Are routine inferior vena cavograms necessary before Greenfield filter placement?

In August 1983 we began routinely studying the inferior vena cava (IVC) before placement of a Greenfield filter. We have performed 83 caval interruptions since that time, but six patients were excluded from this study because an IVC clip had been placed in three patients during other abdominal surgery, and the medical records of three others could not be retrieved. Of the remaining 77 patients, 65 (84%) had IVC venograms taken before placement of their filter. We personally reviewed 63 of these cavograms but had to accept the radiologist's reports for two studies that could not be retrieved. Ten (15%) cavograms showed abnormalities that significantly affected the placement of the filter. The most frequent abnormality was intracaval clot extending above the L3-4 interspace. Other important abnormalities were severe narrowing of the diaphragmatic IVC (two patients) and a tortuous IVC in a patient with severe scliosis. Seven (11%) additional cavograms showed unilateral iliac thrombus that would have influenced the surgical approach had a femoral approach been required. Formal preoperative cavography expedited filter placement and reduced operating time by obviating the need for intraoperative angiograms. Because 26% of the cavograms showed clinically important information, we recommend that routine IVC angiograms be taken before filter placement.