We studied the relationship between activated protein C (APC) resistance and the central venous devices (CVD)-related complications in 61 cancer patients (44 females 'and 17 males, median age 50 years, 71 CVD) from November 1994 to November 1995. Two patients (3.3%) had APC resistance, i.e., APC ratio < 2. Twelve episodes of bactercmia, 8 site infections, 31 cases of CVD dysfunction requiring urokinase (UK), and 3 CVD-retated thromboses were noted. With Cox's proportional hazard models, low APC ratios and high d-dimer levels were significantly associated with CVD-related bacteremia (p = 0.0207 and 0.0210). Such an association was not observed with site infection and CVD dysfunction. The incidence of thrombosis was too low to be analyzed. However, one patient with APC resistance developed subclavian vein thrombosis, leading to eventual removal of the catheter. The prevalence of APC resistance in cancer patients and its association with bacteremia are discussed. Key Words : Activated protein C resistance—Central venous catheters—Bacteremia— Catheter site infection—Thrombosis. Activated protein C (APC) resistance was recently discovered to be the most common inherited cause ' of a hypercoagulable state, accounting for 20-60% patients with deep vein thrombosis (1-6). It has also been associated with arterial thrombosis (7-10), although such an association has been a matter of controversy (11)(12)(13)(14). More than 95% of APC resistance cases are due to a point mutation in clotting factor V with arginine 506 to glutamine, termed factor V L,eiden (4;5;25}: Central venous devices (CVD) are widely used in cancer patients, and CVD-related infections and thromboses are not uncommon. We report a study of the relationship between APC resistance and CVD-related complications in cancer patients.
PATIENTS AND METHODSCancer patients who had CVD in situ and were followed at the Southwest Cancer Center from November 1994 to November 1995 were included in the study. Patients who had CVD placed before November 1994 were studied retrospectively. APC resistance assays were subsequently performed. Patients who had CVD placed during the study period were prospectively monitored. These patients had an APC resistance assay, prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen, fibrin degradation product (FDP), and d-dimer levels performed within 2 weeks of CVD placement. In addition, the following data were obtained from the medical records: age, sex, histological types and stage of the cancer, dates and sites of CVD placement, CVD subtypes, dates of onset of CVD-related complications (definitions provided herein), CVD removal, and the reason for CVD removal. CVD placement and care ~ . All CVD were placed in the operating room under local anesthesia by highly experienced surgeons. All patients were instructed on the care of their CVD by experienced registered nurses. The care of all CVD was standardized by our hospital policy.