Medical literature and vena cava filters: so far so weak.

STUDY

OBJECTIVE

With the development of percutaneous inferior vena cava (IVC) filters, IVC interruption has become a widely used procedure in patients with or at risk for venous thromboembolism. In an attempt at clarifying the indications for filter placement, a systematic literature review was undertaken.

DESIGN

Bibliographic search and analysis.

MEASUREMENTS AND

RESULTS

A systematic MEDLINE search about vena cava filters produced a total of 568 references with abstracts between 1975 and 2000 inclusively. Each reference was analyzed according to predetermined criteria. Nearly two thirds (65.0%) of these publications were retrospective studies or case reports (33.3 and 31.7%, respectively), 12.9% were animal or in vitro studies, 7.4% were prospective studies, 6.7% were reviews, and 8.1% reported on miscellaneous related topics. Among the prospective studies, only 16 studies included > or = 100 patients, only 1 study was a randomized controlled trial (0.02% of 568 references), and heterogeneity among series precluded any relevant comparison. In a similar search about heparin and venous thromboembolism, 47.4% of 531 references were randomized controlled trials.

CONCLUSIONS

Until more relevant data become available, literature reviews about vena cava filters will remain narrative, and many if not most indications for filter placement will remain a matter of opinion.