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Allastair B. Karmody Award. Calf vein thrombi are not a benign finding
J M Lohr1, K V James, R M Deshmukh
1John J. Cranley Vascular Laboratory, Good Samaritan Hospital, Cincinnati, Ohio 45220, USA.
Insights
Calf vein thrombi can propagate proximally, challenging the belief that distal lower extremity thrombosis is benign. This study identified risk factors for thrombus extension in patients with isolated calf vein thrombi.
Area of Science:
- Vascular Medicine
- Diagnostic Imaging
Background:
- Lack of consensus exists regarding risk stratification for proximal propagation of calf vein thrombi.
- Isolated calf vein thrombi require further investigation to predict patient outcomes.
Purpose of the Study:
- To identify risk factors predicting proximal propagation in patients with isolated calf vein thrombi.
- To evaluate the natural history of distal lower extremity thrombosis.
Main Methods:
- Serial duplex scans were performed on 192 patients with isolated calf vein thrombi.
- Risk factors, symptoms, and prophylaxis were analyzed to compare patients with and without thrombus propagation.
Main Results:
- Twenty-eight percent of patients experienced thrombus propagation.
- No statistically significant risk factors, symptoms, or prophylaxis were found to predict propagation.
- Heparin treatment in 23 patients resulted in propagation in only 3, none reaching the knee.
Conclusions:
- Distal lower extremity thrombosis may not be as benign as previously assumed.
- The potential for proximal propagation necessitates careful monitoring of calf vein thrombi.
Background:
Currently, there is no consensus in the literature regarding which patients with calf vein thrombi are at high risk for proximal propagation. This study examined patients with isolated calf vein thrombi with serial duplex scans in order to identify risk factors that would predict outcome.
Patients And Methods:
Between May 1989 and November 1994, 288 patients were identified with isolated calf vein thrombi. One hundred ninety-two of them had sequential scans performed.
Results:
Fifty-three (28%) of the 192 patients had propagation of their initial thrombi. The most proximal level of propagation was the popliteal vein in 11 patients, the superficial femoral vein in 5, the common femoral vein in 5, adjacent tibial or soleal veins in 24, adjacent soleal veins alone in 7, and the lesser saphenous vein in 1. Three patients whose thrombi propagated had free-floating thrombus tips in the large veins of their thighs. Symptoms, prophylaxis, and risk factor analysis comparing those patients whose thrombi propagated to those whose thrombi did not found no statistically significant prognostic value. Single or multiple calf vein thrombi did not predict propagation. Of the 23 patients treated with heparin, only 3 had thrombus propagation. None of these reached the level of the knee (including popliteal vein).
Conclusions:
The natural history of distal lower extremity thrombosis does not appear to be as benign as previously believed.