Appendix B: Risk Assessment Models, Protocols, and Order Sets

This appendix contains a number of VTE risk-assessment models (RAMs) and order set examples. These tools help reinforce the local definitions of best practice (protocols) in VTE prevention. It is important to review these models in the context of realistic case scenarios and to think ahead about how user friendly each model would be for the ordering provider and how adherence to the protocol could be audited and tracked. Be sure to review these models in conjunction with a review of Chapters 4 and 5 (Implementation and Clinical Decision Support), as well as the patient case scenarios at the end of this appendix).

Many of the VTE risk assessment models (RAMs) are depicted for completeness and to provide context of what NOT to use. VTE RAMs that have been used most widely and successfully are highlighted and commented on.

B1. Simple Prompt.
B2. Opt Out.

Qualitative/Grouping/Bucket Models

B3. Simple Medical Model (Dobrominski).
B4. NHS/NICE Model.*
B5. NHS/NICE Model—tick box variant.
B6. "Classic" 3 bucket model reflecting AT8 * (Also go to Chapter 4 and Chapter 5 implementation example).
B7. Updated 3 bucket model—more consistent with AT9 * (Also go to Chapter 4).
B8. Australia/New Zealand Working Party.
B9. Italian model (Scaglione).

Also go to UC Davis example in Chapter 4.

Point-Based Individualized Quantitative Models

B10. Caprini model * (Also go to Chapter 4, and University of Michigan CPOE implementation example in Chapter 5).
B11. Brigham and Women's Hospital (Kucher)—Used successfully in alerts.
B12. Padua model.
B13. Modified Padua.
B14. IMPROVE VTE Risk Model.
B15. Case Scenarios to Test Models and Example Order Sets.

Intermountain, Premier, and Rogers models are not in appendix but are discussed in Chapter 4.

* Shows promise with 7-factor model.

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B.1. Example of a "Prompt" for VTE Prevention Order

DVT PROPHYLAXIS ORDERS

Anti-Thromboembolism Stockings.
Sequential Compression Devices.
UFH 5,000 units SubQ q 12 hours.
UFH 5,000 units SubQ q 8 hours.
LMWH (enoxaparin) 40 mg SubQ q day.
LMWH (enoxaparin) 30 mg SubQ q 12 hours.
No Prophylaxis, Ambulate.

Key: UFH = unfractionated heparin; LMWH = low molecular weight heparin; SubQ = subcutaneous.

Strengths:

Easy to construct.

Limitations:

Provides no real clinical decision support.
This is a prompt to think about VTE prophylaxis but cannot really be considered a protocol.
All options look like equals; there is no link to risk assessment.
Use can lead to modest improvement over no prompt, but excellence is difficult to achieve.
Does not meet regulatory/Joint Commission measures 1 and 2 for prophylaxis.

Variations and other comments:

VTE and bleeding risk factors could be listed in same area, on reverse of paper orders, or available via links in computerized physician order entry orders.

References:

1. O'Connor C, Adhikari N, DeCaire K, et al. Medical admission order sets to improve deep vein thrombosis prophylaxis rates and other outcomes. J Hosp Med 2009;4(2):81-9.
2. Maynard G. Medical admission order sets to improve deep vein thrombosis prevention: a model for others or a prescription for mediocrity? J Hosp Med 2009;4(2):77-80.

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B.2. Opt-Out Approach

DVT PROPHYLAXIS ORDERS - Medical Inpatients

Pharmacologic prophylaxis

|_X_| LMWH (enoxaparin) 40 mg SubQ daily

|___| LMWH (enoxaparin) 30 mg SubQ daily (creatinine clearance <30 mL/min)
|___| UFH 5,000 units SubQ q 8 hours
|___| UFH 5,000 units SubQ q 12 hours

Mechanical prophylaxis (for patients at risk for VTE, with contraindications to anticoagulant)

|___| Sequential Compression Devices (SCDs), bilateral
|___| Plexipulses, bilateral

|___| No Prophylaxis, Ambulate: Patient is ambulatory and without major risk factors, low risk.
|___| No Prophylaxis, Ambulate: Patient is at risk for VTE but on therapeutic anticoagulation.
|___| No prophylaxis, Ambulate: Patient is at risk for VTE but has contraindications to SCDs and anticoagulation.

Key: UFH = unfractionated heparin; LMWH = low molecular weight heparin; SubQ = subcutaneous.

Strengths:

It is easy to construct.
It is intuitive.
Most users will accept the default (presented here as a prechecked selection for LMWH prophylaxis).
Default can be varied for different services (see variations).

Limitations:

It can result in over-prophylaxis, particularly if used for medical inpatients since a substantial percentage of medical inpatients are at relatively low risk for VTE.
Use in medical patients is explicitly discouraged by ACP and AT9 guidelines.
It does not reliably capture VTE risk level and statement of low risk is not defined.

Variations and other comments:

May be very appropriate for some services with relatively uniform VTE risk level.
Example 1: colorectal cancer surgery orders - default might be enoxaparin PLUS sequential compression devices.
Example 2: orthopedic surgery default might be rivaroxaban or other anticoagulant (to start morning of postop day 1) and sequential compression devices.
Example 3: Craniotomy patient default might be sequential compression devices until designated time postop, at which time anticoagulant prophylaxis would be added.
Variation: Add in start time for anticoagulant prophylaxis post op.
Variation: Could add in special instructions about extended prophylaxis.
VTE and bleeding risk factors could be listed in same area, on reverse of paper orders, or available via links in computerized physician order entry orders.

References:

1. Kahn SR, Lim W, Dunn AS, et al. Prevention of VTE in nonsurgical patients. Chest 2012; 141:2 suppl e195S-e226S; doi:10.1378/chest.11-2296.
2. Qaseem A, Chou R, Humphrey LL, et al. Venous thromboembolism prophylaxis in hospitalized patients: a clinical practice guideline from the American College of Physicians. Ann Intern Med 2011;Nov 1;155(9):625-32.
3. Crowther MA. Medical prophylaxis: the value of an "opt in" policy. J Thromb Thrombolysis 2013;35:368-70.

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B.3 Medical Population—A Simple Qualitative Model. Patients Considered At Risk Unless ≤40 Or Normal Mobility

The model is available at . It appears in Figure 1. Initial VTE risk assessment. The full article in which the model appears is Dobromirski M, Cohen AT. How I manage venous thromboembolism in hospitalized medical patients. Blood 2012; 120(8):1562-69. . Accessed May 5, 2016.

Strengths:

Easy to construct and follow, resulting in higher rates of “correct” DVT prophylaxis.
Low-risk group clearly defined (medical patient ≤40, or >40 and normal mobility).
Balances default to prophylaxis with explicit efforts to minimize anticoagulant prophylaxis for those at highest bleeding risk.

Limitations:

Can result in over-prophylaxis (all over 40 with limited mobility considered for anticoagulant prophylaxis, regardless of expected length of stay, chronicity of limited mobility, or absence of acute illness).

Variations and other comments:

Variation: Add in more groups that would be considered low risk.

References:

1. Dobromirski M, Cohen AT. How I manage venous thromboembolism in hospitalized medical patients. Blood 2012;120(8):1562-9. . Accessed May 5, 2016.
2. Kahn SR, Lim W, Dunn AS, et al. Prevention of VTE in nonsurgical patients. Antithrombotic therapy and prevention of thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest 2012;141:2 suppl e195S-e226S; doi:10.1378/chest.11-2296.
3. Qaseem A, Chou R, Humphrey LL, et al. Venous thromboembolism prophylaxis in hospitalized patients: a clinical practice guideline from the American College of Physicians. Ann Intern Med 2011;Nov 1;155(9):625-32.
4. Khanna R, Vittinghoff E, Maselli J, et al. Unintended consequences of a standard admission order set on venous thromboembolism prophylaxis and patient outcomes. J Gen Intern Med 2012;27(3):318-24.
5. Bagot C, Gohil S, Perrott R, et al. The use of an exclusion-based risk assessment model for venous thrombosis improves uptake of appropriate thromboprophylaxis in hospitalized medical patients. QJM 2010;103(8):597-605.

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B.4. NHS - NICE Guideline Approach to VTE and Bleeding Risk Assessment in Medical and Surgical Patients. A Qualitative Model With Simple Exclusions for Populations That Don't Need Prophylaxis

Patients who are at risk of VTE
Medical patients If mobility significantly reduced mobility for ≥3 days or If expected to have ongoing reduced mobility relative to normal state plus any VTE the risk factor.	Surgical patients and patients with trauma If total anaesthetic + surgical time >90 minutes or If surgery involves pelvis or lower limb and total anaesthetic + surgical time >60 minutes or If acute surgical admission with inflammatory or intra-abdominal condition or If expected to have significant reduction in mobility or If any VTE risk factor present
VTE risk factors¹ Active cancer or cancer treatment. Age >60 years. Critical care admission. Dehydration. Known thrombophilias. Obesity (body mass index >30 kg/m²). One or more significant medical comorbidities (for example: heart disease; metabolic, endocrine, or respiratory pathologies; acute infectious diseases; inflammatory conditions). Personal history or first-degree relative with a history of VTE. Use of hormone replacement therapy. Use of oestrogen-containing contraceptive therapy. Varicose veins with phlebitis.

Patients who are at risk of VTE

Medical patients

If mobility significantly reduced mobility for ≥3 days or
If expected to have ongoing reduced mobility relative to normal state plus any VTE the risk factor.

Surgical patients and patients with trauma

If total anaesthetic + surgical time >90 minutes or
If surgery involves pelvis or lower limb and total anaesthetic + surgical time >60 minutes or
If acute surgical admission with inflammatory or intra-abdominal condition or
If expected to have significant reduction in mobility or
If any VTE risk factor present

VTE risk factors¹

Active cancer or cancer treatment.
Age >60 years.
Critical care admission.
Dehydration.
Known thrombophilias.
Obesity (body mass index >30 kg/m²).
One or more significant medical comorbidities (for example: heart disease; metabolic, endocrine, or respiratory pathologies; acute infectious diseases; inflammatory conditions).
Personal history or first-degree relative with a history of VTE.
Use of hormone replacement therapy.
Use of oestrogen-containing contraceptive therapy.
Varicose veins with phlebitis.

Patients who are at risk of bleeding

Active bleeding.
Acquired bleeding disorders (such as acute liver failure).
Concurrent use of anticoagulants known to increase the risk of bleeding (such as warfarin with international normalised ratio [INR] >2).
Lumbar puncture/epidural/spinal anaesthesia within the previous 4 hours or expected within the next 12 hours.
Acute stroke.
Thrombocytopenia (platelets <75 × 10⁹/l).
Uncontrolled systolic hypertension (≥230/120 mmHg).
Untreated inherited bleeding disorders (such as haemophilia and von Willebrand's disease).

Strengths:

Relatively intuitive and easy to use.
Well-defined low-risk state for medical patients: normal-state mobility or reduced mobility but no other VTE risk factor.
Can be used for both general medicine and surgery patients.

Limitations:

Operational definition of mobility calls for prediction of future mobility state, which can result in problems with auditing and variation in order set use.
It may encourage overly aggressive prophylaxis (e.g., 61-year-old man fully mobile undergoing any surgery would be a candidate for prophylaxis).
Medical patients who can ambulate or maintain their normal level of mobility would not get prophylaxis even if myriad VTE risk factors were present.
See Cases 2 and 3 in Appendix B.15 for scenarios around potentially ambiguous interpretations. Would a person who can ambulate, but with myocardial infarction, congestive heart failure, and recent sepsis receive prophylaxis? What about a woman with multiple VTE risk factors who may or may not be able to ambulate with a walker after surgery?
Some surgical populations benefit from combination (anticoagulant PLUS mechanical) prophylaxis. While the model depicted does not address this possibility, the NICE guideline and encouraged practice is that all surgical patients without anticoagulant contraindications warrant combination prophylaxis. This approach may lead to overprescribing of combination prophylaxis.

Variations and other comments:

Prophylactic choices would be explicitly listed in order sets. For example, patients at risk would be offered low molecular weight heparin or unfractionated heparin, unless at risk of bleeding, when intermittent pneumatic compression could be offered.
Variation: Separate order sets for medical and surgical patients.

References:

Also see: Basey AJ, Krska J, Kennedy TD, et al. Challenges in implementing government-directed VTE guidance for medical patients: a mixed methods study. BMJ Open 2012;2(6). . Accessed May 5, 2016.

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B.5. NHS - NICE Guideline Approach to VTE and Bleeding Risk Assessment in Medical and Surgical Patients. (Variant of the NHS Qualitative Model Using "Tick" Boxes)

The NICE Tick model is available at (PDF, 182 KB).

Strengths:

It is relatively intuitive and easy to use.
It can be used for both general medicine and surgery patients.
Case studies in environments with mandated use have reported improved risk assessment rates, increased use of anticoagulant prophylaxis, and reductions in HA-VTE.
It simplifies mobility criteria.
Opportunities arise to stop risk assessment as soon as patient qualifies for prophylaxis, perhaps making it easier to fill out.

Limitations:

Operational definition of mobility calls for prediction of future mobility state, which can result in problems with auditing and variation in order set use.
It may encourage overly aggressive prophylaxis in some (e.g., 61-year-old man fully mobile undergoing any surgery would be a candidate for prophylaxis).
Medical patients who can ambulate or maintain their normal level of mobility would not get prophylaxis even if myriad VTE risk factors were present.
Some surgical populations benefit from combination (anticoagulant PLUS mechanical) prophylaxis. While the model depicted here does not explicitly demonstrate this, the NICE guideline is that all surgical patients without anticoagulant contraindications warrant combination prophylaxis. This approach may lead to overprescribing of combination prophylaxis.

Variations and other comments:

Prophylactic choices would be explicitly listed in order sets. For example, patients at risk would be offered low molecular weight heparin or unfractionated heparin, unless at risk of bleeding, when intermittent pneumatic compression could be offered.
Variation: Separate order sets for medical and surgical patients.

References:

1. Reducing the risk of venous thromboembolism (deep vein thrombosis and pulmonary embolism) in patients admitted to hospital. NICE Clinical guideline 92. London, UK: National Institute for Health and Clinical Excellence; 2010. . Accessed May 5, 2016.
2. Roberts LN, Porter G, Barker RD, et al. Comprehensive venous thromboembolism prevention programme incorporating mandatory risk assessment reduces the incidence of hospital-associated thrombosis. Chest 2013; 144(4):1276-81. . Accessed May 5, 2016.

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B.6. "Classic" 3 Bucket Model

Also go to Chapter 4 (for discussion) and Chapter 5 for an example of computerized physician order entry (CPOE) implementation.

Venous Thromboembolism Risk Assessment & Prophylaxis PHYSICIAN ORDER Sheet

Complete Assessment at ADMISSION, POST-OP, AND TRANSFER

DVT/PE RISK LEVEL & PROPHYLAXIS ORDERS
□ Low Risk Observation patients; expected LOS <48 hrs: Minor/ Ambulatory surgery unless multiple strong risk factors Ambulatory patient with no acute hospital-related VTE risk factors	\|___\| Early ambulation, education \|___\| Education
□ Moderate Risk Most medical/surgical patients Impaired ambulation, CHF, pneumonia, active inflammation, dehydration, varicose veins, age >65 and acute illness, many other factors. All patients not in Low or High Risk categories (see reverse for more risk factors)	CHOOSE ONE pharmacologic option \|___\| Enoxaparin 40 mg SC q 24 hrs \|___\| Enoxaparin 30 mg SC q 24 hrs (renal insufficiency dosing) \|___\| Heparin 5,000 units SC q 8 hrs \|___\| Heparin 5,000 units SC every 12 hrs (weight <50kg or age >75)
□ High Risk Elective hip or knee arthroplasty Acute spinal cord injury with paresis Multiple major trauma Abdominal or pelvic surgery for cancer Craniotomy or spine surgery for cancer after bleeding risk subsides	CHOOSE ONE pharmacologic option \|___\| Enoxaparin 40 mg SC q day \|___\| Enoxaparin 30 mg SC q 24 hrs (for renal insufficiency) \|___\| Heparin 5,000 units SC q 8 hrs (end stage renal disease only) \|___\| Enoxaparin 30 mg SC q 12 hrs (knee replacement) \|___\| Fondaparinux 2.5 mg SC q day
AND Sequential compression device
OR Contraindication to pharmacologic prophylaxis, including already on therapeutic anticoagulation (see reverse): ___________________________________ \|___\| Mechanical prophylaxis with sequential compression device OR \|___\| Contraindicated (peripheral vascular disease or wounds)

DVT/PE RISK LEVEL & PROPHYLAXIS ORDERS

□ Low Risk

Observation patients; expected LOS <48 hrs: Minor/ Ambulatory surgery unless multiple strong risk factors
Ambulatory patient with no acute hospital-related VTE risk factors

|___| Early ambulation, education
|___| Education

□ Moderate Risk

Most medical/surgical patients

Impaired ambulation, CHF, pneumonia, active inflammation, dehydration, varicose veins, age >65 and acute illness, many other factors.
All patients not in Low or High Risk categories (see reverse for more risk factors)

CHOOSE ONE pharmacologic option

|___| Enoxaparin 40 mg SC q 24 hrs

|___| Enoxaparin 30 mg SC q 24 hrs (renal insufficiency dosing)

|___| Heparin 5,000 units SC q 8 hrs

|___| Heparin 5,000 units SC every 12 hrs (weight <50kg or age >75)

□ High Risk

Elective hip or knee arthroplasty
Acute spinal cord injury with paresis
Multiple major trauma
Abdominal or pelvic surgery for cancer
Craniotomy or spine surgery for cancer after bleeding risk subsides

CHOOSE ONE pharmacologic option

|___| Enoxaparin 40 mg SC q day
|___| Enoxaparin 30 mg SC q 24 hrs (for renal insufficiency)
|___| Heparin 5,000 units SC q 8 hrs (end stage renal disease only)
|___| Enoxaparin 30 mg SC q 12 hrs (knee replacement)
|___| Fondaparinux 2.5 mg SC q day

AND

Sequential compression device

Contraindication to pharmacologic prophylaxis, including already on therapeutic anticoagulation (see reverse): ___________________________________

|___| Mechanical prophylaxis with sequential compression device OR
|___| Contraindicated (peripheral vascular disease or wounds)

________________________________________________________________________
SIGNATURE / PROVIDER ID DATE / TIME

Strengths:

Relatively intuitive and easy to use.
Fairly simple to monitor and audit.
Can be used for medical, surgical, and orthopedic patients.
Good inter-observer agreement.
Captures VTE risk, and the risk level is directly linked to appropriate choices for prophylaxis.
Used in multiple sites that have reduced HA-VTE without any detection of increased bleeding.

Limitations:

It may encourage overly aggressive prophylaxis in some relatively low-risk patients.
Operational definition of “expected LOS <48 hours” calls for judgment and could lead to ambiguity (e.g., while 40 percent of medical inpatients may be out of the hospital within 48 hours, it is not always possible to predict).
It is not as granular as a point-based model with full listing of every risk factor.
Anticoagulant prophylaxis posed as preferred prophylaxis in cases at risk for VTE and no anticoagulant contraindication, while AT9 guidelines may prefer mechanical prophylaxis in select groups of surgical patients.

Variations and other comments:

Many variations are possible, including those that follow here.
Unfractionated heparin dose of 5,000 q 8 hours or q 12 hours acceptable even for patients who are younger, higher weight.
Variation: More options (such as rivaroxaban or warfarin) could be listed for major orthopedic surgery patients.
Variation: Many hospitals include critically ill patients in ICU settings in highest risk groups (note that the benefit of this practice has little direct evidence and is extrapolated from high-risk surgical patients).
Variation: Separate order set for orthopedics, surgery, and medical patients.
Variation: “Two bucket” model if used just for medical inpatients.
Desirable to carve out several special populations from this model (for example, obstetric patients, uncomplicated cardiovascular surgery patients, neurosurgery patients).

References:

1. Maynard G, Stein J. Designing and implementing effective VTE prevention protocols: lessons from collaborative efforts. J Thromb Thrombolysis 2010 Feb:29(2):159-66. . Accessed May 5, 2016.
2. Maynard G, Morris T, Jenkins I, et al. Optimizing prevention of hospital acquired venous thromboembolism: prospective validation of a VTE risk assessment model. J Hosp Med 2010 Jan:5(1):10-18.

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B. 7. The 3 Bucket Model—Broader Definition of Low Risk Than the Classic Model

Venous Thromboembolism Risk Assessment & Prophylaxis PHYSICIAN ORDER Sheet

Complete Assessment at ADMISSION, POSTOP, AND TRANSFER

DVT/PE RISK LEVEL & PROPHYLAXIS ORDERS
□ Low Risk Observation patients; expected LOS <48 hrs: Minor/ ambulatory surgery unless multiple strong risk factors. Patients no longer/never ill, awaiting disposition. Ambulatory cancer patients admitted for short chemotherapy infusion. Medical patient able to ambulate outside room and not meeting criteria for Moderate or High risk.	\|___\| Early ambulation, education \|___\| Education
□ Moderate Risk Most medical/surgical patients Moderate to Major surgery with impaired mobility. Moderate to Major surgery with any VTE risk factor. Active cancer/cancer therapy with expected LOS >48 hours. Medical patient, decrease in usual ambulation AND VTE risk factors: MI, stroke, CHF, pneumonia, active inflammation, dehydration, known thrombophilia or prior VTE, age >65, many other factors (see reverse/link for more risk factors).	CHOOSE ONE pharmacologic option \|___\| Enoxaparin 40 mg SC q 24 hrs \|___\| Enoxaparin 30 mg SC q 24 hrs (renal insufficiency) \|___\| Heparin 5,000 units SC q 8 hrs \|___\| Heparin 5,000 units SC every 12hrs (<50kg or age>75)
□ High Risk Elective hip or knee arthroplasty Acute spinal cord injury with paresis Multiple major trauma Abdominal or pelvic surgery for cancer Craniotomy or spine surgery for cancer after bleeding risk subsides	CHOOSE ONE pharmacologic option \|___\| Enoxaparin 40 mg SC q day \|___\| Enoxaparin 30 mg SC q 24 hrs (for renal insufficiency) \|___\| Heparin 5,000 units SC q 8 hrs (ESRD only) \|___\| Enoxaparin 30 mg SC q 12 hrs (knee replacement) \|___\| Fondaparinux 2.5 mg SC q day
AND Sequential compression device
OR Contraindication to pharmacologic prophylaxis, including already on therapeutic anticoagulation (see reverse): ____________________________________ Mechanical prophylaxis with sequential compression device OR Contraindicated (peripheral vascular disease or wounds)

DVT/PE RISK LEVEL & PROPHYLAXIS ORDERS

□ Low Risk

Observation patients; expected LOS <48 hrs:
Minor/ ambulatory surgery unless multiple strong risk factors.
Patients no longer/never ill, awaiting disposition.
Ambulatory cancer patients admitted for short chemotherapy infusion.
Medical patient able to ambulate outside room and not meeting criteria for Moderate or High risk.

|___| Early ambulation, education
|___| Education

□ Moderate Risk

Most medical/surgical patients

Moderate to Major surgery with impaired mobility.
Moderate to Major surgery with any VTE risk factor.
Active cancer/cancer therapy with expected LOS >48 hours.
Medical patient, decrease in usual ambulation AND VTE risk factors: MI, stroke, CHF, pneumonia, active inflammation, dehydration, known thrombophilia or prior VTE, age >65, many other factors (see reverse/link for more risk factors).

CHOOSE ONE pharmacologic option

|___| Enoxaparin 40 mg SC q 24 hrs
|___| Enoxaparin 30 mg SC q 24 hrs (renal insufficiency)
|___| Heparin 5,000 units SC q 8 hrs
|___| Heparin 5,000 units SC every 12hrs (<50kg or age>75)

□ High Risk

Elective hip or knee arthroplasty
Acute spinal cord injury with paresis
Multiple major trauma
Abdominal or pelvic surgery for cancer
Craniotomy or spine surgery for cancer after bleeding risk subsides

CHOOSE ONE pharmacologic option

|___| Enoxaparin 40 mg SC q day
|___| Enoxaparin 30 mg SC q 24 hrs (for renal insufficiency)
|___| Heparin 5,000 units SC q 8 hrs (ESRD only)
|___| Enoxaparin 30 mg SC q 12 hrs (knee replacement)
|___| Fondaparinux 2.5 mg SC q day

AND

Sequential compression device

Contraindication to pharmacologic prophylaxis, including already on therapeutic anticoagulation (see reverse): ____________________________________

Mechanical prophylaxis with sequential compression device OR
Contraindicated (peripheral vascular disease or wounds)

________________________________________________________________________
SIGNATURE / PROVIDER ID DATE / TIME

Strengths:

Retains relative ease of use, although more complicated than classic 3 bucket model.
Fairly simple to monitor and audit.
Provides that patients default to low risk if they do not meet criteria for moderate or high risk, with less prophylaxis of those with little chance of developing HA-VTE than the classic model.
Can be used for medical, surgical, and orthopedic patients.
Captures VTE risk, and risk level is directly linked to appropriate choices for prophylaxis.

Limitations:

It has demonstrated efficacy but is limited to unpublished experience thus far.
Operational definition of "expected LOS <48 hours" calls for judgment and could lead to ambiguity. Surgery types "minor, moderate, major" need operational definitions, similar to the NICE model.
Anticoagulant prophylaxis is preferred prophylaxis in cases at risk for VTE and no anticoagulant contraindication, while AT9 guidelines may prefer mechanical prophylaxis in select groups.

Variations and other comments:

Many variations are possible.
Unfractionated heparin dose of 5,000 q 8 hours or q 12 hours is acceptable even in patients who are younger, higher weight.
Variation: More options (such as rivaroxaban or warfarin) could be listed for major orthopedic surgery patients.
Variation: Many hospitals include critically ill patients in ICU settings to highest risk groups (note that the benefit of this practice has little direct evidence and is extrapolated from high-risk surgical patients).
Variation: Separate order set for orthopedics, surgery, and medical patients, which may be desirable in many institutions. “Two bucket” model could be used if just for medical inpatients.
It is desirable to carve out several special populations from this model (for example, obstetric patients, uncomplicated cardiovascular surgery patients, neurosurgery patients who may have mechanical prophylaxis as a viable or preferred option).

References:

1. Maynard G, Stein J. Designing and implementing effective VTE prevention protocols: lessons from collaborative efforts. J Thromb Thrombolysis 2010 Feb;29(2):159-66. . Accessed May 5, 2016.

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B.8. VTE Risk Assessment Model Derived From the Australian and New Zealand Working Party on Management of Venous Thromboembolism

Risk Category	Medical Risk Factors	Surgical Risk Factors	Prophylaxis
High	Ischemic stroke. Congestive heart failure (decompensated). Shock. Personal history—VTE. Thrombophilia. Active cancer. Acute or chronic lung disease/COPD. Acute or chronic inflammatory disease. Age >60 years, unless otherwise ambulant and no other risk factors.	Orthopedic surgery of pelvis, hip, or total knee replacement. Major surgery*, age >60 years. Major surgery, age >40 years with medical risk factors. Multiple trauma.	Surgical patients LMWH or UFH. AND Mechanical prophylaxis. Medical Patients LMWH or UFH. (Mechanical prophylaxis if contraindication to chemoprophylaxis).
Moderate	Major surgery*, age 40-60 years without medical risk factors Minor surgery, age >60 years without medical risk factors	UFH. OR Mechanical prophylaxis.
Low	Minor medical illness. Absence of medical risk factors listed above.	Major surgery, age 16-40 years with no other risk factors. Minor surgery, age 16-60 years with no other risk factors.	Surgical Consider mechanical prophylaxis. Medical No prophylaxis.

Risk Category

Medical Risk Factors

Surgical Risk Factors

Prophylaxis

High

Ischemic stroke.
Congestive heart failure (decompensated).
Shock.
Personal history—VTE.
Thrombophilia.
Active cancer.
Acute or chronic lung disease/COPD.
Acute or chronic inflammatory disease.
Age >60 years, unless otherwise ambulant and no other risk factors.

Orthopedic surgery of pelvis, hip, or total knee replacement.
Major surgery*, age >60 years.
Major surgery, age >40 years with medical risk factors.
Multiple trauma.

Surgical patients

LMWH or UFH.

AND

Mechanical prophylaxis.

Medical Patients

LMWH or UFH.
(Mechanical prophylaxis if contraindication to chemoprophylaxis).

Moderate

Major surgery*, age 40-60 years without medical risk factors
Minor surgery, age >60 years without medical risk factors

UFH.

Mechanical prophylaxis.

Low

Minor medical illness.
Absence of medical risk factors listed above.

Major surgery, age 16-40 years with no other risk factors.
Minor surgery, age 16-60 years with no other risk factors.

Surgical

Consider mechanical prophylaxis.

Medical

No prophylaxis.

*Major surgery = any intra-abdominal surgery and all other surgery lasting >45 minutes.
COPD = chronic obstructive pulmonary disease; VTE = venous thromboembolism; LMWH = low molecular weight heparin; UFH = low dose unfractionated heparin

Strengths:

Demonstrated in Australian literature to increase prophylaxis.
Endorsed by a national guideline.
Reduced HA-VTE in one report (reduction did not reach statistical significance in another).
Achieved improvement in paper environment without advanced clinical decision support.
Can be used in both medical and surgical populations.
Relatively intuitive and easy to use.

Limitations:

May induce over-prophylaxis in relation to current AT9 and ACP guidelines.
Uneven results in reports.

Variations and other comments:

Present orthopedics, surgery, and medical risk assessment models separately.

References:

1. Australian and New Zealand Working Party on the Management and Prevention of Venous Thromboembolism . Prevention of venous thromboembolism: best practice guidelines for Australia and New Zealand. 4th ed. Baulkham Hills, New South Wales, Australia: Health Education and Management Innovations; 2007.
2. Gallagher M, Oliver K, Hurwitz M. Improving the use of venous thromboembolism prophylaxis in an Australian teaching hospital. Qual Saf Health Care 2009;18:408-12.
3. Liu DS, Lee MM, Spelman T, et al. Medication chart intervention improves inpatient thromboembolism prophylaxis. Chest 2012;141:632-41.

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B.9. Italian Qualitative Model Described by Scaglione

Risk Category	Medical Risk Factors	Surgical Risk Factors	Prophylaxis
High	Acute diseases with/without VTE risk factors. VTE risk factors: Obesity. Varicose veins. Bedridden. Pregnancy and puerperium. Estrogens. Inflammatory bowel disorders. Nephrotic syndrome. Active cancer. Myeloproliferative disorder. Previous VTE. Paralysis. Hypercoagulability or known thrombophilia.	Orthopedic surgery of pelvis, hip, or total knee replacement. Major surgery*, age >60 years. Major surgery, age >40 years with medical risk factors. Neurosurgery. Multiple Trauma.	Surgical Patients LMWH or UFH. With or without mechanical prophylaxis Orthopedic Surgery and Trauma LMWH. With or without mechanical prophylaxis Medical Patients LMWH or UFH. (Mechanical prophylaxis if contraindication to chemoprophylaxis).
Moderate	Major surgery*, age <60 years old without medical risk factors. Minor surgery, age >40 years old or with medical risk factors. Minor trauma treated with cast/splint with VTE risk factors. Arthroscopic knee surgery and elective spinal surgery with VTE risk factors.	Surgical or Ortho Patients LMWH or UFH. OR Mechanical prophylaxis. Trauma Patients LMWH or UFH.
Low	Absence of VTE risk factors and/or acute disease.	Major surgery, age 16-40 years with no other risk factors. Minor surgery, age <40 years, with no other risk factors.	Surgical Early ambulation. Medical No prophylaxis. Early ambulation.

Risk Category

Medical Risk Factors

Surgical Risk Factors

Prophylaxis

High

Acute diseases with/without VTE risk factors.
VTE risk factors:
- Obesity.
- Varicose veins.
- Bedridden.
- Pregnancy and puerperium.
- Estrogens.
- Inflammatory bowel disorders.
- Nephrotic syndrome.
- Active cancer.
- Myeloproliferative disorder.
- Previous VTE.
- Paralysis.
- Hypercoagulability or known thrombophilia.

Orthopedic surgery of pelvis, hip, or total knee replacement.
Major surgery*, age >60 years.
Major surgery, age >40 years with medical risk factors.
Neurosurgery.
Multiple Trauma.

Surgical Patients

LMWH or UFH.

With or without mechanical prophylaxis

Orthopedic Surgery and Trauma

LMWH.

With or without mechanical prophylaxis

Medical Patients

LMWH or UFH.
(Mechanical prophylaxis if contraindication to chemoprophylaxis).

Moderate

Major surgery*, age <60 years old without medical risk factors.
Minor surgery, age >40 years old or with medical risk factors.
Minor trauma treated with cast/splint with VTE risk factors.
Arthroscopic knee surgery and elective spinal surgery with VTE risk factors.

Surgical or Ortho Patients

LMWH or UFH.

Mechanical prophylaxis.

Trauma Patients

LMWH or UFH.

Low

Absence of VTE risk factors and/or acute disease.

Major surgery, age 16-40 years with no other risk factors.
Minor surgery, age <40 years, with no other risk factors.

Surgical

Early ambulation.

Medical

No prophylaxis.
Early ambulation.

Strengths:

Demonstrated to increase prophylaxis in Italian study and associated with reductions in HA-VTE.
Achieved improvement in paper environment without advanced clinical decision support.
Can be used in both medical and surgical populations.
Relatively intuitive and easy to use.

Limitations:

Likely to induce over-prophylaxis in relation to current AT9 and ACP guidelines.

Variations and other comments:

Present orthopedics, surgery, and medical risk assessment models separately.

References:

1. Scaglione L, Piobbici M, Pagano E, et al. Implementing guidelines for venous thromboembolism prophylaxis in a large Italian teaching hospital: lights and shadows. Haematologica 2005;90:678-84.

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Preventing Hospital-Associated Venous Thromboembolism