The association between preoperative ROTEM-assessed hypercoagulability and postoperative pulmonary embolism in cytoreductive surgery and HIPEC: a single-site Bayesian analysis.

INTRODUCTION

Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) is associated with high rates of postoperative pulmonary embolism (PE). Rotational thromboelastometry (ROTEM) can detect hypercoagulability, but no consensus criteria exist in surgical populations. This study aimed to compare agreement between two ROTEM hypercoagulability definitions and their association with postoperative PE after CRS/HIPEC.

METHODS

We performed a retrospective cohort study enrolling CRS/HIPEC patients with baseline ROTEMs from July 2019 to July 2024. Hypercoagulability was defined using Hincker et al. criteria (elevated maximum clot formation in EXTEM, INTEM, or FIBTEM) and Thorson et al. criteria (broader ROTEM abnormalities). Primary outcomes were PE at 7 and 30 days postoperatively. Agreement between definitions was assessed using Cohen's kappa. Associations with PE were analysed using frequentist and Bayesian logistic regression, with inverse probability of treatment weighting to control confounding.

RESULTS

Of 137 patient-procedures, hypercoagulability was identified in 39% (Hincker) and 77% (Thorson) with poor agreement (κ = 0.219, p = 0.010). PE occurred in 11% at 7 days and 18% at 30 days. Frequentist analysis showed no significant associations due to insufficient power (maximum 30%). Bayesian analysis demonstrated consistently high posterior probabilities (98.9-100%) for increased PE risk in hypercoagulable patients, with risk ratios of 1.74-2.07 across both definitions and timeframes. Weighted analyses confirmed hypercoagulability as an independent risk factor.

CONCLUSION

ROTEM-defined hypercoagulability was independently associated with increased postoperative PE risk in CRS/HIPEC patients, based on Bayesian analyses. Poor agreement between definitions highlights the need for developing standardised criteria. Prospective validation is required before using these findings to guide clinical risk stratification.