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Biomedical subjects

S F Millward

Publications and source records attributed to S F Millward.

At least 19 recordsLinked to original sources
PubMed2001

Günther Tulip Retrievable Vena Cava Filter: results from the Registry of the Canadian Interventional Radiology Association.

PURPOSE: To report data collected by the Canadian Registry of the Günther Tulip Retrievable Filter (GTF). MATERIALS AND METHODS: Between February 1998 and December 2000, 90 patients at eight hospitals underwent implantation of 91 GTFs. There were 45 male patients and 45 female patients, age 17-88 years, with a mean age of 49 years. Indications for filter placement were pulmonary embolism (PE) or deep vein thrombosis (DVT) with a contraindication to anticoagulation in 83 patients, prophylaxis after massive PE in one, prophylaxis for proximal free-floating thrombus in one, and prophylaxis with no DVT or PE in six patients (major trauma, n = 4; high preoperative risk, n = 2). GTF retrieval was attempted in selected patients from a right internal jugular vein approach. RESULTS: One GTF was inadvertently placed in the right iliac vein and could not be retrieved. There were no other major placement complications. GTF retrieval was attempted in 52 patients (53 GTFs); 52 GTFs were successfully retrieved from 51 patients. Implantation times were 2-25 days (mean, 9 d). Of these 51 patients, 37 underwent follow-up for 5-420 days (mean, 103 d) after filter retrieval. Four patients (8% of retrieved GTFs) required reinsertion of a permanent filter 17-167 days (mean, 78 d) after GTF retrieval as a result of bleeding from anticoagulation (n = 2) or because the patient required further surgery (n = 2). One other patient had recurrent DVT 230 days after retrieval; no PE or other complication was documented in the retrieval group. GTFs were not retrieved from 39 patients for various reasons. Of these 39 patients, 25 underwent follow-up 7-420 days (mean, 85 d) after filter placement. Two patients developed filter occlusion (5%); no other complications were documented. CONCLUSION: The GTF has a broad range of utility: it can be used as a permanent filter or retrieved after implantation periods of 15 days and possibly longer. However, indications for retrieval require further study, as does the maximum implantation time.

Adolescent↗
PubMed2001

Femoral artery thrombosis after percutaneous thrombin injection of an external iliac artery pseudoaneurysm.

Ultrasound-guided percutaneous thrombin injection has been developed as a less invasive and highly successful treatment of iatrogenic femoral pseudoaneurysms. Most of these lesions have been the result of catheterization procedures. This method has proved to be highly effective, and few complications have been reported. Specifically, native arterial thrombosis, although recognized as a severe complication, has been mentioned only briefly in the literature. We present a case of the successful management of native arterial thrombosis after attempted percutaneous thrombin injection of a chronic external iliac artery pseudoaneurysm. This case serves to illustrate the risk factors for this complication and the treatment options once it occurs. The success of this treatment with acute iatrogenic femoral pseudoaneurysms may not necessarily translate into similar success in other anatomic locations and clinical situations.

Coagulants↗
PubMed2001

The current status of interventional radiology in Canada: results of a survey by the Canadian Interventional Radiology Association.

OBJECTIVE: To evaluate the current status of interventional radiology in Canada. METHODS: A questionnaire was sent to 28 Canadian interventional radiologists (defined as a physician who performs any type of interventional procedure, including biopsies, but excluding interventional neuroradiology) practising in both tertiary and community hospitals in the major centres in all provinces except Prince Edward Island. RESULTS: Twenty-two (79%) of 28 surveys were completed and returned, providing data about 86 interventional radiologists (IRs). IRs were performing almost all of the following procedures at their institutions: inferior vena cava filter placement, venous angioplasty, dialysis fistula angioplasty, diagnostic and therapeutic pulmonary and bronchial artery procedures, diagnostic and therapeutic procedures of the lower extremity and renal arteries, percutaneous abscess and biliary drainage procedures, percutaneous nephrostomy, and fibroid embolization. A second group of procedures, performed by both IRs and non-radiologists in most institutions, included: all types of central venous catheter placements, pleural drainage, and gastrostomy tube placement. Procedures not being performed by anyone in a number of institutions included: dialysis graft thrombolysis, varicocele embolization, transjugular intrahepatic portosystemic shunts, palliative stenting of the gastrointestinal tract, fallopian tube recannalization, and liver and prostate tumour treatments. The factors most often limiting the respondents' ability to provide a comprehensive interventional service were the interventional radiology inventory budget and the availability of interventional radiology rooms; 50% of respondents indicated the number of available nurses, technologists and IRs was also an important limiting factor. CONCLUSION: IRs in Canada still play a major role in many of the most commonly performed procedures. However, limited availability of resources and personnel in many institutions may be hampering the ability of IRs to develop new procedures.

Canada↗
PubMed2000

Günther Tulip filter: preliminary clinical experience with retrieval.

PURPOSE: The Günther Tulip filter is a permanent filter that has a hook to permit retrieval. The authors report their preliminary clinical evaluation of the filter with regard to feasibility and safety of retrieval. MATERIALS AND METHODS: Nine men and six women who ranged in age from 17 to 79 years (mean, 51 years) underwent treatment with use of the Günther Tulip filter. Patients judged to require caval interruption for < 14 days were selected to receive the filter and retrieval was planned for all patients. Indications for filter placement were: recent pulmonary embolism (PE) or proximal deep vein thrombosis (DVT) with a contraindication to anticoagulation (11 patients), massive PE treated with thrombolytic therapy (one patient), PE with heparin-induced thrombocytopenia (one patient), and prophylaxis after major trauma (two patients). Patients were followed for inferior vena cava (IVC) thrombosis, bleeding, and recurrent DVT or PE. RESULTS: In all nine patients in whom it was attempted, the filter was successfully snared and retrieved via a jugular approach. The mean implantation period was 8.6 days (range, 5-13 days). Retrieval required 2.2-13 minutes (mean 5.3 minutes) of fluoroscopy. No caval injuries occurred as a result of retrieval. All retrieved filters had strands of organized thrombus on the filter struts. The patients were followed for 52-285 days (mean, 115 days) after retrieval. One patient developed a recurrent DVT 230 days after retrieval. No other patients developed a recurrent DVT and no patients developed IVC thrombosis, bleeding, or PE. Six filters were not retrieved: five because of an ongoing contraindication to anticoagulation and one because the patient died of causes unrelated to the filter. CONCLUSION: This preliminary study confirms the feasibility and safety of retrieval of the Günther Tulip filter up to 13 days after implantation.

Adolescent↗
PubMed2000

Outpatient percutaneous transluminal renal artery angioplasty: a Canadian experience.

PURPOSE: The authors performed a retrospective study of their experience and complication rate while performing outpatient percutaneous transluminal renal artery angioplasty (PTRA) during a 5-year period. MATERIALS AND METHODS: From July 1992 to July 1997, 87 PTRAs were performed. Of these, 62 PTRA procedures were performed on 53 outpatients. In total, 66 arteries were dilated in 62 PTRA sessions using standard, established techniques. During the same period, only 25 PTRAs were performed on inpatients. Angioplasties were performed on those patients with demonstrated renal artery stenosis and poorly controlled hypertension and/or renal failure. Patients chosen for PTRA were picked by a team that included a vascular surgeon, a nephrologist, and a radiologist. Patients who were deemed suitable for an outpatient procedure were recommended by a nephrologist. Radiological input was sought at that time. Specific guidelines were used to select these patients who were otherwise healthy, well-orientated, and able to respond to an emergency situation. None of the subjects had significant risk factors. All were accompanied by an adult for the first 24 hours and all lived no more than an hour's travel time from a hospital. All were stable on discharge and were seen within 24 hours by a nephrologist. RESULTS: The technical success rate, defined as a residual stenosis on imaging of less than 30% and/or by a pressure gradient of less than 10 mm Hg across the stenosis, was 85%. The early complication rate was 5.6%, including two patients who developed a localized hematoma. In all, four patients were admitted to the hospital rather than being discharged to home after an average of 4.2 hours of observation. The late complication rate was 3% and involved two patients. One patient, who reported pain after balloon deflation, was readmitted 6 hours after discharge with hypotension, and a diagnosis of renal artery rupture was confirmed with computed tomography. Another patient developed peripheral atheroemboli 20 days after the procedure. CONCLUSION: Outpatient PTRA can be performed on selected patients. In this study, late complications occurred in only 3% of patients. Early complications were readily recognized in 5.6% of patients, and these patients were admitted for observation after the procedure.

Adult↗
PubMed1998

Ureteropelvic junction disruption secondary to blunt trauma: excretory phase imaging (delayed films) should help prevent a missed diagnosis.

PURPOSE: Ureteropelvic junction disruption is a rare condition which is often diagnosed after some delay. The aim of this study is to examine the current status of this entity and to determine if improvements could be made in the diagnosis. MATERIALS AND METHODS: We evaluated 5 consecutive adult cases of ureteropelvic junction disruption secondary to blunt trauma and compared the findings to those reported in literature. RESULTS: The diagnosis was delayed by at least 24 hours in 4 of the 5 cases (80%). Compared to the literature, in which most delays in diagnosis were the result of genitourinary tract imaging being omitted, most of our delays (3 cases) were a result of the initial contrast enhanced spiral (helical) computerized tomography (CT) failing to provide the diagnosis. This failure occurred because of either absence of contrast extravasation (2 cases) or only subtle extravasation (1 case), which was not recognized by the radiologist. The delay in diagnosis resulted in added morbidity in all circumstances. CONCLUSIONS: Ureteropelvic junction disruption continues to be diagnosed late in a large proportion of cases. Absence of gross contrast extravasation on nephrogram phase scanning using spiral CT may not exclude a major injury of the ureteropelvic junction. Addition of delayed CT of the kidney 5 to 8 minutes or longer after contrast material injection (during the excretory phase) may increase the probability of extravasation being demonstrated and, thus, reduce the possibility of missing a ureteropelvic junction disruption.

Adult↗
PubMed1996

Nephrotoxicity of ioxaglate and ioversol assessed by glomerular filtration rate: a pilot study.

OBJECTIVE: To determine the effect of ioxaglate and ioversol on glomerular filtration rate (GFR) in a heterogeneous inpatient group to allow calculation of the necessary sample size for a randomized trial. PATIENTS AND METHODS: The study group consisted of 36 men and 12 women, ranging in age from 25 to 79 (mean 63) years. Fourteen of the patients, those undergoing abdominal aortography with or without renal arteriography, received ioxaglate (Hexabrix 320; 40 to 240 [mean 141] mL), and the remaining 34, those receiving intravenous injections and those undergoing computed tomography with arterioportography or carotid arteriography, received ioversol (Optiray 320; 20 to 180 [mean 87] mL). GFR was measured by determining the clearance of diethyl-enetriaminepenta-acetic acid labelled with technetium-99m up to 72 hours before and 24 hours after administration of the contrast medium. Risk factors for nephrotoxicity included diabetes (7 patients) and pre-existing renal impairment (mild in 11 and severe in 6). RESULTS: GFR decreased by 20% to 34% in six patients (13%); in only one of these was the serum level of creatinine increased at 24 hours. One of these six patients had received 120 mL of ioversol for carotid arteriography and had no risk factors for nephrotoxicity. The other five had received 40 to 187 (mean 115) mL of ioxaglate, three for abdominal aortography and two for selective renal arteriography. The risk factors in these patients included diabetes (two patients) and severe pre-existing renal impairment (two patients). Renal failure necessitating treatment did not develop in any of the patients. CONCLUSIONS: A decrease in GFR occurred more often with ioxaglate than with ioversol and usually occurred in patients with additional risk factors. Injection of contrast medium into the abdominal aorta or the renal artery may increase the risk of nephrotoxicity. Changes in serum level of creatinine at 24 hours were not reliable in identifying patients with decreased GFR. On the basis of these data, the authors estimate that a group of 194 patients would be necessary for a randomized trial comparing the nephrotoxicity of ioxaglate and ioversol for abdominal aortography.

Adult↗