Detailed assessment of benefits and risks of retrievable inferior vena cava filters on patients with complicated injuries: the da Vinci multicentre randomised controlled trial study protocol

Abstract

IntroductionRetrievable inferior vena cava (IVC) filters have been increasingly used in patients with major trauma who have contraindications to anticoagulant prophylaxis as a primary prophylactic measure against venous thromboembolism (VTE). The benefits, risks and cost-effectiveness of such strategy are uncertain.Methods and analysisPatients with major trauma, defined by an estimated Injury Severity Score >15, who have contraindications to anticoagulant VTE prophylaxis within 72 hours of hospitalisation to the study centre will be eligible for this randomised multicentre controlled trial. After obtaining consent from patients, or the persons responsible for the patients, study patients are randomly allocated to either control or IVC filter, within 72 hours of trauma admission, in a 1:1 ratio by permuted blocks stratified by study centre. The primary outcomes are (1) the composite endpoint of (A) pulmonary embolism (PE) as demonstrated by CT pulmonary angiography, high probability ventilation/perfusion scan, transoesophageal echocardiography (by showing clots within pulmonary arterial trunk), pulmonary angiography or postmortem examination during the same hospitalisation or 90-day after trauma whichever is earlier and (B) hospital mortality; and (2) the total cost of treatment including the costs of an IVC filter, total number of CT and ultrasound scans required, length of intensive care unit and hospital stay, procedures and drugs required to treat PE or complications related to the IVC filters. The study started in June 2015 and the final enrolment target is 240 patients. No interim analysis is planned; incidence of fatal PE is used as safety stopping rule for the trial.Ethics and disseminationEthics approval was obtained in all four participating centres in Australia. Results of the main trial and each of the secondary endpoints will be submitted for publication in a peer-reviewed journal.Trial registration numberACTRN12614000963628; Pre-results.

Cost-effectiveness of early placement of vena cava filters to prevent symptomatic pulmonary embolism in patients with contraindications to prophylactic anticoagulant

“…It is well-established that DVT and PE can have long-term consequences affecting patients' quality of life, their ability and time taken to return to work, and hence also productivity for the society as a whole. [1][2][3] Furthermore, although our a priori subgroup was prespecified in our trial design 6,8 and we also adjusted our analysis of this subgroup by Bonferroni-correction, survivor bias may still exist, which may have inflated the potential benefit of the filter in preventing PE among those who survived longer than 7 days after study enrolment. 8…”

“…5 The da Vinci multicenter randomized controlled trial (RCT) was conducted to address this perplexing issue, by assessing if placement of a retrievable vena cava filter in trauma patients with a contraindication to standard prophylactic anticoagulant within 72 hours of admission would reduce the composite endpoint of mortality or symptomatic PE. [6][7][8] Because vena cava filters are expensive, the cost-effectiveness of using a vena cava filter to prevent symptomatic PE − including the costs of the filter and the procedures to implant and retrieve the device, complications related to the filter, procedures needed to diagnose and treat DVT and PE, total length of intensive care unit (ICU) and hospital stay, procedures and drugs needed to treat bleeding complications − was also a primary endpoint of this trial. 6 We hypothesized that if vena cava filters are effective in reducing PE in trauma patients without known venous thromboembolism and the incidence of PE is sufficiently high, using a vena cava filter as a primary means to prevent symptomatic PE may reduce the net total healthcare cost, or at least be cost neutral.…”

“…[6][7][8] Because vena cava filters are expensive, the cost-effectiveness of using a vena cava filter to prevent symptomatic PE − including the costs of the filter and the procedures to implant and retrieve the device, complications related to the filter, procedures needed to diagnose and treat DVT and PE, total length of intensive care unit (ICU) and hospital stay, procedures and drugs needed to treat bleeding complications − was also a primary endpoint of this trial. 6 We hypothesized that if vena cava filters are effective in reducing PE in trauma patients without known venous thromboembolism and the incidence of PE is sufficiently high, using a vena cava filter as a primary means to prevent symptomatic PE may reduce the net total healthcare cost, or at least be cost neutral. 9 This result is achievable, at least theoretically, when the incremental cost of the filter and the costs of the procedure to insert and retrieve the device are offset by the saving achieved by having fewer symptomatic PE and associated complications.…”

“…6–8 Because vena cava filters are expensive, the cost-effectiveness of using a vena cava filter to prevent symptomatic PE − including the costs of the filter and the procedures to implant and retrieve the device, complications related to the filter, procedures needed to diagnose and treat DVT and PE, total length of intensive care unit (ICU) and hospital stay, procedures and drugs needed to treat bleeding complications − was also a primary endpoint of this trial. 6…”

Femoral venous catheterisation, lower limb pneumatic compression and venous thromboembolism after severe trauma: A substudy of the da Vinci trial

“…We hypothesised that femoral venous catheterisation and omitting bilateral lower limb pneumatic compression were significant, and potentially modifiable, mechanical risk factors for developing venous thromboembolism in patients with severe trauma. In this substudy of the da Vinci trial, 4,5 we report the associations between the use of femoral venous catheterisation or lower limb pneumatic compression and venous thromboembolism.…”