Risk factor documentation in elective and emergency vascular surgical admissions

OBJECTIVES

this study investigates current practice of risk factor documentation in a vascular unit and compares variations in risk factor assessment between elective and emergency admissions.

METHODS

one hundred and forty-four patients who underwent vascular surgical intervention for atherosclerotic disease during the year 2000 were retrospectively identified from computerised database. Case note review collated demographic details, data on risk factor assessment and the nature of surgery. Data were analysed using SPSS statistical software.

RESULTS

the male to female ratio was 2.3:1 with a median (range) age of 73 (31-95) years. For 55 (38%) emergency admissions the following risk factors were not documented; ischaemic heart disease (8), diabetes mellitus (10), hypertension (10), smoking habit (13) and antiplatelet therapy (18). For 89 (62%) elective admissions the following risk factors were not documented; ischaemic heart disease (11), diabetes mellitus (9), hypertension (4), smoking habit (5) and antiplatelet therapy (19). Sixty-six (72.5%) routine admissions and 11 (20.8%) emergency admissions had estimations of serum cholesterol documented (chi(2) p < 0.001). There were no statistically significant differences in the documentation of other risk factors between the 2 groups.

CONCLUSION

risk factors are not documented consistently for emergency vascular surgical admissions. Staff education should aim to improve risk factor assessment for elective and emergency admissions to reduce cardiovascular events and possibly improve surgical outcome in patients with atherosclerotic disease.

A new on-line method for predicting aortic root dilatation during two-dimensional echocardiography in pediatric patients with Marfan syndrome using the sinus of valsalva to annulus ratio

The objective of this study was to determine if calculation of the sinus of Valsalva to annulus ratio (SOV/Ann) effectively screens for root dilatation (ARD) during two-dimensional (2D) echocardiography in young patients (1 month-15 years) with suspected or confirmed Marfan syndrome. The aortic root was imaged using 2D echocardiography (parasternal long-axis view) and the SOV/Ann ratio calculated/analyzed in 27 Marfan patients and 45 age-matched controls. All controls had a SOV/Ann ratio <1.45, and 82% of Marfan's with ARD had a SOV/Ann ratio 1.45. Five of the Marfan patients with ARD had a SOV/Ann ratio < 1.45 due to normalization of the SOV/Ann ratio because of pathologic annular enlargement. Determination of the SOV/Ann ratio allows rapid on-line screening for aortic root dilatation during 2D echocardiography. A SOV/Ann ratio 1.45 predicted ARD in young Marfan patients with a high degree of accuracy (sensitivity = 0.82, specificity = 1.00). Screening for ARD using the SOV/Ann ratio fails when annular dilatation has progressed to the degree that the SOV/Ann ratio normalizes (SOV/Ann < 1.45). In this subgroup of patients, determination of aortic root dilatation will have to be evaluated by standard methods.

The systemic effects of intermittent claudication are reversed by angioplasty

INTRODUCTION

exercise in patients with intermittent claudication causes systemic effects, the consequences of which are unknown. This study investigates whether successful PTA reverses the systemic effects.

PATIENTS AND METHODS

ten patients with IC were recruited prior to PTA. Having emptied their bladders and rested for 1 h, pre-exercise blood and urine samples were collected. Patients underwent treadmill exercise to maximum walking time and blood samples were collected at 10, 20 and 30 min. A second urine sample was collected at 60 min. Total antioxidant capacity (TAC) and von Willebrands Factor (vWF) were measured in blood and albumin/creatinine ratio (ACR) and retinol binding protein/creatinine ratio (RBP/Cr) in urine. Patients were recalled 2 weeks after successful angioplasty and the protocol repeated. Following PTA patients walked for a maximum of 5 min.

RESULTS

there was no significant change in vWF. Exercise in claudicants induced a significant increase in median ACR (pre/post exercise=0.85 p =0.03) and in median RBP/Cr (pre/post exercise=1.8 p =0.04). These changes were no longer evident after successful PTA. TAC was significantly different before and after angioplasty at all time intervals.

CONCLUSION

successful PTA reverses glomerular effects of exercise in claudicants. Future work should investigate the use of PTA in conjunction with exercise in the treatment of peripheral vascular disease.

The effect of acute normovolaemic haemodilution on blood transfusion requirements in abdominal aortic aneurysm repair

OBJECTIVE

to evaluate the impact of acute normovolaemic haemodilution (ANH) on the blood transfusion requirements in elective abdominal aortic aneurysm (AAA) repair in a single vascular unit.

METHODS

thirty-two patients underwent ANH during elective AAA repair between 1992 and 1997. The operation was performed by the same surgeon/anaesthetist team in 75% of cases. Their demographic details, type of aneurysm (infra-renal or supra-renal), preoperative blood cross match, use of intra-operative red cell salvage, blood loss, peri-operative bank blood requirements, pre-op and on-discharge haemoglobin levels and post-operative outcome were recorded. The results were compared to a group of 40 randomly selected patients (to represent the unit average) who underwent elective AAA repair by variable surgeon/anaesthetist teams without ANH in the same time period.

RESULTS

there were more supra-renal AAA repairs in the ANH group (8/32) than in the non-ANH group (0/40, p<0.01). ANH patients required significantly less blood transfusion peri-operatively (median 2 units) than the non-ANH patients (median 3 units, p=0.02). There were no other significant differences between the variables measured.

CONCLUSION

these results suggest that a dedicated team can achieve significant reductions in the use of heterologous blood transfusion compared to the vascular unit average experience by the effective use of ANH.

Responses of non-obese white children to treadmill exercise

OBJECTIVE

To determine the response to maximal treadmill exercise with the Bruce protocol in a cohort of healthy non-obese American children and adolescents.

STUDY DESIGN

A retrospective review of treadmill exercise studies on 347 white American children (188 boys, 159 girls) aged 5 to 18 years was performed with metabolic criteria to verify maximal exercise effort. Data on exercise endurance time, heart rate, blood pressure, and metabolic variables were assessed and compared between age groups and sexes by unpaired t testing and analysis of variance.

RESULTS

Exercise endurance time was lower in all age groups when compared with earlier published data. Girls had a lower endurance time than boys at all ages. There was no significant difference in maximum heart rate with respect to age or sex. The maximum systolic blood pressure and diastolic blood pressure increased with increasing age in both boys and girls. Boys had significantly higher maximum systolic blood pressure and diastolic blood pressure after 13 years of age. The maximum absolute oxygen consumption and indexed oxygen consumption showed similar trends for both sexes.

CONCLUSION

Lower exercise endurance times are seen despite physiologic evidence of maximal effort, raising the possibility that cardiovascular conditioning is reduced in contemporary American children.

Occupational respiratory diseases in South Africa--results from SORDSA, 1997-1999

OBJECTIVES

To describe the nature and extent of work-related respiratory diseases reported to the national Surveillance of Work-related and Occupational Respiratory Diseases in South Africa (SORDSA) reporting scheme. The causative agents and industrial categories in which they occurred are also characterised.

DESIGN

Voluntary monthly reporting of newly diagnosed cases by pulmonologists, occupational medicine practitioners and occupational health nurses.

SETTING

Medical and occupational health referral centres in the nine provinces of South Africa.

SUBJECTS

Cases were workers from non-mining industries or ex-miners, suffering from a newly diagnosed occupational respiratory disease, reported to SORDSA between October 1996 and December 1999.

OUTCOME MEASURES

Frequencies of reported occupational respiratory disease by year, reporting source, province and sex. Frequencies of short- and long-latency diseases by industry and causative agent.

RESULTS

There was incomplete reporting coverage of the nine provinces in the first 3 years. Reporting was most comprehensive from Gauteng, KwaZulu-Natal and the Western Cape. Diseases with long latency periods made up 76.2% of the cases. Pneumoconiosis, even in non-mining industries, was the most frequently reported disease, followed by inhalation accidents. Occupational asthma was the fourth most reported disease. Apart from the prominence of pneumoconiosis, the results obtained by SORDSA are similar to those from a British occupational lung disease surveillance scheme. This study showed that newly diagnosed cases of occupational lung disease occurred in many industries and were caused by a variety of agents.

CONCLUSION

SORDSA has contributed insight into the nature, extent and distribution of occupational respiratory diseases in South Africa. It has also highlighted important causes of occupational respiratory diseases in South Africa, as well as hazardous industries. The data indicate that South Africa has a widespread occupational lung disease problem, and provide a platform for targeted prevention strategies.

Erythropoietin with iron supplementation to prevent allogeneic blood transfusion in total hip joint arthroplasty. A randomized, controlled trial

BACKGROUND

The optimum regimen of epoetin alfa for prevention of allogeneic blood transfusion is unknown.

OBJECTIVE

To determine whether a modified regimen of epoetin alfa reduces allogeneic blood transfusion in patients undergoing hip arthroplasty.

DESIGN

Randomized, double-blind, multicenter trial comparing two modified dose regimens of epoetin alfa with placebo.

SETTING

13 teaching hospitals and 4 community hospitals in Canada.

PATIENTS

201 patients undergoing primary hip arthroplasty who had a hemoglobin concentration of 98 to 137 g/L and did not predonate blood.

INTERVENTION

Patients were assigned in a 3:5:5 ratio to receive four weekly doses of epoetin alfa, 40 000 U (high-dose; n = 44) or 20 000 U (low-dose; n = 79), or placebo (n = 78), starting 4 weeks before surgery. All patients received oral iron supplementation, 450 mg/d, for 42 or more days before surgery.

MEASUREMENTS

The primary end point was allogeneic transfusion. Secondary end points were thromboembolic events and change in reticulocyte count and hemoglobin concentration.

RESULTS

Both modified epoetin alfa regimens significantly reduced the need for allogeneic transfusion: Five (11.4%) patients in the high-dose group (P = 0.001) and 18 (22. 8%) patients in the low-dose group (P = 0.003) had transfusion, compared with 35 (44.9%) patients in the placebo group. The hematologic response was substantial in patients who received epoetin alfa. In the high-dose group, low-dose group, and placebo group, the preoperative increase in reticulocyte count was 58.8, 37. 0 and 1.8 x 10(9) cells/L (P < 0.001), respectively, and the increase in hemoglobin concentration was 19.5, 17.2, and 1.2 g/L (P < 0.001). The incidence of thromboembolic events did not differ among groups.

CONCLUSIONS

Both modified epoetin alfa regimens were effective compared with placebo in reducing allogeneic transfusion in patients undergoing hip arthroplasty. Patients who received high-dose epoetin alfa had the lowest transfusion rate.

The degree of saturation of fatty acids influences post-ingestive satiety

Two studies were designed to compare the effects on post-ingestive satiety of manipulating the degree of saturation of fatty acids, at a fixed chain length (18 C atoms), in a fixed energy (5.68 MJ for males; 3.97 MJ for females), high-fat (55% energy) lunch meal. Two different groups of twenty subjects (ten males and ten females) took part in each study. All forty subjects were of normal weight and aged between 18 and 36 years. Study 1 compared the effects of fat A (oleic blend, high in monounsaturated fatty acids (MUFA)) with those of fat B (linoleic blend, high in polyunsaturated fatty acids (PUFA)) and fat C (stearic-oleic blend, high in saturated fatty acids (SFA)). Study 2, which was designed to confirm and extend the findings of Study 1, compared the effects of fats A, B and C with those of fat D (a linoleic-oleic blend). Energy and nutrient intakes were monitored for the rest of the day and for the following day. Profiles of hunger, fullness and other sensations were monitored by continuous tracking and end-of-day questionnaires. In each meal the fat content was exclusively composed of one particular type (A, B, C or D) and was divided equally between the main course and dessert. Study 1 revealed a significant effect of fat type (degree of saturation) on intake of nutrients at the following (dinner) meal (smallest F[2,36] 3.38, P < 0.05), on post-ingestive ratings of motivation to eat (smallest F[2,36] 4.18, P = 0.02) and on energy intake over the whole test day (F[2,36] 3.39, P < 0.01). Subjects consumed significantly more energy after consumption of the lunch containing fat A than after the lunches containing fats B or C and there was a trend for these effects to continue into the second day. In Study 2, fat C produced more similar effects on appetite to fat A and there was a tendency for subjects to consume more over the whole test day when they had consumed the lunch containing fat A than when they had consumed the lunch containing fat B. Furthermore, when the data from fat conditions A and B in both studies were combined (n 40) the results of Study 1 were confirmed. Overall, the results of these short-term studies indicate that PUFA may exert a relatively stronger control over appetite than MUFA and SFA.

Procainamide for rate control of postsurgical junctional tachycardia

This study was conducted to determine the efficacy of procainamide therapy for rapid rate control of postoperative junctional tachycardia (JT). Postoperative JT is one of the most difficult forms of tachycardia to manage. Reported success with a variety of treatments of JT in infants and children has been inconsistent and limited. Rate control using procainamide was achieved in 17 children having rapid JT (heart rate >200 beats/min) between 1986 and 1997. In the first 5 patients (protocol A), following a loading dose of 3 mg/kg over 20 minutes, a continuous procainamide infusion was initiated at a rate of 20 microg/kg/min. The infusion dose was increased in 10 microg/kg steps every 30 minutes to 40-120 microg/kg/min until the heart rate decreased below the target rate of 180 beats/min. In the other 12 patients (protocol B), after a higher loading dose of 10 mg/kg the infusion rate was increased every 10-15 minutes until the heart rate decreased below the target rate of 180 beats/min. Procainamide decreased JT rates in all patients but the response was significantly faster in protocol B. In the patients treated with protocol A, pretreatment JT rates ranged from 203 to 240 (213+/-17) beats/min and decreased to 195+/-10 beats/min at 2 hours (p = ns), 186+/-8.8 at 4 hours (p<0.02), and 179+/-8 at 6 hour postinitiation of PA. In protocol B, pretreatment JT rates ranged from 201 to 240 (218+/-17) beats/min and decreased to 183+/-20 beats/min at 2 hours (p<0.001) and 171+/-12 at 4 hours after starting the procainamide therapy. The mean duration to decrease JT rates below the target rate of 180 beats/min was 3.2+/-1.1 hours in protocol B compared to 6.4+/-3.8 hours in protocol A (p<0.02). Eight of 12 patients in protocol B achieved rate control below the target rate of 180 beats/min within 4 hours despite remaining on significant inotropic support. The procainamide infusion rates to maintain heart rates below 180 beats/min were 40-120 (68.4+/-22.1) microg/kg/min. No proarrhythmia, bradycardia, or significant hypotension was observed. In this series procainamide provided safe, effective, and rapid rate control of JT occurring in the immediate postoperative period.

The SNF1 kinase complex from Saccharomyces cerevisiae phosphorylates the transcriptional repressor protein Mig1p in vitro at four sites within or near regulatory domain 1

Mig1p is a zinc finger protein required for repression of glucose-regulated genes in budding yeast. On removal of medium glucose, gene repression is relieved via a mechanism that requires the SNF1 protein kinase complex. We show that Mig1p expressed as a glutathione-S-transferase fusion in bacteria is readily phosphorylated by the SNF1 kinase in vitro. Four phosphorylation sites were identified, i.e. Ser-222, Ser-278, Ser-311 and Ser-381. The latter three are exact matches to the recognition motif we previously defined for SNF1 and lie within regions shown to be required for SNF1-dependent derepression and nuclear-to-cytoplasmic translocation.

Vascular surgical society of great britain and ireland: systemic effects of exercise in claudicants are associated with neutrophil activation

BACKGROUND: Claudication induces potentially harmful systemic effects which may be mediated through free radicals and neutrophil activation. This study examined the impact of these mechanisms on renal tubular function. METHODS: Flow cytometry was used to determine CD11b expression by neutrophils and monocytes, and expression of P selectin (CD62P) by platelets, in 16 patients with intermittent claudication and eight matched controls before and at intervals after exercise. Total antioxidant capacity (TAC) and von Willebrand factor (vWF) were measured at similar intervals. Renal tubular function was assessed before and 60 min after exercise by assay of retinol binding protein : creatinine ratio (RBP : Cr) in urine. All patients and none of the controls had a significant exercise-induced fall in ankle pressure. Fluorescein isothiocyanate-labelled monoclonal antibodies against CD11b and CD62P were added to blood and analysis was performed on the flow cytometer within 72 h. RESULTS: There were no significant differences in monocytes, platelets or vWF between patients and controls over time. There was a significant change in RBP : Cr following exercise in patients (median 4.2 (95 per cent confidence interval 2.4-85.2); P </= 0.01, Wilcoxon test) but not controls (2.7 (-1 to 7.5); P not significant). See Table above. CONCLUSION: Renal tubular function was adversely affected by acute exercise in claudicants. TAC was higher in claudicants at rest and was increased after exercise suggesting an increased free radical challenge. Neutrophil activation is significantly different between claudicants and controls before and after exercise, and may provide a link between free radical generation and renal tubular injury.

Vascular surgical society of great britain and ireland: angioplasty reverses the systemic effects of exercise in intermittent claudication

BACKGROUND: The choice between exercise training and percutaneous transluminal angioplasty (PTA) in the treatment of intermittent claudication (IC) remains controversial. Exercise is known to induce systemic effects in claudicants. This study aimed to determine whether such systemic effects are reversed by PTA. METHODS: Ten patients with IC were recruited before PTA. Having emptied the bladder and rested for 1 h, pre-exercise blood and urine samples were collected. Patients underwent treadmill exercise to their maximum walking time and further blood samples were collected at 10, 20 and 30 min. A second urine sample was collected at 60 min. Total antioxidant capacity (TAC) and von Willebrand factor (vWF) were measured in blood, and albumin : creatinine ratio (ACR) and retinol binding protein : creatinine ratio (RBP : Cr) in urine. Patients were recalled 2 weeks after successful angioplasty and the protocol was repeated. Statistical analysis was by Wilcoxon signed rank test. RESULTS: Following PTA, all patients walked for 5 min on the treadmill. All patients had a significant exercise-induced fall in ankle pressure that was reversed by PTA. Changes in TAC are shown in the Table. There was no significant change in vWF. Exercise in claudicants induced a significant increase in median ACR (pre/post exercise (pre-exercise value divided by post-exercise value) 0.8; P = 0.03) and in median RBP : Cr (pre/post exercise 1.8; P = 0.04). These changes were no longer evident after successful PTA. CONCLUSION: Exercise-induced changes in renal glomerular (ACR) and tubular function (RBP : Cr) in claudicants were reversed by successful angioplasty. PTA reduced the systemic TAC before and after exercise suggesting a reduced free radical challenge.

Vascular surgical society of great britain and ireland: patients with a failed infrainguinal bypass graft have abnormal lipid metabolism

BACKGROUND: Dyslipidaemias adversely affect vascular tone, endothelial function and platelet activation. Abnormal lipid metabolism has not been established as a risk factor for infrainguinal bypass graft failure. Lipid metabolism was evaluated prospectively in patients with patent and occluded grafts. METHODS: Twenty-eight patients with failed infrainguinal grafts (group 1) were identified from a prospective computerized database. Twenty matched controls with functioning grafts (group 2) were recruited from a graft surveillance programme. Fasting blood samples were analysed for triglyceride (TG), high-density lipoprotein (HDL) and cholesterol. A newly devised rapid TG tolerance test was conducted with analysis of TG at 1, 2 and 2.5 h. Endothelial lipoprotein lipase (LPL) was measured 30 min after intravenous administration of heparin 50 units kg-1. RESULTS: The cholesterol : HDL ratio was significantly higher in group 1 than group 2 (median 6.0 (range 3. 1-10.0) versus 4.7 (2.3-9.4); P = 0.0008, Mann-Whitney test) as was fasting TG (2.6 (1.0-6.3) versus 1.7 (0.6-4.7) mmol l-1; P = 0.03). The area under the curve of the TG tolerance test was not significantly different (P = 0.08); however, the 2.5-h levels of TG were significantly different between the groups (group 1, 2.0 (0.5-6. 6) mmol l-1; group 2, 1.2 (0.3-6.8) mmol l-1; P = 0.01). LPL was significantly lower in group 1 (52.4 (2.2-235.9) versus 86.8 (28. 6-281.5) mmol/l; P = 0.04). CONCLUSION: These data suggest that abnormal lipid metabolism is a significant risk factor for infrainguinal graft occlusion. This study provides a rationale for randomized trials of lipid-modifying therapies in patients undergoing arterial reconstruction for peripheral vascular disease.

In utero treatment of fetal complete heart block with terbutaline. A case report

BACKGROUND

Isolated fetal complete heart block is an uncommon finding, with a mortality rate of 20-30%. Various treatment modalities have been reported, with no consistent success.

CASE

Fetal complete heart bock was diagnosed in a 30-year-old woman at 29 weeks' gestation. She had an elevated antinuclear antibody and anti-SSA antibody titer. Fetal cardiac decompensation was detected at 32 weeks. After a trial of intravenous isoproterenol without significant side effects, she was treated with oral terbutaline. An increase in the fetal ventricular rate and complete resolution of hydrops fetalis occurred. A male infant was delivered by cesarean section, at term, and underwent cardiac pacemaker implantation at 4 days of age.

CONCLUSION

The treatment of fetal complete heart block is controversial. Premature delivery with cardiac pacing is associated with high morbidity and mortality. We report prenatal treatment with oral sympathomimetic medication, which allowed delivery to be delayed until term, with a successful outcome.

Vascular surgical intervention for complications of cardiovascular radiology: 13 years' experience in a single centre

This study investigates incidence and outcome of iatrogenic vascular complications needing surgery in a single vascular unit serving interventional vascular radiology and interventional cardiology. Evolution of diagnostic and interventional cardiovascular radiology, along with the introduction of non-surgical therapies for such complications, may have influenced the number of vascular complications requiring emergency surgery. Vascular surgical data were collected from information prospectively entered on computerised database and case note review. Radiology data were collated from prospective entries in logbooks and computerised database. In all 24,033 cardiovascular radiological procedures were performed between 1984 and 1996 (61% cardiac), numbers increasing annually. During this period, 62 patients (40 peripheral; 22 cardiac) required emergency surgical intervention after radiological procedures. Mean age was 61.9 years (range 1-92 years), male to female ratio was 1:1. The absolute number of cases requiring surgical intervention peaked in 1989, subsequently reducing annually. Sites of vascular injury included common femoral artery (40), brachial artery (6), iliac artery (6), popliteal artery (5), other (5). A total of 87 vascular surgical operations was performed (range 1-6 operations per patient). Interventions included thrombectomy/embolectomy (29), bypass grafting (16), direct repair (27). Seven major amputations were performed (two bilateral). Mortality after surgery was 9.7%. Mean inpatient hospital stay was 11.3 days (range 0-75 days). A Poisson regression model indicates a 5% reduction in risk for each successive year of observation; however, this did not reach statistical significance (P = 0.16, 95% CI 12% decreased risk to 2% increased risk). The risk of surgical intervention after diagnostic or interventional cardiovascular radiology is diminishing but still requires vigilance. Necessity for surgical intervention is associated with a high risk of morbidity and mortality.

Compression ultrasonography for false femoral artery aneurysms: hypocoagulability is a cause of failure

OBJECTIVES

False femoral artery aneurysm is an occasional complication of percutaneous cardiovascular radiological procedures. Compression ultrasonography causes thrombosis non-invasively, reducing need for operative intervention. The technique fails in a proportion of cases. Analysis was undertaken to identify causes of failure.

DESIGN

Prospective open study.

MATERIALS AND METHODS

Patients presenting with false femoral artery aneurysm since 1984 were identified from a computerised database (BIPAS). Since 1993 compression ultrasonography has been performed as first line treatment according to a standard protocol. Prospectively collected ultrasonographic data and case notes were reviewed to identify causes of failed compression.

RESULTS

False femoral artery aneurysm occurred as a complication in 32/26,687 (0.12%) cardiovascular radiological procedures. Eighteen aneurysms were treated by compression. The technique was successful in 11/18 (61%) cases but primary failure occurred in seven cases. Six out of seven had bleeding abnormalities (Chi-squared analysis with Yates correction 10.55, p = 0.0012), four were anticoagulated and compression was subsequently successful following reversal of warfarin therapy in three of these patients. In 4/18 cases surgical repair was necessary.

CONCLUSION

Compression ultrasonography is an effective treatment of false femoral aneurysms, however, hypocoagulability is a significant cause of failure. For patients in whom anticoagulation cannot be reversed, primary surgical repair should be considered.

A medium-term intervention study on the impact of high- and low-fat snacks varying in sweetness and fat content: large shifts in daily fat intake but good compensation for daily energy intake

Thirty-six normal-weight, habitual snackers (eighteen males, eighteen females) completed a medium-term intervention study designed to examine the tendency of four different types of snacks, varying in nutrient (low- (LF) or high-fat (HF) and sensory properties (sweet (SW) or non-sweet (NSW)), to influence the control of appetite and to adjust daily energy intake. Subjects were exposed to each snack category for a 3-week period and were asked to consume a minimum number of snacks each day so that at least 25% of their daily energy intake would be derived from the test snacks. Energy and macronutrient intakes from the test snacks were calculated every day and also from other eating episodes (using 3 d food diary records) during the third week of snack exposure. Subjects consumed more energy/d from the SW snacks than from the NSW snacks, with most energy being consumed from the HF/SW snacks (3213 kJ) and least energy from the LF/NSW snacks (1628 kJ). This differential snack intake remained stable across the whole snack exposure period. Total daily energy intake did not differ significantly during exposure to any of the four snack types. Furthermore, the encouragement to eat freely from the test snacks did not lead to daily overconsumption of energy when compared with pre-study intakes. Hence, the level of snack consumption was largely compensated for by the energy consumed from the rest of the eating pattern. Although daily energy intake during exposure to the HF snacks was an average of 364 kJ higher (NS) than that during exposure to the LF snacks, the clearest and most significant effect of snack consumption was on daily macronutrient intake. Appreciable consumption of the HF snacks raised the percentage of total daily energy intake consumed as fat from 37 to 41% (P < 0.01). In contrast, the LF snacks reduced daily fat intake to 33.5% (LF/SW, P < 0.05; LF/NSW, NS) of total daily energy. The results, therefore, suggest that, in habitual snackers, generous consumption of LF snacks, when compared with HF snacks, is an effective strategy to reduce fat intake so that it approaches the recommendations of dietary guidelines without increasing total daily energy intake.

Double-outlet right ventricle (tetralogy of Fallot type) associated with anomalous origin of the left coronary artery from the right pulmonary artery: report of successful total repair in a 2-month-Old infant

The case reported herein demonstrates the rare association of double-outlet right ventricle (tetralogy of Fallot type) with anomalous origin of the left coronary artery from the pulmonary artery. It is the first reported successful total surgical repair in an infant.

The progression and correction of duplex detected velocity shifts in angiographically normal vein grafts

OBJECTIVES

To review the sensitivity of duplex scanning and angiography at detecting vein graft stenoses in patients on a graft surveillance programme.

DESIGN

Prospective, open, non-randomised study.

PATIENTS AND METHODS

Since February 1993, 143 patients with 148 grafts (70% in situ, 30% reversed) have attended postoperative infrainguinal vein graft surveillance for a minimum of 6 weeks. Fifty-seven graft stenoses in 57 grafts were identified by duplex scanning as a localised high velocity jet. Angiography was performed in all except 12 patients.

RESULTS

Angiography confirmed a duplex abnormality in all but 10 patients. Of these, five patients remain stable and asymptomatic with a persisting duplex abnormality. The remaining five patients, although asymptomatic, exhibited disease progression on duplex and surgical intervention confirmed significant stenoses, which were successfully treated.

CONCLUSION

The results suggest that duplex scanning is a reliable imaging modality for detecting vein graft stenoses. Selection for surgical correction can be made, in some circumstances on the basis of clinical and ultrasound criteria alone.

Sympathetic skin response and patient satisfaction on long-term follow-up after thoracoscopic sympathectomy for hyperhidrosis

OBJECTIVES

To determine effect of sympathectomy for hyperhidrosis on sympathetic skin response (SSR) during long-term follow-up. Patient satisfaction was assessed and surgical complications noted.

DESIGN

Prospective, Open, Non-randomised study.

MATERIALS AND METHODS

Patients who had undergone bilateral thoracoscopic sympathectomy for hyperhidrosis underwent postoperative assessment of SSRs. A 15 mA stimulus was applied over the median nerve contralateral to the sympathectomy and evoked electrodermal activity was recorded from the sympathectomised palm using a Dantec Counterpoint Mk 2. Patient satisfaction with surgery was assessed by questionnaire and visual analogue score (0-1.0).

RESULTS

Of 26 patients, 21 were female. Mean (range) age was 23 (9-36) years. Mean (range) follow up was 39 (4-138) months. 12% of cases had residual or recurrent symptoms. Median (range) patient satisfaction was 0.83 (0.06-1.0). In 7/52 palms recurrent SSRs were not detected. Repeated measures analysis of variance found amplitude of SSR to be of low significance with respect to time since surgery (F = 0.48; p = 0.49) and incidence of compensatory sweating (F = 2.38; p = 0.14).

CONCLUSION

Thoracoscopic sympathectomy for hyperhidrosis is an effective procedure. Following sympathectomy SSRs are not permanently abolished, but return of SSRs does not correspond with symptom recurrence. As such, SSRs are a poor tool for objective assessment of long-term outcome following sympathectomy.

Effects of meloxicam, compared with other NSAIDs, on cartilage proteoglycan metabolism, synovial prostaglandin E2, and production of interleukins 1, 6 and 8, in human and porcine explants in organ culture

Some non-steroidal anti-inflammatory drugs (NSAIDs) can accelerate joint damage in osteoarthritis by enhancing the production of pro-inflammatory cytokines or inhibiting cartilage proteoglycan synthesis. Meloxicam, a new NSAID, was compared with standard NSAIDs for its effect on proteoglycan synthesis and degradation in human and porcine cartilage explants, as well as the production of prostaglandin E2 (PGE2) and interleukins 1 and 6 by human synovial tissue explants in-vitro. Meloxicam at submicromolar concentrations inhibited synovial PGE2 production but, up to therapeutic drug concentrations (< or = 4 microM), did not affect synovial production of the pro-inflammatory cytokine IL-1. In contrast, hydrocortisone, 10 microM, a positive control, inhibited release of this cytokine, and indomethacin, 100 microM, increased its production. The lack of effects of meloxicam were evident irrespective of intrinsic IL-1 bioactivity of the synovia, production of IL-1 inhibitors or time of incubation. Production of the part anti-inflammatory cytokine IL-6, was significantly increased by therapeutic concentrations of meloxicam, as well as by indomethacin. Another major pro-inflammatory cytokine, IL-8, was unaffected by therapeutic concentrations of meloxicam. Meloxicam, 0.1-4.0 microM, did not affect cartilage proteoglycan production whereas indomethacin, 100 microM, significantly reduced synthesis of these macromolecules. Thus meloxicam, at concentrations within the therapeutic range and at which pronounced inhibition of prostaglandin production is evident, affects neither cartilage proteoglycan production nor the production of those cytokines likely to be important in cartilage destruction.

In utero management of hydrops fetalis caused by critical aortic stenosis

Hydrops fetalis is rarely associated with congestive heart failure caused by obstructive left-sided heart lesions. There are rare cases of live born neonates with critical congenital valvar aortic stenosis and hydrops reported in the literature, all with fatal outcomes. This report describes, to the best of our knowledge, the first two newborns who were diagnosed prenatally to have hydrops fetalis caused by critical valvar aortic stenosis, who were treated prenatally with digoxin and who postnatally had successful percutaneous balloon aortic valvuloplasty. Both patients had not only left but right ventricular dysfunction. We speculate that right ventricular dysfunction was a contributing factor in the development of hydrops in these patients and in utero medical therapy with digoxin is associated with resolution of the hydrops before delivery.

Vaccination against Haemonchus contortus with denatured forms of the protective antigen H11

As part of a systematic examination of the protective epitopes on H11, groups of sheep were vaccinated with preparations of purified H11 used untreated (group A), or progressively denatured (linearized) by incubation with sodium dodecyl sulphate (SDS) (group B) or by boiling with SDS in the presence of dithiothreitol (group C). All the sheep developed antibodies which bound to the untreated H11. When challenged with 10,000 infective larvae of Haemonchus contortus the mean levels of protection relative to the mean values for adjuvant controls were 99.8%, 85% and 79% for faecal egg counts and 95%, 79% and 54% for worm burden at post-mortem for groups A, B and C respectively. The H11-specific antibodies inhibited the microsomal aminopeptidase activity of H11 in vitro up to 80%. The levels of inhibition by sera from individual animals correlated with levels of protection with r2, of 0.69-0.87.

Pharmacokinetics and pharmacodynamics of intra-graft iloprost in femorodistal bypass surgery

Intra-graft injection of the prostacyclin analogue, iloprost, was performed at the end of femorodistal bypass procedures in 12 patients with severe peripheral arterial occlusive disease. Iloprost plasma levels were measured and compared with changes in haemodynamics. There was a high initial iloprost plasma level (mean 625 pg/ml) which dropped to a mean of 50 pg/ml after 15 min. This correlated with an immediate reduction in systolic blood pressure which had returned to pretreatment levels after 15 min. In contrast, the vascular resistance distal to the graft showed a reduction after 5 min which was maintained for at least 20 min after iloprost injection and the mean blood flow through the graft increased steadily throughout the same period of measurement. The study showed an effect of iloprost on blood pressure which correlated with plasma levels, but the time course of the changes in distal vascular resistance and graft blood flow demonstrated an effect more prolonged than the half-life of iloprost.

Postoperative assessment of a modified surgical approach to repair of tetralogy of Fallot. Long-term follow-up

BACKGROUND

After repair of tetralogy of Fallot, right ventricular (RV) dilation has been associated with increased risk of ventricular arrhythmias and sudden death. To address this, a modified repair was developed.

METHODS AND RESULTS

We followed two postoperative groups: group 1 (n = 20) received repair of tetralogy of Fallot with the modified technique with transatrial ventricular septal defect closure, a short infundibular incision with avoidance of muscle resection, and patch expansion of the RV outflow tract; group 2 (n = 22) received repair of tetralogy of Fallot by the traditional technique with ventricular septal defect closure through a ventriculotomy with resection of obstructing muscle. Six patients were excluded from further follow-up: two patients, one in each group, who required RV-pulmonary artery conduit placement at original repair; one patient in group 1 who developed double-chamber RV; and three patients, two in group 1 and one in group 2, who were lost to our follow-up < 5 years postoperatively. We compared postoperative findings > 10 years after repair. Despite similar residual RV outflow tract stenosis and obligatory pulmonary insufficiency by examination and Doppler echocardiography, RV size was smaller in the modified group, as reflected by RV/left ventricle on M-mode echocardiography (0.66 +/- 0.22 versus 0.81 +/- 0.17, P = .02), cardiothoracic ratio (0.53 +/- 0.04 versus 0.58 +/- 0.06, P = .03), and QRS duration (126 +/- 19 versus 143 +/- 23, P = .03). RV systolic function was more impaired in group 2, as reflected by decreased systolic tricuspid annulus excursion on two-dimensional echocardiography. Exercise endurance time was significantly higher in group 1 patients. Lown grade 4 ventricular ectopy on ambulatory ECG was present in three patients in group 2 and none in group 1.

CONCLUSIONS

The modified technique results in significantly less RV dilation and better preservation of RV function at late follow-up.

Interstitial 6q deletion and Prader-Willi-like phenotype

A third case of an interstitial deletion of the long arm of chromosome 6 with clinical features mimicking Prader-Willi syndrome (PWS) is presented. Although preliminary clinical evaluation in each case suggested PWS, further review revealed that the features in all three cases are not completely compatible with the characteristic findings in Prader-Willi syndrome. Furthermore, the deletions in the three cases do not show a consistent region of overlap. Consequently, no particular band or region in 6q can be defined as associated with obesity. However, our findings confirm the suggestion of Villa et al. in 1995, that individuals with a PWS phenotype who are cytogenetically and molecularly negative for a deletion of 15q11-q13 should be examined for a deletion of 6q.

Characterization of AMP-activated protein kinase beta and gamma subunits. Assembly of the heterotrimeric complex in vitro

There is growing evidence that mammalian AMP-activated protein kinase (AMPK) plays a role in protecting cells from stresses that cause ATP depletion by switching off ATP-consuming biosynthetic pathways. The active form of AMPK from rat liver exists as a heterotrimeric complex and we have previously shown that the catalytic subunit is structurally and functionally related to the SNF1 protein kinase from Saccharomyces cerevisiae. Here we describe the isolation and characterization of the two other polypeptides, termed AMPKbeta and AMPKgamma, that together with the catalytic subunit (AMPKalpha) form the active kinase complex in mammalian liver. Sequence analysis of cDNA clones encoding these subunits reveals that they are related to yeast proteins that interact with SNF1, providing further evidence that the regulation and function of AMPK and SNF1 have been conserved throughout evolution. The amino acid sequence of the beta subunit is most closely related to SIP2 (35% identity), while the amino acid sequence of the gamma subunit is 35% identical with SNF4. We show that both AMPKbeta and AMPKgamma mRNA and protein are expressed widely in rat tissues. We show that AMPKbeta interacts with both AMPKalpha and AMPKgamma in vitro, whereas AMPKalpha does not interact with AMPKgamma under the same conditions. These results suggest that AMPKbeta mediates the association of the heterotrimeric AMPK complex in vitro, and will facilitate future studies aimed at investigating the regulation of AMPK in vivo.

Health effects of passive smoking in adolescent children

OBJECTIVE AND DESIGN

To study the effects of passive smoking on health in adolescent schoolchildren by questionnaire, spirometry and laboratory investigations.

SETTING

Two schools in the Vanderbijlpark area.

PARTICIPANTS

Seven hundred and twenty-six high-school children of average age 16 years.

OUTCOME MEASURES

Lung function, serological abnormality or historical (i.e. questionnaire) evidence of ill health.

RESULTS

The prevalence of respiratory illness before and after 2 years, respiratory symptoms, earache over the past year, low birth weight and learning difficulties were found to be significantly increased in the children exposed to parenteral smoke in the home, especially those exposed to maternal smoking. Spirometric and laboratory parameters, however, were not affected by passive smoking.

Loss of sinus rhythm after total cavopulmonary connection

BACKGROUND

Total cavopulmonary connection (TCPC) to repair functional single ventricle involves the sinus node area, in contrast to the Fontan procedure. We compared ECG findings after TCPC and Fontan to evaluate the impact of the cavopulmonary connection on sinus rhythm postoperatively.

METHODS AND RESULTS

The Fontan group consisted of 17 patients repaired at 7.8 +/- 3.1 years of age (mean +/- SD): 11 for tricuspid or pulmonary atresia (TA/PA) and 6 for single ventricle. The TCPC group consisted of 19 patients repaired at 5.1 +/- 3.2 years of age (mean +/- SD) (P < .001): 9 for TA/PA, 4 for single ventricle, and 6 for hypoplastic left heart syndrome. Mean follow-up after Fontan was 7.7 +/- 2.7 years versus 2.8 +/- 1.6 years for TCPC (P < .001). Preoperative ECGs on all TCPC patients showed sinus rhythm (SR), whereas 16 of 17 Fontan patients had SR and one had nonsinus atrial rhythm (NSAR) since birth. On the first postdischarge ECG, 12 of 19 TCPC patients (63%) were in SR, 4 were in junctional rhythm (JR), and 3 were in NSAR. In comparison, 15 of 17 Fontan patients (88%) were in SR with 1 of 17 in NSAR and 1 in supraventricular tachycardia (P < .05 with chi 2 test). By 2 years postoperatively, only 6 of 15 TCPC patients available for follow-up (40%) were in SR, with 7 of 15 in JR and 2 of 15 in NSAR. By contrast, 13 of 17 Fontan patients (76%) remained in SR, with 1 in NSAR and 3 in JR (P < .05 with chi 2 test). TCPC patients with loss of SR did not differ from other patients in the group in age at repair, preoperative diagnosis, or surgeon performing the procedure.

CONCLUSIONS

This significant incidence of loss of SR temporally related to surgery suggests that operative compromise of the sinus node area is common with TCPC.

Direct access surgery

Evolving surgical practice in the UK is imposing increasing pressures on surgical outpatient clinics. A Direct Access Surgery (DAS) programme was evaluated in which otherwise healthy patients with simple surgical conditions presenting little diagnostic difficulty were referred directly to hospital for surgical operation without attending the outpatient department. Specific referral criteria for DAS were devised. Appropriate surgical conditions or procedures included hernias, vasectomies, cystic scrotal swellings, subcutaneous lumps and skin lesions, symptomatic gallstones, varicose veins and ingrowing toenails. Over a 12 month period, 105 patients were referred for DAS and 102 underwent operation. There was a low incidence of inaccurate diagnosis (< 2%) and inappropriate referral (< 1%). DAS was well received by both General Practitioners (GPs) and patients. Implementation of such programmes may result in considerable savings of outpatient time and resources.

Falsely elevated ankle pressures in severe leg ischaemia: the pole test--an alternative approach

Ankle-branchial pressure indices (ABPIs), measured by sphygmomanometer and Doppler probe, are an accepted index of chronic leg ischaemia. However, tibial artery sclerosis or calcification decreases compliance, producing falsely elevated cuff occlusion pressures. Arterial cannulation is invasive and impractical, but by elevating the foot and measuring the height at which the Doppler signal disappears, ankle systolic pressure in mmHg can be derived. Using an 8MHz Doppler apparatus and calibrated pole, ankle systolic pressures measured by sphygmomanometer and elevation were compared in 49 severely ischaemic legs (40 patients). ABPIs were derived by dividing ankle systolic pressure by brachial pressure. Median (interquartile range) ABPI assessed by sphygmomanometry was 0.46 (0.35-0.56). Median ABPI measured by leg elevation was significantly lower at 0.21 (0.14-0.30), p < 0.0001, Wilcoxon. In 20 patients undergoing in situ vein bypass grafting, direct transducer-derived pressure measurements were obtained. Median ABPI for this method was 0.15 (0.11-0.27). No significant difference was found when compared with ABPIs derived by elevation, median 0.2 (0.13-0.31), p = 0.324, however median ABPI measured by sphygmomanometry was significantly higher at 0.37 (0.27-0.6), p = 0.0008. Correlation of elevation with transducer-assessed pressure measurements (r = 0.88) was closer than with cuff-derived measurements (r = 0.69). Pressures derived by leg elevation provide a more accurate index of severe leg ischaemia than sphygmomanometry, although the technique is limited to assessing pressures of less than approximately 60 mmHg. Falsely elevated ABPIs may underestimate the extent of disease in patients assessed for vascular reconstruction.

Chronic muscle stimulation improves ischaemic muscle performance in patients with peripheral vascular disease

There is currently no established treatment for intermittent claudication with proven long term benefit. Exercise classes have been shown to improve walking distance. Chronic electromyostimulation (CEMS) a method of stimulating skeletal muscle has effects on normal muscle which may also benefit claudicants. We investigated the effects of one month of CEMS on claudicants in a single blind placebo controlled study. Patients were randomised to either CEMS (treatment) or transcutaneous nerve stimulation (TENS) placebo. The effects of the two modalities were assessed using the conventional measures of claudicating distance (CD), maximum walking distance (MWD), ankle-brachial pressure index (ABPI) and pressure recovery time (PRT). Muscle performance was assessed by the fatigue index (FI) a technique determining the decrease in ischaemic muscle response to repeated contraction. After 4 weeks treatment the CEMS group showed significant improvements in their median CD (88 to 111) and MWD (118 to 158); this was not seen in the control group. Muscle performance also increased significantly during the 4 weeks of treatment in the CEMS group but not in the control group. These changes were not maintained after CEMS was stopped. This pilot study suggests that CEMS may well have a role to play in the treatment of intermittent claudication though a number of further studies need to be undertaken.

Pharmacological reduction of the systemically damaging effects of local ischaemia

Many patients with intermittent claudication are encouraged to exercise. However, transient exercise-induced muscle ischaemia results in systemic vascular endothelial injury associated with increased vascular permeability manifest as an increase in urinary albumin excretion. Repetitive systemic vascular endothelial injury leads to accelerated atherogenesis and may explain the high cardiovascular mortality rate of claudicants. Oxpentifylline, a haemorheological agent, has recently been shown to prevent vascular endothelial injury in animal models. A double-blind, placebo-controlled, cross-over trial was undertaken to determine the effect of oxpentifylline on exercise-induced systemic vascular endothelial injury in 20 claudicants. Urinary albumin, expressed as a creatinine ratio (ACR), was measured before and 1 and 2 hours after standardised exercise following 1 week treatment with either active drug or placebo. Oxpentifylline reduced the median (range) 1 hour post exercise increase in ACR from 0.35 (-0.46-12.72) to 0.02 (-6.00-14.10) mg/mmol. (p = 0.030, z = 2.2 Wilcoxon rank sign test). These results confirm that local ischaemia is associated with a potentially deleterious systemic effect and that it may be possible to attenuate this pharmacologically. The clinical significance of this is yet to be determined.

Microproteinuria predicts the severity of systemic effects of reperfusion injury following infrarenal aortic aneurysm surgery

Noncardiogenic pulmonary dysfunction can be demonstrated in all patients following elective aortic aneurysm repair and is a cause of postoperative morbidity. Aortic clamping and reperfusion initiate a systemic inflammatory response producing endothelial damage and increases in vascular permeability. In the lung this is manifest as pulmonary edema and in the kidney as detectable increases in urinary protein excretion (microproteinuria). Immunoassay of low-level protein excretion appears to provide an index of the systemic effects of local reperfusion injury and may allow early prediction of complications such as pulmonary edema. Hourly urinary albumin and IgG excretion was measured in 40 patients undergoing infrarenal aortic aneurysm repair and expressed as ratios to urinary creatinine (albumin/creatinine ratio [ACR] and IgG/creatinine ratio [IgGCR]). These were compared to clinical outcome. Pulmonary dysfunction was assessed according to PaO2:FiO2 ratios and chest radiography. Within 180 minutes of beginning surgery all patients had significant increases in ACR and IgGCR. Ten patients who manifested respiratory dysfunction had significantly higher ACRs at 4 hours (median 84.8, 95% confidence intervals, range 47.7 to 136) than patients who made uneventful recoveries (median 16.6, 95% confidence intervals, range 7.9 to 31.7). IgGCR increases paralleled that of ACRs. Differences persisted for 24 hours. Urinary protein excretion rises rapidly during aortic surgery. The degree of increase appears to predict development of pulmonary dysfunction. This simple test may provide a rational basis for evaluation of therapeutic modalities to limit reperfusion injury in these patients.

Modified technique for balloon valvuloplasty of critical pulmonary stenosis in the newborn

OBJECTIVES

We report our experience in eight consecutive neonates who underwent attempted balloon dilation as an initial therapy for critical valvular pulmonary stenosis, and we review in detail technical modifications that improved the success rate.

BACKGROUND

Balloon dilation of the pulmonary valve has become the treatment of choice for valvular pulmonary stenosis in children and adults. There are few reports of its effectiveness in critical pulmonary stenosis in the newborn. In this setting, application of the technique of balloon dilation has been limited by the ability to advance the necessary guide wires and catheters across the stenotic, often near-atretic, pulmonary valve.

METHODS

The pulmonary valve was crossed in all patients. When this could not be accomplished with an end-hole catheter, a soft guide wire was advanced directly across the pulmonary valve through the end-hole catheter positioned in the right ventricular outflow tract below the valve. Initial predilation was achieved in all patients by using a coronary dilation catheter in an effort to facilitate introduction of the definitive balloon dilation catheter. Definitive dilation with a balloon diameter of > or = 110% of the diameter of the pulmonary valve annulus was possible in six patients.

RESULTS

Right ventricular pressure declined from a mean value of 108 +/- 32 mm Hg to a mean value of 49 +/- 11 mm Hg after balloon dilation, with no change in heart rate or aortic pressure in these six patients after definitive balloon dilation.

CONCLUSIONS

The results of this small series suggest that critical valvular pulmonary stenosis in the newborn can be successfully treated by transluminal balloon valvuloplasty.

Ultrasonographic screening for abdominal aortic aneurysm in an urban community

As part of the Birmingham Community Aneurysm Screening Project, 3500 men aged 65-75 years from 20 urban general practices were invited for aortic ultrasonographic screening at their own general practitioner's surgery; 2669 (76.3 per cent) attended. Compliance rates varied between catchment areas, from 52.1 per cent for inner-city areas to 89.6 per cent for suburbs. Successful aortic imaging was achieved in 97.3 per cent of scans. Aortic diameter > 29 mm occurred in 219 patients (8.4 per cent) and 79 (3.0 per cent) with a diameter > 40 mm were referred for vascular surgical assessment; 140 patients with an aortic diameter of 29-40 mm are currently undergoing follow-up by serial ultrasonographic examinations at intervals of 3 months at their doctor's surgery. Risk factor analysis revealed ischaemic heart disease in 21.9 per cent of men with aneurysm, compared with 11.6 per cent in those without (P < 0.001); 18.3 per cent of men with aneurysm had had a previous myocardial infarction and 13.2 per cent had peripheral vascular disease, compared with 7.4 per cent (P < 0.001) and 8.0 per cent (P < 0.01) respectively of those without. No association was found between aneurysm and hypertension or diabetes. Community-based aortic screening is an inexpensive, effective method of diagnosis of aneurysm, with high compliance from the at-risk cohort of an urban population. Such screening programmes may help to reduce the mortality rate from aortic aneurysm rupture.

Adjuvant prostanoid treatment during femorodistal reconstruction

A prospective randomized placebo-controlled trial was conducted to determine the effects of the stable prostacyclin analogue iloprost on early graft patency and hemodynamic parameters during femorodistal reconstruction for critical leg ischemia. Peripheral resistance and graft blood flow were measured using an operative Doppler flowmeter and graft pressure transducer. Postoperative graft surveillance was continued at 1-month and then at 3-month intervals by duplex Doppler ultrasonography, measurement of ankle-brachial pressure indices, and intravenous digital subtraction angiography when indicated. In patients receiving 3000 ng of iloprost (n = 45) infused into the graft on completion there was an immediate mean decrease in peripheral resistance of 44% that persisted to skin closure in comparison with controls (n = 38) in whom no such decrease in resistance occurred (p < 0.001, Wilcoxon test). During the same period, mean graft blood flow increased in iloprost-treated patients by 74.5% compared with controls in whom there was a 6% increase in flow (p < 0.001). Primary cumulative patencies at 1 month were significantly higher in iloprost-treated grafts, 98% compared to 83% for controls (p < 0.05, log-rank test). Cumulative primary patencies at 1 year and secondary patencies at 1 month and 1 year were also greater in the iloprost-treated group (67%, 98%, and 87.6%, respectively) compared to controls (65%, 86%, and 79.3%, respectively), but these did not achieve statistical significance. A single bolus infusion of iloprost has prolonged beneficial effects on graft blood flow and peripheral resistance during femorodistal reconstruction. This is reflected by improved early primary graft patencies.(ABSTRACT TRUNCATED AT 250 WORDS)

Reperfusion plasma contains a neutrophil activator

Aortic aneurysm repair produces inflammatory mediators, neutrophil activation, and remote organ injury. Reperfusion plasma from these patients produces microvascular injury in an ex vivo chemotactic model. This study investigates the mechanism of this injury. Vena caval blood was obtained before and 15 minutes after aortic clamp removal (n = 16) or at laparotomy (n = 10). Plasma or saline solution was introduced into unit dose chambers fixed atop dermabrasions on the back of depilated anesthetized rabbits. Animals were treated with intravenous saline solution (n = 4); made neutropenic with nitrogen mustard (n = 4); pretreated with the xanthine oxidase inhibitor allopurinol (n = 4); or cotreated intravenously with the free radical scavengers superoxide dismutase (SOD) and catalase (n = 4). Three hours later neutrophil counts (polymorphonuclear cells [PMN]/mm3) and activity (free radical production by flow cytometry), protein leakage, and inflammatory mediators (thromboxane [TX] and leukotriene B4 [LTB4]) were measured. In contrast to control plasma in untreated rabbits, reperfusion plasma produced TX and LTB4 generation (1090 +/- 105 and 794 +/- 91 pg/ml, respectively, p < 0.01), PMN accumulation (1636 +/- 210/mm3, p < 0.01) and activation (276 +/- 31 mean fluorescent units), and microvascular permeability (554 +/- 90 micrograms/ml, p < 0.01). Neutropenia (3 +/- 1 PMN/mm3) and cotreatment with SOD and catalase abolished these responses, whereas pretreatment with allopurinol did not. Human reperfusion plasma contains a soluble factor that stimulates free radical generation by rabbit neutrophils to produce a microvascular injury characterized by de novo TX production, neutrophil accumulation and activation, and increased microvascular permeability to protein.

Iloprost reduces peripheral resistance during femoro-distal reconstruction

A randomised placebo-controlled trial was conducted to investigate the effect of iloprost, a stable prostacyclin mimetic, on peripheral resistance during femoro-distal bypass. Patients undergoing femoro-distal long saphenous vein bypass for critical ischaemia received 3000 ng of iloprost or placebo infused into the graft via an unligated side branch over 2 min. Graft blood flow and peripheral resistance were measured for 20 min, using an operative Doppler flowmeter (OpDop 130, SciMed, U.K.) and a pressure transducer to record graft pressure. Postoperatively, graft blood flow was assessed by daily duplex ultrasound for 7 days. Iloprost produced an immediate drop in peripheral resistance in all cases (n = 18) by a mean (range) of 40% (4-80%) compared with controls (n = 15) in whom there was a 5.3% (-8 to +36%) increase in resistance (p less than 0.01, Wilcoxon test). Decreased peripheral resistance in iloprost-treated patients persisted to 20 min. The largest decreases in peripheral resistance occurred in patients with the highest initial resistances (r = 0.56, p less than 0.02). Graft flow during the same period increased by 52% (-7 to 294%) compared with controls in whom there was a 6% (-17 to 26%) increase in flow, (p less than 0.01). Flow remained elevated by 53% over baseline values at 1 week post-infusion in the iloprost-treated group but this did not achieve statistical significance compared to controls in whom flow also increased by 13%. Iloprost produces an immediate decrease in peripheral resistance associated with a prolonged increase in graft blood flow. This may reduce graft failure in the early postoperative period.

Pharmacokinetics of intragraft iloprost infusion during femoro-crural reconstruction

Pharmacokinetics of a single intra-graft infusion of 3000ng iloprost during femoro-crural bypass surgery have been investigated. Plasma iloprost concentrations, biphasic half-lives, and total drug clearances were found to occur within ranges demonstrated for IV infusion dose regimens.