Low-molecular-weight heparin and calcium heparin in thrombosis prophylaxis in patients with percutaneous arterial and venous ports for colorectal liver metastases

Study objective: The evaluation of low-molecular-weight heparin use to prevent arterial and venous thrombosis in patients with Indwelling arterial Port-a-Cath implants. Methods: From 1996 to March 2003 we placed 370 indwelling hepatic arterial catheters with a minimally invasive approach. The left distal subclavian artery was approached from beneath the left clavicle, then an angiographic study of the tumoral vascular district was performed and the gastroduodenal artery was occluded by an embolus. A polyurethane catheter was introduced distally into the hepatic artery and connected to a reservoir through a 3-4 cm long subcutaneous tunnel. In 90 patients a venous Port-a-Cath was placed for concurrent systemic chemotherapy. All 370 patients received regional chemotherapy and were treated with calcium heparin at a dose of 5000 IU twice a day and with low-molecular-weight heparin at prophylactic doses (dalteparin 2500 IU or nadroparin 3000 IU) during catheter permanence to prevent hepatic artery thrombosis. Intra-arterial trans-port radionuclide scans using technetium-99m-labeled micro-aggregated albumin were performed monthly to check the infusion distribution and hepatic artery patency. In the presence of anomalous patterns, thrombosis, pulmonary embolism or other complications, angiography and/or other diagnostic studies were performed to determine the cause of the vascular event and the local or systemic symptoms. The mean arterial and venous Port-a-Cath permanence times were 6 and 8 months, respectively. Results: We observed episodes of hepatic artery thrombosis in 4.3% of patients. Three of these 17 patients were successfully treated by intra-arterial thrombolysis using urokinase. No venous thrombosis occurred as a consequence of regional and/or systemic chemotherapy, no episodes of arterial thrombosis were registered during arterial catheter permanence, nor did any hemorrhagic complications related to anti-coagulant therapy occur. Five patients treated with low-molecular-weight heparin required treatment suspension due to a platelet count of <40,000/dL. Conclusion: Our experience suggests that low-molecular-weight heparin and/or calcium heparin at prophylactic doses could be useful in the prevention of arterial and venous thrombosis in patients with indwelling arterial catheters or venous Port-a-Cath treated with regional or systemic chemotherapy for hepatic metastases from colorectal cancer. The homogeneity of the patient group and the use of analogous chemotherapeutic drugs (fluoropyrimidines) avoided statistical contamination related to differences between kinds of cancer and between the chemotherapeutic agents used.