Stuart Lyon

Infusion of Reconstituted High-Density Lipoprotein Leads to Acute Changes in Human Atherosclerotic Plaque

Studies have shown a reduction in plaque volume and change in plaque ultrasound characteristics after 4 infusions of reconstituted high-density lipoprotein (rHDL). Whether rHDL infusion leads to acute changes in plaque characteristics in humans is not known. Patients with claudication scheduled for percutaneous superficial femoral artery revascularization were randomized to receive 1 intravenous infusion of either placebo or rHDL (80 mg/kg given over 4 hours). Five to 7 days following the infusion, patients returned and revascularization was performed including atherectomy to excise plaque from the superficial femoral artery. Twenty patients (17 males) average age, 68±10 years (mean±SD) were recruited. Eleven patients had a history of documented coronary artery disease, all patients were on aspirin, and 18 were on statins. Ten of the patients received rHDL and 10 placebo. There was significantly less vascular cell adhesion molecule-1 expression (28±3% versus 50±3%; P<0.05) and a reduction in lipid content in the plaque of HDL-treated subjects compared to placebo. The level of HDL cholesterol increased by 20% after infusion of rHDL and the capacity of apolipoprotein B–depleted plasma to support cholesterol efflux increased. Intravenous infusion of a single dose of reconstituted HDL led to acute changes in plaque characteristics with a reduction in lipid content, macrophage size, and measures of inflammation. These changes may contribute to the cardioprotective effects of HDL.

Short- and long-term retrievability of the Celect vena cava filter: Results from a multi-institutional registry

PURPOSE To evaluate retrievability of the Celect vena cava filter over time and to assess the safety of the retrieval procedure in a prospective multicenter registry. MATERIALS AND METHODS Between October 2005 and March 2008, Celect filters were placed in 95 patients (61 men; mean age, 51 years +/- 18.5) with a temporary need for an inferior vena cava (IVC) filter. All patients satisfied requirements for filter placement; the primary indications for placement were pulmonary embolism (PE) with a contraindication to or failure of anticoagulation (n = 40), high risk for further PE (n = 29), trauma (n = 23), or massive PE with residual deep vein thrombosis and risk for further PE (n = 3). Filter orientation, vena cava injury, and other device-related incidents were evaluated at implantation and retrieval. The degree of difficulty associated with retrieval was also assessed. RESULTS Filter retrieval was attempted in 58 patients (mean indwell time of 179 days; median, 168.5 d; range, 5-466 d). Fifty-six filters (96.6%) were successfully retrieved. Unsuccessful retrieval attempts were attributed to filter tilt (n = 1) or excessive tissue growth with the hook embedded in the endothelium (n = 1). No adverse events were associated with the inability to retrieve these filters. A Kaplan-Meier product-limit survival estimate revealed that the probability of successful filter retrieval remained at 100% at 50 weeks and at more than 74% at 55 weeks after implantation. No adverse events were related to the retrieval procedures. CONCLUSIONS Retrieval of the Celect filter was performed safely as long as 466 days after implantation.

Extremities-Indications and techniques for treatment of extremity vascular injuries

Traumatic vascular injuries involving the extremity are rare and penetrating trauma accounts for the majority of such injuries. The remaining arterial injuries are as a result of either blunt or iatrogenic injuries. The rapid detection, localisation and characterisation of vascular injuries in patients who have a traumatic extremity injury is essential for the effective management and treatment of such injuries. This review will discuss the expanding role of multi-detector computed tomography angiography in diagnosing vascular injuries and its implications on conventional diagnostic angiography. The roles of other non-invasive imaging modalities are reviewed. The presentation and types of vascular injuries in blunt and penetrating injuries are discussed. While surgery remains the gold standard in the management of vascular extremity injuries it has significant morbidity rates. Endovascular techniques are increasingly being used for the treatment of vascular traumatic injuries and various techniques including balloon occlusion, embolisation and stent/stent graft placement are discussed.

Initial experience in 115 patients with the retrievable Cook Celect vena cava filter

The aim of this study was to evaluate our experience with the retrievable Cook Celect inferior vena cava (IVC) filter (William Cook, Europe) with regard to insertion, efficiency, ease of retrieval, and any associated complications. A retrospective review was performed of 115 patients (41 female, 74 male, mean age 47.97 years) who underwent Cook Celect IVC filter insertion between December 2005 and October 2007. Filter insertion was successful in all patients. Of the 115 filters inserted, 57 have been successfully retrieved (49.6%) to date. The successful retrieval rate from attempted retrieval was 93.4%. The mean dwell time of successfully retrieved filters was 114.9 days (range 14–267 days). Failed retrievals were due to a thrombosed vena cava (n = 1) and endothelialisation of the filter (n = 3). In the failed retrieval group the mean implantation time was 142 days (range 78–211 days). While this is the first retrospective clinical study on the Cook Celect filter, results to date are promising. We demonstrated an efficacious filter with a high successful retrieval rate of 93.4% and a low complication rate. The filter was assessed with extended dwell times (range 14–267 days). Failed retrieval secondary to hook endothelialisation continues to be an issue with this filter. We recognize that a limitation of our study was the lack of systematic follow‐up for clinically silent complications. Further studies to evaluate longer term outcomes and effectiveness of this filter are warranted.

Retrievable Gunther Tulip inferior vena cava filter: Experience in 317 patients

The aim of our study was to assess our experience with the retrievable Gunther Tulip (GT) inferior vena cava (IVC) filter, with regard to its insertion, efficacy, ease of placement and retrieval, and associated complications. Between November 2001 and October 2005, 322 GT filters were placed in 317 patients. Insertion indications included the following: pulmonary embolus (PE) prophylaxis in trauma patients (n = 232), PE prophylaxis in perioperative patients (n = 27), PE prophylaxis in moribund intensive care unit patients (n = 22), recent PE (n = 48), extensive deep venous thrombosis (n = 66), contraindication to anticoagulation (n = 63), anticoagulation complication (n = 8) and deep venous thrombosis with failed anticoagulation (n = 8). Some patients had more than one indication for caval filter placement. Two hundred and five attempted retrievals have been carried out, with 15 failures. Our successful retrieval rate is 92%. Nineteen filters were originally inserted permanently. There have been three minor complications associated with insertion and five with retrieval. The mean time from filter insertion to attempted retrieval was 76.95 days. The ideal filter implantation time gives the patient the benefit of PE protection, while avoiding the long‐term risks associated with caval filters. Although GT retrieval times have lengthened considerably, our data suggest that this is at the expense of successful retrieval rates.

Embolization of Spontaneous Hemarthrosis Post Total Knee Replacement

Spontaneous nonhemophiliac hemarthrosis is an unusual entity, which has been little described. We present three cases of spontaneous recurrent hemarthrosis post total knee replacement (TKR) and successful management with embolization. Three male patients were referred to our service for angiography and treatment of recurrent hemarthrosis post TKR. In all three patients antegrade ipsilateral common femoral artery punctures and selective angiography of the geniculate branches were performed with a microcatheter. Abnormal vasculature was noted in all cases. Subsequent embolization was performed with Contour (Boston Scientific, Target Vascular, Cork, Ireland) embolization particles (150–250 and 250–355 μm) in two patients and microcoils in the third (TornadoR; Cook Inc., Bloomington, IN, USA). Technical success was 100%. One patient had a recurrence of symptoms requiring a repeat procedure 6 months later. No complications were encountered. Selective angiography and particle embolization is an effective technique for management of this unusual but problematic postoperative sequelae.

Variant treatment for gastric varices with polidocanol foam using balloon‐occluded retrograde transvenous obliteration: A pilot study

Treatment of gastric variceal rupture remains difficult with current options including transjugular intrahepatic portosystemic shunt and endoscopic therapies having significant side effects or reduced efficacy. We report five cases of gastric varices that were successfully treated with balloon‐occluded retrograde transvenous obliteration of varices (BRTO) using Polidocanol foam as an alternative sclerosant to ethanolamine oleate.

Interventional radiology in the provision and maintenance of long‐term central venous access

Establishing and maintaining venous access forms an increasing proportion of the workload in interventional radiology. Several patient groups require medium‐term to long‐term venous catheters for a variety of purposes, including chemotherapy, long‐term antimicrobials, parenteral nutrition, short‐term access for haemodialysis or exhausted haemodialysis. Often, these catheters are required for treatment and frequent blood testing, which can quickly exhaust the peripheral veins. Long‐term venous access devices minimize the discomfort of frequent cannulation while preserving the peripheral veins. Venous access devices include implantable catheters (ports), tunnelled catheters and peripherally inserted central catheters, which have different functions, advantages and limitations. Imaging‐guided placement is the preferred method of insertion in many institutions because of higher success rates and radiologists are well suited to address catheter complications.

Fibromuscular Dysplasia Presenting with Bilateral Renal Infarction

Fibromuscular dysplasia (FMD) describes a group of conditions which cause nonatheromatous arterial stenoses, most commonly of the renal and carotid arteries, typically in young women. We report a rare case of bilateral segmental renal infarction secondary to FMD in a young male patient. His initial presentation with loin pain and pyrexia resulted in a delay in the definitive diagnosis of FMD. He was successfully treated with bilateral balloon angioplasty. The delayed diagnosis in this patient until the condition had progressed to bilateral renal infarcts highlights the need for prompt investigation and diagnosis of suspected cases of FMD.

Pulmonary embolism and the use of vena cava filters after major trauma

Major trauma patients are at significant risk of developing pulmonary embolism (PE). We aimed to (i) analyse the current incidence and timing of PE after injury; (ii) identify risk factors that predispose major trauma patients to the occurrence of PE; and (iii) describe the use of vena cava filters (VCFs) following major trauma.