Aortic And Peripheral Vascular Disease Scores

PREVENT III Risk Score Calculator – Chronic Limb-Threatening Ischemia (CLTI)

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PREVENT III Risk Assessment

Select each preoperative finding that applies to the patient. All five variables are required.

-- Total score
01

Dialysis-dependent renal failure

The patient requires ongoing dialysis for renal failure.

+4 points
02

Tissue loss

Ischemic ulceration or gangrene as the presenting CLTI feature, rather than ischemic rest pain alone.

+3 points
03

Age ≥75 years

Age at the time of preoperative assessment.

+2 points
04

Hematocrit ≤30%

Baseline preoperative hematocrit. The original report uses ≤30% in its abstract and narrative; Table 3 labels the threshold as <30%.

+2 points
05

Advanced coronary artery disease

History of myocardial infarction or prior coronary surgical or percutaneous revascularization.

+1 point
Please select an answer for all five variables to calculate the PREVENT III score.
-- PIII score
One-year prognostic risk group
Awaiting complete inputs
Complete all five variables to display the risk category and reported 1-year AFS.
Clinical interpretation This score is intended to support preoperative risk stratification in selected patients with CLTI being considered for infrainguinal bypass. It does not determine the revascularization strategy by itself.

The reported AFS values are cohort-level Kaplan–Meier estimates, not individualized probabilities. AFS is freedom from ipsilateral major amputation proximal to the ankle and all-cause mortality.

About the PREVENT III Risk Score

The PREVENT III (PIII) risk score is a prognostic model developed to stratify the risk of one-year amputation-free survival in patients with critical limb ischemia selected for infrainguinal vein bypass surgery.

The original model assigns weighted integer points to five preoperative predictors identified in a multivariable Cox proportional hazards model. The total score ranges from 0 to 12.

Scoring variables

PredictorDefinitionPoints
DialysisDialysis-dependent renal failure4
Tissue lossUlcer or gangrene3
Age≥75 years2
Hematocrit≤30%*2
Advanced CADPrior MI or coronary revascularization1

*The publication's abstract and narrative specify hematocrit ≤30%, while its model table labels the criterion as <30%. This implementation follows the abstract and narrative and makes the source discrepancy explicit.

Risk categories and reported one-year AFS

ScoreRisk groupDerivation cohort AFS
≤3Low85.9%
4–7Intermediate73.0%
≥8High44.6%

Validation findings

In the original study, estimated one-year AFS was 87.7%, 63.7%, and 45.0% in the low-, intermediate-, and high-risk groups in the PREVENT III internal validation cohort. In the multicenter external cohort, corresponding estimates were 86.3%, 70.1%, and 47.8%.

A subsequent external validation study used a four-variable adaptation that omitted hematocrit because of missing data, assigning 4 points for dialysis, 3 for tissue loss, 2 for age ≥75, and 1 for CAD. That modified implementation is not the five-variable original score calculated above.

Clinical Application

Intended population

  • Adults with chronic limb-threatening ischemia (historically termed critical limb ischemia).
  • Patients selected for infrainguinal bypass surgery.
  • The original PREVENT III cohort used autogenous vein bypass; applicability to other conduits and contemporary treatment pathways is less certain.

Important limitations

  • The model was developed using data from patients treated in the early 2000s.
  • It predicts a composite one-year outcome, not graft patency, wound healing, or limb salvage alone.
  • It is not validated as a general-purpose risk score for all patients with CLTI, endovascular treatment, or nonoperative management.
  • Risk categories describe group-level outcomes and should not be interpreted as precise individual predictions.
  • The original paper contains a minor threshold inconsistency for hematocrit (≤30% in the abstract/narrative versus <30% in the model table).

Contemporary guideline context

The 2024 ACC/AHA multisociety PAD guideline emphasizes multidisciplinary evaluation and individualized selection of surgical, endovascular, or hybrid revascularization based on anatomy, conduit availability, comorbidities, and patient preferences. The PREVENT III score should therefore be considered one prognostic input rather than a stand-alone treatment-selection rule.

References

Schanzer A, Mega J, Meadows J, Samson RH, Bandyk DF, Conte MS. Risk stratification in critical limb ischemia: derivation and validation of a model to predict amputation-free survival using multi-center surgical outcomes data. Journal of Vascular Surgery. 2008;48(6):1464–1471. DOI: 10.1016/j.jvs.2008.07.062.
Schanzer A, Goodney PP, Li Y, et al. Validation of the PIII CLI risk score for the prediction of amputation-free survival in patients undergoing infrainguinal autogenous vein bypass for critical limb ischemia. Journal of Vascular Surgery. 2009;50(4):769–775. DOI: 10.1016/j.jvs.2009.05.055.
Gornik HL, Aronow HD, Goodney PP, et al. 2024 ACC/AHA Multisociety Guideline for the Management of Lower Extremity Peripheral Artery Disease. Circulation. 2024. Official guideline: 10.1161/CIR.0000000000001251.
Clinical disclaimer: The PREVENT III score is a prognostic aid and must not be used as the sole basis for clinical decisions. Interpret the result alongside limb staging, anatomy, conduit availability, frailty, comorbidities, functional status, patient goals, and multidisciplinary vascular assessment. The score does not replace contemporary clinical judgement or guideline-directed care.
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