SurgCalc : PE

Postoperative PE, DVT, and VTE calculator

Bedside decision support for discharge risk assessment, triggered reassessment after sentinel events, and extended prophylaxis reference guidance.

Version 2026-03-30 v3 | Locked manuscript models + bedside simplification | N = 4,856,597

PE discharge AUC 0.811 | PE triggered reassessment AUC 0.892 | DVT discharge AUC 0.814 | VTE discharge AUC 0.811

Primary useDischarge PE risk
ReassessmentReadmission or reoperation
Data sourceACS-NSQIP 2020-2024
Support rolePublic informational tool

BMI Calculator

NSQIP BMI categories: <30 (reference) | 30–39.9 (Obese I–II) | 40–49.9 (Obese III) | 50+ (Super obese)
BMI = weight (kg) / height (m)². NSQIP records BMI as a continuous variable, binned into categories for the model.

Clinical Decision Support Tool

Risk estimates for CLINICAL DECISION SUPPORT only. NOT a substitute for clinical judgment. All decisions must incorporate individual patient factors, contraindications, bleeding risk, and clinical context.

Data: ACS-NSQIP PUF 2020-2024 (4.86M cases). Outcomes: postoperative PE, postoperative DVT, and composite VTE within 30 days. Model: locked logistic regression models with 2024 temporal validation (not FDA-cleared).

Public-use notice: This public calculator is intended for educational and clinical decision-support use. Do not enter direct patient identifiers such as name, date of birth, medical record number, address, phone number, or free-text notes.

Model Scope

  • Derived from ACS-NSQIP participating centers (2020-2024), all surgical specialties
  • Temporal validation: trained 2020-2023, tested 2024 (strict forward validation)
  • Primary discharge PE model AUC = 0.811 and triggered reassessment model AUC = 0.892 in 2024 validation
  • Secondary discharge DVT and VTE models are exported for clinician context, not to replace PE-focused decision making

Procedure Signal

  • Procedure complexity captured via locked work RVU spline terms plus pooled CPT-3 family
  • CPT code auto-populates work RVU and pooled CPT-3 family from the embedded CPT reference table
  • The bedside calculator omits functional status for usability, but the locked manuscript models retained it
  • If functional status is a major concern clinically, interpret the bedside estimate with added caution

Limitations

  • Does NOT model bleeding risk from anticoagulation
  • Predicted risk reflects observed NSQIP-era outcomes under prior care patterns and incompletely observed prophylaxis exposure
  • Low predicted risk does not necessarily equal low untreated biologic thrombosis risk
  • Not validated outside NSQIP-participating institutions
  • NOT FDA-cleared. Research and clinical decision support only.

Quick Start

1. Search the operation by CPT or plain-language name. 2. Enter the bedside variables available at discharge. 3. Use the PE estimate as the main decision signal; DVT and VTE are secondary context. If the patient is later readmitted or reoperated, move to the Reassessment tab. Do not enter patient identifiers. Not FDA-cleared.

Procedure

Type a CPT code or search by description. wRVU and CPT-3 family auto-populate.

Search by procedure name or CPT code. Only surgical procedures (wRVU ≥3.5) are shown — diagnostic/minor procedures are excluded.
wRVU: - CPT-3 Family: - Family volume: -

Patient Characteristics

Operative & Hospital Course

This bedside version intentionally omits functional status to reduce friction. The locked manuscript model retained functional status, but its incremental discrimination gain was negligible in ablation testing.

Discharge Risk Assessment

Primary decision modelPulmonary embolism
Best use caseAt discharge
If readmitted/reoperatedUse Triggered Reassessment.

Step 1: Sequential Workflow

Every patient receives this discharge risk estimate. If the patient is later readmitted or undergoes reoperation, proceed to the Triggered Reassessment tab for an updated estimate that accounts for these sentinel events and their timing from the index operation.

Risk Tiers (PE-Specific, NSQIP)

  • Low (<0.15%): Standard perioperative VTE prophylaxis; routine discharge education.
  • Moderate (0.15-0.34%): Consider patient-specific extended prophylaxis; closer follow-up.
  • High (0.35-0.99%): Extended prophylaxis strongly recommended unless contraindicated.
  • Very High (≥1.0%): Highest risk tier. Extended prophylaxis + early follow-up essential.

Triggered Reassessment

Switch to "Triggered Reassessment" tab if any post-discharge event occurs:

  • Readmission for any reason (POD timing matters)
  • Reoperation for any reason
  • Readmission POD 0-3: OR = 21.8 for PE (rate 2.87% vs baseline 0.170%)

Postoperative DVT Risk

Composite VTE Risk

What to do next

Clinical Summary

Triggered Reassessment Model

Recalculates PE risk after sentinel post-discharge events. Readmission timing is the single strongest risk signal (OR up to 21.8). Reoperation timing changes risk further.

Model: Validated AUC = 0.892 in 2024 temporal validation. Uses the same locked baseline/procedure backbone as the discharge PE model plus readmission and reoperation timing.

Public-use notice: This public calculator is intended for educational and clinical decision-support use. Do not enter direct patient identifiers or free-text patient information.

When to use this reassessment model

Use this tab only after a new post-discharge sentinel event, especially readmission or reoperation. It reassesses the PE estimate after the clinical course changes and should not replace the original discharge calculation. Do not enter patient identifiers. Not FDA-cleared.

Step 2: Triggered Reassessment (After Sentinel Event)

This model is used only after a sentinel event — unplanned readmission or reoperation. It reassesses PE risk using the same patient and procedural variables plus sentinel-event timing. Among patients who experience a sentinel event, 42% cross the 0.5% risk threshold for the first time — patients who would not have been flagged at discharge. Early readmission (POD 0-3) carries an OR of 21.8 for PE, representing substantial risk amplification.

Patient & Operative Characteristics

Enter CPT code to reuse the same procedure signal used in the locked discharge PE model, or copy values from the Discharge tab.

wRVU: - CPT-3 Family: -

Triggered Reassessment

These are the sentinel-event timing variables. Select timing relative to the index operation.

The reassessment model remains PE-only. DVT and composite VTE are currently exported as discharge-stage secondary models, not post-discharge reassessment models.

Reassessed Risk Summary

Primary decision modelPulmonary embolism
TriggerReadmission / reoperation
Use afterClinical change

Interpretation

The reassessment model captures the substantial risk amplification from post-discharge sentinel events. Readmission within POD 0-3 carries an OR of 21.8 for PE.

Patients with early readmission + reoperation represent the highest-risk subgroup and should receive extended prophylaxis unless actively bleeding.

Risk reclassification: Compare this reassessed risk to the original discharge estimate. Patients below the 0.5% threshold at discharge who cross above it after a sentinel event represent newly identified high-risk patients who may benefit from intensified VTE prevention.

What to do next

Clinical Summary

This Patient's Estimated PE Risk Is Elevated

Based on the calculated risk, extended-duration pharmacologic prophylaxis should be strongly considered. Review the options below, weigh bleeding risk, and individualize the decision.

Bedside Essentials

This tab is intentionally organized for fast clinical use. If the patient is high risk for PE and does not have a major bleeding contraindication, the simplest default path is enoxaparin 40 mg subcutaneously once daily for 28 days total, adjusted for renal function and possibly extreme obesity.

  • Use this guidance when the calculator suggests elevated PE risk and the patient is otherwise a reasonable prophylaxis candidate.
  • Do not treat the risk estimate as a bleeding model. Bleeding risk, neuraxial anesthesia, and surgeon preference still matter.
  • If injections are not feasible and bleeding risk is acceptable, oral options may be considered, but the evidence base is weaker and more context-dependent.
Medications & Dosing Postop Timing Contraindications Bleeding Risk Guideline Summary

Extended Prophylaxis Medications

Extended-duration thromboprophylaxis (ETP) refers to pharmacologic VTE prevention continued beyond the inpatient stay, typically 28-35 days total. The strongest evidence supports LMWH (enoxaparin) after major abdominal/pelvic and cancer surgery. DOACs are emerging alternatives with oral convenience but variable trial results. Contemporary data suggest the central question is patient selection: the 2025 CASCADE study reported post-discharge VTE rates of only 0.1%, underscoring the importance of identifying which patients truly benefit from extended prophylaxis rather than treating broadly.

Enoxaparin (Lovenox) LMWH STRONG EVIDENCE

Dose: 40 mg SC once daily
Duration: 28 days total (including inpatient days)
Renal adjustment: 30 mg SC daily if CrCl 15-30 mL/min; contraindicated if CrCl <15
Obesity adjustment: Consider 40 mg SC BID if BMI ≥40 or weight >150 kg (limited data)
Monitoring: Not routinely required; anti-Xa levels if renal impairment or extremes of weight
Extended LMWH prophylaxis consistently reduces postoperative VTE in higher-risk surgical populations. In earlier analyses, for every 14 patients who receive extended prophylaxis, one VTE event is prevented; for proximal DVT specifically, the ratio is 44 patients treated per event prevented. In CRC/IBD surgery, pooled data show LMWH ETP OR 0.18 (95% CI 0.07-0.50) for total VTE at 30d with no significant increase in major bleeding at 90d (Choi 2025).
Bleeding risk: ~2.5-fold increase in major hemorrhage in medical patients. In surgical patients (CRC/IBD), no significant increase in major bleeding (OR 0.25, 95% CI 0.03-2.24). Weigh against VTE reduction.

Rivaroxaban Direct Xa Inhibitor (DOAC) CONDITIONAL

Dose: 10 mg PO once daily
Duration: 28-35 days total
Renal adjustment: Avoid if CrCl <30 mL/min
Hepatic: Avoid in moderate-severe hepatic impairment (Child-Pugh B/C)
Interactions: Avoid combined use with strong CYP3A4/P-gp inhibitors (ketoconazole, ritonavir)
MAGELLAN (N=6024, medical): RR 0.77 for VTE at 35d (p=.02), but clinically relevant bleeding 4.1% vs 1.7% (RR 2.5; p<.001). Net clinical benefit NOT demonstrated. Surgical data (CRC): Rivaroxaban ETP OR 0.22 (95% CI 0.08-0.67) for total VTE at 30d; major bleeding OR 2.68 (95% CI 0.32-22.35) — wide CI (Choi 2025). Pooled LMWH+rivaroxaban ETP: OR 0.20 for VTE (p<0.0001).
MAGELLAN showed net harm in medical patients. Surgical (CRC) data more favorable but based on small trials. Oral convenience is the main advantage over LMWH.

Apixaban Direct Xa Inhibitor (DOAC) NEGATIVE TRIAL

Dose: 2.5 mg PO twice daily
Duration: 30 days
Renal adjustment: Standard dose; avoid if CrCl <15 mL/min
Note: NOT FDA-approved for extended VTE prophylaxis
ADOPT (N=4495, medical): Failed superiority vs enoxaparin for VTE (RR 0.87; 95% CI 0.62-1.23; p=.44). Significant increase in major bleeding (RR 2.58; 95% CI 1.02-7.24; p=.04). Underpowered — only 64% completed follow-up US. Not recommended for extended prophylaxis based on current evidence.
Negative pivotal trial. Use only if enoxaparin and rivaroxaban are both contraindicated, and only after careful bleeding risk assessment.

Dalteparin / Tinzaparin LMWH CONDITIONAL

Dalteparin: 5000 IU SC once daily
Tinzaparin: 4500 IU SC once daily (PERIOP-01 trial in CRC)
Duration: 28-56 days depending on surgery type and indication
Note: Often used interchangeably with enoxaparin in guidelines, though most RCT evidence is with enoxaparin
Tinzaparin (PERIOP-01, N=614, CRC): Major bleeding 0/307 (ETP) vs 2/307 (control) at 56d. Limited VTE data due to early closure. Generally extrapolated from enoxaparin trial data. ACCP 9th edition recommends any LMWH for extended prophylaxis.

Unfractionated Heparin (UFH) SQ Heparin CONDITIONAL

Dose: 5,000 units SC every 8 hours (preferred) or every 12 hours
Duration: Typically inpatient only; limited evidence for extended post-discharge use
Renal adjustment: No dose adjustment needed (not renally cleared) — preferred in severe renal impairment (CrCl <15 mL/min)
Monitoring: Platelet count at baseline and every 2-3 days (HIT surveillance). aPTT not needed for prophylactic dosing.
Reversal: Protamine sulfate (1 mg per 100 units UFH, max 50 mg)
ACCP 9th ed recommends LMWH over UFH for surgical prophylaxis (Grade 2B) based on superior bioavailability, once-daily dosing, lower HIT incidence, and more predictable pharmacokinetics. ASH 2018 medical guidelines: LMWH preferred over UFH. UFH remains appropriate when LMWH is unavailable or in severe renal failure.
Higher HIT risk (~1% with UFH vs <0.1% with LMWH). Requires TID dosing for optimal efficacy. Less predictable dose-response. Generally considered second-line to LMWH for extended prophylaxis. Main advantage: safe in severe renal impairment and fully reversible with protamine.

Warfarin (Coumadin) Vitamin K Antagonist CONDITIONAL

Dose: Variable; target INR 2.0-3.0. Typical starting dose 5 mg PO daily (2.5 mg in elderly, low weight, or hepatic impairment)
Duration: 28-35 days for extended prophylaxis; requires overlap with parenteral anticoagulant × 5 days and until INR ≥2.0 for 24h
Monitoring: INR at baseline, day 3, then every 2-3 days until stable; then weekly
Drug interactions: Extensive — CYP2C9/VKORC1 substrates, antibiotics, amiodarone, NSAIDs, many more
Diet: Consistent vitamin K intake required
Reversal: Vitamin K (PO or IV) + FFP or 4-factor PCC for emergencies
Well-studied for extended prophylaxis after TKA/THA (ACCP alternative, Grade 1B). Cochrane meta-analysis confirms efficacy but with higher monitoring burden. Largely supplanted by DOACs and LMWH for post-surgical prophylaxis due to narrow therapeutic index, drug/food interactions, and monitoring requirements.
Narrow therapeutic index. Requires frequent INR monitoring. Slow onset (3-5 days to therapeutic effect) necessitates bridging with heparin. Drug and dietary interactions are extensive. Best reserved for patients already on warfarin for another indication (AF, mechanical valve) or when LMWH/DOACs are contraindicated. Teratogenic — contraindicated in pregnancy.
When the Triggered Reassessment model identifies a patient above the treatment-consideration threshold (≥0.5% predicted PE probability), the clinician should weigh the evidence above in deciding whether to initiate or extend thromboprophylaxis. The model identifies candidates; the treatment decision incorporates bleeding risk, patient preference, and surgical context.
Postoperative Timing

When to Start Postoperative Anticoagulation

Timing of first prophylactic dose after surgery depends on procedure type, bleeding risk, and neuraxial anesthesia. Below are general guidance ranges — always defer to surgical team assessment of hemostasis.

Surgery TypeLMWH (First Dose)DOAC (First Dose)Notes
Major abdominal/pelvic (colorectal, hepatobiliary, gynecologic oncology) 6-12 hours postop Day 1-3 postop (varies by trial) ACCP: start LMWH 12h postop. Most RCTs began LMWH inpatient then extended. DOACs typically started after hemostasis confirmed.
Major orthopedic (TKA, THA, hip fracture) 12 hours postop 6-24 hours postop Strong evidence for 28-35 day prophylaxis. ACCP Grade 1B. Both LMWH and DOACs well-studied. Rivaroxaban/apixaban FDA-approved for TKA/THA.
Bariatric surgery 6-12 hours postop 24-48 hours postop Weight-adjusted dosing may be needed. Consider enoxaparin 40mg BID if BMI ≥40. Absorption of oral DOACs may be altered post-bypass — limited pharmacokinetic data.
Thoracic / lung resection 12-24 hours postop 24-48 hours postop Higher bleeding risk at chest tube sites. Often hold until chest tube output <200 mL/day. Extended prophylaxis less well-studied in this population.
Neurosurgery / spine 24-48 hours postop Caution — limited data Risk of epidural hematoma. Mechanical prophylaxis preferred initially. Pharmacologic start deferred 24-48h; some spine surgeons prefer 72h. Discuss with surgical team.
Vascular surgery 12-24 hours postop 24-48 hours postop Depends on graft type and anastomotic integrity. Avoid if active oozing from surgical site. Many patients already on therapeutic anticoagulation for PAD.
Cardiac surgery (CABG, valve) 24-48 hours postop 24-72 hours postop High baseline VTE risk but also high bleeding risk (mediastinal, pericardial). Extended prophylaxis rarely studied. Many patients transition to therapeutic anticoagulation for AF or mechanical valves.
After neuraxial anesthesia (epidural/spinal) Hold LMWH ≥4h after catheter removal Hold DOAC ≥6h after catheter removal ASRA guidelines: remove epidural catheter ≥12h after last LMWH dose; next dose ≥4h after removal. For DOACs, wait ≥6h after removal before dosing.
Key timing references: ACCP 9th ed (Falck-Ytter 2012, Chest 141:e278S-e325S) | ASRA 4th Consensus (Horlocker 2018, Reg Anesth Pain Med 43:263-309) | ASH 2019 Surgical VTE Prevention (Anderson 2019, Blood Adv 3:3898-3944)
Contraindications

Contraindications to Pharmacologic Prophylaxis

Absolute Contraindications

  • Active hemorrhage (surgical or non-surgical)
  • Heparin-induced thrombocytopenia (HIT) — for all heparins
  • Severe uncontrolled hypertension (SBP >200)
  • Intracranial hemorrhage within 24 hours
  • Coagulopathy: platelets <50K, INR >1.5 (untreated)
  • Epidural/spinal hematoma risk (indwelling neuraxial catheter)
  • Active intraocular bleeding
  • Known hypersensitivity to drug or excipients

Relative Contraindications (Weigh Risk/Benefit)

  • Platelets 50-100K
  • Recent GI bleed (within 3 months)
  • Hepatic impairment (INR >1.5 from liver disease)
  • CrCl 15-30 mL/min (dose-reduce LMWH; avoid most DOACs)
  • Body weight <50 kg (consider dose reduction)
  • Age >80 with multiple comorbidities
  • Concurrent antiplatelet therapy (aspirin + P2Y12 inhibitor)
  • Procedure with high reoperation risk
  • Active peptic ulcer disease (without recent bleed)

When pharmacologic prophylaxis is contraindicated, mechanical prophylaxis (intermittent pneumatic compression devices) should be used. Reassess daily for resolution of contraindication and convert to pharmacologic prophylaxis when safe.

Bleeding Risk Evidence

Bleeding Risk Assessment

Extended prophylaxis is a tradeoff: VTE reduction versus bleeding increase. The table below summarizes the risk-benefit data from major trials.

Agent / TrialVTE ReductionMajor Bleeding IncreaseNet Assessment
Enoxaparin (EXCLAIM, medical) ARR −1.53% (~1 VTE prevented per 65 treated) +0.51% (~1 major bleed per 196 treated) Favorable in Level 1 immobility; marginal in Level 2. ~2.5x bleeding increase.
Enoxaparin (LMWH ETP, CRC surgery pooled) OR 0.18 (0.07-0.50) OR 0.25 (0.03-2.24) at 90d — NS Strong VTE benefit, no significant bleeding increase. Favorable risk-benefit in CRC/IBD surgery.
Rivaroxaban (MAGELLAN, medical) RR 0.77 (0.62-0.96) RR 2.5 (1.85-3.25) Net clinical benefit NOT demonstrated. VTE benefit offset by significant bleeding harm.
Rivaroxaban (ETP, CRC surgery pooled) OR 0.22 (0.08-0.67) OR 2.68 (0.32-22.35) — NS, wide CI Promising VTE reduction. Bleeding data underpowered. Use with monitoring.
Apixaban (ADOPT, medical) RR 0.87 (0.62-1.23) — NS RR 2.58 (1.02-7.24) Failed efficacy + increased bleeding. NOT recommended for extended prophylaxis.
LMWH extended (THA/TKA, meta-analysis) 80% relative risk reduction for DVT No significant increase in major bleeding Gold standard for extended prophylaxis after major joint replacement. ACCP Grade 1B.
Key references: Tellor 2015 (J Pharm Tech 31:228-233) | Choi 2025 (Int J Colorectal Dis 40:211) | Eikelboom 2001 (Lancet 358:9-15) | Cochrane Review (Felder 2019, CD004318)
Guideline Summary

Guideline Recommendations for Extended Prophylaxis

ASH 2019 — Surgical Patients CONDITIONAL

Recommends pharmacologic over mechanical prophylaxis in surgical patients at high VTE risk with acceptable bleeding risk. 30 recommendations total. Emphasizes that not all surgery requires pharmacologic prophylaxis — the risk of VTE from surgery type and patient factors should be weighed against the bleeding potential. Extended-duration prophylaxis is supported after major abdominal/pelvic cancer surgery.
Anderson DR, Morgano GP, Bennett C, et al. Blood Adv. 2019;3(23):3898-3944.

ACCP / CHEST 9th Edition STRONG (Grade 1B)

Major orthopedic (TKA/THA/hip fracture): Extended prophylaxis × 35 days recommended (Grade 1B). LMWH preferred; DOACs (rivaroxaban, apixaban, dabigatran) acceptable alternatives.
Major abdominal/pelvic cancer surgery: Extended LMWH × 4 weeks recommended (Grade 1B).
Medical patients: Suggest against extending prophylaxis beyond hospital stay (Grade 2B) — except in specific high-risk subgroups.
Falck-Ytter 2012 (Chest 141:e278S-e325S) | Kahn 2012 (Chest 141:e195S-e226S) | Gould 2012 (Chest 141:e227S-e277S)

NICE 2018 — VTE Prevention STRONG

LMWH for 28-35 days after major hip or knee replacement. Extended LMWH for 28 days after major abdominal or pelvic surgery for cancer. Assess all hospital patients for VTE and bleeding risk within 14 hours of admission.
NICE NG89 (2018): Venous thromboembolism in over 16s.

ASCRS 2023 — Colorectal Surgery CONDITIONAL

For patients undergoing resection for CRC or IBD deemed high risk for VTE, extended thromboprophylaxis may be considered. Recommends Caprini score ≥9 as threshold for considering ETP. Acknowledges limited data on optimal agent, duration, and high-risk features specific to colorectal surgery.
Patel 2023 (Dis Colon Rectum 66:1162-73) | Carrier 2019 (Am J Surg 218:537-50)

ASH 2018 — Medical Patients CONDITIONAL

21 panel recommendations. For hospitalized medical patients at high VTE risk with acceptable bleeding risk, pharmacologic prophylaxis preferred over mechanical. LMWH preferred over UFH (once daily, fewer complications). Suggests against extending prophylaxis beyond discharge in most medical patients. Combined modalities (mechanical + pharmacologic) not necessary in most cases.
Schünemann HJ et al. Blood Adv. 2018;2(22):3198-3225.

Reference Guidance Only

This section does not prescribe treatment. The information below summarizes published guideline and trial data for bedside reference.

Reference content prepared and reviewed by Ramsey M. Dallal, MD (site author). Guideline synthesis last reviewed: July 2026.

All medication selection, timing, dose, and duration decisions remain clinician decisions and must account for bleeding risk, renal and hepatic function, drug interactions, and procedure-specific concerns.

Clinical Decision Framework

When to Prescribe Extended Prophylaxis After Surgery

Apply this framework after calculating the patient's PE risk using the Discharge or Triggered Reassessment tab:

Step 1 — Risk tier. If Low (<0.15%), extended prophylaxis is generally not indicated. If Moderate (0.15-0.34%), consider patient-specific factors. If High (≥0.35%) or Very High (≥1.0%), extended prophylaxis is strongly recommended unless contraindicated.

Step 2 — Bleeding assessment. Review absolute and relative contraindications above. If absolute contraindication present, use mechanical prophylaxis only and reassess daily.

Step 3 — Agent selection. First-line: enoxaparin 40 mg SC daily × 28 days (strongest evidence base). If LMWH contraindicated (HIT, refusal of injections): consider rivaroxaban 10 mg PO daily × 28-35 days. Avoid apixaban for extended prophylaxis (negative trial).

Step 4 — Patient education. Counsel on injection technique (if LMWH), signs/symptoms of DVT/PE, when to seek emergency care. Arrange 2-week follow-up or phone check-in.

Step 5 — Reassess at follow-up. If readmission or reoperation occurs, return to the Triggered Reassessment tab for recalculated risk and adjust prophylaxis accordingly.

Disclaimer: The following is reference information synthesized from published guidelines. It does not constitute a prescribing recommendation from this model. This extended prophylaxis reference is provided for clinical decision support and is NOT a substitute for individualized clinical judgment. All prescribing decisions must account for patient-specific bleeding risk, renal/hepatic function, drug interactions, and surgical team preferences.

Content synthesized from: ASH 2018/2019 VTE Guidelines | ACCP/CHEST 9th Ed | NICE NG89 | ASCRS 2023 | Tellor 2015 | Choi 2025

Locked Calculator Architecture

Discharge tab: bedside PE, DVT, and composite VTE risk at discharge using clinically available variables, work RVU spline terms, and pooled CPT-3 family. Validated AUCs: PE 0.811, DVT 0.814, VTE 0.811.

Triggered Reassessment tab: PE-only triggered reassessment using the same baseline/procedure backbone plus readmission timing and reoperation timing. Validated AUC: 0.892.

Data Source & Validation

  • Training: ACS-NSQIP PUF 2020-2023 complete-case cohort (3,864,605 cases)
  • Temporal validation: 2024 complete-case cohort (956,434 cases; 3,413 PE events)
  • Performance reporting: AUC, Brier score, log loss, calibration intercept, calibration slope, threshold operating characteristics, and bootstrap confidence intervals
  • Outputs: calculator coefficients, spline knots, CPT family mapping, and clinician guidance exported directly from the locked Stata pipeline

Peer-Reviewed Publication

Dallal RM, Riggio J, Li M, Eraso LH, Moran B, Merli GJ. 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. 2026 Jun 19. Epub ahead of print. PMID: 42319019 · doi:10.1097/XCS.0000000000002074

Calculator Simplification

This bedside calculator intentionally omits functional status to reduce data-entry burden. The locked manuscript models retained functional status, but its incremental discrimination gain was negligible in ablation testing. Calculator estimates therefore prioritize usability over exact reproduction of the full manuscript model.

Clinical Interpretation

These predictions estimate observed postoperative risk under real-world NSQIP-era care patterns, not untreated biologic thrombosis risk. Prophylaxis exposure is incompletely observed in NSQIP, so some patients who appear lower risk may reflect successful preventive care rather than intrinsically low thrombosis risk.

Use Constraints

Use only for operative patients similar to those represented in ACS-NSQIP. This tool does not estimate bleeding risk and should support, not replace, clinician judgment about thromboprophylaxis, mobility, malignancy, and post-discharge surveillance.

NOT FDA-CLEARED. Research and clinical decision support only.

Clinicians retain full responsibility for all treatment decisions. Does NOT model bleeding risk.

Reference: Dallal RM, Riggio J, Li M, Eraso LH, Moran B, Merli GJ. 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. 2026 Jun 19. Epub ahead of print. PMID: 42319019

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