To the Editor.—Freund reported five cases of phlebothrombosis of large veins among 200 patients who received hyperalimentation via polyvinyl catheters (Archives 1981; 116:1220-1221). He reported that phlebography was performed in only two of these patients, and thrombosis of the subclavian vein was demonstrated. It has been suggested that even in patients without clinical evidence of large-vein thrombosis, evidence of clot formation can be detected in about 60% of the cases if phlebography is routinely performed at the time of removal of the catheter.1 I suggest addition of 1,000 to 2,000 units of heparin sodium to each liter of hyperalimentation solution. This has been shown to diminish thrombus formation on central catheter tips.2 Also, addition of heparin decreases the incidence of catheter sepsis.3 Catheter sepsis usually implies either infection of the fibrin sleeve or thrombus within or around the catheter; therefore, addition of heparin to total parenteral