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Biomedical subjects

B Eklöf

Publications and source records attributed to B Eklöf.

At least 19 recordsLinked to original sources

Charles Rob, Alfred Nobel and Aphrodite: the development of surgery for venous thromboembolism.

Charles Rob and the vascular surgeons at Strong Memorial Hospital have made significant contributions to the development of venology. Their impact on the surgical treatment of venous thromboembolism is emphasized. The technique for thrombectomy with temporary arteriovenous fistula is described. In a prospective randomized study from Sweden iliac vein patency was found in 76% of the operated group and 35% of the conservatively treated group after 6 months, and 77% versus 30%, respectively, after 5 years. A patent femoropopliteal vein with competent valves was found in 52% of the surgically treated patients compared with 26% of those treated conservatively after 6 months, and 36% versus 11%, respectively, after 5 years. Thrombectomy with temporary arteriovenous fistula is the author's method of choice to treat patients with acute iliofemoral venous thrombosis if the history of swelling of the thigh indicating iliac vein obstruction is less than 7 days' duration and the activity expectancy of the patient is more than 10 years.

Arteriovenous Shunt, Surgical

Surgical removal of an inferior vena cava thrombus.

Studies on the management of inferior vena cava (IVC) thrombosis have rarely focused upon the risk of later development of post-thrombotic syndrome of the lower limbs. From 1983-1989, 52 patients with ilio-femoral thrombosis with an extension of thrombus into the IVC were treated. In addition to lower limb pain and swelling, 12 (23%) patients had symptomatic pulmonary embolism on admission. Perfusion/ventilation pulmonary scans were positive in 63%. Twelve patients received only anti-coagulant treatment. Thrombectomy was attempted in 40 patients, but failed in 13 patients due to old thrombi. Twenty-seven patients had surgical removal of thrombus combined with anti-coagulation [temporary arterio-venous fistula (AVF) and IVC interruption (n = 15); AVF alone (n = 9); and without fistula n = 3)]. The mortality and morbidity were low and hospital stay was not prolonged. Thirty-eight legs were examined at 7-66 months (mean: 23 +/- 3) after initial treatment. The limbs in which the IVC thrombus could not be removed (n = 20) were symptomatic in 25% of patients, venous ulcer developed in 4 of 20 limbs. The ilio-femoral segment was patent in only 35%. The thrombectomised limbs (n = 18) were asymptomatic in 56%; none had developed ulcer and iliac patency was 72%. Doppler investigations and refilling times were normal in 39% of the thrombectomised limbs. All patients without surgical IVC thrombus removal developed contralateral deep venous thrombosis during the follow-up period. This study shows that femoro-ilio-caval thrombectomy is successful only in patients with a short history and fresh clot, and can be safely performed with low morbidity and mortality.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent

Venous function assessed during a 5 year period after acute ilio-femoral venous thrombosis treated with anticoagulation.

To determine the chronological changes of venous physiology following major thromboses, 20 patients were repeatedly examined for over 5 years after an acute ilio-femoral thrombosis which was treated with conventional anticoagulation. Radionuclide angiography showed that 70% of the patients had obstructive lesions of the iliac vein with only minor changes occurring from 6 months to 5 years. In spite of this, the plethysmographic maximum venous outflow increased from 31 to 45 ml/min/100 ml (P less than 0.001). The foot volumetric reflux did not change with time and about half of the patients had abnormal values. Venous reflux assessed by the refill time of foot vein pressure, deteriorated with time (P less than 0.05), and at 5 years all but one patient had a refill time less than 20 s. The muscle pump function, examined by foot volumetry, was abnormally low in about half of the patients throughout the study. The ambulatory foot vein pressure was constantly pathological (greater than 60 mmHg) in half of the patients and only two of 18 patients had normal values (less than 45 mmHg) at 5 years. Five patients with thromboses involving only the proximal veins had better physiological results than 15 patients with thromboses that extended to the peripheral veins. Three patients who developed venous claudication had iliac vein obstruction and an impaired venous outflow and three patients who developed venous ulcers had venous reflux and severe venous hypertension. Although venous outflow continuously improves following ilio-femoral thromboses, valvular competence and muscle pump function are constantly pathological, creating severe venous hypertension with a risk of post-thrombotic sequelae.

Anticoagulants

Long-term results of venous thrombectomy combined with a temporary arterio-venous fistula.

Forty-one patients with acute iliofemoral venous thrombosis were randomised to conventional anticoagulation or acute thrombectomy combined with a temporary arterio-venous fistula (AVF) and anti-coagulation. Follow-up after 5 years in 22 medical and 19 surgical patients revealed slightly more asymptomatic patients (37 vs. 18%) and less frequent severe post-thrombotic sequelae (16 vs. 27%) in the surgical group (N.S.). The iliac vein was more frequently (P less than 0.05) normal following thrombectomy (71 vs. 30%) as demonstrated by radionuclide angiography, but occlusion plethysmography showed an outflow capacity (61 vs. 45 ml/min/100 ml) that was not significantly better. There was no obvious difference in muscle pump function (EVrel) and reflux (Q/EVrel) assessed by foot volumetry. Still, the ambulatory venous pressure was significantly (P less than 0.05) lower in the surgical group. There was a tendency towards better results following thrombectomy in patients with fresh thrombosis and a successful initial procedure. Although the numbers of observations in many cases were too small to provide statistical evidence of benefit with venous thrombectomy + AVF, this procedure seems to improve the long-term outcome following acute iliofemoral venous thrombosis. Since the difference in outcome is not very striking, anticoagulation treatment is still an acceptable alternative.

Acute Disease

Plasma metabolic disturbances and reperfusion injury following partial limb ischaemia in man.

Despite efficient revascularisation procedures for vascular disease, the limb can occasionally be lost following reperfusion. One contributing factor might be the formation of oxygen free radicals. This study attempts to describe the conditions necessary for oxy-radical formation from adenine nucleotide breakdown products and the role of plasma creatine content as a marker of cellular injury. Twelve patients undergoing aortic reconstructive surgery were studied. Only partial ischaemia of the lower limbs was induced by the aortic clamping, since varying degrees of collateral circulation existed. Radial arterial and external iliac venous blood was obtained simultaneously before, during and after cross-clamping of the aorta, and plasma levels of ATP, ADP, hypoxanthine, phosphocreatine, creatine, creatinine and lactate measured using luminescence and spectrophotometry. Venous creatine content increased during ischaemia and was doubled 30 min after recirculation. This increase was possibly due to leakage following cellular injury agreeing with a previously observed decrease in muscle tissue creatine content. The iliac arterio-venous difference of hypoxanthine and lactate markedly increased immediately post-ischaemia, while the phosphocreatine difference decreased. Plasma hypoxanthine was abundant in the leg on reoxygenation. The existence of a xanthine oxidase system in skeletal muscle could produce favourable conditions for oxy-radical formation through hypoxanthine degradation, which may contribute to the known muscle tissue injury.

Adenosine Diphosphate

Plasma creatine determination using a luminescence method.

A new luminescence procedure based on the creatine kinase reaction was developed for measuring creatine in plasma. The method is highly applicable to small animal work where the amount of blood volume is critical. Only 20 microliter of sample is necessary for creatine analysis. Deproteinizing the plasma sample with ethanol at room temperature is convenient. This extraction method is adaptable to a clinical setting. The ethanol used in the extraction is compatible with the luminescence method but precipitated enzymes in the NADH spectrophotometric method because of the greater sample volume needed for analysis. The creatine concentration is stable in plasma for at least 1 hr in a final anticoagulant concentration of 10 mM EDTA. The correlation between the new luminescence method with the established NADH spectrophotometric method was excellent (r = 0.99). The accuracy of the within-run precision is high, with a mean coefficient of variation, 2-3%. Plasma creatine levels could be an important indicator denoting early cellular damage and of potential prognostic value. Preliminary studies in human muscle ischemia and early shock in rabbits revealed a significant increase in plasma creatine levels. Further investigations are necessary to evaluate its clinical importance.

Creatine

Follow-up evaluation of venous morphologic factors and function after thrombectomy and temporary arteriovenous fistula in thrombosis of iliofemoral vein.

Fifty-seven patients (58 post-thrombotic legs) treated with venous thrombectomy and temporary arteriovenous fistula for thrombosis of the iliofemoral vein were evaluated in a follow-up study regarding clinical, morphologic and functional aspects nine to ten months after thrombectomy. There were 33 men and 24 women, between 15 and 84 years of age (a mean of 51 years). The results of clinical examination revealed that 75 per cent of the patients had a good and 20 per cent a fair result of the treatment. No ulcers of the leg or venous claudication had developed. Venography (53 legs) demonstrated 61 per cent patency rate of the iliofemoral segment, although post-thrombotic changes were noted in 23 per cent. Venous femoral pressure measurement was normal in 82 per cent of 28 legs examined despite some proximal stenosis or occlusion. A good venous emptying with plethysmography was achieved in 29 per cent and foot volumetry showed normal peripheral venous function in 29 per cent. The results of this follow-up study, however short, reveal that venous patency can be restored to a high extent with good clinical result. Functionally, these patients may be at high risk for having sequelae develop later.

Adolescent

Pulmonary embolism in acute iliofemoral venous thrombosis.

Serial perfusion lung scanning and chest radiography were used to study the incidence of pulmonary embolism in patients with acute iliofemoral venous thrombosis. The efficacy of conventional anticoagulation and surgical thrombectomy in controlling embolism and the risk of creating emboli during thrombectomy were also evaluated. Lung scans obtained on admission in 49 patients were normal in 37 per cent, inconclusive in 18 per cent and positive for embolism in 45 per cent of the patients. Symptoms suggestive of embolism were present in only 24 per cent of the patients and correlated poorly with lung scans. Massive embolism was present in only two patients. Additional, usually asymptomatic, emboli developed within one month in 21 per cent of 29 patients treated conservatively with anticoagulation alone and in 20 per cent of 20 patients having acute thrombectomy combined with a temporary arteriovenous fistula and systemic anticoagulation. Only one conservatively treated patient required caval interruption. Pulmonary embolism, usually of minor degree, is thus present in nearly every other patient with acute iliofemoral venous thrombosis. Anticoagulation alone or in conjunction with thrombectomy and arteriovenous fistula in most cases effectively prevents further embolization and the risk of creating additional emboli by the surgical procedure is insignificant.

Adolescent

Indications for angiography and its optimal performance in patients with Raynaud's phenomenon.

Fifty-two patients with Raynaud's phenomenon of the upper extremity were examined by angiography because of suspected organic stenosis or occlusions in areas available for reconstructive vascular surgery. Different vasodilatating treatments were compared either singly or combined: blockade of the brachial plexus, intraarterial injections of phentolamine or reserpine, body warming, and orally administered alcohol. Body warming in combination with 4 mg phentolamine gave optimal vasodilatation within the shortest time and without vasospasm after local cold provocation in patients with sympathetically induced vasospasm, enabling a clear visualization of organic lesions. A proper vasodilatation was also obtained after blockade of the brachial plexus or reserpine injection combined with body warming, but not until 40 min after the start of the treatments.

Angiography

Revascularization of popliteal and below-knee arteries with polytetrafluoroethylene.

The expanded polytetrafluoroethylene (PTFE) graft (Gore-tex) is the most frequently used synthetic graft when an alternative to autologous saphenous vein is required. Early results have been encouraging. In the present paper we report on 6 years of results from 153 above-knee (AK) femoropopliteal bypass grafts, 74 below-knee (BK) femoropopliteal bypass grafts, and 54 femorotibial/peroneal bypass grafts. The main indication for the vascular reconstruction was severe ischemia. Preventive antibiotics were given to 95% of the patients. Minimum observation time was 1 year after implantation. There was no operative death. Graft infection was seen in less than 5% of patients. The 6-year cumulative limb salvage rate was 87% for patients with severe ischemia in the AK femoropopliteal bypass group, 59% for those in the BK femoropopliteal bypass group, and 57% for those in the femorotibial/peroneal bypass group. The graft patency rate was 88% at 2 years and 78% at 6 years for the AK femoropopliteal bypass group, for whom the operative indication was disabling claudication, and 81% and 68%, respectively, when the indication for the vascular procedure was severe ischemia. The cumulative graft patency rate was 53% and 43% at 2 and 6 years, respectively, after implantation of BK femoropopliteal bypass grafts and 43% and 39% for femorotibial/peroneal bypass procedures. The expanded PTFE (Gore-tex) graft seems therefore to be a good alternative when an autologous vein is not available, even for reconstructions well below the knee joint.

Adult

Deep venous thrombosis, pulmonary embolism and acute surgery in thrombophlebitis of the long saphenous vein.

Twenty-eight consecutive cases of acute superficial thrombophlebitis of the long saphenous vein above the knee were reviewed concerning presence of asymptomatic deep venous thrombosis and pulmonary embolism and early clinical results after surgical treatment. Contrast phlebography of the ipsilateral leg revealed asymptomatic involvement of major deep veins of the thigh or calf in 4 of 21 examined patients. Perfusion lung scanning and chest radiography demonstrated typical segmental perfusion defects consistent with pulmonary embolism in two of ten examined patients. High ligation and stripping of the phlebitic veins gave prompt cure in 19 patients, though in two who were simultaneously treated with anticoagulants there was troublesome bleeding. Simple high ligation was performed in nine patients without complications, but four of them had protracted phlebitic pain. The results indicated that preoperative phlebography and lung scanning are helpful in detecting associated asymptomatic disorders and for planning therapy in patients with clinically isolated, superficial thrombophlebitis of the long saphenous vein. The treatment of choice is acute high ligation with removal of all phlebitic veins. If anticoagulation is indicated because of concomitant deep venous thrombosis or pulmonary embolism, the initial procedure should preferably be limited to high ligation.

Adult

Retroperitoneal fibrosis with large-vessel obstruction. An uncommon vascular disorder.

Five cases are presented in which retroperitoneal fibrosis had entrapped the inferior vena cava and/or aorta and caused occlusive vascular disease. The diagnosis was known preoperatively in two cases and was made at laparotomy in the others. The fibrosis in one case was caused by abdominal tuberculosis. In another case it was most probably secondary to an earlier trauma to the back. No cause could be established in the other three cases. CT scanning is valuable for identifying the lesion. Venous thrombectomy with arteriovenous fistula formation was successful in cases presenting with deep venous thrombosis.

Adult

Iliac vein obstruction associated with acute iliofemoral venous thrombosis. Results of early reconstruction using polytetrafluoroethylene grafts.

The results of iliac vein reconstruction performed early after secondary iliofemoral venous thrombosis were retrospectively evaluated. The review comprised seven patients who underwent acute thrombectomy combined with cross-femoral (4 cases) or iliocaval (3 cases) bypass procedures using polytetrafluoroethylene (PTFE) grafts. The clinical course, graft patency and venous physiology were studied. Five patients had a satisfactory clinical course, but one patient died of postoperative complications and another underwent leg amputation after 20 months. Contrast and radionuclide phlebograms showed that only two grafts were still patent after two years, but only one of these was still patent five years postoperatively. Clinical symptoms and physiologic parameters correlated poorly with graft patency, demonstrating the necessity of phlebography in evaluating patency rates after venous surgery. Our study indicates that early venous reconstruction using PTFE grafts does not result in satisfactory long-term patency rates. Further development of graft materials suitable for the venous system is required.

Acute Disease

Thrombectomy with temporary arteriovenous fistula: the treatment of choice in acute iliofemoral venous thrombosis.

The treatment of choice in acute iliofemoral venous thrombosis is still controversial. This prospective randomized study compares the results of conventional anticoagulation of 32 patients with the results obtained in 31 patients undergoing acute thrombectomy combined with a temporary arteriovenous fistula and anticoagulation. Early complications were few in both treatment groups, and significant pulmonary embolism developed in only one conservatively treated patient. At 6-month follow-up in all surviving patients, leg swelling, varicose veins, and venous claudication were more frequent after conservative treatment. Only 7% (2 of 27) of these patients were completely free from postthrombotic symptoms compared with 42% (10 of 24) of the operated patients (p less than 0.005). Contrast phlebography demonstrated an excellent venous outflow through the iliofemoral segment in 35% (9 of 26) of the conservatively treated and in 76% (16 of 21) of the operated patients (p less than 0.025). Open femoropopliteal veins with competent valves were recorded in 26% (7 of 27) in the conservative group and in 52% (12 of 23) in the thrombectomy group (p less than 0.05). Thus thrombectomy combined with arteriovenous fistula decreases early symptoms and preserves venous outflow and valvular function better than conservative treatment. This procedure is therefore recommended for young patients with acute iliofemoral thrombosis to avoid development of incapacitating postthrombotic sequelae.

Acute Disease

Popliteal artery injury in Kuwait.

While there is an abundant literature on popliteal artery injury secondary to penetrating trauma, few reports deal with popliteal artery injury caused by severe blunt trauma with or without fracture. Eight cases of popliteal artery injury are described. Seven of the patients had sustained blunt trauma, usually resulting also in damage to bone and soft tissues. The popliteal vein was involved in five of the injuries. The time lag between causal trauma and vascular repair averaged 25 hours. Delay was due mainly to failure to consult the vascular surgeon at an early stage. Leg amputation was necessary in two cases. Two patients died. The importance of early recognition of the vascular injury and appropriate surgical measures was illustrated in this small series of patients from a developing Middle Eastern country. Adequate fasciotomy, venous repair, use of intraoperative Doppler and repeated postoperative débridement are discussed in connection with management.

Adult

Intramuscular pressure, blood flow, and skeletal muscle metabolism in patients with venous claudication.

Nine patients with chronic iliac vein obstruction and venous claudication were investigated. Intramuscular pressure was measured in the anterior tibial and the deep posterior compartments in both legs at rest and during exercise. The pressures were significantly higher in the leg with iliac vein obstruction (39 +/- 10 mm Hg) than in the contralateral leg (26 +/- 12 mm Hg) at rest as well as during exercise (60 +/- 16 mm Hg and 41 +/- 15 mm Hg, respectively) in the deep posterior compartment. Similar changes were observed in the anterior tibial compartment. Muscle water content was higher (P less than 0.01) in the obstructed leg and contributes to the explanation for the high intramuscular pressure in this leg. Muscle blood flow, adenosine triphosphate, phosphocreatine, and lactate were determined in the gastrocnemius muscles at rest and at exercise. Muscle blood flow, measured with the 133xenon clearance technique, was lower in the obstructed leg (17.5 ml/min, 100 gm) than in the control leg (28.1 ml/min, 100 gm) during exercise. Lactate increased more (P less than 0.05) in the obstructed leg. It is suggested that pain in venous claudication is caused by the high intramuscular pressure, and therefore fasciotomy may be useful in the treatment of this disorder.

Adenosine Triphosphate