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Biomedical subjects

G J Becker

Publications and source records attributed to G J Becker.

At least 91 records · Page 5Linked to original sources
PubMed1992

Intravascular stents. Status of development and clinical application.

A variety of intravascular stents are currently under investigation and in various stages of achieving governmental approval for clinical application. The Palmaz balloon-expandable stent has recently been approved for use in the iliac arteries based on specific indications for application. Stents are generally described according to their method of deployment and are either balloon-expandable or self-expanding. Clinical application has been proved in the iliac arteries, where the use of stents has greatly enhanced the treatment of patients with total occlusions, complex dissections, and restenoses. Additionally, there is promise that stents will enhance the percutaneous treatment of renal artery ostial lesions, infrainguinal arterial lesions, and strictures in large veins. Clearly, the increasing application of intravascular stents has ushered in a new era of percutaneous intervention.

Arterial Occlusive Diseases↗
PubMed1992

Low-dose urokinase regimen for the treatment of lower extremity arterial and graft occlusions: experience in 132 cases.

In a retrospective review, a low-dose urokinase (UK) infusion regimen (mean, 87,000 U of UK per hour and 100 U of heparin per hour) was evaluated for lower extremity arterial and graft occlusions. Results of 132 infusions in 111 patients were analyzed to determine efficacy, limb salvage, and complications. Angiographic success was achieved with 126 infusions (95%), and amelioration of presenting signs and symptoms was achieved after 116 infusions (88%). Patients who underwent additional percutaneous procedures were more likely to have a successful outcome. There was no significant difference in success rates for patients receiving low-dose heparin through the arterial sheath (n = 101) versus those receiving concomitant systemic heparinization (n = 29), (P = .08) [corrected]. Of 88 threatened extremities (with rest pain, cold, ulcers, or gangrene), nine were amputated (limb salvage = 90%), accounting for 82% (nine of 11) of amputations in the overall study. Patients with zero- or one-vessel runoff before infusion were more likely to require limb amputation compared with the group with two- or three-vessel runoff before infusion (P less than .01). Major periprocedural complications occurred in nine of 132 (7%) infusions, five of which necessitated specific surgery and/or transfusion for bleeding. Pericatheter thrombosis was not encountered in either subgroup. This standard local low-dose infusion represents a safe and effective treatment for lower extremity arterial and graft occlusions.

Aged↗
PubMed1992

Neutralized lidocaine: use in pain reduction in local anesthesia.

The effect of pH neutralization on the pain experienced during intradermal lidocaine administration was investigated in a prospective blind study of 20 adult volunteers. A plain solution (pH congruent to 6.1) and three different buffered solutions of 1% lidocaine (pH values of 6.8, 7.0, and 7.2) were prepared, and a 0.5-mL intradermal injection of each was administered to the volar aspect of the forearm. Pain associated with lidocaine infiltration was rated with a linear visual analogue scale. Solutions with a pH of less than 6.8 (unbuffered lidocaine in this study) predictably produced a burning pain sensation on injection. However, buffering of 1% lidocaine above a pH of 6.8 significantly (P less than .05) reduced the mean quantitative pain estimates compared with the nonbuffered controls.

Adult↗
PubMed1992

Technical advances in transjugular intrahepatic portosystemic shunts.

A transjugular intrahepatic portosystemic shunt (TIPS) can be created percutaneously with the Palmaz balloon-expandable stent. This article describes a transjugular-only approach with a 16-gauge needle. A functional and efficacious shunt can be achieved in most cases with stent diameters of 8-10 mm. Occasionally, a 12-mm-diameter shunt is necessary for effective variceal decompression. The procedure is considered successful when the portosystemic gradient is lowered to 12 mm Hg or less after stent placement. Hepatic vein stenosis in the shunt outflow can develop after the TIPs procedure. This complication has been treated successfully with additional stent placement. TIPS can undoubtedly be performed successfully and safely with a transjugular-only approach; however, the full impact of TIPS on the treatment of portal hypertension remains to be determined.

Esophageal and Gastric Varices↗
PubMed1992

Preservation of renal function in chronic renal failure.

Mechanisms of progression of chronic renal failure (CRF) have been well documented in the rat but may not be relevant in man. Factors which may modify clinical CRF include underlying disease, diet, hypertension, intercurrent events, and adverse or beneficial effects of drug therapy. It has been argued that progression in many forms of renal disease is inexorable below a certain level of renal function. In other diseases, eg primary malignant hypertension, analgesic nephropathy, function frequently improves in both the short and long term with appropriate management. Thus knowledge of the nature of the underlying disease is essential in assessing progression. The value of diet in preserving renal function has been debated, particularly the relative roles of protein and phosphate control. In our own unit, a prospective randomized study showed a benefit of protein restriction. Development of accelerated hypertension is an important cause of progression of renal disease and clinical and experimental evidence supports the view that non-accelerated hypertension is also a factor in progression, amenable to treatment. Various intercurrent events may accelerate progression and function may be lost permanently following sepsis, urinary tract obstruction, renal arterial or venous obstruction, hypotension and in some cases pregnancy. Numerous drugs can have deleterious effects on the kidney. The possibility that converting enzyme inhibitors might preserve renal function is attracting attention but in view of their side effects their place in therapy should be determined by prospective controlled studies in which the above factors are carefully considered.

Animals↗
PubMed1992

Randomized study of peritonitis with conventional versus O-set techniques in continuous ambulatory peritoneal dialysis.

We performed a prospective randomized trial, comparing the incidence of peritonitis between a flush-disconnect (O-System, Baxter, Deerfield, IL) (OS) and a conventional (System II, Baxter) (CS) continuous ambulatory peritoneal dialysis (CAPD) method. Sixty consenting patients with no significant physical disabilities who commenced CAPD after May 1987 were entered and followed for a minimum of 12 months. Thirty were placed on the OS system and 30 were placed on CS. Age, gender, and time for training did not differ significantly. The period of observation for OS was 375 months; CS was observed for 430 months. OS patients experienced 28 episodes of peritonitis (13.4 months/patient/episode) compared with 88 (4.9 months/patient/episode) in CS (p less than 0.005). By 6 months, 32% of OS patients had had at least one episode of peritonitis, compared with 62% of CS patients; at 12 months, these figures rose to 48% for OS and 91% for CS (p less than 0.01) patients (Life Table Analysis). The median survival time to first peritonitis episode was 5.1 months in CS and 9.7 months in OS (p less than 0.01). Exit-site infections occurred in 14/30 (46%) of patients on OS and in 13/30 (43%) of CS patients. We conclude that the OS was associated with a significant reduction in the incidence of peritonitis.

Catheters, Indwelling↗
PubMed1991

Percutaneous transjugular portosystemic shunt.

OBJECTIVE: --To determine the effectiveness of the Palmaz balloon expandable stent for the creation of a transjugular intrahepatic portosystemic shunt. The device is designed to achieve portal decompression in patients with variceal hemorrhage secondary to portal hypertension. DESIGN: --Transjugular intrahepatic portosystemic shunting was performed in eight patients during a 9-month period. Mean follow-up was 5 months. PATIENTS: --All patients had cirrhosis with portal hypertension and varices. Bleeding occurred in seven patients from esophageal varices and in one patient from hemorrhoids. MAIN OUTCOME MEASURES: --Shunt patency and recurrent variceal hemorrhage. RESULTS: --Shunts created from a transjugular approach between a hepatic and a portal vein (diameters of 8 to 12 mm) lowered the average portosystemic pressure gradient from 36 to 11 mm Hg. Mean postoperative hospital stay was 7.7 days. Complete variceal decompression after transjugular intrahepatic portosystemic shunt placement was identified endoscopically in all eight patients. The patient treated for hemorrhoids rebled and was treated successfully by transfemoral balloon expansion of the shunt diameter from 8 to 12 mm. All shunts were patent at 1 to 9 months (mean, 5 months) of follow-up. CONCLUSION: --Initial results suggest that transjugular intrahepatic portosystemic shunt is a safe and effective method of portal decompression for the treatment of variceal hemorrhage.

Angioplasty, Balloon↗
PubMed1991

Malignant myxoid emboli as the presenting feature of primary sarcoma of the aorta (myxoid malignant fibrous histiocytoma): a case report and review of the literature.

Primary sarcomas of the aorta are rare vascular tumors. About 26 cases have been reported between 1973 and 1989. They are seldom diagnosed antemortem. The present report describes a patient with a myxoid malignant fibrous histiocytoma arising in the intima of the lower thoracic aorta, which was diagnosed premortem in metastatic peripheral emboli. The clinical and pathologic features of this patient along with a summary of the 29 primary aortic tumors previously reported (26 malignant and 3 benign) are discussed. Although few of these tumors have been described histologically as benign, all of them behave as malignant tumors.

Aged↗
PubMed1991

Early experience with the Palmaz expandable intraluminal stent in iliac artery stenosis.

Since 1987, we have used the Palmaz expandable intraluminal stent in 22 selected cases of iliac artery stenosis in 14 men and six women with a mean age of 63 years for claudication (9), graft salvage (5), rest pain (4), and tissue loss (2). Morphologic criteria included severe percutaneous balloon angioplasty-induced dissection (6), long or multiple stenoses or occlusions (5), post-percutaneous balloon angioplasty elastic recoil (4), location of stenosis (4), and restenosis following percutaneous balloon angioplasty (3). Twenty-two limbs were treated with 61 stents. The mean pressure gradient across the lesion fell from 31 +/- 15 to 1.1 +/- 2.4 mmHg after stenting. The mean ankle/brachial systolic pressure index improved from 0.59 +/- 0.31 to 0.83 +/- 0.25 after stenting. The mean follow-up is 11.4 months, with a mean ankle/brachial index at their most recent follow-up of 0.88 +/- 0.19. Symptomatically, 11 extremities are normal and five limbs are improved. Three patients have died and two have required bypass grafts for iliac occlusive disease. In this early experience, the Palmaz intraluminal stent appears to be valuable for the management of post-percutaneous balloon angioplasty restenosis, elastic recoil, and percutaneous balloon angioplasty-induced dissection, although it is not without complications.

Angioplasty, Balloon↗
PubMed1991

Standards for evaluating and reporting the results of surgical and percutaneous therapy for peripheral arterial disease.

By adopting precise definitions of essential terms, developing objective criteria by which the various measures of success or failure can be judged, and establishing a standardized scheme by which severity of disease, degrees of improvement or deterioration, and risk factors that affect outcome can be graded, the quality of published reports of revascularization procedures for lower extremity ischemia can be greatly improved, allowing comparative evaluation of treatment modalities.

Angioplasty, Balloon↗
PubMed1991

Vena caval and central venous stenoses: management with Palmaz balloon-expandable intraluminal stents.

Palmaz balloon-expandable intraluminal stents (BEISs) were used to treat vena caval and adjacent central venous obstructions that failed to respond to conventional balloon angioplasty. An initial series included seven patients: five had superior vena cava (SVC) syndrome due to a malignant neoplasm and/or radiation therapy, one had dialysis access-related stenosis of the subclavian vein, and one had inferior vena cava (IVC) and bilateral common iliac vein obstruction due to abdominopelvic radiation therapy for Hodgkin disease. Treatment produced clinical benefit in all seven patients. Patency was achieved with stents placed across stenoses of the SVC, IVC, and brachiocephalic and subclavian veins. One stent placed in a left common iliac vein was oval and was shown to be occluded on a follow-up computed tomographic scan, suggesting that compression between the right common iliac artery and the spine was responsible. Although caution is recommended in placement at possible compression sites, BEISs can be used to treat obstructions of the vena cava and major central veins.

Adult↗
PubMed1991

Percutaneous placement of a balloon-expandable intraluminal graft for life-threatening subclavian arterial hemorrhage.

A balloon-expandable intraluminal graft was percutaneously deployed in the left subclavian artery of a 43-year-old woman. This graft was made of a stainless steel, 30-mm Palmaz balloon-expandable iliac stent completely covered with a thin coat of silicone. The procedure was successful in managing and preventing life-threatening hemorrhage as a large-bore catheter was removed from the subclavian artery via its subcutaneous tunnel. Surgical repair of the high brachial-axillary sheath insertion site was required after percutaneous deployment of the graft. However, the grafting procedure succeeded in obviating a thoracotomy. At follow-up of 6 months, despite diminution in brachial pulse volume recordings, the patient is asymptomatic at rest. She experiences mild fatigue with extremes of upper extremity exercise and declines angiographic follow-up and further intervention.

Adult↗
PubMed1991

Compact contrast material bolus with a new 5-F angiographic catheter.

The conventional pigtail catheter was compared with the 5-F Tennis Racquet catheter for abdominal aortography with digital subtraction angiography. Resulting aortograms were judged on the basis of the quality of aortic opacification and renal artery visualization. The authors concluded that the Tennis Racquet catheter produces a more compact contrast material bolus, and its use is associated with acquisition of superior abdominal aortograms.

Angiography, Digital Subtraction↗
PubMed1991

Thrombin-soaked coils: estimation of thrombin dose.

Thrombin-soaked coils have been used as embolic agents for the treatment of various conditions. Intravascular injection of thrombin also has been used for thrombus formation; however, the effects of high doses of intravascular thrombin may be detrimental. In an in vitro experiment, the dose of thrombin associated with transcatheter use of thrombin-soaked steel coils was estimated. The 8 mm x 5 cm, 0.038-inch coils absorbed an overall average dose of 38.4 U (USP) of thrombin when soaked in a solution of 10,000 U of thrombin per 10 mL of saline. The same size coils absorbed an overall average dose of 71.6 U of thrombin when soaked in a concentration of 20,000 U of thrombin per 10 mL of solution. Maximum single-coil absorbed doses were 45.6 and 88.2 U for 1,000 and 2,000 U/mL, respectively. A plateau in thrombin absorption occurred after 1 minute of soaking. Absorption of thrombin was maximized by soaking the coils in a vertical orientation; almost no thrombin was absorbed when the coils were soaked in a horizontal position.

Embolization, Therapeutic↗