Detection of Cardioembolic Sources With Nongated Cardiac Computed Tomography Angiography in Acute Stroke: Results From the ENCLOSE Study

Abstract

BACKGROUND: Identifying cardioembolic sources in patients with acute ischemic stroke is important for the choice of secondary prevention strategies. We prospectively investigated the yield of admission (spectral) nongated cardiac computed tomography angiography (CTA) to detect cardioembolic sources in stroke. METHODS: Participants of the ENCLOSE study (Improved Prediction of Recurrent Stroke and Detection of Small Volume Stroke) with transient ischemic attack or acute ischemic stroke with assessable nongated head-to-heart CTA at the University Medical Center Utrecht were included between June 2017 and March 2022. The presence of cardiac thrombus on cardiac CTA was based on a Likert scale and dichotomized into certainly or probably absent versus possibly, probably, or certainly present. The diagnostic certainty of cardiac thrombus was evaluated again on spectral computed tomography reconstructions. The likelihood of a cardioembolic source was determined post hoc by an expert panel in patients with cardiac thrombus on CTA. Parametric and nonparametric tests were used to compare the outcome groups. RESULTS: Forty four (12%) of 370 included patients had a cardiac thrombus on admission CTA: 35 (9%) in the left atrial appendage and 14 (4%) in the left ventricle. Patients with cardiac thrombus had more severe strokes (median National Institutes of Health Stroke Scale score, 10 versus 4; P =0.006), had higher clot burden (median clot burden score, 9 versus 10; P =0.004), and underwent endovascular treatment more often (43% versus 20%; P <0.001) than patients without cardiac thrombus. Left atrial appendage thrombus was present in 28% and 6% of the patients with and without atrial fibrillation, respectively ( P <0.001). The diagnostic certainty for left atrial appendage thrombus was higher for spectral iodine maps compared with the conventional CTA ( P <0.001). The presence of cardiac thrombus on CTA increased the likelihood of a cardioembolic source according to the expert panel ( P <0.001). CONCLUSIONS: Extending the stroke CTA to cover the heart increases the chance of detecting cardiac thrombi and helps to identify cardioembolic sources in the acute stage of ischemic stroke with more certainty. Spectral iodine maps provide additional value for detecting left atrial appendage thrombus. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT04019483.

Non–ECG-gated cardiac CT angiography in acute stroke is feasible and detects sources of embolism

“…15,25 While we recognize this may not be comparable to TEE in diagnostic accuracy, we hypothesized that (1) diagnostic images could be possible, as cardiac sources can be detected on non-cardiac CT 26 and (2) findings may improve the detection of embolic sources compared to current standards, as TEE is not routine in etiological workup as per most major guidelines. [9][10][11] Our findings are supported by the ENCLOSE study, 19 which reported a 12% yield of cardiac thrombi in patients with acute stroke or transient ischemic attack.…”

“…12 In contrast, non-ECG-gated cCTA can be more seamlessly incorporated without significantly increased imaging time or radiation dose and without additional injection of contrast. Recent data have suggested potential utility of non-ECG-gated cCTA in providing diagnostic quality images for detecting high-risk cardioembolic sources, [17][18][19] but needs further investigation and replication.…”

Presence of Residual Cardiac Thrombus Predicts Poor Outcome in Cardioembolic Stroke After Reperfusion Therapy

“… 18 The ENCLOSE (Improved Prediction of Recurrent Stroke and Detection of Small Volume Stroke) study found that 12% of patients with acute ischemic stroke or transient ischemic attack had cardiac thrombi detected using nongated head‐to‐heart CT angiography, and this rate increased to 32% (27/84) when focusing on patients labeled as cardioembolism. 19 Similarly, Rinkel et al performed ECG‐gated cardiac CT in patients with acute ischemic stroke and identified cardiac thrombus in 8% of them, and this rate increased to 24% (35/143) in patients with cardioembolic stroke. 8 In our study, we focused on patients with acute cardioembolic stroke after reperfusion therapy and used 2‐phase cardiac CT to differentiate thrombus from slow flow effects.…”

“…Interestingly, prior anticoagulant therapy was identified as another risk factor for residual cardiac thrombi in our study, which is consistent with the findings of 2 other studies. 8 , 19 This paradox could be partially explained by subtherapeutic international normalized ratio levels in patients treated with vitamin K antagonists. 8 , 19 On the other hand, patients with persistent AF are more likely to be detected during routine clinical assessments compared with those with paroxysmal AF.…”

“… 8 , 19 This paradox could be partially explained by subtherapeutic international normalized ratio levels in patients treated with vitamin K antagonists. 8 , 19 On the other hand, patients with persistent AF are more likely to be detected during routine clinical assessments compared with those with paroxysmal AF. While the former group is more likely to receive early anticoagulation therapy due to early detection, the persistent presence of cardiac arrhythmia also increases the risk of forming cardiac thrombi and experiencing ischemic events.…”