carotid artery.1 McCollum et al. found 37 carotid aneurysms in 6500 carotid operations over a 21-year period.2 Most true aneurysms of the carotid arteries are due to atherosclerotic degeneration. Although true aneurysms and arterial dissections are more common during pregnancy because of hormonal and hemodynamic changes, they have never been described of the carotid artery. This case report documents the diagnosis, pathologic changes, and treatment of a large internal carotid artery pseudoaneurysm related to pregnancy.
CASE REPORT A 35-year-old white woman (gravida 1, para 1) in excellent health with no antecedent history of trauma or infections complained of acute onset of a painful mass that
From the Department of Surgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK. Presented at the Fifty-first Annual Meeting of the Southwestern Surgical Congress, Coronado, CA, April 18-21, 1999. Correspondence to: M.A. Jacocks, MD, Department of Surgery, P.O. Box 26901, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73190, USA.
appeared at 40 weeks gestation on the right side of her neck just below the angle of the mandible. The mass progressively enlarged over the subsequent 6 months and was associated with mild difficulty swallowing food. She denied ischemic cerebrovascular symptoms. Her past history was only significant for hypertension during pregnancy that was diet controlled. She was a nonsmoker. She was a thin female with normal vital signs. Physical exam revealed an egg-sized, 5 × 4 cm pulsatile neck mass just below the angle of the right mandible, as seen in Figure 1. Intraorally, the mass protruded into the tonsillar fossa. A bruit was present over the right carotid artery. The remainder of her physical exam was unremarkable. Carotid duplex ultrasound and angiography revealed a 5 × 4 × 4 cm aneurysmal formation arising off the distal extracranial internal carotid artery as seen in Figures 2 and 3. The anterior and posterior communicating arteries were patent. After arteriography, test occlusion of the right internal carotid artery was performed using a Hunter balloon occluder system for 20 min without neurologic sequellae. Because of the high risk of cerebral vascular accidents, symptoms of dysphagia, and recent expansion, the pseudoaneurysm was resected. Under Lifescan electroencephalographic (Neurometrics) monitoring, the patient underwent general nasotracheal intubation and subluxation of the mandible. The pseudoaneurysm was approached through a standard presternomastoid incision. Access of the high internal carotid artery was achieved by anterior subluxation of the mandible, division of the di405
406
Case reports
Annals of Vascular Surgery
Her postoperative course was essentially unremarkable except for a right peripheral facial nerve neuropraxia and absent elevation of the soft palate with deviation of the uvula to the left. Both findings completely resolved within 3 months.
DISCUSSION
Fig. 1. Photograph showing the position and size of the mass in the right neck.
gastric and styloid muscles, reflection of the sternomastoid muscle off the mastoid process, and removal of the styloid process as seen in Figure 4. On the basis of results from the arterial balloon occlusion test and electroencephagraphic monitoring, a shunt was not used. After systemic heparinization (100 units/kg B.W.), the pseudoaneurysm was opened, revealing no evidence of atherosclerosis, but a 4 × 4 × 2-cm well-organized thrombus within the pseudoaneurysm was seen (Fig. 5). The pseudoaneurysm was resected. Arterial continuity was restored using a transposed proximal greater saphenous vein graft, anastomosed end to end with a running 6/0 polypropylene suture. Gross exam revealed a large aneurysm formation distal to the hypoglossal nerve, probably arising from an arterial dissection or rupture of a true aneurysm. Microscopic exam showed fragmentation of the internal elastic lamella, loss of normal corrugation of elastic fibers, and diffuse increased proteoglycan deposition that is consistent with cystic medial necrosis, as seen in Figure 6. The aneurysmal formation appeared to be a pseudoaneurysm because the lining did not contain intima, media, or adventitia. No evidence of dissection was present on histologic or gross exams.
Arterial rupture is a common cause of maternal death.3 The increased tendency of an aneurysm to develop or rupture with advancing gestational age and in multiparous women suggest that hemodynamic, hormonal, or other physiologic changes of pregnancy may play a role in aneurysm formation. Many authors have reported true aneurysms during pregnancy that involve the splenic, aortic, renal, and cerebral vessels4 Arterial dissection of the aorta, coronary, and iliac arteries have been related to pregnancy.4 A pseudoaneurysm arising from rupture of a true aneurysm or arterial dissection has never been described. Most authors believe the cause of true aneurysms and arterial dissection during pregnancy is multifactorial. Histopathologic changes in the arterial wall closely mimic cystic medial necrosis. In a comparison of aortic wall histologies in pregnant and nonpregnant women, Manallo-Estrella and Barker found that the arterial wall in pregnant women developed smooth muscle hyperplasia, fragmentation of the internal elastic lamella, and loss of normal elastic fiber alignment as was seen in our patient.5 Some authors report an increase in acid mucopolysaccharides, as seen in this patient, whereas others report a decreased amount.4 Animal experiments in pregnant rabbits and rats have shown increased degeneration of the arterial wall throughout pregnancy and with repeated pregnancies, without repair.6,7 These histologic changes result in a weakened arterial wall. The hemodynamic changes during pregnancy include increased heart rate, stroke volume, cardiac output, and aortic size. Rutherford and Nolte believe the gravid uterus compresses the abdominal aorta, causing further increase in blood flow and pressure in the upper aorta.4 The hemodynamic changes during pregnancy cause increased stress on the arterial wall. The hemodynamic changes during pregnancy in addition to the hormonal weakening of the arterial wall at times lead to aneurysm formation, dissection, and even rupture. Because of a 30-75% risk of stroke from emboli of a thrombus within the aneurysm if left untreated, aggressive surgical intervention is recommended.8,9 Sir Astley Cooper ligated a carotid artery aneurysm in 1808. Ligation has been associ-
Vol. 14, No. 4, 2000
Case reports 407
Fig. 2. Selected anteroposterior right carotid arteriogram showing a large distal internal carotid aneurysmal formation. Fig. 3. Selected lateral right carotid arteriogram showing a large distal internal carotid aneurysmal formation.
Fig. 4. Intraoperative photograph showing the carotid pseudoaneurysm in relation to the hypoglossal nerve.
408
Case reports
Annals of Vascular Surgery
Fig. 5. Intraoperative photograph showing irregular thrombus within the pseudoaneurysm.
Fig. 6. Histological section showing cystic medial necrosis within the carotid artery and no endothelial lining within the pseudoaneurysm. Elastic Van Gieson stain (original magnification, ×250).
ated with a 40% risk of stroke and is only used in the most dire of circumstances, such as aneurysms that extend into the intrapetrous portion of the internal carotid artery.1,10 Complex otologic techniques using a transmastoid approach to obtain distal internal carotid artery control have been described to avoid ligation even in these extreme cases.11 When carotid artery ligation is unavoidable
and cerebral ischemia is likely, an extraintracranial bypass can prevent neurologic sequellae.12 Currently, three modes of treatment are most widely used, depending on size, extent, and type of aneurysm. Some saccular aneurysms can be treated by excision and patching of the artery or endoaneurysmorrhaphy.13 Small aneurysms can often be resected with primary anastomosis. For proximal internal carotid aneurysms, the external carotid artery can be sacrificed with anastomosis of the proximal external carotid artery to the distal internal carotid artery. However, for large aneurysms or aneurysms involving the distal internal carotid artery, the aneurysm should be resected and arterial continuity reestablished with greater saphenous vein, because of the high incidence of a stroke with ligation. Recently, endovascular techniques to exclude the internal carotid artery aneurysm by stenting or thrombosis of the aneurysm with platinum coils and silicone balloons have been attempted but remain unproven.14 There are several reports of true aneurysms and arterial dissection during pregnancy, but none involve the carotid artery. This case report documents a spontaneous pseudoaneurysm during pregnancy of the extracranial internal carotid artery. It also confirms the histologic arterial wall changes seen during pregnancy consistent with cystic medial necrosis. Large distal internal carotid true and false aneurysms can be repaired using simple modern vascular surgical techniques, with minimal morbidity.
Vol. 14, No. 4, 2000
REFERENCES 1. Moreau P, Albat B, Thevenet A. Surgical treatment’s of extracranial internal carotid artery aneurysms. Ann Vasc Surg 1994;8:409-416. 2. McCollum CH, Wheeler WG, Noon GP, et al. Aneurysms of extracranial carotid artery: twenty-one years experience. Am J Surg 1979;137:196-200. 3. Williams GM, Gott VL, Brawley RK, et al. Aortic disease associated with pregnancy. J Vasc Surg 1988;8:470-475. 4. Rutherford RB, Nolte JE. Aortic and other dissections associated with pregnancy. Semin Vasc Surg 1995;8:299-305. 5. Manallo-Estrella P, Barker AE. Histopathologic findings in human aortic media associated with pregnancy. Arch Pathol 1967;83:336-341. 6. Wexler BC. Vascular degenerative changes in the uterine arteries and veins of multiparous rats. Am J Obstet Gynecol 1970;107:6-16. 7. Manallo-Estrella P, Danforth DN, Buckingham JC, et al. Regression rate of vascular effects induced by pregnancy and by norethynodrel-mestranol. Fertil Steril 1965;16:81-84. 8. Margolis MT, Stein RL, Newton TH. Aneurysms of the internal carotid artery. Neuroradiology 1972;4:78-89.
Case reports 409
9. Zwolak RM, Whitehouse WM, Knake JE, et al. Atherosclerotic extracranial carotid artery aneurysms. J Vasc Surg 1984;1:415-422. 10. Basattil RW, Davidson RK, Foley KT, et al. Selective management of extracranial carotid arterial aneurysms. Am J Surg 1980;140:85-91. 11. Purdue GF, Pelligrini RV, Arena S. Aneurysms of the high internal carotid artery: a new approach. Surgery 1981;89: 268-270. 12. Smith PG, Bond AG, Whitaker SR, et al. Management of aneurysms of the petrous portion of the internal carotid artery by resection and primary anastomosis. Laryngoscope 1983;93:1445-1453. 13. Matas R. Further experiences in the radical operations of the cure of aneurysm by the author’s method of intrasaccular suture (endo-aneurismorrhaphy). Trans Am Surg Assoc 1905;23:323-388. 14. Higashida RT, Hieshima GB, Halbach VV, et al. Cervical carotid artery aneurysms and pseudoaneurysms: treatment by balloon embolization therapy. Acta Radiol Suppl 1986;369: 591-593.
Arterial rupture is a common cause of maternal death. The increased tendency of true and false aneurysms to develop or rupture with advancing gestational age suggests that hemodynamic, hormonal, or other physiologic changes of pregnancy may play a role in their formation. To our knowledge, pseudoaneurysm formation from a carotid dissection or a ruptured true aneurysm related to pregnancy has not been previously reported. We report the successful repair of a large extracranial internal carotid artery pseudoaneurysm related to pregnancy. The clinical presentation, diagnostic modalities, surgical exposure, and treatment options for high internal carotid artery aneurysms will be discussed. (Ann Vasc Surg 2000;14:405-409.) DOI: 10.1007/s100169910073
True and false aneurysms of the extracranial carotid arteries are uncommon. Moreau et al. reported 8 aneurysms in 2000 operations of the internal carotid artery.1 McCollum et al. found 37 carotid aneurysms in 6500 carotid operations over a 21-year period.2 Most true aneurysms of the carotid arteries are due to atherosclerotic degeneration. Although true aneurysms and arterial dissections are more common during pregnancy because of hormonal and hemodynamic changes, they have never been described of the carotid artery. This case report documents the diagnosis, pathologic changes, and treatment of a large internal carotid artery pseudoaneurysm related to pregnancy.
CASE REPORT A 35-year-old white woman (gravida 1, para 1) in excellent health with no antecedent history of trauma or infections complained of acute onset of a painful mass that
From the Department of Surgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK. Presented at the Fifty-first Annual Meeting of the Southwestern Surgical Congress, Coronado, CA, April 18-21, 1999. Correspondence to: M.A. Jacocks, MD, Department of Surgery, P.O. Box 26901, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73190, USA.
appeared at 40 weeks gestation on the right side of her neck just below the angle of the mandible. The mass progressively enlarged over the subsequent 6 months and was associated with mild difficulty swallowing food. She denied ischemic cerebrovascular symptoms. Her past history was only significant for hypertension during pregnancy that was diet controlled. She was a nonsmoker. She was a thin female with normal vital signs. Physical exam revealed an egg-sized, 5 × 4 cm pulsatile neck mass just below the angle of the right mandible, as seen in Figure 1. Intraorally, the mass protruded into the tonsillar fossa. A bruit was present over the right carotid artery. The remainder of her physical exam was unremarkable. Carotid duplex ultrasound and angiography revealed a 5 × 4 × 4 cm aneurysmal formation arising off the distal extracranial internal carotid artery as seen in Figures 2 and 3. The anterior and posterior communicating arteries were patent. After arteriography, test occlusion of the right internal carotid artery was performed using a Hunter balloon occluder system for 20 min without neurologic sequellae. Because of the high risk of cerebral vascular accidents, symptoms of dysphagia, and recent expansion, the pseudoaneurysm was resected. Under Lifescan electroencephalographic (Neurometrics) monitoring, the patient underwent general nasotracheal intubation and subluxation of the mandible. The pseudoaneurysm was approached through a standard presternomastoid incision. Access of the high internal carotid artery was achieved by anterior subluxation of the mandible, division of the di405
406
Case reports
Annals of Vascular Surgery
Her postoperative course was essentially unremarkable except for a right peripheral facial nerve neuropraxia and absent elevation of the soft palate with deviation of the uvula to the left. Both findings completely resolved within 3 months.
DISCUSSION
Fig. 1. Photograph showing the position and size of the mass in the right neck.
gastric and styloid muscles, reflection of the sternomastoid muscle off the mastoid process, and removal of the styloid process as seen in Figure 4. On the basis of results from the arterial balloon occlusion test and electroencephagraphic monitoring, a shunt was not used. After systemic heparinization (100 units/kg B.W.), the pseudoaneurysm was opened, revealing no evidence of atherosclerosis, but a 4 × 4 × 2-cm well-organized thrombus within the pseudoaneurysm was seen (Fig. 5). The pseudoaneurysm was resected. Arterial continuity was restored using a transposed proximal greater saphenous vein graft, anastomosed end to end with a running 6/0 polypropylene suture. Gross exam revealed a large aneurysm formation distal to the hypoglossal nerve, probably arising from an arterial dissection or rupture of a true aneurysm. Microscopic exam showed fragmentation of the internal elastic lamella, loss of normal corrugation of elastic fibers, and diffuse increased proteoglycan deposition that is consistent with cystic medial necrosis, as seen in Figure 6. The aneurysmal formation appeared to be a pseudoaneurysm because the lining did not contain intima, media, or adventitia. No evidence of dissection was present on histologic or gross exams.
Arterial rupture is a common cause of maternal death.3 The increased tendency of an aneurysm to develop or rupture with advancing gestational age and in multiparous women suggest that hemodynamic, hormonal, or other physiologic changes of pregnancy may play a role in aneurysm formation. Many authors have reported true aneurysms during pregnancy that involve the splenic, aortic, renal, and cerebral vessels4 Arterial dissection of the aorta, coronary, and iliac arteries have been related to pregnancy.4 A pseudoaneurysm arising from rupture of a true aneurysm or arterial dissection has never been described. Most authors believe the cause of true aneurysms and arterial dissection during pregnancy is multifactorial. Histopathologic changes in the arterial wall closely mimic cystic medial necrosis. In a comparison of aortic wall histologies in pregnant and nonpregnant women, Manallo-Estrella and Barker found that the arterial wall in pregnant women developed smooth muscle hyperplasia, fragmentation of the internal elastic lamella, and loss of normal elastic fiber alignment as was seen in our patient.5 Some authors report an increase in acid mucopolysaccharides, as seen in this patient, whereas others report a decreased amount.4 Animal experiments in pregnant rabbits and rats have shown increased degeneration of the arterial wall throughout pregnancy and with repeated pregnancies, without repair.6,7 These histologic changes result in a weakened arterial wall. The hemodynamic changes during pregnancy include increased heart rate, stroke volume, cardiac output, and aortic size. Rutherford and Nolte believe the gravid uterus compresses the abdominal aorta, causing further increase in blood flow and pressure in the upper aorta.4 The hemodynamic changes during pregnancy cause increased stress on the arterial wall. The hemodynamic changes during pregnancy in addition to the hormonal weakening of the arterial wall at times lead to aneurysm formation, dissection, and even rupture. Because of a 30-75% risk of stroke from emboli of a thrombus within the aneurysm if left untreated, aggressive surgical intervention is recommended.8,9 Sir Astley Cooper ligated a carotid artery aneurysm in 1808. Ligation has been associ-
Vol. 14, No. 4, 2000
Case reports 407
Fig. 2. Selected anteroposterior right carotid arteriogram showing a large distal internal carotid aneurysmal formation. Fig. 3. Selected lateral right carotid arteriogram showing a large distal internal carotid aneurysmal formation.
Fig. 4. Intraoperative photograph showing the carotid pseudoaneurysm in relation to the hypoglossal nerve.
408
Case reports
Annals of Vascular Surgery
Fig. 5. Intraoperative photograph showing irregular thrombus within the pseudoaneurysm.
Fig. 6. Histological section showing cystic medial necrosis within the carotid artery and no endothelial lining within the pseudoaneurysm. Elastic Van Gieson stain (original magnification, ×250).
ated with a 40% risk of stroke and is only used in the most dire of circumstances, such as aneurysms that extend into the intrapetrous portion of the internal carotid artery.1,10 Complex otologic techniques using a transmastoid approach to obtain distal internal carotid artery control have been described to avoid ligation even in these extreme cases.11 When carotid artery ligation is unavoidable
and cerebral ischemia is likely, an extraintracranial bypass can prevent neurologic sequellae.12 Currently, three modes of treatment are most widely used, depending on size, extent, and type of aneurysm. Some saccular aneurysms can be treated by excision and patching of the artery or endoaneurysmorrhaphy.13 Small aneurysms can often be resected with primary anastomosis. For proximal internal carotid aneurysms, the external carotid artery can be sacrificed with anastomosis of the proximal external carotid artery to the distal internal carotid artery. However, for large aneurysms or aneurysms involving the distal internal carotid artery, the aneurysm should be resected and arterial continuity reestablished with greater saphenous vein, because of the high incidence of a stroke with ligation. Recently, endovascular techniques to exclude the internal carotid artery aneurysm by stenting or thrombosis of the aneurysm with platinum coils and silicone balloons have been attempted but remain unproven.14 There are several reports of true aneurysms and arterial dissection during pregnancy, but none involve the carotid artery. This case report documents a spontaneous pseudoaneurysm during pregnancy of the extracranial internal carotid artery. It also confirms the histologic arterial wall changes seen during pregnancy consistent with cystic medial necrosis. Large distal internal carotid true and false aneurysms can be repaired using simple modern vascular surgical techniques, with minimal morbidity.
Vol. 14, No. 4, 2000
REFERENCES 1. Moreau P, Albat B, Thevenet A. Surgical treatment’s of extracranial internal carotid artery aneurysms. Ann Vasc Surg 1994;8:409-416. 2. McCollum CH, Wheeler WG, Noon GP, et al. Aneurysms of extracranial carotid artery: twenty-one years experience. Am J Surg 1979;137:196-200. 3. Williams GM, Gott VL, Brawley RK, et al. Aortic disease associated with pregnancy. J Vasc Surg 1988;8:470-475. 4. Rutherford RB, Nolte JE. Aortic and other dissections associated with pregnancy. Semin Vasc Surg 1995;8:299-305. 5. Manallo-Estrella P, Barker AE. Histopathologic findings in human aortic media associated with pregnancy. Arch Pathol 1967;83:336-341. 6. Wexler BC. Vascular degenerative changes in the uterine arteries and veins of multiparous rats. Am J Obstet Gynecol 1970;107:6-16. 7. Manallo-Estrella P, Danforth DN, Buckingham JC, et al. Regression rate of vascular effects induced by pregnancy and by norethynodrel-mestranol. Fertil Steril 1965;16:81-84. 8. Margolis MT, Stein RL, Newton TH. Aneurysms of the internal carotid artery. Neuroradiology 1972;4:78-89.
Case reports 409
9. Zwolak RM, Whitehouse WM, Knake JE, et al. Atherosclerotic extracranial carotid artery aneurysms. J Vasc Surg 1984;1:415-422. 10. Basattil RW, Davidson RK, Foley KT, et al. Selective management of extracranial carotid arterial aneurysms. Am J Surg 1980;140:85-91. 11. Purdue GF, Pelligrini RV, Arena S. Aneurysms of the high internal carotid artery: a new approach. Surgery 1981;89: 268-270. 12. Smith PG, Bond AG, Whitaker SR, et al. Management of aneurysms of the petrous portion of the internal carotid artery by resection and primary anastomosis. Laryngoscope 1983;93:1445-1453. 13. Matas R. Further experiences in the radical operations of the cure of aneurysm by the author’s method of intrasaccular suture (endo-aneurismorrhaphy). Trans Am Surg Assoc 1905;23:323-388. 14. Higashida RT, Hieshima GB, Halbach VV, et al. Cervical carotid artery aneurysms and pseudoaneurysms: treatment by balloon embolization therapy. Acta Radiol Suppl 1986;369: 591-593.