Search

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.

1. Twenty-four hour continuous recording of xenon (133Xe) wash-out from the forefoot was performed on patients with normal circulations (n = 10) and on patients with different degrees of arterial insufficiency (n = 36). 2. During day hours the calculated subcutaneous blood flow in the forefoot was on average the same in patients with normal circulations and in patients with different degrees of arterial insufficiency (mean: 2.0 ± 0.8 ml min−1 100 g−1). 3. During sleep the blood flow nearly doubled in patients with normal circulations; no systematic change was seen in patients with intermittent claudication. In patients with severe ischaemia, i.e. having rest pain, the blood flow decreased by approximately 50%. 4. The changes in local blood flow may be due to changes in local sympathetic tone and to changes in local perfusion pressure.

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.

Regional 133Xe ventilation/perfusion studies were used to predict residual lung function after pulmonary resection. The accuracy of the method was good as checked by postoperative spirometry in 11 patients. In 25 patients with impaired lung function and pulmonary cancer, who were consecutively selected for surgery, the predicted postoperative maximal breathing capacities (MBC) ranged from 17 to 41 1/min-1 m-2. No patients became permanent pulmonary invalids. One patient died from myocardial infarction, 7 had transient pulmonary insufficiency and 17 patients survived operation without complications. Perfusion studies alone proved as reliable as perfusion/ventilation studies.

The residual kidney function was predicted from preoperative renography and determination of the glomerular filtration rate (GFR) in 57 patients undergoing unilateral nephrectomy for cancer, postrenal obstruction or renovascular hypertension. Postoperative GFR measurements were carried out 6-36 months after the operation. In eleven patients where the kidney removed had no function, no significant difference was found between pre- and postoperative GFR values. In 46 patients where the kidney removed had some function, the preoperative estimate was a little too high in only two patients. In this group, the postoperative GFR on an average amounted to 42 above the preoperatively predicted value. We conclude that the combination of 51Cr-EDTA clearance and renography is a reliable, non-invasive method for determination of the minimum residual kidney function before unilateral nephrectomy is carried out.

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.

The influence of renal function, measured by 51Cr-EDTA clearance, on morphine and morphine glucuronide kinetics has been studied in 13 patients after a single i.v. injection of morphine. Unconjugated morphine and morphine glucuronides were measured by a sensitive, specific RIA after extraction from plasma. No significant correlation was found between total body clearance of unconjugated morphine and 51Cr-EDTA clearance. However, patients with renal insufficiency had impaired elimination of morphine glucuronides, and the apparent clearance was significantly correlated with the 51Cr-EDTA clearance (r=0.94, p<0.001). A relatively long terminal elimination half-life of morphine was found in all patients (mean±SD: 9.2±2.5 h), irrespective of glomerular function.

Abstract: 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.

Plasma angiotensin II concentration gradients across the pulmonary vascular bed were measured during diagnostic renal venous/right heart catheterization in twenty-seven hypertensive patients with renal or renovascular disease. There was a linear correlation between the plasma angiotensin II concentration in mixed venous blood and in systemic arterial blood. The pulmonary angiotensin II production rate was measured in fourteen patients This parameter was linearly correlated with plasma renin concentration in systemic arterial blood. The plasma clearance of angiotensin II across the systemic vascular bed varied from 0.7 to 1.7 l/min, i.e. within a fairly narrow range.

The effect of ethanol (5-25 mM) on the galactose elimination kinetics in the intact liver was studied in the isolated perfused pig liver, using the steady-state infusion technique. Ethanol reduced galactose-Vmax, on average to 0·07 mmol/min kg liver in six experiments from 0·43 mmol/min kg obtained in control experiments without ethanol. Also Km was significantly reduced from 0·23 mmol/l plasma water to 0·03 mmol/l. Ethanol increased UDP-galactose ten-fold simultaneous with a rise in hepatic outflow ratio of lactate to pyruvate to about 300 from 10; this indicates that ethanol inhibits epimerase. In experiments with increasing galactose elimination rates, the concentration of galactose-1-P increased much less than the concentration of galactose, and the phosphorylation of galactose therefore seems to be rate-limiting. In vitro galactokinase is inhibited by galactose-1-P. In the present study ethanol increased galactose-1-P five to ten times, and the reduction of Vmax and Km by ethanol could be explained by uncompetitive inhibition by galactose-1-P with K1, about 0·1 mmol/l. Ethanol decreased UDP-glucose to about 40% and UTP to less than 5%, probably due to trapping as UDP-galactose. This may depress the forward transferase reaction, and therefore the other co-substrate galactose-1-P rises - and inhibits galactokinase.

The renal and cerebral blood flow was measured in six pigs after total devascularization of the liver. The animals died 21 to 26 h after the operation, with biochemical and electroencephalographic changes compatible with liver failure. The renal blood flow increased slightly, from 2.12 to 2.61 ml g−1· min−1, throughout the period of observation but did not differ significantly from that of the controls. Conversely, the cerebral blood flow decreased 38, from 1.30 to 0.80 ml · g−1· min−1, p < 0.05. The results failed to confirm a simultaneous decrease in cerebral and renal blood flow due to false neurotransmitters in liver failure, as previously suggested. The results do not support the suggested hypothesis that a substance produced by the liver is essential for renal function and perfusion, nor can they confirm that vasoactive material from the gut is responsible for the renal hypoperfusion in liver failure. The absence of renal hypoperfusion in the present preparation might be due to the exclusion of the failing liver from the circulation, giving indirect evidence to the theory that the vasoactive agent(s) responsible for the renal hypoperfusion in liver failure originates in the failing liver itself.

The clinical course was followed and the ankle and toe blood pressures were measured with the strain gauge technique on 5 occasions during 2 years in 43 patients with pain at rest and/or ischaemic ulceration due to severe ischaemia of the legs on the basis of occlusive arterial disease. Although arteriosclerosis of the legs in non-diabetic patients is generally considered a benign disease from the standpoint of limb survival, the critical level of TPI (systolic toe blood pressure/systolic arm blood pressure) was found to be 0.07 as a TPI below this value was associated with an overall 82% risk of amputation. With TPI above 0.07, the chance of successful conservative therapy was about 40%. Diabetics with severe ischaemia must be regarded as a high risk group in respect of amputation (64%) and lethality (64%). A variance analysis was made on the pressure data: In patients with low pressure peripheral vascular beds, the TPI must change more than 0.15 units from one examination to another before the alteration can be considered significant at the 99% confidence level.

133Xenon clearance technique as a measure of the blood flow per unit weight of muscle tissue has been compared to venous occlusion plethysmography in the calf of normal subjects. The comparison was made during reactive hyperemia and in the post-exercise period. In the first mentioned experiments, no agreement between the results by the two methods was obtained.In the experiments in the post-exercise period a highly significant correlation between the two methods was found in each experiment. The mean value of the muscle blood flow, calculated from 133Xenon clearance from six experiments, averages 113 per cent of the flow, measured simultaneously by plethysmography. The standard deviation in the 6 experiments was calculated to ± 63 per cent. The major part of this deviation is ascribed to the difficulty of such a comparison.

Abstract: 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.

The effect of head-up tilt on leg blood flow and segmental arterial blood pressures was studied in 21 patients with occlusion or severe stenosis of the common or superficial femoral artery. Arterial pressure was measured directly in the brachial artery, common femoral artery and popliteal artery. Relative change in blood flow in the leg during tilt was estimated by changes in arterio-venous oxygen differences and by the indicator dilution technique in nine patients. Head-up tilt caused a decrease in leg blood flow of 36% corresponding to an increase in total vascular resistance of 57%. Tilt did not change the pressure gradient from femoral to popliteal artery in the patients with occlusion of the superficial femoral artery, indicating that the flow resistance offered by the collateral arteries had increased. In a bilateral sympathectomised patient the increase in collateral resistance was almost absent indicating that the constriction of the collateral arteries is mainly mediated via sympathetic vasoconstrictor fibres.