[Effect of X-ray contrast medium on peripheral circulation, arterial blood flow and venous capacity in the lower extremities during phlebography (author's transl)].

The influence of contrast medium (20 ml Meglumine Diatrizoate 65%; Angiografin) on peripheral circulation was studied after injection into the vena saphena magna in 12 patients (mean age 40.5 years) with markedly varicose veins. Pneumatic segment-plethysmography and "mercury-in-rubber" strain-gauge-plethysmography were used to investigate local and systemic effects of contrast medium on intravascular basic volume and pressure-dependent venous capacity. Heart rate was controlled by Ecg-monitoring, venous blood pressure by means of a Schwarzer pressure transducer, and peripheral blood flow by means of pneumatic segment-plethysmography. In addition peripheral vascular resistance was calculated. Local effect of contrast medium on large veins was a small insignificant increase (2.2%) of venous capacity. However, there was a significant increase of additional 10% after recirculation (2 P less than 0.01). Intravascular basic volume showed a significant increase as well (2 P less than 0.01). In addition the calculated increase of total intravascular volume--represented by intravascular basic volume plus venous capacity--was 16.3% related to an intravenous pressure of 70 mm Hg. According to these findings, 20 ml contrast medium enlarges the blood volume dumping into the legs with postural changes by approximately 270 ml. Arterial inflow increased significantly (2P less than 0.01) by 40% after contrast injection, whereas mean arterial blood pressure decreased simultaneously. Consequently a reduction of peripheral vascular resistance of 32% was calculated. The neglectable local effect of contrast medium on pressure-dependent venous capacity is probably due to the markedly reduced distensibility of varicose veins. In contrast a striking effect of contrast medium is observed after recirculation, which is felt to be due to a general vasodilatation of capillary vessels and pre- and postcapillary resistance vessels.