Insight into the cerebral hyperperfusion syndrome following carotid endarterectomy from the national Vascular Quality Initiative

Comparative on the effectiveness and safety of different carotid endarterectomy techniques: a single-center Retrospective Study

BACKGROUND

Carotid endarterectomy (CEA) is a surgical procedure that can reduce the risk of stroke in patients with carotid artery stenosis. However, controversy still exists regarding the optimal surgical technique for CEA.

OBJECTIVE

To compare the safety and effectiveness of different techniques.

METHODS

Data on baseline characteristics as well as perioperative and postoperative complications from patients who underwent CEA at the Department of Vascular Surgery, Xuanwu Hospital, Capital Medical University, were retrospectively collected and analyzed.

RESULTS

A total of 262 CEA patients included in study, with a total of 265 CEA operations. The mean age of 69.95 ± 7.29 (range, 44-89) years. 65 (24.5%) patients underwent cCEA, 94 (35.5%) underwent pCEA, and 106 (40.0%) underwent eCEA. The use of shunt (1.9%) and the mean operation time were lower in eCEA group (P < 0.05). eCEA was also associated with a lower incidence of postoperative hypotension, whereas pCEA was associated with a lower incidence of postoperative hypertension (P < 0.05). There was no significant difference in clinical baseline characteristics, occurrence of perioperative complications, and survival whether restenosis-free, asymptomatic or overall.

CONCLUSIONS

This study found that all three surgical methods are equally safe for the treatment of carotid artery stenosis and are effective in preventing stroke.

Comparison Between Conventional and Patch Carotid Endarterectomy: A Single-Center Retrospective Study

OBJECTIVE

To compare perioperative and long-term safety and effectiveness between conventional carotid endarterectomy (cCEA) and patch carotid endarterectomy (pCEA) under current medical conditions.

METHODS

Data on baseline characteristics as well as perioperative and long-term postoperative complications from patients who underwent cCEA or pCEA at the Department of Vascular Surgery, Xuanwu Hospital of Capital Medical University, from 2013 to 2022, were retrospectively collected and analyzed.

RESULTS

A total of 248 CEA patients were included in our study. The majority of patients (87.3%) were male, and mean age was 63.6 ± 7.6 (range, 40-81) years; 104 patients (41.9%) underwent cCEA, while 144 (58.1%) underwent pCEA. Between the cCEA and pCEA groups, there were no significant differences in clinical baseline characteristics, occurrence of perioperative or long-term (median, 42.5 [range, 7 to 120] months) complications, and survival whether restenosis-free, asymptomatic or overall.

CONCLUSIONS

In a single-center experience, conventional and patch CEA approaches appear similarly safe and effective.

Spinal Cord Infarction With Prolonged Femoral Venoarterial Extracorporeal Membrane Oxygenation

OBJECTIVES

There have been sporadic reports of ischemic spinal cord injury (SCI) during venoarterial extracorporeal membrane oxygenation (VA-ECMO) support. The authors observed a troubling pattern of this catastrophic complication and evaluated the potential mechanisms of SCI related to ECMO.

DESIGN

This study was a case series.

SETTING

This study was performed at a single institution in a University setting.

PARTICIPANTS

Patients requiring prolonged VA-ECMO were included.

INTERVENTIONS

No interventions were done. This was an observational study.

MEASUREMENTS AND MAIN RESULTS

Four hypotheses of etiology were considered: (1) hypercoagulable state/thromboembolism, (2) regional hypoxia/hypocarbia, (3) hyperperfusion and spinal cord edema, and (4) mechanical coverage of spinal arteries. The SCI involved the lower thoracic (T7-T12 level) spinal cord to the cauda equina in all patients. Seven out of 132 (5.3%) patients with prolonged VA-ECMO support developed SCI. The median time from ECMO cannulation to SCI was 7 (range: 6-17) days.There was no evidence of embolic SCI or extended regional hypoxia or hypocarbia. A unilateral, internal iliac artery was covered by the arterial cannula in 6/7 86%) patients, but flow into the internal iliac was demonstrated on imaging in all available patients. The median total flow (ECMO + intrinsic cardiac output) was 8.5 L/min (LPM), and indexed flow was 4.1 LPM/m². The median central venous oxygen saturation was 88%, and intracranial pressure was measured at 30 mmHg in one patient, suggestive of hyperperfusion and spinal cord edema.

CONCLUSIONS

An SCI is a serious complication of extended peripheral VA-ECMO support. Its etiology remains uncertain, but the authors' preliminary data suggested that spinal cord edema from hyperperfusion or venous congestion could contribute.

Laser speckle contrast imaging for blood flow monitoring in predicting outcomes after cerebral ischemia-reperfusion injury in mice

BACKGROUND

In the treatment of ischemic cerebral stroke (ICS), most conventional treatments, including carotid endarterectomy and carotid artery stenting, may cause cerebral ischemia-reperfusion injury (CIRI). For treated ICS patients, changes in cerebral blood flow are directly related to brain function. At present, computed tomography perfusion, dynamic susceptibility contrast-enhanced perfusion weighted imaging and magnetic resonance arterial spin labeling perfusion imaging are used to monitor cerebral blood flow, but they still have some limitations. Our study aimed to monitor the changes in cerebral cortical blood flow by laser speckle contrast imaging (LSCI) in CIRI model mice and to propose a new method for predicting outcomes after CIRI. C57BL/6 N mice were used to establish a mouse CIRI model based on a modified thread-occlusion method and divided into a good outcome group and a poor outcome group according to survival within 7 days. The cerebral cortical blood flow of the area supplied by the left middle cerebral artery was monitored by LSCI at baseline (before modeling), 1 h after ischemia, immediately after reperfusion and 24 h after reperfusion. Then, the brains of the mice were removed immediately and stained with hematoxylin and eosin to observe the pathological changes in brain neurons.

RESULTS

The cerebral cortical blood flow in the poor outcome group was obviously reduced compared with that less in the good outcome group at 24 h after reperfusion (180.8 ± 20.9 vs. 113.9 ± 6.4, p = 0.001), and at 24 h after reperfusion, the cerebral cortical blood flow was negatively correlated with the severity of brain tissue injury (p = - 0.710, p = 0.010).

CONCLUSIONS

LSCI can monitor the changes in cerebral cortical blood flow during CIRI in mice and could be used as a feasible method for predicting outcomes after CIRI in mice.

Prediction of risk factors for intraoperative hypotension during general anesthesia undergoing carotid endarterectomy

Objective

Carotid endarterectomy (CEA) has been considered as “gold standard” treatment for patients with significant carotid stenosis Intra-operative hypotension was a risk factor for post-operative complications in patients undergoing CEA. This study aimed to investigate the predictors for intra-operative hypotension during CEA.

Methods

This retrospective study included consecutive patients underwent CEA from June 1, 2020 to May 31, 2021 in the neurosurgery department of Xuanwu Hospital, Capital Medical University. The intraoperative hypotension was defined as blood pressure (BP) of 20% below standard value for longer than 5 min. Univariable and multivariable analyses were performed to identify the prediction of risk factors for intraoperative hypotension.

Results

Overall, 367 patients were included, and 143 (39.0%) patients had hypotension during CEA procedure. Univariate analysis indicated Grade 3 hypertension (P = 0.002), peripheral artery disease (P = 0.006) and shunting (P = 0.049) were associated with occurrence of intraoperative hypotension during CEA procedure. On multivariable analysis, Grade 3 hypertension (P = 0.005), peripheral artery disease (P = 0.009), and shunting (P = 0.034) were all found to be independent predicting factors of hypotension during the CEA process.

Conclusion

Intraoperative hypotension is a dynamic phenomenon may be affected by patients with grade 3 hypertension, peripheral artery disease and intra-operative shunting. It is necessary to pay special attention to these patients, both intraoperatively and postoperatively, to improve the final clinical outcome.

Hybrid surgery versus endovascular intervention for patients with chronic internal carotid artery occlusion: A single-center retrospective study

Objective

Chronic internal carotid artery occlusion (CICAO) can cause transient ischemic attack (TIA) and ischemic stroke. Carotid artery stenting (CAS) with embolic protection devices and hybrid surgery combining carotid endarterectomy and endovascular treatment are effective methods for carotid revascularization. The objective of this study was to evaluate and compare the effect and safety of the two surgical procedures.

Methods

This was a single-center retrospective study. In this study, 44 patients who underwent hybrid surgery and 35 who underwent endovascular intervention (EI) at our center were enrolled consecutively between May 2016 and March 2022. All patients were classified into four groups (A-D), as described by Hasan et al. We recorded and analyzed clinical data, angiographic characteristics, technical success rate, perioperative complications, and follow-up data.

Results

There was no significant difference in baseline characteristics between hybrid surgery group and EI group, except for plasma high density lipoproteins (HDL) levels (median [interquartile range]: hybrid surgery, 0.99 [0.88–1.18] vs. EI, 0.85 [0.78–0.98] mmol/L, P = 0.001). The technical success rate of hybrid surgery was higher than that of EI (37/44 [84.1%] vs. 18/35 [51.4%], P = 0.002; type A: 15/16 [93.8%] vs. 10/11 [90.9%], P = 1.000; type B: 9/10 [90.0%] vs. 5/7 [71.4%], P = 0.537; type C: 12/15 [80.0%] vs. 3/12 [25.0%], P = 0.004; type D: 1/3 [33.3%] vs. 0/5 [0%], P = 0.375). No significant difference was observed in the incidence of perioperative complications between the two procedures (hybrid surgery: 7/44 [15.9%] vs. EI: 6/35 [17.1%], P = 0.883). In addition, there were no significant differences in the rates of stroke and restenosis during follow-up.

Conclusions

For patients with symptomatic CICAO, hybrid surgery may have an advantage over EI in successfully recanalizing occluded segments. There was no significant difference in safety and restenosis between hybrid surgery and EI.

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

OBJECTIVE

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.

METHODS

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, 5 minutes after declamping, and after suturing the skin) over baseline was compared between CHS and non-CHS patients.

RESULTS

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.

CONCLUSIONS

Our results indicate that intraoperative TCD monitoring helps predict CHS after CEA at an early stage.

Uncertainty quantification in cerebral circulation simulations focusing on the collateral flow: Surrogate model approach with machine learning

Collateral circulation in the circle of Willis (CoW), closely associated with disease mechanisms and treatment outcomes, can be effectively investigated using one-dimensional–zero-dimensional hemodynamic simulations. As the entire cardiovascular system is considered in the simulation, it captures the systemic effects of local arterial changes, thus reproducing collateral circulation that reflects biological phenomena. The simulation facilitates rapid assessment of clinically relevant hemodynamic quantities under patient-specific conditions by incorporating clinical data. During patient-specific simulations, the impact of clinical data uncertainty on the simulated quantities should be quantified to obtain reliable results. However, as uncertainty quantification (UQ) is time-consuming and computationally expensive, its implementation in time-sensitive clinical applications is considered impractical. Therefore, we constructed a surrogate model based on machine learning using simulation data. The model accurately predicts the flow rate and pressure in the CoW in a few milliseconds. This reduced computation time enables the UQ execution with 100 000 predictions in a few minutes on a single CPU core and in less than a minute on a GPU. We performed UQ to predict the risk of cerebral hyperperfusion (CH), a life-threatening condition that can occur after carotid artery stenosis surgery if collateral circulation fails to function appropriately. We predicted the statistics of the postoperative flow rate increase in the CoW, which is a measure of CH, considering the uncertainties of arterial diameters, stenosis parameters, and flow rates measured using the patients’ clinical data. A sensitivity analysis was performed to clarify the impact of each uncertain parameter on the flow rate increase. Results indicated that CH occurred when two conditions were satisfied simultaneously: severe stenosis and when arteries of small diameter serve as the collateral pathway to the cerebral artery on the stenosis side. These findings elucidate the biological aspects of cerebral circulation in terms of the relationship between collateral flow and CH.

Anesthetic management of carotid endarterectomy: an update from Italian guidelines

BACKGROUND AND AIMS

In order to systematically review the latest evidence on anesthesia, intraoperative neurologic monitoring, postoperative heparin reversal, and postoperative blood pressure management for carotid endarterectomy. The present review is based on a single chapter of the Italian Health Institute Guidelines for diagnosis and treatment of extracranial carotid stenosis and stroke prevention.

METHODS AND RESULTS

A systematic article review focused on the previously cited topics published between January 2016 and October 2020 has been performed; we looked for both primary and secondary studies in the extensive archive of Medline/PubMed and Cochrane library databases. We selected 14 systematic reviews and meta-analyses, 13 randomized controlled trials, 8 observational studies, and 1 narrative review. Based on this analysis, syntheses of the available evidence were shared and recommendations were indicated complying with the GRADE-SIGN version methodology.

CONCLUSIONS

From this up-to-date analysis, it has emerged that any type of anesthesia and neurological monitoring method is related to a better outcome after carotid endarterectomy. In addition, insufficient evidence was found to justify reversal or no-reversal of heparin at the end of surgery. Furthermore, despite a low evidence level, a suggestion for blood pressure monitoring in the postoperative period was formulated.

Carotid Interventions for Women: The Hazards and Benefits

The goal of the current review is to examine the hazards and benefits of carotid interventions in women and to provide recommendations for the indications for carotid intervention in female patients. Stroke and cerebrovascular disease are prevalent in women. There are inherent biological and other differences in men and women, which affect the manifestations and outcome of stroke, with women experiencing worse disability and higher mortality following ischemic stroke than men. Due to the underrepresentation of female patients in most clinical trials, the ability to make firm but alternative recommendations for women specifically on the management of carotid stenosis is challenging. Although some data suggest that women might have worse periprocedural outcomes as compared to men following all carotid revascularization procedures, there is also an abundance of data to support a similar risk for carotid procedures in men and women, especially with carotid endarterectomy and transcarotid artery revascularization. Therefore, the indications for carotid revascularization are the same in women as they are in men. The choice of a carotid revascularization procedure in women is based upon the same factors as in men and requires careful evaluation of a particular patient's risk profile, anatomic criteria, plaque morphology, and medical comorbidities that might favor one technique over the other. When performing carotid revascularization procedures in women, tailored techniques and procedures to address the small diameter of the female artery are warranted.

Pre-operative Cerebral Small Vessel Disease on MR Imaging Is Associated With Cerebral Hyperperfusion After Carotid Endarterectomy

Objectives: To determine whether pre-operative cerebral small vessel disease is associated with cerebral hyperperfusion (CH) after carotid endarterectomy (CEA). Methods: Seventy-seven patients (mean age of 66 years and 58% male) undergoing CEA for carotid stenosis were investigated using brain MRI before and after surgery. CH was defined as an increase in cerebral blood flow > 100% compared with pre-operative values on arterial spin labeling MR images. The grade or the number of four cerebral small vessel disease markers (white matter hyperintensities, lacunes, perivascular spaces, and cerebral microbleeds) were evaluated based on pre-operative MRI. Cerebral small vessel disease markers were correlated with CH by using multivariate logistic regression analysis. The cutoff values of cerebral small vessel disease markers for predicting CH were assessed by receiver-operating characteristic curve analysis. Results: CH after CEA was observed in 16 patients (20.78%). Logistic regression analysis revealed that white matter hyperintensities (OR 3.09, 95% CI 1.72-5.54; p < 0.001) and lacunes (OR 1.37, 95% CI 1.06-1.76; p = 0.014) were independently associated with post-operative CH. Receiver-operating characteristic curve analysis showed that Fazekas score of white matter hyperintensities ≥3 points [area under the curve (AUC) = 0.84, sensitivity = 81.3%, specificity = 73.8%, positive predictive value (PPV) = 44.8% and negative predictive value (NPV) = 93.8%] and number of lacunes ≥ 2 (AUC = 0.73, sensitivity = 68.8%, specificity = 78.7%, PPV = 45.8% and NPV = 90.6%) were the optimal cutoff values for predicting CH. Conclusion: In patients with carotid stenosis, white matter hyperintensities and lacunes adversely affect CH after CEA. Based on the NPVs, pre-operative MR imaging can help identify patients who are not at risk of CH.

Relevance of Infarct Size, Timing of Surgery, and Peri-operative Management for Non-ischaemic Cerebral Complications After Carotid Endarterectomy

OBJECTIVE

To assess the incidence of post-operative non-ischaemic cerebral complications as a pivotal outcome parameter with respect to size of cerebral infarction, timing of surgery, and peri-operative management in patients with symptomatic carotid stenosis who underwent carotid endarterectomy (CEA).

METHODS

Retrospective analysis of prospectively collected single centre CEA registry data. Consecutive patients with symptomatic carotid stenosis were subjected to standard patch endarterectomy. Brain infarct size was measured from the axial slice of pre-operative computed tomography/magnetic resonance imaging demonstrating the largest infarct dimension and was categorised as large (> 4 cm²), small (≤ 4 cm²), or absent. CEA was performed early (within 14 days) or delayed (15 - 180 days) after the ischaemic event. Peri-operative antiplatelet regimen (none, single, dual) and mean arterial blood pressure during surgery and at post-operative stroke unit monitoring were registered. Non-ischaemic post-operative cerebral complications were recorded comprising haemorrhagic stroke and encephalopathy, i.e., prolonged unconsciousness, delirium, epileptic seizure, or headache.

RESULTS

646 symptomatic patients were enrolled of whom 340 (52.6%) underwent early CEA; 367 patients (56.8%) demonstrated brain infarction corresponding to stenosis induced symptoms which was small in 266 (41.2%) and large in 101 (15.6%). Post-operative non-ischaemic cerebral complications occurred in 12 patients (1.9%; 10 encephalopathies, two haemorrhagic strokes) and were independently associated with large infarcts (adjusted odds ratio [OR] 6.839; 95% confidence interval [CI] 1.699 - 27.534) and median intra-operative mean arterial blood pressure in the upper quartile, i.e., above 120 mmHg (adjusted OR 13.318; 95% CI 2.749 - 64.519). Timing of CEA after the ischaemic event, pre-operative antiplatelet regimen, and post-operative blood pressure were not associated with non-ischaemic cerebral complications.

CONCLUSION

Infarct size and unintended high peri-operative blood pressure may increase the risk of non-ischaemic complications at CEA independently of whether performed early or delayed.

Intraoperative Blood Pressure Lability Carries a Higher Risk of Headache after Carotid Endarterectomy

OBJECTIVES

Cerebral hyper-perfusion (CH) is a rare but potentially devastating complication following carotid endarterectomies (CEA). Its symptoms range from new-onset unilateral headache (HA) to intracranial hemorrhage (ICH). Risk factors of CH in the literature to date have not yet yielded a consensus. This study examines intraoperative and postoperative blood pressure variation as a potential risk factor for HA.

METHODS

A single center retrospective review at a tertiary care center from January 2010 to November 2019 was performed. Inclusion criteria were all patients undergoing carotid endarterectomy for symptomatic or asymptomatic carotid disease. Patients with incomplete charts were excluded. Primary endpoints were new-onset unilateral HA or post-operative ICH. Data on intraoperative and post-operative mean arterial blood pressure (MAP), systolic blood pressure (SBP), the mode of endarterectomy, shunt placement, and contralateral carotid status were collected.

RESULTS

735 patients met inclusion criteria: 430 patients underwent modified eversion CEA (59%) vs 305 patients for patch angioplasty (42%). The incidence of HA was 19% (N= 142) in our total cohort. Of the 19% with HA, 1.5% (N=11) demonstrated no relief with analgesics and strict blood pressure control; non-contrast head computed tomography scans were subsequently performed. One patient (0.1%) had an ipsilateral ICH. Univariate analysis demonstrated that greater intra-operative MAP peak had the highest risk for HA (OR 1.014, 95% CI:1.007,1.022 p=0.0002) followed by intra-operative MAP variability (OR 1.011, 95% CI:1.005,1.018 p=<0.0008) and lastly peak intra-operative SBP (OR 1.01, 95% CI:1.004, 1.015 p=0.0011). An unpaired Student's t-test identified change in intra-operative MAP (p<0.005), change in SBP (p<0.005) as well as peak SBP (p<0.001) were significantly associated with HA. Interestingly, there was no significant difference between post-operative MAP variability and HA (p=0.1). Mode of endarterectomy showed no statistically significant difference in risk for developing HA (OR 1.165, 95% CI 0.801, 1.694; p=0.42).

CONCLUSIONS

Greater intra-operative variability in blood pressures are significantly associated with higher risk of HA. Adhering to stricter intra-operative blood pressure parameters and limiting blood pressure variability may be beneficial at reducing the incidence of CH and its complications.

Influence of Eversion Endarterectomy and Patch Reconstruction on Postoperative Blood Pressure After Carotid Surgery

BACKGROUND

Post carotid blood pressure fluctuation and hypertension (PEH) are associated with increased risk for adverse outcome; there is limited evidence on the impact of eversion endarterectomy (E-CEA) versus conventional endarterectomy with patch closure (C-CEA) on postoperative blood pressure course.

PATIENTS AND METHODS

In this retrospective observational study, 859 consecutive carotid endarterectomy procedures between 2004 and 2014 (C-CEA n = 585 vs. E-CEA n = 274), were evaluated. Pre- and postoperative blood pressure values were recorded from recovery room until third postoperative day and compared between both techniques; influences on the dichotomous target variable "at least one postoperative blood pressure peak", that is need for postoperative vasodilators, were analyzed by a logistic regression model. Influences on postoperative systolic blood pressure were evaluated by a linear mixed effects regression model.

RESULTS

Preoperative baseline blood pressure was not different between both comparison groups. During postoperative course, significantly increased mean systolic blood pressure values in the E-CEA group from recovery room to second postoperative day (recovery room C-CEA: 129.2 mm Hg vs. E-CEA: 136.5 mm Hg; P < 0.001; first postoperative day C-CEA: 132.4 mm Hg vs. E-CEA: 139.3 mm Hg; P = 0.0002; second postoperative day C-CEA: 138.6 mm Hg vs. E-CEA: 143.1 mm Hg; P = 0.023) were observed. No hyperperfusion syndrome was detected as wells as no difference in postoperative complication rate. Frequency of antihypertensive interventions was also elevated in E-CEA group (C-CEA 22.1 % vs. E-CEA 31.8 %; P = 0.003). E-CEA (OR 1.591, 95% CI [1.146; 2.202]; P = 0.005) and presence of preoperatively elevated systolic readings (OR 1.015, 95%CI [1.006;1.024]; P < 0.001) was also associated with increased need for antihypertensive interventions.

CONCLUSION

E-CEA was associated with significantly elevated postoperative blood pressure, compared to C-CEA. C-CEA was associated with postoperative blood pressure decrease; however, no difference as to neurologic and surgical complications was detected between both surgical techniques in clinical practice.

Intraoperative Neurophysiology and Transcranial Doppler for Detection of Cerebral Ischemia and Hyperperfusion During Carotid Endarterectomy

OBJECTIVE

To evaluate and compare efficacy of intraoperative neurophysiological monitoring (IONM) and intraoperative transcranial Doppler (TCD) techniques for identification of hypoperfusion during carotid artery clamp and hyperperfusion after release of occlusion during carotid endarterectomy.

METHODS

This was a retrospective, consecutive case series of 152 patients undergoing carotid endarterectomy between June 2018 and March 2020. Somatosensory evoked potentials, motor evoked potentials, electroencephalogram, and TCD were obtained.

RESULTS

Three patient cohorts were observed after clamping the carotid artery: A, in 132 of 152 patients (87%), TCD blood flow velocity decreased by <50% and there were no changes in IONM; B, in 5 of 152 (3%) patients, TCD blood flow rate was reduced 50%-100% with no changes in IONM; C, in 15 patients (10%), blood flow velocity was reduced by 50%-100% and all IONM modalities met warning criteria. With increased blood pressure, IONM and blood flow velocities improved to less than warning criteria in 8 of 15 patients. In 6 of the 7 remaining patients, IONM modalities recovered to baseline immediately after clamps were removed from the carotid artery. The 1 patient with persistent motor evoked potential deterioration experienced postoperative proximal muscle weakness, which recovered 48 hours later. In 22 patients, TCD detected hyperperfusion at the moment of clamp release.

CONCLUSIONS

TCD blood flow velocity is correlated with motor evoked potential and somatosensory evoked potential amplitude changes after clamping. After declamping, TCD can detect hyperperfusion and help regulate blood pressure to prevent hyperperfusion.

Recanalization of symptomatic chronic internal carotid artery occlusions by hybrid treatment

OBJECTIVE

To evaluate the efficacy and safety of hybrid revascularization by carotid endarterectomy and endovascular intervention in the treatment of chronic internal carotid artery occlusion (ICAO).

METHODS

We performed a retrospective analysis of patients who received hybrid treatment for symptomatic chronic ICAO between December 2016 and December 2018. Fifty-six patients with long-segment ICAO were enrolled and divided into the short duration (1-3 months) and long ICAO duration (>3 months) groups, and their clinical and angiographic data were analyzed.

RESULTS

The mean duration was 106.8 ± 36.1 days from the date of ICAO diagnosis to revascularization. Totally, 10 patients (17.8%, n = 56) in the short duration group while no patients in the long duration group failed recanalization (n = 7). Perioperative complications included intraoperative thromboembolism in 1 (1.8%) patient and subarachnoid hemorrhage in 2 (3.6%) patients. Early phase postoperative hypertension was noted in 11 (19.6%) patients and cervical hemorrhage in 1 (1.8%) patient. No severe neurological deficits occurred. Overall, the 6-month modified Rankin score, Mini-mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) scores in patients with successful recanalization significantly improved versus the baseline (P < 0.05). After successful recanalization, the long duration group demonstrated more stents for revascularization compared with the short duration group (P < 0.05). Five (10.8%) patients had recurrent transient ischemic attack, and 1 (2.2%) patient developed stroke in the successful revascularization group during 6 months of follow-up. ICA restenosis occurred in 5 (8.9%) patients and re-occlusion was noted in 1 (1.8%) patient.

CONCLUSIONS

Hybrid operation may be feasible and effective for patients with symptomatic chronic complete ICAO according to our limited data. The original occlusion site from the carotid bifurcation and the duration of ICAO should be considered as independent indicators for successful recanalization as well as perioperative outcomes.

Hyperperfusion Syndrome and Baroreflex Failure following Carotid Artery Angioplasty and Stenting for Symptomatic Radiation-Associated Carotid Artery Stenosis

Cerebrovascular manifestations of radiotherapy for head and neck cancers are well described. In Southeast Asia, because nasopharyngeal cancer is common, patients with late cerebrovascular consequences are encountered regularly. This case report describes the long-term follow-up of a Chinese male patient with symptomatic severe radiation-associated atherosclerosis, who had carotid artery angioplasty and stenting performed, and the subsequent complications encountered: cerebral hyperperfusion syndrome, baroreflex failure, and progressive carotid artery stenosis.

Perioperative baseline -blockers: An independent protective factor for post-carotid endarterectomy hypertension

OBJECTIVE

Post-carotid endarterectomy hypertension is a well-recognized phenomenon closely related to surgical complications. This study aimed to determine whether different kinds of perioperative antihypertensive drugs had a protective effect on post-carotid endarterectomy hypertension and influence on intraoperative hemodynamics.

METHOD

We retrospectively investigated 102 carotid stenosis patients who underwent conventional endarterectomy with a perioperative baseline antihypertensive regimen. Post-carotid endarterectomy hypertension was defined as a postoperative peak systolic blood pressure ≥160 mmHg and/or a requirement for any additional antihypertensive therapies. We compared the clinical characteristics and types of baseline perioperative antihypertensive drugs between patients with and without post-carotid endarterectomy hypertension and then determined the significant independent effect of antihypertensive drugs on post-carotid endarterectomy hypertension through multivariate regression and detected their influence on intraoperative hypertension (induction-related systolic blood pressure and vasodilators consumption) and hemodynamic depression (intra-arterial systolic blood pressure ≤100 mmHg and/or heart rate ≤50 beats/min). We also investigated adverse events such as stroke, death, myocardial infarction, and cerebral hyperperfusion syndrome during the postoperative hospitalization.

RESULTS

A total of 52/102 (51.0%) patients were defined as having post-carotid endarterectomy hypertension during the first three days postoperative, including eight patients with a postoperative systolic blood pressure that exceeded 160 mmHg at least once, 31 patients requiring postoperative antihypertensive treatment in addition to their baseline regimen, and 13 patients with both. The incidence of stroke/death/myocardial infarction and cerebral hyperperfusion syndrome after conventional endarterectomy during hospitalization were both 1.9%. A significantly increased risk of composite postoperative complications (including cerebral hyperperfusion syndrome, hyperperfusion-related symptoms, transient ischemic attacks, stroke, death, and cardiac complications) was observed in patients with post-carotid endarterectomy hypertension than without (15.4% versus 2.0%, p = 0.032). Patients free of post-carotid endarterectomy hypertension had a higher incidence of perioperative baseline β-blocker use than patients who suffered from post-carotid endarterectomy hypertension (46.0% versus 21%, p = 0.008). In multivariate analysis, β-blocker use was a significant independent protective factor for post-carotid endarterectomy hypertension (OR = 0.356, 95% CI: 0.146-0.886, p = 0.028). Patients taking β-blockers had a lower postoperative peak systolic blood pressure than the β-blocker-naïve population (137.1 ± 12.1 mmHg versus 145.0 ± 11.2 mmHg, p = 0.008), but the postoperative mean systolic blood pressure showed no intergroup difference. However, the incidence of hemodynamic depression during conventional endarterectomy was higher in patients with perioperative β-blocker use than in those without (44.1% versus 25.0%, p = 0.050). The difference in intraoperative hemodynamic depression became more prominent between the β-blocker and non-β-blocker groups (81.8% versus 33.3%, p = 0.014) for whose preoperative baseline heart rate was equal to or lower than 70 beats/min.

CONCLUSION

The perioperative use of β-blockers is a protective factor for post-carotid endarterectomy hypertension and contributes to stabilizing the postoperative peak systolic blood pressure three days after conventional endarterectomy. However, β-blockers might also lead to intraoperative hemodynamic depression, especially for patients with a low baseline heart rate.

A Machine Learning Approach for Predicting Early Phase Postoperative Hypertension in Patients Undergoing Carotid Endarterectomy

BACKGROUND

This study aimed to establish and validate a machine learning-based model for the prediction of early phase postoperative hypertension (EPOH) requiring the administration of intravenous vasodilators after carotid endarterectomy (CEA).

METHODS

Perioperative data from consecutive CEA procedures performed from January 2013 to August 2019 were retrospectively collected. EPOH was defined in post-CEA patients as hypertension involving a systolic blood pressure above 160 mm Hg and requiring the administration of any intravenous vasodilator medications in the first 24 hr after a return to the vascular ward. Gradient boosted regression trees were used to construct the predictive model, and the featured importance scores were generated by using each feature's contribution to each tree in the model. To evaluate the model performance, the area under the receiver operating characteristic curve was used as the main metric. Four-fold stratified cross-validation was performed on the data set, and the average performance of the 4 folds was reported as the final model performance.

RESULTS

A total of 406 CEA operations were performed under general anesthesia. Fifty-three patients (13.1%) met the definition of EPOH. There was no significant difference in the percentage of postoperative stroke/death between patients with and without EPOH during the hospital stay. Patients with EPOH exhibited a higher incidence of postoperative cerebral hyperperfusion syndrome (7.5% vs. 0, P < 0.001), as well as a higher incidence of cerebral hemorrhage (3.8% vs. 0, P < 0.001). The gradient boosted regression trees prediction model achieved an average AUC of 0.77 (95% CI 0.62 to 0.92). When the sensitivity was fixed near 0.90, the model achieved an average specificity of 0.52 (95% CI 0.28 to 0.75).

CONCLUSIONS

We have built the first-ever machine learning-based prediction model for EPOH after CEA. The validation result from our single-center database was very promising. This novel prediction model has the potential to help vascular surgeons identify high-risk patients and reduce related complications more efficiently.

[Carotid endarterectomy in acute period of ischemic stroke]

A review is devoted to carotid endarterectomy for symptomatic carotid stenosis in acute period of ischemic stroke. Patient selection criteria, dates of surgical intervention and perioperative risk were analyzed.

Effects of Vitamin C on the Prevention of Ischemia-Reperfusion Brain Injury: Experimental Study in Rats

Background

Reperfusion syndrome after carotid endarterectomy is a complication associated with cerebrovascular self-regulation in a chronically hypoperfused cerebral hemisphere, leading to severe neurological damage. Vitamin C is an important antioxidant in brain metabolism that has shown some neuroprotective actions.

Objective

To investigate the potential effects of vitamin C on cerebral reperfusion in comparison with placebo (saline) in rats.

Methods

Male Wistar rats were divided into 3 groups: (i) Sham (n = 4), animals exposed to carotid arteries dissection without clamping; (ii) Control (n = 4), animals exposed to carotid arteries dissection without clamping; (ii) Control (n = 4), animals exposed to carotid arteries dissection without clamping; (ii) Control (

Results

Rats treated with vitamin C presented with a similar behavior as compared to the Sham group in all the three tests (p > 0.05), but it was significantly different from controls (p > 0.05), but it was significantly different from controls (p > 0.05), but it was significantly different from controls (

Conclusion

In the present study, vitamin C was associated with behavioral and motor preservation as well as decreased cerebral MDA levels after induced cerebral ischemia in rats.

Clinical outcomes of postcarotid endarterectomy hypertension

OBJECTIVE

The objective of this study was to determine the clinical relevance of postcarotid endarterectomy hypertension (PEH) by investigating the effect of PEH on hospital length of stay (LOS) and by investigating short-term and long-term complications of PEH. In addition, risk factors for PEH were determined.

METHODS

A single-center retrospective cohort study was performed. Demographic, preoperative, intraoperative, and postoperative outcomes of 192 patients undergoing carotid endarterectomy were evaluated. Outcomes were compared between patients with PEH and patients without PEH. PEH was defined as an acute systolic blood pressure (SBP) rise >170 mm Hg or persistent SBP >150 mm Hg on the ward and leading to the consultation of an internist. The overall survival and event-free survival were compared using a Kaplan-Meier analysis and a Cox regression analysis. A multivariate logistic regression analysis was performed to determine risk factors for PEH.

RESULTS

PEH developed in 44 of 192 patients (25%). Preoperative hypertension (SBP >150 mm Hg) was determined to be a risk factor for PEH (odds ratio, 3.3; 95% confidence interval [CI], 1.6-6.9). Hospital LOS was prolonged in patients with PEH compared with patients without PEH (median LOS of 5 days vs 3 days, respectively; P < .001). No difference in the occurrence of ischemic neurologic events or rebleeding during hospitalization was observed (P = .58 and P = .72, respectively). Cardiovascular and ischemic neurologic events during follow-up did not occur more often in patients with PEH than in patients without PEH (P = .46). There was no difference in mortality between the PEH and non-PEH groups (hazard ratio, 1.6; 95% CI, 0.6-4.3). The same applies to the event-free survival (hazard ratio, 0.77; 95% CI, 0.4-1.7). Combined event-free survival for stroke and myocardial infarction was 92% (95% CI, 87%-97%) at 2 years for patients without PEH and 86% (95% CI, 74%-98%) at 2 years for patients with PEH (P = .25). Event-free survival for mortality was 90% (95% CI, 85%-96%) at 2 years for patients without PEH and 94% (95% CI, 86%-100%) at 2 years for patients with PEH (P = .36).

CONCLUSIONS

Patients with PEH had a significant increase in hospital LOS. However, adverse short-term and long-term events did not occur more often in patients with PEH. High preoperative SBP was identified as a risk factor for PEH; no other demographic and clinical variables were associated with PEH.