22 research outputs found
Association of the 24âHour National Institutes of Health Stroke Scale After Mechanical Thrombectomy With Early and LongâTerm Survival
Background The National Institutes of Health Stroke Scale (NIHSS) obtained 24 hours after ischemic stroke is a good indicator for functional outcome and early mortality, but the correlation with longâterm survival is less clear. We analyzed the correlation of the NIHSS after 24 hours (24h NIHSS) and early clinical neurological development after mechanical thrombectomy with early and longâterm survival as well as its predictive power on survival. Methods We reviewed a prospective observational registry for all patients undergoing mechanical thrombectomy between January 2010 and December 2018. Vital status was extracted from the Swiss Population Registry. Adjusted hazard ratio (aHR) and crude hazard ratios were calculated using Cox regression. To assess predictive power of the 24h NIHSS, different Random Survival Forest models were evaluated. Results We included 957 patients (median followâup 1376 days). Patients with lower 24h NIHSS and major early neurological improvement had substantially better survival rates. We observed significantly higher aHR for death in patients with 24h NIHSS 12 to 15 (aHR, 1.78; 95% CI, 1.1â2.89), with 24h NIHSS 16 to 21 (aHR, 2.54, 95% CI, 1.59â4.06), and with 24h NIHSS >21 (aHR, 5.74; 95% CI, 3.47â9.5). The 24h NIHSS showed the best performance predicting mortality (receiver operating characteristic area under the curve at 3 months [0.85±0.034], at 1 year [0.82±0.029], at 2 years [0.82±0.031], and at 5 years [0.83±0.035]), followed by NIHSS change. Conclusions Patients with acute ischemic stroke achieving a low 24h NIHSS or major early neurological improvement after mechanical thrombectomy had markedly lower longâterm mortality. Furthermore, 24h NIHSS had the best predictive power for early and longâterm survival in our machine learningâbased prediction
Prediction of delayed reperfusion in patients with incomplete reperfusion following thrombectomy.
BACKGROUND
The clinical course of patients with incomplete reperfusion after thrombectomy, defined as an expanded Thrombolysis in Cerebral Infarction (eTICI) score of 2a-2c, is heterogeneous. Patients showing delayed reperfusion (DR) have good clinical outcomes, almost comparable to patients with ad-hoc TICI3 reperfusion. We aimed to develop and internally validate a model that predicts DR occurrence in order to inform physicians about the likelihood of a benign natural disease progression.
PATIENTS AND METHODS
Single-center registry analysis including all consecutive, study-eligible patients admitted between 02/2015 and 12/2021. Preliminary variable selection for the prediction of DR was performed using bootstrapped stepwise backward logistic regression. Interval validation was performed with bootstrapping and the final model was developed using a random forests classification algorithm. Model performance metrics are reported with discrimination, calibration, and clinical decision curves. Primary outcome was concordance statistics as a measure of goodness of fit for the occurrence of DR.
RESULTS
A total of 477 patients (48.8% female, mean age 74 years) were included, of whom 279 (58.5%) showed DR on 24 follow-up. The model's discriminative ability for predicting DR was adequate (C-statistics 0.79 [95% CI: 0.72-0.85]). Variables with strongest association with DR were: atrial fibrillation (aOR 2.06 [95% CI: 1.23-3.49]), Intervention-To-Follow-Up time (aOR 1.06 [95% CI: 1.03-1.10]), eTICI score (aOR 3.49 [95% CI: 2.64-4.73]), and collateral status (aOR 1.33 [95% CI: 1.06-1.68]). At a risk threshold of Râ=â30%, use of the prediction model could potentially reduce the number of additional attempts in one out of four patients who will have spontaneous DR, without missing any patients who do not show spontaneous DR on follow-up.
CONCLUSIONS
The model presented here shows fair predictive accuracy for estimating chances of DR after incomplete thrombectomy. This may inform treating physicians on the chances of a favorable natural disease progression if no further reperfusion attempts are made
Association of Intravenous Thrombolysis with Delayed Reperfusion After Incomplete Mechanical Thrombectomy.
PURPOSE
Treatment of distal vessel occlusions causing incomplete reperfusion after mechanical thrombectomy (MT) is debated. We hypothesized that pretreatment with intravenous thrombolysis (IVT) may facilitate delayed reperfusion (DR) of residual vessel occlusions causing incomplete reperfusion after MT.
METHODS
Retrospective analysis of patients with incomplete reperfusion after MT, defined as extended thrombolysis in cerebral infarction (eTICI) 2a-2c, and available perfusion follow-up imaging at 24âŻÂ±â12âŻh after MT. DR was defined as absence of any perfusion deficit on time-sensitive perfusion maps, indicating the absence of any residual occlusion. The association of IVT with the occurrence of DR was evaluated using a logistic regression analysis adjusted for confounders. Sensitivity analyses based on IVT timing (time between IVT start and the occurrence incomplete reperfusion following MT) were performed.
RESULTS
In 368 included patients (median age 73.7 years, 51.1% female), DR occurred in 225 (61.1%). Atrial fibrillation, higher eTICI grade, better collateral status and longer intervention-to-follow-up time were all associated with DR. IVT did not show an association with the occurrence of DR (aOR 0.80, 95% CI 0.44-1.46, even in time-sensitive strata, aOR 2.28 [95% CI 0.65-9.23] and aOR 1.53 [95% CI 0.52-4.73] for IVT to incomplete reperfusion following MT timing <80 and <100âŻmin, respectively).
CONCLUSION
A DR occurred in 60% of patients with incomplete MT at ~24âŻh and did not seem to occur more often in patients receiving pretreatment IVT. Further research on potential associations of IVT and DR after MT is required
Importance of Delayed Reperfusions in Patients With Incomplete Thrombectomy.
BACKGROUND
There is paucity of data regarding the effects of delayed reperfusion (DR) on clinical outcomes in patients with incomplete reperfusion following mechanical thrombectomy. We hypothesized that DR has a strong association with clinical outcome in patients with incomplete reperfusion after mechanical thrombectomy (expanded Thrombolysis in Cerebral Infarction, 2a-2c).
METHODS
Single-institution's stroke registry retrospective analysis of patients admitted from February 2015 to December 2020. DR was defined as the absence of any perfusion delay on â24-hour contrast-enhanced follow-up perfusion imaging, whereas persistent perfusion deficit denotes a perfusion delay corresponding to the catheter angiographic deficit directly after the intervention. The association of perfusion outcome (DR versus persistent perfusion deficit) with the occurrence of new infarcts and 90-day functional independence (modified Rankin Scale score 0-2) was evaluated using logistic regression analyses. Comparison of predictive accuracy was evaluated by calculating area under the curve for models with and without perfusion outcome.
RESULTS
In 566 patients (mean age 74, 49.6% female), new infarcts in the incomplete reperfusion areas were less common in DR versus persistent perfusion deficit patients (small punctiform: 17.1% versus 25%, large confluent: 7.9% versus 63.2%; P=0.001). After adjustment for confounders, DR was a strong predictor of functional independence (adjusted odds ratio, 2.37 [95% CI 1.34-4.23]). There was a significant improvement in predictive accuracy of functional independence when perfusion outcome was added to expanded Thrombolysis in Cerebral Infarction alone (area under the curve 0.57 versus 0.62, P=0.01).
CONCLUSIONS
Occurrence of DR is closely associated with tissue outcome and functional independence. DR may be an independent prognostic parameter, suggesting it as a potential outcome surrogate for medical rescue therapies
Absence of Susceptibility Vessel Sign in Patients With Malignancy-Related Acute Ischemic Stroke Treated With Mechanical Thrombectomy.
Background and Purpose
Clots rich in platelets and fibrin retrieved from patients with acute ischemic stroke (AIS) have been shown to be independently associated with the absence of the susceptibility vessel sign (SVS) on MRI and active malignancy. This study analyzed the association of SVS and the presence of active malignancy in patients with AIS who underwent mechanical thrombectomy (MT).
Methods
This single-center, retrospective, and cross-sectional study included consecutive patients with AIS with admission MRI treated with MT between January 2010 and December 2018. SVS status was evaluated on susceptibility-weighted imaging. Adjusted odds ratios (aORs) were calculated to determine the association between absent SVS and the presence of active or occult malignancy. The performance of predictive models incorporating and excluding SVS status was compared using areas under the receiver operating characteristics curve (auROC).
Results
Of 577 patients with AIS with assessable SVS status, 40 (6.9%) had a documented active malignancy and 72 (12.5%) showed no SVS. The absence of SVS was associated with active malignancy (aOR 4.85, 95% CI 1.94-12.11) or occult malignancy (aOR 11.42, 95% CI 2.36-55.20). The auROC of predictive models, including demographics and common malignancy biomarkers, was higher but not significant (0.85 vs. 0.81, p = 0.07) when SVS status was included.
Conclusion
Absence of SVS on admission MRI of patients with AIS undergoing MT is associated with malignancy, regardless of whether known or occult. Therefore, the SVS might be helpful in detecting paraneoplastic coagulation disorders and occult malignancy in patients with AIS
Absence of susceptibility vessel sign and hyperdense vessel sign in patients with cancer-related stroke
Background and aimIdentification of paraneoplastic hypercoagulability in stroke patients helps to guide investigations and prevent stroke recurrence. A previous study demonstrated an association between the absence of the susceptibility vessel sign (SVS) on brain MRI and active cancer in patients treated with mechanical thrombectomy. The present study aimed to confirm this finding and assess an association between the absence of the hyperdense vessel sign (HVS) on head CT and active cancer in all stroke patients.MethodsSVS and HVS status on baseline imaging were retrospectively assessed in all consecutive stroke patients treated at a comprehensive stroke center between 2015 and 2020. Active cancer, known at the time of stroke or diagnosed within 1âyear after stroke (occult cancer), was identified. Adjusted odds ratios (aOR) and their 95% confidence interval (CI) for the association between the thrombus imaging characteristics and cancer were calculated using multivariable logistic regression.ResultsOf the 2,256 patients with thrombus imaging characteristics available at baseline, 161 had an active cancer (7.1%), of which 36 were occult at the time of index stroke (1.6% of the total). The absence of SVS was associated with active cancer (aOR 3.14, 95% CI 1.45â6.80). No significance was reached for the subgroup of occult cancer (aOR 3.20, 95% CI 0.73â13.94). No association was found between the absence of HVS and active cancer (aOR 1.07, 95% CI 0.54â2.11).ConclusionThe absence of SVS but not HVS could help to identify paraneoplastic hypercoagulability in stroke patients with active cancer and guide patient care
Novel Cruciform Structures as Model Compounds for Coordination Induced Single Molecule Switches
We have synthesized various molecular cruciforms consisting of two different crossing ĂâŹ-systems and comprising crosswise arranged thiol- and pyridine-anchor groups. With these model compounds we strive towards the investigation of a new switching concept based on the potential dependent coordination of pyridines to gold electrodes in an electrochemical set-up. Integration of these cruciform molecules between both electrodes of a mechanically controlled break junction in a liquid environment gave insight into their single molecule transport properties. These studies allowed individual transport characteristics to be assigned to the bar subunits of the cruciforms but also revealed the remaining experimental challenges to realize the suggested switching concept
Controllability of the Coulomb charging energy in close-packed nanoparticle arrays
We studied the electronic transport properties of metal nanoparticle arrays, particularly focused on the Coulomb charging energy. By comparison, we confirmed that it is more reasonable to estimate the Coulomb charging energy using the activation energy from the temperature-dependent zero-voltage conductance. Based on this, we systematically and comprehensively investigated the parameters that could be used to tune the Coulomb charging energy in nanoparticle arrays. We found that four parameters, including the particle core size, the inter-particle distance, the nearest neighboring number, and the dielectric constant of ligand molecules, could significantly tune the Coulomb charging energy
Electroluminescence from a single nanotube-molecule-nanotube junction
The positioning of single molecules between nanoscale electrodes has allowed their use as functional units in electronic devices. Although the electrical transport in such devices has been widely explored, optical measurements have been restricted to the observation of electroluminescence from nanocrystals and nanoclusters and from molecules in a scanning tunnelling microscope setup. In this Letter, we report the observation of electroluminescence from the core of a rod-like molecule between two metallic single-walled carbon nanotube electrodes forming a rigid solid-state device. We also develop a simple model to explain the onset voltage for electroluminescence. These results suggest new characterization and functional possibilities, and demonstrate the potential of carbon nanotubes for use in molecular electronics