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Biomedical subjects

P Ortenwall

Publications and source records attributed to P Ortenwall.

18 recordsLinked to original sources
PubMed1995

Effects of spinal cord stimulation (SCS) in patients with inoperable severe lower limb ischaemia: a prospective randomised controlled study.

OBJECTIVES: This study was designed to test the hypothesis that spinal cord stimulation (SCS) improves limb salvage in patients with inoperable severe leg ischaemia. DESIGN: Prospective randomised controlled study with 18 months follow-up. SETTING: Vascular surgical units in two university hospitals. MATERIALS: Atherosclerotic (n = 41) and diabetic (n = 10) patients having chronic leg ischaemia with rest pain and/or ischaemic ulcerations due to technically inoperable arterial occlusions. CHIEF OUTCOME MEASURES: Limb salvage and amount of tissue loss within 18 months, pain relief. MAIN RESULTS: Twenty-five patients were randomized to SCS and 26 to analgesic (control) treatment. Macrocirculatory parameters were not different in the two groups during follow-up. Long-term pain relief was observed only in the SCS group. At 18 months, limb salvage rates in the SCS and control groups were 62% and 45% (N.S.). Tissue loss was less (p = 0.05) in the SCS group. A subgroup analysis of patients without arterial hypertension showed a significantly lower amputation rate in the SCS vs the control group. CONCLUSIONS: SCS provided long-term pain relief but limb salvage at 18 months was not significantly improved by SCS in this rather small study. The results suggest that SCS may reduce amputation levels in patients with severe inoperable leg ischaemia and be most effective in patients without arterial hypertension.

Aged↗
PubMed1992

Age-standardized incidence of ruptured aortic aneurysm in a defined Swedish population between 1952 and 1988: mortality rate and operative results.

The incidence and mortality rate of ruptured aortic aneurysm in a defined and stable Swedish population was determined for the period 1952-1988. The annual rupture rate of abdominal aneurysm rose significantly from 0.9 per 100,000 inhabitants in the 1950s to 6.9 in the 1980s. After standardization for age, the mortality rate increased between 1960 and 1988 by 2.4 per cent annually (95 per cent confidence interval 1.2-3.6 per cent, P = 0.0004). Comparable figures from the UK during the 1980s have been reported to be two to three times higher. The mortality rate of ruptured thoracic aneurysm in the Swedish population did not increase when adjusted for age. In the 1980s the overall mortality rate of ruptured abdominal aneurysm was 85 per cent. Death occurred outside surgical clinics in 52 per cent of cases; 37 per cent of the total number of patients with ruptured aneurysm reached the operating table but only 30 per cent underwent aortic reconstruction. Patients treated by vascular surgeons had lower blood loss and transfusion needs, shorter aortic clamp time and operation time, and lower mortality rate than patients treated by non-specialized general surgeons. Specialized vascular surgeons also completed the reconstruction, and used straight grafts, in a higher proportion of cases than general surgeons.

Age Factors↗
PubMed1992

Combined angioplasty with the Kensey catheter and balloon angioplasty in occlusive arterial disease. A preliminary report.

The Kensey dynamic angioplasty catheter is an instrument for mechanical intravascular atherectomy using a rotating cam to recanalize occluded arteries. Twelve dynamic angioplasties were performed in 11 patients. The procedure was followed by an additional balloon dilatation in all cases. A technical success, i.e., a restored lumen, was recorded in 7 patients but only 4 had a functional improvement. No distal embolization or other serious complication occurred. This preliminary report shows that the therapeutic potential with this technique must be further investigated.

Adult↗
PubMed1991

Oxygen radicals and lung injury.

This article describes the formation of oxygen radicals and their biological effects, especially in relation to lung injury. Various recent experimental data are reviewed. The relationships between hydrostatic effects and permeability effects in producing injury and edema are stressed. Means of prevention and problems related to extrapolation to clinical situations are focused.

Animals↗
PubMed1990

Venous endoscopy in thrombectomy of the iliac veins using the choledochoscope.

In the present communication venoscopy using a flexible choledochoscope is advocated after thrombectomy of the iliac veins. In 10 patients operated upon for occlusive thrombi in the pelvic veins, venoscopy was used to assess the status of the vein. The procedure was conveniently performed using a regular flexible choledochoscope. Venoscopy gave detailed information of the veins and lead to altered therapy in seven of the 10 patients. Venoscopy is recommended for intra-operative control during surgical thrombectomy and the use of a choledochoscope can simplify this procedure.

Endoscopes↗
PubMed1990

Endothelial cell seeding reduces thrombogenicity of Dacron grafts in humans.

Vascular prostheses in humans do not endothelialize spontaneously. In the present study we explored the feasibility of seeding autologous endothelial cells into prostheses implanted in patients undergoing reconstruction of the infrarenal aorta. In 22 patients one limb of an aortic Dacron bifurcation prosthesis was seeded with autologous endothelial cells harvested from the distal portion of the saphenous vein. The other limb was sham-seeded with culture medium only. The effect of seeding was studied by use of indium 111 radiolabeled platelets and external gamma camera scanning at 1, 4, and 12 months after surgery. No complications ascribable to the seeding procedure were seen. During the first year after surgery a gradual decrease in platelet accumulation occurred over the whole vascular prosthesis. At all time points studied the seeded graft limbs exhibited significantly less deposition of radiolabeled platelets than did control limbs. The observed difference in platelet accumulation on autologous endothelial seeding-treated graft segments merits further investigation of this technique in humans.

Aged↗
PubMed1989

A new incision for retroperitoneal approach to the aorta.

A new incision for retroperitoneal approach to the abdominal aorta is described. The incision extends from alongside the rectus abdominis muscle across the costal arch over the 7-8th intercostal space. In the upper part only the skin and muscles are divided, allowing wide opening of the incision. The approach is muscle-sparing, since fibers of the transverse abdominal muscle are incised only in the upper part. It permits a good approach even for high aortic reconstruction.

Aorta, Abdominal↗
PubMed1989

Reduced platelet deposition on seeded versus unseeded segments of expanded polytetrafluoroethylene grafts: clinical observations after a 6-month follow-up.

The concept of autologous endothelial cell seeding has proved successful in animal models with respect to decrease of graft thrombogenicity and increase in patency. In the present study, application of this method in humans was explored. In 23 patients, random halves of expanded polytetrafluoroethylene grafts, used for lower limb arterial reconstructions, were seeded with endothelial cells at a seeding density of 3500 cells/cm2. These cells were derived from the saphenous vein by enzymatic harvesting. The other half was sham seeded with culture medium. Graft thrombogenicity was estimated by measuring platelet deposition on graft surface 1 and 6 months after surgery, with indium 111-labeled platelets and external gamma-camera imaging. Seeded graft segments accumulated significantly (p less than 0.03) fewer platelets at all imaging times. It is concluded that seeding of expanded polytetrafluoroethylene vascular grafts in humans reduces graft surface thrombogenicity. The clinical implications of this remain to be demonstrated.

Aged↗
PubMed1988

Splenic platelet kinetics and platelet production after major reconstructive vascular surgery.

By using 111In-labelled platelets and dynamic gamma camera scintigraphy, platelet production rate and intrasplenic platelet kinetics were determined in 13 patients at 1 and 4 months after aortic reconstructive vascular surgery with implantation of dacron prostheses. A significant decrease in platelet production rate and venous platelet count was recorded over time after surgery. Irrespective of whether the exchangeable splenic platelet pool was estimated from initial recovery of platelet-bound radioactivity or from compartmental analysis, the size of this pool was significantly lower at the first study; a change in intrasplenic platelet transit time accounted for the observed difference. Platelet mean life-span increased over time after surgery but the difference between the duplicate studies was not statistically significant. It can be concluded that there is a reduction of platelet production rate and venous platelet count over time after major reconstructive vascular surgery. The early postoperative elevation in the platelet count is mainly the result of an increased platelet production and to a lesser degree due to redistribution of platelets between the splenic platelet pool and general circulation.

Aged↗
PubMed1988

Seeding of ePTFE carotid interposition grafts in sheep and dogs: species-dependent results.

Autologous endothelial seeding of thin-walled ePTFE vascular prostheses (I.D.4 mm), interposed in the carotid artery, was performed in 10 dogs and 14 sheeps. Aspirin (250 mg/day) and dipyridamole (75 mg/twice daily) were given throughout the study as antiplatelet therapy. Animals were killed 2 and 5 weeks after surgery. Patency rates for seeded grafts in dogs were 75% (6:8) and 83% (10:12) at 2 and 5 weeks, respectively. In control grafts the patency rates were identical. Patency rates for seeded grafts in sheep were 0% (0:5) and 11% (1:9) at 2 and 5 weeks, respectively. Control grafts in sheep had a patency rate of 40% (2:5) and 0% (0:9) at corresponding times. Scanning electron microscopy showed an almost complete endothelialization of seeded grafts in dogs after 5 weeks. Platelet deposition was studied in the dogs by means of chromium-51-labeled autologous platelets. Significantly fewer platelets accumulated on seeded grafts, and the ratio of 6-keto-PCF1 alpha to thromboxane B2 was significantly higher, compared with unseeded grafts, which indicated the presence of a functionally active endothelial lining in seeded grafts. Differences in the hemostatic system could account for the high clotting incidence in sheep, compared with that in dogs. Such species differences make extrapolations to the clinical situation from autologous endothelial seeding in experimental animals hazardous.

Animals↗
PubMed1987

Comparison of oxidative metabolism in vitro in endothelial cells from different species and vessels.

Oxygen consumption was compared in confluent cultures of endothelial cells from human umbilical cord veins, rat pulmonary arteries, and bovine aortas. A microrespirometric method utilizing oxygenated hemoglobin as oxygen supply and indicator of respiration was used. Respiratory rate was equal in human and murine cells (2.0 X 10(-6) and 2.2 X 10(-6) microliters O2/cell/hour respectively), compared on a cell-to-cell basis, while respiratory rate of the bovine endothelium was significantly lower (0.4 X 10(-6) microliters O2/cell/hour) (P less than .001).

Animals↗
PubMed1987

Reduction in deposition of indium 111-labeled platelets after autologous endothelial cell seeding of Dacron aortic bifurcation grafts in humans: a preliminary report.

Autologous endothelial seeding (AES) of vascular prostheses in dogs increases thrombus-free surface and improves prosthetic prostacyclin production, patency, and the ability to withstand hematogenous challenge with bacteria. No such information is available in human subjects. In the present study one limb of an aortic Dacron bifurcation prosthesis was seeded with autologous endothelial cells (ECs) harvested from the distal portion of the saphenous vein by enzymatic treatment. The deposition of indium 111-labeled platelets on the vascular prostheses was studied 1 and 4 months after operation. In seven of nine patients seeding resulted in decreased accumulation of radiolabeled platelets compared with sham-seeded control limbs (p less than 0.04), when studied 1 month after surgery. A decrease in platelet accumulation occurred over the whole prosthesis between 1 and 4 months, and no significant difference was noted at 4 months between seeded and nonseeded graft limbs. Although the seeding density was very low (440 ECs/cm2), the observed difference in platelet accumulation for AES-treated graft limbs in the early postoperative course merits further investigation of this technique in human beings.

Aged↗
PubMed1987

Prognostic value of consecutive peripheral pressure registration after reconstructive peripheral arterial surgery.

A reliable predictive test as a guide in selection for arterial reconstruction vs. primary amputation would be of great value. An ideal test should also be simple and noninvasive. We evaluated prediction based on preoperative and early postoperative (repeatedly in the first week) measurements of ankle and toe pressure in relation to patency 6 months after reconstructive peripheral vascular surgery in 39 patients. Occlusion occurred within 6 months in ten patients. In eight of them the preoperative ankle-brachial pressure index (ABI) was less than 0.4, but seven other patients with ABI less than 0.4 had maintained patency. In six of the ten with occlusion the toe-brachial pressure index (TBI) was less than 0.1, but in three others with TBI less than 0.1 the grafts were patent. During the first postoperative week there was progressive rise in pressure indices, reaching statistical significance on day 6, though with greatest rise on day 1. Although preoperative ABI less than 0.4 and TBI less than 0.1 were associated with high occlusion risk, the specificity of these indices was too low for predictive value. The repeated measurements during postoperative week 1 added no useful information to that obtained on day 1.

Aged↗
PubMed1985

Effects of 5-hydroxytryptamine and related agents on endothelial cell oxidative metabolism in vitro.

A recently described microrespirometric method was used to determine the influence of 5-hydroxytryptamine (5-HT), nialamide, imipramine and ouabain alone and in combinations on oxidative metabolism in monolayer cultures of endothelial cells from the rat pulmonary artery. It was found that exposure to 5-HT increased oxygen uptake in the cultures, while imipramine or ouabain decreased respiration; nialamide had no obvious effect. When used in combinations, the effect of ouabain or imipramine dominated over the 5-HT effect. The explanation for this 5-HT stimulating effect on endothelial cell oxidative metabolism, previously undescribed, is suggested to be that 5-HT exposure stimulated individual cells to contract. This active contraction resulted in an increased energy demand reflected in elevated oxygen consumption, an effect inhibited by ouabain or imipramine.

Animals↗