Trial Outcomes & Findings for Left Atrial Imaging Prior to Cardioversion: Leveraging Computed Tomography to Rule Out Thrombus (NCT NCT04223505)

Results Overview

This outcome was measured by calculating the time between admission and imaging.

Recruitment status

COMPLETED

Study phase

NA

Target enrollment

102 participants

Primary outcome timeframe

From admission to imaging/spontaneous cardioversion, up to approximately 30 days.

Results posted on

2025-03-12

Participant Flow

Total of 102 participants, 52 were randomized to CCT and 50 to TEE

Participant milestones

Participant milestones
Measure	TEE Arm TEE will be performed as per clinical routine using multiple standard tomographic planes to rule-out LA/LAA thrombus. Echocardiographic analysis will include: LAA-emptying velocity, and grading the severity of LAA spontaneous ECHO. The severity of the SEC will be graded on a 4 point scale with 1 = minor homogeneous contrast enhancement, 2 = significant homogeneous contrast enhancement, 3 = significant, dense, and inhomogeneous, slow-moving contrast, and 4 = dense slow-moving contrast. Transesophageal Echocardiography (TEE): TEE is considered the reference standard to rule-out left atrial (LA) and left atrial appendage (LAA) thrombus prior to cardioversion. Several studies have examined the accuracy of TEE for detecting LAA thrombus. Compared to autopsy and intraoperative findings, TEE has a mean sensitivity of 100% and mean specificity of 99%. Although the gold standard, a TEE-guided therapy is still associated with an embolic rate of 0.8%.	CCT Arm A non-contrast enhanced prospective ECG-triggered image acquisition will be acquired. This will be followed by a contrast-enhanced prospective ECG-triggered will be acquired using tri-phasic contrast protocols. Delayed CT images will be acquired 60 seconds after initial contrast-enhanced CT scan.Cardiac CT image interpretation will be performed as per clinical routine. The LA and LAA will be assess for filling defects and characterized based upon attenuation values. If LA/LAA thrombus cannot be excluded, filling defects will be assessed on the delay images. Increases in attenuation would be consistent with pseudo-thrombus from 'slow flow' and 'incomplete opacification'. Areas where attenuation does not change significantly (persistent filling defect) will be diagnosed as thrombus. It will be recommended that patients with thrombus will undergo TEE. Contrast enhanced ECG-gated cardiac CT (CCT): Contrast enhanced ECG-gated cardiac CT (CCT) is a sensitive, noninvasive alternative method used to exclude left atrial and LAA thrombus. CCT provides high spatial and good temporal resolution and its ability to detect thrombus has been evaluated.
Overall Study STARTED	50	52
Overall Study COMPLETED	42	52
Overall Study NOT COMPLETED	8	0

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

Race and Ethnicity were not collected from any participant.

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	TEE Arm n=50 Participants TEE will be performed as per clinical routine using multiple standard tomographic planes to rule-out LA/LAA thrombus. Echocardiographic analysis will include: LAA-emptying velocity, and grading the severity of LAA spontaneous ECHO. The severity of the SEC will be graded on a 4 point scale with 1 = minor homogeneous contrast enhancement, 2 = significant homogeneous contrast enhancement, 3 = significant, dense, and inhomogeneous, slow-moving contrast, and 4 = dense slow-moving contrast. Transesophageal Echocardiography (TEE): TEE is considered the reference standard to rule-out left atrial (LA) and left atrial appendage (LAA) thrombus prior to cardioversion. Several studies have examined the accuracy of TEE for detecting LAA thrombus. Compared to autopsy and intraoperative findings, TEE has a mean sensitivity of 100% and mean specificity of 99%. Although the gold standard, a TEE-guided therapy is still associated with an embolic rate of 0.8%.	CCT Arm n=52 Participants A non-contrast enhanced prospective ECG-triggered image acquisition will be acquired. This will be followed by a contrast-enhanced prospective ECG-triggered will be acquired using tri-phasic contrast protocols. Delayed CT images will be acquired 60 seconds after initial contrast-enhanced CT scan.Cardiac CT image interpretation will be performed as per clinical routine. The LA and LAA will be assess for filling defects and characterized based upon attenuation values. If LA/LAA thrombus cannot be excluded, filling defects will be assessed on the delay images. Increases in attenuation would be consistent with pseudo-thrombus from 'slow flow' and 'incomplete opacification'. Areas where attenuation does not change significantly (persistent filling defect) will be diagnosed as thrombus. It will be recommended that patients with thrombus will undergo TEE. Contrast enhanced ECG-gated cardiac CT (CCT): Contrast enhanced ECG-gated cardiac CT (CCT) is a sensitive, noninvasive alternative method used to exclude left atrial and LAA thrombus. CCT provides high spatial and good temporal resolution and its ability to detect thrombus has been evaluated.	Total n=102 Participants Total of all reporting groups
Age, Continuous	67.2 years STANDARD_DEVIATION 11.8 • n=50 Participants	66.3 years STANDARD_DEVIATION 11.3 • n=52 Participants	66.76 years STANDARD_DEVIATION 11.52 • n=102 Participants
Sex: Female, Male Female	14 Participants n=50 Participants	14 Participants n=52 Participants	28 Participants n=102 Participants
Sex: Female, Male Male	36 Participants n=50 Participants	38 Participants n=52 Participants	74 Participants n=102 Participants
Race and Ethnicity Not Collected	—	—	0 Participants Race and Ethnicity were not collected from any participant.
Region of Enrollment Canada	50 participants n=50 Participants	52 participants n=52 Participants	102 participants n=102 Participants

PRIMARY outcome

Timeframe: From admission to imaging/spontaneous cardioversion, up to approximately 30 days.

This outcome was measured by calculating the time between admission and imaging.

Outcome measures

Outcome measures
Measure	TEE Arm n=50 Participants TEE will be performed as per clinical routine using multiple standard tomographic planes to rule-out LA/LAA thrombus. Echocardiographic analysis will include: LAA-emptying velocity, and grading the severity of LAA spontaneous ECHO. The severity of the SEC will be graded on a 4 point scale with 1 = minor homogeneous contrast enhancement, 2 = significant homogeneous contrast enhancement, 3 = significant, dense, and inhomogeneous, slow-moving contrast, and 4 = dense slow-moving contrast. Transesophageal Echocardiography (TEE): TEE is considered the reference standard to rule-out left atrial (LA) and left atrial appendage (LAA) thrombus prior to cardioversion. Several studies have examined the accuracy of TEE for detecting LAA thrombus. Compared to autopsy and intraoperative findings, TEE has a mean sensitivity of 100% and mean specificity of 99%. Although the gold standard, a TEE-guided therapy is still associated with an embolic rate of 0.8%.	CCT Arm n=52 Participants A non-contrast enhanced prospective ECG-triggered image acquisition will be acquired. This will be followed by a contrast-enhanced prospective ECG-triggered will be acquired using tri-phasic contrast protocols. Delayed CT images will be acquired 60 seconds after initial contrast-enhanced CT scan.Cardiac CT image interpretation will be performed as per clinical routine. The LA and LAA will be assess for filling defects and characterized based upon attenuation values. If LA/LAA thrombus cannot be excluded, filling defects will be assessed on the delay images. Increases in attenuation would be consistent with pseudo-thrombus from 'slow flow' and 'incomplete opacification'. Areas where attenuation does not change significantly (persistent filling defect) will be diagnosed as thrombus. It will be recommended that patients with thrombus will undergo TEE. Contrast enhanced ECG-gated cardiac CT (CCT): Contrast enhanced ECG-gated cardiac CT (CCT) is a sensitive, noninvasive alternative method used to exclude left atrial and LAA thrombus. CCT provides high spatial and good temporal resolution and its ability to detect thrombus has been evaluated.
Time to Imaging	28.1 hours Standard Deviation 34.9	7.1 hours Standard Deviation 12.5

SECONDARY outcome

Timeframe: From admission to cardioversion, up to approximately 30 days

This outcome was measured by calculating the time between admission and cardioversion.

Outcome measures

Outcome measures
Measure	TEE Arm n=50 Participants TEE will be performed as per clinical routine using multiple standard tomographic planes to rule-out LA/LAA thrombus. Echocardiographic analysis will include: LAA-emptying velocity, and grading the severity of LAA spontaneous ECHO. The severity of the SEC will be graded on a 4 point scale with 1 = minor homogeneous contrast enhancement, 2 = significant homogeneous contrast enhancement, 3 = significant, dense, and inhomogeneous, slow-moving contrast, and 4 = dense slow-moving contrast. Transesophageal Echocardiography (TEE): TEE is considered the reference standard to rule-out left atrial (LA) and left atrial appendage (LAA) thrombus prior to cardioversion. Several studies have examined the accuracy of TEE for detecting LAA thrombus. Compared to autopsy and intraoperative findings, TEE has a mean sensitivity of 100% and mean specificity of 99%. Although the gold standard, a TEE-guided therapy is still associated with an embolic rate of 0.8%.	CCT Arm n=52 Participants A non-contrast enhanced prospective ECG-triggered image acquisition will be acquired. This will be followed by a contrast-enhanced prospective ECG-triggered will be acquired using tri-phasic contrast protocols. Delayed CT images will be acquired 60 seconds after initial contrast-enhanced CT scan.Cardiac CT image interpretation will be performed as per clinical routine. The LA and LAA will be assess for filling defects and characterized based upon attenuation values. If LA/LAA thrombus cannot be excluded, filling defects will be assessed on the delay images. Increases in attenuation would be consistent with pseudo-thrombus from 'slow flow' and 'incomplete opacification'. Areas where attenuation does not change significantly (persistent filling defect) will be diagnosed as thrombus. It will be recommended that patients with thrombus will undergo TEE. Contrast enhanced ECG-gated cardiac CT (CCT): Contrast enhanced ECG-gated cardiac CT (CCT) is a sensitive, noninvasive alternative method used to exclude left atrial and LAA thrombus. CCT provides high spatial and good temporal resolution and its ability to detect thrombus has been evaluated.
Time to Cardioversion	4.6 days Standard Deviation 11.1	1.7 days Standard Deviation 1.8

OTHER_PRE_SPECIFIED outcome

Timeframe: From admission to hospital discharge, up to approximately 90 days.

This outcome was measured by calculating the time between admission and hospital discharge.

Outcome measures

Outcome measures
Measure	TEE Arm n=50 Participants TEE will be performed as per clinical routine using multiple standard tomographic planes to rule-out LA/LAA thrombus. Echocardiographic analysis will include: LAA-emptying velocity, and grading the severity of LAA spontaneous ECHO. The severity of the SEC will be graded on a 4 point scale with 1 = minor homogeneous contrast enhancement, 2 = significant homogeneous contrast enhancement, 3 = significant, dense, and inhomogeneous, slow-moving contrast, and 4 = dense slow-moving contrast. Transesophageal Echocardiography (TEE): TEE is considered the reference standard to rule-out left atrial (LA) and left atrial appendage (LAA) thrombus prior to cardioversion. Several studies have examined the accuracy of TEE for detecting LAA thrombus. Compared to autopsy and intraoperative findings, TEE has a mean sensitivity of 100% and mean specificity of 99%. Although the gold standard, a TEE-guided therapy is still associated with an embolic rate of 0.8%.	CCT Arm n=52 Participants A non-contrast enhanced prospective ECG-triggered image acquisition will be acquired. This will be followed by a contrast-enhanced prospective ECG-triggered will be acquired using tri-phasic contrast protocols. Delayed CT images will be acquired 60 seconds after initial contrast-enhanced CT scan.Cardiac CT image interpretation will be performed as per clinical routine. The LA and LAA will be assess for filling defects and characterized based upon attenuation values. If LA/LAA thrombus cannot be excluded, filling defects will be assessed on the delay images. Increases in attenuation would be consistent with pseudo-thrombus from 'slow flow' and 'incomplete opacification'. Areas where attenuation does not change significantly (persistent filling defect) will be diagnosed as thrombus. It will be recommended that patients with thrombus will undergo TEE. Contrast enhanced ECG-gated cardiac CT (CCT): Contrast enhanced ECG-gated cardiac CT (CCT) is a sensitive, noninvasive alternative method used to exclude left atrial and LAA thrombus. CCT provides high spatial and good temporal resolution and its ability to detect thrombus has been evaluated.
Time to Hospital Discharge	6.7 days Standard Deviation 6.9	7.0 days Standard Deviation 10.8

OTHER_PRE_SPECIFIED outcome

Timeframe: At hospital discharge

This outcome was calculated from the following QoLs: European Quality of Life 5 Dimensions 5 Level Version (EQ-5D-5L) and Atrial Fibrillation Impact (AFImpact). EQ-5D-5L health score is a continuous scale from 0 to 100 with 100 being the best outcome. AFImpact scores were calculated using a seven-point Likert Scale (1=none of the time, 7=all of the time). AFImpact-Vitality, Emotional Distress, Sleep score (AFImpact-VEDS) was calculated using all questions in the questionnaire. The difference between AFImpact-VEDS scores at hospital admission and discharge was calculated where minimum change in score is 0 and maximum change in score is 108. AFImpact-emotional distress subscale score was calculated using 8 questions about emotional distress. The difference between AFImpact emotional distress scores at hospital admission and discharge was calculated where minimum change in score is 0 and maximum change in score is 48. The higher change in AFImpact scores represented a better outcome.

Outcome measures

Outcome measures
Measure	TEE Arm n=50 Participants TEE will be performed as per clinical routine using multiple standard tomographic planes to rule-out LA/LAA thrombus. Echocardiographic analysis will include: LAA-emptying velocity, and grading the severity of LAA spontaneous ECHO. The severity of the SEC will be graded on a 4 point scale with 1 = minor homogeneous contrast enhancement, 2 = significant homogeneous contrast enhancement, 3 = significant, dense, and inhomogeneous, slow-moving contrast, and 4 = dense slow-moving contrast. Transesophageal Echocardiography (TEE): TEE is considered the reference standard to rule-out left atrial (LA) and left atrial appendage (LAA) thrombus prior to cardioversion. Several studies have examined the accuracy of TEE for detecting LAA thrombus. Compared to autopsy and intraoperative findings, TEE has a mean sensitivity of 100% and mean specificity of 99%. Although the gold standard, a TEE-guided therapy is still associated with an embolic rate of 0.8%.	CCT Arm n=52 Participants A non-contrast enhanced prospective ECG-triggered image acquisition will be acquired. This will be followed by a contrast-enhanced prospective ECG-triggered will be acquired using tri-phasic contrast protocols. Delayed CT images will be acquired 60 seconds after initial contrast-enhanced CT scan.Cardiac CT image interpretation will be performed as per clinical routine. The LA and LAA will be assess for filling defects and characterized based upon attenuation values. If LA/LAA thrombus cannot be excluded, filling defects will be assessed on the delay images. Increases in attenuation would be consistent with pseudo-thrombus from 'slow flow' and 'incomplete opacification'. Areas where attenuation does not change significantly (persistent filling defect) will be diagnosed as thrombus. It will be recommended that patients with thrombus will undergo TEE. Contrast enhanced ECG-gated cardiac CT (CCT): Contrast enhanced ECG-gated cardiac CT (CCT) is a sensitive, noninvasive alternative method used to exclude left atrial and LAA thrombus. CCT provides high spatial and good temporal resolution and its ability to detect thrombus has been evaluated.
QoL European Quality of Life 5 Dimensions 5 Level Version (EQ-5D-5L)	68.1 score Standard Deviation 18.2	75.3 score Standard Deviation 15.5
QoL AFImpact-Vitality, Emotional Distress, Sleep score (AFImpact-VEDS)	8.5 score Standard Deviation 4.2	7.5 score Standard Deviation 3.5
QoL Atrial Fibrillation Impact (AFImpact)-emotional distress	3.0 score Standard Deviation 1.8	2.4 score Standard Deviation 1.2

Adverse Events

TEE Arm

Serious events: 0 serious events

Other events: 14 other events

Deaths: 1 deaths

CCT Arm

Serious events: 0 serious events

Other events: 17 other events

Deaths: 1 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Other adverse events
Measure	TEE Arm n=50 participants at risk TEE will be performed as per clinical routine using multiple standard tomographic planes to rule-out LA/LAA thrombus. Echocardiographic analysis will include: LAA-emptying velocity, and grading the severity of LAA spontaneous ECHO. The severity of the SEC will be graded on a 4 point scale with 1 = minor homogeneous contrast enhancement, 2 = significant homogeneous contrast enhancement, 3 = significant, dense, and inhomogeneous, slow-moving contrast, and 4 = dense slow-moving contrast. Transesophageal Echocardiography (TEE): TEE is considered the reference standard to rule-out left atrial (LA) and left atrial appendage (LAA) thrombus prior to cardioversion. Several studies have examined the accuracy of TEE for detecting LAA thrombus. Compared to autopsy and intraoperative findings, TEE has a mean sensitivity of 100% and mean specificity of 99%. Although the gold standard, a TEE-guided therapy is still associated with an embolic rate of 0.8%.	CCT Arm n=52 participants at risk A non-contrast enhanced prospective ECG-triggered image acquisition will be acquired. This will be followed by a contrast-enhanced prospective ECG-triggered will be acquired using tri-phasic contrast protocols. Delayed CT images will be acquired 60 seconds after initial contrast-enhanced CT scan.Cardiac CT image interpretation will be performed as per clinical routine. The LA and LAA will be assess for filling defects and characterized based upon attenuation values. If LA/LAA thrombus cannot be excluded, filling defects will be assessed on the delay images. Increases in attenuation would be consistent with pseudo-thrombus from 'slow flow' and 'incomplete opacification'. Areas where attenuation does not change significantly (persistent filling defect) will be diagnosed as thrombus. It will be recommended that patients with thrombus will undergo TEE. Contrast enhanced ECG-gated cardiac CT (CCT): Contrast enhanced ECG-gated cardiac CT (CCT) is a sensitive, noninvasive alternative method used to exclude left atrial and LAA thrombus. CCT provides high spatial and good temporal resolution and its ability to detect thrombus has been evaluated.
Renal and urinary disorders Renal impairment	28.0% 14/50 • Adverse event data was collected for 1 months.	32.7% 17/52 • Adverse event data was collected for 1 months.

Additional Information

Dr. Benjamin Chow

University of Ottawa Heart Institute

Phone: 6136966786

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place