Gurmeen Kaur, MBBS
With the advent of the endovascular era for ischemic strokes, the role for endovascular therapy for cerebral venous thrombosis (CVT) has been approached with growing interest. However, anticoagulation continues to be the mainstay of treatment for CVT.
In this interesting meta-analysis, de Sousa et al reviewed recanalization rates, clinical outcomes and recurrence rates in patients with CVT.
A total of 468 studies were screened, of which 19 were identified after excluding those studies which had pediatric patients, in which >10% of individuals had endovascular treatment and in whom anticoagulation was not used as part of the post-operative treatment plan.
Imaging follow-up was MRI-based and was characterized into complete, partial or no recanalization. Clinical outcome was dichotomized as good and bad using the modified Rankin scale (mRS). The 19 studies included a total of 818 patients with recanalization data after CVT ranging from 10 to 125 patients per study. 7 of 19 were moderate quality, and the others were poor quality. Most of the studies were retrospective cohort studies (11/19).
Recanalization was achieved in 694 of 818 patients, which is an overall rate of 85%. Among the dataset available, 720 patients had data on extent of recanalization, and complete recanalization was seen in 49%, partial recanalization in 35%.
Timing of recanalization is another critical question that the meta-analysis tried to answer. Among the 300 plus patients with data available on timing of recanalization, the overall recanalization rate tended to increase with time ≤9 months, from 33% to >80%. More than 3/4th (79%) of the patients had already achieved recanalization at the 3-month mark. Thrombosis of the superior sagittal sinus and female sex were reported as positive predictors of successful recanalization, whereas multiple thrombosis, hormonal therapy, older age, and lack of identified risk factors for CVT were negative predictors of recanalization.
About half the data-set had information on mRS which was favorable (mRS 0-1) in 89% of those with recanalization and 71% of those without recanalization. The overall rate of recurrence was higher in patients without recanalization (3.4% versus 0.9%).
The study has several limitations inherent to the meta-analysis study design. Additionally, limited data is available on outcomes, risk factors and standardized timing of imaging. Also, most studies used MR-based follow-up, so the results may not be generalizable to a CT-based population.
Despite its limitations, the study does show us that anticoagulation for CVT can achieve recanalization up to 85% of times, nearly 3/4th clots should resolve within 3 months and MR-based follow-up can successfully be used. Additionally, lack of venous recanalization is associated with worse functional outcome in patients with CVT receiving anticoagulation.