Clot Burden Score and Collateral Status and Their Impact on Functional Outcome in Acute Ischemic Stroke

BACKGROUND AND PURPOSE:Collateral status and thrombus length have been independently associated with functional outcome in patients with acute ischemic stroke. It has been suggested that thrombus length would influence functional outcome via interaction with the collateral circulation. We investigated the individual and combined effects of thrombus length assessed by the clot burden score and collateral status assessed by a FLAIR vascular hyperintensity–ASPECTS rating system on functional outcome (mRS).MATERIALS AND METHODS:Patients with anterior circulation acute ischemic stroke due to large-vessel occlusion from the ASTER and THRACE trials treated with endovascular thrombectomy were pooled. The clot burden score and FLAIR vascular hyperintensity score were determined on MR imaging obtained before endovascular thrombectomy. Favorable outcome was defined as an mRS score of 0–2 at 90 days. Association of the clot burden score and the FLAIR vascular hyperintensity score with favorable outcome (individual effect and interaction) was examined using logistic regression models.RESULTS:Of the 326 patients treated by endovascular thrombectomy with both the clot burden score and FLAIR vascular hyperintensity assessment, favorable outcome was observed in 165 (51%). The rate of favorable outcome increased with clot burden score (smaller clots) and FLAIR vascular hyperintensity (better collaterals) values. The association between clot burden score and functional outcome was significantly modified by the FLAIR vascular hyperintensity score, and this association was stronger in patients with good collaterals, with an adjusted OR = 6.15 (95% CI, 1.03–36.81).CONCLUSIONS:The association between the clot burden score and functional outcome varied for different collateral scores. The FLAIR vascular hyperintensity score might be a valuable prognostic factor, especially when contrast-based vascular imaging is not available.

Therapeutic reperfusion with endovascular thrombectomy (EVT) is consistently associated with a better long-term functional outcome in anterior circulation acute ischemic stroke (AIS).¹ Early reperfusion is the mainstay of therapy because it strongly predicts functional outcome.² Many factors impact clinical outcomes, including the extent of clot and collateral supply.^3–7The clot burden score (CBS) assessed by the T2* MR imaging sequence (T2*-CBS), which was adapted from the CTA-CBS,⁸ has been used to assess the extent of the clot⁹ and has been independently associated with functional outcome in patients undergoing EVT.¹⁰Good collaterals have been related to better clinical outcome through 2 distinct mechanisms. First, collaterals are thought to contribute to prolonged penumbra sustenance.^11,12 Second, good retrograde collateral filling beyond the occlusion could promote successful reperfusion by providing more access to thrombolytics at the distal end of the clot and robust collaterals dissolving clot fragments in the distal vasculature.^13,14 The Highly Effective Reperfusion evaluated in Multiple Endovascular Stroke Trials (HERMES) collaboration analysis suggested a benefit with EVT across all strata of collateral circulation status;¹⁵ however, patients with poor collaterals are less likely to benefit from EVT than those with better collaterals.Most interesting, FLAIR vascular hyperintensity (FVH) on baseline MR imaging could indicate the formation of a leptomeningeal collateral circulation and serve as a prognostic marker for patients with AIS.^16-18 Both collaterals and the CBS were separately associated with functional outcome in patients undergoing EVT,^10,16 but their combined effect regarding clinical outcome is still poorly understood and has been assessed and quantified only with CTA or contrast-enhanced MRA in patients with AIS.^14,15 Furthermore, the lack of adjustment for possible confounders because of the small number of patients with very low collateral scores might also have influenced results in these studies.The purpose of this study was to determine whether there is an association between the CBS and FVH score and whether the association between the CBS and functional outcome is modified by the FVH score for patients who were treated by EVT for large-vessel occlusion within the framework of the Contact Aspiration versus Stent Retriever for Successful Revascularization (ASTER) and the THRombectomie des Artères CErebrales (THRACE) randomized trials.^19,20     

Prognostic tools for hypertrophic scar formation based on fundamental differences in systemic immunity

Unpredictable hypertrophic scarring (HS) occurs after approximately 35% of all surgical procedures and causes significant physical and psychological complaints. Parallel to the need to understanding the mechanisms underlying HS formation, a prognostic tool is needed. The objective was to determine whether (systemic) immunological differences exist between patients who develop HS and those who develop normotrophic scars (NS) and to assess whether those differences can be used to identify patients prone to developing HS. A prospective cohort study with NS and HS groups in which (a) cytokine release by peripheral blood mononuclear cells (PBMC) and (b) the irritation threshold (IT) after an irritant (sodium lauryl sulphate) patch test was evaluated. Univariate regression analysis of PBMC cytokine secretion showed that low MCP‐1, IL‐8, IL‐18 and IL‐23 levels have a strong correlation with HS (P < .010‐0.004; AUC = 0.790‐0.883). Notably, combinations of two or three cytokines (TNF‐a, MCP‐1 and IL‐23; AUC: 0.942, Nagelkerke R²: 0.727) showed an improved AUC indicating a better correlation with HS than single cytokine analysis. These combination models produce good prognostic results over a broad probability range (sensitivity: 93.8%, specificity 86.7%, accuracy 90,25% between probability 0.3 and 0.7). Furthermore, the HS group had a lower IT than the NS group and an accuracy of 68%. In conclusion, very fundamental immunological differences exist between individuals who develop HS and those who do not, whereas the cytokine assay forms the basis of a predictive prognostic test for HS formation, the less invasive, easily performed irritant skin patch test is more accessible for daily practice.     

Supraclavicular lymphadenopathy following COVID-19 vaccination: an increasing presentation to the two-week wait neck lump clinic?

The first COVID-19 vaccination was given in December 2020 and there is an effort to vaccinate the international population on a massive scale. Common side effects from the vaccine include headache and tiredness. Regional lymphadenopathy has been described in relation to other vaccines. We describe two cases of supraclavicular reactive lymphadenopathy presenting in patients who had the COVID vaccination in the ipsilateral arm. Awareness of this diagnosis is important for patients presenting to the neck lump clinic.     

Pseudoaneurysm in the inferior alveolar artery following a bad split in bilateral sagittal split osteotomy

Pseudoaneurysms in the external carotid artery system are rare, mostly reported in the superficial temporal and facial arteries. The bilateral sagittal split osteotomy has a low incidence of complications requiring emergency interventions. We report the case of a patient with acute bleeding from a pseudoaneurysm of the inferior alveolar artery diagnosed by angiography and treated successfully by super-selective embolization.     

Automated synthesis of (R)-[18F]MH.MZ on the iPhase Flexlab reaction platform

(R)-[¹⁸F]MH.MZ ([¹⁸F]MH.MZ) is a promising positron emission tomography (PET) radiotracer for in vivo study of the 5-HT_2A receptor. To facilitate clinical trials, a fully automated radiosynthesis procedure for [¹⁸F]MH.MZ was developed using commercially available materials on the iPhase Flexlab module. The overall synthesis time was 100 min with a radiochemical yield of 7 ± 0.9% (n = 3). The radiochemical purity was greater than 99% for [¹⁸F]MH.MZ with a molar activity of 361 ± 57 GBq/μmol (n = 3). The protocol described herein reliably provides [¹⁸F]MH.MZ that meets all relevant release criteria for a GMP radiopharmaceutical.     

A Mathematical Model of a Thermoelectric Device for the Treatment of Whitlow by Local Hypothermia

Biomedical Engineering - A mathematical model of a thermoelectric device for the treatment of whitlow by local hypothermia is discussed. The model is based on a solution of the heat conduction task...