DAYLIGHT
Extended CT angiography versus standard CT angiography for the detection of cardioaortic thrombus in patients with ischaemic stroke and transient ischaemic attack (DAYLIGHT): a prospective, randomised, open-label, blinded end-point trial
Clinical Question
Does extended head-to-heart CT angiography increase detection of cardioaortic thrombus in acute stroke or TIA without delaying treatment?
Study Overview
Objective
To evaluate whether extended non-gated CT angiography (CTA) during acute stroke imaging improves detection of cardioaortic thrombi compared to standard CTA.
Study Summary
Extended CTA covering the left atrial appendage significantly increased detection of cardioaortic thrombi in patients with ischemic stroke or TIA, without delaying care.
Intervention
Head-to-neck CTA extended ≥6 cm below the carina during acute stroke code vs. standard head and neck CTA.
Patients per Arm
Extended CTA: 226; Standard CTA: 239
Bottom Line
Extended CT angiography significantly improves detection of cardioaortic thrombus without delaying stroke care or increasing adverse effects, suggesting a simple and feasible strategy to enhance early cardiac source detection.
Major Points
- Randomized, blinded-endpoint trial comparing standard vs extended CT angiography in acute stroke/TIA
- Detection of cardioaortic thrombus significantly higher in extended CT group (8.8% vs. 1.7%; OR 5.70, 95% CI 1.92–16.96, p=0.002)
- No delay in imaging or acute treatments (median time 21 min vs 20 min, p=0.67)
- Number needed to screen = 14 (95% CI 9–32) for detection of 1 thrombus
- Additional radiation exposure was minimal (~1.1–1.2 mSv more)
- Extended CTA may allow early thrombus detection before it is dissolved by thrombolysis or anticoagulation
Design
Study Type: Randomized, open-label, blinded-endpoint trial
Randomization: 1
Blinding: Blinded outcome adjudication
Enrollment Period: July 17, 2023 – May 6, 2024
Follow-up Duration: ≥30 days
Centers: 1
Countries: Canada
Sample Size: 830
Analysis: Modified intention-to-treat; logistic regression with prespecified and post-hoc sensitivity analyses
Inclusion Criteria
- Adults ≥18 years
- Assessed during acute code stroke with suspected ischaemic stroke or TIA
Exclusion Criteria
- Known allergy or safety concern with iodinated contrast agents (e.g., severe renal failure)
- No intravenous access
Arms
| Field | Extended CT Angiography | Control |
|---|---|---|
| Intervention | Non-ECG-gated CTA extended ≥6 cm below carina to image left atrial appendage and heart | Head and neck CTA to aortic arch (standard care) |
| Duration | Single diagnostic scan | Single diagnostic scan |
Outcomes
| Outcome | Type | Control | Intervention | HR / OR / RR | P-value |
|---|---|---|---|---|---|
| Detection of confirmed or highly suspected cardioaortic thrombus ≥30 days after qualifying event (modified ITT: extended n=226, standard n=239) | Primary | 1.7% (4/239) | 8.8% (20/226) | 5.70 | 0.002 |
| Cardioaortic thrombus, vegetation, or tumour | Secondary | 2.9% (7/239) | 9.7% (22/226) | 3.57 | 0.004 |
| Any cardioembolic source (composite) | Secondary | 30.5% (73/239) | 38.5% (87/226) | 1.42 | 0.07 |
| Cardioaortic embolic source detection resulting in de novo therapy | Secondary | 13.4% (32/239) | 12.4% (28/226) | 0.91 | 0.75 |
| Denominators | Adverse | ||||
| Time to CTA Completion (min, as-treated) | Adverse | 20.0 (IQR 17.0–26.0) | 21.0 (IQR 15.8–27.0) | 0.67 | |
| Radiation Exposure (mSv, as-treated) | Adverse | 15.0 (SD 4.3) | 16.1 (SD 2.4) | 0.0013 | |
| Contrast-Induced Nephropathy (as-treated) | Adverse | 1/235 | 0/230 | ||
Subgroup Analysis
No significant interaction across subgroups including age, sex, AF status, or stroke severity
Criticisms
- Single-centre design may limit external validity
- Incomplete follow-up with advanced cardiac imaging
- Possible underdetection or misclassification of thrombi
- No evaluation of long-term clinical outcomes such as recurrence or mortality
Funding
Western University and the Kathleen and Dr Henry Barnett Chair in Stroke Research
Based on: DAYLIGHT (The Lancet Neurology, 2025)
Authors: Luciano A Sposato, Diana Ayan, Mobeen Ahmed, ..., Rodrigo Bagur
Citation: Lancet Neurol. 2025;24:489–499
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