Evaluating Four HIT Prediction Scores After Cardiac Surgery With Cardiopulmonary Bypass: A Comparative Study

Area of Science:

• Cardiology
• Hematology
• Clinical Diagnostics

Background:

• Heparin-induced thrombocytopenia (HIT) is a serious immune complication of heparin therapy.
• Accurate diagnosis of HIT is crucial, especially in high-risk populations like cardiac surgery patients undergoing cardiopulmonary bypass (CPB).
• Clinical prediction scores are used to estimate HIT probability, but their performance in the CPB setting is not well-defined.

Purpose of the Study:

• To compare the diagnostic accuracy of four established clinical prediction scores for HIT.
• To evaluate the utility of these scores in adult patients who underwent cardiac surgery with CPB.

Main Methods:

• A bicentric retrospective observational study was conducted in France.
• Adult patients (2014-2021) who underwent cardiac surgery with CPB and were tested for HIT postoperatively were included.
• Diagnostic performance was assessed using receiver operating characteristic (ROC) curves and compared statistically.

Main Results:

• Among 283 patients, 19% were HIT-positive. Areas under the ROC curve for the 4Ts, HIT Expert Probability, cardiopulmonary bypass, and HFH scores ranged from 0.79 to 0.86, with no significant differences.
• Negative predictive values were high (94-96%), while positive predictive values were modest (31-49%).
• HIT-positive patients showed a biphasic platelet count pattern and higher mortality rates.

Conclusions:

• No single clinical probability score demonstrated superior diagnostic performance for HIT in cardiac surgery patients with CPB.
• These scores are most valuable as rule-out tools due to their high negative predictive performance.
• Further research is needed to develop and validate HIT diagnostic strategies specifically for the cardiac surgery population.