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NCT Number: NCT07028372

Long Term Follow-up of Cardiac Arrest Survivors Exposed to Ultra-rapid Cooling

Less than 10% of patients eliciting out-of-hospital cardiac arrest (OHCA) survive, although 30% can be resuscitated by Emergency services before admission in Intensive Care Units (ICU). The majority succumb to Post-Cardiac Arrest Syndrome (PCAS). PCAS is associated with high mortality (60-70%) and morbidity.

One proposed method of preventing the neurological and cardiac consequences of PCAS is to lower the body temperature to 33°C as quickly as possible. This approach is known as therapeutic hypothermia or Targeted Temperature Management (TTM). The Vent2Cool system, developed by Orixha, is a novel approach that enables the rapid induction of therapeutic hypothermia by using hypothermic Total Liquid Ventilation (TLV) to reach a protective temperature of 33°C within minutes.

The OverCool feasibility study, which started in April 2025, is designed to validate the clinical performance and safety of an ultra-rapid cooling approach combining ultra-rapid hypothermia induction using the Vent2Cool system, and maintenance and rewarming using the ArcticSun system.

The AfterCool study aims to evaluate long-term outcomes during a five-year follow-up of cardiac arrest survivors who were treated with ultrarapid cooling in the OverCool study.

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Key information

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

Angers University Hospital, Medical Intensive Care Unit, Vent'Lab, Angers, France

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About this study

Fewer than 10% of patients experiencing out-of-hospital cardiac arrest (OHCA) survive, although 30% can be resuscitated by emergency services before being admitted to intensive care units (ICUs). Many cardiac arrest patients who are initially resuscitated by first responders and/or EMS, however, are condemned to a 'second death' in the ICU due to severe neurological and multi-visceral sequelae from post-cardiac arrest syndrome (PCAS).

One proposed method of preventing the neurological and cardiac complications of PCAS is to lower the body temperature to 33°C as quickly as possible. This approach is known as therapeutic hypothermia or Targeted Temperature Management (TTM). However, the cooling power of available technologies is insufficient to induce therapeutic hypothermia, and they do not improve outcomes for most patients. Conversely, experimental reports clearly demonstrate that therapeutic hypothermia can dramatically improve clinical outcomes if applied within two to three hours of resuscitation.

The devices currently available for TTM are mostly external cooling devices, such as blankets, pads and suits. These devices have a cooling performance of less than 1°C per hour in the body's core and in vital organs with high blood flow. Orixha's Vent2Cool is a novel approach that enables the induction of ultra-rapid therapeutic hypothermia (URTH) by using hypothermic total liquid ventilation (TLV) to reach a protective temperature of 33°C within minutes.

The OverCool feasibility study, which has been approved by the French authorities and began enrolment in early 2025, is designed to test the feasibility of ultra-rapid cooling. It aims to validate the clinical performance and safety of an ultra-rapid cooling approach combining ultra-rapid hypothermia induction using the Vent2Cool system, and maintenance and rewarming using the ArcticSun system. OverCool will pave the way for other clinical investigations to demonstrate the superior clinical benefits of this new approach to hypothermic TTM compared to the standard of care.

The AfterCool study will follow cardiac arrest survivors who were treated with ultrarapid cooling in the Overcool study for five years. The AfterCool approach aligns with the need to evaluate long-term outcomes after cardiac arrest, as endorsed by the French AfterROSC network, which supports research into post-cardiac arrest patients.

Eligible subjects, after having received clear, impartial and complete information, and not having objected to participation in the study, will be included. At the inclusion visit, a detailed questionnaire regarding life status, quality of life, putative rehospitalization, cardiovascular, neurological and respiratory status will be administered.

At 6±1 months and 12±1 months after inclusion, and then yearly during a total period of 5 years, the patients or trusted persons or the close relatives or parents will be interviewed by phone, using the same questionnaire regarding life status, quality of life, putative rehospitalization, cardiovascular, neurological and respiratory status.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age of 18 years and over
  • Cardiac arrest patient included in and alive at the end of the OverCool clinical investigation (28 days after the cardiac arrest)
  • Non-opposition from the patient or the trusted person or the close relative or parent obtained within 3 months after the end of the OverCool study

Exclusion criteria

  • Follow-up refusal from patient of trusted person or the close relative or parent
  • Having being included in the OverCool clinical investigation but not submitted to the Vent2Cool procedure
  • Impossibility to reach the patient or the trusted person or the close relative or parent

Treatment and study plan

Short Form Health Survey (SF-36)

Other

Heath-related quality-of-life is assessed using the SF-36 questionnaire, which is administered at the inclusion visite, then at month 6, year 1, year 2, year 3, year 4 and year 5, in the form of a telephone interview.

Modified Rankin Score (mRS)

Other

The degree of disability/dependence is evaluated using the mRS scale at the inclusion visite, then at month 6, year 1, year 2, year 3, year 4 and year 5, via telephone interview.

Activity of Daily Living (ADL) questionnaire

Other

Level of independence is evaluated using the ADL questionnaire, which is administered at the inclusion visite, then at month 6, year 1, year 2, year 3, year 4 and year 5, in the form of a telephone interview.

New York Heart Association (NYHA) Classification

Other

The extent of heart failure is assessed using the NYHA functional classification at the inclusion visite, then at month 6, year 1, year 2, year 3, year 4 and year 5, via telephone interview.

St George's Respiratory Questionnaire (SGRQ)

Other

Respiratory status is assessed using the SGRQ questionnaire at the inclusion visite, then at month 6, year 1, year 2, year 3, year 4 and year 5, via telephone interview.

Primary outcomes

  1. Life status at 5 years

    Time frame: 5 years

    The primary endpoint is the life status at 5 years assessed by phone interview. Whenever possible, life status will be confirmed by reviewing the medical record.

Secondary outcomes

  1. Suspected cause of death

    Time frame: 5 years

    The suspected cause of death in the event of a death. Data are collected via interview. If the deceased is rehospitalised or receives additional care in a hospital that shares a medical database with centres participating in the Aftercool study, the information will be confirmed by reviewing the medical record.

  2. Rehospitalization

    Time frame: 5 years

    Data are collected via interview. If a participant is rehospitalised or requires additional hospital care, and if that hospital shares a medical database with the centres of the Aftercool study, the information will be confirmed by reviewing the medical record.

  3. Modified Rankin Scale (mRS) Score

    Time frame: Baseline, 6 months, 1 year, 2 years, 3 years, 4 years and 5 years

    The mRS scale is used to assess neurological status. mRS scale ranges from 0 (no residual symptoms) to 6 (dead). Higher scores indicate greater disability.

  4. 36-Item Short Form Health Survey (SF-36) score

    Time frame: Baseline, 6 months, 1 year, 2 years, 3 years, 4 years and 5 years

    The SF-36 questionnaire is a health-related quality of life scale, comprising eight scaled scores: vitality, physical functioning, bodily pain, general health perceptions, physical role functioning, emotional role functioning, social role functioning and mental health. Scores range from 0 - 100. Higher scores mean less disability.

  5. Activity of Daily Living (ADL) score

    Time frame: Baseline, 6 months, 1 year, 2 years, 3 years, 4 years and 5 years

    Autonomy level is measured using a six-item ADL scale. Scores range from 0 (the patient is very dependent) to 6 (the patient is independent).

  6. Cardiovascular adverse events

    Time frame: Baseline, 6 months, 1 year, 2 years, 3 years, 4 years and 5 years

    Cardiovascular adverse events that occurred between interviews: acute coronary syndromes, arrhythmias, stroke or other cerebrovascular events.

  7. NewYork Health Association (NYHA) status

    Time frame: Baseline, 6 months, 1 year, 2 years, 3 years, 4 years and 5 years

    The extent of heart failure is assessed using The New York Heart Association (NYHA) Functional Classification. It enables patients to be classified into classes I to IV according to their symptoms, with class I corresponding to the best health.

  8. Respiratory adverse events

    Time frame: Baseline, 6 months, 1 year, 2 years, 3 years, 4 years and 5 years

    Respiratory adverse events that occurred between interviews.

  9. St-George's Respiratory Questionnaire (SGRQ) Score

    Time frame: Baseline, 6 months, 1 year, 2 years, 3 years, 4 years and 5 years

    The SGRQ questionnaire (PDF) has 50 items divided into three parts measuring symptoms, activity limitation and social and emotional impact of disease. Scores range from 0 to 100, with higher scores indicating more limitations

  10. Home oxygen therapy

    Time frame: Baseline, 6 months, 1 year, 2 years, 3 years, 4 years and 5 years

    The need to resort to the use of home oxygen therapy between interviews.

Study contacts

Contact information is provided by the study sponsor or research team.

Alain CARIOU, MD PhD

CONTACT

[email protected]

+33 1 58 41 25 01

Sponsors and collaborators

Lead sponsor

Assistance Publique - Hôpitaux de Paris

Other

Collaborators

  • ORIXHA

Registry information

Official study title

Long Term Follow-up of Cardiac Arrest Survivors Exposed to Ultra-rapid Cooling, a Prospective Non-interventional Cohort

Acronym: AFTERCOOL

Important dates

Study start
2025
Primary completion
2031
Study completion
2031
First posted
Jun 19, 2025
Registry last updated
Mar 24, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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