Evaluation of the Influence of Body Position on the Inferior Vena Cava (IVC) Diameter

Study Overview
=================
Brief Summary
-----------------
To determine if laying down or standing up changes the diameter of the inferior vena cava.

Detailed Description
-----------------
Patients are referred for IVC(inferior vena cava)filter placement secondary to trauma, surgery, a fractured pelvis or known blood clots in the lower extremities. The filter is placed to prevent blood clots from traveling into the lungs. The filters are placed during a interventional radiology procedure. During the procedure the diameter of the IVC(inferior vena cava)is measured with the patient in a horizontal position (laying down). The blood pressure in the IVC when a patient is in this position is relatively low in normal circumstances, but may increase substantially when the patient is vertical with secondary dilation of the IVC(inferior vena cava). Migration of IVC(inferior vena cava)filters is not frequent; however it is a serious complication, which may be caused by changes in the diameter of the IVC(inferior vena cava)related to changes in the position of the body and/or increased pressure in the abdomen. The purpose of this study is to evaluate how much postural changes of the body affect the diameter of the IVC(inferior vena cava). For research purposes patients will have an intravascular ultrasound (IVUS) performed to measure the IVC diameter before and after a Valsalva maneuver (having the subject hold their breath and bear down as if they were having a bowel movement). The angiographic table will be elevated and the measurements will be repeated.

Official Title
-----------------
Evaluation of the Influence of Body Position on the Inferior Vena Cava (IVC) Diameter

Conditions
-----------------
Vena Cava Filters

Intervention / Treatment
-----------------
* Procedure: Subjects scheduled for IVC filter placement


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: 18 years of age and older Subjects who will have a clinically indicated IVC filter placement procedure scheduled. Only subjects with no contraindications to being elevated up to a standing or near standing position on the angiography table. - Exclusion Criteria: Pregnant Have a broken leg or any other physical condition that won't allow you to stand. If you are in a traction device If you have a brain injury and require special monitoring of the pressure in the brain. Patients on a ventilator cannot participate in this study. -

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Subjects scheduled for IVC filter placement<br>A filter may be needed to be placed in the IVC (inferior vena cava) to prevent blood clots from traveling from legs to lungs. Patients who have had a pelvic fracture, or have blood clots in the leg(s) may need an IVC. Filter placement may be ordered when a patient is scheduled for major surgery and extensive bed rest. | Procedure: Subjects scheduled for IVC filter placement<br>* Subjects will have an intra vascular ultrasound (IVUS) performed while lying down on the exam table; this will be performed before and after the IVC (inferior vena cava) filter is placed. During the ultrasound, measurements of the diameter of different areas of the IVC will be taken. The table will then be moved so that you are in a standing position and the measurements will be taken again. The ultrasound will be done by the physician performing your procedure. When you are lying down, a sheath (small catheter) will be inserted into a vein in your groin. The IVUS (intra vascular ultrasound) catheter will be inserted through the sheath and used to measure the size of the IVC at various places. The IVUS procedure will add about 30-45 minutes to the filter placement procedure.<br>* Other names: IVUS(intra vascular ultrasound);|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Body postural changes and the effect on the diameter of the inferior vena cava. | Migration of IVC filters is not frequent; however it is a serious complication, which may be caused by changes in the diameter of the IVC related to changes in the position of the body and/or increased pressure in the abdomen. The purpose of this study is to evaluate how much postural changes of the body affect the diameter of the IVC. | 45 minutes |