[Fibrinolysis of deep venous thrombosis on implantable perfusion devices. Apropos of a consecutive series of 57 cases of thrombosis and 32 cases of fibrinolysis]. / Fibrinolyse des thromboses veineuses profondes sur dispositifs de perfusion implantables. A propos d'une série consécutive de 57 thromboses et de 32 fibrinolyses.

The main complication of totally implantable venous access devices is deep venous thrombosis on catheter. It may dramatically reduce the already limited venous capacity of patients undergoing chemotherapy and obturate catheters, causing pulmonary embolism or functional disorders. These thromboses usually involve veins of the superior vena cava system where the catheters are implanted. Generally, they occur early, are extensive and often asymptomatic. Doppler ultrasonography is the diagnostic investigation of choice, phlebography being reserved for particular cases or to specify the limits of the thrombus. In a series of 412 vein access devices implanted and systematically monitored by Doppler ultrasonography, we found 57 thromboses (13.8%), 15 partial and 42 complete. The lowest thrombosis rate was observed in the right internal jugular vein (10% vs 20 to 23%, p = 0.006). Thirty-two patients received a systemic fibrinolytic treatment, 16 with streptokinase (SK), five with urokinase (UK), four with tissue plasminogen activator (rt-PA) and seven with SK/UK association. No serious side effects were observed. Sixteen repermeabilizations (50% of fibrinolysis) were obtained. There were no significant differences with respect to the fibrinolytic, the initial characteristics of thrombosis or the patients. Patients without fibrinolysis received 3 weeks of low molecular weight heparin (curative doses) then warfarin. Only one patient was repermeabilized with this treatment (significative difference with fibrinolysis: p = 0.009). Fibrinolysis is indicated in symptomatic thrombosis and/or in cases of extension to the innominate vein or the superior vena cava. Systematic monitoring by Doppler ultrasonography and prophylactic anti-thrombotic treatment are recommended in patients with implantable venous access devices in order to decrease the occurrence of thromboses, to detect asymptomatic patients at an early stage and to increase the effectiveness of fibrinolysis.

[Deep venous thrombosis on implantable infusion devices. A prospective study of 72 patients with Doppler ultrasonography of veins of the neck (jugular, subclavian and brachiocephalic trunk)]. / Thromboses veineuses profondes sur dispositifs de perfusion implantables. Etude prospective de 72 patients par échotomographie-Doppler des veines du cou (jugulaire, sous-clavière et tronc brachio-céphalique veineux).

Seventy-two consecutive patients with totally implanted catheters for administration of chemotherapy for solid tumours or lymphomas were studied prospectively to assess the prevalence of venous thrombosis. During the follow-up period of 343 (6-1,177) days, 11 cases of venous thrombosis (15.2%), of which 45% were partial and only 36% symptomatic were observed. Venous thrombosis was an early complication, 6/11 cases being observed within 1 month of implantation. No clinical or biological predisposing factor, apart from the presence of malignant disease, could be identified. Doppler ultrasonography is a good method of following-up these patients. This method should become an essential diagnostic tool in this field.

[Heart rate and rhythm during flight in civil pilots undergoing aerobatics. A Holter study]. / Fréquence et rythme cardiaques en vol chez les pilotes civils pratiquant la voltige aérienne. Etude par la méthode de Holter.

Variations in heart rate and arrhythmic risk were analysed during aerobatic manoeuvres carried out by 23 amateur pilots, affiliated to an air club or in the French national team, during training or competitive flight, by 43 Holter 2-channel continuous electrocardiographic recordings. The maximum, mean and minimum heart rates were raised before the flight started and were observed to attain or even exceed the age-predicted maximum heart rate during the manoeuvres. These values were independent of age, the pilot's experience, the acceleration forces, the duration of the flight or the aerobatic figures performed. On the other hand, the heart rate was much higher during competition than during training and pilot experience modified its variations, indicating that psychological stress played a major role in inducing the tachycardia. Aerobatic flying was only mildly arrhythmogenic, inducing some isolated extrasystoles and one short run of asymptomatic supraventricular tachycardia. Holter recording is a simple and economic method of monitoring aerobatic pilots and could help to improve training methods and our understanding of the physiological changes observed during flight.

[Experimental prevention of deep venous thrombosis with low-molecular-weight heparin using implantable infusion devices]. / Essai de prévention des thromboses veineuses profondes sur dispositifs de perfusion implantables par une héparine de bas poids moléculaire.

We studied the effect of a fractionated heparin, Dalteparine Sodium, on the prevention of thrombosis of veins of the superior vena cava system catheterized by implantable infusion devices. Forty-six patients with solid or lympho-proliferative tumors, whose clinical condition required installation of a such device, were successively included into the study in 1991. The anticoagulant was administered for one month following implantation at the dosage of 2,500 anti-Xa units per day. The development of deep vein thrombosis was investigated by systematic Doppler ultrasound before the first and third months and at 1 year. Three early (D9, D12 and D16) and asymptomatic thrombosis were diagnosed (6.5%). This rate, although clearly more favourable, was not significantly different (p = 0.254) from the rate of 15.2% previously reported in a group of 72 comparable patients, but who did not receive preventive treatment. These results demonstrate the necessity and feasibility of a randomized study on a larger number of patients testing several protocols, before concluding on the efficacy of this type of preventive treatment.

Doppler ultrasonography of normal neck veins.

Doppler ultrasonography was used to examine 198 neck-vein systems (67 right, 131 left) in 148 patients. The vessel lumen is usually echo-free: the veins are supple, and the internal jugular and sometimes the subclavian veins can be compressed. The venous confluence is Y-shaped. Blood flow was symmetrical and biphasic in 57% of cases, continuous in 29% of cases, and monophasic in 13% of cases. Blood flow velocity was less than 1 m/s in all cases and varied with respiration and heart rate. Color Doppler allows flow imaging and increases the speed and reliability of the procedure. This investigation is useful for following-up patients with indwelling venous catheters and is the investigation of choice whenever pathology of the neck veins is suspected.