Hyperperfusion Syndrome Research Articles

Hyperperfusion Syndrome After Flow Diverter Implantation for an Aneurysm of the Internal Carotid: a case report

Hyperperfusion Syndrome After Flow Diverter Implantation for an Aneurysm of the Internal Carotid: a case report

The first application of intraoperative mri for analysis of cerebral perfusion in surgical brain revascularization

Effectiveness of surgical revascularization in patients with chronic cerebral ischemia depends on restoration of circulation in the damaged artery. Modern methods do not take into account dynamic changes in cerebral perfusion after extra-intracranial microvascular anastomosis (EICMA) and do not allow timely localizing the areas of persistent perfusion deficit. We propose a new method for determining the tactics of surgical cerebral revascularization based on intraoperative MRI (iMRI) perfusion data. This method provides the earliest information on intraoperative brain reperfusion. To develop the principles of dynamic assessment of cerebral blood flow using intraoperative ASL perfusion during surgical revascularization in patients with chronic cerebral ischemia and to determine the indications for additional anastomoses. Surgical revascularization with intraoperative MRI perfusion was performed in 27 patients between March 2022 and April 2023. There were 10 patients with post-thrombotic occlusion of internal carotid artery, 4 patients with occlusion of middle cerebral artery and 13 patients with moyamoya disease. All patients underwent MRI before surgery. After imposing the first EICMA, all patients underwent ASL perfusion for analysis of residual hypoperfusion zones, signs of local hyperperfusion and indications or contraindications for additional revascularization with the second donor branch. In all cases, iMRI made it possible to determine the tactics of brain revascularization using one or two EICMA. In 17 cases, ASL perfusion confirmed the targeted improvement of cerebral blood flow (CBF) in the entire hemisphere or middle cerebral artery basin. Only one EICMA was imposed in these cases. In 10 cases, a single anastomosis was insufficient for restoration of blood flow. These patients underwent additional revascularization with the second donor branch (35.7%). In all cases, we achieved significant quantitative improvement in CBF and volume of brain tissue with restored blood flow (ASPECTS scale). A single EICMA was followed by increase in CBF and areas of restored blood flow by almost 2 times (22.7±9.6 ml/100 g/min and 4.7±1.8 scores (ASPECTS) before surgery vs. 39.4±16.4 ml/100 g/min and 4.7±1.8 scores after EICMA). In the double EICMA group, these parameters increased by almost 3 times (18±3.1 ml/100 g/min and 3.8±0.9 scores before surgery vs. 57±11.4 ml/100 g/min and 7.7±1.5 scores after double EICMA). All patients had no complications. Neurological status improved immediately after surgery in 9 patients (33.3%), stable postoperative period was observed in 12 cases (44.4%). Six (22.2%) patients had transient neurological deficit associated with hyperperfusion syndrome that regressed within a few days after surgery. There were no persistent ischemic complications. Intraoperative ASL perfusion is an effective and informative tool for determining the degree of restoration of blood flow. We can timely adjust surgical strategy, determine the indications or contraindications for additional revascularization and exclude early ischemic complications using this method.

Carotid artery calcification score is associated with the occurrence of cerebral hyperperfusion syndrome after carotid artery stenting

Carotid artery calcification score is associated with the occurrence of cerebral hyperperfusion syndrome after carotid artery stenting

Complication Rate After Carotid Endarterectomy Comparing Patch Angioplasty and Primary Closure: Long-Term Outcome

Objective: In patients with symptomatic or asymptomatic severe internal carotid artery stenosis, carotid endarterectomy (CEA) has been shown to reduce risk for stroke. The optimal surgical technique remains subject of debate. In the latest European Society of Vascular Surgery (ESVS) guidelines on the management of atherosclerotic carotid disease, routine patching is preferred to routine primary closure. However, there are no RCT’s evaluating selective patching strategies. This follow-up study aimed to assess long term complication rate and restenosis after carotid endarterectomy with selective patching. Methods: Two hundred thirteen consecutive carotid endarterectomies over a 3-year period from January 5th 2011 to December 19th 2013 were prospectively analyzed in a follow-up study over 5 years (mean 4.6, range 3.17-6.17). Patient population consisted of 141 procedures on males and 72 on females with mean age 73 years at the time of surgery (standard deviation (SD) 8.57, range 53-95). There was a follow-up of 89%. Postoperative risk factors were assessed such as hypertension, diabetes mellitus, coronary artery disease and smoking. Postoperative symptoms of cranial nerve injury, transient ischemic events, cerebrovascular events and mortality were evaluated. Duplex ultrasound was performed by a radiologist blinded to the operative technique to evaluate patency of the carotid artery after carotid endarterectomy. Results: Primary closure was used in 110 operations, and patch angioplasty in 103 procedures (Dacron patch). Primary closure was performed when the carotid artery had a diameter above 5 mm, when there was a high carotid bifurcation or when the contralateral carotid artery was occluded. There were no significant differences among groups' baseline characteristics at the time of surgery. Primary closure was performed significantly more in male patients (P= .02). Overall complication rate was 3.76% postoperatively (1.8% after primary closure, 5.8% after patch angioplasty) and after 5 years 5.29% (2.0% after primary closure, 9.1% after patch angioplasty). There are no significant differences in results between the two groups (P= .09 and P= .05). In four cases patients experienced symptoms of cranial nerve damage postoperatively, two in each group. In one of the two cases in each group, the patient fully recovered and the other had persistent complaints (P-value= 1). None of the patients experienced amaurosis fugax during the 5-year follow up period. In five cases a patient had an ipsilateral cerebrovascular thrombosis in the group after patch angioplasty compared to zero in the primary closure group (P-value= .02). In the group of primary closure there was a mortality of 26 patients (23.6%) compared to 26 (25.2%) patients after patch angioplasty (P-value = .70). One was caused by cerebral hyperperfusion syndrome within one month postoperative after patch angioplasty and none were caused by an ipsilateral ischemic stroke. Objective duplex ultrasound showed no significant difference comparing restenosis in both groups (P-value= .43). In twelve cases patients showed a restenosis between 50-70% (6 primary closure and 6 patch angioplasty), none of the patients had high grade restenosis of more than 70%. Patient characteristics did not show a significant effect on long term outcomes. There was a correlation between postoperative use of antihypertensive medication and long-term stroke (P-value= .006), restenosis (P-value= .01) and mortality (P-value= .003). Conclusion: After long-term follow-up we found primary closure and patch angioplasty to be equivalent with respect to complication rate and restenosis when used in selected cases. Best medical treatment and especially the use of antihypertensive medication should be emphasized.

Decreased Cerebral Flow Velocities from General Anesthesia are Not Associated with Cerebral Hyperperfusion Syndrome

Decreased Cerebral Flow Velocities from General Anesthesia are Not Associated with Cerebral Hyperperfusion Syndrome

Prospective observation of neurological symptoms attributable to cerebral hyperfusion syndrome after CEA and CAS

Introduction: Neurological symptoms are considered as most clinically significant symptoms with various pathogenesis, including cerebral hyperperfusion syndrome (CHS) and microembolism, in patients shortly after endarterectomy (CEA) and stenting (CAS) for internal carotid artery stenosis (ICA). Aim: This study aimed to compare the structure of neurological symptoms attributable to CHS after carotid artery revascularization collected retrospectively and prospectively in large patient cohorts. Material and methods: Prospective analysis included 1047 consecutive patients treated with CEA (n = 477) or CSA (n = 570) in a single centre from 2011 to 2015. In 2012 was introduced strict monitoring of pain in patients with headache and blood pressure (BP) and more intensive antihypertensive treatment in patients with an increase in BP post-procedure. The occurrence of neurological symptoms attributable to CHS was compared with a historical, retrospectively analysed less strictly monitored cohort (n = 1386). Results: Neurological symptoms attributed to CHS were observed less frequently in prospectively than retrospectively analysed cohort: 8.3% vs 10.6% (p = 0.03) of CEA and 5.7% vs 8.0% (p = 0.10) of CAS group, respectively. The profile of neurological symptoms was similar in both cohorts. The prospective analysis revealed more episodes of transient bradycardia and/or hypotension in the CAS group (10.4 vs 8.8% and 11.2 vs 9.2%, respectively). Conclusion: The incidence of neurological symptoms attributable to cerebral hyperperfusion syndrome after carotid artery revascularization in short-term observation is similar regardless of the method used. Strict monitoring of BP slightly decreased the prevalence of neurological symptoms after carotid artery revascularization.

Effects of different types of carotid endarterectomy on the course of resistant arterial hypertension.

Analysis of the dynamics of systolic blood pressure (SBP) and the results of various types of carotid endarterectomy (СЕЕ) (classical with plasty of the reconstruction zone with a patch, eversion, formation of a new bifurcation, autoarterial reconstruction, glomus-saving techniques) in patients with resistant arterial hypertension (RAH). The actual cohort, comparative, retrospective, open research for the period from January 2013 to December 2021 includes 1577 patients with significant hemodynamic stenosis of the internal carotid artery Depending on revascularization strategy five groups were formed: Group 1: 18.3% (n = 289) - classical Carotid endarterectomy with plasty of the reconstruction zone with a patch (from diepoxy-treated xenopericardium or synthetic); Group 2: 29.9% (n = 472) - eversional CEE with cut-off of carotid gloomus (CG); Group 3: 6.9% (n = 109) - the formation of a new bifurcation; Group 4: 7.4% (n = 117) - autoarterial reconstruction; Group 5: 37.4% (n = 590) - glomus-saving CEE (1 technique - according to A.N. Kazantsev; two technicians - according to R.A. Vinogradov; three technicians - according to K.A.Antsupov). According to the 24-h blood pressure monitor in the preoperative period, the following degrees of AH were identified: 1° - 5.7% (n = 89); 2° - 64.2% (n = 1013); and 3° - 30.1% (n = 475). In the postoperative period, no significant differences were obtained in the frequency of deaths, myocardial infarction, stroke, hemorrhagic transformation. However, according to the frequency of the combined endpoint (death + myocardial infarction + ischemic stroke + hemorrhagic transformation), the lowest rates were observed in the group of classical carotid endarterectomy with plasty of the reconstruction zone with a patch and glomus-sparing CEE (group 1: 1.03% (n = 3); group 2: 3.6% (n = 17); group 3: 3.67% (n = 4); group 4: 2.56% (n = 3); group 5: 0.5% (n = 3); p = 0.10). This is due to the absence of cases of labile AH and hypertensive crises among patients of groups 1 and 5, which was ensured by the preservation of carotid glomus (CG). As a result, the number of patients with 2 and 3 degrees of hypertension in these groups decreased statistically significantly. The vast majority of patients after these operations achieved a stable target SBP. In groups 2, 3, and 4, there was a statistically significant increase in the number of patients with 2 and 3 degrees of AH, which is associated with excision of the CG. Classical CEE and glomus-sparing CEE techniques make it possible to achieve a stable target SBP level in patients with RAH as a result of CG preservation. Removal or traumatization of the latter during eversional CEE, the formation of a new bifurcation, autoarterial reconstruction is accompanied by the development of labile hypertension, an increase in the degree of hypertension and a high risk of hemorrhagic transformation in the brain. Thus, the most effective and safe types of CEE in the presence of RAH are classical CEE with plasty of the reconstruction zone with a patch and glomus-sparing CEE, accompanied by the lowest incidence of adverse cardiovascular events caused by postoperative hypertensive crisis and hyperperfusion syndrome.

Staged Carotid Artery Stenting for Prevention of Hyperperfusion-Induced Intracerebral Hemorrhage in Patients with Very High-Grade Carotid Stenosis and Poor Collateral Compensation

Hyperperfusion-induced intracerebral hemorrhage (HICH) is a relatively rare but potentially devastating event after carotid artery stenting (CAS). Staged angioplasty (SAP), a 2-stage form of CAS, has been shown to be effective for preventing cerebral hyperperfusion syndrome. The aim of our retrospective single-center studywas to investigate the safety and efficacy of SAP to prevent HICH in patients with very severe carotid stenosis (90%-99%) and poor collateral compensation. Between November 2011 and August 2018, 153 patients presented with severe symptomatic carotid artery stenosis ≥90%; 96 were scheduled to undergo regular CAS, and 57 were scheduled for SAP. High risk of HICH were identified based on severe stenosis degree (90%-99%) and poor collateral compensation, which were determined using digital subtraction angiography and qualitative computed tomography perfusion. Patients' clinical data, procedural details, and occurrence of HICH were compared between regular CAS and SAP groups. Of 57 patients scheduled for SAP, 3 were switched to regular CAS because of intraoperative dissection. The median interval between stages I and II was 8 days (IQR: 4-20 days). One patient who was switched to regular CAS experienced HICH. HICH occurred in 1 patient (1.75%; 1/57) in the SAP group and 12 patients (12.5%; 12/96) in the regular CAS group (odds ratio 0.117, 95% confidence interval 0.014-0.990, P= 0.049). Multivariate analysis showed that SAP was negatively related to cerebral hyperperfusion syndrome (odds ratio 0.117; 95% confidence interval 0.014-0.990; P= 0.049). SAP is an effective treatment for avoiding HICH in patients with carotid preocclusive stenosis (90%-99%) and poor collateral compensation.

Outcomes after superficial temporal artery-middle cerebral artery anastomosis combined with multiple burr hole surgery and dural inversion synangiosis for moyamoya disease in adults.

Several forms of cerebral revascularization have been carried out to treat moyamoya disease, however, the existing methods are accompanied by a variety of complications. In this study, the authors aimed to evaluate the clinical and angiographic outcomes of a new surgical procedure: superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis combined with multiple burr hole (MBH) surgery and dural inversion synangiosis for the treatment of moyamoya disease in adults. Patients treated for moyamoya disease from August 2019 to July 2021 were retrospectively reviewed. Clinical data, including perioperative complications and follow-up outcomes, were noted. Preoperative and postoperative angiograms were compared, and the diameters of the frontal branch of the superficial temporal artery (F-STA), the deep temporal artery (DTA), the distal superficial temporal artery (STA) before the bifurcation and the middle meningeal artery (MMA) were measured on preoperative and postoperative angiograms. Meanwhile, a Matsushima score was assigned from postoperative angiograms. This study included 66 patients (67 hemispheres). During the follow-up period, a median of 18 (IQR, 13-21) months, no stroke or death occurred in any of the patients. The clinical outcomes were excellent in 27 patients (40.9%), good in 34 patients (51.6%), fair in 4 patients (6.0%), and poor in 1 patient (1.5%); the overall rate of favorable clinical outcomes (excellent and good) was 92.5%. The modified Rankin Scale (mRS) score was significantly improved at follow-up (P < 0.001). There were 41 hemispheres imaged by cerebral angiography after the operation, at a median postoperative interval of 9 (IQR, 8-12) months; among them, 34 (82.9%) hemispheres had Matsushima scores of grade A and grade B. The average postoperative diameters in the STA, DTA and MMA were increased significantly in 41 hemispheres at follow-up (P < 0.001). Sixteen (24.2%) patients suffered from perioperative complications, including focal hyperperfusion syndrome (HS) in 8 (12.2%) patients, cerebral infarction in 3 (4.5%) patients (including one case accompanied by wound infection), cerebral hemorrhage in 2 (3.0%) patients, seizures in 2 (3.0%) patients, and subdural effusion in 1 (1.5%) patient. The procedure of STA-MCA anastomosis combined with MBH surgery and dural inversion synangiosis may be a safe and effective treatment for adult patients with moyamoya disease.

Contralateral Cortical Subarachnoid Hemorrhage as a Manifestation of Hyperperfusion Syndrome after Carotid Artery Stenting

Cerebral hyperperfusion syndrome is a rare but serious complication of carotid revascularization, and characterized by ipsilateral headache, hypertension, seizures, and focal neurological deficits. Therefore, treatment strategies are directed towards regulation of blood pressure and limitation of rises in cerebral perfusion to prevent cerebral edema or hemorrhage, especially during several days after carotid endarterctomy or stenting. We report the unique case of a patient who suffered from contralateral cortical subarachnoid hemorrhage after carotid artery stenting, despite of well-controlled blood pressure.

Modified pedicled temporoparietal fascial flap combined revascularization in adult moyamoya angiopathy

Pedicled temporoparietal fascial flaps (TPFF), which are flexible, thin, and highly vascularized, have been tried for the moyamoya angiopathy (MMA) treatment. To reduce postoperative complications and improve prognosis, we performed surgical modification and followed up to observe the efficacy. From February 2018 and June 2022, the clinical data of 31 adult MMA patients who underwent the modified TPFF combined revascularization were collected. The clinical outcomes and complications of the patients were recorded until the cut-off date of follow-up. The primary endpoints were the magnetic resonance perfusion (MRP), modified Rankin Scale (mRS) scores, and Matsushima Grade; the secondary endpoints were the clinical symptom outcome and Postoperative complications. Descriptive statistics and rank sum test to assess the therapeutic effect of the modified TPFF combined revascularization for adult MMA treatment. The clinical symptoms of MMA were alleviated in 26 patients and disappeared in five. In all patients, MRP showed improvement in cerebral perfusion on the operated side, and no deterioration or new cerebral infarction occurred during follow-up. Postoperative digital subtraction angiography (DSA) showed that the anastomotic site was patent, and the MMA collateral was decreased in all patients. Only 1 case (3%) of Matsushima grade C showed poor collateral compensation. The admission mRS score (1.54±0.66) of the ischemic MMA was significantly reduced compared with ≥6 months postoperatively (0.54±0.72, P<0.01). The admission mRS score (0.57±0.53) of the hemorrhagic MMA was reduced compared with ≥6 months postoperatively (0, P<0.05). Postoperative complications included epileptic seizures in 2 cases, a cerebral hyper-perfusion syndrome in 2 cases, intracranial rebleeding in 2 cases, skin necrosis in 1 case, and skin maceration in 1 case. Modified TPFF combined revascularization might be a feasible and safe surgical technique for MMA, but it is still necessary to increase the sample size and extend the follow-up time to evaluate its efficacy. Ischemic MMA may have a more significant prognostic benefit than hemorrhagic MMA by this surgery.

A flow self-regulating superficial temporal artery-middle cerebral artery bypass based on side-to-side anastomosis for adult patients with moyamoya disease.

Side-to-side (S-S) superficial temporal artery-middle cerebral artery (STA-MCA) bypass was reportedly used to treat a special moyamoya disease (MMD) patient with collaterals arising from the donor STA. However, the S-S technique is not routinely performed to date, and its benefits are still unknown for adult MMD. The purpose of this study was to investigate the possibility of routine use of the S-S technique for adult MMD. The authors retrospectively analyzed the clinical data of 50 adult patients (65 hemispheres, including 30 in the end-to-side [E-S] group and 35 in the S-S group) with MMD who underwent STA-MCA bypass. The patient demographic characteristics, clinical courses, technical details, intraoperative blood flow data, postoperative and preoperative relative cerebral blood flow (rCBF) values, modified Rankin Scale (mRS) scores, and short-term revascularization results were compared between the 2 groups. There were no significant differences observed in terms of the baseline characteristics, bypass patency rates, postoperative/preoperative rCBF values, incidence of cerebral hyperperfusion syndrome (CHS), mRS scores, and short-term revascularization results between the 2 groups (all p > 0.05). Intraoperative blood flow analysis showed that the increase of STA flow in the E-S group was significantly higher than that of proximal STA flow in the S-S group (p = 0.008). Although the increases of proximal and distal recipient flow in the E-S group seemed greater than those in the S-S group, the results were not statistically significant (p = 0.086 for proximal flow and p = 0.076 for distal flow). CHS symptoms in the S-S group were milder and with much shorter duration. The follow-up angiographic data of the representative case demonstrated that both frontal and parietal STA branches and the occipital artery participated in postoperative collateralization. S-S anastomosis can achieve comparable clinical effects to standard E-S construction. S-S anastomosis used in adult MMD demonstrated mild CHS symptoms with short duration and had the potential to arouse all scalp arteries as donor sources for revascularization through the intact distal STA branch via flow self-regulation.

Cerebral hyperperfusion syndrome after endovascular stent graft reconstruction for postirradiated carotid blowout syndrome: a case report

Background: Cerebral hyperperfusion syndrome (CHS) is a failure of autoregulation after a revascularization procedure. It has rarely been reported in patients with no pre-existing cerebral hypoperfusion. Case Report: We present a rare case of a patient who underwent stent graft implantation to treat postirradiated carotid blowout syndrome. The patient developed hypertension, focal neurological deficit, and seizures after the procedure; neuroimages revealed ipsilateral cerebral edema, swelling, and increased cerebral perfusion. CHS was diagnosed based on clinical and radiological findings. The patient recovered gradually after receiving supportive care. Conclusion: Owing to the risk of CHS, monitoring for cerebral perfusion and prevention of hypertension is suggested for patients who undergo stent graft placement for postirradiated carotid blowout syndrome.

Perioperative functional imaging after extracranial carotid endarterectomy for the detection of cerebral hyperperfusion syndrome

IntroductionSyngoDynaPBVNeuro® is a tool to perform cerebral blood volume (CBV) measurements intraoperatively by functional imaging producing CT-like images. Aim of this prospective study was to analyze the clinical relevance and benefit of CBV measurement with regard to neurological complications like cerebral hyperfusion syndrome (CHS).MethodsForty-five patients undergoing endarterectomy (CEA) of the internal carotid artery were included; functional imaging with CBV measurement was performed before and after CEA. To evaluate and analyze CBV, six regions of interest (ROI) were identified for all patients with an additional ROI in patients with symptomatic ICA stenosis and previous stroke. The primary endpoint of the study was a perioperative change in CBV measurements. Secondary outcomes were incidence of stroke, TIA, CHS, and perioperative morbidity and mortality.ResultsThirty-day stroke incidence and thirty-day mortality were 0%. Thirty-day morbidity was 6.7%. Two patients from the asymptomatic group suffered from transient neurological symptoms without signs of intracerebral infarction in CT or MR scan, meeting diagnostic criteria for CHS. In 83.3% of ROIs in these patients, an increase of blood volume was detected. Overall, 26.7% patients suffered from unilateral headache as expression of potential CHS. A total of 69.4% of ROIs in patients with postoperative unilateral headache showed an increase when comparing pre- and postoperative CBV measurements.ConclusionThe results show that increased CBV measured by functional imaging is a possible surrogate marker of neurological complications like CHS after CEA. By using intraoperative CBV measurement, the risk of CHS can be estimated early and appropriate therapeutic measures can be applied.

Emergency Superficial Temporal Artery-Middle Cerebral Artery Bypass for Atherosclerotic Ischemic Stroke

Endovascular recanalization is the primary strategy for the treatment of acute embolic stroke. However, atherosclerotic occlusions are often challenging to recanalize, and only medical therapy can be performed. In these cases, even the best medical treatment may not be effective, and the cerebral infarction progressively worsens. We believe that an emergency superficial temporal artery-middle cerebral artery(STA-MCA)bypass could be effective in these situations, after careful case selection. We use the following eligibility criteria: (1)atherosclerotic infarction; (2)cerebral ischemia with blood flow < 70% of the contralateral side; (3)progressively worsening symptoms or widening of the subcortical infarction despite medical treatment; and(4)surgery availability < 72 h from symptom onset. Among the 35 patients who underwent urgent STA-MCA bypass from 2014 to 2020, 27(77.1%)gained gait independence, and the National Institutes of Health Stroke Scale(NIHSS)scores improved from a preoperative median of 8 to 3 at discharge. The modified Rankin score(mRS)improved from a preoperative median of 5 to 2 at discharge. No intracerebral hemorrhages occurred due to hyper-perfusion syndrome. When we match it with other reports, this emergency surgery allows 76-90% of patients with progressive stroke to achieve gait independency.

Intraoperative Transcranial Doppler Monitoring Predicts the Risk of Cerebral Hyperperfusion Syndrome After Carotid Endarterectomy

Cerebral hyperperfusion syndrome (CHS) is a rare but serious complication following carotid endarterectomy (CEA). The aim of this study was to identify intraoperative transcranial Doppler (TCD) hemodynamic predictors of CHS after CEA. Between January 2013 and December 2018, intraoperative TCD monitoring was performed for 969 patients who underwent CEA. The percentage increase in the mean velocity of the middle cerebral artery (MCAV%) at 3 postdeclamping time points (immediately after declamping, 5minutes after declamping, and after suturing the skin) over baseline was compared between CHS and non-CHS patients. CHS was diagnosed in 31 patients (3.2%), including 11 with intracranial hemorrhage. The MCAV% values at the 3 postdeclamping time points over baseline were 177% (81%-275%), 90% (41%-175%), and 107% (55%-191%) in the CHS group, significantly higher than those in the non-CHS group (40% [14%-75%], 15% [1%-36%], and 18% [3%-41%], respectively, all P<0.001). Receiver operating characteristic curve analysis showed that the 3 intraoperative MCAV% parameters all had excellent accuracy in identifying CHS (areas under the curve: 0.854, 0.839, and 0.858, respectively, all P<0.001). The predictive value of the model consisting only of preoperative parameters was significantly increased by adding the intraoperative TCD hemodynamic parameters (area under the curve: 0.747 vs. 0.858, P=0.006). Multivariate analyses identified the intraoperative MCAV% immediately after declamping (odds ratio: 9.840, 95% confidence interval: 2.638-36.696, P<0.001) as an independent predictor of CHS. Our results indicate that intraoperative TCD monitoring helps predict CHS after CEA at an early stage.

Angioplasty and Stenting for Carotid Artery Near-Occlusion

Carotid near-occlusion (CNO) is the type of severe atherosclerotic stenosis of the internal carotid artery (ICA) with or without collapse of the vessel distally to the narrow part. According to the North American Symptomatic Carotid Endarterectomy Trial (NASCET), severity of ICA stenosis highly correlates with the risk of stroke, except for cases of extremely critical stenosis &gt; 94%, where the risk is lower, and, according to recent guidelines, conservative treatment is preferable. This consideration is questionable due to the recent data about early stroke recurrence and worldwide practice. Rapid improvement of endovascular technique during the last decade makes carotid angioplasty and stenting (CAS) a feasible option for the treatment of patients with CNO and is widely reported in the literature. However, in uncertain circumstances, more scientific data are necessary to fulfill the gap in indications, terms and risks of CAS for CNO.&#x0D; The aim. To evaluate the results of the treatment of patients with CNO after CAS.&#x0D; Materials and methods. Three hundred and fifteen patients were surgically treated at Scientific-Practical Center of Endovascular Neuroradiology of the National Academy of Medical Sciences of Ukraine due to ICA stenosis between 2010 and 2020. Among them, 39 (12.4%) patients (11 woman / 28 men (age 57.9±2.1 years) had CNO and underwent CAS at our Center. Patient population, clinical and radiological investigations, procedure compli-cations were investigated. Procedure complications (stroke, hemodynamic depression [HD] and hyperperfusion syndrome [HPS]) were meticulously studied. All the patients had routine ultrasound and clinical check 30 days after the procedure.&#x0D; Results. All the patients with CNO were successfully stented with the improvement of the site of stenosis after CAS, with only minimal residual stenosis in cases of severe HD. We observed two procedural vascular accidents, first patient had transient ischemic attack (TIA) and one had stroke due to middle cerebral artery occlusion after stent placement and further urgent mechanical thrombectomy. The patient had no neurologic decline and was discharged home. We didn’t observe any cases of myocardial infarction (MI) or death in our series during the hospital stay. HD was seen in 13 (33.3%) patients, and mostly resolved after the procedure except for 3 casesthat required prolonged intensive care unit stay. HPS was diagnosed in 2 (5.1%) patients and also didn’t have anyneurologic consequences after supportive care. During 30 days of follow-up, one (2.6%) patient had TIA because of anti-platelets cessation and 1 (2.6%) patient had MI after 1 week since discharge. All control images revealedstents patency without the evidence of critical residual stenosis.&#x0D; Conclusions. CNO remains important diagnostic and therapeutic challenge. Recent data showed high risk ofrecurrent stroke in case of CNO on best medical therapy, especially at an early stage, but it remains a preferred option according to guidelines. Considering worldwide improvement of stroke rates after CAS in patients with symptomatic ICA stenosis, further studies are warranted to evaluate its risk-benefit in case of CNO, especially with full collapse. Our data shows that CAS with careful preoperative diagnosis and planning is an effective procedure for selected patients with CNO.

AB148. SOH22ABS108. Cerebral hyperperfusion syndrome: a case report of a rare but devastating entity

AB148. SOH22ABS108. Cerebral hyperperfusion syndrome: a case report of a rare but devastating entity

Peri-procedural variables and outcomes of long-period hemodynamic instability after carotid artery angioplasty and stenting.

The aim of this study is to identify the peri-procedural risk factors and outcomes of hemodynamic instability (HI) after carotid artery stenting (CAS). A single-center, retrospective study was performed in 168 patients who underwent CAS procedure between September 2017 and September 2020. The presence of HI, as defined by hypertension (systolic blood pressure >160mmHg), hypotension (systolic blood pressure <90mmHg), and/or bradycardia (heart rate <60bpm), was recorded. Long-period HI was defined as persistent HI lasting more than 24h. Patient demographics, comorbidities, peri-procedural variables, and risk factors were recorded. Clinical outcomes including cerebral hyperperfusion syndrome, hemorrhage, transient ischemic attack (TIA), stroke, myocardial infarction, and mortality within 30days of the procedure were evaluated. Logistic regression was used to analyze the independent risk factors of long-period HI following CAS. Among 168 patients (mean age, 68.2 ± 8.3years; 81.5% male), the frequency of post-procedural long-period HI was noted in 42 patients (25.0%). Male was prone to experience HI (odds ratio, 9.156, p = 0.021). Aggressive inflation pressure (>7atm) and 5mm balloon for pre-dilatation were risk factors of long-period HI (OR, 7.372, p = 0.035; OR, 3.527, p = 0.023). Intraoperative peak blood pressure and larger-sized stents remained independent predictors for the development of HI (OR, 1.043, p = 0.027, and OR, 1.973, p = 0.015). Patients with prolonged HI were more likely to suffer TIA and stroke compared to other patients and significant difference was found in the occurrence of TIA (p < 0.05). Non-significance was found in mortality rate and other outcomes. CAS-induced HI occurs in a considerable percentage while several peri-procedural variables are determined as independent predictors to develop long-period HI. Patients with prolonged HI are associated with increased risk of neurologic events and thus standardized intervention as well as management of long-period HI are of critical importance during clinical process.

Carotid Artery Stenting in Patients with Symptomatic and Asymptomatic Stenosis: In-Hospital Clinical Outcomes at a Single Neurovascular Center.

Background: Carotid artery stenting (CAS) is a minimally invasive and proven percutaneous procedure that is widely used to treat patients with symptomatic and asymptomatic carotid artery stenosis. The purpose of this study was to characterize the in-hospital outcomes of symptomatic and asymptomatic patients undergoing CAS at a single neurovascular center. Methods: The study was conducted as a retrospective analysis of 1158 patients (asymptomatic, n = 636; symptomatic, n = 522; male, n = 816; median age, 71 years; NASCET method, 70–99% stenosis, n = 830) who underwent CAS between May 2009 and December 2020. In-hospital neurological outcomes, adverse reactions to iodinated contrast media, acute myocardial infarction, intraprocedural complications, and access-site issues were evaluated. The primary endpoints were disabling stroke (including disabling cerebral hyperperfusion syndrome [CHS]) and all in-hospital deaths. Results: A carotid stent could not be deployed in one patient due to calcified plaques (technical failure rate of 0.09%). Four patients (0.3%) experienced in-hospital, stroke-associated death, while five patients (0.4%) died from non-stroke-related causes. All stroke-associated deaths occurred in the symptomatic group and were due to CHS. The disabling stroke rate was 0.9% overall (n = 10; 0.5% versus 1.3% in asymptomatic versus symptomatic patients, respectively). Nineteen patients (1.6%) reached the in-hospital primary endpoint. More patients in the symptomatic group achieved this endpoint than in the asymptomatic group (2.5% versus 0.9%, respectively; p = 0.060). Conclusions: An evaluation was conducted on the in-hospital outcomes of 1158 patients at a single center who underwent CAS and was performed by trained physicians who were supervised by a senior neurovascular interventionist with over 20 years of experience, confirming the excellent safety profile of this procedure with a low rate of complications.