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A Lundell

Publications and source records attributed to A Lundell.

At least 19 recordsLinked to original sources
PubMed2001

[Ruptured abdominal aortic aneurysm. Endovascular treatment under local anesthesia].

We report on endovascular repair of a ruptured abdominal aortic aneurysm. A bifurcated stent graft was inserted under local anesthesia. Aortic clamping is rapidly provided by percutaneous placement of an aortic occlusion balloon catheter. Carbon dioxide can usually replace conventional contrast in patients with renal insufficiency. This minimally invasive procedure may reduce perioperative morbidity and mortality in patients with ruptured aortic aneurysms. The advantages and limitations of this novel technique are discussed.

Aged↗
PubMed1999

Reduction in vascular lesion formation by hirudin secreted from retrovirus-transduced confluent endothelial cells on vascular grafts in baboons.

BACKGROUND: The hypothesis that thrombin mediates the formation of neointimal vascular lesions at sites of mechanical vascular injury has been tested in baboons by measurement of the effects of hirudin delivered by retrovirus-transduced hirudin-secreting vascular endothelial cells (ECs) lining surgically implanted arterial vascular grafts (AVGs). METHODS AND RESULTS: The antithrombotic efficacy of baboon ECs transduced with cDNA encoding hirudin was assessed in vitro and in vivo on thrombogenic segments in chronically exteriorized femoral arteriovenous (AV) shunts. Bilateral brachial AVGs lined with hirudin-transduced versus nonhirudin control ECs at confluent density were surgically implanted, and vascular lesion formations at distal graft-vessel anastomoses were compared after 30 days. Hirudin-transduced ECs secreted 20+/-6 ng x 10(6) cells(-1) x 24 h(-1) (range, 14 to 24 ng x 10(6) cells(-1) x 24 h(-1)) hirudin in supernatants of static cultures. Hirudin-secreting ECs on segments of collagen-coated graft interposed in chronic AV shunts decreased the accumulation of (111)In-labeled platelets to 0.52+/-0.34 x 10(9) platelets, compared with 0.82+/-0.49 x 10(9) platelets in controls (P = 0.03) and reduced platelet deposition in propagated thrombotic tails extending downstream from segments of vascular graft from 1.38+/-0.41 x 10(9) platelets in controls to 0.59+/-0.22 x 10(9) platelets (P = 0.04). ECs recovered from 30-day AVG implants generated 17+/-9 ng x 10(6) cells(-1) x 24 h(-1) (range, 9 to 25 ng x 10(6) cells(-1) x 24 h(-1)) hirudin. Hirudin-secreting ECs reduced neointimal lesion formation at distal graft-vessel anastomoses, ie, 1.02 mm(2) (range, 0.88 to 1.95 mm(2)) versus 1.82 mm(2) (range, 0.88 to 2.56 mm(2)) in contralateral AVGs bearing nonhirudin control ECs (P<0.01). CONCLUSIONS: Viral vector-directed secretion of hirudin from ECs lining implanted AVGs significantly reduces the formation of thrombus and neointimal vascular lesions.

Animals↗
PubMed1999

Do residual arteriovenous fistulae after in situ saphenous vein bypass grafting influence patency?

PURPOSE: The purpose of this study was to evaluate the influence on patency of residual arteriovenous fistulae (AVF) after in situ saphenous vein bypass grafting. METHODS: Between January 1, 1994, and December 31, 1996, 98 in situ saphenous vein bypass grafting procedures were performed in 94 patients. Patency was evaluated with duplex scanning after operation and at 1, 3, 6, 9, and 12 months. RESULTS: The indications for operation were intermittent claudication in two patients and critical leg ischemia in 92 patients. Two above-knee and 48 below-knee femoropopliteal and 48 femorocrural in situ saphenous vein bypass grafting procedures were performed. The median follow-up period was 9 months (range, 1.5 to 12.5 months). There were no residual AVF in 45 veins (44%; group 1), but 110 residual AVF were found in 53 veins (56%; group 2). In group 2, 36 AVF in 18 veins were surgically or radiologically occluded mainly as a result of a flow velocity decrease distal to the AVF, but the remaining 74 AVF were treated conservatively. The 1-year cumulative primary patency rates were 68% in group 1 and 74% in group 2 (log-rank test, 0.47; degree of freedom = 1; P =.52). The 1-year cumulative assisted primary patency rates were 68% in group 1 and 81% in group 2 (log-rank test, 2.19; degree of freedom = 1; P =. 14). CONCLUSION: Residual AVF after in situ bypass grafting without influence on bypass graft hemodynamics do not compromise patency and thrombose spontaneously.

Aged↗
PubMed1999

Graft surveillance.

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Blood Vessel Prosthesis↗
PubMed1996

Localizing antithrombotic and vasodilatory activity with a novel, ultrafast nitric oxide donor.

Reaction of nitric oxide (NO) with L-proline in methanolic sodium methoxide yields a diazeniumdiolate product, C5H7N3O4Na2.CH3OH (PROLI/NO), that can be stabilized in basic solution but that dissociates to proline (1 mol) and NO (2 mol) with a half-life of only 1.8 s at pH 7.4 and 37 degrees C. This kinetic behavior has allowed the generation of highly localized antiplatelet and vasodilatory effects. By infusing solutions containing 4 microM PROLI/NO in 0.1 M sodium hydroxide at the rate of 1 nmol.min-1 immediately upstream from a polyester vascular graft in the unheparinized baboon circulatory system, for example, platelet deposition at the normally thrombogenic graft surface was substantially reduced relative to controls receiving only 0.1 M sodium hydroxide. In a second study, infusion of PROLI/NO into the right atrium of sheep with induced pulmonary hypertension selectively dilalated the lung vasculature, dose-dependently reducing the pulmonary arterial pressure by as much as 9 mmHg with no observable effect on the systemic arterial pressure at an infusion rate of up to 24 nmol.kg-1.min-1. PROLI/NO could also be formulated as an insoluble polymer blend that released NO smoothly for prolonged periods. The results suggest that localized delivery of diazeniumdiolates such as PROLI/NO which generate NO with extreme rapidity on entering the blood stream may hold considerable promise for inhibition of thrombus formation, selective dilation of the vasculature, and other research and clinical applications.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1996

Impaired renal artery blood flow at transplantation is correlated to delayed onset of graft function.

The aim of this prospective study was to evaluate a transit time flowmeter (Transonic, USA) in renal transplantation with respect to feasibility and estimation of graft circulation. Subsequently, the measurements were evaluated for their ability to predict delayed onset of function, occurrence of acute rejection or graft loss within 3 months after transplantation. Renal artery blood flow was measured and resistance calculated in 100 transplants-62 cadaveric donor (CD) and 38 living donor (LD)-immediately after restoration of graft circulation and before wound closure. Low blood flow (< 250 ml/min) and high resistance (> 392 mPRU) correlated positively with a long cold ischemia time and delayed onset of graft function, including the need for post-transplant dialysis. No correlation with rejection or graft loss was found. Blood flow measurements with the transit time flowmeter were easy to perform and immediate estimation of transplant circulation was achieved. Transplants at risk for delayed onset of function were identified.

Adult↗
PubMed1995

Femoropopliteal-crural graft patency is improved by an intensive surveillance program: a prospective randomized study.

PURPOSE: The purpose of this study was to evaluate whether intensive surveillance compared with routine follow-up examinations improves femoropopliteal/crural graft patency. METHODS: After operation the patients were randomized to intensive (n = 79) or routine surveillance (n = 77). The groups were matched with regard to sex, diabetes, indication for surgical procedure, surgical procedure, and graft material. Intensive surveillance was clinical examination, ankle/brachial index measurements, and duplex scans 1, 3, 6, 9, 12, 15, 18, 21, 24, and 36 months after operation. Routine surveillance was clinical examination and ankle/brachial index measurements without duplex scanning 1, 12, 24, and 36 months after operation. Grafts with a decrease in ankle/brachial index of more than 0.15 compared with the initial postoperative ankle/brachial index or a duplex scan showing a graft or anastomotic stenosis of more than 50% underwent angiography and if necessary, a revision or repeat procedure. Occluded grafts were reopened with thrombectomy or thrombolysis or were replaced with a new graft. RESULTS: Assisted primary cumulative vein graft patency in the intensive group (n = 56) compared with that in the routine surveillance group (n = 50) after 3 years was 78% versus 53% (chi square analysis, 4.51; one degree of freedom; p < 0.05). Secondary patency was 82% versus 56% (chi square analysis, 5.62; one degree of freedom; p < 0.05). Assisted primary cumulative e-polytetrafluoroethylene and composite graft patency after 1 year in the intensive group (n = 23) compared with that of the routine surveillance group (n = 20) was 57% vs 50% (chi square analysis, 2.17; one degree of freedom; p > 0.1). Secondary patency was 67% vs 54% (chi square analysis, 1.85; one degree of freedom; p > 0.1). Revisions were made on 14 patent and 10 thrombosed grafts in the intensive group and on four patent and 15 thrombosed grafts in the routine surveillance group. All except eight were made during the first postoperative year. CONCLUSIONS: Intensive surveillance identified failing vein grafts leading to a significantly higher cumulative assisted primary and secondary patency compared with cumulative assisted primary and secondary patency after routine follow-up examination. The patency of e-polytetrafluoroethylene and composite grafts was not influenced by intensive surveillance.

Aged↗
PubMed1995

Effect of dextran and enoxaparin on early ePTFE graft thrombogenicity in sheep.

OBJECTIVES: To evaluate the effect of low molecular weight heparin (LMWH), dextran 70 and their combination on platelet adhesion and fibrinogen uptake in ePTFE grafts in an experimental sheep model. DESIGN: Prospective open study. SETTING: Animal Laboratory of a University Hospital. MATERIALS: Early thrombogenicity of ePTFE grafts was studied after interposition in the two common carotid arteries of 40 adult sheep. The animals received one of four different treatment regimens in a double blind randomised way: enoxaparin and polygeline, saline and dextran 70, enoxaparin and dextran 70 or saline and polygeline (control). The substances were administered i.v. with a total dose of 73 antifactor-Xa U/kg for enoxaparin and 1.0 g/kg for dextran 70. Polygeline and saline were used as placebo substances in equivalent volumes. On one side (random allocation) the carotid blood flow was restricted to 25 ml/min, on the other side it was left unrestricted. CHIEF OUTCOME MEASURES: The following variables were studied: 1) fibrinogen uptake; 2) platelet uptake; 3) early graft patency; 4) blood flow in patient grafts; 5) visible presence of graft thrombus; 6) thrombus weight. MAIN RESULTS: The results verified the importance of adequate blood flow as only 30% of grafts with restricted blood flow in the control group were patent compared with 80% of those with unrestricted blood flow (p = 0.038). Dextran 70, enoxaparin and the combination of the two increased early graft patency (p < 0.05) and reduced thrombus weights (p < 0.05) in grafts with restricted blood flow. The relative number of grafts with thrombus free surface was increased in the unrestricted blood flow situation. CONCLUSIONS: Dextran 70 and enoxaparin appeared to be equally effective in decreasing fibrinogen and platelet uptake in the grafts. Their combination was not significantly more effective although there was a favourable trend.

Animals↗
PubMed1993

The uptake of platelets, fibrinogen and leucocytes in ePTFE vascular grafts in relation to blood flow--an experimental study in sheep.

The uptake of platelets, fibrinogen and leucocytes in relation to blood flow was studied in ePTFE arterial grafts inserted in both common carotid arteries of 10 adult sheep. Autologous platelets labelled with In-111, autologous leucocytes labelled with Tc-99m and homologous fibrinogen labelled with I-125 were used. The leucocyte uptake was studied in five of the animals. The uptake was measured with a gamma scintillation technique. The blood flow in the graft on one side was restricted to 25 ml/mm, and in the other graft the blood flow was unrestricted (median 170 ml/min). One out of 10 grafts in the reduced flow group occluded but none of the grafts in the unrestricted flow group. The mean thrombus weight was significantly higher in the reduced unrestricted flow (0.28 vs. 0.19 g). At the proximal anastomosis the uptake of platelets, fibrinogen and leucocytes was higher in the reduced than unrestricted flow. The differences were significantly higher for fibrinogen for the whole duration of the experiments and for platelets and leucocytes during the last 48 min. Distally the platelet and fibrinogen uptake were higher in the reduced than in unrestricted flow. The leucocyte uptake did not differ distally. The differences were significant for fibrinogen for the whole duration of the experiments and for platelets during the last 120 min. A comparison between the proximal and distal anastomosis showed a higher uptake distally.

Animals↗
PubMed1993

Prediction of early graft occlusion in femoropopliteal and femorodistal reconstruction by measurement of volume flow with a transit time flowmeter and calculation of peripheral resistance.

A transit time flowmeter (Transonic TC101DTM, Transonic Inc., U.S.A.) was used for flow measurements and calculation of peripheral resistance in 48 primary femoropopliteal and femorodistal reconstructions. The results were correlated with primary graft occlusions during the first 90 postoperative days. There were 25 men and 23 women with a median age of 75 years (67-83). Eight were diabetic. Indications for surgery were rest pain (n = 23), ischaemic ulcer (n = 16), gangrene (n = 8) and popliteal aneurysm (n = 1). Measurements were made before reconstruction on the artery at the site of the distal anastomosis. After reconstruction flow measurements were made on the graft near the proximal and distal anastomoses together with a proximal graft pressure measurement. The peripheral resistance was calculated. Eleven grafts occluded and six patients died, four with patient grafts. Patients with graft occlusions had a significantly lower flow before (4 vs. 20 ml/min) and after (60 vs. 110 ml/min) reconstruction and a higher peripheral resistance, (1238 vs. 625 mPRU) than patients with patent grafts. The most significant differences were found in the femorodistal bypass grafts. The transit time flowmeter was easy to use. The flow before and after reconstruction as well as the peripheral resistance could be used for the prediction of graft function within 90 days of surgery.

Aged↗
PubMed1993

Volume blood flow measurements with a transit time flowmeter: an in vivo and in vitro variability and validation study.

A transit time flowmeter, Transonic TC101 (Transonic Inc., USA) has been evaluated to study volume flow. Two flow probes, 4 and 6 mm, were used. The experiments were carried out in vivo on the carotid arteries (n = 16) in sheep and in vitro against a pre calibrated rotational pump. Exsanguination measurements, n = 32, were used for the calculation of the error of measurement in vivo. The error of measurement in vitro was calculated on 11 different flow rates from 0 to 150 ml min-1. The variability in vivo was evaluated using data from 10, 30 s measurement periods with a 30 s pause between measurements. The variability in vitro was evaluated at three flow rates (46, 78, and 113 ml min-1). Five 1-min measurements with a 1-min pause between measurements were made. The error of measurement in vivo was 12.05% and in vitro 5.50% (4 mm probe) and 14.90% (6 mm probe). In vivo the variability was between 1.1 and 4.4% and in vitro between 1.5 and 11.2%. The correlation coefficients between the flowmeter on the one hand and exsanguination and the rotational pump on the other were 0.99, 0.99 (4 mm probe) and 0.98 (6 mm probe). It is concluded that the flowmeter has a small variability and error of measurement both in vivo and in vitro.

Animals↗
PubMed1992

The acute thrombogenicity of an infection-resistant rifampicin-soaked Dacron graft: an experimental study in sheep.

Every effort to reduce synthetic graft infection is welcome and when designing antibiotic-bonded grafts it is important not to increase graft thrombogenicity. In order to study the acute thrombogenicity of rifampicin-soaked gelatin-sealed Dacron grafts compared with untreated gelatin-sealed Dacron grafts, an experimental carotid artery sheep model was used. Twenty sheep were anaesthetised and 7-cm-long 5-mm-wide externally supported gelatin-sealed knitted Dacron grafts were sutured end to end into each carotid artery after excising a portion of that vessel. Test grafts had previously been immersed for 15 min in a rifampicin solution (1 mg ml-1) while control grafts were immersed in physiological saline for 15 min. There were two groups with 10 sheep in each. In one group the blood flow through the grafts was unrestricted but in the second the flow was restricted to 25 ml min-1. Platelets from sheep labelled with 111In and sheep fibrinogen labelled with 125I were injected intravenously. The isotope activities were continuously measured proximally and distally over the grafts for 4 h. With unrestricted flow 4 out of 10 rifampicin-soaked grafts occluded compared with 2 out of 10 control grafts (N.S.). Time to occlusion, thrombus weight, platelet and fibrinogen activity did not differ. In the restricted flow group 9 out of 10 rifampicin-soaked grafts occluded compared with 6 out of 10 control grafts (N.S.). The time to occlusion did not differ. The thrombus weight in the rifampicin group was significantly higher compared with the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

The effect of a combined thromboxane receptor- and synthesis-antagonist on platelet, fibrinogen and leucocyte uptake in ePTFE grafts: an experimental study in sheep.

Arterial expanded polytetrafluoroethylene (ePTFE) grafts were interpositioned in the common carotid arteries of 20 adult sheep. This model was used to study the effect of a combined thromboxane receptor- and synthesis-antagonist, Ridogrel (R 68070), on acute graft patency and platelet, fibrinogen and leucocyte uptake. The animals were randomised to treatment (n = 10) or control groups (n = 10). Treatment was given as an intravenous injection with Ridogrel of 8 mg kg body weight-1. The flow in one of the two inserted grafts was restricted to 25 ml min-1. Autologous 111In-labelled platelets, 125I-labelled fibrinogen and 99m-Tc-labelled leucocytes were injected intravenously and the radioactivity over the vessels measured before and after graft insertion using the gamma scintillation technique. After graft insertion the measurements continued for 4 h at two separate points over the proximal and distal anastomosis areas. In the treatment group six out of 10 grafts with restricted flow remained patent compared with nine out of 10 grafts with flow reduction in the control group (N.S.). The median thrombus weights did not differ significantly. There was no difference in the platelet and fibrinogen activities at the proximal anastomosis but distally the animals receiving treatment had a significant reduction during the first 2 h of the experiment. The leucocyte activity in the treatment group compared to the control group did not differ proximally but distally the activity was significantly higher during the last 3 h of the experiment. In the group with unrestricted flow all grafts in both groups remained patent. The thrombus weight was significantly lower in the treatment group compared with the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

The effect of a thromboxane receptor antagonist on acute ePTFE arterial graft thrombogenicity--an experimental study in sheep.

ePTFE interposition grafts in the common carotid arteries of 16 adult sheep were used to study the effect of a thromboxane receptor antagonist. Vapiprost (GR 32191, Glaxo research group, London, UK). After insertion of the grafts the sheep were randomised to treatment (n = 8) or control (n = 8). Treatment was given as an intravenous injection with GR 32191 of 1 mg/kg body weight. The flow in one of the two inserted grafts was restricted from normal (190 ml/min) to 25 ml/min. Autologous 111-In labelled platelets and human 125-I labelled fibrinogen were injected intravenously. The radioactivity over each graft was measured for 4 h at two separate points with a gamma scintillation technique. Due to technical complications immediately before the start of the measurements one sheep in each group was excluded from the study. In the treated group three out of seven grafts with restricted flow occluded compared to all seven grafts with a flow reduction in the control group (p less than 0.05). The grafts with unrestricted flow occluded in two of seven in both groups. In the open grafts with unrestricted flow the fibrinogen activity was significantly reduced in the treated group compared to the control group. The platelet activity was not significantly reduced. It is concluded that GR 32191 significantly reduced the fibrinogen uptake as well as graft occlusions of ePTFE grafts in a low flow situation.

Acute Disease↗