Effect of homocysteine-lowering treatment with folic acid plus vitamin B6 on progression of subclinical atherosclerosis: a randomised, placebo-controlled trial

BACKGROUND

A high plasma homocysteine concentration is associated with increased risk of atherothrombotic disease. We investigated the effects of homocysteine-lowering treatment (folic acid plus vitamin B6) on markers of subclinical atherosclerosis among healthy siblings of patients with premature atherothrombotic disease.

METHODS

We did a randomised, placebo-controlled trial among 158 healthy siblings of 167 patients with premature atherothrombotic disease. 80 were assigned placebo and 78 were assigned 5 mg folic acid and 250 mg vitamin B6 daily for 2 years. The primary endpoint was the development or progression of subclinical atherosclerosis as estimated from exercise electrocardiography, the ankle-brachial pressure index, and carotid and femoral ultrasonography.

FINDINGS

Ten participants in the treatment group, and 14 in the placebo group dropped out. Vitamin treatment, compared with placebo, was associated with a decrease in fasting homocysteine concentration (from 14.7 to 7.4 micromol/L vs from 14.7 to 12.0 micromol/L), and in postmethionine homocysteine concentration (from 64.9 to 34.9 micromol/L vs from 64.8 to 50.3 micromol/L). It was also associated with a decreased rate of abnormal exercise electrocardiography tests (odds ratio 0.40 [0.17-0.93]; p=0.035). There was no apparent effect of vitamin treatment on ankle-brachial pressure indices (0.87 [0.56-1.33]), or on carotid and peripheral-arterial outcome variables (1.02 [0.26-4.05] and 0.86 [0.47-1.59], respectively).

INTERPRETATION

Homocysteine-lowering treatment with folic acid plus vitamin B6 in healthy siblings of patients with premature atherothrombotic disease is associated with a decreased occurrence of abnormal exercise electrocardiography tests, which is consistent with a decreased risk of atherosclerotic coronary events.

Asymmetrical dimethylarginine (ADMA) in critically ill patients: high plasma ADMA concentration is an independent risk factor of ICU mortality

BACKGROUND AND AIMS

Accumulation of asymmetrical dimethylarginine (ADMA) has been linked to endothelial dysfunction, and is an important risk factor for cardiovascular disease. Its elimination from the body is dependent on urinary excretion and degradation by the enzyme dimethylarginine dimethylaminohydrolase. This enzyme is highly expressed in the liver, and in rat studies a high net hepatic uptake of asymmetrical dimethylarginine was found. In critically ill patients, we investigated the relation between indicators of renal and hepatic dysfunction and plasma ADMA concentration, and tested the association between ADMA concentration and outcome.

METHODS

We prospectively collected blood samples from a cross-section of critically ill patients (n=52) with clinical evidence of dysfunction of more than two organs. We identified correlates of plasma ADMA concentration with laboratory values, organ failures score and outcome by univariate and multiple regression analyses.

RESULTS

In critically ill patients, plasma ADMA concentration was independently related to the presence of hepatic failure (b=0.334, 95% CI: 0.207-0.461; P<0.001), and to lactic acid (b=0.395, 95% CI: 0.230-0.560; P<0.001) and bilirubin (b=0.121, 95% CI: 0.031-0.212; P=0.009) concentration as markers of hepatic function. Twenty-one (40%) patients deceased during their ICU stay. In a logistic regression model, plasma ADMA ranked as the first and strongest predictor for outcome, with a 17-fold (95% CI: 3-100) increased risk for ICU death in patients who were in the highest quartile for ADMA.

CONCLUSIONS

In critically ill patients, plasma ADMA concentration is a strong and independent risk factor for ICU mortality, and hepatic dysfunction is the most prominent determinant of ADMA concentration in this population.

Microvascular function relates to insulin sensitivity and blood pressure in normal subjects

BACKGROUND

A strong but presently unexplained inverse association between blood pressure and insulin sensitivity has been reported. Microvascular vasodilator capacity may be a common antecedent linking insulin sensitivity to blood pressure. To test this hypothesis, we studied 18 normotensive and glucose-tolerant subjects showing a wide range in insulin sensitivity as assessed with the hyperinsulinemic, euglycemic clamp technique.

METHODS AND RESULTS

Blood pressure was measured by 24-hour ambulatory blood pressure monitoring. Videomicroscopy was used to measure skin capillary density and capillary recruitment after arterial occlusion. Skin blood flow responses after iontophoresis of acetylcholine and sodium nitroprusside were evaluated by laser Doppler flowmetry. Insulin sensitivity correlated with 24-hour systolic blood pressure (24-hour SBP; r=-0.50, P<0.05). Capillary recruitment and acetylcholine-mediated vasodilatation were strongly and positively related to insulin sensitivity (r=0.84, P<0.001; r=0.78, P<0.001, respectively), and capillary recruitment was inversely related to 24-hour SBP (r=-0.53, P<0.05). Waist-to-hip ratio showed strong associations with insulin sensitivity, blood pressure, and the measures of microvascular function but did not confound the associations between these variables. Subsequent regression analysis showed that the association between insulin sensitivity and blood pressure was not independent of the estimates of microvascular function, and part of the variation in both blood pressure (R2=38%) and insulin sensitivity (R2=71%) could be explained by microvascular function.

CONCLUSIONS

Insulin sensitivity and blood pressure are associated well within the physiological range. Microvascular function strongly relates to both, consistent with a central role in linking these variables.

Hyperhomocysteinaemia and endothelial dysfunction in young patients with peripheral arterial occlusive disease

Hyperhomocysteinaemia, defined as an abnormally high plasma homocysteine concentration after an oral methionine load, is common in young (< or = 50 years) patients with peripheral arterial occlusive disease. It is thought to predispose to atherosclerosis by injuring the vascular endothelium. Treatment with pyridoxine and/or folic acid may lower plasma homocysteine levels. In mildly hyperhomocysteinaemic patients with peripheral arterial occlusive disease, we studied the effect of daily treatment with pyridoxine (250 mg) plus folic acid (5 mg) on homocysteine metabolism (i.e. plasma concentrations in the fasting state and after methionine loading, in 48 patients) and on endothelial function (in 18 patients). Endothelial function was estimated as the plasma concentrations of the endothelium-derived proteins, von Willebrand factor (vWF), thrombomodulin (TM), and tissue-type plasminogen activator (tPA). At baseline, fasting homocysteine levels were above normal in 24 of the 48 patients (50%); post-load levels, by definition, were above normal in 100% of patients. After 12 weeks of treatment, fasting and post-load levels were normal in 98 and 100% of patients, respectively. Endothelial function was assessed in 18 patients who completed 1 year of treatment. At baseline, median vWF (235%) and TM (57.1 ng mL-1) levels were above normal. At follow-up, vWF levels had decreased to 170% (P = 0.01) and TM levels had decreased to 49 ng mL-1 (P = 0.04). tPA levels were normal at baseline and did not change. Endothelial dysfunction is present in young patients with peripheral arterial occlusive disease and hyperhomocysteinaemia. Pyridoxine plus folic acid treatment normalizes homocysteine metabolism in virtually all patients, and appears to ameliorate endothelial dysfunction.

The liver is an important organ in the metabolism of asymmetrical dimethylarginine (ADMA)

BACKGROUND AND AIMS

Asymmetrical dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide (NO) synthase enzymes, whereas symmetrical dimethylarginine (SDMA) competes with arginine transport. Although both dimethylarginines may be important regulators of the arginine-NO pathway, their metabolism is largely unknown. Both dimethylarginines are removed from the body by urinary excretion. However, ADMA is also subject to enzymatic degradation by the enzyme dimethylarginine dimethylaminohydrolase (DDAH), which is highly expressed in the liver. To elucidate the role of the liver in the metabolism of ADMA, we aimed to investigate dimethylarginine handling of the liver in detail.

METHODS

Ten male Wistar rats were used for this study. Blood flow was measured using radiolabeled microspheres according to the reference sample method. Concentrations of dimethylarginines were measured by HPLC. The combination of arteriovenous concentration difference and organ blood flow allowed calculation of net organ fluxes and fractional extraction rates.

RESULTS

Both the liver (0.89+/-0.11) and the kidney (0.68+/-0.06) showed a high net uptake (nmol/100 g body weight (BW)/min) of ADMA, whereas a significant net uptake of SDMA was only observed in the kidney (0.34+/-0.04). For the liver, fractional extraction rates were 29.5% +/-3.0 for ADMA and 0.0%+/-3.7 for SDMA. Fractional extraction rates of ADMA and SDMA for the kidney were 36.0%+/-2.7 and 31.6%+/-3.8, respectively.

CONCLUSIONS

The liver plays an important role in the metabolism of ADMA by taking up large amounts of ADMA from the systemic circulation.

Long-term homocysteine-lowering treatment with folic acid plus pyridoxine is associated with decreased blood pressure but not with improved brachial artery endothelium-dependent vasodilation or carotid artery stiffness: a 2-year, randomized, placebo-controlled trial

Homocysteine is associated with atherothrombotic disease, which may be mediated through associations of homocysteine levels with blood pressure, endothelial function, or arterial stiffness. In a placebo-controlled, randomized clinical trial, we measured blood pressure, brachial artery endothelium-dependent vasodilation, and common carotid artery stiffness in 158 clinically healthy siblings of patients with premature atherothrombotic disease at baseline and after 1 and 2 years of homocysteine-lowering treatment with folic acid (5 mg) plus pyridoxine (250 mg). Intention-to-treat analyses limited to participants (n=130) who underwent at least 1 measurement after the baseline visit showed that compared with placebo, treatment with folic acid plus pyridoxine was associated with a 3.7-mm Hg (95% CI -6.8 to -0.6 mm Hg) lower systolic and a 1.9-mm Hg (95% CI -3.7 to -0.02 mm Hg) lower diastolic blood pressure over the 2-year trial period. Together with the decreased occurrence of abnormal exercise electrocardiography tests reported previously, our results support the hypothesis that homocysteine-lowering treatment with folic acid plus pyridoxine has beneficial vascular effects. Because no effects could be demonstrated on brachial artery endothelium-dependent vasodilation or on common carotid artery stiffness, the present study does not support the hypothesis that the cardiovascular effects of homocysteine are mediated through these factors, at least in clinically healthy individuals.

The relationship between visceral ischemia, proinflammatory cytokines, and organ injury in patients undergoing thoracoabdominal aortic aneurysm repair

OBJECTIVES

Plasma proinflammatory, anti-inflammatory cytokine, and soluble tumor necrosis factor (TNF) receptor concentrations were examined in hospitalized patients after abdominal and thoracoabdominal aortic aneurysm (TAAA) repair, with and without left atrial femoral bypass. Changes in plasma cytokine concentrations were related to the duration of visceral ischemia and the frequency rate of postoperative, single, or multiple system organ dysfunction (MSOD).

DESIGN

Prospective, observational study.

SETTING

Two academic referral centers in the United States and The Netherlands.

PATIENTS

We included 16 patients undergoing TAAA repair without left atrial femoral bypass, 12 patients undergoing TAAA repair with left atrial femoral bypass, and nine patients undergoing infrarenal aortic aneurysm repair.

MEASUREMENTS AND MAIN RESULTS

Timed, arterial blood sampling for proinflammatory and anti-inflammatory cytokine and soluble TNF receptor concentrations (p55 and p75), and prospective assessment of postoperative single and MSOD. Plasma appearance of TNF-alpha, interleukin (IL)-6, IL-8, and IL-10 peaked 1 to 4 hrs after TAAA repair, and concentrations were significantly elevated compared with infrarenal abdominal aortic aneurysm repair (p < .05). Left atrial femoral bypass significantly reduced the duration of visceral ischemia (p < .05) and the systemic TNF-alpha, p75, and IL-10 responses (p < .05). Plasma TNF-alpha concentrations >150 pg/mL were more common in patients with extended visceral ischemia times (>40 mins). Additionally, patients with early peak TNF-alpha concentrations >150 pg/mL and IL-6 levels >1,000 pg/mL developed MSOD more frequently than patients without these elevated plasma cytokine levels (both p < .05).

CONCLUSIONS

Thoracoabdominal aortic aneurysm repair results in the increased plasma appearance of TNF-alpha, IL-6, IL-8, IL-10, and shed TNF receptors. The frequency and magnitude of postoperative organ dysfunction after TAAA repair is associated with an increased concentration of the cytokines, TNF-alpha, and IL-6 and the increased plasma levels of these cytokines appear to require extended visceral ischemia times.

Plasma homocysteine and severity of atherosclerosis in young patients with lower-limb atherosclerotic disease

Elevated plasma homocysteine levels are recognized as an independent risk factor for atherosclerotic disease. It is not known (1) whether the severity of atherosclerotic disease is related to hyperhomocyst(e)inemia or (2) whether any such relation differs between fasting and post-methionine loading plasma homocysteine levels. Therefore, in 171 consecutive patients under 55 years of age with first symptoms of lower-limb disease, we examined the relation between severity of atherosclerosis and plasma homocysteine concentration. Severity of atherosclerotic disease was estimated from the prevalence of coronary artery disease and cerebrovascular disease and from the angiographic extent of lower-limb disease. Plasma homocysteine was measured after a period of fasting and in response to methionine loading (0.1 g/kg). In multivariate analysis, the prevalence of coronary artery disease plus cerebrovascular disease was related to both fasting and postmethionine homocysteine levels (odds ratio [OR] for the upper quartile versus the lower three quartiles, 2.8, 95% confidence interval [CI], 1.1 to 7.5; and OR 3.0, 95% CI, 1.1 to 7.8, respectively). The extent of lower-limb disease was weakly related to the fasting homocysteine level (partial correlation coefficient, .12; P = .17) and more strongly related to the postmethionine homocysteine level (partial correlation coefficient, .25; P = .003). These relations tended to be more pronounced in women than in men. They were independent of age, total serum cholesterol, blood pressure, and smoking habit. We concluded that the severity of atherosclerotic disease in young patients with lower-limb atherosclerotic disease is associated with high postmethionine and fasting homocysteine concentrations.

Combined vitamin B6 plus folic acid therapy in young patients with arteriosclerosis and hyperhomocysteinemia

PURPOSE

Hyperhomocysteinemia is associated with arteriosclerotic and thromboembolic events. The homocysteine-lowering effect of combined treatment with vitamin B6 plus folic acid has never been explored in a large group of patients with vascular disease. Therefore we studied the effects of at least 6 weeks treatment with these vitamins in 72 patients with cardiovascular disease and mild hyperhomocysteinemia (defined as an increase of the plasma homocysteine level after methionine loading greater than 97.5 percentile of age-matched control subjects but less than 200 mumol/L).

METHODS

The existence of mild hyperhomocysteinemia was investigated in 309 consecutive patients under 50 years of age with peripheral arterial occlusive disease, cerebral arterial occlusive disease, or coronary artery occlusive disease. All patients with an abnormal loading test result were treated with vitamin B6, 250 mg daily, plus folic acid, 5 mg daily. After 6 weeks of treatment a second methionine loading test was performed to assess the homocysteine-lowering effect.

RESULTS

Mild hyperhomocysteinemia was detected in 72 patients (23%), 33 (46%) of whom also had hyperhomocysteinemia when fasting. Treatment with vitamin B6 plus folic acid normalized the postload plasma homocysteine concentration in 66 of the 72 patients (92%), whereas fasting hyperhomocysteinemia was normalized in 30 of 33 (91%) patients. In six patients therapy failed to achieve normalization of the postload homocysteine levels. In three of these patients, the same treatment was continued for an additional 6 weeks, and in the remaining three patients betaine was added to the treatment regimen. After 6 weeks of additional treatment all six patients had normal postload plasma homocysteine concentrations.

CONCLUSION

The prevalence of mild hyperhomocysteinemia in young patients with arterial occlusive disease is high. Simple and inexpensive therapy with vitamin B6 plus folic acid will normalize homocysteine metabolism, as assessed by the homocysteine plasma level after methionine loading, in virtually all these patients.

Familial abdominal aortic aneurysm: a systematic review of a genetic background

BACKGROUND

Familial clustering of the abdominal aortic aneurysm (AAA) is clear, 12-19% of AAA patients have one or more first-degree relatives with an aneurysm and 4-19% is detected with ultrasound screening.

OBJECTIVES

To review the genetic background of AAA. DESIGN, METHODS AND MATERIALS: Computer searches of the MEDLINE, EMBASE, SUMsearch database and the Cochrane Library and searched reference lists of English language articles concerning the genetics of AAA, candidate gene approach and linkage analysis.

RESULTS

Brothers of AAA patients are at high risk to develop an AAA. The candidate gene approach was performed to detect defects in one of the components of the connective tissue, i.e. type I and III collagen, elastin and fibrillin, the inflammatory cell-derived matrix metalloproteinase, there inhibitors, auto-immune components and components related to atherosclerosis.

CONCLUSION

These studies give us insight in the pathology but do not lead to the specific genetic factor(s) responsible for (familial) AAA. Considering the supposed autosomal dominant inheritance, a gene mutation in one of the structural proteins of the connective tissue is expected. In the future, linkage analysis may resolve the genetic background of AAA.

The inflammatory response to vascular surgery-associated ischaemia and reperfusion in man: effect on postoperative pulmonary function

OBJECTIVES

To characterise the inflammatory response to vascular surgery and ischaemia/reperfusion (I/R) in man, regarding release of inflammatory mediators, recruitment and activation of neutrophils, and their relation to postoperative pulmonary function.

DESIGN

Prospective cohort study.

MATERIALS AND METHODS

Circulating neutrophil counts and plasma levels of elastase-alpha 1-antitrypsin (AT), a neutrophil degranulation product, were measured before and approx. 2.5 h (group 1, n = 19) after elective abdominal aortic surgery, and approx. 2.9 h after elective peripheral vascular surgery (group 2, n = 6), together with concentrations of neutrophil agonists, including activated complement (C3a), secretory phospholipase A2 (sPLA2), tumor necrosis factor (TNF-alpha), interleukin (IL)-6, IL-8 and granulocyte colony-stimulating factor (G-CSF). At the time of blood sampling, respiratory variables allowing computation of the lung injury score (LIS) were obtained in patients admitted after surgery in the intensive care unit (ICU), i.e. all group 1 patients and one group 2 patient.

RESULTS

Median (range) neutrophil counts rose by 80% (-28-208) and 90% (10-147) in groups 1 and 2, respectively (n.s. between groups). The increase (p < 0.05) in elastase-alpha 1-AT level was 121% (-5-439) in group 1 and 82% (18-792) in group 2 (n.s. between groups). There was a rise (p < 0.05) in C3a level by 93% (-42-751) and of sPLA2 level by 68% (-40-1400) after surgery for the groups together (n.s. between groups), and the rise of the elastase-alpha 1-AT related to that of the C3a levels. IL-6 and G-CSF concentrations increased more in group 1 than 2. The IL-8 concentration increased in group 1 only, and TNF-alpha was unchanged in all groups. In ICU patients, the LIS related to the postoperative rise in IL-6 level only, even though the rise in plasma concentrations of cytokines interrelated. No patient developed ARDS and all survived.

CONCLUSIONS

Vascular surgery and I/R in man activates complement, releases cytokines (except for TNF-alpha), and induces neutrophil recruitment and degranulation, which may primarily depend on complement activation. In contrast to the latter, the release of cytokines may depend on the extent of I/R and may contribute to transient pulmonary dysfunction after extensive I/R.

Retroperitoneal endoscopic ligation of lumbar and inferior mesenteric arteries as a treatment of persistent endoleak after endoluminal aortic aneurysm repair

A 74-year-old man receiving long-term anticoagulation therapy for intermittent atrial fibrillation had a type II endoleak after endovascular abdominal aortic aneurysm repair. During an 8-month follow-up, the endoleak persisted, and the aneurysm failed to decrease in diameter. By means of a left flank retroperitoneal endoscopic surgical approach, the aneurysm was dissected free, and the lumbar arteries emanating from the aneurysm, as well as the inferior mesenteric artery, were ligated with titanium clips. A postoperative spiral computed tomography scan depicted one pair of unclipped lumbar arteries just proximal to the aortic bifurcation. After immediate reoperation with the same approach, complete thrombosis of the aneurysm sac was radiographically confirmed.

Transient increase in interleukin-8 and pulmonary microvascular permeability following aortic surgery

Aortic surgery results in ischemia/reperfusion of the lower body. This may liberate inflammatory mediators that activate neutrophils, and may result in lung microvascular changes with increased permeability and respiratory failure. We studied circulating inflammatory mediators and the pulmonary leak index (PLI) of 67Ga, a measure of transvascular transferrin transport and permeability, in patients scheduled for elective aortic and peripheral vascular surgery, before and after surgery. Aortic surgery patients in Groups 1 (n = 10) and 2 (n = 7) were studied before and at a median of 2.5 and 21.0 h after surgery, respectively. A control Group 3 (n = 6) was studied before and at a median of 2.9 h after peripheral vascular surgery. The PLI (median) increased from a median of 9.1 (range, 6.6 to 14.7) before to a median of 23.4 (range, 18.7 to 86.4) x 10(-3)/min after surgery in Group 1 but not in the other groups (p < 0.001). The postoperative increase in circulating neutrophils and elastase-alpha 1-antitrypsin, a marker of neutrophil activation, was similar among the groups. Plasma levels of activated complement 3a and tumor necrosis factor (TNF-alpha) did not change in any of the groups. In contrast, plasma levels of interleukin-8 (IL-8) increased in Group 1 from < 3 (range, < 3 to 37) before to 324 (range, 36 to 868) pg/ml after surgery, but did not change in the other groups (p < 0.005). The decrease in plasma levels of angiotensin converting enzyme (ACE) was greater in Group 1 than in the other groups (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Fish oil supplementation in patients with stable claudication

Increased blood viscosity occurs in patients with claudication. This increase in viscosity, which is mainly due to elevated fibrinogen levels and a decreased red cell deformability, adversely influences blood flow. In addition to a positive effect on blood pressure, blood lipids, and platelet responsiveness, fish oil may improve blood flow due to a favorable influence on hemorrheology. In a prospective, randomized, double-blind study, we evaluated the effect of six capsules of fish oil (1.8 g eicosapentaenoic acid and 1.2 g docosahexaenoic acid) versus six capsules of corn oil (3 g linoleic acid), administered for 4 months, on walking distances, pressure indices during rest and after exercise, blood pressure, red cell deformability, fibrinogen, and lipid levels in 32 patients with stable claudication. No significant changes in walking distances and pressure indices during rest and after exercise occurred, despite a significant increase in red cell deformability in the fish oil group. Fibrinogen levels did not change in either group. In the fish oil group, a favorable change in blood lipids was noted; high-density cholesterol increased and triglycerides decreased. Mean arterial blood pressure declined to a similar extent in both groups. Thus, short-term supplementation with fish oil does not lead to clinically significant improvement of symptoms in patients with stable claudication. This suggests that red cell deformability is of minor importance in the arterial blood flow in the legs of these patients.

Genome-wide linkage in three Dutch families maps a locus for abdominal aortic aneurysms to chromosome 19q13.3

OBJECTIVES

Elucidation of the genetic background of familial abdominal aortic aneurysm (AAA) suggests a genetic etiology.

METHODS AND RESULTS

We carried out a genome-wide scan in three Dutch families with four or five affected siblings. Suggestive loci were further studied by subsequent fine mapping of the locus performed in 101 affected sib-pairs. The genome-wide scan was performed with 400 DNA markers and results were given as non-parametric, multipoint linkage scores (NPL). We observed a suggestive linkage for AAA (NPL score 3.25 at D19S902, 72.72 cM) on chromosome 19q in the three families. After fine mapping on chromosome 19, the NPL score became nominal in the 101 affected sib-pairs. A separate analysis of the three families with fine mapping revealed a peak with significant evidence for linkage (NPL score 3.95 at D19S904, 78.08 cM) on chromosome 19q. This peak was situated to the right compared to the region found in a previously published article for familial AAA on chromosome 19q.

CONCLUSIONS

Our results identified a candidate locus in three Dutch families with AAA at chromosome 19q13.3. Separate analysis of these three families provides evidence for genetic heterogeneity.

Hyperhomocysteinaemia; with reference to its neuroradiological aspects

Severe or even mild hyperhomocysteinaemia can cause a wide range of neurological problems. In recent years its vascular complications, including cerebral stroke, in children and young adults have gained special interest, because hyperhomocysteinaemia is treatable and recurrence of vascular incidents may be preventable. Current knowledge about biochemical mechanisms leading to hyperhomocysteinaemia, the pathogenesis of vascular pathology and neurological disfunction, and the various patterns of cerebral damage are reviewed. The significance of MRI in diagnosis, follow-up and research on hyperhomocysteinaemia is discussed.

Normohomocysteinaemia and vitamin-treated hyperhomocysteinaemia are associated with similar risks of cardiovascular events in patients with premature peripheral arterial occlusive disease. A prospective cohort study

OBJECTIVES

Mild hyperhomocysteinaemia (HHC), fasting or after methionine loading, is associated with an increased risk and severity of atherosclerotic vascular disease. Post-methionine and fasting HHC are responsive to treatment with vitamin B, and folic acid. We performed a prospective cohort study amongst normohomocysteinaemic and vitamin-treated (vitamin B6, 250 mg plus folic acid, 5 mg daily) hyperhomocysteinaemic patients with premature peripheral arterial occlusive disease and assessed the incidence of cardiovascular events.

DESIGN

We studied 273 consecutive patients with clinically manifest peripheral arterial occlusive disease with onset before the age of 56, 79 (28.9%) of whom had postmethionine HHC. Follow-up was obtained in 232 (85'%o) patients. At baseline, 70 (30')/) were hyperhomocysteinaemic after methionine loading and started treatment with vitamin B, and folic acid; 162 (70%) were normohomocysteinaemic (reference group).

RESULTS

During the follow-up period (median 20, range 1-63 months), 48 (29.6%) and 23 (32.9%) of the normo- and the hyperhomocysteinaemic patients, respectively, had a new cardiovascular event. Most (75%) involved the peripheral arterial system. The crude incidence rate for any cardiovascular event was 0.16 (95% CI, 0.12-0.21) per person per year in the normohomocysteinaemic and 0.16 (95% CI, 0.09-0.22) per person per year in the hyperhomocysteinaemic group. Multivariate Cox regression analyses showed that higher plasma homocysteine levels were associated with an increased risk of new cardiovascular events in the normohomocysteinaemic patients (relative risk [RR] per 1 micromol L(-1), 1.17 [CI, 1.05-1.30] for fasting and 1.06 [CI, 1.01-1.12] for postmethionine levels), but not in the hyperhomocysteinaemic (vitamin-treated) patients. The adjusted RR for new cardiovascular events in the hyper- as compared to the normohomocysteinaemic patients was 0.76 (CI, 0.33-1.74).

CONCLUSIONS

These data are consistent with a protective effect of treatment with vitamin B6 and folic acid in patients with premature peripheral arterial occlusive disease and postmethionine HHC. Double-blind randomized trials are necessary to confirm this.

Increased gastric PCO2 during exercise is indicative of gastric ischaemia: a tonometric study

BACKGROUND

Diagnosis of gastric ischaemia is difficult and angiography is an invasive procedure. Angiographic findings may not correlate with clinical importance.

AIMS

To investigate whether tonometric measurement of intragastric PCO2 during exercise can be used to detect clinically important gastric ischaemia.

METHODS

Fourteen patients with unexplained abdominal pain or weight loss were studied. Splanchnic angiography served as the gold standard. Three patients were studied again after a revascularisation procedure. Gastric PCO2 was measured from a nasogastric tonometer, with 10 minute dwell times, and after acid suppression. Gastric and capillary PCO2 were measured before, during, and after submaximal exercise of 10 minutes duration.

RESULTS

Seven patients had normal angiograms; seven had more than 50% stenosis in the coeliac (n=7) or superior mesenteric artery (n=4). Normal subjects showed no changes in tonometry. In patients with stenoses, the median intragastric PCO2 (PiCO2) at rest was 5.2 kPa (range 4.8-11.2) and rose to 6.4 kPa (range 5.7-15.7) at peak exercise; the median intragastric blood PCO2 gradient increased from 0.0 kPa (range -0.8 to 5.9) to 1.7 kPa (range 0.9 to 10.3; p<0.01). Only two subjects had abnormal tonometry at rest; all had supernormal values at peak exercise. The PCO2 gradient correlated with clinical and gastroscopic severity; in patients reexamined after revascularisation (n=3), exercise tonometry returned to normal.

CONCLUSION

Gastric tonometry during exercise is a promising non-invasive tool for diagnosing and grading gastrointestinal ischaemia and evaluating the results of revascularisation surgery for symptomatic gastric ischaemia.

Robot-assisted laparoscopic surgery of the infrarenal aorta

BACKGROUND

Recently introduced robot-assisted laparoscopic surgery (RALS) facilitates endoscopic surgical manipulation and thereby reduces the learning curve for (advanced) laparoscopic surgery. We present our learning curve with RALS for aortobifemoral bypass grafting as a treatment for aortoiliac occlusive disease.

METHODS

Between February 2002 and May 2005, 17 patients were treated in our institution with robot-assisted laparoscopic aorto-bifemoral bypasses. Dissection was performed laparoscopically and the robot was used to make the aortic anastomosis. Operative time, clamping time, and anastomosis time, as well as blood loss and hospital stay, were used as parameters to evaluate the results and to compare the first eight (group 1) and the last nine patients (group2).

RESULTS

Total median operative, clamping, and anastomosis times were 365 min (range: 225-589 min), 86 min (range: 25-205 min), and 41 min (range: 22-110 min), respectively. Total median blood loss was 1,000 ml (range: 100-5,800 ml). Median hospital stay was 4 days (range: 3-57 days). In this series 16/18 anastomoses were completed with the use of the robotic system. Three patients were converted (two in group 1, one in group 2), and one patient died postoperatively (group 1). Median clamping and anastomosis times were significantly different between groups 1 and 2 (111 min [range: 85-205 min] versus 57.5 min [range: 25-130 min], p < 0.01 and 74 min [range: 40-110 min] versus 36 min [range: 22-69 min], p < 0.01, respectively) Total operative time, blood loss, and hospital stay showed no significant difference between groups 1 and 2.

CONCLUSIONS

Robot-assisted aortic anastomosis was shown to have a steep learning curve with considerable reduction of clamping and anastomosis times. However, due to a longer learning curve for laparoscopic dissection of the abdominal aorta, operation times were not significantly shortened. Even with robotic assistance, laparoscopic aortoiliac surgery remains a complex procedure.

Vascular injury from external fixation: case reports

The incidence of vascular injury from external fixation of fractures was studied retrospectively in two surgical departments during the period 1985-1990. A total of 1231 fractures of the lower limb were treated. External fixation was used in the initial stabilization of 28 femoral and 93 tibial fractures. In this series of 121 fractures four iatrogenic vascular injuries were seen: two arterial thromboses with distal ischemia and two incidents of the formation of a false aneurysm with bleeding along a pin. The diagnosis was made by angiography. Surgical intervention was necessary in all four cases. In one patient the injury resulted in amputation of the distal portion of the foot.

Acute lung injury after aortic surgery: the relation between lung and leg microvascular permeability to 111indium-labelled transferrin and circulating mediators

BACKGROUND

Aortic surgery is a risk factor for acute lung injury and this may relate to ischaemia/reperfusion (I/R) of the lower body and release of inflammatory mediators. The aim of this study was to define the changes in microvascular protein permeability and circulating inflammatory mediators after aortic surgery.

METHODS

In 11 consecutive patients who underwent elective aortic surgery microvascular permeability in lung and leg was measured before and a median of 2.8 hours after completion of surgery using 111indium (In)-labelled transferrin and 99mtechnetium (Tc)-labelled red blood cells, yielding a protein leak index (PLI) that is specific for protein permeability. Circulating leucocyte counts and levels of inflammatory mediators were determined.

RESULTS

In the lung the PLI rose from a median of 0.6 (range -0.5 to 2.2) x 10(-3)/min before surgery to 5.4 (-2.3 to 33.5) x 10(-3)/min after surgery, and in the leg from 0.3 (-1.6 to 1.7) x 10(-3)/min to 5.0 (1.0 to 27.8) x 10(-3)/min. The increase in PLI in the lung was related to that in the leg. Levels of activated complement C3a and tumour necrosis factor-alpha did not change, but levels of interleukin (IL)-6, IL-8 and elastase-alpha 1-antitrypsin increased. After surgery there was slight neutrophilia and the leucocyte counts were inversely related to the IL-8 level. The rise in lung but not in leg PLI was greatest in patients with the highest IL-8 levels and the lowest leucocyte counts.

CONCLUSIONS

Early after aortic surgery microvascular protein permeability increases in the leg and lung. Leg I/R injury may result in neutrophil activation and release of IL-8, which may induce neutrophil sequestration and subsequently increased pulmonary microvascular permeability. These findings may help to explain the occurrence of acute lung injury after I/R in man.

Robot-assisted Laparoscopic Aortobifemoral Bypass for Aortoiliac Occlusive Disease: Early Clinical Experience

BACKGROUND

Robotic technology may facilitate laparoscopic aortic reconstruction. We present our early clinical experience with laparoscopic aortobifemoral bypass, aided by two different robotic surgical systems.

METHODS

Between February 2002 and April 2004, we performed eight robot-assisted laparoscopic aorto-bifemoral bypasses for aortoiliac occlusive disease. All patients were male; median age was 55 years (range: 36-64). Dissection was performed laparoscopically and the robotic system was used to construct the aortic anastomosis.

RESULTS

A robot-assisted anastomosis was successfully performed in seven patients. Median operative time was 405 min (range: 260-589), with a median clamp-time of 111 min (range: 85-205). Median blood loss was 900 ml (range: 200-5800). Median anastomosis time was 74 min (range 40-110). In two patients conversion was necessary, one due to bleeding of an earlier clipped lumbar artery after completion of the anastomosis, the other because of difficulties with the laparoscopic exposure of the aorta. On post-operative day 3 one patient died unexpectedly as a result of a massive myocardial infarction. Median hospital stay was 7.5 days (range: 3-57).

CONCLUSION

Our initial experience with robotic assisted laparoscopic surgery (RALS) shows it is a feasible technique for aortoiliac bypass surgery. However, laparoscopic aortoiliac surgery demands considerable experience and operative times need to be reduced before this technique can be widely implemented.

Foot debridement: anatomic knowledge is mandatory

The foot is well adapted for its purpose. This is reflected by its special anatomical architecture, having a thickened epidermis, subcutaneous fatty pads and muscles arranged in compartments. In diabetic patients, metabolic changes and foot deformity can lead to high pressure zones resulting in a foot ulcer. If an ulcer gets infected, the oedema aggravates the underlying muscle compartment pressure, even leading to muscle necrosis. This explains why foot ulcers can lead to extensive tissue necrosis. For debridement, sound anatomical knowledge of the foot anatomy is mandatory.

Endoscopic versus transaxillary thoracic sympathectomy for primary axillary and palmar hyperhidrosis and/or facial blushing: 5-year-experience

Thoracic sympathectomy is effective in the permanent cure of primary axillary and palmar hyperhidrosis and facial blushing, which can be so troublesome for patients that their social and professional relations can be affected. Between October 1988 and April 1994, a total of 50 thoracic sympathectomies (10 surgical and 40 endoscopic) were performed on 5 and 23 patients, respectively. The operations were performed unilaterally, followed by the contralateral intervention after a period of 6-8 weeks. The thoracic ganglia T2-T5 were resected for hyperhidrosis. If the patient suffered from blushing, the lower 1/3 of the stellate ganglion was also resected. Postoperatively, all the operated limbs were warm and dry. In the group of patients who were operated bilaterally, only one had persistent facial blushing. The efficacy for blushing in this series was therefore 93.3%. The late relapse rate of sympathetic activity was 14.3%. Compensatory sweating was seen in 67%, gustatory sweating in 37.5% and phantom sweating in 29% of the patients. None of them considered these side effects to be troublesome. Although there is no difference between transaxillary thoracic sympathectomy and the endoscopic intervention in terms of efficacy, the latter is associated with less postoperative pain, shorter hospital stay and a rapid recovery. The thoracic sympathectomy is the treatment of choice for primary hyperhidrosis and excessive facial blushing.