[Local thrombolytic treatment of peripheral arterial thrombosis and embolism]. / Lokal trombolytisk behandling av perifer arteriell trombose og emboli.

Local intra-arterial low-dose thrombolysis has become a therapeutic alternative for acute and subacute occlusion of vascular grafts and native vessels in the lower limbs. The series comprises 31 patients treated with Streptokinase as thrombolytic agent. Complete primary thrombolysis was achieved in 20 patients, whereas in 11 patients the outcome was only partially successful or a failure. Vascular stenoses were considered to precipitate thrombosis in 18 cases, and prompted percutaneous transluminal angioplasty after thrombolysis. Two-year patency was 48% (30-66%) in the total series and 74% (56-92%) among the patients with successful primary thrombolysis. There were no major complications. Five patients sustained local inguinal haemorrhage, of whom three required surgical revision. Local intra-arterial thrombolysis is an elaborate procedure associated with potential hazardous complications. It should be carried out in institutions with radiological and vascular surgical expertise.

Roentgen contrast media and fibrinolysis.

A review of the literature on the influence of contrast media (CM) on fibrinolysis showed that information currently available is contradictory, inconclusive and fragmentary. Results of some in vivo studies suggest that both ionic and nonionic CM increase fibrinolytic activity, either by lowering plasma plasminogen activator inhibitor 1 levels, by releasing endogenous tissue plasminogen activator and¿or by altering the fibrin meshwork of thrombi. Most in vitro studies on the subject contain results that are contradictory to those from in vivo studies. The discrepancies are due to obvious differences between systems which are, at best, only comparable under conditions of stagnant flow. Thus, great care should be exercised when extrapolating or interchanging data obtained in vivo and in vitro.

The effect of various contrast media on the activation of plasminogen by streptokinase or recombinant tissue plasminogen activator in vitro.

RATIONALE AND OBJECTIVES: Radiologic contrast media (CM) may influence processes of coagulation and fibrinolysis. In the current study, the effects of various CM on the formation of plasmin were examined in an in vitro buffer system. METHODS: The effects of three clinically relevant concentrations of seven different iodine-containing CM and gadolinium-DTPA on streptokinase (SK) or recombinant tissue plasminogen activator (rt-PA)-induced plasmin formation was monitored using a plasmin-sensitive chromogenic substrate. RESULTS: Contrast media generally had an inhibitory effect at the plasminogen activation step; this effect was particularly noticeable with the ionic CM. CONCLUSIONS: Contrast media influence plasminogen activation by SK and rt-PA in vitro. Ionic CM have a more pronounced inhibitory effect than the nonionic media. The ionic Gd-DTPA shows a less inhibitory effect than the ionic iodine-containing CM. However, they must be regarded separately because of the different chemical composition of the magnetic resonance imaging and x-ray CM.

[Recanalization of arterial occlusions by laser]. / Rekanalisering av arterielle okklusjoner ved hjelp av laser.

Recanalization of arterial occlusions by laser light application has attracted much interest in recent years. Extensive investigations have been carried out to evaluate the optimal delivery system, in order to minimalize the rate of perforation. Systems based upon conversion of laser energy to thermal energy has been tried out. The laser probe as well as the sapphire tip create a channel through the occlusion by thermal ablation. A guide wire is thereafter passed through the narrow channel in order to perform an ordinary balloon dilatation. Other lasers are currently being investigated. Both the lasers themselves and the required disposable equipment, are relatively expensive. Laser recanalization of arterial occlusions is still being investigated. The clinical benefit in the therapy of arterial disease remains to be seen.