Superficial vein thrombosis (SVT) is a common disease that most often affects the veins of the lower limbs, but that can also be found in other sites (1,2)
- great saphenous vein is involved in 60-80% of cases, and the small saphenous vein in 10-20% (3)
- estimated that there is a prevalence of 3-11% in the general population 2, which is approximately two-fold higher than that of deep vein thrombosis (DVT) and pulmonary embolism (PE) combined
- SVT shares the prothrombotic risk factors with DVT and PE, including:
- a personal or family history of venous thromboembolism,
- active malignancy,
- recent surgery or trauma,
- immobilization, inherited thrombophilia,
- use of oral contraceptives,
- infectious diseases,
- obesity,
- and cardiac or respiratory failure
- SVT is often accompanied by the presence of varicose veins, which are documented in up to 80% of SVT patients (3)
- SVT has long been considered to be a benign entity, with more local than systemic implications
- however it has become clearer that SVT may be a manifestation of a systemic tendency to thrombosis, with a non-negligible risk of recurrence or concomitant DVT or PE at the time of SVT diagnosis
Risk of deep vein thrombosis or pulmonary embolism if superficial thrombophlebitis (1,2):
- prevalence of associated acute DVT in patients presenting with SVT is estimated to 6.8%-40%
- reason for the range of associated acute DVT is because of the wide variation in study design, patient characteristics, symptomatic status, type of SVT, inpatient versus outpatient setting, indications, and whether or not any noninvasive testing was performed.
- a study based on outpatients diagnosed with SVT (2)
- the incidence of acute DVT was 13%
- however, the incidence varied from 6.3% in patients with varicose veins, 33% in patients without varicose veins, and 40% in patients with a previous history of DVT
- risk of pulmnary embolism
- the occurrence of concomitant pulmonary embolism is also variable, from 0.5% to 4% in symptomatic patients, increasing to 33% when a lung scan is performed (2)
A meta-analysis has examined the relationship between SVT and risk of DVT/PE (3):
- weighted mean prevalence (WMP) of DVT and PE was calculated by use of the random effect model
- results Twenty-one studies (4358 patients) evaluated the prevalence of DVT and 11 studies (2484 patients) evaluated the prevalence of PE in patients with SVT
- WMP of DVT at SVT diagnosis was 18.1% (95%CI: 13.9%, 23.3%)
- WMP of PE was 6.9% (95%CI: 3.9%, 11.8%)
What is the risk of developing a subsequent DVT/PE after an isolated SVT?
- a study compared the incidence of subsequent SVT/DVT/PE after an isolated SVT (iSVT) versus the incidence of SVT/DVT/PE after a proximal DVT
- findings were that "... a first iSVT without cancer...the incidence of deep-VTE recurrence is half that of DVT patients, but the overall risk of recurrence is similar "
- as compared with proximal DVT patients, iSVT patients had a similar overall incidence of VTE recurrence (5.4% per patient-year [PY] versus 6.5% per PY, adjusted hazard ratio [aHR] 0.9, 95% confidence interval [CI] 0.5-1.6),
- iSVT recurred six times more often as iSVT (2.7% versus 0.6%, aHR 5.9, 95% CI 1.3-27.1) and 2.5 times less often as deep-VTE events (2.5% versus 5.9%, aHR 0.4, 95% CI 0.2-0.9)
- saphenous junction involvement by iSVT was not associated with a higher risk of recurrence (5.2% per PY versus 5.4% per PY), but was associated with recurrence exclusively as deep-VTE events (ie a DVT or PE)
- varicose vein status has no impact or a low impact on VTE recurrence
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