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Biomedical subjects

D W Hunter

Publications and source records attributed to D W Hunter.

At least 163 records · Page 9Linked to original sources

Carbon dioxide as a lighter-than-urine contrast medium for percutaneous nephrostomy.

Carbon dioxide was used either alone or in combination with standard triiodinated contrast media in 32 patients who underwent percutaneous nephrostomy. Carbon dioxide was used to opacify the posterior calyces, which are the uppermost structures in the kidney of the prone or prone-oblique patient. Carbon dioxide is usually injected in small amounts (20-40 cm3), although clinical and laboratory data indicate that it can be used as the only medium in large amounts with complete safety. There were no complications.

Adult↗

A new vena caval filter for percutaneous placement and retrieval: experimental study.

A new vena caval filter that can be inserted percutaneously through an angiographic catheter is described. The filter is secured by controlled penetration of the caval wall and is designed for percutaneous retrieval. The filter was easily and safely placed and removed in 11 mongrel dogs, and in an in vitro study, the filter was shown to be highly effective and less dependent than the Greenfield filter on positioning. The authors believe that the filter will be suitable for prophylactic placement in patients at high risk for pulmonary thromboembolic disease.

Animals↗

Failing arteriovenous dialysis fistulas: evaluation and treatment.

A total of 31 patients with 45 episodes of failing arteriovenous dialysis fistulas was studied. Fistula failure was usually due to venous and/or anastomotic stenosis, often in conjunction with thrombosis. Abnormalities were treated by percutaneous dilation and occasionally streptokinase infusion. Most complications and failures occurred either in patients with recently created fistulas or in those with multiple or long segment stenosis associated with thrombosis. Patients with a single nonobstructing stenosis were very successfully treated with percutaneous techniques, which are the treatment of choice for this condition.

Adult↗

A logical approach to renal stone removal.

On the basis of experience with over 350 percutaneous stone extractions, a logical approach assuring a high success rate and minimizing complications is described. The importance of the position of the kidney in the body, the caliceal anatomy, the renal arterial anatomy, and the instrumentation used on puncture site selection are discussed. Strategies for removal of caliceal, pelvic, ureteral, and staghorn calculi, rationale, and treatment of complications are also described.

Humans↗

Rapid balloon dilatation of the nephrostomy track for nephrostolithotomy.

The Olbert balloon catheter can be used to dilate a nephrostomy track from 9 to 30 F (3 to 10 mm) in a single step. Percutaneous nephrostomy, track dilatation, and percutaneous stone extraction can be performed within 40 to 90 minutes. The authors have used this catheter successfully in 10 patients without encountering complications.

Catheterization↗

Percutaneous techniques in the management of urological complications in renal transplant patients.

Obstruction of urine flow and urine leaks are potentially life-threatening complications in renal transplant patients. The diagnosis is difficult, and definite treatment may therefore be delayed. This paper reviews the clinical course of ten renal transplant patients with urologic complications, discusses the limitations of the standard tests used to investigate such problems, and describes the role of percutaneous antegrade pyelography and nephrostomy drainage catheter placement as safe and accurate diagnostic and therapeutic procedures.

Adolescent↗

Failing or thrombosed Brescia-Cimino arteriovenous dialysis fistulas. Angiographic evaluation and percutaneous transluminal angioplasty.

Surgically created arteriovenous fistulas of the Brescia-Cimino type are commonly used for dialysis. When they fail, it can be a very difficult and time-consuming problem to manage surgically. The authors describe a simple method of evaluating and treating failing Brescia-Cimino fistulas in outpatients, involving a combination of cinefistulography, pressure measurements, and balloon angioplasty.

Adult↗

Malignant facial tumors in children: radiologic evaluation. Stressing value of conventional and computerized tomography.

Twenty-five cases of malignant tumors of the face in children under 16 years of age were reviewed. In each case the presenting complaint was related to a mass of the face, without a known primary malignancy. Rhabdomyosarcoma was the most common malignancy, followed by equal numbers of histiocystic malignancies and malignant lymphomas. Chloroma and neuroblastoma were less common. Plain films were obtained on every patient and were always felt to be an appropriate part of the work-up. The plain films suggested or made the diagnosis of malignancy in 16 of the patients. The most helpful additional study was tomography. CT was the modality of choice for tumors originating in or extending into the orbit, and for intracranial extension. Xeroradiography best demonstrated a superficial soft tissue tumor. In evaluating facial malignancies, the number and sequence of examinations must be individualized according to the presentation.

Adolescent↗

The biocompatibility of compressed collagen foam plugs.

The tissue reaction to reexpanded, purified bovine collagen sponge placed percutaneously into the lung, pleural space, liver, kidney, and muscle was studied in dogs and rabbits. In addition, the biocompatibility and radiopacity of tantalum-treated collagen foam plugs was examined. No adverse effects were found. We believe that collagen plugs may be of use in occluding needle tracts from biopsy sites to prevent complications such as bleeding or pneumothoraces.

Animals↗

The incidence of myocardial bridges in heart transplants.

Coronary angiograms of 64 heart transplant patients were reviewed to determine the incidence of myocardial bridges. In 33% of the patients, myocardial bridges were detected, almost exclusively across the midportion of the left anterior descending coronary artery. The incidence is higher than previously reported in the literature and is thought to be related to increased stiffness and hypertrophy of the myocardium, which facilitates angiographic detection of myocardial bridges in the transplanted heart.

Adult↗

Reversible hepatic transplant ischemia: case report and review of literature.

We report the successful treatment of a hepatic arterial anastomotic stenosis by angioplasty in an orthotopic liver transplant recipient. The patient had already undergone hepatic infarction and compromised allograft function and sepsis. Baseline duplex ultrasound and angiographic studies showed obstruction of the transplant arterial anastomosis. Following angioplasty, allograft function, areas of infarction, and duplex ultrasound studies returned to normal. At 6-month follow-up the patient remains asymptomatic.

Adolescent↗

Venous recanalization by metallic stents after failure of balloon angioplasty or surgery: four-year experience.

PURPOSE: This retrospective study describes our updated experience in treating venous stenoses and occlusions with metallic endovascular stents. METHODS: Gianturco, Palmaz, and Wallstent stents were placed in 55 patients over a 4-year period. Stent sites included the subclavian veins (9), innominate veins (3), superior vena cava (4), inferior vena cava (3), iliac veins (29), femoral veins (5), and portal veins (6). The most common indications for stent placement were malignant stenoses and chronic pelvic venous occlusions. Venoplasty and/or urokinase were used as ancillary therapy. Patients were anticoagulated for 3-6 months. Follow-up included clinical assessment and duplex ultrasound. RESULTS: Lifetable analysis shows 59%, 63%, and 72% primary, primary assisted, and secondary 1-year patency rates, respectively. The 4-year primary patency rates were the same. Duration of patency depended on the venous site. Death was a complication of stent placement in 2 patients and 12 patients died within 6 months after stent placement from primary disease progression. Although early failures were more common in stents placed across occlusions than stenoses, 1-year secondary patency rates were comparable. Primary patency rates were only slightly lower in patients with malignant obstruction than in patients with benign disease. CONCLUSION: Endovascular stent placement provides a nonsurgical alternative for reestablishment of venous flow and symptomatic relief in patients with benign as well as malignant venous obstruction.

Angioplasty, Balloon↗

A stepless needle-dilator for expedient percutaneous catheterization: technical note.

A new stepless needle-dilator is described which allows arterial puncture and dilation in a single step using a single wall puncture technique. The new needle-dilator causes significantly less arterial damage than a conventional dilator (p less than 0.05). Additionally, time and cost savings are realized by clinical users.

Angiography↗

Early sonographic evaluation of the transjugular intrahepatic portosystemic shunt (TIPS).

The purpose of this study was to evaluate duplex and color Doppler findings in patients before and within 24 h after transjugular intrahepatic portosystemic shunts (TIPS). Conventional duplex and color Doppler were used in the assessment of 19 patients who underwent TIPS as part of a prospective protocol. Patients were examined within 24 h before and after the procedure. Before TIPS, patency, flow direction, and peak flow velocity in the main portal vein and hepatic artery were studied, as well as patency and flow direction in hepatic veins, splenic vein, and inferior vena cava (IVC). Immediately after the procedure, sonographic identification of stent position, shunt patency, and flow dynamics were evaluated and patency and flow direction of hepatic veins, splenic vein, and IVC were determined. The portogram performed at the end of the procedure was compared with the 24-h sonographic studies after TIPS to determine sonographic/angiographic correlation. No intraparenchymal abnormalities or perihepatic fluid collections were detected after the procedure. The metallic stent was clearly seen in all patients. Mean peak shunt flow velocities were 139 +/- 50 cm/sec within 24 h after TIPS. Absence of flow through the shunt was correctly identified in one case and confirmed angiographically. Mean peak flow velocity in the portal vein before TIPS was 22 +/- 13.6 cm/sec and increased to 43.6 +/- 9.1 cm/sec after TIPS (p < 0.05). The hepatic artery peak systolic velocity increased from 77 +/- 51 cm/sec before TIPS to 119 +/- 53 cm/sec after the procedure (p = 0.029).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Flow Velocity↗

Dialysis grafts arterial plug: retrieval using the tulip sheath device in vitro.

The "arterial plug" is a resistant thrombus that frequently persists at the arterial anastomosis of clotted hemodialysis grafts following thrombolytic therapy. We studied the physical and morphological characteristics of the plug and determined the feasibility of transcatheter removal in vitro using the tulip compression thrombectomy system. Sixteen thrombus plugs were recovered during surgical thrombectomy of clotted human dialysis grafts. The physical and gross physical characteristics of all plugs were analyzed. Eight specimens were evaluated microscopically. Transcatheter compression thrombectomy of eight plugs was attempted in vitro. Each plug was embedded in a polyvinyl tube filled with newly clotted blood and connected to a flow circuit. First, balloon-assisted aspiration thrombectomy (BAT) of soft thrombus was performed, while sparing the distal-most segment containing the plug. The tulip sheath was then introduced facing the "arterial end" of the tube. The thrombus segment containing the plug was pulled back into the tulip mesh using either a 3 Fr Fogarty balloon catheter or a self-expanding rake. The tulip was closed to compress and remove the trapped plug. Near-complete thrombectomy of soft clot was achieved in all tested tubes. Compression and retrieval of the entire arterial plug was successful in all except one, where only partial compression of the plug occurred, presumably due to fibrotic changes. No fragmentation or embolization occurred in the remaining procedures. Spongy consistency was noted in 94% of the specimens. Microscopic evaluation showed organized layered thrombus with compaction in five plugs. Transcatheter removal of a thrombus plug is feasible in vitro using the tulip compression-thrombectomy system.

Arteriovenous Shunt, Surgical↗