Biomedical subjects

H Wallsten

Publications and source records attributed to H Wallsten.

7 recordsLinked to original sources

PubMed1990

Self-expandable stainless steel braided endoprosthesis for biliary strictures.

A new type of biliary stent was inserted in 45 patients with symptomatic biliary strictures, 40 malignant and five benign. The stent is made of stainless steel woven into a tubular mesh. It is introduced in compressed form on a 7- or 9-F delivery catheter and released at the site of the stricture. Fully open, the stent has an internal diameter of 1 cm. The 30-day mortality was 7%. The early (less than 72 hours) complication rate was 16%. Recurrent jaundice occurred in 42%; late complications of sepsis without jaundice occurred in an additional 11%. None of the stents migrated. This new design allows a large-diameter stent to be inserted percutaneously without increased risk of complications. The frequency of recurrent jaundice, however, was not less than that observed with plastic stents, but this may have reflected the spectrum of patients treated, many with hilar strictures and previous interventions.

Aged↗

PubMed1989

A new treatment for urethral strictures: a permanently implanted urethral stent.

We describe a new urethral stent, originally developed for endovascular use, that we have implanted into 8 patients with urethral strictures. The stent is woven in the form of a tubular mesh from surgical grade stainless steel wire and is self-expanding when released from its small diameter delivery catheter. All patients have been treated successfully with a good caliber urethra visible on urethrography and direct endoscopy, and with improved urine flow rates. Mean followup of these patients is 8 months (range 6 months to 1 year). Urethroscopy had demonstrated complete epithelial covering of the implant at 4 to 6 months. Although the followup is short it seems that this simple technique may offer a lasting treatment for many urethral strictures.

Adult↗

PubMed1989

A new stent for the treatment of urethral strictures. Preliminary report.

We describe a new urethral stent which was implanted into 12 patients with urethral strictures. The stent is woven in the form of a tubular mesh from fine stainless steel wire and is self-expanding when released from its small diameter delivery catheter. All patients have been treated successfully, with a good calibre urethra visible on urethrography and direct endoscopy and with improved urine flow rates. The mean follow-up of these patients was 7 months (range 2-13). Urethroscopy demonstrated complete epithelial covering of the implant in 4 to 6 months. Although the follow-up period was short, it seems that this simple technique may offer a lasting treatment for many urethral strictures. A longer follow-up will be necessary to exclude late complications.

Adult↗

PubMed1988

A new treatment for urethral strictures.

A urethral stent, originally developed for endovascular use, was implanted into eight patients with urethral strictures after experimental studies in the canine urethra. The stent is woven in the form of a tubular mesh from surgical grade stainless steel wire and is self-expanding when released from its small-diameter delivery catheter. At follow-up 6 months to 1 year postoperatively (mean 8 months) all had a good calibre urethra. Urethroscopy showed complete epithelial covering of the implant at 4-6 months.

Adult↗

PubMed1987

Self-expanding endovascular prosthesis: an experimental study.

A new type of endovascular prosthesis was inserted in 28 animals and evaluated for several factors, including thrombogenicity, tendency to migrate, critical implant zones, and incorporation into the vascular wall. The new prosthesis is a woven, multifilament structure of stainless steel alloy; its inherent elastic, self-expanding characteristics hold it against the vessel walls. Forty-seven endoprostheses (3-5 mm in diameter, 15-50 mm long) were percutaneously implanted with either a 6-F introducer sheath, a coaxial 9-F catheter, or a 0.014-inch (0.036-cm) guide wire into the femoropopliteal, coronary, carotid, and renal arteries and iliac veins. Anticoagulant or platelet antiaggregating agents were not used before or after implantation. Angiographic and histologic analyses showed that the prosthesis had a very low thrombogenicity when it was well adapted to the native vessel diameter and that it was incorporated into the vessel wall by a new intima by the 3d week after implantation. No migration occurred, and branch vessel flow was preserved even in those vessels in which ostia were traversed by the prosthesis. This prosthesis has potential for clinical application in the treatment of postangioplasty restenoses, particularly in the coronary arteries.

Animals↗

PubMedDate not supplied

Percutaneous vascular stent: experimental studies and preliminary clinical results in peripheral arterial diseases.

A new pattern of metallic intravascular stent has been experimentally and clinically tested. When the stent is percutaneously placed through a six french introducer, it is held against the vessel wall by its natural elastic properties. In 28 animals, 47 stents of different sizes (from 3 to 5 mm of luminal diameter and from 1.5 to 5 cm of length) have been implanted in the femoro-popliteal (16), the coronary (20), the carotid (3) and the renal arteries (5) and in 3 femoral veins. Angiographic and histological results have shown the stent's low thrombogenicity when it is well fit to the vessel's caliber. Moreover, they have shown its incorporation to the vessel wall by intimalisation as early as the third week after its implantation. The collateral vessels which covered by the stent remain permeable. At the end of this experimentation, 10 implants have been achieved in 8 patients (4 recurrences of iliac stenosis and 6 femoral stenosis). The angiographic results show the perfect tolerance of the organism at 6 months. This good tolerance is revealed by a thin intraluminal border which does not change the artery's diameter. This confirms the experimental results. The permeability is good except for two patients who had an obliteration after one month (one iliac and one femoral obliteration).

Angioplasty, Balloon↗

PubMedDate not supplied

The helix filter: a new vena caval filter for the prevention of pulmonary embolism.

The helix caval filter is a continuous band spiral composed of a highly elastic metal alloy. A vertical double-helix coil fixes the filter in the infrarenal vena cava by elastic expansion while a watch spring type horizontal coil works as the filtering element. The diameter of the filter can be reduced by torsion from 32 to 7 mm. Transvenous implantation was performed under fluoroscopy using a newly developed instrument featuring intraoperative angiographic control, high flexibility, a guidance system, and a well-controlled release mechanism. The filter and the implantation technique were tested in a circulation system and in 10 dogs and 4 calves (follow-up 3-91 days). In addition, two filters were released intentionally into the right atrium of a dog and a calf. Flow resistance of the filter is negligible up to more than 10 1/min. Thrombi larger than 3.5 mm were filtered out reliably. Lethal complications, filter migrations or perforations did not occur in animal experiments. Filter coils which are in contact with the vessel wall become firmly incorporated within 3 to 4 weeks. The patency rate of the vena cava was 80% (8/10) for dogs and 100% (4/4) for calves. Implantations in the right atrium did not cause any symptoms. The filter's design allows fixation without hooks or spikes and consequently makes transvenous extraction possible up to 7-10 days after implantation. Comparable clinical results could extend the indications for caval filter implantation, and the decision which is still difficult today could be made easier.

Animals↗