Deep vein thrombosis and pulmonary embolism following cytoreductive surgery and HIPEC for PMP of appendiceal origin.

OBJECTIVES: Thromboembolic events (TEE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), are important causes of morbidity after major surgery. Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) may carry particularly high risks. We evaluated TEE incidence following CRS-HIPEC for pseudomyxoma peritonei (PMP) of appendiceal origin. METHODS: A retrospective analysis of prospectively collected data (2020-2024) was performed in a high-volume peritoneal malignancy centre. Routine duplex ultrasound on postoperative day 10 screened for DVT. CT pulmonary angiography (CTPA) was performed in symptomatic patients to assess for PE. Demographics, prior surgery, peritoneal cancer index (PCI), operative duration, cryoprecipitate transfusion, postoperative complications, and tumour histopathology were recorded. Univariate analyses used the Mann-Whitney U test and Pearson's chi-square test. RESULTS: In total, 1.180 patients underwent CRS and HIPEC, including 710 with an appendiceal primary, of whom 554 had PMP. TEE occurred in 63/554 (11.4%), including 41 PE (7.4%) and 22 DVT (4.0%). Median time to diagnosis was 8 days for PE and 11 days for DVT. DVT was associated with greater cryoprecipitate use (p = 0.002, OR 1.4) and high-grade appendiceal mucinous neoplasm (HAMN) (p = 0.027, OR 2.5). Most PEs were peripheral (37/41; 90.2%). PE was more common in males (11.1% vs. 5.2%; p = 0.010, OR 2.3) and associated with higher PCI (p = 0.017, OR 2.3). CONCLUSIONS: TEE is frequent and under-reported after CRS and HIPEC for PMP. PE often develops early, is predominantly peripheral, and may occur independently of DVT. Male sex, high PCI, cryoprecipitate transfusion, and HAMN histology were significant risk factors.