Session: 311. Disorders of Platelet Number or Function: Poster II
Hematology Disease Topics & Pathways:
This is a single institution retrospective chart review of all patients between 2017-2019 who underwent CABG surgery. A total of 165 patients were studied and the patients who had HIT workup done were selected for further evaluation. Patient charts were reviewed to document initial platelet counts and post-CABG surgery platelet counts. Platelet counts were followed and documented for up to post-op day #15, if available. Review also included identification of new cases of arterial or venous thrombosis. For each patient that had HIT work-up, the HIT probability score was calculated by three different methods (4T score, HEP score, and LLL score). Sensitivity and specificity of the scoring systems was calculated. ANOVA test was used to determine if there was a difference between the three scoring systems and paired T-test was used to assess between the scoring systems.
A total of 37 patients were studied and paired-T tests were used to compare between the scoring systems. There were a total of 6 patients with confirmed HIT based on a positive serotonin release assay (SRA) and 31 patients who had a negative work-up for HIT. The PPV of 4T, HEP, LLL was 0.545, 0.545, 0.667 respectively. Specificity was highest for LLL model: 0.912 and 0.861 for both HEP and 4T. ANOVA test determined in patients with a definitive HIT diagnosis that there was no difference among the 3 tests (p value=0.47792); however there was a difference between the scoring systems when the patients tested negative for HIT (p value= 0.00001). Furthermore, when individually comparing LLL to either 4T or HEP there was a significant difference in both true HIT and non-HIT patients p-value <0.03.
These findings suggest that LLL is a better predictor of HIT in patients with CABG and it is especially superior in ruling out HIT in comparison to 4T and HEP. This further goes to support using LLL over 4T score in patients with CABG to help improve predictability of HIT. LLL is a simple calculation similar to 4T score and hence we should utilize it more often in our CABG patients.
Disclosures: No relevant conflicts of interest to declare.
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