Miller, Małgorzata

Objective: Patent foramen ovale (PFO) closure is recommended for patients younger than 60 years with embolic stroke of undetermined source (ESUS) or cryptogenic stroke, but it’s role in patients older than 60 years remains unclear. We aim to investigate the benefit of closure in patients older than 60 with ESUS or cryptogenic stroke. Methods: Patients older than 60 years with ESUS or cryptogenic stroke from several large tertiary hospitals were recruited, who received a PFO closure after multidisciplinary brain-heart case conference, compared to age-matched cohort patients with ESUS or cryptogenic stroke. The primary outcome included recurrent ischemic stroke that occurred up to a median follow up of 5 years following PFO closure between two groups. The safety outcome was the occurrence of any complications after PFO closure, including new onset atrial fibrillation (AF). Results: A total of 102 patients (Table 1) were included (mean age 66±4), 56 male (55%), who received a PFO closure. Procedure-related complications, including new onset transient AF were low (1%). After following patients up to 5 years, patients with PFO closure demonstrated a relatively low incidence of recurrent ischemic stroke (3.9%, 4/102), compared to age-matched control cohort with a total of 97 patients (mean age 67±4), which had higher incidence of stroke recurrency (8.2%, 8/97) (Table 2). Kaplan-Meier event curve (Figure 1) reveals a trend of reducing recurrent stroke in patients with PFO closure but not achieved statistical significance. Conclusions: In patients with cryptogenic stroke or ESUS who are older than 60 years, PFO closure demonstrated safety profiles with a noticeable trend of reducing recurrent ischemic stroke compared to their age-matched counterparts. Prospective randomized trials are warranted in this young-older population.

Background: Timely and accurate triage of stroke patients in rural settings remains a critical challenge, especially for patients with large vessel occlusions (LVO) requiring rapid access to comprehensive stroke centers (CSCs). This project aimed to improve the efficiency and accuracy of transport decisions for EMS stroke care in rural Michigan by adapting American Heart Association (AHA) guidelines on prehospital management and EMS routing. Method: We established a novel database involving linking regional EMS records, regional hospital stroke code quality improvement data, and Get With The Guidelines–Stroke (GWTG-S) registry data for suspected and confirmed stroke cases originating from five counties within 60 minutes of an urban CSC in West Michigan. Using a stepped-wedge design, we adapted the model AHA Severity-Based Stroke Triage Algorithm and implemented it in four rural EMS agencies through a staged roll-out of educational programs delivered to EMS providers and regional ED staff. We analyzed pre- and post-intervention data to assess protocol compliance, bypass frequency, and time from EMS scene arrival to CT acquisition and reperfusion therapy delivery. Results: Among 949 (598 pre- and 351 post-intervention) stroke transports occurred between November 2021 to December 2024, guideline-compliant hospital destination selection improved from 62% to 71% (p=0.018). Stroke mimics saw the greatest improvement (72% to 88%, p<0.001) through reduced unnecessary bypass. LVO screening documentation increased (10% to 23%, p<0.001), and EMS scene arrival-to-CT time decreased by 7 minutes (95% CI: 3–11). Trends toward improved thrombolysis rates (18% to 26%, p=0.055) and faster EMS-to-needle times (99 to 87 min, p=0.059) were observed. Mechanical thrombectomy rates and transfer metrics remained unchanged. Conclusions: This project successfully implemented a rural stroke triage protocol aligned with AHA guidelines, improving EMS routing decisions and reducing time to imaging. The intervention enhanced access to thrombolysis, however did not expedite mechanical thrombectomy. Findings support the AHA protocol’s scalability and underscore the feasibility of rural stroke system optimization.

Background: CT perfusion (CTP) imaging is an important tool for identifying candidates for mechanical thrombectomy (MT). This modality is increasingly available in regional facilities, but whether pre-transfer perfusion imaging studies may be relied upon for treatment decisions is unclear. We analyzed a cohort of stroke transfers to quantify changes in CTP imaging profiles over time. Methods: A cohort of confirmed ischemic stroke patients who received CTP before and after transfer to a large mid-western comprehensive stroke center (CSC) were identified. We compared perfusion mismatch (MM), core infarct volume (CIV), and favorability of imaging for mechanical thrombectomy (MT) candidacy (defined as the presence of LVO and MM/CIV ratio of >1.8) between studies. Regression models were used to examine predictors of CIV growth including hypoperfusion intensity ratio (HIR) and time between studies. Results: Over a 24-month period, 61 patients met inclusion criteria. Median age was 71 (IQR 60-80), 52% were female, median NIHSS was 14 (IQR 4-19), and most patients had occlusion of the internal carotid and/or middle cerebral arteries (77%). The median time from last known well (LKW) to initial CT was 148 minutes (IQR 71-620) and median time between imaging studies was 149 minutes (IQR 126-194). Median CIV growth was 0 mL (IQR 0-6) and 8% (5/61) had growth ≥25 mL. In linear regression, higher HIR predicted CIV growth (β=24.3, p=0.04), but time from LKW to presentation and time between imaging studies did not. Imaging studies taken at the regional and CSC sites demonstrated excellent agreement in classifying patients as candidates for MT (kappa 0.778 [95% CI: 0.611-0.944]). A favorable regional CTP profile was 93% sensitive for MT delivery at the CSC with a positive predictive value of 63%. Conclusion: In our cohort, CIV growth between facilities was minimal despite relatively long interfacility transport times and was predicted by the regional HIR. A favorable regional imaging profile demonstrated high agreement with the imaging result at the CSC and was strongly associated with MT treatment.

Background: Emergency medical services (EMS) routing of stroke patients is challenging in rural settings. To address this, the American Stroke Association (ASA) has developed a template severity-based EMS triage algorithm to direct EMS to either the nearest stroke-ready versus the nearest Comprehensive Stroke Center (CSC) hospital, but its real-world impact is uncertain. Methods: This is an interim analysis of a before-and-after quality improvement study examining the impact of implementation of a severity-based EMS stroke destination protocol by three medical control authorities (MCAs) covering 4 rural counties in western Michigan. We defined optimal destination according to the ASA algorithm, which recommends bypass for patients within 24 of last known well if large vessel occlusion suspected and bypass will not delay thrombolysis. Chi square tests were used to compare optimal destination selection before and after implementation among EMS suspected stroke cases originating from the target counties. We also compared the time from EMS scene arrival to ischemic stroke (IS) treatment (thrombolysis or endovascular therapy [EVT]) before and after implementation using Wilcoxon Rank Sum tests. Results: From November 2021 to May 2024, EMS transported 616 suspected stroke cases, 272 (44.2%) of which ultimately received a diagnosis of ischemic stroke (IS) or transient ischemic attack. The protocol was implemented by each MCA in random order at months 21, 23, and 29, resulting in 73 MCA-months before and 17 after implementation, excluding a one-month washout for each MCA. Optimal hospital destinations were selected for 310/499 (62.1%) patients prior to the protocol and 86/117 (73.5%) after (p=0.021). Thrombolytics were administered to 57 patients (48 before and 9 after) and 46 (42 before and 4 after) received EVT. Median times from first EMS contact to needle decreased from 98 (interquartile range [IQR]: 79-107) to 77 (IQR: 75-85) minutes (p=0.012); median times from EMS contact to groin puncture increased nonsignificantly from 165 (IQR: 132-216) to 196 (IQR: 191-228) minutes (p=0.110). Conclusions: Interim analysis of implementation of a rural EMS severity-based triage algorithm for suspected stroke cases resulted in improved destination selection and faster thrombolysis but did not improve EVT treatment times. This analysis will be repeated once follow-up is completed in 7 months.

Background: Large vessel occlusion (LVO) stroke patients are often transferred from regional hospitals to comprehensive stroke centers (CSC) for thrombectomy. The need for repeat imaging at CSCs prior to intervention is unclear. We compared regional hospital and CSC perfusion imaging results for interfacility transfers in a single health system. Methods: We analyzed a cohort of patients in western Michigan who received CT perfusion imaging before and after transfer to a CSC. Perfusion mismatch (MM), core infarct volume (CIV), and favorability of imaging for mechanical thrombectomy (MT) candidacy were compared between the regional and CSC studies. A favorable imaging profile was defined as the presence of LVO, MM volume >10 mL, and MM/CIV ratio of >1.2. Linear regression was used to examine predictors of infarct growth during transfer. Results: Over a 10-month period, 25 patients met inclusion criteria. The median age was 76 (IQR 66-81), 60% were male, median NIHSS was 11 (IQR 2-18), and most patients had occlusion of the internal carotid or middle cerebral arteries (72%). The median time from last known well to initial CT was 250 minutes (IQR 85-620). Regional median MM volume was 52 mL (IQR 8-97), CIV was 0 mL (IQR 0-13), and hypoperfusion intensity ratio (HIR) was 0.25 (IQR 0-0.34). The median time between CTs was 152 minutes (IQR 139-226). The median change in MM volume was -3 mL (IQR -27-3) and median CIV growth rate was 0 mL/hr (IQR 0-2.0). In a multivariable regression model, higher HIR (β=23.2, p=0.012) and minutes between imaging studies (β=0.10, p=0.021) were associated with CIV growth. Sixteen patients (64%) had favorable imaging profiles for MT at the regional hospital. Of these, 15 (93.8%) continued to have a favorable CSC imaging profiles and 9 (56.2%) underwent MT. Of the 9 patients without favorable regional imaging profiles, 1 (11.1%) had a favorable CSC imaging profile and 2 (22.2%) underwent MT. Conclusion: In our sample, regional and CSC perfusion imaging patterns were similar and patients infrequently crossed thresholds for MT candidacy between studies. Initial HIR and longer delays between were independently associated with infarct growth during transfers, however overall infarct growth was very small.