Optimized CT-imaging Protocol in VA-ECMO Patients After CPR

November 19, 2024 updated by: Philipp Dominik Stelzer, Medical University of Vienna

Optimized CT-imaging Protocol in VA-ECMO Patients After Cardiopulmonary Resuscitation - a Single-center Prospective Non-randomized Cohort Study

Veno-arterial (VA) extracorporal membrane oxygenation (ECMO) is an increasingly applied method in patients under cardiopulmonary resuscitation (CPR), who are regularly examined with a contrast-enhanced computed tomography to search for the underlying pathology as well as complications from the implantation of the ECMO system or CPR. The extraordinary hemodynamic situation due to VA-cannulation with antegrade and retrograde perfusion is a challenge to the diagnostically required simultaneous opacification of pulmonary and systemic arterial vessels. Evidence regarding the effect of ECMO flow rate, cannula position, cardiac function and contrast agent injection site is scarce and to the best of the authors' knowledge, no standardized scan protocol for this patient collective exists.

In this study, all adult emergency department patients at our institution with femoro-femoral VA-ECMO and ongoing or recent cardiopulmonary resuscitation, who are referred to a clinically indicated CT scan in this context, will be included, aiming for a total of n=50 patients. The first 25 consecutive patients will be assigned to the intervention cohort. For these patients the ECMO flow rate is reduced by a maximum of 50% of initial flow, but to no less than 1,5 liter/min, for the duration of the CT scan (max. 1-2 minutes), given the hemodynamic and respiratory situation allows it. The following 25 consecutive patients will be assigned to the control cohort for whom ECMO flow rate is not reduced. Clinical data (e.g. ECMO flow rate, ventilation parameters, cardiac function, venous line for contrast injection) at the time of imaging will be documented via a standardized data sheet. The applied CT protocol routinely comprises a non-contrast-enhanced cranial CT (CCT), CT angiography (CTA) of the aorta as well as a portal-venous phase of the chest and abdomen. Complementary scans will be performed as clinically indicated.

The aim of this single-center prospective cohort study is to evaluate the performance of an optimized CT protocol for this patient cohort and whether a reduction of ECMO flow rate improves contrast enhancement of critically relevant vessels in these CT examinations in comparison to a non-reduction cohort.

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

Detailed Description

Background:

Extracorporal membrane oxygenation (ECMO) is an increasingly applied method of last resort for treating severe respiratory or combined cardiopulmonary failure. Different configurations of cannulation, either veno-venous (VV) or veno-arterial (VA), are used depending on indication. The latter is commonly used in patients under cardiopulmonary resuscitation to temporarily provide adequate organ-perfusion until the underlying pathology is found and treated. Alas being a revolutionary method, there is also a non-negligible number of vascular complications due to necessary insertion of cannulas in large vessels in combination with full anticoagulation. Therefore, these patients are regularly examined with a subsequent contrast-enhanced computed tomography to rule out complications and search for potential underlying causes of cardiac arrest. However, the extraordinary hemodynamic situation resulting from VA-cannulation with antegrade and retrograde perfusion challenges the diagnostically required simultaneous opacification of pulmonary and systemic arterial vessels. In this setting, siphoning, mixing and dilution effects of contrast agent and non-contrasted blood often cause incomplete or inhomogeneous vessel contrast, rendering exams partially non-diagnostic. Evidence regarding the effect of cannula position, ECMO flow rate, cardiac function and contrast agent injection site is scarce and as yet, to the best of the authors' knowledge, no standardized scan protocol for this patient collective exists.

Methods:

All adult emergency department patients at the Vienna General Hospital with femoro-femoral VA-ECMO and undergoing or recent cardiopulmonary resuscitation, who are subsequently referred to a clinically indicated CT scan for the detection of causes and complications or their exclusion, will be included in this study, aiming for a total of n=50 patients. The first 25 consecutive patients will be assigned to the intervention (flow reduction) cohort and the following 25 consecutive patients will be assigned to the control (no flow reduction) cohort. Clinical data (e.g. ECMO flow rate, ventilation parameters, cardiac function, venous line for contrast injection) at the time of imaging will be retrieved from the accompanying treating physician and are documented via a standardized data sheet.

In the intervention cohort ECMO flow rate is reduced for the duration of contrast administration and acquisition of an arterial and venous phase of the whole body (max. 1-2 minutes) given the hemodynamic and respiratory situation allows it. Whether this is possible, is determined right before the CT scan by the accompanying emergency physician and adapted to the individually tolerable level (max. 50% of initial flow, no less than 1,5 liter/min). After image acquisition, ECMO flow rate is then immediately returned to the initial or clinically optimal value at this moment. If the patient shows any signs of instability during this short period of imaging acquisition, the scan will be interrupted and immediate countermeasures will be taken by the accompanying team of emergency physicians and nurses. During the examination the vital signs of all patients are permanently monitored. The applied CT protocol is the established protocol at our department and comprises a non-contrast-enhanced cranial CT (CCT), CT angiography (CTA) of the aorta as well as a portal-venous phase of the chest and abdomen. Complementary scans, e.g. CT of cervical spine or CTA of cerebral arteries, will be performed as clinically indicated. After the examination, ECMO flow rate will be increased to the initial or at this point clinically optimal value and the acquired images are, within clinical routine, immediately reviewed and reported by the radiologist in charge. Diagnostic quality of the acquired images, vessel opacification, the impact of CT findings and diagnoses on clinical management as well as resulting management changes will be documented and analyzed.

Aims:

The aim of this single-center prospective cohort study is to evaluate the performance of an optimized CT protocol and whether a reduction of ECMO flow rate improves contrast enhancement of critically relevant vessels in CT examinations of patients after cardiopulmonary resuscitation with femoro-femoral VA-ECMO (eCPR) in comparison to a non-reduction cohort.

Study Type

Interventional

Enrollment (Estimated)

50

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Austria
      • Vienna, Austria, 1090
        • Medical University of Vienna

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Running or recent eCPR
  • Clinically indicated CT and CT angiography of chest and abdomen (and head, if required)
  • Femoro-femoral VA-ECMO-cannulation

Exclusion Criteria:

- Contraindication for CT scan or administration of iodinated contrast agent

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Diagnostic
  • Allocation: Non-Randomized
  • Interventional Model: Sequential Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: ECMO flow rate reduction
In the intervention cohort ECMO flow rate is reduced for the duration of CT image acquisition (max. 1-2 min.), if the hemodynamic and respiratory situation allows it. Feasibility is determined by the accompanying emergency physician right before the CT scan and adapted to the individually tolerable level (max. 50% of initial flow, no less than 1,5 litre/min). After image acquisition, ECMO flow rate is immediately returned to the initial or clinically optimal value at this moment.
Diagnostic test: ECMO flow rate reduction
ECMO flow rate is reduced for the duration of CT image acquisition (max. 1-2 min.), if the hemodynamic and respiratory situation allows it. Feasibility is determined by the accompanying emergency physician right before the CT scan and adapted to the individually tolerable level (max. 50% of initial flow, no less than 1,5 litre/min). After image acquisition, ECMO flow rate is immediately returned to the initial or clinically optimal value at this moment.
No Intervention: no ECMO flow rate reduction
In this cohort ECMO flow rate is not reduced for CT image acquisition.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Computed tomography vessel opacification
Time Frame: Three years
To assess and compare overall vessel opacification of eCPR patients with and without ECMO flow reduction, measured by mean HU in a representative cross-section of clinically relevant vessels.
Three years
Number and clinical impact of pathological findings
Time Frame: ten days
To assess the number and clinical impact of additional / previously unknown pathological findings in eCPR patients detected by early post-eCPR CT, measured by direct feedback of the treating emergency physician on the relevance (Likert scale 1-5) and consequences (time and type) of findings.
ten days

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Subjective CT image quality
Time Frame: Three years
To assess whether flow reduction improves subjective CT image quality compared to the no-flow reduction cohort, measured by a Likert-Scale from 1-5.
Three years
CT vessel opacification homogeneity
Time Frame: Three years
To assess whether flow reduction results in a more homogeneous vessel opacification, measured by standard deviation of HU in a representative cross-section of clinically relevant vessels.
Three years
Follow-up CT exams
Time Frame: Three years
To assess whether an all-in-one exam before ICU admission reduces number of follow-up CT exams, radiation dose and/or contrast agent dose, measured by comparing cumulative exam numbers, radiation and contrast agent dose of the study cohort to a retrospective cohort of eCPR exams.
Three years
Correlations between mean vessel opacification, subjective image quality and appearance of artifacts with intrinsic and extrinsic factors
Time Frame: Three years
To find correlations between intrinsic and extrinsic factors and mean vessel opacification, subjective image quality and appearance of artifacts, measured by correlation of mean HU for metric variables and uni- and multivariate analysis for binary variables.
Three years

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Medical University of Vienna

Investigators

  • Study Director: Dietmar Tamandl, MD, Assoc.-Prof., Medical University of Vienna

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

February 1, 2022

Primary Completion (Actual)

July 1, 2024

Study Completion (Estimated)

March 1, 2025

Study Registration Dates

First Submitted

February 21, 2022

First Submitted That Met QC Criteria

March 11, 2022

First Posted (Actual)

March 22, 2022

Study Record Updates

Last Update Posted (Estimated)

November 22, 2024

Last Update Submitted That Met QC Criteria

November 19, 2024

Last Verified

November 1, 2024

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • EK-Nr. 1941/2021

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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