[Evaluation of the obstructive factor and its importance in the caval and ilio-caval postphlebitic syndrome].

As regards venous haemodynamic disorders, former caval and ilio-caval phlebites constitute a separate group in the vast structure of phlebitic after-effects. The wealth of collaterals (reminder of the physio-pathology) and the slightest affection of the upper venous system in the case of high isolated thrombosis show that they may be effectively compensated. This idea, already apparent in certain clinical and phlebographical findings, is confirmed by functional investigations, and especially by plethysmography under venous occlusion. It is this method that we have used in this study. We have retained only the lesions of the ilio-caval system considered some way away from the acute stage of the thrombosis (gap of more than 6 months). A first approach, using rheoplethysmography, confirms that the obstructive syndrome associated with caval obstruction alone is generally well compensated by the development of an efficient collateral circulation, and that disorders of venous return, evaluated by the outflow index, are mainly to be seen when the caval obstruction is associated with deterioration of the subinguinal venous system. A second approach showed, by means of a more far-reaching analysis of the parameters using a constrictive mercury gauge that besides venous repermeation and supply through the collateral network a role was played by venous distensibility disorders induced by phlebitis... The maintenance of satisfactory distensibility could therefore come into play as a contributory factor in compensation phenomena. These facts confirm the complexity of post-phlebitic illness; phlebography gives only an incomplete insight into the functional repercussions of the obstructive syndrome; the exection of functional experiments demonstrate that often apparently significant venous obstructions are in fact quite well compensated.