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NCT Number: NCT05484830

Coagulation in Acute Aortic Dissection

Acute aortic dissection (AAD) involving the ascending aorta (Stanford classification type A) remains a life-threatening disease. Excessive perioperative bleeding requiring massive transfusion of allogeneic blood products, and surgical reexploration remain major challenges in these patients. Previous research has indicated that patients with AAD show pronounced haemostatic alterations prior to surgery which are aggravated during major aortic surgery with cardiopulmonary bypass and hypothermia full heparinization.

Intensified anticoagulation management guided by heparin dose response (HDR) calculation, and repeated measurement of heparin concentration may be more effective than standard empiric weight-based heparin and protamine management monitored by activated clotting time (ACT) measurements to suppress thrombin generation during surgery for AAD.

This randomized controlled clinical trial compares the impact of two recommended anticoagulation management strategies during surgery for AAD including deep hypothermia on activation of coagulation: Heparin/protamine-management based on HDR-titration by means of HMS Plus® versus current institutional standard (HDR- versus ACT-approach).

Primary endpoint is thrombin generation as measured by early postoperative prothrombin fragment 1+2 (F1+2). Secondary endpoints are other markers of coagulation and fibrinolysis as well as clinical outcome.

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Key information

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Aarhus University Hospital Skejby

Aarhus, 8200, Denmark

About this study

Hypotheses:

Primary: HDR-approach is superior to ACT-approach in terms of suppressing thrombin generation after emergent surgery for acute aortic dissection (Stanford type A).

Secondary: HDR-approach is superior with regard to

  • early postoperative haemostatic capacity
  • requirement of blood product transfusion and haemostatic agents
  • postoperative bleeding

Design:

Investigator-initiated, single-site, parallel-group (1:1), prospective, randomized, partially double-blinded trial in patients undergoing emergent surgery for acute aortic dissection comparing two heparin management strategies with superiority design. Prior to randomization, patients are stratified according to preoperative organ dysfunction and anticoagulation therapy.

Acute research study design as patients with acute aortic dissection are considered incompetent according to the Danish Research Ethics Committees definition. Deferred consent by the competent patient or her/his proxy (next of kin) and an independent physician) is used. 26 consecutive patients undergoing emergent surgery for acute aortic dissection (Stanford type A) are randomized 1:1 into the following heparin management strategies with an ACT target of 480 seconds:

  • Individualised HDR-approach
  • Conventional ACT-approach

No interim analysis. A sub-study to compare cost-benefit of both strategies is planned.

Who can participate

Healthy volunteers accepted: No

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

Inclusion criteria

  • Age > 18 years
  • Emergent Acute Aortic Dissection with cardiopulmonary bypass
  • Incapable of providing informed consent

Exclusion criteria

  • History of congenital coagulation disorder (haemophilia)
  • Previous open cardiac surgery
  • Death during induction of anaesthesia

Treatment and study plan

Individualized HDR-approach

Procedure

Heparin concentration necessary to achieve target ACT > 480 sec. calculated based on individual HDR-curve.

If HDR slope ˂80 s/IU/mL (reduced sensitivity to heparin), 1000 IU of AT concentrate (Antitrombin III "Baxalta"®, Takeda Pharma, Vallensbæk Strand, DK). Whole blood concentration of circulating heparin assessed by heparin assays. Additional heparin given as required. After weaning, protamine necessary to reverse circulating heparin calculated according to heparin-protamine titration measurement. After protamine, heparin reversal evaluated with low-range heparin-protamine titration cartridge and additional protamine given as required.

Conventional ACT-approach

Procedure

Initial Heparin 400 IU/kg (500 IU/kg if treated with heparin prior to surgery). ACT Assessment with Hemochron® Signature Elite (ITC, International Technidyne Corp., Edison, NJ, USA).

Additional heparin until ACT > 480 sec. If ACT < 480 sec. after despite repeated heparin supplement with 1000 IU of AT III concentrate. Target ACT > 480 sec. during normothermic CPB, and target ACT > 700 seconds during hypothermia After weaning, protamine 10mg/mL (0.7 mg of protamine/ 100 IU total heparin administered). Heparin reversal is evaluated with an activated partial thromboplastin (APTT). If APTT > 40 seconds, additional protamine (25-50 mg i.v.).

Primary outcomes

  1. F1+2

    Time frame: up to 2 days after surgery

    Prothrombin fragment 1+2 (pmol/L)

Secondary outcomes

  1. TAT

    Time frame: up to 2 days after surgery

    Thrombin-Antithrombin Complex (ug/L)

  2. ETP

    Time frame: up to 2 days after surgery

    Endogenous Thrombin Potential (nmol/L x min)

  3. Thrombin time

    Time frame: up to 2 days after surgery

    High-dose thrombin time (sec)

  4. Antithrombin

    Time frame: up to 2 days after surgery

    (kIU/L)

  5. D-dimer

    Time frame: up to 2 days after surgery

    D-dimer (mg/L)

  6. Clot lysis

    Time frame: up to 2 days after surgery

    Clot lysis

  7. Heparin sensitivity

    Time frame: prior to surgery

    Heparin sensitivity (slope)

  8. Heparin (total)

    Time frame: immediately after surgery

    Total amount of heparin

  9. Protamin (total)

    Time frame: immediately after surgery

    Total amount of protamin

  10. Ratio

    Time frame: immediately after surgery

    Protamin/heparin ratio

  11. Resistance

    Time frame: immediately after surgery

    Heparin resistance

  12. Blood cell-saver

    Time frame: immediately after surgery

    Volume of blood processed in cell-saver (mL)

  13. Blood loss sponges

    Time frame: immediately after surgery

    Gravimetric estimation of intraoperative blood loss (calculation based on the change between dry and blood-soaked sponges, accounting for irrigation) in mL

  14. Drain output

    Time frame: 48 hours after surgery

    Total mediastinal drain output (ml)

  15. Blood tranfusion

    Time frame: 48 hours after surgery

    Tranfusion of blood products (units): Red blood cells, fresh frozen plasma, platelet concentrates

  16. Fibrinogen

    Time frame: 24 hours after surgery

    Administration of fibrinogen concentrate (mg)

  17. PCC

    Time frame: 24 hours after surgery

    Administration of prothrombin complex concentrate (Octaplex) (IU)

  18. AT concentrate

    Time frame: 24 hours after surgery

    Administration of Antithrombin concentrate (IU)

  19. Cryoprecipitate Plasma

    Time frame: 24 hours after surgery

    Administration of cryoprecipitate plasma

  20. Recombinant FVIIa

    Time frame: 24 hours after surgery

    Administration of Recombinant FVIIa

  21. 2. Closure

    Time frame: 30 days after surgery

    Secondary closure

  22. Reoperation for bleeding

    Time frame: 30 days after surgery

    Reexploration for bleeding (yes/no)

  23. Protocol violation

    Time frame: immediately after surgery

    Protocol violation (yes/no)

  24. Mortality

    Time frame: up to 90 days after surgery

    All-cause mortality

  25. Stroke

    Time frame: 30 days after surgery

    Stroke (yes/no)

  26. Myocardial infarction

    Time frame: 30 days after surgery

    Perioperative myocardial infarction (yes/no)

  27. Renal

    Time frame: 30 days after surgery

    Requirement of continuous renal replacement therapy (yes/no)

  28. Low cardiac output syndrome

    Time frame: 30 days after surgery

    Low cardiac output syndrome requiring inotropics or mechanical support (yes/no)

  29. Vascular malperfusion

    Time frame: 30 days after surgery

    Visceral og peripheral vascular malperfusion requiring surgical or percutaneous intervention

  30. Intraop. coagulation

    Time frame: Immediately after surgery

    Clinical signs of coagulation during CPB (yes/no)

  31. Length of surgery

    Time frame: 30 days after surgery

    minutes

  32. Length of stay ICU

    Time frame: 30 days after surgery

    days

  33. Length of hospitalization

    Time frame: 30 days after surgery

    Hospitalization (days)

Sponsors and collaborators

Lead sponsor

Ivy susanne Modrau, MD

Other

Registry information

Official study title

Impact of Anticoagulation Management on Thrombin Generation During Surgery for Acute Aortic Dissection

Acronym: CAAD

Important dates

Study start
2022
Primary completion
2024
Study completion
2024
First posted
Aug 2, 2022
Registry last updated
Jul 18, 2025

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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