Clinical experience with the Mobin-Uddin vena cava umbrella filter.

The Mobin-Uddin vena cava filter has been used at Boston University Medical Center since 1971. The umbrella filter has been placed in 128 high-risk patients with a mean age of 60 years, 42% of whom had malignancies. The operative morbidity consists of five wound hematomas, one misplaced umbrella, one retroperitoneal hematoma, and one acute vena cava occlusion, with a total operative morbidity of 6.2%. No patients died of the actual pacement, and the 30-day hospital mortality was 7.0%. Late sequaelae included an incidence of mild edema of 6% and severe edema of 16%. We know of no patients in our series who had recurrent pulmonary embolism. In our experience, the Mobin-Uddin vena cava umbrella filter is a safe, effective method of vena cava interruption in a high-risk population with a low operative morbidity and a low 30-day mortality.

Evaluation and management of vascular injuries of the extremities.

We reviewed our experience with 315 extremity injuries in 306 patients for the possibility of accurately evaluating the presence of a potential vascular injury. Indications for surgical exploration based on the clinical finding of a bruit and/or thrill, ischemia, absent, pulse, shock, hemorrhage, neurologic deficit, hematoma, and proximity resulted in a rate of positive surgical exploration results of between 20% and 100%. Angiography was performed in 65 patients; 24 angiograms showed vascular injury and 41 did not. Angiography for proximity alone revealed 12% abnormal finding. Operative morbidity in the surgically explored group was 2%. We developed an algorithm for the treatment of these patients.

Lower gastrointestinal bleeding. Diagnostic approach and management conclusions.

The management of patients with lower gastrointestinal bleeding requires a systematic approach based on defined diagnostic and therapeutic methods. Although in 80 percent of patients bleeding will stop spontaneously, 25 percent will have rebleeding and 50 percent of those with rebleeding will bleed again. Angiography documents specific bleeding sites but raises questions related to the incidence, site and frequency of bleeding, as well as the necessity of demonstrating extravasation. We reviewed 49 arteriograms performed for lower gastrointestinal bleeding. We conclude from our findings that angiography identifies a presumptive cause of bleeding in 49 percent of patients; angiography identified the site of bleeding in 86 percent of the patients with active bleeding, thus allowing segmental colectomy. We believe that documentation of angiodysplasia in a patient with lower gastrointestinal bleeding is presumptive evidence for the site of bleeding. Angiography is useful and worthwhile in the work-up of patients with lower gastrointestinal bleeding in an attempt to plan localized, definitive resection, and this may lead to a lower mortality rate.

Technical modifications in the placement of inferior vena caval filter devices.

Placement of 151 Mobin-Uddin vena caval umbrella filters and 17 Kimray-Greenfield vena caval filters since 1972 led us to make a number of technical modifications. The operative procedure is performed with local anesthesia in the vascular radiology suite. If the right internal jugular vein is narrowed and cannot be dilated, an approach through the left internal jugular vein is possible. The filters are advanced under fluoroscopic control after direct visualization of both renal veins. Since the patient is awake, he can be asked to roll on the left side if there is a tendency for the filter to advance into the hepatic veins or the right renal vein. Release of the filter is most accurately accomplished by withdrawing the carrier rather than advancing the filter. The carrier is then removed under fluoroscopic control and the internal jugular vein ligated. These modifications have resulted in a success rate of nearly 100 percent in recent filter placements, an operative morbidity of 8.3 percent and a 30 day hospital mortality of 8.9 percent.

Management of vascular injuries to the leg.

Our experience with 69 vascular injuries in 56 patients led us to modify the management of vascular injuries to the leg. We believe that prompt and complete angiography whenever the general condition of the patient allows it, early fasciotomy when indicated before vascular repair, thrombectomy of the injured artery and vein and local instillation of heparinized saline solution, vascular repair before orthopedic stabilization of fractures in selected cases, external fixation of the fracture when there is significant soft tissue injury, and early skin grafting resulted in an improved level of care with a low morbidity and no mortality in our series.

A complication following Kimray-Greenfield filter insertion.

The Kimray-Greenfield inferior vena cava filter, which is used to prevent pulmonary embolization from the pelvis and lower extremities, has a high patency rate and a low complication rate. In one patient, however, thrombus formation at the apex of the filter during introduction resulted in the filter's failure to open completely so that the entire width of the cava in the transverse diameter was not occluded. This potential complication may be avoided by keeping the introduction time to a minimum and by constantly infusing a heparin solution through the side port of the insertion device while it is in the vena cava.

Use of a guide wire snare for placement of vena cava filters.

A guide wire snare was used to facilitate passage of a Mobin-Uddin vena cava filter through a tortuous left innominate vein, and a Kimray-Greenfield vena cave filter from the suprarenal into the infrarenal position of the inferior vena cava.

Detection of a traumatic renal arterial venous fistula by radionuclide angiography (RNA).

Radionuclide angiography is a valuable screening test for arteriovenous (AV) fistulas. A case is presented of a young man with a post-traumatic AV fistula involving the renal artery and vein initially diagnosed by radionuclide imaging and subsequently confirmed by angiography. In the patient described dynamic flow studies showed concentration at the site of an AV fistula which was successfully treated operatively. We now recommend radionuclide angiography in patients with penetrating abdominal trauma and unexplained abdominal findings.