Long-term management of deep vein thrombosis based on medical history - A prospective cohort analysis

Introduction: The localization of deep vein thrombosis of the lower legs (DVT) is an important criterion for the management of anticoagulation. Patients (pts) with spontaneous proximal DVT qualify for long-term anticoagulation, whereas pts with distal DVT, namely calf vein DVT without involvement of the popliteal vein, most often can be managed with a shorter anticoagulation. Physicians who decide on the duration of anticoagulation might differ from those who treated the acute DVT. We investigated whether physicians can rely on pts knowledge of DVT localization in the long-term management of DVT.

Method: Outpatients≥18 y who suffered from DVT without pulmonary embolism during the last 10 years were included in the study and were asked about their history of DVT. Proximal DVT was defined as involving the popliteal, femoral, iliac veins or V. cava; distal DVT as involving deep veins below the popliteal vein. The initial doctor`s radiological report (sonography/phlebography/CT/MRI) was requested and was compared with the results gained from anamnesis. Determinants for misclassification of DVT by anamnesis were investigated by regression analysis.

Results: We recruited 196 pts who reported 228 DVT. 26/196 (13.3%) were excluded because it was impossible to obtain the initial doctor`s report, 7 (3.6%) because the report was not informative. Finally, 163 pts with a median age of 49 y, range 22-84 (85 females/78 males) with 177 DVT were included in the analysis. According to the initial doctor`s report, 109 DVT (61.6%) were proximal, 61 (34.5%) distal (12 muscle vein thromboses). Misclassification of DVT localization by anamnesis occurred in 39/177 (22.0%) DVT (kappa coefficient: 0.53). 31/39 (79.5%) misclassifications concerned proximal DVT (21 popliteal, 10 femoral), reported as distal DVT by the pts. In 3 cases the doctor`s report revealed that the reported DVT was a phlebitis and in 4 cases just a follow-up sonography of a DVT. One distal DVT was reported as proximal DVT. In 8/177 additional cases (4.5%) the pts were not informed that their distal leg DVT was a muscle vein thrombosis.In univariate regression analysis we found a significant association between misclassification of DVT and pts age, localization of DVT, number of reported DVT, and provoking factors (spontaneous vs. risk-associated). Sex, interval between DVT and anamnesis, physicians taking anamnesis (n=8), method used to diagnose DVT, and initial treatment as inpatient or outpatient had no significant impact on misclassification (all p>0.19). In multivariate regression analysis, DVT localization was the only independent predictor of misclassification (p<0.001). Proximal DVT was 23-fold more likely to be misclassified by anamnesis than distal DVT (p=0.002).

Conclusion: Anamnesis resulted in misclassification of DVT localization in more than every 4th case. Proximal DVT are prone to be misclassified. Knowledge of the initial radiological report is crucial to avoid false decisions in the long-term management of DVT.

 

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Conflict of Interest:

None

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Artikel online veröffentlicht:
13. Februar 2025