A reusable simulation model to evaluate the effects of walk-in for diagnostic examinations

Enabling patients to walk in for their diagnostic examination without an appointment has considerable potential in terms of quality of care, patient service, and system efficiency. We present a model to evaluate the effect of implementing a combined walk-in and appointment system, offering appointments to all patients preferring or strictly requiring these, while enabling all other patients to walk in. In a combined system, appointments can be scheduled in periods with low walk-in demand to counterbalance the possible high variability in walk-in arrival rates. We develop a discrete event simulation model, combined with an intelligent algorithmic methodology for appointment schedule optimization, for evaluating the implementation of a combined walk-in and appointment system for diagnostic examinations. Our simulation model is reusable: its component-based structure and generic underlying logic enable it to automatically represent any type of diagnostic facility, for which it can then evaluate the effect of implementing a combined walk-in and appointment system. Applying this approach, we quantitatively investigate the impact of implementing a combined walk-in and appointment system for CT-scans, performing a case study at the Academic Medical Center (AMC) Amsterdam. Inspired by the results, the AMC CT-facility has implemented a combined walk-in and appointment system, thereby shortening patients’ diagnostic trajectories, and decreasing the number of required hospital visits for many patients

Do older patients with acute or subacute subdural hematoma benefit from surgery?

Purpose: According to the international guidelines, acute subdural hematomas (aSDH) with a thickness of >10 mm, or causing a midline shift of >5 mm, should be surgically evacuated. However, high mortality rates in older patients resulted in ongoing controversy whether elderly patients benefit from surgery. We identified predictors of outcome in a single-centre cohort of elderly patients undergoing surgical evacuation of aSDH or subacute subdural hematoma (saSDH). Materials and methods: This retrospective study included all patients aged ≥65 years undergoing surgical evacuation of aSDH/saSDH from 2000 to 2015. One-year outcome was dichotomized into favourable (Glasgow Outcome Scale (GOS) 4–5) and unfavourable (GOS 1–3). Predictors of outcome were identified by analysing patient characteristics. Results: Eighty-four patients aged ≥65 years underwent craniotomy for aSDH/saSDH during the 16 year time period. Twenty-five percent regained functional independence, 11% survived severely disabled, and 64% died. Most patients died of respiratory failure following withdrawal of artificial respiration or following restriction of treatment. Age of the SDH or Glasgow Coma Scores ≤8/intubation did not predict unfavourable outcome. All patients with bilaterally absent pupillary light reflexes died, also those who still exhibited one normal-sized pupil. Conclusion: The low number of operated patients per year probably suggests that this cohort represents a selection of patients who were judged to have good chances of favouring from surgery. Functional independence at one-year follow-up was reached in 25% of patients, 64% died. Patients with bilaterally absent pupillary light reflexes did not benefit from surgery. The tendency to restrict treatment because of presumed poor prognosis may have acted as a self-fulfilling prophecy

Intracranial carotid artery calcification subtype and collaterals in patients undergoing endovascular thrombectomy

Background and aims: Distinct subtypes of intracranial carotid artery calcification (ICAC) have been found (i.e., medial and intimal), which may differentially be associated with the formation of collaterals. We investigated the association of ICAC subtype with collateral status in patients undergoing endovascular thrombectomy (EVT) for ischemic stroke. We further investigated whether ICAC subtype modified the association between collateral status and functional outcome. Methods: We used data from 2701 patients with ischemic stroke undergoing EVT. Presence and subtype of ICAC were assessed on baseline non-contrast CT. Collateral status was assessed on baseline CT angiography using a visual scale from 0 (absent) to 3 (good). We investigated the association of ICAC subtype with collateral status using ordinal and binary logistic regression. Next, we assessed whether ICAC subtype modified the association between collateral status and functional outcome (modified Rankin Scale, 0–6). Results: Compared to patients without ICAC, we found no association of intimal or medial ICAC with collateral status (ordinal variable). When collateral grades were dichotomized (3 versus 0–2), we found that intimal ICAC was significantly associated with good collaterals in comparison to patients without ICAC (aOR, 1.41 [95%CI:1.06–1.89]) or with medial ICAC (aOR, 1.50 [95%CI:1.14–1.97]). The association between higher collateral grade and better functional outcome was significantly modified by ICAC subtype (p for interaction = 0.01). Conclusions: Patients with intimal ICAC are more likely to have good collaterals and benefit more from an extensive collateral circulation in terms of functional outcome after EVT

Intracranial carotid artery calcification subtype and collaterals in patients undergoing endovascular thrombectomy

Background and aims: Distinct subtypes of intracranial carotid artery calcification (ICAC) have been found (i.e., medial and intimal), which may differentially be associated with the formation of collaterals. We investigated the association of ICAC subtype with collateral status in patients undergoing endovascular thrombectomy (EVT) for ischemic stroke. We further investigated whether ICAC subtype modified the association between collateral status and functional outcome. Methods: We used data from 2701 patients with ischemic stroke undergoing EVT. Presence and subtype of ICAC were assessed on baseline non-contrast CT. Collateral status was assessed on baseline CT angiography using a visual scale from 0 (absent) to 3 (good). We investigated the association of ICAC subtype with collateral status using ordinal and binary logistic regression. Next, we assessed whether ICAC subtype modified the association between collateral status and functional outcome (modified Rankin Scale, 0–6). Results: Compared to patients without ICAC, we found no association of intimal or medial ICAC with collateral status (ordinal variable). When collateral grades were dichotomized (3 versus 0–2), we found that intimal ICAC was significantly associated with good collaterals in comparison to patients without ICAC (aOR, 1.41 [95%CI:1.06–1.89]) or with medial ICAC (aOR, 1.50 [95%CI:1.14–1.97]). The association between higher collateral grade and better functional outcome was significantly modified by ICAC subtype (p for interaction = 0.01). Conclusions: Patients with intimal ICAC are more likely to have good collaterals and benefit more from an extensive collateral circulation in terms of functional outcome after EVT.</p

Association between thrombus composition and stroke etiology in the MR CLEAN Registry biobank

Purpose: The composition of thrombi retrieved during endovascular thrombectomy (EVT) in acute ischemic stroke (AIS) due to large vessel occlusion (LVO) may differ depending on their origin. In this study, we investigated the association between thrombus composition and stroke etiology in a large population of patients from the Dutch MR CLEAN Registry treated with EVT in daily clinical practice. Methods: The thrombi of 332 patients with AIS were histologically analyzed for red blood cells (RBC), fibrin/platelets (F/P), and white blood cells (leukocytes) using a machine learning algorithm. Stroke etiology was assessed using the Trial of Org 10,172 in acute stroke treatment (TOAST) classification. Results: The thrombi of cardioembolic origin contained less RBC and more F/P than those of non-cardioembolic origin (25.8% vs 41.2% RBC [p = 0.003] and 67.1% vs 54.5% F/P [p = 0.004]). The likelihood of a non-cardioembolic source of stroke increased with increasing thrombus RBC content (OR 1.02; [95% CI 1.00–1.06] for each percent increase) and decreased with a higher F/P content (OR 1.02; [95% CI 1.00–1.06]). Thrombus composition in patients with a cardioembolic origin and undetermined origin was similar. Conclusion: Thrombus composition is significantly associated with stroke etiology, with an increase in RBC and a decrease in F/P raising the odds for a non-cardioembolic cause. No difference between composition of cardioembolic thrombi and of undetermined origin was seen. This emphasizes the need for more extensive monitoring for arrhythmias and/or extended cardiac analysis in case of an undetermined origin

Extracranial carotid disease and effect of intra-arterial treatment in patients with proximal anterior circulation stroke in MR CLEAN

Background: The presence of extracranial carotid disease (ECD) is associated with less favorable clinical outcomes in patients with acute ischemic stroke caused by intracranial proximal occlusion. Acute intra-arterial treatment (IAT) in the setting of extracranial and intracranial lesions is considered challenging, and whether it yields improved outcomes remains uncertain. Objective: To examine whether the presence of ECD modified the effect of IAT for intracranial proximal anterior circulation occlusion. Design: Prespecified subgroup analysis of a randomized clinical trial of endovascular treatment for acute ischemic stroke in the Netherlands. (Trial registrations: NTR1804 [Netherlands Trial Register] and ISRCTN10888758) Setting: 16 hospitals in the Netherlands. Patients: Acute ischemic stroke caused by proximal intracranial arterial occlusion of the anterior circulation. Extracranial carotid disease was defined as cervical internal carotid artery stenosis (>50%) or occlusion. Intervention: IAT treatment versus no IAT. Measurements: The primary outcome was functional outcome, as measured by the modified Rankin Scale at 90 days and reported as adjusted common odds ratio (acOR) for a shift in direction of a better outcome. Multivariable ordinal logistic regression analysis with an interaction term was used to estimate treatment effect modification by ECD. Results: The overall acOR was 1.67 (95% CI, 1.21 to 2.30) in favor of the intervention. The acOR was 3.1 (CI, 1.7 to 5.8) in the prespecified subgroup of patients with ECD versus 1.3 (CI, 0.9 to 1.9) in patients presenting without ECD. Both acORs are in favor of the intervention (P for interaction = 0.07). Limitation: The study was not powered for subgroup analysis. Conclusion: Intra-arterial treatment may be at least as effective in patients with ECD as in those without ECD, and it should not be withheld in these complex patients with acute ischemic stroke

Association between thrombus composition and stroke etiology in the MR CLEAN Registry biobank

Purpose: The composition of thrombi retrieved during endovascular thrombectomy (EVT) in acute ischemic stroke (AIS) due to large vessel occlusion (LVO) may differ depending on their origin. In this study, we investigated the association between thrombus composition and stroke etiology in a large population of patients from the Dutch MR CLEAN Registry treated with EVT in daily clinical practice. Methods: The thrombi of 332 patients with AIS were histologically analyzed for red blood cells (RBC), fibrin/platelets (F/P), and white blood cells (leukocytes) using a machine learning algorithm. Stroke etiology was assessed using the Trial of Org 10,172 in acute stroke treatment (TOAST) classification. Results: The thrombi of cardioembolic origin contained less RBC and more F/P than those of non-cardioembolic origin (25.8% vs 41.2% RBC [p = 0.003] and 67.1% vs 54.5% F/P [p = 0.004]). The likelihood of a non-cardioembolic source of stroke increased with increasing thrombus RBC content (OR 1.02; [95% CI 1.00–1.06] for each percent increase) and decreased with a higher F/P content (OR 1.02; [95% CI 1.00–1.06]). Thrombus composition in patients with a cardioembolic origin and undetermined origin was similar. Conclusion: Thrombus composition is significantly associated with stroke etiology, with an increase in RBC and a decrease in F/P raising the odds for a non-cardioembolic cause. No difference between composition of cardioembolic thrombi and of undetermined origin was seen. This emphasizes the need for more extensive monitoring for arrhythmias and/or extended cardiac analysis in case of an undetermined origin