SUPPRESSION OF HEPARINIZATION OF CENTRAL VENOUS CATHETERS BETWEEN CYCLES OF CHEMOTHERAPY - RESULTS OF A PHASE-I STUDY

A phase I study to evaluate heparinization of tunnelled subclavian cat heters (TSC) was conducted in 42 patients who each had a TSC for chemo therapy. They were enrolled in the study from August 1994 to December 1995. The inclusion criteria were: age 18-70, no general anticoagulant treatment, TSC used only for chemotherapy, informed consent. Heparini zation was performed at the end of each cycle and then at increasing i ntervals: 11, 13, 15, 17, 19, and 21 days. A 21-day interval was inten ded to mimic the suppression of heparinization between cycles. Heparin ization was performed with a 250 IU/ml heparin solution. Anti-Xa activ ity was studied before each heparinization. For each interval, at feas t 5 patients were followed up for two cycles. If no blockages were pre sent progression to the next step was authorized. If one blockage was observed 5 additional patients were required to have their TSCs hepari nized after the same interval. Two blockages (block) after the same in terval meant that the previous interval was recorded as the longest to lerable. There were no blocks with the 11-day interval (6 patients), 1 block after 13 days (10 patients), 1 block after 15 days (10 patients ), and no blocks after 17 days (5 patients), 19 days (6 patients), or 21 days (5 patients). The median anti-Xa activity (curative rate 0.2-0 .6) was, respectively 11 days 6.74; 13 days 5.47; 15 days 4.71; 17 day s 3.61; 19 days 3.67; 21 days 5.10 (NS). Heparinization between two cy cles of chemotherapy is unnecessary. A high level of heparin activity persisted constantly inside the catheter lumen through the 3-week obse rvation period.