Mapping of Capsular Side Effects by using Intraoperative Motor-Evoked Potentials during Asleep Deep Brain Stimulation Surgery of the Subthalamic Nucleus for Parkinson's Disease.

INTRODUCTION: The aim of this study was to present a novel technique for subthalamic nucleus (STN) deep brain stimulation (DBS) implantation under general anesthesia by using intraoperative motor-evoked potentials (MEPs) through direct lead stimulation and determining their correlation to the thresholds of postoperative stimulation-induced side effects. METHODS: This study included 22 consecutive patients with advanced Parkinson's disease who underwent surgery in our institution between January 2021 and September 2023. All patients underwent bilateral implantation in the STN (44 leads) under general anesthesia without microelectrode recordings (MERs) by using MEPs with electrostimulation directly through the DBS lead. No cortical stimulation was performed during this process. Intraoperative fluoroscopic guidance and immediate postoperative computed tomography were used to verify the electrode's position. The lowest MEP thresholds were recorded and were correlated to the postoperative stimulation-induced side-effect threshold. The predictive values of the MEPs were analyzed. Five DBS leads were repositioned intraoperatively due to the MEP results. RESULTS: A moderately strong positive correlation was found between the MEP threshold and the capsular side-effect threshold (RS = 0.425, 95% CI, 0.17-0.67, p = 0.004). The highest sensitivity and specificity for predicting a side-effect threshold of 5 mA were found to be at 2.4 mA MEP threshold (sensitivity 97%, specificity 87.5%, positive predictive value 97%, and negative predictive value 87.5%). We also found high sensitivity and specificity (100%) at 1.15 mA MEP threshold and 3 mA side-effect threshold. Out of the total 44 leads, 5 (11.3%) leads were repositioned intraoperatively due to MEP thresholds lower than 1 mA (4 leads) or higher than 5 mA (1 lead). The mean accuracy on postoperative CT was 1.05 mm, and there were no postoperative side-effects under 2.8 mA. CONCLUSION: Intraoperative MEPs with electrostimulation directly through the contacts of the DBS lead correlate with the stimulation-induced capsular side effects. The lead reposition based on intraoperative MEP may enlarge the therapeutic window of DBS stimulation.

Plaque characteristics of asymptomatic carotid stenosis and risk of stroke.

BACKGROUND: The optimal treatment of asymptomatic carotid stenosis (ACS) is controversial. To optimize the risk-benefit ratio of carotid artery revascularization, it is crucial to identify ACS patients who are at increased stroke risk. Recent data suggest that plaque vulnerability depends on its composition. Therefore, we assessed plaque composition in ACS to determine predictors for ipsilateral cerebrovascular events. METHODS: 62 patients with 65 ACS ≥50% underwent 3-T MRI of the carotid bifurcation (TOF, special dark-blood weighted noncontrast and contrast-enhanced T(1) and T(2) images) and of the brain. The different plaque components (lipid core, intraplaque hemorrhage, calcification and the status of the fibrous cap) were assessed. Furthermore, the plaque volume and the volume of clinically silent cortical and subcortical infarcts in the territory of the stenosed carotid artery as seen on FLAIR images were determined by using a semi-automated software. Carotid stenosis was considered asymptomatic if there had not been any clinically apparent ischemic events in the corresponding vascular territory within the previous 6 months. During follow-up, information on the occurrence of cerebrovascular events, medical treatment and sonographic changes of the stenosis was collected. RESULTS: At baseline, 24 ACS (37%) were classified as high grade. A lipid-rich necrotic core was the dominant plaque component in 16 ACS (25%). The plaque volume was higher in ACS with a lipid-rich necrotic core as dominant plaque component (p = 0.002) and in patients with prior stroke/TIA (p = 0.010). After a median follow-up of 18.9 months (interquartile range 3.5-30.1) there were 2 ipsilateral strokes and 3 ipsilateral TIAs. The average annual event rate was 7.7%. A lipid-rich necrotic core (HR 7.21; 95% CI 1.12-46.28; p = 0.037), sonographic progression of the stenosis (HR 7.00; 95% CI 1.13-41.34; p = 0.036), history of stroke (HR 11.03; 95% CI 1.23-99.36; p = 0.032), and the volume of clinically asymptomatic ischemic brain lesions (HR 1.14/cm(3); 95% CI 1.03-1.25; p = 0.008) predicted cerebrovascular events. Patients on statin therapy at follow-up were at lower risk of events (HR 0.17; 95% CI 0.03-1.00; p = 0.05). CONCLUSIONS: In addition to medical history and sonographic findings, a lipid-rich necrotic core within the plaque turned out as a predictor of cerebrovascular events. Therefore, MR imaging of carotid plaques deserves further attention and might be helpful to improve risk stratification of asymptomatic carotid disease. The identified predictors could be combined in a risk model and tested in larger prospective studies.

Posterior versus anterior circulation strokes: comparison of clinical, radiological and outcome characteristics.

BACKGROUND AND PURPOSE: Physicians treating patients with posterior circulation strokes (PCS) tended to debate more on whether or not to introduce anticoagulation rather than performing investigations to identify stroke aetiology, as in patients with anterior circulation strokes (ACS). Recent findings suggest that stroke aetiologies of PCS and ACS are more alike than dissimilar, suggesting that PCS deserve the same investigations as ACS. The characteristics and current diagnostic evaluation between patients with PCS and ACS were compared. METHODS: 312 consecutive patients with first ever ACS and 93 patients with first ever PCS were prospectively analysed. RESULTS: Patients with ACS and PCS did not differ in terms of demographic characteristics, prevalence of vascular risk factors, diagnostic evaluation or stroke aetiology. The median National Institutes of Health Stroke Scale score was 8 in ACS and 4 in PCS (p=0.004). Brain imaging revealed more often pathological findings in ACS than PCS. The proportion of non-thrombolysed patients with a favourable clinical outcome (modified Rankin score 0-2) was similar in ACS and PCS (67.0% vs 78.4%; p=0.08). In non-thrombolysed patients, stroke severity was an independent predictor of clinical outcome both in ACS (OR 1.60, 95% CI 1.2 to 2.1; p<0.0001) and in PCS (OR 1.22, 95% CI 1.03 to 1.44; p=0.02) while age predicted poor outcome only in ACS (OR 1.11, 95% CI 1.01 to 1.22; p=0.007). In thrombolysed patients, stroke severity was the only outcome predictor in ACS (OR 1.14, 95% CI 1.04 to 1.25; p=0.004) while we identified no statistically relevant predictor of PCS outcome. CONCLUSIONS: In PCS and ACS, baseline variables, aetiology and outcome are more alike than different.

Diffusion-weighted MRI helps predict outcome in basilar artery occlusion patients treated with intra-arterial thrombolysis.

BACKGROUND: Intra-arterial thrombolysis (IAT) can improve clinical outcome in patients with acute basilar artery occlusion (BAO). The purpose of this study was to determine whether the severity of neurological symptoms, the extent of early ischemic damage on pretreatment diffusion-weighted MRI (DWI), and the lesion progression or regression on post-treatment MRI can predict functional outcome in patients with BAO treated with IAT. METHODS: Thirty-six BAO patients (13 women, 23 men; mean age 60 years) treated with IAT within 12 h of symptom onset were studied. Early ischemic damage on DWI was assessed by applying 4 DWI scoring systems, including a proposed DWI score developed for this study. The latter was used for evaluation of lesion dynamics on post-treatment MRI. The association of pretreatment DWI, severity of symptoms (National Institutes of Health Stroke Scale, NIHSS, and Glasgow Coma Scale, GCS, scores), vessel recanalization, and lesion progression or regression after IAT with clinical outcome at 3 months was analyzed. RESULTS: Median NIHSS and GCS scores on admission were 17 and 10, respectively. In univariate analysis, NIHSS and GCS scores (on admission) and all 4 DWI scores were significantly associated with clinical outcome. After regression analysis for each DWI score, the DWI score proposed herein was the only score that remained independently associated with clinical outcome at 3 months (p = 0.004). A decrease in DWI score was observed in 3 of 23 patients with post-IAT MRI. Successful recanalization was significantly associated with lesion regression (p = 0.044). CONCLUSIONS: BAO patients with less extensive tissue damage on DWI and milder neurological deficits (lower NIHSS and higher GCS) have a better clinical outcome following IAT. The introduced DWI score reliably quantified the pretreatment ischemic damage and was an independent predictor of functional outcome. Lesion regression on DWI score after IAT was associated with vessel recanalization (p = 0.44), but had no impact on clinical outcome.

Long-term outcome of symptomatic severe ostial vertebral artery stenosis (OVAS).

INTRODUCTION: The optimal management of patients with symptomatic severe ostial vertebral artery stenosis (OVAS) is currently unclear. We analyzed the long-term outcome of consecutive patients with OVAS who received either medical treatment (MT) or vertebral artery stenting (VAS). METHODS: Thirty-nine (>70%) patients with severe OVAS were followed for a mean period of 2.8 years. The decision for VAS (n = 10) or MT (n = 29) was left to the clinician. The Kaplan-Meier method was used to assess the risk of recurrent stroke, transient ischemic attack (TIA), or death over the study period. RESULTS: Patients in the VAS group were significantly younger and more likely to have bilateral VA disease (P = 0.04 and P = 0.02). VAS was successfully performed in all ten patients. The periprocedural risk within 30 days was 10% (one TIA). The overall restenosis rate was 10%. One restenosis occurred after 9 months in a patient treated with bare-metal stent. At 4 years of follow-up, VAS showed a nonsignificant trend toward a lower risk for the combined endpoint of TIA and stroke in posterior circulation compared to medical treatment (10% vs. 45%, P = 0.095; relative risk (RR) = 0.24, 95% confidence interval (CI) 0.031-1.85). Patients with bilateral VA disease had a significantly lower recurrence risk after VAS compared with medical treatment (0% vs. 91% at 4 years, P = 0.004; RR 0.10, 95% CI 0.022-0.49) CONCLUSION: VAS was performed without permanent complications in this small series of patients with symptomatic severe OVAS. The long-term benefit seems to be confined to patients with bilateral but not to those with unilateral VA disease.

Predictors of early mortality after acute ischaemic stroke.

BACKGROUND: The study set out to identify clinical, laboratory and radiological predictors of early mortality after an acute ischaemic stroke (AIS) and to analyse medical and neurological complications that caused death. METHODS: A total of 479 consecutive patients (mean age 63+/-14 years) with AIS underwent stroke examination and treatment. Examination included clinical evaluation, laboratory tests, and brain CT and/or MRI. Follow-up data at 30 days were available for 467 patients (93%) who were included in the present analysis. RESULTS: The median National Institute of Health Stroke Study (NIHSS) score on admission was 6. A total of 62 patients (13%) died within 30 days. The cause of death was the initial event in 43 (69%), pneumonia in 12 (19%), intracerebral haemorrhage in 9 (15%), recurrent stroke in 6 (10%), myocardial infarction in 2 (3%), and cancer in 1 (2%) of the patients. In univariate comparisons, advanced age (p<0.001), hypertension (p=0.013), coronary disease (p=0.001), NIHSS score (p<0.001), undetermined stroke etiology (p=0.031), relevant co-morbidities (p=0.008), hyperglycemia (p<0.001), atrial fibrillation (p<0.001), early CT signs of ischemia (p<0.001), dense artery sign (p<0.001), proximal vessel occlusion (p<0.001), and thrombolysis (p=0.008) were associated with early mortality. In multivariate analysis, advanced age (HR=1.12; 95% CI 1.05-1.19; p<0.001) and high NIHSS score on admission (HR=1.15, 95% CI 1.05-1.25; p=0.002) were independent predictors of early mortality. CONCLUSIONS: We report 13% mortality at 30 days after AIS. More than two thirds of the deaths are related to the initial stroke. Advanced age and high NIHSS score are the only independent predictors of early mortality in this series.