The other 40 percent are due to mechanical problems such as kinks in the catheter. Clots typically develop over time when fibrin, a naturally-occurring substance that promotes blood coagulation, builds up within the body, near the tip or along the catheter. Blockages prevent aggressive, livesaving treatment from being given. Without, in essence a spigot or faucet, aggressive life-saving treatments simply couldn t be given, said Dr. Haire, UNMC professor of internal medicine who specializes in hematology. Furthermore, surgery to remove a catheter and install a new one is not a favorable option, especially for very sick patients undergoing bone marrow transplants.
Any surgical procedure poses a significant health risk.
It isn t practical to use the patient s own veins and puncture a vein every time you need to give medication or withdraw blood for diagnostic purposes. This damages the veins to the point where there may be no usable veins in most people after a few weeks of therapy, he said. Dr. Haire, who specializes in blot clots as well as catheter complications, has published 30 articles on the subjects over the last 15 years, including two in the New England Journal of Medicine and the Journal of the American Medical Association. The six-month COOL study was completed in May 2000. A total of 150 patients with blocked catheters were enrolled in the randomized, double-blind study to find out if Alteplase was effective in restoring function to catheters blocked by clots.