Hemorrhage at high altitude: impact of sustained hypobaric hypoxia on cerebral blood flow, tissue oxygenation, and tolerance to simulated hemorrhage in humans.

With ascent to high altitude (HA), compensatory increases in cerebral blood flow and oxygen delivery must occur to preserve cerebral metabolism and consciousness. We hypothesized that this compensation in cerebral blood flow and oxygen delivery preserves tolerance to simulated hemorrhage (via lower body negative pressure, LBNP), such that tolerance is similar during sustained exposure to HA vs. low altitude (LA). Healthy humans (4F/4 M) participated in LBNP protocols to presyncope at LA (1130 m) and 5-7 days following ascent to HA (3800 m). Internal carotid artery (ICA) blood flow, cerebral delivery of oxygen (CDO2) through the ICA, and cerebral tissue oxygen saturation (ScO2) were determined. LBNP tolerance was similar between conditions (LA: 1276 ± 304 s vs. HA: 1208 ± 306 s; P = 0.58). Overall, ICA blood flow and CDO2 were elevated at HA vs. LA (P ≤ 0.01) and decreased with LBNP under both conditions (P < 0.0001), but there was no effect of altitude on ScO2 responses (P = 0.59). Thus, sustained exposure to hypobaric hypoxia did not negatively impact tolerance to simulated hemorrhage. These data demonstrate the robustness of compensatory physiological mechanisms that preserve human cerebral blood flow and oxygen delivery during sustained hypoxia, ensuring cerebral tissue metabolism and neuronal function is maintained.

[Functional assessment of internal carotid artery tortuosity in patients with multifocal atherosclerosis]. / Vazhnost' dinamicheskoi funktsional'noi otsenki patologicheskoi izvitosti vnutrennikh sonnykh arterii u bol'nykh s mul'tifokal'nym aterosklerozom.

The review is devoted to diagnosis and treatment of internal carotid artery tortuosity. The authors consider modern classification, epidemiology and diagnostic options using neuroimaging or ultrasound-assisted functional stress tests depending on medical history and complaints. In addition to standard Doppler ultrasound, rotational and orthostatic tests are advisable due to possible changes of local shape and hemodynamic parameters following body position changes, especially in patients with concomitant atherosclerotic stenosis. Thus, a personalized approach is especially important for treatment and diagnostics of internal carotid artery tortuosity.

[Dynamic functional assessment of internal carotid artery tortuosity in patients with multifocal atherosclerosis]. / Dinamicheskaya funktsional'naya otsenka patologicheskikh izvitostei vnutrennikh sonnykh arterii u bol'nykh s mul'tifokal'nym aterosklerozom. Klinicheskii sluchai.

A personalized approach with attention to anamnesis and specific symptoms is necessary in patients with internal carotid artery tortuosity. Neuroimaging (especially before elective surgery) or functional stress tests following ultrasound of supra-aortic vessels may be necessary depending on medical history and complaints. In addition to standard Doppler ultrasound, these patients should undergo rotational and orthostatic transformation tests. We analyze changes in shape and hemodynamic parameters within the tortuosity area in various body positions. This is especially valuable for patients with concomitant carotid artery stenosis. The article presents a clinical case illustrating the importance of such approach.

Risk Factors for and Intraoperative Management of Intolerance to Flow Reversal in TCAR.

BACKGROUND: In patients deemed high risk for carotid endarterectomy (CEA) who are indicated for treatment of carotid artery stenosis (CAS), transcarotid artery revascularization (TCAR) has been demonstrated as a safe and effective alternative to trans-femoral carotid artery stenting (TF-CAS). Compared to CEA, where approx. 12% of patients undergoing awake intervention do not tolerate internal carotid artery (ICA) clamping, only 1-2% of patients were observed to have intolerance to flow reversal during TCAR based on data from the ROADSTER1/2 trials. This study reviewed awake interventions from those trials to assess factors associated with intolerance to flow reversal and review how those cases were managed. METHODS: This is a retrospective review of prospectively collected data from Reverse Flow Used During Carotid Artery Stenting Procedure (ROADSTER) multicenter trial along with the subsequent post-approval (ROADSTER-2) trial. The subset of patients from both trials undergoing awake TCAR was analyzed to compare demographics, procedural details, and anatomic factors between patients who did and did not experience intolerance to reversal of flow to assess for predisposing factors. Patients were deemed intolerant to flow reversal at the discretion of the operator, often related to changes in completion of neurologic tasks, hemodynamic stability, or patient reported symptoms. RESULTS: A total of 103 patients from ROADSTER and 194 patients from ROADSTER-2 underwent TCAR under local/regional anesthesia. Of these, 8 patients had intolerance to flow reversal, though all cases were successfully completed. While intraoperative hemodynamic data was only available for 5 of the 8 intolerant patients, none experienced hypotension. 4 cases were completed under low flow reversal, 3 cases were successfully weaned from low to high flow over several minutes, and 1 case required general anesthesia. No significant association was found between intolerance to flow reversal and comorbidities including diabetes mellitus (DM), hypertension (HTN), hyperlipidemia (HLD), congestive heart failure (CHF), prior MI or angina, pre-op CAS-related symptoms, prior stroke, prior CAS or CEA, prior neck radiation, tandem stenosis, high cervical stenosis, or hostile neck. A trend towards significance was seen with chronic obstructive pulmonary disease (COPD) and contralateral carotid artery occlusion (P = 0.086 and 0.139, respectively). CONCLUSIONS: Despite intolerance to flow reversal, TCAR cases were successfully completed by adjusting reversal-of-flow rate and do not typically require conversion to GETA. While factors contributing to intolerance of flow reversal during TCAR remain poorly understood, this study identified a trend towards significance with an association of preexisting COPD and contralateral carotid artery occlusion. Given the low number of patients who experienced this issue, a larger sample size is required to better elucidate these trends.

Dynamic carotid plaque imaging using ultrasonography.

OBJECTIVE: Dynamic image analysis of carotid plaques has demonstrated that during systole and early diastole, all plaque components will move in the same direction (concordant motion) in some plaques. However, in others, different parts of the plaque will move in different directions (discordant motion). The aim of our study was (1) to determine the prevalence of discordant motion in symptomatic and asymptomatic plaques, (2) to develop a measurement of the severity of discordant motion, and (3) to determine the correlation between the severity of discordant motion and symptom prevalence. METHODS: A total of 200 patients with 204 plaques resulting in 50% to 99% stenosis (112 asymptomatic and 92 symptomatic plaques) had video recordings available of the plaque motion during 10 cardiac cycles. Video tracking was performed using Farneback's method, which relies on frame comparisons. In our study, these were performed at 0.1-second intervals. The maximum angular spread (MAS) of the motion vectors at 10-pixel intervals in the plaque area was measured in degrees. Plaques were classified as concordant (MAS, <70°), moderately discordant (MAS, 70°-120°), and discordant (MAS, >120°). RESULTS: Motion was discordant in 89.1% of the symptomatic plaques but only in 17.9% of asymptomatic plaques (P < .001). The prevalence of symptoms increased with increasing MAS. For a MAS >120°, the hazard ratio for the presence of symptoms was 47.7 (95% confidence interval, 18.1-125.6) compared with the rest of the plaques after adjustment for the degree of stenosis and mean pixel motion. The area under the receiver operating characteristic curve for the prediction of the presence of symptoms using the MAS was 0.876 (95% confidence interval, 0.823-0.929). The use of the median MAS (120°) as a cutoff point classified 86% of the plaques correctly (sensitivity, 81.4%; specificity, 91.2%; positive predictive value, 90.2%; and negative predictive value, 83.0%). CONCLUSIONS: The use of the MAS value to identify asymptomatic plaques at increased risk of developing symptoms and, in particular, stroke should be tested in prospective studies.

Carotid artery duplex velocity criteria might be equivocal after left ventricular assist device implantation.

BACKGROUND: Although conventional angiography remains the reference standard for the grading of carotid stenosis, carotid duplex ultrasound (CDUS) is the most commonly used modality for determining the degree of carotid stenosis. The validity of CDUS findings for patients after left ventricular assist device (LVAD) implantation is questionable, because the velocities are often altered secondary to the continuous flow nature of the devices. METHODS: A retrospective review was performed of all patients who had undergone LVAD implantation from January 2007 to December 2019. All patients who had undergone CDUS before and after LVAD implantation were included. Patients receiving extracorporeal membrane oxygenation, those with unusable carotid imaging studies, and those with internal carotid artery (ICA) occlusion were excluded. The peak systolic velocity (PSV) and end-diastolic velocity (EDV) in the ICA and common carotid artery (CCA) and the ICA/CCA ratios were compared before and after LVAD implantation. RESULTS: A total of 36 patients (mean age 59 years; 30 men; 6 women) had undergone CDUS both before and after LVAD implantation (mean, 647 days between imaging studies). A total of 61 ICAs had met the criteria for inclusion. Before LVAD, 7 carotid arteries (13%) had had >50% carotid stenosis and 53 (87%) had had 0% to 50% stenosis. The mean changes in the velocities after LVAD were as follows. The ICA PSV had decreased by 6.12 ± 4.34 cm/s, and the ICA EDV had increased by 13.44 ± 4.23 cm/s. The CCA PSV had decreased by 17.22 ± 4.95 cm/s, and the CCA EDV had increased by 10.83 ± 2.59 cm/s. The mean ICA/CCA ratio had increased by 0.18 ± 0.05. All the mean changes in velocity were significant (P < .01), except for the ICA PSV (P = .167). Among four patients with known stenosis of 60% to 69%, the degree of increase in the ICA and CCA EDVs (75.8 and 13.3 cm/s, respectively) was significantly greater than that for patients with <50% or no stenosis. Carotid artery laterality did not significantly affect the differences in mean velocity. Centrifugal LVADs resulted in a significantly larger increase in the ICA EDV compared with axial LVADs (26.0 vs 6.3 cm/s; P < .01). CONCLUSIONS: LVADs were associated with significant changes in CCA PSV, ICA and CCA EDV, and ICA/CCA ratios. However, the magnitude of these changes in patients with <50% stenosis was minimal and might not be clinically significant. The LVAD type might only have an effect on EDV measurements in the CCA, and the left and right carotid arteries did not appear to have different degrees of change in velocity. The currently used criteria for determining carotid stenosis might result in an under- or overestimation of carotid stenosis in patients with an LVAD.

Ipsilateral carotid bypass outcomes in hostile neck anatomy.

OBJECTIVE: To determine differences in outcomes among patients undergoing ipsilateral carotid bypass with hostile or normal neck anatomy. METHODS: Single-center retrospective review of all ipsilateral extracranial carotid bypasses performed between 1998 and 2018. RESULTS: Forty-eight patients underwent ipsilateral carotid bypass from the common carotid artery to either the internal carotid artery or carotid bifurcation during the study period. Seven patients were excluded owing to either a lack of follow-up or missing data. The indications for intervention included infected patches, aneurysmal degeneration, symptomatic and asymptomatic stenosis or restenosis, carotid body tumors, neck malignancy, and trauma. In 25 procedures (61%), there was a hostile neck anatomy defined as a prior history of external beam neck irradiation or neck surgery. Among this group, 12 pectoralis muscle flaps were performed for reconstructive coverage. Conduits included polytetrafluorethylene (n = 21), great saphenous vein (n = 9), superficial femoral artery (n = 7) and arterial homograft (n = 4). All superficial femoral artery conduits were used in the hostile neck group (P = .03). The overall mean time of follow-up was 22 months, with all bypasses remaining patent with no significant clinical stenosis. The 30-day ipsilateral stroke and myocardial infarction rates were 4.88% each, all within the hostile neck group, with no 30-day mortalities for the entire cohort. One-third of the muscle flaps were performed in the setting of infected patches (P = .02) with no significant differences in perioperative outcomes with use. The overall median hospital length of stay was significantly increased in patients receiving muscle flap coverage (3.0 vs 7.0 days; P = .04). CONCLUSIONS: In patients with a complex carotid pathology, ipsilateral carotid bypass is an effective solution for carotid reconstruction. Different conduits should be used depending on the indication. Muscle flap coverage should be considered in hostile settings when primary wound closure is not feasible.

Safety and durability of concomitant carotid endarterectomy with carotid-subclavian bypass grafting.

BACKGROUND: Concomitant carotid endarterectomy (CEA; for severe internal carotid artery stenosis) with carotid-subclavian bypass grafting (CSBG; for proximal common carotid artery or subclavian artery occlusion) is rarely used. Only a few studies have been reported. This report analyzed early and late clinical outcomes of the largest study to date of the combined procedures in our institution. METHODS: Electronic medical records of patients who had concomitant CEA with CSBG during three decades were analyzed. Indications for surgery were arm ischemia, neurologic events, and clinical subclavian steal. Early (30 days) perioperative complications (stroke, death, and others) and late complications (stroke, death) were recorded. Kaplan-Meier analysis was used to estimate late graft/CEA primary patency, freedom from stroke, and stroke-free survival rates. Graft patency was determined clinically and confirmed using duplex ultrasound. Outcomes were compared with previously published data on isolated CSBG by the same group. RESULTS: There were 37 combined procedures analyzed. Mean age was 64 years (range, 45-81 years). Indications for surgery were arm ischemia in 12 (32%), hemispheric transient ischemic attack or stroke in 15 (41%), vertebrobasilar insufficiency in 4 (11%), symptomatic subclavian steal in 10 (27%), and asymptomatic common carotid artery occlusion with severe internal carotid artery stenosis in 6 (16%). The 30-day perioperative (stroke and death) rate was 5.4% (one stroke and one death). Immediate symptom relief was noted in 100%, with 2.7% (transient ischemic attack) symptom recurrence. The crude patency rate of both CEA and CSBG was 92%. At 1 year, 2 years, 3 years, 4 years, and 5 years, respectively, primary patency rates were 100%, 96%, 96%, 96%, and 85%; freedom from stroke rates were 97%, 97%, 97%, 97%, and 97%; and stroke-free survival rates were 94%, 94%, 87%, 82%, and 78%. When these outcomes were compared with the isolated CSBG group alone (28 patients), there was no difference in perioperative stroke (2.7% for concomitant CEA/CSBG vs 0% for isolated CSBG), perioperative death (2.7% vs 2.8%), or late patency rates (92% vs 96%). CONCLUSIONS: Concomitant CEA/CSBG is safe and durable. There was no significant difference in perioperative stroke/death or late patency rates compared with isolated CSBG.

Recurrent epistaxis from inflamed granulated tissue and an associated pseudoaneurysm of the internal carotid artery: case report.

BACKGROUND: Chronic inflamed tissue in nasal cavity is a rare complication of transsphenoidal approach (TSA). Inflamed tissue is rich in blood vessels, which can lead to frequent nosebleeds. In addition, chronic inflammation can cause pseudoaneurysm, whose rupture results in massive epistaxis. There have been few reported cases of pseudoaneurysm of ICA occurring more than 10 years after TSA surgery. CASE PRESENTATION: We report a case of a patient who had recurrent epistaxis for over a decade after TSA surgery, and analyzed the causes of the nosebleeds. The aspect of occurrence of the nosebleeds and the result of biopsy and imaging tests suggest that the nosebleeds were due to chronic inflamed tissue and an associated pseudoaneurysm. The rupture of pseudoaneurysm recurred after treatment with stent placement, and brain abscess was developed. After removing the inflamed tissue by endoscopic resection, the patient no longer had recurrence of ruptured pseudoaneurysm or nosebleeds. CONCLUSIONS: In patients with recurrent nosebleeds, the possibility of intranasal inflammation and subsequent pseudoaneurysm should be considered. Therefore, people who consistently have epistaxis after TSA, even if the bleeding is not in large amount, should be actively screened and treated for nasal chronic inflammation.

Internal Carotid Artery Agenesis in a Trauma Patient with Ipsilateral Neck GSWs.

A 38-year-old man presented to the emergency room in the trauma bay for multiple ballistic injuries to the right neck. He was hemodynamically stable, protecting his airway, and neurologically intact. Computed tomography angiography (CTA) revealed absent filling the right internal carotid artery from its origin to the circle of Willis, which was intact, as well as absent petrous carotid canal on the right. The patient was diagnosed with right internal carotid artery (ICA) agenesis and discharged in several days. This report demonstrates the importance of an in-depth knowledge of vascular embryology and anatomy. The patient has agreed to have images and case details published.

Surgery for near occlusion of the internal carotid arteries. A single center experience.

Several experiences have shown the benefits of carotid endarterectomy (CEA) to treat symptomatic acute occlusion of common and internal carotid arteries. Instead, surgery for carotid near occlusion remains controversial. We report successful surgical treatment in three patients with near occluded carotid artery. Doppler ultrasound scan was performed and showed common or internal carotid artery (ICA) near occlusion with controlateral carotid stenosis <50% (NASCET) with distal recanalization supported by collateral arteries of the external carotid artery (ECA) documented by preoperative CT-scan or selected angiography. Cases were treated by CEA of bifurcation and common-internal carotid bypass, using a PTFE graft or with longitudinal CEA and direct reconstruction. Perioperative and three months follow-up were free from new neurological events. In conclusion surgery for carotid near occlusion can be safely and successfully performed in selected cases with distal recanalization.

Asymptomatic Internal Carotid Aneurysm: An Uncommon Disease of the Carotid Arteries.

Despite a low-incidence extracranial carotid artery aneurysm (ECAA) disease has important clinical repercussion that obliges understanding and knowledge of correct treatment. The 2 dominant etiologies are atherosclerotic degeneration and pseudoaneurysm. The natural history of ECAAs is understood. Neck pain, a pulsatile mass and central or peripheral neurological manifestations are the most common symptoms. Recommendations for diagnosis and treatment are not uniform and still under discussion, representing a challenge for clinicians. We discuss a case of 2.5 cm asymptomatic saccular atherosclerotic ECAA treated surgically in light of the most recent literature.

Unusual Presentation of Bilateral Carotid Artery Dissection: The Importance of Reasoning Outside the Box.

A bilateral internal carotid artery dissection presenting with atypical symptoms of cerebral hypoperfusion has been rarely reported, especially in the absence of obvious precipitating factors. A middle-aged woman presented to the emergency department with a 2-day-history of progressive left arm numbness and weakness, confusion, disorientation and clumsiness worsened by upright position. A cerebral hypoperfusion condition was hypothesized and confirmed by a CT angiography, which showed bilateral internal carotid dissection with uncertain etiology. Screening for predisposing conditions to spontaneous carotid arteries dissection was basically negative. Regarding potential precipitating factors, the patient had used an electric olive harvester days before symptoms onset, without any painful sensation or sudden sequelae. Portable harvesters in olive growing transmit vibrations to the hand-arm system but it remains to be elucidated if hand-arm vibrations can be implicated in vessels wall injury and dissection. Bilateral carotid artery dissection is an infrequent and life-threatening condition which can rarely present with non-specific symptoms of cerebral hypoperfusion. The absence of typical symptoms and known precipitating factors can made the diagnosis quite hard to achieve.

Duplex Ultrasound Surveillance after Transcarotid Artery Revascularization (TCAR) in Clinical Practice.

BACKGROUND: To propose a protocol for the routine clinical use of duplex ultrasound (DUS) assessment after transcarotid artery revascularization (TCAR) procedures, with its specific point of vascular access, based on DUS data from routine clinical practice. METHODS: DUS data were retrospectively collected at 2 centers from a total of 97 patients who underwent a TCAR procedure with at least 30-day and up to 12-month follow-up. Peak systolic velocity (PSV), end diastolic velocity (EDV), and the internal carotid artery (ICA)/common carotid artery (CCA) PSV ratio were collected at baseline (≤30 days after the procedure) and compared with subsequent measurements. RESULTS: Baseline data were established within 30 days after the procedure. There were no access site stenoses, pseudoaneurysms, or dissections detected in follow-up. Average hemodynamics measurements at 12 months after the procedure (36% of patients reached this time point to date) were PSV 167 ± 153 cm/sec, EDV 51 ± 55 cm/sec, and ICA/CCA PSV 2.3 ± 1.9. Five patients (5.2%) exhibited velocities indicative of ≥80% in-stent restenosis (ISR) at 12 months after the procedure. Two patients (2.1%) underwent repeat intervention for ISR based on high velocities and before significant clinical consequence. The other 3 patients (3.1%) were asymptomatic and are being managed medically and monitored for neurological symptoms. One intraprocedural stroke (1.0% of total treated) was observed. CONCLUSIONS: This protocol not only illustrates the utility of using the CCA for the arterial access sheath for carotid stenting, but also successfully identifies patients with clinically significant restenosis >80%-99%. A surveillance regimen of baseline at ≤30 days after the procedure, followed by assessment at 6 and 12 months, and yearly thereafter appears to be a safe and effective protocol, based on the data available to date. A PSV >340 cm/sec and ICA/CCA ratio >4.15 is consistent with an 80-99% restenosis after TCAR. Although a small number, this study serves as a starting point for those who perform TCAR to specifically look at the CCA access site to rule out these potential pitfalls which did occur in the early trials.

Alternate Approach to Concomitant Carotid and Coronary Disease: Perioperative IABP Use during Carotid Endarterectomy.

BACKGROUND: Demographics are shifting toward an increasingly older population in the United States; thus, it is imperative that patients with a complex cardiovascular history are approached in a systematic fashion. Currently, there is no clear protocol on how best to manage elderly patients who present with both severe coronary artery disease and symptomatic carotid stenosis. For cardiac patients with severe, asymptomatic, high-grade carotid artery stenosis, there may be even more of a conundrum. Although most centers would tend to manage the asymptomatic carotid stenosis expectantly, it is well known that patients with severe, uncorrected internal carotid artery disease are at an increased risk of experiencing a cerebrovascular accident during coronary artery bypass grafting (CABG). One approach that has been recognized in other settings as a cost-effective strategy to stabilize high-risk elderly patients preoperatively is the use of an intra-aortic balloon pump (IABP). To better understand the best approach to take in these patients with concomitant disease, we analyzed the outcomes of 4 patients who underwent placement of an IABP before carotid endarterectomy (CEA) as a bridge to CABG. METHODS: Between 2017 and 2019, 4 patients presented with multivessel symptomatic coronary artery disease and greater than 90% stenosis of at least one internal carotid artery and underwent either staged or simultaneous CEA and CABG. There was placement of an IABP in all patients before the CEA. Time to CABG ranged from a simultaneous procedure to 23 days after CEA. RESULTS: The only death within 30-day postoperation involved the patient who had CEA and CABG performed simultaneously. None of the surviving patients experienced a myocardial infarction. Two of the 4 patients experienced acute kidney injury after surgery, and one patient developed atrial fibrillation postoperatively. None of the patients experienced a postoperative neurological complication. In addition, there were no access site complications associated with IABP placement. CONCLUSIONS: A staged procedure with placement of an IABP can be successfully used in carefully selected patients presenting with concomitant severe carotid and coronary artery disease who will undergo surgical management of their disease. The stabilization provided by IABP was potentially protective against adverse postoperative events and appeared to allow for flexibility in the time between CEA to CABG for patients. Additional studies are necessary to further understand the impact of such an approach.

Comparison of methods between CT perfusion source images and CT angiography in collateral flow assessment.

BACKGROUND: The methods used for grading leptomeningeal collateral flow (LMF) on single-phase computed tomography angiography (CTA) are heterogeneous and limited by temporal resolution. PURPOSE: To compare the reliability of relative filling time delay (rFTD) on CT perfusion source images (CTP-SI) and the currently used single-phase CTA collateral assessment methods and evaluate their ability to predict clinical outcomes in acute ischemic stroke patients. MATERIAL AND METHODS: We analyzed consecutive middle cerebral artery or internal carotid artery occlusion patients who received multimodal CT before treatment and within 12 h of stroke symptom onset from October 2015 to December 2018. Patients were dichotomized using the 90-day mRS into good (0-1) versus adverse (2-6) outcomes. CTP-SI was used to identify the rFTD score. CTA images were reconstructed to assess collateral status using the collateral score (Cs) and region leptomeningeal collateral score (rLMCs). Two observers independently assessed images. RESULTS: The baseline characteristics (n = 54) were median age of 67 years and 68.5% of the participants were men. The baseline median NIHSS was 14. Good clinical outcomes were observed in 19 (35.2%) patients. The k value was higher for rFTDs (k = 0.779, P < 0.001) than Cs (k = 0.666, P < 0.001) and rLMCs (k = 0.763, P < 0.001). Higher rFTDs were correlated with lower rLMCs (Spearman's rho -0.68, P < 0.001) and Cs (rho -0.66, P < 0.001). In multivariate logistic regression, rFTD was associated with functional outcomes (P = 0.044). CONCLUSION: The rFTDs method is comparable to single-phase CTA-based assessments in assessing LMFs in acute ischemic stroke patients. Higher rFTDs is independently associated with adverse long-term functional outcomes.

Chronic total occlusion and spontaneous recanalization of the internal carotid artery: Natural history and management strategy.

OBJECTIVES: Spontaneous recanalization of a chronic total occlusion of the extra-cranial internal carotid artery is an under-reported clinical entity. This paper reviews the different etiologies of internal carotid artery occlusion, its natural course, as well as the significance and our recommendations for the management of spontaneous internal carotid artery recanalization. METHODS: A review of literature on etiology, diagnosis, and treatment of internal carotid artery occlusion and recanalization was conducted. PubMed database was searched using the terms "internal carotid occlusion" and "recanalization". Articles were reviewed and studies involving the management of internal carotid artery occlusion and spontaneous recanalization were included. We subsequently developed a management algorithm for chronic total occlusion of the internal carotid artery and spontaneous recanalization of such lesions based on the available evidence. RESULTS: Common etiologies of chronic total occlusion of the internal carotid artery include carotid atherosclerotic disease, cardioembolic, and carotid dissection. Progression of an asymptomatic to symptomatic occlusion is estimated at 2-8% annually. Well-compensated patients can be asymptomatic. In others, clinical symptoms range from ipsilateral or global hypoperfusion to embolic stroke in some cases of spontaneous recanalization. Spontaneous recanalization occurs in 2.3-10.3% of patients but rarely results in a cerebrovascular event. CONCLUSIONS: Progression of an asymptomatic chronic total occlusion of the internal carotid artery to symptomatic is infrequent. The management algorithm of chronic total occlusion of the internal carotid artery and spontaneous recanalization of the internal carotid artery must be tailored to the patient based on symptoms, etiology of the lesion, imaging findings, surgical risk, and reliability for follow-up.

Brain Temperature Measured by Magnetic Resonance Spectroscopy to Predict Clinical Outcome in Patients with Infarction.

Acute ischemic stroke is characterized by dynamic changes in metabolism and hemodynamics, which can affect brain temperature. We used proton magnetic resonance (MR) spectroscopy under everyday clinical settings to measure brain temperature in seven patients with internal carotid artery occlusion to explore the relationship between lesion temperature and clinical course. Regions of interest were selected in the infarct area and the corresponding contralateral region. Single-voxel MR spectroscopy was performed using the following parameters: 2000-ms repetition time, 144-ms echo time, and 128 excitations. Brain temperature was calculated from the chemical shift between water and N-acetyl aspartate, choline-containing compounds, or creatine phosphate. Within 48 h of onset, compared with the contralateral region temperature, brain temperature in the ischemic lesion was lower in five patients and higher in two patients. Severe brain swelling occurred subsequently in three of the five patients with lower lesion temperatures, but in neither of the two patients with higher lesion temperatures. The use of proton MR spectroscopy to measure brain temperature in patients with internal carotid artery occlusion may predict brain swelling and subsequent motor deficits, allowing for more effective early surgical intervention. Moreover, our methodology allows for MR spectroscopy to be used in everyday clinical settings.

Clinical Study of Cerebral Ischemia in Moyamoya Disease from the View of Development of the Anterior Choroidal Artery.

OBJECTIVES: The anterior choroidal artery (AchA) is one of the collateral vessels in moyamoya disease (MMD). The incidence of cerebral ischemia in MMD was analyzed through the association between development of the AchA and advancement of MMD stage. MATERIALS AND METHODS: Twelve patients of MMD with cerebral ischemia (infarction; 9 patients, transient ischemic attack; 3 patients) were enrolled. Advancement of MMD was evaluated using Suzuki's stage. The grades in Suzuki's stage were subclassified into a non-progressive stage for grades 1 and 2, and a progressive stage for grades 4 and 5. Dilatation of the AchA was judged as the presence of development of this artery. Development of the AchA was grouped into proximal type and proximal and distal type. RESULTS: Most frequent locations of infarcts were the anterior and parietal lobes in 6 patients each. Development of the AchA was confirmed on the ischemic side in all patients and on the non-ischemic side in 9 patients. Development of the AchA in the progressive stage was limited in the proximal and distal type on both sides. Development of the AchA in the non-progressive stage was the proximal type on the ischemic side. CONCLUSIONS: The cause of cerebral ischemia was possibly associated with inadequate blood supply of the AchA in the non-progressive stage, and the lower blood flow from the internal carotid artery (ICA) in the progressive stage. Disparity between collateral blood flow from the AchA and the blood flow from the ICA was considered to relate to incidence of cerebral ischemia in MMD.

Motor Function and Activities of Daily Living Recovery after Cardiogenic Internal Carotid Artery Infarction: A Retrospective Cohort study.

OBJECTIVES: this study determines recovery in physical activity and activities of daily living in the early stages after cardiogenic internal carotid artery infarction. MATERIALS AND METHODS: this retrospective comfort study compares assessment data for 334 patients: 150 patients had atherosclerotic infarction (67 internal carotid artery, 87 middle cerebral artery) and 180 had cardiogenic infarction (32 internal carotid artery infarction, 148 middle cerebral artery). We used Brunnstrom recovery score, posture assessment scale for stroke, and functional independence measure. RESULTS: on initial assessment, median Brunnstrom recovery for the cardiogenic internal carotid artery infarction group was I-II in the upper limb, I in the finger, I-II in the lower limb, and IV or higher in all other groups. The median Postural Assessment Scale for Stroke score for the cardiogenic internal carotid artery infarction group was 0; all other groups scored 14 or higher. The median Functional Independence Measure for the cardiogenic internal carotid artery infarction group was 18 (maximum of 100) and the median score for other infarct groups was 25-50 (maximum 126), with P < .01. After a month, final assessment results for the cardiogenic internal carotid artery infarction group were much lower than for the other groups. Only both internal carotid artery infarctions were compared. Atherosclerotic infarctions showed recovery across assessments, except understanding, onset, and memory (P < .01), and cardiogenic infarctions did not change from the initial assessment in all criteria assessed. CONCLUSIONS: adapting cardiogenic internal carotid artery infarction as a stroke recovery model is difficult.