The treatment and outcome of cancer patients with thromboses on central venous catheters.

Thromboses are a common complication of central venous catheters in cancer patients. This study was performed to analyze retrospectively the treatment and outcome of all patients with venous thromboses related to central venous catheters at a major cancer center. From 1992 through 1995, 319 oncology patients with central venous catheters underwent radionuclide venography (RNV) at the Dana-Farber Cancer Institute for suspected catheter or venous thrombosis. The treatment and outcome of patients found to have venous thromboses were evaluated. Of the 319 patients, 112 were found to have evidence of venous thrombosis. The median age and platelet counts were not significantly different between the patients with and without thromboses. The most common indication for obtaining RNV was difficulty in aspirating or infusing material through the catheter. Patients who had pain or edema, or both, of the neck or upper extremity were more likely to have a venous thrombosis. Regardless of therapeutic intervention, including anticoagulation with heparin or coumadin, or both; line removal or replacement; or a combination thereof, no patients had a major adverse outcome such as pulmonary embolism, compromise of limb, or death. Only 4 patients did not have resolution of their presenting symptoms, all of whom were treated with line replacement. The overall survival of patients with and without thromboses was not significantly different. Either anticoagulation or removal of the central venous catheter (or both) appears to be adequate treatment for catheter-related thrombosis. A prospective trial to evaluate these approaches may be worthwhile so that the use of unnecessary procedures may be avoided in this patient population.

Normalization of mineral ion homeostasis by dietary means prevents hyperparathyroidism, rickets, and osteomalacia, but not alopecia in vitamin D receptor-ablated mice.

1,25-Dihydroxyvitamin D3 plays a major role in intestinal calcium transport. To determine what phenotypic abnormalities observed in vitamin D receptor (VDR)-ablated mice are secondary to impaired intestinal calcium absorption rather than receptor deficiency, mineral ion levels were normalized by dietary means. VDR-ablated mice and control littermates were fed a diet that has been shown to prevent secondary hyperparathyroidism in vitamin D-deficient rats. This diet normalized growth and random serum ionized calcium levels in the VDR-ablated mice. The correction of ionized calcium levels prevented the development of parathyroid hyperplasia and the increases in PTH messenger RNA synthesis and in serum PTH levels. VDR-ablated animals fed this diet did not develop rickets or osteomalacia. However, alopecia was still observed in the VDR-ablated mice with normal mineral ions, suggesting that the VDR is required for normal hair growth. This study demonstrates that normalization of mineral ion homeostasis can prevent the development of hyperparathyroidism, osteomalacia, and rickets in the absence of the genomic actions of 1,25-dihydroxyvitamin D3.