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Predictive value of blood clotting tests in cardiac surgical patients

G P Gravlee1, S Arora, S W Lavender

  • 1Department of Anesthesia, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, North Carolina.

The Annals of Thoracic Surgery
|July 1, 1994
PubMed

Insights

Routine clotting tests after cardiac surgery, including activated clotting time and prothrombin time, show statistically significant but low predictive value for postoperative blood loss. These tests are not recommended for routine screening in these patients.

Area of Science:

  • Cardiovascular Surgery
  • Hematology
  • Clinical Pathology

Background:

  • Postoperative bleeding is a significant complication following cardiac surgery.
  • Accurate prediction of bleeding risk is crucial for patient management.

Purpose of the Study:

  • To prospectively evaluate the predictive value of various clotting function tests for postoperative mediastinal drainage in adult cardiac surgical patients.

Main Methods:

  • Prospective evaluation of 897 adult cardiac surgery patients.
  • Inclusion of tests: activated clotting time, activated partial thromboplastin time, prothrombin time, thrombin time, fibrinogen, fibrin/fibrinogen degradation products, platelet count, and Duke's earlobe bleeding time.
  • Multivariate analysis incorporating patient demographics and cardiopulmonary bypass duration.

Main Results:

  • Statistically significant correlations were identified between 16-hour mediastinal drainage and several clotting tests.
  • Despite statistical significance, scatter plots revealed weak correlations with limited predictive value.
  • The best multivariate model explained only 12% of the variation in postoperative blood loss.

Conclusions:

  • Current clotting function tests have low predictive value for postoperative blood loss after cardiac surgery.
  • Routine screening of patients with these tests post-cardiopulmonary bypass is not clinically sensible.

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