Pulmonary Embolism Calculator May Identify Risk Not Captured at Discharge After Surgery

Dallal RM, Riggio J, Li M, Eraso LH, et al. Targeting Extended Thromboprophylaxis after Surgery Through Multidimensional Dynamic Pulmonary Embolism Risk Assessment: Development and Temporal Validation in 4.8 Million Operations. J Am Coll Surg. June 2026.

Extended thromboprophylaxis reduces postoperative venous thromboembolism but is inconsistently used because pulmonary embolism (PE) risk varies across operations and may change after discharge. Dallal et al developed and temporally validated a two-stage calculator to estimate PE risk at discharge and updated that assessment risk after unplanned readmission or reoperation.

ACS-NSQIP adult operations from 2020–2023 were used for development (n = 3,864,605), with 2024 operations reserved for temporal validation (n = 956,434). The primary outcome was 30-day postoperative PE. Penalized logistic regression modeled discharge risk using patient, surgical, and early postoperative variables; dynamic reassessment added the timing of the first unplanned readmission or reoperation. A prespecified predicted-risk threshold of 0.5% was evaluated.

Among 4,856,597 operations, 17,045 patients developed PE (0.35%). In temporal validation, the discharge model demonstrated an AUC of 0.811 (95% CI, 0.801–0.818), a calibration slope of 1.024, and an intercept of 0.036. Dynamic reassessment improved discrimination to an AUC of 0.892 (95% CI, 0.887–0.897), with a calibration slope of 0.991 and an intercept of 0.030. Among 57,840 patients with an unplanned-return event, reassessment moved 24,320 patients above the 0.5% treatment-consideration threshold despite being below the threshold at discharge. This newly flagged group had 711 observed PEs, a 2.92% PE rate, and one PE within 30 days for every 34.2 newly flagged patients under usual care. Sensitivity analyses indicated that the occurrence of an unplanned-return event, rather than the exact postoperative day, was the durable risk signal.

Across adult surgery, dynamic PE reassessment after unplanned readmission or reoperation identifies an actionable high-risk postoperative state not captured at discharge. This surgeon-facing calculator can make extended thromboprophylaxis reconsideration reproducible when prevention remains possible.