Contralateral Carotid Artery Stenosis Research Articles

Pearls & Oy-sters: Resolution of hemichorea following endarterectomy for severe carotid stenosis

We report three patients with hemichorea who were found to have contralateral atherosclerotic carotid artery stenosis. Their details are compared in the table. All patients had carotid duplex ultrasonography because they exhibited neurologic signs or symptoms suggestive of cerebrovascular ischemia in addition to chorea. View this table: Table Characteristics of the three cases Patient A developed right hemichorea; 9 months later she experienced three episodes of right limb weakness and speech disorder lasting 5 minutes, suggestive of transient ischemia. The severity of chorea increased and it mildly affected the left side. Neurologic examination revealed predominantly right-sided chorea and mild orofacial dyskinesia without other neurologic signs. The following blood tests were normal: full blood count, inflammatory markers, coagulation studies, renal, glucose, bone, liver, and thyroid biochemistry, immunoglobulin electrophoresis, anticardiolipin antibodies, and antinuclear antibodies screen (including extractable nuclear antigens). CT of the head was normal. Carotid duplex ultrasonography revealed 90% stenosis in the left internal carotid artery. Patient B developed right hemichorea and 3 months later expressive dysphasia and right facial and hand weakness; this precipitated admission. In addition to chorea, there was right visual inattention and upper motor neuron weakness affecting the right face and hand with normal reflexes and plantar responses. The same blood tests as for patient A were normal; in addition, treponemal serology was consistent with past infection. MRI of the brain showed a left-sided parietal lobe infarct which was limited to the gray matter of the posterior parietal lobe suggestive …

The Probability of Restenosis, Contralateral Disease Progression, and Late Neurologic Events following Carotid Endarterectomy: A Long-Term Follow-Up Study

Background: Most studies that have reported on the progression of ipsilateral and/or contralateral internal carotid artery (ICA) stenosis are restricted to a few years. Methods: Based on a single-center carotid endarterectomy (CEA) registry, we sought all patients with CEA for symptomatic high-grade ICA stenosis between 1970 and 2002. 361 CEA patients (mean age 66 years, 73% male) with annual carotid ultrasound and clinical follow-up were identified. Kaplan-Meier analysis was used to estimate the occurrence of (i) progressive ICA stenosis or restenosis of either the operated or contralateral side, and (ii) cerebrovascular events over time of either the operated or contralateral side. Results: Progressive ICA disease was more likely on the contralateral than on the ipsilateral ICA (hazard ratio 2.71; CI 1.8–4.1, p < 0.001). After 5 years, the probability for progressive ICA disease was 5.2% for the ipsilateral versus 15.8% for the contralateral ICA. After 15 years, the likelihood was 37% for both sides. In the presence of progressive restenosis of the ipsilateral ICA, the 20-year probability of further ischemic cerebrovascular events was 50% compared to 18% in patients without ICA disease progression. For the contralateral ICA, the probability of further ischemic events was 24.5% in patients with ICA disease progression compared to 9.6% without ICA disease progression (15 years). Conclusion: 15 years after CEA, one third of the patients can be expected to develop progressive ICA disease. While ICA disease progression seems to be more prominent on the contralateral ICA within the first years, this difference fades out after 15 years. One out of 2 patients with ipsilateral ICA disease progression can be expected to have a recurrent cerebral ischemic event within 15 years. It remains to be determined whether consequent application of high-dose statins, optimal blood pressure management and antithrombotic therapy can reduce this rate.

Total Occlusion of the Common Carotid Artery: A Modified Classification and its Relation to Clinical Status

To investigate the hemodynamics and clinical presentation of common carotid artery occlusion (CCAO), we reviewed 6,415 patients with suspected carotid artery disease in whom a color Duplex imaging (CDI) examination was performed. According to distal vessel patency, the following CDI classification of CCAO was adopted: type I (patent both distal vessels); type II (isolated patency of external carotid artery); type III (isolated patency of internal carotid artery); and type IV (both distal vessels occluded). Thirty-five (0.5%) cases met the CDI criteria for CCAO. Twenty-nine of those (83%) had at least one patent distal vessel. Ten patients (29%) presented with stroke, 20 (57%) with transient ischemic attacks (TIAs) and five (14%) were asymptomatic. The incidence of stroke was higher in type IV (50%) vs. type II (30%) and in type II vs. type I (10%) lesions. Similarly, TIAs presented more often in type II (67%) and IV (50%) vs. in type I (40%) lesions ( p = 0.002). Retrograde flow in the ophthalmic artery and concomitant severe contralateral carotid artery stenosis were more often related with type II and IV lesions ( p = 0.02 and 0.04, respectively). CCAO is usually accompanied by patent distal vessel(s). The proposed CCAO classification correlates well with the patients' clinical status and may help to better clarify the outcome of this rare entity. Among the main arteries of the developed collateral circulation, only the flow direction in the ophthalmic artery may be of clinical value. (E-mail: asterios@med.uoc.gr)

Internal Carotid Artery Occlusion: Association With Atherosclerotic Disease in Other Arterial Beds and Vascular Risk Factors

The aim of this article is to investigate the association between internal carotid artery occlusion (ICAO) and the presence of atherosclerotic disease and vascular risk factors. The clinical characteristics and risk factors of 120 patients presenting with ICAO were retrospectively reviewed. All patients (n = 120) had at least 1 of the 4 vascular risk factor (diabetes, smoking, hypercholesterolemia, and hypertension); 2, 3, or all 4 risk factors were present in 14 to 82 of the patients (11.7% to 68.3%), 10 to 39 of the patients (8.3% to 32.5%), and 9 of the patients (7.5%), respectively. A total of 84 patients (70%) with ICAO had disease in at least 1 additional vascular bed (aorta, coronary or lower limb arteries). In addition to ICAO, vascular disease was present in 2 and all 3 of these arterial beds in 42 (35%) and 9 (7.5%) patients, respectively. Furthermore, stenosis or occlusion of the ipsilateral or contralateral vertebral arteries was recorded in 19 of 120 patients (15.8%). Regarding the contralateral carotid artery, 1 patient had bilateral ICAO. One patient had contralateral common carotid artery occlusion, and 1 patient was excluded from the analysis because of surgery to the contralateral carotid artery. Of the remaining 117 patients, 34 (29.0%) had less than 50% contralateral carotid artery stenosis. Thirty-two patients (27.4%) had 50% to 69%, and 51 (43.6%) had 70% to 99% stenosis. Ultrasonographic imaging of the carotid plaque of the contralateral carotid artery revealed that 52 of the 120 arteries (43.3%) were uniformly or predominantly echolucent (types I and II, respectively). Fifty-nine (49.2%) were predominantly or uniformly echogenic (types III and IV), and 9 (7.5%) could not be classified. A similar distribution of echomorphology was observed on the occluded side. ICAO is associated with widespread atherosclerotic disease and a high prevalence of vascular risk factors. Detection of ICAO should prompt the investigation of other arterial beds and treatment of risk factors.

Carotid Artery Stenting With Filter Protection in High-Risk Patients Showing Severe Electroencephalographic Alterations During Carotid Endarterectomy

To describe the results and efficacy of stent treatment in patients with carotid stenosis who had aborted carotid endarterectomy procedures due to the appearance of severe electroencephalographic (EEG) alterations. A retrospective study was conducted of 18 patients (11 men; mean age 72 years, range 62-84) with symptomatic high-grade carotid artery stenoses (> or = 70%) who experienced severe EEG alterations during carotid endarterectomy, causing the procedure to be aborted. Twelve patients had shown no hemodynamic alterations during preoperative transcranial Doppler evaluation after external compression of the common carotid artery; the remaining 6 could not be evaluated. The patients were referred for carotid artery stenting (CAS); 7 had contralateral internal carotid artery stenosis and 5 had contralateral occlusion. Endovascular intervention was carried out using standard techniques under filter protection. Follow-up was scheduled at 3, 6, and 12 months. All patients were successfully treated without immediate complications. The EEG did not display any significant alterations during the endovascular procedure. Mean follow-up was 43 months. Magnetic resonance imaging at 6 months showed no signs of cerebral ischemia. Color Doppler ultrasound imaging documented normal stent patency in all patients. Patients with symptomatic severe carotid stenosis (> or = 70%) who are considered at risk due to the appearance of severe EEG alterations during surgical treatment may benefit from CAS with respect to both major and minor complications. Larger studies are needed to confirm these findings.

Tratamento endovascular da doença obstrutiva carotídea em pacientes de alto risco: resultados imediatos

OBJETIVO: Tratamento endovascular - angioplastia carotídea com stent (ACS) - tem se mostrado como opção atual no tratamento da estenose da artéria carótida em pacientes considerados de alto risco para endarterectomia de carótida (ECA). Este trabalho reporta a experiência do Instituto de Cirurgia Vascular e Endovascular (ICVE) de São Paulo nos casos de ACS em pacientes de alto risco. MATERIAL E MÉTODO: Foi realizado um estudo retrospectivo descritivo baseado na análise dos prontuários de 113 pacientes (84 homens e 29 mulheres) submetidos a 130 procedimentos de ACS pelo ICVE, no período de março de 2000 a junho de 2004. A idade média dos pacientes foi de 74 anos (variando de 51 a 86 anos). Os pacientes assintomáticos (55%) apresentavam estenose &gt; 75%, enquanto nos sintomáticos (45%) as lesões encontradas foram &gt; 70%. Foi indicado ACS nos seguintes pacientes: alto risco para ECA (45%), reestenose pós-ECA (15%), estenose carotídea severa bilateral (14%), oclusão da carótida contralateral (12%), bifurcação alta (no nível ou acima da segunda vértebra cervical) (6%), estenose pós-radioterapia (5%) e pescoço hostil (3%). As lesões encontradas localizavam-se na bifurcação carotídea (46%), carótida interna (32%), origem da artéria carótida comum (9%), tronco braquiocefálico (8%) e artéria carótida comum (5%). RESULTADO: Foi observado um total de sete eventos neurológicos (cinco casos de acidente vascular encefálico e dois pacientes que apresentaram ataque isquêmico transitório). A taxa de óbito foi de 0%. A taxa total de complicações (acidente vascular encefálico, acidente isquêmico transitório, óbito) foi de 5,3%. CONCLUSÃO: ACS demonstrou ser um procedimento com baixa taxa de complicações, sendo uma opção segura e eficaz nos pacientes de alto risco para ECA.

Gender-specific risk of perioperative complications in carotid endarterectomy patients with contralateral carotid artery stenosis or occlusion.

Carotid endarterectomy (CEA) has been shown to be effective in stroke prevention in selected patients. Some studies, however, identified gender as an independent risk factor for perioperative CEA complications demonstrating an increased rate of perioperative stroke or death in women. Furthermore, contralateral internal carotid artery (ICA) occlusion has been associated with higher rates of perioperative CEA complications. Therefore, we sought to analyse the gender-specific risk of perioperative CEA complications between patients with or without contralateral ICA stenosis or occlusion. We retrospectively analysed 212 consecutive CEA patients (male = 156, Female = 56) for their gender-specific, perioperative risk of stroke, transient ischemic attack (TIA), restenosis and cardiac complications in the presence (62%) or absence (38%) of a contralateral ICA stenosis/occlusion. In women but not in men, risk of perioperative ischemic events (stroke, TIA) or re-stenosis (p = 0.036) and combined perioperative complications (ischemic events, re-stenosis or cardiac complications; 38.2 % vs. 9.1%; p = 0.028) was significantly increased in the presence of a contralateral ICA stenosis or occlusion. Furthermore, in the presence of a contralateral ICA stenosis/occlusion the number of perioperative ischemic events (p = 0.008) and combined perioperative complications (38.2 % vs. 14.3%; p = 0.006) was significantly higher in female than in male patients. Our study suggests that women with contralateral ICA stenosis or occlusion may have a significantly higher risk for perioperative CEA complications than other subgroups of CEA patients. This risk increase seems to be gender-specific and, if confirmed in larger prospective studies, may influence ICA stenosis therapy in the presence of a contralateral ICA stenosis/occlusion in female patients.

Disease progression in contralateral carotid artery is common after endarterectomy.

Although the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and the Asymptomatic Carotid Atherosclerosis Study (ACAS) have helped to define the role of carotid endarterectomy (CEA) for both symptomatic and asymptomatic lesions, the role of surveillance of the contralateral carotid artery remains unclear. The purpose of this study was to determine the progression of contralateral carotid artery disease with serial duplex ultrasound scans after CEA compared with the recurrent stenosis rate for the carotid artery ipsilateral to the CEA. From January 1990 to December 2000, 473 CEA procedures were performed at a Veterans Affairs Medical Center. From this group we identified 279 patients who had undergone first-time CEA, as well as preoperative duplex scanning and postoperative duplex scanning at least once, in the vascular laboratory. At each visit stenosis of the internal carotid artery (ICA) was categorized as none (0%-14%), mild (15%-49%), moderate (50%-79%), severe (80%-99%), or occluded. Analysis of probability of freedom from progression was determined. Progression was defined as an increase in ICA stenosis 50% or greater or increase to a higher category of stenosis if baseline was 50% or greater. The Cox proportional hazards model was used for data analysis. Mean patient age was 65.7 years (range, 33-100 years). The 1024 carotid duplex ultrasound scanning examinations performed (mean, 3.7; range, 2-13) included the last study done before the index CEA and all studies done after the CEA. Mean follow-up was 27 months (range, 1-137 months). Forty-six patients were found to have contralateral carotid occlusion at initial duplex scanning, and were therefore excluded from the contralateral progression analysis. Contralateral progression was more frequent than ipsilateral recurrent stenosis at long-term follow-up (P <.01). Annual rates of "any progression" and "progression to severe stenosis or occlusion" were 8.3% and 4.4%, respectively, for contralateral arteries, and 4.3% and 2.4%, respectively for ipsilateral arteries. As a result of surveillance, 43 contralateral CEAs (19% of initial cohort) were performed. Carotid stenosis regressed in 25 arteries (10.7%). Baseline clinical and demographic factors did not predict disease progression. Baseline contralateral stenosis did not predict time to "any progression," but was a strong predictor of "progression to severe stenosis or occlusion" (P <.001). After CEA, we identified an 8.3% annual rate of progression of contralateral carotid artery stenosis and a 4.4% annual rate of progression to severe stenosis or occlusion. Baseline contralateral stenosis was significantly predictive of progression to severe stenosis or occlusion. Clinical and demographic factors were not helpful in predicting which patients would have disease progression. These data may help in assessing the cost effectiveness of duplex scanning surveillance after CEA.

US of neurovascular occlusive disease: interpretive pearls and pitfalls.

Ultrasonography (US) of the head and neck is a convenient but operator-dependent screening tool for detection and diagnosis of neurovascular occlusive disease. In US examination of the extracranial carotid arteries, stenosis is most commonly graded according to the peak systolic Doppler velocity in the region of maximal luminal narrowing rather than according to the percentage of atheromatous plaque occupying the lumen. However, the peak systolic velocity is not always reliable in estimation of the degree of stenosis. General diagnostic pitfalls include technical difficulties with scanning, failure to review the spectral waveform patterns, the presence of additional stenotic lesions, and anatomic variants. Specific examples of pitfalls include tandem lesions, differentiation of pseudo-occlusion from true total occlusion, pseudonormalization of velocities in cases of very severe stenosis, lesions of the carotid artery origin or aortic valve, progression of subclavian steal, underestimation of severe stenosis due to heavily calcified plaque, a persistent trigeminal artery, and contralateral carotid artery stenosis. Although conventional angiography remains the standard of reference for assessment of carotid artery disease, recognition of these common sources of error in US can improve the accuracy of this noninvasive test in diagnosis of carotid artery occlusion.

Cerebral hemodynamics in patients with carotid artery occlusion and contralateral moderate or severe internal carotid artery stenosis.

The purpose of this study was to evaluate cerebral hemodynamics in patients suffering from occlusion of the carotid artery (CA) and contralateral CA stenosis. Using transcranial Doppler ultrasonography, the cerebrovascular reactivity to hypercapnia in the middle cerebral arteries was evaluated by calculating the breath-holding index (BHI) of 69 symptomatic patients suffering from internal CA (ICA) occlusion and moderate or severe contralateral ICA stenosis. To evaluate which variables influenced BHIs ipsilateral to the site of ICA occlusion, a multiple stepwise linear regression analysis was performed that included the following factors: patient age, percentage of contralateral ICA stenosis, contralateral BHI, number of collateral pathways, and presence of hypertension, diabetes, smoking, and hyperlipidemia. An analysis of variance was conducted to evaluate the impact of the type of collateral vessels on the BHI. A regression analysis showed that the BHI ipsilateral to the site of ICA occlusion could be accounted for by the contralateral BHI (which was entered at the first step of the analysis, p < 0.001) and by the number of collateral pathways (which was entered at the second step, p = 0.033). Neither the degree of contralateral ICA stenosis nor the other variables could be added to improve the model. The analysis demonstrated that the absence of collateral pathways and the presence of the anterior communicating artery (ACoA) alone were associated with lower BHI values than those found in the presence of two or three collateral vessels, regardless of the presence of an anterior collateral pathway. On the basis of these data one can infer that the cerebral hemodynamic status of patients with occlusive disease of the CA is influenced by individual anatomical and functional characteristics. Because improvement in contralateral hemodynamics after surgical correction of an ICA stenosis can only be expected in the presence of an ACoA, the planning of strategies for influencing cerebral blood flow distal to an ICA occlusion and, in particular, the consideration of a contralateral carotid endarterectomy, should be preceded by a careful evaluation of the intracranial hemodynamic adaptive status of the patient. Particular attention should be paid to cerebrovascular reactivity and the number and type of collateral vessels that are present.

Effect of contralateral carotid artery stenosis on carotid ultrasound velocity measurements.

Carotid ultrasonography is being increasingly performed as the sole investigation to assess internal carotid artery (ICA) stenosis. A potential source of error in using ultrasound peak systolic velocity (PSV) measurements is that the redistribution of blood flow due to severe stenosis in a contralateral carotid artery may lead to artificially elevated values. Ultrasonography was performed before and after carotid endarterectomy in symptomatic patients who participated in the North American Symptomatic Carotid Endarterectomy Trial (NASCET). The mean change in PSV in the unoperated artery was assessed across all degrees of angiographically defined stenosis. A simple theoretical resistance model of the cerebral circulation was also derived. Complete bilateral ultrasound examinations were performed within 90 days of the initial scan in 386 patients. In the presence of a contralateral severe (70% to 99%) ICA stenosis, the PSV in the unoperated artery was artificially elevated by a mean of 84 cm/s (P:=0.03; 95% CI, 10 to 159 cm/s). The mean elevation was less pronounced for lesser degrees of stenosis (11 to 21 cm/s). Small elevations (3 to 12 cm/s) were observed when the contralateral artery had <70% stenosis. The patterns of observed results were congruent with those from the theoretical model. The present study showed that a severely stenosed contralateral ICA can artificially elevate ultrasound PSV. Since the effect was greatest when bilaterally severe stenoses were present, caution must be exercised when assessing the degree of ICA stenosis on the basis of ultrasonography PSV measurements alone.

Carotid artery angioplasty and use of stents in high-risk patients with contralateral occlusions.

The risks associated with carotid endarterectomy (CEA) are increased in the presence of contralateral carotid artery (CA) occlusion. The 30-day stroke and death rate for patients in the North American Symptomatic Carotid Endarterectomy Trial (NASCET) who had contralateral CA occlusion was 14.3%. The authors analyze their experience with angioplasty and/or stent placement in patients with contralateral CA occlusion to determine the safety and efficacy of endoluminal revascularization in this subgroup. Twenty-six procedures were evaluated in 23 patients with high-grade CA stenosis and contralateral CA occlusion. The first 15 procedures were evaluated retrospectively, and the next 11 prospectively. All patients had severe medical comorbidities and were considered too high risk for CEA, even without considering the contralateral occlusion. Clinical follow-up review was performed an average of 18 months later (median 15 months). The average ipsilateral CA stenosis according to NASCET criteria was 78% preprocedure and 5% postprocedure. There were no changes in neurological or functional outcome immediately postoperatively in any patient. The 30-day postoperative stroke and death rates were zero. However, there was one symptomatic femoral hematoma that resolved without surgery. At follow up, there were three patients who had suffered stroke or death. One patient died secondary to respiratory arrest at 2 months; one died secondary to prostate carcinoma at 12 months; and one patient experienced a minor stroke contralateral to the treated artery at 41 months. Despite the substantial preoperative risk factors in patients in this series, the 30-day stroke and death rate for angioplasty and/or stent placement appears to be lower than that of CEA in patients with contralateral occlusions.

Outcome of the Contralateral Carotid Artery in Patients Having Undergone Ipsilateral Carotid Endarterectomy: Results of Selective Management

Purposes: To evaluate the natural history of the carotid artery in patients who have undergone endarterectomy of the opposite carotid artery, study its relation to new neurologic events by clinical follow-up and serial duplex scanning, review the literature for management guidelines at present, and evaluate the impact on these guidelines from recently published prospective, randomized trials. Methods: A retrospective study of 275 consecutive patients who underwent carotid endarterectomy (CEA) from December 1985 through December 1992. Results: Of 275 patients, 115 were excluded (lost to follow-up, preoperative contralateral carotid occlusion, perioperative death or stroke) leaving 160 patients as the final study group. Progression of contralateral stenosis from &lt;50% to 50-79% occurred in 13/113 patients (11.5%), all asymptomatic; from 50-79% to 80-99% in 10/38 patients (26.3%), (two symptomatic-one transient ischemic attack [TIA] and one stroke-&lt;50% to 80-99% in one patient who was asymptomatic); no patient progressed to total occlusion. All nine patients with an initial contralateral stenosis 80-99% remained asymptomatic prior to subsequent CEA. Neurologic events referable to the contralateral carotid distribution occurred in 10 patients of 160 (6.3%) at a mean of 12.8 months after initial surgery, six TIAs and four strokes, none of which was heralded by TIA. Thus 24 patients showed progression of stenosis, with two (8.3%) manifesting symptoms. Of the other 136 patients without progression of stenosis, eight (5.9%) developed symptoms. Conclusions: Our data and a review of the literature does not support an aggressive approach to the contralateral carotid artery stenosis. Based on NASCET and ACAS, however, new guidelines for management are suggested.

Progression of non-operated symptomatic and contralateral asymptomatic internal carotid artery stenosis $ge; 50% V. Zbornikova, L. Skoglund, C. Lassvik. Departments of Neurology and Clinical Physiology, University Hospital, Link�ping, Sweden

Progression of non-operated symptomatic and contralateral asymptomatic internal carotid artery stenosis $ge; 50% V. Zbornikova, L. Skoglund, C. Lassvik. Departments of Neurology and Clinical Physiology, University Hospital, Link�ping, Sweden

Progression of non-operated symptomatic and contralateral asymptomatic internal carotid artery stenosis ≥ 50%: V. Zbornikova, L. Skoglund, C. Lassvik. Departments of Neurology and Clinical Physiology, University Hospital, Linko¨ping, Sweden

Progression of non-operated symptomatic and contralateral asymptomatic internal carotid artery stenosis ≥ 50%: V. Zbornikova, L. Skoglund, C. Lassvik. Departments of Neurology and Clinical Physiology, University Hospital, Linko¨ping, Sweden

Vasomotor reactivity and pattern of collateral blood flow in severe occlusive carotid artery disease.

The compromise of cerebrovascular autoregulation in severe occlusive carotid artery disease depends on the functional capacity of collateral pathways. In previous reports correlating hemodynamic disturbances with collateral pathways, collateral blood supply was often evaluated by invasive cerebral angiography. In this study noninvasive transcranial Doppler ultrasound was used to determine both collateral pathways and vasomotor reactivity. With the use of blood flow direction, compression tests, and evident side-to-side asymmetries of blood velocities, the collateral supply through the anterior and posterior communicating arteries, the ophthalmic artery, and leptomeningeal anastomoses was evaluated by transcranial Doppler ultrasound in 48 patients (42 men, 6 women; mean +/- SD age, 59 +/- 9 years) with occlusion (n = 36) or stenosis of more than 90% (n = 12) of one internal carotid artery. Ipsilateral vasomotor reactivity was determined by the percent increase of middle cerebral artery mean blood velocity with the use of (1) the breath-holding maneuver and (2) acetazolamide (1 g IV) as vasodilatory stimulus. Additional stenoses (50% to < 90%) of the contralateral internal carotid artery were present in 20 of the 48 patients. Vasomotor reactivity was not affected by the presence of a contralateral internal carotid artery stenosis. Both vasodilatory stimuli similarly indicated poor vasomotor reactivity when an ophthalmic or a leptomeningeal pathway accompanied an anterior communicating artery pathway compared with a lone anterior communicating artery pathway (P < .05). The acetazolamide challenge indicated significantly better preserved vasomotor reactivity when blood supply was provided through a lone anterior communicating artery pathway (66 +/- 30%) than through an anterior and posterior communicating artery pathway (33 +/- 20%, P < .05), whereas the breathholding method failed to show such a difference. The presence of an ophthalmic artery pathway may provide the first evidence of disturbed vasomotor reactivity. The use of cerebral angiography to evaluate collateral pathways must be considered carefully since transcranial Doppler ultrasound is a reliable noninvasive alternative.

Contralateral external carotid-to-external carotid artery (half-collar) saphenous vein graft for common carotid artery occlusion

In a patient having common carotid artery occlusion complicated with contralateral internal carotid artery stenosis, a saphenous vein bypass graft was performed from the contralateral external carotid artery to the ipsilateral external carotid artery simultaneously with contralateral carotid endarterectomy. The bypass was patent 1 year later and the patient was free from fainting spells. Among a number of the reconstructive surgical procedures, this “half-collar bypass” can be placed adequately in the subcutaneous soft tissue so that head or mandibular movement does not displace or compress the graft. Intraoperative hemodynamic measurements were considered useful in determining surgical options.

Embolic infarcts of carotid origin differ in size and site with contralateral carotid patency

Carotid emboli cause small infarcts in the ipsilateral hemisphere in rats when the contralateral carotid artery is fully patent. With contralateral carotid occlusion, embolic infarcts, both large and small, occur with equal proportions in both hemispheres. To determine if emboli also cross to the territory of a stenotic carotid artery, we combined high grade (78–96%) stenosis of the left common carotid artery with photochemically-induced (laser irradiation 632 nm, 200 mW/cm 2, 15 min; intravenous Photofrin II, 12.5 mg/kg) embolism from the right common carotid artery in 12 rats. Ninety-eight cerebral infarcts occurred in 9 experimental animals, with eight infarcts being large (> 2.5 mm). The mean proportions of infarcts and emboli on the left were 25% and 19%, respectively. These results suggest that contralateral carotid artery stenosis, like occlusion, will influence the site and size of embolic infarcts and that the “symptomatic” carotid artery cannot always be determined by the side of the cerebral infarct.

The Evolution of Carotid and Coronary Artery Disease After Operation for Carotid Stenosis

We followed 278 consecutive patients undergoing carotid artery surgery between January 1985 and December 1989 using a computerized surveillance program file with automatic carotid and coronary artery follow-up investigations every six months. Combined postoperative neurologic mortality and morbidity was 1.7%. During the mean follow-up period of 30 months, 10 patients died, four due to myocardial infarction. Actuarial rates of survival and freedom from cerebral vascular accidents at 36 months were 94% and 95.8%, respectively. No fatalities due to cerebral vascular accidents occurred during follow-up. Eleven patients had myocardial infarction, an actuarial rate of 6% at 36 months; 18 patients experienced angina pectoris, while seven sustained silent electrical myocardial ischemia. Findings on myocardial angioscintiscans and coronary artery arteriograms led to four aortocoronary bypasses and seven percutaneous coronary artery dilatations. Duplex scanning documented three asymptomatic carotid restenoses of > or = 80%, which were operated upon, and 32 contralateral carotid artery stenoses ranging between 80% and 99%, 24 of which were asymptomatic. Twenty-eight patients underwent secondary contralateral carotid artery revascularization. No one with contralateral carotid artery stenosis < 80% experienced a carotid artery ischemic event. These results clearly show the value of cardiac and neurologic surveillance of patients operated on for carotid artery stenosis.

Contralateral internal carotid artery stenosis or occlusion: Pitfall of correct ipsilateral classification—A study performed with color-flow imaging

The records of 183 patients who had undergone color-flow imaging of the extracranial carotid arteries and subsequent bilateral cerebral arteriography were reviewed to determine whether contralateral carotid arterial disease adversely affects the accuracy of duplex scanning by increasing the velocity of flow in the ipsilateral artery. In 83 arteries the contralateral internal carotid artery had a diameter reduction ≥80%; in the remaining 283, the contralateral artery was less severely diseased. Noninvasive findings correlated less well with arteriography in the group with contralateral disease (κ = 0.69 ± 0.06) than in the group with less severe contralateral stenosis (κ = 0.78 ± 0.03), and the incidence of false-positive errors was significantly (p = 0.02) higher (18% vs 7%). For all categories of ipsilateral stenosis, the mean peak systolic and end-diastolic velocities were elevated in the group with severe contralateral disease. This effect was most evident in the 50% to 79% diameter reduction category, especially in reference to the end-diastolic velocity (p = 0.2). However, the data correlating velocity with diameter reduction were widely scattered, indicating that the effect of contralateral disease is inconsistent. We conclude that severe disease of the contralateral carotid artery can lead to overreading ipsilateral disease and that velocity determinations should be interpreted cautiously under such circumstances.