What are the landmark trials related to Inferior Vena Cava (IVC) filters?

Landmark Trials Related to Inferior Vena Cava Filters

PREPIC (Prévention du Risque d'Embolie Pulmonaire par Interruption Cave) Trial

The PREPIC trial remains the most important randomized controlled trial evaluating IVC filters, demonstrating that while filters reduce pulmonary embolism, they increase deep vein thrombosis without improving survival. 1

Key Findings from PREPIC:

• 400 patients with iliofemoral DVT at high risk for PE were randomized to receive permanent IVC filters plus anticoagulation versus anticoagulation alone 1
• At 12 days, PE occurred in 1.1% with filters versus 4.8% without filters (P=0.03) 2
• At 8 years follow-up, PE rates were 6.2% with filters versus 15.1% without filters 2
• However, DVT recurrence at 2 years was significantly higher with filters: 20.8% versus 11.6% 1, 2, 3
• No mortality benefit was demonstrated at any time point—12-day mortality was identical at 2.5% in both groups 2
• At 8-year follow-up, there remained no survival difference despite sustained PE reduction 2

Critical Limitation:

The PREPIC trial evaluated filters plus anticoagulation versus anticoagulation alone, which does not address the most common clinical scenario where filters are used: patients who cannot receive anticoagulation 1

PREPIC II Trial

PREPIC II specifically evaluated retrievable IVC filters and found no benefit over anticoagulation alone. 1

Key Findings from PREPIC II:

• Recurrent PE occurred in 3% with retrievable filters plus anticoagulation versus 1.5% with anticoagulation alone (RR 2.0; 95% CI 0.51-7.89)—no significant difference 1
• This trial reinforced that routine filter placement in patients who can be anticoagulated provides no clinical benefit 1

Major Trauma Studies

Multiple trauma studies have failed to demonstrate benefit from prophylactic IVC filter placement. 1

Key Findings:

• A multicenter trial in severely injured trauma patients showed filters did not reduce symptomatic PE or death: 13.9% with filters versus 14.4% without filters (HR 0.99; 95% CI 0.51-1.94; P=0.98) 1
• A systematic review and meta-analysis by Haut et al. (2014) found prophylactic IVC filters in trauma patients did not improve outcomes 1
• Hemmila et al. (2015) demonstrated that prophylactic IVC filter placement does not result in survival benefit for trauma patients 1

Cancer-Associated VTE Studies

The Barginear trial evaluated IVC filters specifically in cancer patients with VTE. 1

Key Finding:

• This prospective randomized trial investigated adding a vena cava filter to fondaparinux anticoagulation in cancer patients with VTE 1
• The study reinforced that standard indications for filter placement apply to cancer patients, with no routine use recommended 1, 3

Meta-Analyses and Systematic Reviews

Recent meta-analyses have provided pooled evidence on IVC filter outcomes across multiple trials. 4

Key Findings from 2021 Meta-Analysis:

• Seven randomized controlled trials with 1,274 patients were pooled 4
• No significant difference in PE-related mortality between IVC filter and control groups (risk difference -0.01; 95% CI -0.03 to 0.00; P=0.11) 4
• New PE occurrence was lower with filters within 3 months (0.81% vs 5.98%; RR 0.17; P=0.01) and during entire follow-up (3.2% vs 7.79%; RR 0.42; P=0.001) 4
• No significant differences in deep vein thrombosis, major bleeding, or overall mortality 4

Bariatric Surgery Studies

Systematic reviews have evaluated prophylactic filter use in bariatric surgery patients. 1

Key Finding:

• Brotman et al. (2013) conducted a systematic review and meta-analysis of pharmacologic and mechanical strategies for preventing VTE after bariatric surgery, finding insufficient evidence to support routine prophylactic filter placement 1

Common Pitfalls Highlighted by Landmark Evidence:

• The landmark trials consistently demonstrate that IVC filters should never be used routinely in patients who can be anticoagulated 1, 2, 3
• Filters reduce PE but increase DVT without improving survival—this trade-off must be explicitly discussed 1, 2, 3
• The most common clinical indication (contraindication to anticoagulation) has never been tested in a randomized trial 1
• Retrievable filters are frequently left in place permanently despite resolution of contraindications, exposing patients to unnecessary long-term complications 2