Interactive tool
Calculate the Villalta score
Assess the index leg, i.e. the one that had the deep vein thrombosis. The diagnosis of post-thrombotic syndrome requires a score of ≥ 5 or the presence of a venous ulcer.
How to use it
Instructions
When to apply it
- Not before 3–6 months after the acute deep vein thrombosis: in the acute and subacute phase symptoms reflect the event itself, not post-thrombotic syndrome, and the score loses meaning.
- The conventional time point in research protocols is 6 months, with confirmation at 12 months.
- For the diagnosis it is advisable that the score is ≥ 5 at two consecutive assessments at least 3 months apart: a single assessment can be affected by transient factors (immobility, heat, prolonged standing).
- Do not apply it during an ongoing recurrent thrombosis.
The eleven items
Symptoms (reported by the patient): pain, cramps, heaviness, paraesthesia, pruritus.
Signs (assessed by the clinician): pretibial oedema, skin induration, hyperpigmentation, redness, venous ectasia, pain on calf compression.
Each item is graded 0 = none, 1 = mild, 2 = moderate, 3 = severe. Grading is clinical and subjective: reproducibility improves considerably if the same clinician follows the patient over time.
An active venous ulcer on the index leg automatically classifies post-thrombotic syndrome as severe, whatever the sum of the other items. It is an overriding rule, not an additional score.
The main limitation
The score does not distinguish post-thrombotic signs from those of pre-existing primary chronic venous disease. In patients who already had varicose veins, oedema or pigmentation before the thrombosis, the score overestimates the post-thrombotic component. It is therefore useful to know the clinical picture before the thrombosis and to use the contralateral leg as an internal reference: a difference between the two legs is far more informative than the absolute value.
Clinical references
Guidelines and interpretation
| Score | Classification | Meaning |
|---|---|---|
| 0 – 4 | No post-thrombotic syndrome | Symptoms and signs absent or minimal |
| 5 – 9 | Mild | Diagnosis of post-thrombotic syndrome made |
| 10 – 14 | Moderate | Significant impact on quality of life |
| ≥ 15 | Severe | Disabling picture |
| Active venous ulcer | Severe | Regardless of the score |
Epidemiology and risk factors
Post-thrombotic syndrome affects 20–50% of patients after proximal deep vein thrombosis, with a severe form in 5–10%. The factors associated with a higher likelihood are: iliofemoral thrombosis (more than double the risk of distal DVT), recurrent ipsilateral thrombosis, obesity, persistent residual symptoms at 1 month, residual venous obstruction on duplex ultrasound and, above all, subtherapeutic anticoagulation in the first 3 months.
Prevention
- Adequate anticoagulation in the first months: the only intervention with a solid, proven preventive effect. Time in therapeutic range during the first 3 months correlates inversely with the incidence of post-thrombotic syndrome.
- Compression stockings: the randomised SOX trial (Kahn SR. et al., Lancet 2014) showed no preventive benefit of 30–40 mmHg stockings over placebo. Guidelines no longer recommend them for prevention alone, but they remain indicated for symptom control in symptomatic patients.
- Catheter-directed thrombolysis: the CaVenT and ATTRACT trials gave discordant results. ATTRACT did not reduce the overall incidence of post-thrombotic syndrome, but it reduced moderate-to-severe forms (a secondary outcome, more evident in the iliofemoral subgroup), at the cost of more major bleeding. The indication remains selective: young patient, extensive and recent iliofemoral thrombosis, severe symptoms, low bleeding risk.
- Early ambulation: does not increase the risk of embolism and reduces pain and swelling in the acute phase.
Treatment of established syndrome
- Made-to-measure graduated compression, the first-line measure in all symptomatic forms.
- Exercise and programmes to strengthen the calf muscle pump.
- Venoactive drugs as symptomatic support.
- In severe forms with documented iliocaval obstruction, consider recanalisation with venous stenting: it is the only intervention that acts on the haemodynamic cause and can achieve meaningful results on pain and ulcer healing.
- Where superficial reflux is also present, treating it may reduce the score, but this must be considered carefully if the superficial system acts as a collateral pathway around a deep obstruction.
Villalta is specific to post-thrombotic syndrome and is designed for longitudinal use in the individual patient. The VCSS measures the severity of chronic venous disease of any origin and is more sensitive to change after treatment. CEAP describes and classifies but does not grade severity. In the report and at follow-up the three tools are complementary, not alternatives.
References
Sources
- Villalta S. et al., Haemostasis 1994 — Assessment of validity and reproducibility of a clinical scale for the post-thrombotic syndrome (abstract).
- Kahn SR. et al., J Thromb Haemost 2009 (ISTH) — Definition of post-thrombotic syndrome of the leg for use in clinical investigations: a recommendation for standardization.
- Kahn SR. et al., Lancet 2014 — Compression stockings to prevent post-thrombotic syndrome: the SOX randomised placebo-controlled trial.
- Vedantham S. et al., N Engl J Med 2017 — Pharmacomechanical catheter-directed thrombolysis for deep-vein thrombosis (ATTRACT trial).
- Comerota AJ. et al., Circulation 2019 — Endovascular thrombus removal for acute iliofemoral deep vein thrombosis: analysis from the ATTRACT trial.
Quick-reference tool for healthcare professionals. It does not replace the original guidelines, the summaries of product characteristics or the specialist's clinical judgement. All calculations run in the browser: no patient data is transmitted to or stored on any server.