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Dive into the research topics where Knud Henrik Tønnesen is active.

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Featured researches published by Knud Henrik Tønnesen.


CardioVascular and Interventional Radiology | 1988

Percutaneous transluminal angioplasty of the superficial femoral artery by retrograde catheterization via the popliteal artery

Knud Henrik Tønnesen; Philip Sager; Agnete Karle; Lars Onsberg Henriksen; Bo Jørgensen

We report the results of 50 angioplasty procedures via the popliteal artery. A 3-year follow-up including control of blood pressures at ankle and toe levels show results comparable to reports in the literature. This new approach for angioplasty of the superficial femoral artery and eventually of coexisting iliac lesions enables treatment of previously inaccessible lesions. The technique is especially suited for lesions close to the takeoff of the superficial femoral artery.


Scandinavian Journal of Clinical & Laboratory Investigation | 1978

Treatment of severe foot ischaemia by defibrination with ancrod: a randomized blind study.

Knud Henrik Tønnesen; Ph. Sager; Johs. Gormsen

Forty-two patients, mean age 68 years, with severe leg ischaemia were randomly treated with placebo or by controlled defibrination with ancrod for 3 weeks. Plasma fibrinogen concentration was kept at about 20% of normal in the ancrod treated group. The two groups proved to be well matched regarding factors which could affect the degree of ischaemia. Objective measurements showed a significant rise in ankle and toe systolic blood pressure in the ancrod group lasting for 3 months. There was no rise in distal blood pressure in the control group. In the ancrod treated group the toe and ankle systolic pressures rose about 8 mmHg, but this was not accompanied by an improvement in the clinical course.


Annals of Surgery | 1978

Preoperative estimation of run off in patients with multiple level arterial obstructions as a guide to partial reconstructive surgery.

I. Noer; Knud Henrik Tønnesen; Ph. Sager

Preoperative measurements of direct femoral artery systolic pressure, indirect ankle systolic pressure and direct brachial artery systolic pressure were carried out in nine patients with severe ischemia and arterial occlusions both proximal and distal to the ingvinal ligament. The pressure-rise at the ankle was estimated preoperativcly by assuming that the ankle pressure would rise in proportion to the rise in femoral artery pressure. Thus it was predicted that reconstruction of the iliac obstruction with aorta-femoral pressure gradients from 44 to 96 mm Hg would result in a rise in ankle pressure of 16–54 mm Hg. The actual rise in ankle pressure one month after reconstruction of the iliac arteries ranged from 10 to 46 mm Hg and was well correlated to the preoperative estimations. In conclusion, by proper pressure measurements the run-off problem of multiple level arterial occlusions can be evaluated. Thus the result of successful partial reconstruction can be assessed preoperatively.


European Journal of Vascular Surgery | 1991

Femoro-popliteal Artery Occlusions Treated by Percutaneous Transluminal Angioplasty and Enclosed Thrombolysis" Results in 55 Patients

Knud Henrik Tønnesen; P. Holstein; E. Andersen

Removal of fibrin from the site of a newly dilated femoro-popliteal occlusion may be an attractive way of preventing rethrombosis. A double balloon catheter with a dilating tip balloon and an occlusive balloon 10, 15 or 20 cm approximately were introduced percutaneously. Following successful dilatation of femoro-popliteal occlusions, the balloons were inflated on both sides of the lesion. The dilated segment was then isolated from the circulation. Through a sideport between the balloons 5 mg of tissue type plasminogen activator and 1000 IU of heparin were installed within the segment for 30 min. The authors report the results of 53 technically successful dilatations of femoro-popliteal occlusions followed by enclosed thrombolysis. A 100% patency at 3 months was noted in 33 patients having one to three run-off arteries, and the one year patency was 90%. In 20 patients, with no infrapopliteal run-off artery, four rethrombosis occurred within 24 h, and the one year patency was 62%. This difference is significant. (Log rank test, Chi-square = 4.73, p less than 0.05). We conclude that enclosed thrombolysis prevents early reocclusion following PTA of femoro-popliteal occlusions provided that at least one infra-popliteal artery is patent.


Scandinavian Journal of Clinical & Laboratory Investigation | 1987

Why do patients with severe arterial insufficiency get pain during sleep

Rolf Jelnes; Jens Bülow; Knud Henrik Tønnesen; Niels A. Lassen; P. Holstein

Simultaneous measurement during 24 h of mean arterial blood pressure (MABP) and forefoot subcutaneous adipose tissue blood flow (SBF) was undertaken in eight patients (15 feet) with different degrees of arterial insufficiency. The recordings were undertaken with the patients in the supine position only. The MABP decreased by 19 +/- 9% from awake to asleep independently of symptomatology. In two limbs with normal circulation, SBF decreased by 8 +/- 7%. In five limbs with arterial insufficiency but no rest pain SBF decreased by 16 +/- 8%, and in eight limbs with ischaemic nocturnal rest pain, SBF was reduced by 32 +/- 12% during sleep. It is concluded that nocturnal hypotension is the major aethiological factor for the symptom ischaemic nocturnal rest pain.


CardioVascular and Interventional Radiology | 1994

Comparison of efficacy in crossing femoropopliteal artery occlusions with movable core and hydrophilic guidewires.

Knud Henrik Tønnesen; Jens Bülow; P. Holstein; Ulf Helgstrand

PurposeCompare the recanalization rate of femoropopliteal occlusions between movable core wire guide (MG) and hydrophilic guidewire (HG).MethodsConventional PTA technique was used, followed by enclosed thrombolysis. The MG was used for all patients in the first 2 years, the HG in the following 2 years. Baseline characteristics were similar for the two groups of patients.ResultsRecanalization of 124 femoropopliteal occlusions was attempted. Technical success was achieved with the MG in 45 of 59 procedures; 42 procedures were clinically successful. Using the HG, technical success was achieved in 35 of 65 procedures; clinical success was achieved in 29 cases (p < 0.0048). At 1-year follow-up, 32 extremities improved after treatment with MG and 22 extremities after treatment with HG (p < 0.035).ConclusionThe results suggest that the MG should be the first choice in recanalization of femoropopliteal occlusions.


CardioVascular and Interventional Radiology | 1981

Direct measured systolic pressure gradients across the aorto-iliac segment in multiple-level-obstruction arteriosclerosis

I. Noer; J. Præstholm; Knud Henrik Tønnesen

Patients with severe ischemia due to multilevel obstructions in the leg arteries both above and below the groin were assessed preoperatively by intraarterial brachial and femoral artery pressure measurements. The systolic pressure drop along aortoiliac obstructions was compared to the angiographic findings. A consistent pressure gradient was found in the various types of arterial occlusions.In patients with occlusion of both the aorta and the iliac arteries, the systolic pressure drop was about 60% (range, 50–78%, SD 9%). The various types of iliac artery occlusions resulted in quite uniform systolic pressure drops of about 50% (range 35–68%, SD 9%). In contrast, the systolic pressure drop along different types of iliac stenoses showed a wide variation, ranging from a minimal drop to about 60%. The degree of stenosis on the angiogram was correlated significantly with the pressure drop. Due to large variations, however, this angiographic information was found to be useless in the individual patient. No difference in the pressure drop was found between cases in which rich and poor collateral networks were visualized.


European Journal of Vascular Surgery | 1988

The cause of ischaemic nocturnal rest pain

Rolf Jelnes; Jens Bülow; Knud Henrik Tønnesen; N. A. Lassen; P. Holstein

Adipose tissue blood flow in the forefoot was measured simultaneously with mean systemic arterial blood pressure over 24 hours in 8 patients (15 feet) with different degrees of arterial insufficiency. Mean systemic arterial pressure decreased by 19 +/- 9% during sleep, irrespective of symptomatology. In two limbs, with a normal peripheral circulation, blood flow decreased by 8 +/- 7%. In five limbs with arterial insufficiency, but no rest pain, blood flow decreased by 16 +/- 8% and in eight limbs with ischaemic nocturnal rest pain blood flow was reduced by 32 +/- 12% during sleep. It is concluded that nocturnal hypotension is a major factor in the production of nocturnal ischaemic rest pain.


European Journal of Vascular Surgery | 1988

The incidence of ureteral obstruction secondary to aorto-femoral bypass surgery. A prospective study

Lars Onsberg Henriksen; Sten Mejdahl; Frank Petersen; Knud Henrik Tønnesen; P. Holstein

Hydronephrosis is reported to be an infrequent complication of aorto-femoral bypass operations. To define the true incidence of this complication, renography (131I-Hippuran) and renal scintigraphy (99 Technetium) were performed both pre- and postoperatively on 56 asymptomatic patients following successful aortic reconstruction. No patient developed signs of ureteral obstruction. It is concluded that hydronephrosis is a rare complication to aorto-femoral bypass surgery and postoperative control is only indicated in patients with symptoms from the urinary tract.


CardioVascular and Interventional Radiology | 1981

Supplementary angiography when lumbar angiograms faile to demonstrate the vessels to the leg

I. Noer; J. Præstholm; Knud Henrik Tønnesen

The peripheral run-off arteries were insufficiently visualized due to occlusions in the aorto-iliac segments in studies of 10 patients (15 legs) in 183 consecutive aorto-femoral angiograms. Guided by a combination of the Doppler technique and fluoroscopy, the non-opacified and pulseless common femoral artery was catheterized. Angiography through this catheter usually showed patency of a part of the common femoral artery but occlusion of the superficial femoral artery. The deep femoral and crural arteries were well preserved. Intra-arterial pressure measurements showed larger pressure gradients along the occluded aorto-iliac segments in one-third of the patients with non-visualized leg arteries as compared with gradients in patients with similar proximal and distal occlusions but with good opacification of the leg arteries.In previous cases, non-visualization of the leg arteries was considered as representing non-reconstructable lesions by our vascular surgeons. The findings in the present study showed that in these patients surgical reconstruction of only the aorto-iliac segments will suffice to save the limb from amputation.

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Jens Bülow

University of Copenhagen

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