Are hemophiliacs naturally anti-coagulated
CVL’s have been used in both children and adults to facilitate the administration of antineoplastic drugs, parenteral nutrition and blood products. In recent years CVL’s have been increasingly used to secure venous access in boys with hemophilia. Current management of very young boys with severe hemophilia has as a primary goal, the prevention of disabling arthropathy which is an inevitable consequence of repeated spontaneous or trauma related bleeding into joints, especially the ankles, knees and elbows. In an effort to prevent chronic joint damage in boys with severe hemophilia many hemophilia centers now begin a program of primary prophylaxis in such patients starting at the age of 1-2 years. The aim of the prophylactic program is to maintain a minimum circulating factor level of 1%; this goal can be achieved by the intravenous administration of 25-40 U/Kg of factor/III on alternate days (minimum x 3/week) or factor IX twice per week for boys with hemophilia A or B, respectively. Successful maintenance of a prophylaxis program in very young boys is a real challenge because of the need for repeated peripheral venous access and as a result placement of a central venous catheter is often recommended.
We report three cases of boys with severe hemophilia A (11 years, 5 years and 1-yearold). They all underwent central venous line (CVL) insertion for primary prophylaxis in the first and the third cases and for the induction of immune tolerance in the second case. In all cases, the CVL was a subcutaneous port-a-catheter and the CVL associated thrombosis was suspected because of malfunction of the port-a-catheter. In one of the boys, the port-acatheter had been in place for 6 months and in the other 2 for over 3 years. In all three boys there was no evidence of an underlying genetic predisposition to thrombosis e.g. activated protein C (APC) resistance. All of them underwent bilateral arm venogram which confirmed the presence of CVL-related thrombosis. Thrombi were located in the left subclavian and brachiocephalic veins in the first and second cases, and in the left brachiocephalic vein in the third case. These findings were unexpected as historically hemophiliacs are thought to be protected from thrombosis by virtue of anticoagulation nature of their disease. Based on this observation, we strongly recommend physicians caring for hemophiliacs to critically evaluate the risks and benefits related to CVL insertion
Although venous access for primary prophylaxis is the most common indication for placement of a central venous line in boys with hemophilia, these devices are also placed in selected patients to facilitate an immune tolerance program in boys with high titer inhibitors. Central venous lines, however, are associated in some patients with significant clinical problems; infection, hemorrhage, thrombosis, thrombophlebitis, dislodgment and rarely subacute bacterial endocarditis. Their use has significant consequences and is the leading cause of deep vein thrombosis (DVT) and pulmonary embolism (PE).
It seems that the frequency of CVL-related DVT in hemophiliacs is high; therefore further studies in larger cohorts of boys with hemophilia and indwelling catheters are warranted to define the true risk of CVL-related thrombosis. It will be important to educate physicians about this complication since the traditional assumption has been that severe hemophilia may “protect” against CVL associated deep venous thrombosis. This information is essential for families and physicians who must weigh risk vs. benefits of these foreign devices in this patient population.
In conclusion, based on our observation we now counsel parents that the risk of catheter related complications is significant. This information should be taken into consideration before a recommendation is made to place a CVL in a very young boy with hemophilia. Physicians who care for these patients should be vigilant about this important complication and a bilateral upper arm venogram should be ordered if there are signs (e.g. dilated veins on the upper chest wall, swelling of the arm, port malfunction that does not resolve with local instillation of fibrinolytic therapy) that may point to an underlying DVT.
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