Red blood cell transfusions should be used judiciously in patients with CKD, especially because of the potential development of sensitivity affecting future kidney transplantation. However, despite the use of ESA and iron therapy, transfusion with red blood cells occasionally is required, in particular in the setting of acute bleeding.
3.4.1 In the opinion of the Work Group, no single Hb concentration justifies or requires transfusion. In particular, the target Hb recommended for chronic anemia management (see Guideline 2.1) should not serve as a transfusion trigger.
Anemia commonly is observed in patients with CKD. The degree of anemia is a reflection of the severity of CKD. Anemia impacts on cardiac function and is associated with increased cardiovascular morbidity and mortality and decreased QOL.262
Typically, the anemia of CKD is chronic, and patients compensate for the anemia through a number of mechanisms. Thus, in determining the need for red blood cell transfusions, it is important to evaluate the state of compensation of the patient. In general, otherwise healthy individuals display few symptoms or signs of anemia at rest when Hb level is greater than 7 to 8 g/dL, although they may show dyspnea with exertion. At 6 g/dL, most patients will report some weakness and, with progressive decreases in Hb values, dyspnea at rest and congestive heart failure (CHF) occur.263 Also, the risk for relevant tissue hypoxia increases, particularly in the presence of vascular disease. Therefore, in general, decisions concerning transfusion are not acute, and there is an opportunity to consider the risks and benefits of transfusion as treatment.
Before considering transfusion of red blood cells for the treatment of chronic anemia, it is essential to assess signs and symptoms and determine the cause of the anemia so that, when appropriate, treatment other than red blood cell transfusions may be used. Classic examples of anemias that may be severe, but correctible by alternative therapies, are iron-deficiency anemia and pernicious anemia in adults.
If red blood cell transfusions are deemed necessary for the immediate treatment of patients with chronic anemia, the goal should be to attain an Hb concentration that will prevent inadequate tissue oxygenation or cardiac failure. When red blood cell transfusions are considered for the long-term treatment of patients with chronic anemia, treatment goals (other than to maintain a certain Hb concentration) should be determined in advance and assessed serially to ascertain whether the goals are being met. In this setting, the physician and patient must consider such questions as: What symptoms and signs are caused or aggravated by the anemia? Can these symptoms and signs be alleviated by red blood cell transfusions? What is the minimum level of Hb at which the patient can function satisfactorily? Do the potential benefits of red blood cell transfusions outweigh the risks (and possibly the inconveniences) for any given patient? In determining the risk-benefit ratio for a given patient, such factors as lifestyle, the presence of other medical conditions, the likely duration of the anemia, and the patient's overall prognosis should be considered. For example, a patient may be willing to tolerate a very limited capacity for exertion if anemia is likely to be temporary, but not if the anemia will be permanent.
In general, risks per unit of red blood cells transfused are the same as in any setting. A number of retrospective studies have identified risks related to aggressive transfusion support. A review of patients with acute coronary artery syndromes revealed a greater mortality rate in transfusion recipients.264 In the presence of severe chronic anemia, transfusion may lead to CHF, particularly in the elderly. In such cases, red blood cell transfusions must be administered very slowly, and, in patients with HD-CKD, transfusion during hemofiltration may be required. The administration of many red blood cell transfusions over a prolonged period can eventually lead to iron overload.
The use of ESAs can greatly reduce the need for red blood cell transfusions in patients with anemia of CKD when target Hb concentrations are reached and maintained.265,266 With the advent of new immunosuppressant regimens after 1995, the benefits of pretransplantation transfusion have been rendered largely obsolete. There is some evidence that donor-specific transfusion with living donor transplantation improves survival, but the decision to perform donor-specific transfusion must still be made on a case-by-case basis. Blood transfusions can induce antibodies to histocompatibility leukocyte antigens that can reduce the success of kidney transplantation; thus, transfusions generally should be avoided in patients awaiting a renal transplant.267 If deemed essential, red blood cell transfusions in this patient group should be conducted in line with published recommendations.268
If therapy with an ESA is started at the Hb concentration recommended in these guidelines and Hb levels are maintained at the recommended target concentrations, blood transfusions should be necessary only for patients with acute bleeding (usually GI), acute hemolysis, or severe inflammation or blood loss through surgery, and then only in an emergency or if the patient exhibits a rapid decline in condition. International guidelines provide criteria for deciding when transfusion is necessary.269-271
Patients with CKD on HD therapy are more likely to need blood transfusions than those on PD therapy because of the HD procedure itself. Patients on HD therapy lose blood from frequent blood tests, trapped blood in the dialyzer and tubing,272 and increased risk for GI bleeding from anticoagulants. However, aggressive iron replacement has largely eliminated the need for red blood cell transfusions, even for patients on HD therapy.