Clinical and microcirculatory effects of transcutaneous CO2 therapy in intermittent claudication. Randomized double-blind clinical trial with a parallel design.

BACKGROUND: This randomized, double blind trial determined the short and long-term clinical and hemodynamic vasodilator effects induced by percutaneous applications of natural CO2 gas in patients with moderate Fontaine stage II. PATIENTS AND METHODS: 62 patients with intermittent claudication (100-500 meters) were randomized to 18 consecutive days of CO2 treatment or placebo (air). The gas fluids were applied at a constant temperature of 30 degrees C on pre-humidified skin. The effects of the treatment were evaluated by total distance walked (primary criterion) and hemodynamic and microcirculatory findings. Patients also answered a quality of life questionnaire. RESULTS: The Strandness test showed a significant increase in total distance walked (+ 131 meters, 66%; p = 0.001) and pain-free distance (+ 81 meters, 73%; p = 0.02) after 18 days of CO2 treatment. The improvement was maintained 3 and 12 months later. The systolic pressure index (ABI) increased by 37% (p = 0.001) 1 minute after treadmill walking and ABI recovery time decreased significantly by 38% (p = 0.002). Microcirculatory findings showed an increase in systolic pressure of the great toe (13%; p < 0.0001), in baseline pO2 (20%; p = 0.01) and in vasomotion (78%; p = 0.001) in the treatment group. The improvement in total walking distance was correlated with the increase in ABI and peripheral cutaneous oxygenation. Patients' subjective assessments corroborated the benefits. No significant change was observed in the placebo group. CONCLUSIONS: This study demonstrates that 18 consecutive days of percutaneous CO2 treatment significantly increases walking distance in patients with moderate intermittent claudication. This effect, which was associated with an increase in peripheral systolic pressure and pO2, is evidence of a better ability to withstand effort.

Microcirculatory and clinical effects of serial percutaneous application of carbon dioxide in primary and secondary Raynaud's phenomenon.

BACKGROUND: A randomized double-blind monocentric trial was conducted at the spa of Royat, France, in patients with mild Raynaud's phenomenon (one or two attacks a day during the autumn and winter months). Hemodynamic changes were quantified by laser Doppler flow (LDF) and computerized chronothermometric test (CT) during local application of CO2 and compared with the usual clinical parameters. PATIENTS AND METHODS: Patients were randomized to 18 days of CO2 (group 1) or 9 days of air + 9 days of CO2 (group 2). The gas was applied at a constant temperature to previously humidified skin on the forearm. Effects of the active treatment were measured by LDF and continuing benefits by computerized chronothermometric test (CT test). Clinical assessment was made on four occasions (before, in the middle and at the end of treatment, and three months afterwards) on the basis of the number of daily attacks and the duration and severity of the attacks. RESULTS: LDF showed a significant increase in digital blood flow (+ 41%) and in vasomotion (+ 42%) during CO2 treatment but no change on placebo treatment. CT test showed a comparable response to cold in the two groups during treatment. Three months later, however, warming time was significantly decreased (by 7 minutes: 25%) and warming rate increased (+ 22.4%) in group 1 (intergroup difference: p = 0.02). There was no difference between groups in the weekly number of attacks during treatment periods. In contrast there was a moderate increase in both groups in the winter months. There was no increase in the severity of the attacks nor in their duration. CONCLUSION: In this clinical trial, LDF evidenced positive effects of percutaneous application of natural CO2 gas on vasomotricity and vasomotion while CT test showed that patients who had received 18 days of CO2 adapted more easily to exposure to cold. Clinical improvement seems to be masked by winter weather conditions.

Biomonitoring of genotoxic risk in workers in a rubber factory: comparison of the Comet assay with cytogenetic methods and immunology.

Several substances used in rubber processing are known to be genotoxic. Workers in a rubber tyre factory, exposed to a broad spectrum of contaminants such as benzo[a]pyrene, benzo-fluoranthene, naphthalene, acetonaphthene, alkenes and 1,3-butadiene have been regularly examined for several years: chromosomal aberrations in lymphocytes, mutagenicity of urine (by use of the Ames test) and various parameters of blood and urine were assessed. An elevated level of mercapturic acid derivatives was found in the urine of employees, which is indicative of environmental exposure to toxicants with alkylating activity. We have now extended this study by examining genotoxicity with the modified Comet assay in parallel with chromosomal aberrations and micronucleus formation as well as immunological endpoints. Twenty-nine exposed workers from this factory were compared with 22 non-exposed administrative staff working in the same factory, as well as with 22 laboratory workers. The absolute numbers of peripheral leukocytes were significantly higher in the exposed group than in either of the control groups (p < 0.001). The erythrocyte mean cell volume was significantly higher in exposed workers in comparison with laboratory controls (p < 0.05). Percentages of lymphocytes, polymorphonuclear leukocytes, monocytes and eosinophils were not altered. The proliferative response of T- and B-cells to mitogen treatment when calculated per number of lymphocytes and adjusted for smoking, age and years of exposure did not differ between exposed and control groups. Endogenous strand breaks (including alkali-labile sites) and altered bases (formamidopyrimidine glycosylase- and endonuclease III-sensitive sites) were measured by the Comet assay in lymphocyte DNA. Exposed workers had significantly elevated levels of DNA breaks compared with office workers (p < 0.00001) or with laboratory controls (p < 0.00001). Micronuclei occurred at significantly higher frequencies in the exposed group than in controls (p < 0.00001), though the frequencies were all within the normal range. Significant correlations were seen between individual values of strand breaks, micronuclei and chromatid/chromosome breaks and certain immunological parameters.

DNA damage in diabetes: correlation with a clinical marker.

Levels of DNA damage in groups of 10 patients with insulin-dependent diabetes mellitus and 10 matched controls were compared using the comet assay; DNA strand breaks, oxidized pyrimidines (endonuclease III-sensitive sites) and altered purines (sites sensitive to formamidopyrimidine glycosylase) were measured. Mean values of strand breaks and oxidized pyrimidines were significantly higher in diabetics. Strand breaks correlated with body mass index in the diabetic group. A strong correlation was seen between formamidopyrimidine glycosylase-sensitive sites and serum glucose concentrations. When three patients with normal glucose levels were excluded from the statistical analysis, the mean value of formamidopyrimidine glycosylase-sensitive sites was very significantly elevated compared with normal. DNA damage in lymphocytes is thus a useful marker of oxidative stress, and in particular formamidopyrimidine glycosylase-sensitive sites seem to represent changes specifically related to hyperglycemia.

Ciprofibrate treatment in patients with atherogenic lipoprotein phenotype: effects on HDL quality, LDL susceptibility to oxidation and DNA damage.

OBJECTIVES: This study was conducted to examine a complex effect of ciprofibrate therapy in patients with atherogenic lipoprotein phenotype. METHODS: Effects of ciprofibrate were studied on HDL subpopulations, HDL ability to esterify cholesterol (FER(HDL)), susceptibility of LDL to oxidation as well as on in vivo oxidative DNA damage in peripheral lymphocytes, measured as strand breaks (SBs) by the comet assay. RESULTS: Ciprofibrate treatment significantly decreased total cholesterol, and triglycerides, and increased HDL-cholesterol. The FER(HDL) showed a significant reduction (29.5+/-7.4 to 23+/-7.5% x h(-1), P=0.0001). The relative concentrations of HDL subclasses did not differ between baseline and after treatment. Ciprofibrate induced a significant increase in LDL oxidation lag time (93+/-7 to 102=11 min, P=0.02) and a decrease in DNA strand breaks (34.0+/-16.2 to 17.8+/-7.5, P=0.02). A significant correlation between maximal rate of diene production and strand breaks was found (r=0.55, P=0.01). These findings may be explained by an improvement of LDL resistance to oxidation, resulting in a decrease in oxidatively modified LDL's cytotoxic effect. CONCLUSION: Ciprofibrate treatment favourably affected the quality of plasma HDL, probably by the improvement of triglyceride rich lipoprotein metabolism and/or LDL subpopulation profile, increased LDL resistance to oxidation, and decreased the level of DNA damage in peripheral lymphocytes.

[Thermal treatment in arterial diseases: an expensive placebo or an effective therapy?]. / Le traitement thermal des maladies artérielles: un placebo coûteux ou une thérapeutique à part entière?

Each year, Royat (Auvergne) receives about 20,000 patients (80 per cent with intermittent claudication), treated by thermal gas (99.5 per cent of CO2). CO2 therapy is dispensed with thermal water or with dry gas (general or local immersion and local subcutaneous injections of gas) during 3 weeks. Local vasodilator effects of CO2 have been demonstrated with several methods in Royat. Physiological and therapeutic effects of thermal CO2 therapy, also used in Germany and Central Europe, were precisely reported during the Consensus Congress of Fribourg in Brisgau (1989); more particularly, this treatment seems provide a reduced ability of haemoglobin to fix oxygen, and therefore a release of oxygen within the cells. Patients with peripheral arterial disease (stage 2) have a walking distance increased and post-exercise ankles' pressures improved after a thermal course of treatment in Royat, while a control group has no significant changes. The discussion will concern also the socio-economic aspects of thermal treatment of arterial diseases.

Laser Doppler flowmetry, transcutaneous oxygen pressure and thermal clearance in patients with vascular intermittent claudication.

In the present study, heat thermal clearance (HTC) was compared to laser Doppler flowmetry (LDF) and transcutaneous oxygen pressure (tcPO2), measured on the forefoot of 17 patients with vascular intermittent claudication and 10 controls in various positions at rest and after a treadmill exercise test. The mean ankle brachial systolic pressure ratio (ABSP) of the patients, measured using ultrasonic Doppler velocimetry, was 0.53 +/- 0.05. Their walking distance was 480 +/- 100 meters, the treadmill exercise being stopped as soon as pain sensation. No statistically significant difference was found between patients and controls for HTC, LDF, tc P02, forefoot and ankle skin temperatures. Statistically significant differences between patients and controls occurred in the sitting position for tcPO2, in standing position for HTC and after treadmill exercise for tcPO2 and LDF. When assuming the sitting position HTC did not vary significantly in patients and decreased in controls, LDF decreased and tcPO2 increased in both groups. After treadmill exercise, HTC in patients did not vary compared to supine values and HTC decreased in controls, tcPO2 remained unchanged in controls and decreased in patients, LDF increased in controls and decreased in patients. No significant correlations were found between the different techniques measured at rest in patients and controls. However in patients, after the treadmill test, LDF correlated with the walking distance (r = 0.667) and with ABSP (r = 0.641), HTC inversely correlated with the walking distance (r = -0.680) and ABSP (r = -0.577). Laser Doppler, tcPO2 and HTC are useful as tools to understand the alterations of cutaneous microcirculation of the lower limbs in patients with V.I.C.. However their results need to be interpreted with caution because these methods do not measure directly blood flow.

[Silent ischemic heart diseases in patients with peripheral arterial diseases. Screening and 5-year prognosis in a population of 418 patients]. / Les cardiopathies ischémiques silencieuses chez l'artéritique. Dépistage et pronostic à 5 ans dans une population de 418 patients.

Silent ischaemic heart disease was looked for by exercise stress testing in 418 patients with chronic obliterative arterial disease of the lower limbs with no clinical or electrocardiographic signs of myocardial ischaemia. In the initial work-up, 6.2% of patients had a positive exercise test and the results were suspect in 9.2% of patients. These patients were followed up for 5 years. There were 42 deaths (10%). The cause of death was cardiovascular in 53.7% of cases (myocardial infarction 40.4%) and malignant disease in 35.7%. During the 5 year follow-up, ischaemic heart disease present as angina pectoris or myocardial infarction in 115 cases (27.5%). Patients who had a positive exercise stress test initially had a particularly high death rate (23%) and developed clinical signs of coronary insufficiency in 57.5% of cases. On the other hand, the peripheral vascular complications were relatively rare in this series: cerebrovascular accidents: 1.4%; retinal vascular accident: 1.1%; carotid surgery: 1.6%; lower limb amputation: 1.9%; lower limb vascular surgery: 17.7%. Silent ischaemic heart disease is very prevalent in patients with obliterative arterial disease of the lower limbs and is a main vital prognostic factor in these patients. These results confirm the need for a complete cardiovascular check-up in all patients with peripheral arterial disease.

Comparison of standard one-minute treadmill exercise and strandness test (absolute walking distance) in relation to site of lesion, walking distance, and diastolic blood flow velocity (Doppler curves).

In 215 outpatients suffering from occlusive arterial disease of the lower limbs the authors compared the decrease in the ratio of ankle systolic pressure to brachial systolic pressure according to whether the treadmill exercise was limited to one minute or extended until pain forced the patient to stop. After a one-minute walk the pressure index always decreased significantly, especially when walking was restricted. The decrease in the pressure index was generally greater when the exercise was continued until the absolute walking distance, and the recovery time was usually twice as long. The fall in the pressure index was significantly greater for patients with single and multiple iliac stenoses than for those with stenoses at lower levels. In patients having a diastolic blood flow velocity on Doppler curves at rest, not modified by walking, a maximum drop in peripheral pressure was recorded after walking for one minute. In this instance there was no intensification of the decrease in peripheral pressure, unlike in patients without a diastolic blood flow velocity at rest. This one-minute test is not a maximal hemodynamic response, but it is sufficient for the appreciation of ischemia during exercise, according to the different parameters measured.

Calf sweat lactate in peripheral arterial occlusive disease.

The energy metabolism of sweat glands was studied to evaluate the reduction in oxygen delivery in the tissue of patients with peripheral arterial occlusive disease. We compared lactate concentration in pilocarpine-iontophoresis sweat collected from the middle calf area ([ L]sw) of 10 healthy subjects (group 1) and 84 patients suffering from intermittent claudications (group 2, n = 49), from rest pain (group 3, n = 21), and from severe ischemic skin changes (group 4, n = 14). In addition, the effect of a vasoactive drug (naftidrofuryl, 600 mg) or placebo infusion on [L]sw was investigated (n = 30). Results (means +/- SE) showed that 1) [L]sw (mmol/l) increased significantly with the severity of the symptoms: group 1 = 16.5 +/- 0.4, group 2 = 18.7 +/- 0.4, group 3 = 22.8 +/- 0.9, and group 4 = 27.5 +/- 2.0; and 2) [L]sw was reduced by 10% (P less than 0.01) after naftidrofuryl infusion, whereas there was no change after placebo infusion. We suggest that lactate in calf sweat is a good indicator in the evaluation of the severity of peripheral occlusive arterial disease and in assessing the efficiency of vasoactive drug treatment.

[Possible role of a cardiac factor in limiting the walking perimeter in the treadmill test in the arteritis patient]. / Part possible d'un facteur cardiaque dans la limitation du périmètre de marche lors de l'épreuve sur tapis roulant chez l'artéritique.

Electrocardiographic modifications appearing during a treadmill test undergone by 145 patients with arterio-sclerosis obliterans at stage II without coronary antecedents and with normal resting electrocardiograms were studied. Twenty per cent of the patients had to discontinue the test (slope 12%, 3,8 km/h). A repolarization anomaly of ischemia type appeared in 13% of the cases (19 patients) and a rhythm disorder in 1%. Hence systematic monitoring of the electrocardiogram during walking test can enable subjects with high coronary risk to be singled out.

Comparison of the effects of propranolol, pindolol, oxprenolol and acebutolol on atrioventricular conduction in unanaesthetized dogs.

1 Atrio-ventricular conduction (AVC) in the unanaesthetized dog (17 animals) was studied using atrial pacing at progressively increasing frequencies applied via electrodes implanted in the right atrium. In animals habituated to the experimental conditions, beta-adrenoceptor blocking drugs devoid of intrinsic sympathomimetic activity (ISA) modified neither heart-rate (HR) nor AVC, though 4 mg/kg i.v. propranolol transiently raised HR and facilitated AVC. Due to their ISA, pindolol and oxprenolol raised HR and facilitated AVC at high doses. 2 Thus, when not under anaesthesia, the resting dog, in contrast to man, possesses no tonic adrenergic influence which might be suppressed by beta-adrenoceptor blockings drugs. 3 After atropine or pentobarbitone, which considerably increased HR, beta-adrenoceptor blocking effects became clearly visible, and the hitherto reported depressant effects on HR and AVC were observed. However, the ISA of oxprenolol, and especially of pindolol, can partly or completely mask their beta-adrenoceptor blocking action at high doses under these experimental conditions.