Predictors of Atrial Fibrillation in Patients With Stroke Attributed to Large- or Small-Vessel Disease: A Prespecified Secondary Analysis of the STROKE AF Randomized Clinical Trial

Importance

The Stroke of Known Cause and Underlying Atrial Fibrillation (STROKE AF) trial found that approximately 1 in 8 patients with recent ischemic stroke attributed to large- or small-vessel disease had poststroke atrial fibrillation (AF) detected by an insertable cardiac monitor (ICM) at 12 months. Identifying predictors of AF could be useful when considering an ICM in routine poststroke clinical care.

Objective

To determine the association between commonly assessed risk factors and poststroke detection of new AF in the STROKE AF cohort monitored by ICM.

Design, Setting, and Participants

This was a prespecified analysis of a randomized (1:1) clinical trial that enrolled patients between April 1, 2016, and July 12, 2019, with primary follow-up through 2020 and mean (SD) duration of 11.0 (3.0) months. Eligible patients were selected from 33 clinical research sites in the US. Patients had an index stroke attributed to large- or small-vessel disease and were 60 years or older or aged 50 to 59 years with at least 1 additional stroke risk factor. A total of 496 patients were enrolled, and 492 were randomly assigned to study groups (3 did not meet inclusion criteria, and 1 withdrew consent). Patients in the ICM group had the index stroke within 10 days before insertion. Data were analyzed from October 8, 2021, to January 28, 2022.

Interventions

ICM monitoring vs site-specific usual care (short-duration external cardiac monitoring).

Main Outcomes and Measures

The ICM device automatically detects AF episodes 2 or more minutes in length; episodes were adjudicated by an expert committee. Cox regression multivariable modeling included all parameters identified in the univariate analysis having P values <.10. AF detection rates were calculated using Kaplan-Meier survival estimates.

Results

The analysis included the 242 participants randomly assigned to the ICM group in the STROKE AF study. Among 242 patients monitored with ICM, 27 developed AF (mean [SD] age, 66.6 [9.3] years; 144 men [60.0%]; 96 [40.0%] women). Two patients had missing baseline data and exited the study early. Univariate predictors of AF detection included age (per 1-year increments: hazard ratio [HR], 1.05; 95% CI, 1.01-1.09; P = .02), CHA2DS2-VASc score (per point: HR, 1.54; 95% CI, 1.15-2.06; P = .004), chronic obstructive pulmonary disease (HR, 2.49; 95% CI, 0.86-7.20; P = .09), congestive heart failure (CHF; with preserved or reduced ejection fraction: HR, 6.64; 95% CI, 2.29-19.24; P < .001), left atrial enlargement (LAE; HR, 3.63; 95% CI, 1.55-8.47; P = .003), QRS duration (HR, 1.02; 95% CI, 1.00-1.04; P = .04), and kidney dysfunction (HR, 3.58; 95% CI, 1.35-9.46; P = .01). In multivariable modeling (n = 197), only CHF (HR, 5.06; 95% CI, 1.45-17.64; P = .05) and LAE (HR, 3.32; 1.34-8.19; P = .009) remained significant predictors of AF. At 12 months, patients with CHF and/or LAE (40 of 142 patients) had an AF detection rate of 23.4% vs 5.0% for patients with neither (HR, 5.1; 95% CI, 2.0-12.8; P < .001).

Conclusions and Relevance

Among patients with ischemic stroke attributed to large- or small-vessel disease, CHF and LAE were associated with a significantly increased risk of poststroke AF detection. These patients may benefit most from the use of ICMs as part of a secondary stroke prevention strategy. However, the study was not powered for clinical predictors of AF, and therefore, other clinical characteristics may not have reached statistical significance.

Trial Registration

ClinicalTrials.gov Identifier: NCT02700945.

Abstract MP21: Mobile Interventional Stroke Teams Lead to Improved Outcomes in the Early Time Window for LVO Stroke

Introduction: Endovascular therapy (EVT) for large vessel occlusion (LVO) stroke is time-sensitive. At Mount Sinai Health System, we developed a novel Mobile Interventional Stroke Team (MIST) that travels to Thrombectomy Capable Stroke Centers to perform EVT, as opposed to transferring patients in the Drip-and-Ship (DS) model. We have shown significantly faster initial door-to-recanalization times and improved discharge outcomes. The effect of the MIST stratified by time of presentation has yet to be studied.

Hypothesis: In patients presenting with a last known well [LKW] of <6 hours, the MIST model leads to better clinical outcomes as compared to the DS model.

Methods: In a prospectively collected stroke database at a multicenter health system, patients undergoing EVT performed by a MIST or after transfer in a DS model from January 2017 to March 2020 with baseline mRS 0-2 were selected. Patients presenting in the early time window and late time window (LKW >6 hours) were analyzed separately. The primary endpoint was the proportion with a good outcome (mRS of 0-2) at 90 days. Secondary endpoints included discharge NIHSS and mRS.

Results: In the 242 selected patients, the MIST and DS cohorts were similar in age, gender, initial NIHSS, pre-stroke mRS, and procedural details. In the early window, 54% (39/72) had a good 90-day outcome in the MIST model, as compared to 28% (25/88) in the DS model (p<0.01). In the late window, good 90-day outcomes were similar (29% vs 43%; p=0.40). The median NIHSS at discharge was 4.0 and 12.0 in the early window (p<0.01) and 5.0 and 11.0 in the late window (p=0.16) in the MIST and DS models, respectively. The early window discharge mRS was significantly better in the MIST model (p<0.01) and similar in the late window (p=0.74).

Conclusions: The MIST model used in the early time window produces better 90-day outcomes compared to the DS model. This is likely due to the MIST’s ability to capture fast progressors in the early window.

Mobile Interventional Stroke Team Model Improves Early Outcomes in Large Vessel Occlusion Stroke

Background and Purpose:

Triage of patients with emergent large vessel occlusion stroke to primary stroke centers followed by transfer to comprehensive stroke centers leads to increased time to endovascular therapy. A Mobile Interventional Stroke Team (MIST) provides an alternative model by transferring a MIST to a Thrombectomy Capable Stroke Center (TSC) to perform endovascular therapy. Our aim is to determine whether the MIST model is more time-efficient and leads to improved clinical outcomes compared with standard drip-and-ship (DS) and mothership models.

Methods:

This is a prospective observational cohort study with 3-month follow-up between June 2016 and December 2018 at a multicenter health system, consisting of one comprehensive stroke center, 4 TSCs, and several primary stroke centers. A total of 228 of 373 patients received endovascular therapy via 1 of 4 models: mothership with patient presentation to a comprehensive stroke center, DS with patient transfer from primary stroke center or TSC to comprehensive stroke center, MIST with patient presentation to TSC and MIST transfer, or a combination of DS with patient transfer from primary stroke center to TSC and MIST. The prespecified primary end point was initial door-to-recanalization time and secondary end points measured additional time intervals and clinical outcomes at discharge and 3 months.

Results:

MIST had a faster mean initial door-to-recanalization time than DS by 83 minutes ( P <0.01). MIST and mothership had similar median door-to-recanalization times of 192 minutes and 179 minutes, respectively ( P =0.83). A greater proportion had a complete recovery (National Institutes of Health Stroke Scale of 0 or 1) at discharge in MIST compared with DS (37.9% versus 16.7%; P <0.01). MIST had 52.8% of patients with modified Rankin Scale of ≤2 at 3 months compared with 38.9% in DS ( P =0.10).

Conclusions:

MIST led to significantly faster initial door-to-recanalization times compared with DS, which was comparable to mothership. This decrease in time has translated into improved short-term outcomes and a trend towards improved long-term outcomes.

Registration:

URL: https://www.clinicaltrials.gov . Unique identifier: NCT03048292.

Abstract WP392: Non-English Speakers Present Faster with More Severe Strokes

Introduction: With the continued expansion of acute stroke treatment options, urban tertiary referral centers such as ours are treating an increasingly diverse patient population. As we attempted to better understand barriers to improved door to treatment times in our acute stroke code protocol, we postulated that there might be differences in severity of presentation and swiftness of acute stroke care based on English fluency.

Methods: Through a departmental quality improvement project to optimize local policy in the context of new acute stroke treatment guidelines, we compared National Institute of Health Stroke Scale (NIHSS) at presentation, time to presentation, and time to treatment of fluent English speakers to patients who were not fluent in English. We analyzed data from 667 acute stroke codes from January 2017 to March 2018 with Statistical Package for the Social Science (SPSS) using two-tailed t-tests.

Results: In-Hospital stroke codes included 415 English speakers and 97 non-English speakers, while Outside Hospital (OSH) transfers comprised 92 English speakers and 35 non-English speakers. Non-English-speaking patients had higher average NIHSS scores at time of acute stroke presentation (11 vs 8 (p=0.013) in-hospital and 17 vs 13(p = 0.007) OSH transfer). Last known well (LKW) to stroke code time upon arrival to our center was significantly shorter in non-English speakers compared to English speakers coming from an OSH (315 minutes vs 515 minutes, p = 0.016), but there were no statistically significant differences between language groups for in-hospital codes’ LKW to stroke code times. There were no statistically significant differences in acute treatment times, but in the OSH transfer group, average LKW to groin puncture was 349 minutes for non-English speakers compared to 545 minutes for English speakers (p=0.085).

Conclusions: This data suggests that at our center, non-English speakers present with more severe strokes and present more quickly. Increased stroke severity may partially explain an observed trend towards faster times from LKW to thrombectomy for non-English speakers transferred from an OSH.

The prognostic significance of CXCL1 hypersecretion by human colorectal cancer epithelia and myofibroblasts

Background

Clinical therapy for metastatic colorectal cancer (CRC) remains limited, especially when the tumor harbors a KRAS mutation. This study aimed to identify prognostic biomarkers in CRC that are accessible for therapeutic inhibition.

Methods

Conditioned media from human CRC epithelial cells and myofibroblasts were screened by cytokine arrays for tumorigenic factors. The protein and mRNA expressions of these factors were determined by immunohistochemistry and gene microarrays in human CRC tissues. Prognostic biomarkers were determined by correlation of mRNA expression to overall survival in stage IV CRC patients. Inhibition of CXCL1 was performed with specific neutralizing antibody and lentiviral shRNAs. Malignant growth was assessed by soft agar growth assays and xenograft tumor growth in immunocompromised mice.

Results

CXCL1 was highly secreted by KRAS mutant human CRC cells and myofibroblasts in a complementary adaptive response to serum deprivation. Elevated CXCL1 level promoted anchorage-independent growth of murine fibroblasts and human CRC cells. Inhibition of CXCL1 by neutralizing antibody and specific shRNAs decreased CRC tumor growth. Highly elevated CXCL1 expression significantly correlated with decreased overall survival in stage IV CRC patients (hazard ratio 0.28; 95% CI 0.11–0.72).

Conclusions

High CXCL1 expression is a poor prognostic biomarker in metastatic CRC. CXCL1 inhibition suppressed tumorigenic growth of KRAS mutant CRC cells.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-015-0555-4) contains supplementary material, which is available to authorized users.

Clinical characteristics of patients with lung adenocarcinomas harboring BRAF mutations

PURPOSE

BRAF mutations occur in non-small-cell lung cancer. Therapies targeting BRAF mutant tumors have recently been identified. We undertook this study to determine the clinical characteristics of patients with lung adenocarcinomas harboring BRAF mutations.

PATIENTS AND METHODS

We reviewed data from consecutive patients with lung adenocarcinoma whose tumors underwent BRAF, EGFR, and KRAS mutation testing as well as fluorescence in situ hybridization for ALK rearrangements. Patient characteristics including age, sex, race, performance status, smoking history, stage, treatment history, and overall survival were collected.

RESULTS

Among 697 patients with lung adenocarcinoma, BRAF mutations were present in 18 patients (3%; 95% CI, 2% to 4%). The BRAF mutations identified were V600E (50%), G469A (39%), and D594G (11%). Mutations in EGFR were present in 24%, KRAS in 25%, and ALK translocations in 6%. In contrast to patients with EGFR mutations and ALK rearrangements who were mostly never smokers, all patients with BRAF mutations were current or former smokers (P < .001). The median overall survival of advanced-stage patients with BRAF mutations was not reached. In comparison, the median overall survival of patients with EGFR mutations was 37 months (P = .73), with KRAS mutations was 18 months (P = .12), and with ALK rearrangements was not reached (P = .64).

CONCLUSION

BRAF mutations occur in 3% of patients with lung adenocarcinoma and occur more commonly in current and former smokers. The incidence of BRAF mutations other than V600E is significantly higher in lung cancer than in melanoma.

Natural killer cell activity following thermal injury

The role of natural killer cell activity in immunosurveillance following thermal injury remains unknown. We utilize a chromium-51-release assay of K562 targets to monitor NK activity. NK activity of peripheral blood mononuclear cells of severely burned patients (BSA greater than 20%) was determined once a week until the convalescence period was completed. From the second week after thermal injury, impairment of NK activity was demonstrated, but the differences did not reach statistical significance. However, a correlation was found between decline of NK activity and incidences of septic complications. Surprisingly, no decline in NK activity was observed in the first week after thermal injury.

Immunoglobulin E (IgE) in patients with severe burns

The concentrations of immunoglobulin E (IgE) were measured serially in 30 patients with severe burn injury. A characteristic finding was a rapid and dramatic increase of IgE in the serum of all patients, some of whom showed up to 20-fold increases. IgE was also found in considerable amounts in blister fluid and pleural effusions. In some patients raised IgE values were the only indicator of an anamnestic immediate allergic state. No correlation was found between the IgE levels and clinical characteristics of individual patients but significant changes seemed to be present only in patients with a burn covering more than 20 per cent of the body surface area.

Effect of human recombinant interleukin (IL-2) on peripheral blood mononuclear cells of burned patients

Interleukin-2 (IL-2) has been suggested to play a key role in the immune response. To investigate the effect of human recombinant IL-2 on proliferative and cytotoxic responses in burn patients, peripheral blood mononuclear cells from 20 severely burned patients (body surface area (BSA) greater than 20 per cent) were studied in this way. Proliferative response measured by tritiated thymidine uptake was impaired from week 2 following injury. IL-2-activated cytotoxicity to NK-resistant target T24 was significantly impaired from week 2. To clarify if the defect in cytotoxic response is due to a decreased number of cell precursors or due to reduced responsiveness to IL-2, a limiting dilution assay was introduced. However, there was no reduction in precursor cell numbers. These data suggest that, in addition to impaired IL-2 production, there is an endogenous defect in IL-2 responsiveness. This may be of clinical importance since it is not possible to reverse this defect, at least in vitro.