Distal Internal Carotid Artery Occlusion Research Articles

Distal Endovascular Occlusion for Incomplete Occlusion of Cavernous Carotid Aneurysms after High-flow Bypass and Cervical Internal Carotid Artery Ligation.

Internal carotid artery (ICA) ligation for placing a high-flow extracranial-intracranial (EC-IC) bypass is used in patients with aneurysms on the cavernous portion of the ICA. Recanalization and rupture after proximal ICA ligation can occur. We present four patients who underwent endovascular distal ICA occlusion and report our surgical technique and treatment results. We ligated the ICA to place an EC-IC bypass using a radial artery (RA) graft. Failure to obtain spontaneous occlusion in the distal region required endovascular treatment an average of 219 days later. A guide catheter was placed in the common carotid artery, a guide or distal access catheter was introduced in the RA graft from the external carotid artery, and a microcatheter was navigated into the cavernous aneurysm through the RA graft. Using detachable coils, endovascular ICA occlusion was from just distal to the aneurysmal neck to a site proximal to the origin of the ophthalmic artery. Aneurysmal occlusion was completed by endovascular occlusion of the distal ICA. Complications were RA graft stenosis and transient consciousness disturbance due to local subarachnoid hemorrhage. Outpatient follow-up for a mean of 109.5 months revealed no recurrences. Distal occlusion of the ICA through the implanted RA graft is simple and presents a low risk for cerebral infarction due to thrombus formation during the procedure. To treat cavernous carotid aneurysms that do not disappear after placing the EC-IC bypass after ICA ligation at the aneurysmal neck, we offer our procedure as a treatment option.

Functional Aplasia of the Contralateral A1 Segment Influences Clinical Outcome in Patients with Occlusion of the Distal Internal Carotid Artery.

Background: The importance of an A1 aplasia remains unclear in stroke patients. In this work, we analyze the impact of an A1 aplasia contralateral to an acute occlusion of the distal internal carotid artery (ICA) on clinical outcomes. Methods: We conducted a retrospective study of consecutive stroke patients treated with mechanical thrombectomy at 12 tertiary care centers between January 2015 and February 2021 due to an occlusion of the distal ICA. Functional A1 aplasia was defined as the absence of A1 or hypoplastic A1 (>50% reduction to the contralateral site). Functional independence was measured by the modified Rankin Scale (mRS ≤ 2). Results: In total, 81 out of 1068 (8%) patients had functional A1 aplasia contralateral to distal ICA occlusion. Patients with functional contralateral A1 aplasia were more severely affected on admission (median NIHSS 18, IQR 15–23 vs. 17, IQR 13–21; aOR: 0.672, 95% CI: 0.448–1.007, p = 0.054) and post-interventional ischemic damage was larger (median ASPECTS 5, IQR 1–7, vs. 6, IQR 3–8; aOR: 1.817, 95% CI: 1.184–2.789, p = 0.006). Infarction occurred more often within the ipsilateral ACA territory (20/76, 26% vs. 110/961, 11%; aOR: 2.482, 95% CI: 1.389–4.437, p = 0.002) and both ACA territories (8/76, 11% vs. 5/961, 1%; aOR: 17.968, 95% CI: 4.979–64.847, p ≤ 0.001). Functional contralateral A1 aplasia was associated with a lower rate of functional independence at discharge (6/81, 8% vs. 194/965, 20%; aOR: 2.579, 95% CI: 1.086–6.122, p = 0.032) and after 90 days (5/55, 9% vs. 170/723, 24%; aOR: 2.664, 95% CI: 1.031–6.883, p = 0.043). Conclusions: A functional A1 aplasia contralateral to a distal ICA occlusion is associated with a poorer clinical outcome.

Factors Distinguishing Proximal and Distal Internal Carotid Artery Occlusions in Patients with Acute Ischemic Stroke.

Acute internal carotid artery (ICA) occlusions cause extensive brain ischemia. Accurate determination of the occlusion site facilitates rapid revascularization interventions and improves prognosis. However, proximal ICA occlusions, as determined with computed tomography (CT) angiography, often are located more distally. Therefore, we assessed clinical and imaging factors associated with the accurate determination of occlusion sites. In this observational study, we evaluated 102 patients who presented acute ischemic stroke symptoms and had a CT angiography within 6 h, showing proximal ICA occlusion. The participants were divided into two groups, depending on whether there was correspondence between digital subtraction angiography and CT angiography regarding the occlusion location. Proximal occlusions were, accordingly, categorized as “true” (correspondence) or “false” (no correspondence; distal). Demographic, clinical, and imaging features were analyzed. Multivariate regression analysis was performed to identify factors predicting the correspondence between actual ICA occlusion sites and those detected by CT angiography. The shape (Odds ratios, OR = 646.584; Confidence interval, CI = 21.703–19263.187; p < 0.001) and the length (OR = 0.696; CI = 0.535–0.904; p = 0.007) of the ICA occlusion and atrial fibrillation (OR = 0.024; CI = 0.002–0.340; p = 0.006) were significant factors. The cut-off length of ICA stump at 6.2 mm, the sensitivity was 71%, and the specificity was 70% (area under the ROC curve = 0.767).

Thrombectomy for acute ischemic stroke patients with isolated distal internal carotid artery occlusion: a retrospective observational study

PurposeAcute stroke patients presenting with a distal internal carotid artery occlusion and patent carotid terminus, allowing for collateral flow via the circle of Willis, may have a more favorable natural history. Therefore, benefit of endovascular treatment (EVT) is less evident. We performed an exploratory analysis of EVT results compared to conservative treatment in patients with ‘carotid-I’ occlusions.MethodsWe report on EVT-treated and non-EVT-treated patients with carotid-I occlusions from the MR CLEAN Registry, MR CLEAN trial, and our comprehensive stroke center. CT-angiography was reviewed on primary collateral patency and choroid plexus enhancement. Perfusion deficits were assessed on CT-perfusion (CTP). Clot migration was assessed by comparing clot location on baseline CTA to its location on periprocedural digital subtraction angiography. Outcomes included 90-day functional independence (mRS 0–2), successful reperfusion and mortality.ResultsWe included 51 patients. Forty-one patients received EVT, ten patients did not. Intravenous thrombolysis was administered in 32 (78%) EVT-treated patients and 6 (60%) non-EVT-treated patients. CTP, available for 17 patients, showed hypoperfusion on cerebral blood flow maps in 13 (76%) patients. Successful reperfusion after EVT occurred in 23 (56%), and clot migration in 8 patients (20%). Functional independence was achieved in 54% (21/39) of EVT-treated and in 10% (1/10) of non-EVT-treated patients. Mortality was 26% (10/39) and 30% (3/10), respectively. Anterior choroidal artery patency and choroid plexus enhancement were positively associated with functional independence.ConclusionIn our population, data suggest improved outcomes after EVT in carotid-I occlusion patients and provide no arguments to withhold EVT in these patients.

Differentiating pseudo-occlusion from true occlusion of proximal internal carotid artery in acute ischemic stroke on CT angiography

ObjectiveA lack of visualization of the proximal internal carotid artery (ICA) on computed tomography angiography (CTA) in acute ischemic stroke may be caused by an atherosclerotic occlusion or a pseudo-occlusion by a massive thrombus in the ICA. Pseudo-occlusion of the proximal ICA is caused by stagnant flow from a distal ICA occlusion. The purpose of this study aimed to use imaging findings of CTA to differentiate pseudo-occlusions from true occlusions of the proximal ICA. Patients and methodsAll eligible patients undergoing endovascular treatment after CTA from January 2013 to March 2018 were respectively reviewed. Patients with <2 cm of ICA on CTA images were enrolled in this study. CTA images were classified as having a beak, dome, or flat pattern. ResultsOur sample included a total of 66 eligible patients (true occlusion: 31, pseudo-occlusion: 35). The total length of opacification of the proximal ICA in the pseudo-occlusion group was significantly higher compared to that in the true occlusion group (13.9 ± 4.0 vs. 6.1 ± 4.8, p < 0.001). A beak pattern of the proximal ICA on CTA images was significantly higher in the pseudo-occlusion group (82.9% vs. 16.1%, p < 0.001), but a flat pattern was significantly higher in the true occlusion group (58.1% vs. 0%, p < 0.001). Gradual contrast decline of the proximal ICA on CTA images only appeared in the pseudo-occlusion group (51.4%, p < 0.001). ConclusionsOn CTA, imaging patterns of the proximal ICA can be differentiated between true occlusions and pseudo-occlusions.

Moyamoya vasculopathy with anti-SCL-70 antibodies: A case report and review of the literature

Moyamoya disease and syndrome constitute two distinct pathological entities with a primary finding of progressive distal internal carotid artery occlusion, which results in either an ischemic or hemorrhagic sequela. While the disease entity stands as a primary arterial vasculopathy, moyamoya syndrome represents a secondary vasculopathy associated with a systemic inflammatory process. We describe a patient with an ischemic stroke and angiographic findings of moyamoya in the setting of positive antinuclear antibodies and anti-Scl-70 antibodies with clinical features of scleroderma on exam. A review of current literature identified three similar cases where immunosuppression in addition to secondary stroke prevention led to reduced frequency of neurological sequelae. These cases plus our own demonstrate that patients with moyamoya vasculopathy in association with anti-Scl 70 antibodies exist on a spectrum with either predominant scleroderma features or neurological symptoms. There are a limited number of cases reported of moyamoya vasculopathy in association with anti-Scl 70 antibodies. This case report demonstrates that not only may the association be more common than we think, but that it exists on a dynamic spectrum with variable clinical presentation and course.

Slow Collateral Flow Is Associated with Thrombus Extension in Patients with Acute Large-Artery Occlusion.

It is still poorly understood about the dynamic changes of the thrombus after intravenous thrombolysis and how the remaining thrombus affects clinical outcome in human stroke. Collateral flow was assumed to help to deliver endo/exogenous tissue-type plasminogen activator to the clot. We aimed to analyze the impact of collateral flow on the dynamic changes of the thrombus in patients with acute large-artery occlusion who received intravenous thrombolysis. We reviewed consecutive patients with acute ischemic stroke with M1 segment or distal internal carotid artery occlusion who underwent multimodal MR imaging or CT perfusion before and 24 hours after intravenous thrombolysis without recanalization. Patients were divided into 3 groups (thrombus extension, shortening, and no change) according to thrombus-length change between baseline and 24 hours. Collateral flow was measured with arrival time delay and the collateral scoring system. Poor outcome was defined as a 3-month modified Rankin Scale score of ≥3. Among 51 patients, 18 (35.3%) had thrombus extension, 14 (27%) had thrombus shortening, and 19 (37.3%) had thrombus without change. Arrival time delay was independently associated with thrombus extension (OR = 1.499; 95% CI, 1.053-2.135; P = .025). Similarly, the collateral score on the peak artery phase was independently associated with thrombus extension (OR = 0.456; 95% CI, 0.211-0.984; P = .045), whereas baseline National Institutes of Health Stroke Scale score (OR = 0.768; 95% CI, 0.614-0.961; P = .021) and baseline thrombus length (OR = 1.193; 95% CI, 1.021-1.394; P = .026) were associated with thrombus shortening. All patients with thrombus extension had poor outcomes. Slow collateral flow was related to thrombus extension in patients with large-artery occlusion without recanalization after intravenous thrombolysis.

Diagnostic accuracy of emergency CT angiography for presumed tandem internal carotid artery occlusion before acute endovascular therapy

BackgroundExtracranial internal carotid artery (ICA) occlusion can be overestimated on emergent single phase CT angiography (CTA) of stroke patients with isolated intracranial ICA occlusion. We aimed to measure the ability...

Permeability Surface of Deep Middle Cerebral Artery Territory on Computed Tomographic Perfusion Predicts Hemorrhagic Transformation After Stroke.

Permeability surface (PS) on computed tomographic perfusion reflects blood-brain barrier permeability and is related to hemorrhagic transformation (HT). HT of deep middle cerebral artery (MCA) territory can occur after recanalization of proximal large-vessel occlusion. We aimed to determine the relationship between HT and PS of deep MCA territory. We retrospectively reviewed 70 consecutive acute ischemic stroke patients presenting with occlusion of the distal internal carotid artery or M1 segment of the MCA. All patients underwent computed tomographic perfusion within 6 hours after symptom onset. Computed tomographic perfusion data were postprocessed to generate maps of different perfusion parameters. Risk factors were identified for increased deep MCA territory PS. Receiver operating characteristic curve analysis was performed to calculate the optimal PS threshold to predict HT of deep MCA territory. Increased PS was associated with HT of deep MCA territory. After adjustments for age, sex, onset time to computed tomographic perfusion, and baseline National Institutes of Health Stroke Scale, poor collateral status (odds ratio, 7.8; 95% confidence interval, 1.67-37.14; P=0.009) and proximal MCA-M1 occlusion (odds ratio, 4.12; 95% confidence interval, 1.03-16.52; P=0.045) were independently associated with increased deep MCA territory PS. Relative PS most accurately predicted HT of deep MCA territory (area under curve, 0.94; optimal threshold, 2.89). Increased PS can predict HT of deep MCA territory after recanalization therapy for cerebral proximal large-vessel occlusion. Proximal MCA-M1 complete occlusion and distal internal carotid artery occlusion in conjunction with poor collaterals elevate deep MCA territory PS.

Moyamoya Disease, Still a Mysterious Disorder.

Moyamoya disease (MMD) is a chronic occlusive cerebrovascular disease characterized by progressive stenosis at the terminal portion of the internal carotid artery and an abnormal vascular network at the base of the brain. The etiology remains unknown, and the treatment is not satisfactory. In this issue of Journal of Stroke, important review papers on MMD are published. They showed that genetic variations of RNF213 in the 17q25-ter region make it an important susceptibility gene, and that MMD is most common in East Asian countries such as Korea and Japan. These epidemiological characteristics may be attributed to the high prevalence of the susceptibility gene in this region. Other issues including recent advances in surgical and interventional therapy are also summarized. However, MMD is still a mysterious disorder. MMD is diagnosed on the basis of imaging findings: bilateral (or unilateral) distal internal carotid artery occlusion and basal collaterals. However, simple middle cerebral artery stenosis may evolve into MMD over time, and intracranial atherosclerosis may angiographically mimic MMD. Although gene testing is useful in the differential diagnosis, questions remain. RNF gene polymorphism is found to be present in 1/4 of patients with non-MMD intracranial atherosclerosis in East Asia [1], suggesting that it is not specific for MMD. In practice, when we encounter a patient with RNF gene variation and intracranial arterial disease that is not angiographically consistent with MMD, we are not sure whether this case is of atypical MMD or of atherosclerosis. Given the fact that RNF gene polymorphism is not uncommon in the Japanese and Koreans and only a few develop MMD, RNF may simply be a susceptibility gene, and the final clinical presentation, that is, MMD, intracranial atherosclerosis, or no vascular lesion, may depend on the nature of a secondary insult or perhaps other genetic variations. This is a puzzling issue, and a recent case report of combined pathology (both MMD and atherosclerosis) [2] has provided further confusion. Reviews on this issue showed that MMD cases are also found in Western countries, and the prevalence is increasing worldwide. Are the characteristics of MMD in the East and West the same? Is the real incidence increasing or are we simply detecting more cases with advanced imaging tools? Other difficult questions are; why are there two peaks of age, around 10 years and at 30-45 years? Why are patients 20-30 years old relatively unaffected? Are antiplatelet agents useful for MMD patients? Is surgical revascularization therapy beneficial for patients presenting with hemorrhagic stroke? In patients with asymptomatic MMD, what is the risk of future stroke and what are the predictive factors? Is there any way to prevent the progression of the disease? The reviews provide more questions than solutions, and it seems that the answers remain far off. However, we have to realize that polymorphism in RNF 213 gene was completely unheard of until 10 years ago. Ten years from now, with continued research, we might be involved in clinical trials that examine ways to prevent the development of MMD in young individuals with a susceptible gene.

Methodological issues for designing and conducting a multicenter, international clinical trial in Acute Stroke: Experience from ARTSS-2 trial

BackgroundWe describe innovations in the study design and the efficient data coordination of a randomized multicenter trial of Argatroban in Combination with Recombinant Tissue Plasminogen Activator for Acute Stroke (ARTSS-2). MethodsARTSS-2 is a 3-arm, multisite/multiregional randomized controlled trials (RCTs) of two doses of Argatroban injection (low, high) in combination with recombinant tissue plasminogen activator (rt-PA) in acute ischemic stroke patients and rt-PA alone. We developed a covariate adaptive randomization program that balanced the study arms with respect to study site as well as hemorrhage after thrombolysis (HAT) score and presence of distal internal carotid artery occlusion (DICAO). We used simulation studies to validate performance of the randomization program before making any adaptations during the trial. For the first 90 patients enrolled in ARTSS-2, we evaluated performance of our randomization program using chi-square tests of homogeneity or extended Fisher's exact test. We also designed a four-step partly Bayesian safety stopping rule for low and high dose Argatroban arms. ResultsHomogeneity of the study arms was confirmed with respect to distribution of study site (UK sites vs. US sites, P=0.98), HAT score (0–2 vs. 3–5, P=1.0), and DICAO (N/A vs. No vs. Yes, P=0.97). Our stopping thresholds for safety of low and high dose Argatroban were not crossed. Despite challenges, data quality was assured. ConclusionsWe recommend adaptive designs for randomization and Bayesian safety stopping rules for multisite Phase I/II RCTs for maintaining additional flexibility. Efficient data coordination could lead to improved data quality.

Acute Ischemic Stroke in a 12-Year-Old Successfully Treated With Mechanical Thrombectomy

We report the case of a healthy 12-year-old girl with an acute ischemic stroke successfully treated with mechanical thrombectomy. The child was referred to our hospital 6 hours after sudden onset of severe headache and left hemiparesis. Cerebral angiography findings were consistent with right distal internal carotid artery occlusion in addition to ipsilateral middle cerebral artery occlusion. Subsequent mechanical thrombectomy with Solitaire AB device resulted in complete vessel recanalization. The patient experienced progressive neurologic improvement with good clinical recovery at the 3-month follow-up. To our knowledge, only 3 cases of primary mechanical thrombectomy in children have been previously reported in the literature. Safety and efficacy data for endovascular therapies in pediatric acute ischemic stroke are lacking. We propose mechanical thrombectomy as an option in children with significant neurologic deficits and proven arterial occlusion, especially when the therapeutic window for intravenous thrombolysis has been exceeded.

Endovascular Treatment of Distal Internal Carotid Artery Occlusions with Retrievable Stents

Background: Acute stroke due to distal intracranial internal carotid artery (ICA) occlusion has a poor natural history. Outcome in patients who receive intravenous tissue plasminogen activator (tPA) is also unsatisfactory. The objective of this study is to evaluate the effectiveness and safety of endovascular treatment with retrievable stents in these patients. Methods: Data from a prospective register of patients with acute stroke treated with an endovascular procedure in a single centre were analysed. Results: A total of 20 patients with distal ICA occlusion were collected. Mean baseline National Institutes of Health Stroke Scale score was 18. Eight cases (40%) had received previous intravenous tPA. Mean time from stroke to recanalization was 393 min. Retrievable stents with proximal occlusion and aspiration were used in all cases. In 3 patients, 2 retrievable stents were used simultaneously. Complete recanalization (thrombolysis in cerebral infarction 2b/3) was accomplished in 85% of cases. A favourable clinical outcome (modified Rankin Scale score 0-2) was achieved in 13 patients (65%). Mortality occurred in 2 cases (10%). Conclusions: Endovascular treatment of patients with distal ICA occlusion seems safe and effective. Retrievable stents may be the treatment of choice, although randomized clinical trials are necessary. The use of 2 retrievable stents at the same time could be an alternative technique useful in thrombi of larger size.

Emergent stent-assisted angioplasty of extracranial internal carotid artery and intracranial stent-based thrombectomy in acute tandem occlusive disease: technical considerations

ObjectiveTandem occlusions of the internal carotid artery (ICA) and a major intracranial artery respond poorly to intravenous thrombolytic therapy, and are usually managed by endovascular means. This study describes experience...

Outcome of forced-suction thrombectomy in acute intracranial internal carotid occlusion

ObjectivesIschemic stroke from acute intracranial distal internal carotid artery (ICA) occlusion usually carries a poor prognosis. Despite the intra-arterial revascularization therapies, the results are still unsatisfactory. The aim of this...

Occurrence and Prognostic Significance of Pseudodissection Phenomenon Associated with Acute Distal Internal Carotid Artery Occlusion (P07.011)

Objective: To determine the angiographic characteristics of the phenomemon of “pseudodissection” and its clinical implications in acute stroke endovascular treatment. Background Acute stroke from intracranial internal carotid artery (ICA) occlusion can occasionally resemble angiographic cervical ICA dissection which may cause delays in endovascular acute stroke treatment. Design/Methods: Retrospective analysis of angiographic and clinical data of 31 patients with acute stroke from ICA occlusion, treated with endovascular therapy at two University affiliated institutions was performed. Pseudodissection was defined as angiographic appearance of typical ICA dissection with evidence of normal inner vascular wall upon further catheter exploration. Results: Angiographic appearance pseudodissection was identified in 7 out of 31 patients (22.6%). Six patients had guide catheters placed proximal to pseudodissection in anticipation of stent placement for treatment of dissection. All 7 patients had further exploration of the presumed dissected segment (6 microcatheter, 1 diagnostic catheter) which demonstrated normal vascular inner wall. The location of the clot was more common in the petro-cavernous segment in the pseudodissection patients (5/7, 71%). Carotid terminus clot was more common in non pseudodissection patients compared to pseduodissection patients (18/24, 75% versus 2/7, 29% respectively, p Conclusions: Early recognition of pseudodissection in the ICA is important in the setting of acute stroke to avoid delay in treatment of intracranial ICA occlusion. Disclosure: Dr. Siddiq has nothing to disclose. Dr. Chaudhry has nothing to disclose. Dr. Anderson has nothing to disclose. Dr. Khatri has nothing to disclose. Dr. Rodriguez has nothing to disclose. Dr. Qureshi has nothing to disclose.

Abstract 3444: Characteristics and Prognostic Significance of Pseudodissection Phenomenon Associated with Acute Distal Internal Carotid Artery Occlusion

Background: Acute stroke from intracranial internal carotid artery (ICA) occlusion can occasionally resemble angiographic cervical ICA dissection which may cause delays in endovascular acute stroke treatment. Objective: To determine the angiographic characteristics of the phenomemon of “pseudodissection” and its clinical implications in acute stroke endovascular treatment. Material and Methods: Retrospective analysis of angiographic and clinical data of 31 patients with acute stroke from ICA occlusion, treated with endovascular therapy at two University affiliated institutions was performed. Pseudodissection was defined as angiographic appearance of typical ICA dissection with evidence of normal inner vascular wall upon further catheter exploration. A cadaver model was then created duplicating intracranial ICA occlusion to demonstrate out hypothesis. Results: Angiographic appearance pseudodissection was identified in 7 out of 31 patients (22.6%). Six patients had guide catheters placed proximal to pseudodissection in anticipation of stent placement for treatment of dissection. All 7 patients had further exploration of the presumed dissected segment (6 microcatheter, 1 diagnostic catheter) which demonstrated normal vascular inner wall. The location of the clot was more common in the petro-cavernous segment in the pseudodissection patients (5/7, 71%). Carotid terminus clot was more common in non pseudodissection patients compared to pseduodissection patients (18/24, 75% versus 2/7, 29% respectively, p &lt; 0.0001). Recanalization was less common in pseudodissection patients compared to non pseudodissection patients (3/7 and 21/24 respectively, p 0.029). We then created a cadaver model with intracranial ICA occlusion at the level of posterior communicating artery to demonstrate the phenomenon of pseudodissection as result of lack of contrast runoff in a closed vessel system. Conclusion: Early recognition of pseudodissection in the ICA is important in the setting of acute stroke to avoid delay in treatment of intracranial ICA occlusion. This phenomenon is probably seen in the setting of distal ICA occlusion which prohibits any fluid transit through the vessel.

The site of embolization related to infarct size, oedema and clinical outcome in a rat stroke model - further translational stroke research

Background and purposeReliable models are essential for translational stroke research to study the pathophysiology of ischaemic stroke in an effort to find therapies that may ultimately reduce oedema, infarction and mortality in the clinic. The purpose of this study was to investigate the relation between the site of arterial embolization and the subsequent oedema, infarction and clinical outcome in a rat embolic stroke model.MethodsThirty-six male Sprague-Dawley rats were thromboembolized into the internal carotid artery. The site of occlusion was demonstrated by arteriography. Following histological preparation and evaluation, the size of the hemispheres and the infarcts were measured by quantitative histology and planimetry. Another parallel stroke model study was subsequently examined to investigate if the conclusions from the first study could be applied to the second study.ResultsThe median size of the infarct was 40% of the ipsilateral hemisphere in both the 19 animals with occlusion localised to the intracranial part of the internal carotid artery and in the 11 animals where the main trunk of the middle cerebral artery was occluded. In 5 animals, occlusion of the extracranial part of the internal carotid artery resulted in significantly smaller infarcts compared to other groups (p < 0.01). Another independent study re-confirmed these results. Furthermore, significant correlations (R > 0.76, p < 0.0001) were found between 1) cortical, subcortical, and total infarct volumes, 2) oedema in percent of the left hemisphere, 3) clinical score before termination and 4) postoperative weight loss.ConclusionsDistal occlusions of the intracranial part of the internal carotid or middle cerebral arteries resulted in comparable large sized infarctions and oedema. This indicates that investigators do not need a similar number of such occlusions in each experimental group. Contrary to observations in the clinic, distal internal carotid artery occlusions did not result in worse outcome than middle cerebral stem occlusions, but this finding may be explained by the controlled emboli size in this experimental stroke model.

Good clinical outcome after ischemic stroke with successful revascularization is time-dependent

Trials of IV recombinant tissue plasminogen activator (rt-PA) have demonstrated that longer times from ischemic stroke symptom onset to initiation of treatment are associated with progressively lower likelihoods of clinical benefit, and likely no benefit beyond 4.5 hours. How the timing of IV rt-PA initiation relates to timing of restoration of blood flow has been unclear. An understanding of the relationship between timing of angiographic reperfusion and clinical outcome is needed to establish time parameters for intraarterial (IA) therapies. The Interventional Management of Stroke pilot trials tested combined IV/IA therapy for moderate-to-severe ischemic strokes within 3 hours from symptom onset. To isolate the effect of time to angiographic reperfusion on clinical outcome, we analyzed only middle cerebral artery and distal internal carotid artery occlusions with successful reperfusion (Thrombolysis in Cerebral Infarction 2-3) during the interventional procedure (<7 hours). Time to angiographic reperfusion was defined as time from stroke onset to procedure termination. Good clinical outcome was defined as modified Rankin Score 0-2 at 3 months. Among the 54 cases, only time to angiographic reperfusion and age independently predicted good clinical outcome after angiographic reperfusion. The probability of good clinical outcome decreased as time to angiographic reperfusion increased (unadjusted p = 0.02, adjusted p = 0.01) and approached that of cases without angiographic reperfusion within 7 hours. We provide evidence that good clinical outcome following angiographically successful reperfusion is significantly time-dependent. At later times, angiographic reperfusion may be associated with a poor risk-benefit ratio in unselected patients.

Accuracy of Conventional plus Transoral Carotid Ultrasonography in Distinguishing Pseudo-Occlusion from Total Occlusion of the Internal Carotid Artery

Background: To investigate the accuracy of conventional carotid ultrasonography (CCU) combined with transoral carotid ultrasonography (TOCU) for distinguishing pseudo-occlusion from total occlusion of the internal carotid artery (ICA). Methods: This study included 95 patients who were suspected of having an occlusion of the ICA on magnetic resonance angiography (MRA) and underwent both CCU and conventional digital subtraction angiography (DSA) in order to confirm the diagnosis. TOCU was also performed to observe the cervical portion of the ICA distal to the stenosis. We compared the ultrasonographic findings with the DSA findings. Results: Twelve of the 95 patients were defined as having an ICA pseudo-occlusion on DSA. On B-mode images with CCU color Doppler, slight residual flow signals in the ICA lumen were shown in 20 patients. Among them, 2 patients had a pulsed Doppler waveform of the distal ICA occlusion pattern. Among the remaining 18 patients, 4 had a pulsed Doppler waveform of the to and fro flow pattern, and 14 had a weak antegrade flow pattern in the ICA lumen. The conventional ultrasonographic method showed 100% sensitivity with 93% specificity for diagnosing an ICA pseudo-occlusion. The addition of TOCU findings increased the specificity to 98%. In 2 patients, who were overdiagnosed as having an ICA pseudo-occlusion even using TOCU, DSA revealed an occlusion of the ICA distal to the ophthalmic artery with a severe stenosis of the proximal ICA. Conclusions: Using conventional and transoral carotid ultrasonography, an ICA pseudo-occlusion can be diagnosed with higher accuracy.