Forty patients aged > @ years with severe chronic venous insufficiency ( CVI ; C@-C@ ) successively donned compression stockings in a randomized order : one @mmHg ( CS@ ) or two superimposed @mmHg ( CS@ +@ ) , each with open toe ( CS-o-t ) and closed toe ( CS-c-t ) , using donning devices ( three foot slips for CS-o-t ; two foot slips and three frames for CS-c-t ) .