Quantitative magnetic resonance angiography as a potential predictor for cerebral hyperperfusion syndrome: a preliminary study

Development and validation of a nomogram for cerebral hemorrhage in patients with carotid stenosis undergoing stenting: a multicenter retrospective study

BACKGROUND

Hyperperfusion-induced cerebral hemorrhage (HICH) is a rare but severe complication in patients with carotid stenosis undergoing stent placement for which predictive models are lacking. Our objective was to develop a nomogram to predict such risk.

METHODS

We included a total of 1226 patients with carotid stenosis who underwent stenting between June 2015 and December 2022 from three medical centers, divided into a development cohort of 883 patients and a validation cohort of 343 patients. The model used LASSO regression for feature optimization and multivariable logistic regression to develop the predictive model. Model accuracy was assessed via the receiver operating characteristic curve, with further evaluation of calibration and clinical utility through calibration curves and decision curve analysis (DCA). The model underwent internal validation using bootstrapping and external validation with the validation cohort.

RESULTS

Older age (OR 1.07, p=0.005), higher degrees of carotid stenosis (OR 1.07, p=0.006), poor collateral circulation (OR 6.26, p<0.001), elevated preoperative triglyceride levels (OR 1.27, p=0.041) and neutrophil counts (OR 1.36, p<0.001) were identified as independent risk factors for HICH during hospitalization. The nomogram constructed based on these predictive factors demonstrated an area under the curve (AUC) of 0.817. The AUCs for internal and external validation were 0.809 and 0.783, respectively. Calibration curves indicated good model fit, and DCA confirmed substantial clinical net benefit in both cohorts.

CONCLUSION

We developed and validated a nomogram to predict HICH in patients with carotid stenosis post-stenting, facilitating early identification and preventive intervention in high-risk individuals.

Anesthesia care in the interventional neuroradiology suite: an update

PURPOSE OF REVIEW

The scope of procedures conducted by neurointerventionalists is expanding quickly, with lacking consensus over the best anesthesia modality. Although the procedures involve all age groups, the interventions may be complex and lengthy and may be provided in hospitals currently not yet familiar with the field. Here we review current literature addressing elective outpatient neurointerventional procedures and aim to provide an update on the management of intervention-specific crises, address special patient populations, and provide key learning points for everyday use in the neurointerventional radiology suite.

RECENT FINDINGS

Various studies have compared the use of different anesthesia modalities and preinterventional and postinterventional care. Monitored anesthesia care is generally recommended for elderly patients, whereas children are preferably treated with general anesthesia. Additional local anesthesia is beneficial for procedures, such as percutaneous kyphoplasty and vascular access.

SUMMARY

Combining different anesthetic modalities is a valuable approach in the neurointerventional radiology suite. More interventional and patient population-specific studies are needed to improve evidence-based perioperative management.

Prediction of Long-Term Restenosis After Carotid Endarterectomy Using Quantitative Magnetic Resonance Angiography

Background

To detect restenosis after carotid endarterectomy (CEA), long-term monitoring is required. However, non-selective follow-up is controversial and can be limited by costs and logistical considerations.

Objective

To examine the value of immediate perioperative vessel flow measurements after CEA using quantitative magnetic resonance angiography (QMRA) to detect patients at risk of long-term restenosis.

Methods

A prospective cohort study with long-term sonographic follow-up after CEA for symptomatic internal carotid artery stenosis (ICAs) > 50%. In all patients, vessel flow has been assessed both pre- and postoperatively using QMRA within ±3 days of surgery. Data on QMRA assessment were analyzed to identify patients at risk of restenosis for up to 10 years.

Results

Restenosis was recorded in 4 of 24 patients (17%) at a median follow-up of 6.8 ± 2.6 years. None of them experienced an ischemic event. Perioperative flow differences were significantly greater in patients without long-term restenosis, both for the ipsilateral ICA (p < 0.001) and MCA (p = 0.03), compared to those with restenosis (p = 0.22 and p = 0.3, respectively). The ICA mean flow ratio (p = 0.05) tended to be more effective than the MCA ratio in predicting restenosis over the long term (p = 0.35).

Conclusion

Our preliminary findings suggest that QMRA-based mean flow increases after CEA may be predictive of restenosis over the long term. Perioperative QMRA assessment could become an operator-independent screening tool to identify a subgroup of patients at risk for restenosis, in whom long-term monitoring is advised.

Severe cerebral edema induced by watershed shift after bypass in a patient with chronic steno-occlusive disease: a case report and short literature review

Background

Carotid occlusive disease is a type of progressive disease resulting in ischemic stroke. Extracranial-intracranial bypass surgery represents a valid therapeutic option when medical treatment does not make effects. The appearance of cerebral edema following bypass is common during acute stage. Additionally, there are many causes of mild cerebral edema, such as hemodynamic changes, venous congestion and others. However, severe edema involving large brain tissue, which presents as reversible aphasia and hemiplegia, remains to be elucidated.

Case presentation

A 55-year-old man was admitted to the neurosurgery department for repeated dizziness for over a year and sudden onset of syncope 1 month prior, and he was diagnosed with carotid occlusive disease. After surgical contraindications were excluded, dual bypass and encephalo-duro-myo-synangiosis were performed. Although blood pressure and fluid management were strictly under control promptly after surgery, massive cerebral edema involving the left anterior cerebral artery and middle cerebral artery territories occurred from the 6th day after surgery. Additionally, no discernible cerebral infarction or hemorrhage occurred. Moreover, the cerebral blood flow of the middle cerebral artery displayed an early decrease followed by delayed elevation on the left side. Without restricting the spreading of cerebral edema, life-threatening cerebral herniation could develop at any time. Mannitol and furosemide were administered for impending cerebral herniation. The amelioration of symptoms was noticed on the 16th day after surgery. The patient felt relief on the 21st day after surgery. Digital subtraction angiography performed on the 180th day after surgery demonstrated the patency of dual anastomosed vessels, and the patient recovered without any permanent neurological deficit.

Conclusion

Based on changes in cerebral blood flow and reversible symptoms, the “watershed shift” phenomenon could explain such a severe deficit. However, this deficit was not the same as the classical presentation of the “watershed shift”, which involves a moderate amount of brain tissue and presents significant increases in cerebral blood flow. In addition to the “watershed shift”, a swollen temporal muscle may also participate in the progression of focal edema.

Flow evaluation of STA-MCA bypass using quantitative ultrasonography: An alternative to standard angiography for follow up of bypass graft

PURPOSE

To date, digital subtraction angiography (DSA) has been considered as the gold imaging modality for assessing graft patency after extracranial-intracranial bypass. The utility of a noninvasive and quantitative method of assessing graft flow postoperatively was evaluated by using quantitative ultrasonography.

METHOD

All STA-MCA bypass surgery performed over a 5-year period at a single institution were reviewed. Measured by duplex ultrasonography, pre-operative (day1) and post-operative (day1, day7, 3month and 6 month) graft blood flow rates were recorded and analyzed. Results were correlated to Matsushima grade determined by DSA performed within 24 h when ultrasonography was conducted to confirm the graft function.

RESULTS

100 patients with 131 operated hemispheres were included in this study. The mean flow rates in the STA graft on pre-operative day1, post-operative day 1 and 7, at 3- and 6-month postoperatively were 24.1, 106.7, 112.6, 97.4 and 79.7 ml/min respectively. The mean post-operative flow in the STA graft graded as A/B/C were significantly different (168.0 ± 34.8 ml/min, 91.0 ± 15.5, 42.1 ± 17.2 ml/min, respectively, p = 0.000). 124.5 ml/min and 65.5 ml/min are good cut-off value for predicting post-operative graft Matsushima grade. The analysis also showed excellent agreement between ultrasonography and DSA for assessing bypass function (κ = 0.78).

CONCLUSIONS

The patency of the STA grafts can be assessed noninvasively by quantitative ultrasonography, which results are comparable to those of conventional DSA. This, therefore, suggest that quantitative ultrasonography may be an alternative method to standard DSA for serial follow up of STA grafts.

Carotid Revascularization and Its Effect on Cognitive Function: A Prospective Nonrandomized Multicenter Clinical Study

BACKGROUND

There is conflicting data on the effect of carotid revascularization on cognitive function.

OBJECTIVE

To examine cerebral blood flow and cognitive function after carotid revascularization.

METHODS

Patients with unilateral, asymptomatic hemodynamically significant carotid artery stenosis (80% by computed tomography angiography or magnetic resonance angiography) were eligible. Cerebral blood flow was measured preoperatively and 1 month postoperatively using quantitative phase contrast magnetic resonance angiography. Preoperative flow impairment was defined as ipsilateral flow at least 20% less than contralateral flow (ie, an ipsilateral and/or contralateral flow ratio ≤0.8). Significant improvement in blood flow was defined as at least a 0.15 increase in flow ratio from pre- to postoperative. A control group was managed medically. Four cognitive domains were assessed at baseline, 1 month, and 6-12 months postoperatively.

RESULTS

Seventy-five patients were enrolled at 6 sites; 53 carotid endarterectomy, 11 carotid artery stenting, and 11 medical management only controls. Preoperative Trails B scores were similar between groups. Revascularization was associated with significant improvement in executive function (Trials B) while no improvement was observed in controls (P = .007). Of patients with improvement in middle cerebral artery (MCA) flow, 90% had improved Trails B scores compared to 46.5% of patients without MCA flow improvement (P = .01). Greater absolute improvement in mean Trails B scores was observed in patients with MCA flow improvement compared to those without (48 seconds versus 24.7 seconds, P = .001).

CONCLUSIONS

In a cohort of patient with asymptomatic carotid stenosis, improvement in MCA flow following carotid revascularization is associated with improvement in executive functioning.

[Individual preoperative 3D modeling of vascular brain pathology]

The possibility of segmenting three-dimensional objects by DICOM-series is well known and available both on specialized workstations and on personal computers. The technique, however, is relatively rarely used in clinical practice, and we believe that the benefits of preoperative preparation using segmented 3D models are underestimated. The article is devoted to our experience in using segmentation of anatomical structures based on CT and MRI for preoperative preparation for surgical operations performed in neurosurgical departments on patients with vascular pathology. The paper discusses the types and possibilities of segmentation, provides some examples describing the clinical use of the technique.

[Predictors of long-term complications after carotid endarterectomy]

AIM

To analyze the predictors of complications within 3 years after carotid endarterectomy (CEE).

MATERIAL AND METHODS

The study included 1035 patients after CEE for the period 2011-2016. Long-term follow-up period was 42.4±18.6 months (≈ 3.5 years). The endpoints were such unfavorable cardiovascular events as death, myocardial infarction, stroke/transient ischemic attack, redo revascularization. Statistical analysis was carried out by using of Statistica for Windows 8.0 software package (StatSoft Inc., USA). Stepwise logistic regression was applied to identify risk factors of adverse outcomes and death in long-term postoperative period.

RESULTS

Comprehensive analysis of numerous factors (anamnestic, instrumental-diagnostic, surgical) allowed us to identify predictors of long-term unfavorable outcomes in patients with occlusive-stenotic lesions of carotid arteries. Risk factors of long-term complications were SYNTAX score ≥33 (high risk), unstable plaque in the contralateral ICA, occlusion of contralateral ICA, LVEF <39%, ICA cross-clamping >40 min, previous CABG.

CONCLUSION

These data are extremely important and can be used to create prognostic models. The last ones are necessary to determine optimal treatment strategy in patients with occlusive-stenotic lesions of supra-aortic vessels.