Anemia is present in approximately one third of patients with heart failure. There are multiple factors that can contribute to these conditions co-existing. And it is hard to say in general terms if one is causative of the other. They do have several risk factors in common, some of which are chronic kidney disease, diabetes mellitus, inflammation, advanced age and exposure to toxins such as chemotherapy.
It appears that in some cases, heart failure can lead to anemia and in others the opposite is true. There are many complex mechanisms that go into the domino effect of each of these scenarios, but in simplified terms… if a person has heart failure that leads to things like renal dysfunction, inflammation, nutritional deficiencies, or blood loss or is on a medication such as an ACE inhibitor or beta blocker… these things can then lead to anemia.
On the flip side, if a person has anemia (due to any number of reasons) – this would cause the need for an increase in their cardiac output in order to get the needed amount of oxygenated blood to all the tissues and organs that need it. This, in turn, can overwork the heart and lead to heart failure.
The combination of anemia, chronic kidney disease and iron deficiency in patients with heart failure often occurs and is associated with progression of these disease processes and poor prognosis. So, although you could surmise for each specific case you encounter that one diagnosis may have led to the other, it is still unclear whether anemia leads to advanced heart failure and worse outcome or if anemia is merely a sign of more advanced disease.
Treatment Options:
When treating anemia, the logical solution would be to try and increase Hgb levels. Traditionally, this has been successfully accomplished though administration of blood transfusions. In the person with heart failure however, there are added risks of possible volume overload and ischemic events and has not shown significant difference in overall outcome despite a measured increase in Hgb.
Erythropoiesis-stimulating agents (ESA) are medications which stimulate the bone marrow to make red blood cells. They are often used to treat anemia due to end stage kidney disease, chemotherapy, after major surgery, etc. When used in the heart failure population, as with blood transfusions… the Hgb levels did improve, but this type of therapy has been shown to increase the risk of thrombolytic events and ischemic stroke. Because of this risk, this type of therapy is not recommended for people with heart failure.
Iron deficiency is quite prevalent among anemic patients, showing that approximately 70% of anemic patients are also iron deficient and about 50% of people with heart failure are iron deficient. Clinically it is advantageous to screen all heart failure patients for iron deficiency, regardless of what their Hgb levels are. Based on the research, it seems that the most promising treatment for patients with anemia and heart failure is Intravenous Iron Therapy. This type of treatment has been shown to improve the New York Heart Association functional class, exercise capacity and VO2 max, and quality of life and does not have the same risk factors associated with it as the previously discussed treatments do.
Visit the American Heart Association for information and great printer-friendly resources: www.heart.org
Clinical Implications:
Activity Tolerance –
Clinically speaking, one of the main things you will notice in your patients will be a decreased tolerance to activity and exercise. In a person who is otherwise healthy, anemia causes your system to try and compensate for the lack of Hgb by increasing heart rate and stroke volume in order to try to get the lessened amount of oxygen out to the rest of the body. These functions are going to be impaired in the heart failure population. This would then lead to decreased in oxygen delivery and an increase in the symptoms they may already be experiencing – shortness of breath and fatigue. This can make exercise and even basic daily activity more difficult.
And there is no doubt that it is difficult for these patients to be active. But it is also extremely beneficial to keep moving. It’s true – exercise is not always tolerated well by patients with heart failure (even before we start talking about if they may be anemic or not) … and the intolerance of exercise in heart failure with preserved ejection fraction is thought to be due to the way in which our bodies are using oxygen and not necessarily due to the overall reduced cardiac output. This could be either from the decrease in the amount of oxygen delivered to the muscles during exercise (possibly due to anemia) or the inability of the muscles themselves to use the oxygen that is delivered.
But the fact that exercise is not well tolerated is not a reason to avoid it. Some studies suggest, that if we use high-intensity exercise with this population, it will actually improve the ability of our bodies to deliver and use oxygen (which, remember – is the reason the intolerance may be occurring in the first place). The improvement with oxygen consumption can then show decreases in inflammatory processes, improvement with cardiac filling pressures, improvement with exercise capacity, quality of life, and will reduce the morbidity and mortality of this population.
And when we say ‘high-intensity’… what does that mean? High intensity to you will be different than high intensity for your patient and even different still for an elite athlete. It can be very subjective if we allow it. A very easy and practical way to measure and track intensity of exercises is to calculate your patient’s Max Heart Rate (which is 220-age)… then figure out at what percentage of that heart rate you want them to be working. When you are looking to formulate a range for your patients to stay in during exercise – Target heart rate during moderate intensity activities is about 50-70% of maximum heart rate, while during vigorous physical activity it’s about 70-85% of maximum. So, depending on other comorbidities and the fragility of your patient, you may want to stay in the lower range, but if they can handle the higher level, go for it! After you figure out their exact heart rate range that they should stay in, you want to provide the numbers to them and also let them keep a pulse ox on their finger during the activity you are having them do. They can check it periodically and ensure that they are still working at the most effective intensity… then if their heart rate falls below, that will cue them to work harder or go faster.
In addition to making sure that the intensity is high enough, there are other studies to suggest that the mode of exercise matters. Heart rate recovery immediately after exercise reflects parasympathetic activity, which is markedly reduced in heart failure patients. One study demonstrated that both continuous and interval exercise training programs improve exercise capacity. However, continuous training improves earlier heart rate recovery, suggesting more benefit to the autonomic nervous system which has been impaired in those with heart failure.
Exercise has benefits outside of the physiological changes that it brings as well. It has been shown to act as a primary preventative measure, and if implemented will be a means for patients to avoid developing heat failure in the first place. If your patient does have a diagnosis already, exercise can still help with secondary prevention. It will improve symptoms and cardiac functioning in those who already experience heart failure. This is great news for both us therapists and for those at risk! Exercise is what we do – and with a little training and education, we can work to improve the disease process and quality of life. In addition to helping prevent disease or complication of disease, exercise tolerance, compliance, or impairment can also have predictive qualities and is a reliable prognostic indicator of future health.
It is also important for us as clinicians to know, and to impart onto our patients, that completing the rehabilitation program is fantastic, but that it does not mean that the results will be sustained. Studies have shown that of exercised and non-exercised patients, the exercise group initially exceeded but when left without training for 6 months, were performing at the same level as those who had not completed a training program whatsoever. It is essential for our patients to be in an ongoing and sustaining program or to alternatively have a program that they are motivated to complete on their own.
Cognition –
Heart failure has also been associated with cognitive impairment. Patients with heart failure who have anemia have been identified in the literature as having a greater than four times more risk of cognitive impairment compared to the heart failure patients who did not have anemia.
Functionally speaking, we would want to take note of their ability to complete activities of daily living and perform their basic care needs, manage their medications and any other tasks that they would normally complete. These tasks may warrant intervention by the therapy team but may also require support and education to the caregivers as these patients may require more support from a cognitive standpoint than they did previously.
A Speech Language Pathologist referral is not something you would think of first when dealing with people with heart failure but given the correlation between heart failure and cognitive impairment, it would be worth having someone complete a more comprehensive evaluation to provide a more well-rounded plan of care. This could also lead to a discussion about making a standard to at the very least screen cognitive function in these patients to determine the need for further referral and assessment.
As you can see there are many aspects of heart failure that we may not initially think about… or think that we can help with! But as we find out more about this disease process, it’s encouraging to know that we can continue to be creative in our approach and make simple, but meaningful, changes in our patients’ lives!
To learn more about the (not so obvious) aspects of heart failure, check out our short (but information packed!) webinar – Update Your Care Plan: Heart Failure.
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