[Measurement of oxygen tension in normal and varicose vein walls]. / Mesure de la pression en oxygène dans la paroides veines normales et variqueuses.

Oxygen tension (PO2) was investigated in vivo in the long saphenous vein from 21 varicose patients (31 veins) during venous surgery and 7 patients with normal venous network undergoing popliteo-femoral by-pass. Measurement was achieved using computerized polarographic system Kimoc 6650 (Eppendorf, Hamburg) providing a microdriven stepwise progression of a needle probe. Oxygen tension profile was similar in both groups of patients. A slow PO2 decrease was observed from adventitia up to the union of the middle and inner thirds of the media where values were at the lowest then followed by a marked increased in the intima and the saphenous lumen. Oxygenation of the two external thirds of the venous wall was provided by vasa vasorum. The average minimum values in the media was significantly reduced in varicose veins compared to no-varicose veins (7,9 mmHg versus 13,4 mmHg; p < 0,05). These results indicated the key role of vasa vasorum flux in the long saphenous vein nutrition and suggest a primary or secondary deficiency in oxygen supply in varicose veins.

[Transport and localization of troxerutin in the venous wall]. / Transport et fixation de la troxerutine dans la paroi veineuse.

The vein wall is nourished by diffusion of blood nutrients from the lumen and from the vasa vasorum. It is likely that drugs take the same ways to reach and diffuse through the vessel wall. Thus the uptake of a drug with affinity for the vein wall should give information on its transport to the tissue. This study aimed to explore troxerutin uptake by the long saphenous vein. Troxerutin is a naturally fluorescent flavonoid which has been known to improve subjective signs of patients with chronic venous insufficiency. Nine patients undergoing surgical treatment of varicosis were enrolled in the study. They received for the last 4 days before surgery either 3,500 mg of troxerutin (n = 4) or 1,000 mg twice daily (n = 2). Three patients as controls did not receive any drug. Two samples from thigh and calf long saphenous vein were harvested in each patients and investigated with a confocal laser scanning microscope developed by our institute measuring the fluorescence emitted by troxerutin after excitation by a 458 nm wavelength laser-beam. The intensity of the overall fluorescence was significantly higher in the treated groups (p < 0,001) and slightly higher in the patient who received 3,500 mg of troxerutin than with the lower dosage. The outer wall region provided the highest fluorescence in the treated group while a significant difference was observed in the fluorescence of the medial region between treated and control group. These results showed a marked affinity of troxerutin for the venous wall. The highest uptake in the outer wall region is likely to result from transport through vasa vasorum, owing to the rheologic properties of the drug. The significant medial fluorescence may account for the venous tone improvement with the drug.

The affinity of troxerutin for the venous wall measured by laser scanning microscopy.

The uptake and localization of troxerutin, a trihydroxy-ethyl-rutoside, in the venous wall have been studied in patients undergoing long saphenous vein surgery. Troxerutin, an autofluorescent drug, is currently used to relieve oedema and subjective symptoms in patients with chronic venous insufficiency. In order to determine the localization of the troxerutin, a confocal scanning laser microscope has been used to record the fluorescence from vein cross sections. The quantified fluorescence was used as a measure of the local concentration of troxerutin. In order to reduce the effects of local variation, several images have been scanned from each specimen. Then the recorded data have been analysed to see how the fluorescence varies in the radial direction within the venous wall. Results showed that troxerutin was significantly accumulated in both inner and outer parts of the venous wall. Whereas inner wall troxerutin uptake resulted from direct diffusion through the lumen, the outer wall uptake proceeded likely from the vasa vasorum circulation.

[Rheological parameters in hemorrhoid pathology]. / Etude des paramètres rhéologiques dans la pathologie hémorroïdaire.

The authors studied erythrocyte aggregation in 62 patients suffering from hemorrhoidal disease, distributed on the basis of proctoscopy findings between three groups (recent uncomplicated congestive attack, recent thrombosed hemorrhoid, stage IIb or III chronic prolapse). This hemorheological parameter is a sensitive marker of circulatory stasis. Values measured were compared with those obtained in 21 healthy subjects. Erythrocyte aggregation index was significantly higher in patients than in controls (31.6 +/- 6.8 versus 27.7 +/- 4.4) (p < 0.05). This difference was due essentially to increased values in patients with acute hemorrhoid problems. A parallel increase in blood fibrinogen was found in these same patients. Hemorheological changes could predispose to worsening of venous stasis in the hemorrhoidal circulation and participate in the onset or spread of thrombotic processes.

Possible role of drug interactions in bupivacaine-induced problems related to intraventricular conduction disorders.

Clinically, bupivacaine has depressant effects on intraventricular conduction that may lead to serious atrioventricular blocks or reentrant arrhythmias at plasma levels below those required to produce these effects experimentally (2-3 micrograms/ml instead of 8-10 micrograms/ml). The difference could be due to drugs present in the blood at the time of regional anesthesia that similarly inhibit conduction. This hypothesis was examined in 30 anesthesized, closed-chest dogs by measuring conduction time in the ventricular contractile fibers as well as effective refractory period under pacing at a constant, relatively high (180 beats/minute) rate. Changes in sinus rate were limited, as well as changes in ventricular effective refractory period and blood pressure regardless of the drug tested. In contrast, cibenzoline, disopyramide, and propranolol increased conduction time and lengthened QRS duration. Clomipramine appeared to prolong conduction time and widen QRS only moderately in therapeutic doses, whereas verapamil did not manifest noticeable effects on conduction. Caution is therefore recommended in regional anesthesia with bupivacaine in subjects being treated with cardiovascular drugs, such as cibenzoline, disopyramide, and propranolol and their congeners, or even by tricyclic antidepressants.