Comparison of ICG Microangiography and Conventional Angiography in Severe Frostbite

February 22, 2024 updated by: HealthPartners Institute

Prospective Comparison of ICG Microangiography and Conventional Angiography in Severe Frostbite

Severe frostbite injury is a significant cause of morbidity in northern climates. Minnesota has some of the highest numbers of severe frostbite injuries in North America. As a result, Regions Hospital has the best opportunity to study this disease process and improve outcomes for frostbite patients. The diagnostic methods for severe frostbite injury vary from institution to institution and there is no standard practice. Commonly utilized methods include conventional angiography, Technetium 99 triple phase bone scans, SPECT studies, Indocyanine Green microangiography, and doppler studies. The proposed pilot study aims to directly compare conventional angiography imaging to ICG microangiography in adult patients with severe frostbite. Severe frostbite is defined as 4th degree: frostbite resulting in vascular occlusion and tissue ischemia. Both imaging modalities have been used for the diagnosis and monitoring of severe frostbite injury but there has never been a study directly comparing these two imaging modalities.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

Frostbite injury has been a significant cause of morbidity and mortality for as long as humans have experienced cold winters. When frostbite occurs, there are two primary mechanisms through which tissue damage occurs, though the main mechanism focused on here is systemic cooling. Frostbite is a multiphase process that starts with systemic cooling. As the body cools, blood is shunted from the extremities to the core to maintain heat in the vital organs. During this shunting, there is extensive vasospasm in the extremities and the tissue becomes ischemic. Upon further cooling, tissue ice crystals form within the cells and interstitial spaces causing desiccation and cell destruction. This occurs in the soft tissues and also affects the endothelium of the micro- and macro-vasculature. Clots form in the microvasculature, worsening the ischemia. All ischemic tissues release pro-inflammatory factors, which increase inflammation and worsen clotting.

Upon rewarming of the frozen tissues, the reperfusion can worsen the inflammatory state as these factors released by the ischemic tissue are now able to circulate. Rapid rewarming is used as a tool to mitigate this reperfusion injury, but it does not eliminate the damage. After rapid rewarming, the tissue is assessed for the extent of damage to determine next treatment steps. Diagnosis varies by institution, but the main goal of all diagnostic modalities is to determine if there is a vascular cutoff causing tissue ischemia.

At Regions Hospital, the main diagnostic method that has been used for over 20 years is conventional angiography. This clearly demonstrates the microvasculature of the tissues and allows the intra-arterial catheter directed sheaths to be placed to start thrombolytics, heparin, and vasodilators to treat the tissue ischemia. Other diagnostic modalities used elsewhere include Technetium 99 triple phase bone scans, SPECT imaging, and indocyanine green (ICG) microangiography. All of these imaging modalities demonstrate the perfusion of the affected tissue but do not allow for directed delivery of thrombolytics. In institutions that use these imaging techniques, thrombolytics are typically delivered in an intravenous fashion rather than intra-arterial.

ICG microangiography is a technology that has had rapidly expanding applications in recent decades. These have included retinal imaging, determining perfusion of colorectal anastomoses, biliary imaging, and assessing the blood supply of tissue flaps. It has recently been used in diagnosis of frostbite with good correlation with severe final amputation levels. It is easy to use, non-radiating, can be performed at the bedside, and cheaper than other imaging modalities.

Given that every hospital has different diagnostic and treatment algorithms, these different imaging modalities have rarely been compared in the same patient. The current best metric is comparing the imaging modality with the amount of tissue that is amputated as demonstrated in prior studies cited here. This research application provides a unique opportunity to compare two imaging modalities head-to-head in the same patient and determine their concordance or discordance.

Study Type

Observational

Enrollment (Estimated)

20

Contacts and Locations

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

Study Contact

Study Locations

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

Sampling Method

Non-Probability Sample

Study Population

Patients undergoing conventional angiography and thrombolysis for severe frostbite. will be identified by the burn surgeons and advance practice practitioners. They will evaluate the patients to determine whether they meet the inclusion/exclusion criteria of the study.

Description

Inclusion Criteria:

  1. Adult (>18 years old) patients
  2. Diagnosed with severe frostbite by conventional angiography
  3. Undergoing thrombolysis with catheter directed lytics
  4. Clinically sober at the time of consent
  5. Cognitively able to provide consent as determined by clinician's best judgement
  6. Normal kidney function (GFR >60)

Exclusion Criteria:

  1. Pregnant. Pregnancy will be determined by standard of care pregnancy test performed on all female frostbite patients who are receiving lytics.
  2. Iodine allergy.

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

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Assessment of Angiography and ICG microangiography imaging demonstrating ischemic tissue present in severe frostbite scored by Hennepin Frostbite Score.
Time Frame: Through study completion, an average of 2 years
Hypothesize that these two imaging modalities (ICG (indocyanine green) and conventional angiography) will be concordant at demonstrating the ischemic tissue present in severe frostbite.
Through study completion, an average of 2 years

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Safety of indocyanine green when delivered in close association with contrast dye (used in conventional angiography) measured by number of adverse events
Time Frame: Through study completion, an average of 2 years
Contrast dye used in conventional angiography is associated with nephrotoxicity and other risks. Indocyanine green dye is generally considered to be a highly safe product with minimal risks associated with administration. It has been used for decades with minimal side effects. It is hypothesized that ICG dye will not result in any increase in risk to the patient when delivered in temporal proximity to conventional dye.
Through study completion, an average of 2 years

Collaborators and Investigators

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

Investigators

  • Principal Investigator: Alexandra Lacey, MD, Regions Hospital

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 3, 2023

Primary Completion (Estimated)

March 31, 2025

Study Completion (Estimated)

March 31, 2025

Study Registration Dates

First Submitted

January 14, 2023

First Submitted That Met QC Criteria

March 8, 2023

First Posted (Actual)

March 21, 2023

Study Record Updates

Last Update Posted (Estimated)

February 26, 2024

Last Update Submitted That Met QC Criteria

February 22, 2024

Last Verified

February 1, 2024

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • A22-321

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

Yes

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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