Free-floating Thrombus of the Extracranial Internal Carotid Artery Joel Combe", MD, Philippe Poinsard, MD*, Jacques Besancenot, MD,* Gabriel Camelot*, MD, Franqoise Cattin**, MD, Jean-Franqois Bonneville, MD**, Thierry Moulin, MD, Jean-Louis Henlin, MD, Jean-Luc Chopard, MD, Louis Cotte, MD, Besangon, France
Free-floating clots of the extracranial internal carotid artery are generally considered as surgical emergencies. This retrospective study analyzes six free-floating clots diagnosed by arteriography. Three of these patients had a fixed stroke while the other three had an evolving stroke. Three patients had antecedent ocular or hemispheric transient ischemic attacks. The causes of free-floating clots in the internal carotid artery were atheromatous stenosis in two cases, ulcerated plaque in three cases, and carotid artery dissection in one. All six patients were seen late, approximately 15 hours after their neurologic accident. They were treated with intravenous heparin over a two to five week period. Repeat arteriograms demonstrated complete clot lysis in four instances, while partial lysis was seen in one case. Moderate extension of thrombus occurred in one case only. No further neurologic complications were noted during the treatment by heparin. As indicated by follow-up arteriographic findings, secondary surgery was performed for major carotid lesions and residual clots in five cases. The free-floating thrombus syndrome of the carotid artery should not be considered as a surgical emergency when discovered late in the wake of an acute neurologic accident. (Ann Vasc Surg 1990;4:558-562). KEY WORDS: cident.
Free-floating thrombus; internal carotid artery; cerebrovascular ac-
Free-floating blood clots in the extracranial internal carotid artery (ICA) are often operated on in an emergency setting [ I ,2]. Recently, thrombolysis has also been proposed [ 3 ] . The goal of this retrospective study was to assess the results of a therapeutic scheme based on heparin therapy in the acute phase From the Services de Chirurgie Vascirluire*, Neirrorudidogie et Neurologic**, C.H.U Jean Minjoz, 25000 Besungon, France. Presented at the Annuul Meeting of the S o c i k t k de Chirurgie Vusculuire de Langue FrunquiAe, JunP 23-24, 1989, Strasbourg, France. Reprint requests: Joel Cornhe, MD, Service de Chirirrgie Vasculaire, C.H. U Jeun Minjoz, 25000 Besungon, France.
of the neurologic event followed by secondary elective surgery.
PATIENTS Six consecutive cases of free-floating thrombus in the extracranial portion of the ICA were diagnosed by arteriography between January 1, 1981, and December I , 1988, at Jean Minjoz University Hospital Center in Besanqon, France. Diagnosis of free-floating thrombus was considered when a filling defect was found in the proximal ICA on biplane arteriograms [4]. To be included for this study, the defect had to be regular, pedicled, and nonocclusive, and measure at least 10 mm in length. Patients 558
VOLUME 4 N o 6 - 1990
CAR07’11) THROMBUS
with minimal mural clots discovered on arteriograms or intraoperatively, as well as patients with complete carotid artery occlusions and embolisms of cardiac origin were eliminated from this study. The exact incidence of these excluded cases is not known. The mean age of patients was 59 years. There were four men and two women. Five patients were hypertensive, whereas none had either recognized lower limb arterial disease or coronary artery disease. Three patients had recent antecedent transient ischemic attacks (TIA) which were ocular in three cases, and hemispheric in one. All six patients had been admitted for ipsilateral neurologic accidents with fixed (three cases) or crescendo (three cases) strokes. All patients were seen late, at a mean of 15 hour$ after the onset of their neurologic event. The initial neurologic accident was a hemispheric deficit in five cases (two patients with hemiplegia and aphasia, two with brachiofacial paresis, one with isolated aphasia) and an ocular accident in one case. Pulsed Doppler, combined pulsed Doppler, and B mode sonography demonstrated hemodynamic abnormalities in all six cases and led to the disclosure of carotid stenosis in two cases. In one instance only, a free-floating thrombus was suspected by these investigative procedures. Cerebral computerized tomography (CT) scans were obtained in all six cases. Focal hypodensities were found in three patients (enhancement was obtained in one case only) upon admission. CT scan signs were delayed in two cases (day 3 and day 7) without aggravation or new neurologic events. Arteriograms of the symptomatic carotid artery were obtained through the femoral route by retrograde catheterization. Transient aggravation of neurologic status was noted in one case after arteriographic investigation. Five of the free-floating clots measured 15 mm or more, and three extended to the ICA behind the styloid process. In two cases, distal cerebral artery occlusion thought to be due to embolism was encountered. Contralateral asymptomatic carotid atheroma were identified in two cases. Of six carotid emergency arteriograms, only two revealed that the free-floating thrombus was associated with very tight stenosis. All six patients had continuous intravenous heparin, 3 to 4 mg/kg body weighti24 hours, administered by an electric infusion pump during two to five weeks. Therapy was considered efficacious when activated cephalin times obtained were at two to three times the control values. Follow-up arteriograms were obtained twice in four patients, once in one patient and three times in the patient in whom the free-floating clot revealed carotid artery dissection. After obtaining clot lysis, repeat arteriograms showed three ulcerated plaques and one carotid artery dissection, confirmed by cervical CT scan.
Fig. 1. Left carotid artery arteriograms upon admission: free-floating clot and tight stenosis of carotid artery.
Elective surgery was delayed in five of six patients. In one case, thromboendarterectomy was performed 15 days later for an extensive clot developed on an ulcerated carotid plaque. Four endarterectomies were performed without angioplasty or temporary shunt 30 to 40 days later. These included one operation for residual clot on ulcerated plaque, two tight stenoses without residual clot and one ulcerated plaque without residual clot. RESULTS None of the six patients treated by heparin experienced further neurologic accidents. Initial neurologic disorders improved in all cases. Repeat arteriograms and intraoperative findings showed that lysis of carotid thrombus was complete in four cases between 25 and 38 days after commencement of treatment with heparin (Figs. 1, 2). Moderate extension of clot was noted at 15 days in one patient who was receiving inadequate anticoagulation. This patient had a residual clot 37 days after adequate heparin therapy.
560
CAROTID THROMBUS
A N N A L S OF
VASCULAR SURGERY
dressed herein is the value of initial and secondary etiologic and general evaluations which determine the choice between interval surgery and medical treatment only. Free-floating clots in the extracranial ICA, first described by Ehrenfeld in 1966, have prompted few specific studies [4,5,8-11]. A total of 112 cases, including some in series which studied acute carotid artery ischemia in general [2,3], have been documented to date. The incidence of free-floating clots discovered on arteriograms of the carotid artery ranges between 0.7% [S] and 2.9%, all sizes included [ S ] . Roentgenologic diagnosis of such clots is difficult. Of 16 patients in the series of Buchan and associates [ 5 ] operated on under emergency conditions, all had an intraluminal clot. As expected, two had an intracranial thrombus, but three clots, thought to be located in the cervical carotid artery, were not found by the surgeon. Misleading images distal to carotid stenosis have been encountered frequently with traditional and venous digital arteriography techniques. To avoid these errors, Hugh [6] proposed to slowly inject highly concentrated quantities of contrast medium (trickle arteriography) at very short range from the carotid bifurcation. The principal risk of false positive diagnosis concerns small clots, which were excluded from our series. Conversely, long extracranial intraluminal clots can simulate carotid occlusion [ 7 ]and require Fig. 2. Left carotid follow-up arteriogram 17 days late films for correct diagnosis. Digital arteriograafter initiation of treatment (same patient as in Fig. 1): phy performed by retrograde femoral artery cathecomplete lysis of free-floating clot. terization including the catheterization of the pathologic carotid artery, whenever feasible, is the investigation of choice. Anteroposterior and lateral In five patients undergoing secondary carotid serial views are mandatory [4]. Progressive regression of thrombus on successive surgery, there were no postoperative neurologic accidents. At follow-up (13 months to 109 months), arteriograms was decisive for diagnosis in our setwo patients had complete neurologic recovery, two ries. In two cases of residual or extensive thromhad minimal residual deficits (discrete speech dis- bus, the clot was found at operation. In the three orders) and two had mild-to-moderate residual dis- cases in which complete radiologic lysis had been orders (one patient with monoparesia and one pa- achieved. no gross or microscopic thrombus was tient with ipsilateral visual deficit). At the end of observed. Patients have an increased risk of neurologic treatment, follow-up pulsed Doppler and sonography showed no hemodynamic or morphologic ab- aggravation after selective arteriography during the acute phase of stroke [2,4]. Before institution of normalities in all of the operated carotid arteries. In the patient with dissection who did not un- heparin therapy, a long carotid clot is unstable, dergo surgery, pulsed sonography Doppler and ar- potentially emboligenic, and, whenever suspected teriograms showed that the internal carotid was by sonography, should prompt delayed initial arteriography . Repeated arteriography sessions carry a patent at four months. small neurologic risk in the chronic phase. FoIlow-up arteriography is recommended three weeks after commencement of heparin therapy. DISCUSSION Donnan and Bladin [8] spoke of the “stroke The results in this series underscore the clinical syndrome of long intraluminal clot with incomplete and roentgenologic effectiveness of heparin therapy vessel obstruction”, attesting to the stereotyped in the acute phase of treatment of neurologic acci- clinical and arteriographic aspect of such clots. Of dents associated with free-floating clots in the ex- 112 documented cases [2-121, 102 patients were tracranial ICA. Another issue of importance ad- admitted for acute stroke. Only 10 patients were
VOLUME 4 N o 6 - 1990
CAROTID THROMBUS
asymptomatic or seen after TIA [5-121. Tight stenosis of the proximal ICA was the predominant cause of intraluminal clots as reported by Caplan and colleagues [9], who found this etiology in five of nine cases, and Pelz and coworkers 141 and Buchan and associates I S ] , who found stenosis in 23 of 29 cases. In contrast, we encountered this etiology in only two of six cases. Large or small ulcerated plaques are the second most frequent cause (three cases in our series). Carotid artery dissection (one personal case) 151, lipidic ray [ 9 ] ,and unrecognized trauma are other known but rare causes. In the acute phase, etiologic diagnosis is easy only in the case of tight carotid artery stenosis. Intraluminal clots hinder the evaluation of carotid walls and correct diagnosis is often made only after arteriograms are obtained following thrombolysis. Minimal ulcerations are more often a factor of localization rather than an etiologic factor. In these particular circumstances, a rheologic factor, such as neoplasm, polycythemia 191 or collagen disease [lo] must be searched for. Therapeutic indications in acute cerebral ischemia are divided between those who advocate emergency surgical [2] or thrombolytic 131 revascularization and those who prefer to first treat medically and then perform secondary elective surgery [51. In the particular setting of intraluminal free-floating clots, details of outcome are not given for each method except in the series of Pelz and colleagues [4], updated by Buchan and coworkers in 1988 151. These authors compared the outcome of 14 patients who did not undergo emergency operation with that of 15 patients who were operated on within 27 hours on the average after onset of neurologic disorders. All patients had a free-floating clot in the extracranial ICA. The 14 patients without emergency surgery all had a favorable outcome. In eight cases, the carotid stenosis was thought to be minimal. Secondary surgery was performed in six cases with one postoperative neurologic event. Of the 15 patients undergoing emergency surgery, I 1 actually had a free-floating clot in the extracranial ICA encountered at operation. Four of these patients experienced a postoperative neurologic complication due to extension of the ischemic focus or new cerebral infarction. Goldstone [2] obtained better neurologic results with surgery in 55% of patients but reported a 45% failure rate, including 25% of patients with unchanged neurologic status, 10% of patients with aggravation of deficits and 10% patient deaths. Acute cerebral ischemia, however, varied in this series, and the specific outcome in the case of long free-floating clots of the extracranial ICA was not detailed. The expected advantages of emergency revascularization surgery are to limit areas of infarction by reducing the perilesional area of critical perfusion [3]. However, in the case of long free-
561
floating clot of the carotid artery, emergency surgery carries a high risk of neurologic complication. Iatrogenic embolism is always possible during dissection of the neck, especially in the acute phase when clots are extremely friable and are located in the distal portion of the extracranial ICA. The second risk is that of possible aggravation of cerebral ischemia due to carotid artery clamping. Neither rapid thrombectomy or temporary inlay shunt whose positioning is delicate are absolute guarantees. Moreover, restoration of carotid flow does not reverse all of the intracranial factors influencing outcome including perilesional edema, hypertensive bouts, intrafocal hemorrhage, persistent distal arterial occlusion or postembolic arterial disease. Modern revascularization methods are directed toward emergency local thrombolysis. Clinical and CT scan criteria for thrombolysis, however, as reported by Maiza and associates 131, are rarely met. None of our patients were seen early enough to allow us to attempt thrombolysis. Little is known about the outcome of local thrombolysis for extracranial carotid clots. Five cases were included in the series of 16 cases reported by Maiza and associates [3]. All patients had acute cerebral ischemia but details of outcome are not given. Overall results indicated that intra- and extracranial clots were consistently lysed. There were, however, two cases of iatrogenic cerebral embolism and one case of fatal frontal lobe hematoma. This method is promising as it achieves rapid lysis of clot, and allows for rapid secondary surgery. One possible drawback of the method is that it requires placing the catheter close to an unstable emboligenic lesion. The therapeutic schema used in our series was dictated by the fact that our patients were seen late when their stroke was already fixed or evolving. At this stage, in our opinion, caution should be exercised as to emergency revascularization surgery, whatever its type. The advantages of this medicosurgical approach in free-floating thrombus of the extracranial ICA are multiple. The principal advantage is to avoid surgery in a patient whose evaluation is incomplete and who is in a critical situation with combined acute cerebral ischemia, emboligenic clot and tight stenosis of the extracranial carotid artery. Another advantage is the possibility of elective and interval surgery. If diagnosis can be made earlier in the future, management of patients with free-floating thrombus of the carotid artery can be more aggressive. REFERENCES 1. WALTERS BB. OJEMANN RG, HEROS RC. Emergency
carotid endarterectomy. J Neurosurg 1987;66:817-823. 2. GOLDSTONE J . Emergency surgery for stroke in evolution and crescendo transient ischemic attacks. In: MOORE WS
562
3. 4.
5. 6.
7.
CAROTID THROMBUS
(ed). Surgery for Cerebrovascular Disease. New York 1987, Churchill Livingstone: 883-892. MAIZA D, THERON J , PELOUZE GA, et al. Local fibrinolytic therapy in ischemic carotid pathology. Ann Vnsc S U V 1988;2:205-2 ~ 14. PELZ DM, BUCHAN A, FOX AJ, et al. Intraluminal thrombus of the internal carotid arteries: angiographic demonstration of resolution with anticoagulant therapy alone. Rudiologv 1986;/60:369-373. BUCHAN A, GATES P, PELZ D, et al. Intraluminal thrombus in the cerebral Circulation: Implication for surgical management. Stroke 1988;19:681-687. HUGH AE. Trickle arteriography: demonstration of thrombi in the origin of the internal carotid artery. Brit Med J I97Q;2:574-576. GABRIELSEN TO. SEEGER JF. KNAKE JE, et al. The
8.
9. 10.
1I.
12.
ANNALS OF
VASCULARSUKGERY
nearly occluded internal carotid artery a diagnostic trap. Rudiology 1981:/38:611-618. DONNAN GA, BLADIN PF. The stroke syndrome of long intraluminal clot with incomplete vessel obstruction. Clin Exp Ne~irol1979:16:4147. CAPLAN L, STEIN, PATEL D, et al. lntraluminal clot of the carotid artery detected radiographically. Neurology 198434:1175-1181. BAKER WH, POTTHOFF WP, BILLER J , et al. Carotid artery thrombosis associated with lupus anticoagulant. Surgerv I985 ;98:612-615. HARRISSON MJG, MARSHALL J . The finding of thrombus at carotid endarterectomy and its relationship to the timing of surgery. Br J Surg 1977;64:511-512. ROBERSON GH, SCOTT WR, ROSENBAUM AE. Thrombi at the site of carotid stenosis: radiographic diagnosis. Rudiology 1973;109:353-356.
Free-floating clots of the extracranial internal carotid artery are generally considered as surgical emergencies. This retrospective study analyzes six free-floating clots diagnosed by arteriography. Three of these patients had a fixed stroke while the other three had an evolving stroke. Three patients had antecedent ocular or hemispheric transient ischemic attacks. The causes of free-floating clots in the internal carotid artery were atheromatous stenosis in two cases, ulcerated plaque in three cases, and carotid artery dissection in one. All six patients were seen late, approximately 15 hours after their neurologic accident. They were treated with intravenous heparin over a two to five week period. Repeat arteriograms demonstrated complete clot lysis in four instances, while partial lysis was seen in one case. Moderate extension of thrombus occurred in one case only. No further neurologic complications were noted during the treatment by heparin. As indicated by follow-up arteriographic findings, secondary surgery was performed for major carotid lesions and residual clots in five cases. The free-floating thrombus syndrome of the carotid artery should not be considered as a surgical emergency when discovered late in the wake of an acute neurologic accident. (Ann Vasc Surg 1990;4:558-562). KEY WORDS: cident.
Free-floating thrombus; internal carotid artery; cerebrovascular ac-
Free-floating blood clots in the extracranial internal carotid artery (ICA) are often operated on in an emergency setting [ I ,2]. Recently, thrombolysis has also been proposed [ 3 ] . The goal of this retrospective study was to assess the results of a therapeutic scheme based on heparin therapy in the acute phase From the Services de Chirurgie Vascirluire*, Neirrorudidogie et Neurologic**, C.H.U Jean Minjoz, 25000 Besungon, France. Presented at the Annuul Meeting of the S o c i k t k de Chirurgie Vusculuire de Langue FrunquiAe, JunP 23-24, 1989, Strasbourg, France. Reprint requests: Joel Cornhe, MD, Service de Chirirrgie Vasculaire, C.H. U Jeun Minjoz, 25000 Besungon, France.
of the neurologic event followed by secondary elective surgery.
PATIENTS Six consecutive cases of free-floating thrombus in the extracranial portion of the ICA were diagnosed by arteriography between January 1, 1981, and December I , 1988, at Jean Minjoz University Hospital Center in Besanqon, France. Diagnosis of free-floating thrombus was considered when a filling defect was found in the proximal ICA on biplane arteriograms [4]. To be included for this study, the defect had to be regular, pedicled, and nonocclusive, and measure at least 10 mm in length. Patients 558
VOLUME 4 N o 6 - 1990
CAR07’11) THROMBUS
with minimal mural clots discovered on arteriograms or intraoperatively, as well as patients with complete carotid artery occlusions and embolisms of cardiac origin were eliminated from this study. The exact incidence of these excluded cases is not known. The mean age of patients was 59 years. There were four men and two women. Five patients were hypertensive, whereas none had either recognized lower limb arterial disease or coronary artery disease. Three patients had recent antecedent transient ischemic attacks (TIA) which were ocular in three cases, and hemispheric in one. All six patients had been admitted for ipsilateral neurologic accidents with fixed (three cases) or crescendo (three cases) strokes. All patients were seen late, at a mean of 15 hour$ after the onset of their neurologic event. The initial neurologic accident was a hemispheric deficit in five cases (two patients with hemiplegia and aphasia, two with brachiofacial paresis, one with isolated aphasia) and an ocular accident in one case. Pulsed Doppler, combined pulsed Doppler, and B mode sonography demonstrated hemodynamic abnormalities in all six cases and led to the disclosure of carotid stenosis in two cases. In one instance only, a free-floating thrombus was suspected by these investigative procedures. Cerebral computerized tomography (CT) scans were obtained in all six cases. Focal hypodensities were found in three patients (enhancement was obtained in one case only) upon admission. CT scan signs were delayed in two cases (day 3 and day 7) without aggravation or new neurologic events. Arteriograms of the symptomatic carotid artery were obtained through the femoral route by retrograde catheterization. Transient aggravation of neurologic status was noted in one case after arteriographic investigation. Five of the free-floating clots measured 15 mm or more, and three extended to the ICA behind the styloid process. In two cases, distal cerebral artery occlusion thought to be due to embolism was encountered. Contralateral asymptomatic carotid atheroma were identified in two cases. Of six carotid emergency arteriograms, only two revealed that the free-floating thrombus was associated with very tight stenosis. All six patients had continuous intravenous heparin, 3 to 4 mg/kg body weighti24 hours, administered by an electric infusion pump during two to five weeks. Therapy was considered efficacious when activated cephalin times obtained were at two to three times the control values. Follow-up arteriograms were obtained twice in four patients, once in one patient and three times in the patient in whom the free-floating clot revealed carotid artery dissection. After obtaining clot lysis, repeat arteriograms showed three ulcerated plaques and one carotid artery dissection, confirmed by cervical CT scan.
Fig. 1. Left carotid artery arteriograms upon admission: free-floating clot and tight stenosis of carotid artery.
Elective surgery was delayed in five of six patients. In one case, thromboendarterectomy was performed 15 days later for an extensive clot developed on an ulcerated carotid plaque. Four endarterectomies were performed without angioplasty or temporary shunt 30 to 40 days later. These included one operation for residual clot on ulcerated plaque, two tight stenoses without residual clot and one ulcerated plaque without residual clot. RESULTS None of the six patients treated by heparin experienced further neurologic accidents. Initial neurologic disorders improved in all cases. Repeat arteriograms and intraoperative findings showed that lysis of carotid thrombus was complete in four cases between 25 and 38 days after commencement of treatment with heparin (Figs. 1, 2). Moderate extension of clot was noted at 15 days in one patient who was receiving inadequate anticoagulation. This patient had a residual clot 37 days after adequate heparin therapy.
560
CAROTID THROMBUS
A N N A L S OF
VASCULAR SURGERY
dressed herein is the value of initial and secondary etiologic and general evaluations which determine the choice between interval surgery and medical treatment only. Free-floating clots in the extracranial ICA, first described by Ehrenfeld in 1966, have prompted few specific studies [4,5,8-11]. A total of 112 cases, including some in series which studied acute carotid artery ischemia in general [2,3], have been documented to date. The incidence of free-floating clots discovered on arteriograms of the carotid artery ranges between 0.7% [S] and 2.9%, all sizes included [ S ] . Roentgenologic diagnosis of such clots is difficult. Of 16 patients in the series of Buchan and associates [ 5 ] operated on under emergency conditions, all had an intraluminal clot. As expected, two had an intracranial thrombus, but three clots, thought to be located in the cervical carotid artery, were not found by the surgeon. Misleading images distal to carotid stenosis have been encountered frequently with traditional and venous digital arteriography techniques. To avoid these errors, Hugh [6] proposed to slowly inject highly concentrated quantities of contrast medium (trickle arteriography) at very short range from the carotid bifurcation. The principal risk of false positive diagnosis concerns small clots, which were excluded from our series. Conversely, long extracranial intraluminal clots can simulate carotid occlusion [ 7 ]and require Fig. 2. Left carotid follow-up arteriogram 17 days late films for correct diagnosis. Digital arteriograafter initiation of treatment (same patient as in Fig. 1): phy performed by retrograde femoral artery cathecomplete lysis of free-floating clot. terization including the catheterization of the pathologic carotid artery, whenever feasible, is the investigation of choice. Anteroposterior and lateral In five patients undergoing secondary carotid serial views are mandatory [4]. Progressive regression of thrombus on successive surgery, there were no postoperative neurologic accidents. At follow-up (13 months to 109 months), arteriograms was decisive for diagnosis in our setwo patients had complete neurologic recovery, two ries. In two cases of residual or extensive thromhad minimal residual deficits (discrete speech dis- bus, the clot was found at operation. In the three orders) and two had mild-to-moderate residual dis- cases in which complete radiologic lysis had been orders (one patient with monoparesia and one pa- achieved. no gross or microscopic thrombus was tient with ipsilateral visual deficit). At the end of observed. Patients have an increased risk of neurologic treatment, follow-up pulsed Doppler and sonography showed no hemodynamic or morphologic ab- aggravation after selective arteriography during the acute phase of stroke [2,4]. Before institution of normalities in all of the operated carotid arteries. In the patient with dissection who did not un- heparin therapy, a long carotid clot is unstable, dergo surgery, pulsed sonography Doppler and ar- potentially emboligenic, and, whenever suspected teriograms showed that the internal carotid was by sonography, should prompt delayed initial arteriography . Repeated arteriography sessions carry a patent at four months. small neurologic risk in the chronic phase. FoIlow-up arteriography is recommended three weeks after commencement of heparin therapy. DISCUSSION Donnan and Bladin [8] spoke of the “stroke The results in this series underscore the clinical syndrome of long intraluminal clot with incomplete and roentgenologic effectiveness of heparin therapy vessel obstruction”, attesting to the stereotyped in the acute phase of treatment of neurologic acci- clinical and arteriographic aspect of such clots. Of dents associated with free-floating clots in the ex- 112 documented cases [2-121, 102 patients were tracranial ICA. Another issue of importance ad- admitted for acute stroke. Only 10 patients were
VOLUME 4 N o 6 - 1990
CAROTID THROMBUS
asymptomatic or seen after TIA [5-121. Tight stenosis of the proximal ICA was the predominant cause of intraluminal clots as reported by Caplan and colleagues [9], who found this etiology in five of nine cases, and Pelz and coworkers 141 and Buchan and associates I S ] , who found stenosis in 23 of 29 cases. In contrast, we encountered this etiology in only two of six cases. Large or small ulcerated plaques are the second most frequent cause (three cases in our series). Carotid artery dissection (one personal case) 151, lipidic ray [ 9 ] ,and unrecognized trauma are other known but rare causes. In the acute phase, etiologic diagnosis is easy only in the case of tight carotid artery stenosis. Intraluminal clots hinder the evaluation of carotid walls and correct diagnosis is often made only after arteriograms are obtained following thrombolysis. Minimal ulcerations are more often a factor of localization rather than an etiologic factor. In these particular circumstances, a rheologic factor, such as neoplasm, polycythemia 191 or collagen disease [lo] must be searched for. Therapeutic indications in acute cerebral ischemia are divided between those who advocate emergency surgical [2] or thrombolytic 131 revascularization and those who prefer to first treat medically and then perform secondary elective surgery [51. In the particular setting of intraluminal free-floating clots, details of outcome are not given for each method except in the series of Pelz and colleagues [4], updated by Buchan and coworkers in 1988 151. These authors compared the outcome of 14 patients who did not undergo emergency operation with that of 15 patients who were operated on within 27 hours on the average after onset of neurologic disorders. All patients had a free-floating clot in the extracranial ICA. The 14 patients without emergency surgery all had a favorable outcome. In eight cases, the carotid stenosis was thought to be minimal. Secondary surgery was performed in six cases with one postoperative neurologic event. Of the 15 patients undergoing emergency surgery, I 1 actually had a free-floating clot in the extracranial ICA encountered at operation. Four of these patients experienced a postoperative neurologic complication due to extension of the ischemic focus or new cerebral infarction. Goldstone [2] obtained better neurologic results with surgery in 55% of patients but reported a 45% failure rate, including 25% of patients with unchanged neurologic status, 10% of patients with aggravation of deficits and 10% patient deaths. Acute cerebral ischemia, however, varied in this series, and the specific outcome in the case of long free-floating clots of the extracranial ICA was not detailed. The expected advantages of emergency revascularization surgery are to limit areas of infarction by reducing the perilesional area of critical perfusion [3]. However, in the case of long free-
561
floating clot of the carotid artery, emergency surgery carries a high risk of neurologic complication. Iatrogenic embolism is always possible during dissection of the neck, especially in the acute phase when clots are extremely friable and are located in the distal portion of the extracranial ICA. The second risk is that of possible aggravation of cerebral ischemia due to carotid artery clamping. Neither rapid thrombectomy or temporary inlay shunt whose positioning is delicate are absolute guarantees. Moreover, restoration of carotid flow does not reverse all of the intracranial factors influencing outcome including perilesional edema, hypertensive bouts, intrafocal hemorrhage, persistent distal arterial occlusion or postembolic arterial disease. Modern revascularization methods are directed toward emergency local thrombolysis. Clinical and CT scan criteria for thrombolysis, however, as reported by Maiza and associates 131, are rarely met. None of our patients were seen early enough to allow us to attempt thrombolysis. Little is known about the outcome of local thrombolysis for extracranial carotid clots. Five cases were included in the series of 16 cases reported by Maiza and associates [3]. All patients had acute cerebral ischemia but details of outcome are not given. Overall results indicated that intra- and extracranial clots were consistently lysed. There were, however, two cases of iatrogenic cerebral embolism and one case of fatal frontal lobe hematoma. This method is promising as it achieves rapid lysis of clot, and allows for rapid secondary surgery. One possible drawback of the method is that it requires placing the catheter close to an unstable emboligenic lesion. The therapeutic schema used in our series was dictated by the fact that our patients were seen late when their stroke was already fixed or evolving. At this stage, in our opinion, caution should be exercised as to emergency revascularization surgery, whatever its type. The advantages of this medicosurgical approach in free-floating thrombus of the extracranial ICA are multiple. The principal advantage is to avoid surgery in a patient whose evaluation is incomplete and who is in a critical situation with combined acute cerebral ischemia, emboligenic clot and tight stenosis of the extracranial carotid artery. Another advantage is the possibility of elective and interval surgery. If diagnosis can be made earlier in the future, management of patients with free-floating thrombus of the carotid artery can be more aggressive. REFERENCES 1. WALTERS BB. OJEMANN RG, HEROS RC. Emergency
carotid endarterectomy. J Neurosurg 1987;66:817-823. 2. GOLDSTONE J . Emergency surgery for stroke in evolution and crescendo transient ischemic attacks. In: MOORE WS
562
3. 4.
5. 6.
7.
CAROTID THROMBUS
(ed). Surgery for Cerebrovascular Disease. New York 1987, Churchill Livingstone: 883-892. MAIZA D, THERON J , PELOUZE GA, et al. Local fibrinolytic therapy in ischemic carotid pathology. Ann Vnsc S U V 1988;2:205-2 ~ 14. PELZ DM, BUCHAN A, FOX AJ, et al. Intraluminal thrombus of the internal carotid arteries: angiographic demonstration of resolution with anticoagulant therapy alone. Rudiologv 1986;/60:369-373. BUCHAN A, GATES P, PELZ D, et al. Intraluminal thrombus in the cerebral Circulation: Implication for surgical management. Stroke 1988;19:681-687. HUGH AE. Trickle arteriography: demonstration of thrombi in the origin of the internal carotid artery. Brit Med J I97Q;2:574-576. GABRIELSEN TO. SEEGER JF. KNAKE JE, et al. The
8.
9. 10.
1I.
12.
ANNALS OF
VASCULARSUKGERY
nearly occluded internal carotid artery a diagnostic trap. Rudiology 1981:/38:611-618. DONNAN GA, BLADIN PF. The stroke syndrome of long intraluminal clot with incomplete vessel obstruction. Clin Exp Ne~irol1979:16:4147. CAPLAN L, STEIN, PATEL D, et al. lntraluminal clot of the carotid artery detected radiographically. Neurology 198434:1175-1181. BAKER WH, POTTHOFF WP, BILLER J , et al. Carotid artery thrombosis associated with lupus anticoagulant. Surgerv I985 ;98:612-615. HARRISSON MJG, MARSHALL J . The finding of thrombus at carotid endarterectomy and its relationship to the timing of surgery. Br J Surg 1977;64:511-512. ROBERSON GH, SCOTT WR, ROSENBAUM AE. Thrombi at the site of carotid stenosis: radiographic diagnosis. Rudiology 1973;109:353-356.
