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Congestive Heart Failure
Congestive Heart Failure
Marwan Nussairat
HA533
April 27th , 2012
Park University
Dr. Ellen DorshowGordo
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Congestive Heart Failure
Abstract
Epidemiology is used widely to help us better understand diseases, how they work, and
how they are transmitted. This helps us to better treat the disease. The process of epidemiology is
lengthy but must be followed accurately to ensure correct diagnosis and treatment. Epidemiology
is used when a new disease is found and when an old one reappears in high numbers. A common
disease in the elderly is congestive heart failure (CHF). The epidemiology process can be used
to better understand the disease, what causes it, and how to treat it.
Now days, drugs manufactures are competing to develop new drugs to treat this condition
, because many researches and studies shows that there is profound impact that congestive heart
failure has on life expectancy and quality of life. Despite favorable effects on (aspects of) quality
of life in short term studies, several of these new agents have been shown to reduce survival in
mortality trials. However, patients with severe congestive heart failure may experience such
incapacitating symptoms that the question should be raised as to whether an improvement in
quality of life makes the increased risk of mortality associated with these new agents acceptable.
Unfortunately, most clinical trials in which both mortality and quality of life are evaluated fail to
provide information on this composite probability.
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Congestive Heart Failure
Epidemiology
According to the World Health Organization (WHO), “Epidemiology is the study of the
distribution and determinants of health-related states or events (including disease), and the
application of this study to the control of diseases and other health problems. Various methods
can be used to carry out epidemiological investigations: surveillance and descriptive studies can
be used to study distribution; analytical studies are used to study determinants” (WHO, 2011).
To put this definition into simpler terms epidemiology is the study of disease in humans
or animals and focuses on when and where they happen. Epidemiology tries to determine what
causes disease and what people can do to prevent disease. Epidemiology was first used when
scientists tried to discover causes of diseases such as smallpox and polio (Cornell University,
1993). Epidemiology is no longer limited to transmissible diseases. Interestingly, epidemiology
can never prove a cause of a specific disease. It can only show that a certain risk factor correlates
with a higher rate of a specific disease. For example, epidemiology could not prove that smoking
causes lung cancer; only that people who smoke cigarettes have a higher rate of lung cancer.
Epidemiology shows correlation (Cornell University, 1993).
Epidemiology involves specific steps in order to determine the cause of a specific
disease. Using the correct system is imperative to finding the correct answer, quickly. Step one
is preparing for the fieldwork which involves researching the disease, gathering necessary
equipment, and consult with all individuals involved in the investigation. Step two is to
determine if an outbreak has occurred. Just because there is an increase of a specific disease does
not mean an outbreak has occurred. Researching census records is part of step two. After an
outbreak has been verified step three is to verify what the disease is. A specific name may not be
Congestive Heart Failure
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available however the nature of the disease should be determined. Step three involves reviewing
all clinical findings including laboratory tests. Step four is defining and identifying cases.
Criteria should be set that can be used to determine whether or not a person has the disease. Also,
counting how many people are confirmed to have the disease.
Step five is using person, place, and time to help characterize the disease. This step is
vitally important in the accuracy of the investigation and the data will be collected several times
throughout the investigation. This would be who has CHF, how long they have had it, and where
they live. Step six is developing a hypothesis, which will help us to determine why and how the
outbreak occurred. Step seven is evaluating the hypothesis to see if it accurate. There are two
ways of establishing credibility: comparing the hypothesis to facts and using analytic
epidemiology. An example hypothesis would be that individuals who experience high blood
pressure earlier than age 35 have a high incidence of CHF. Step eight is refining the hypothesis
and doing extra investigations if needed. If analytical epidemiology does not prove the
hypothesis right then looking for a different way of transmission should be done.
Step nine is executing prevention of the spread of the disease. Although this is listed as
step nine, prevention measures should be started as soon as the disease and mode of transmission
are identified. Congestive heart failure may not be 100% preventable but patients can take steps
such as consuming a low-sodium diet and limiting fluid intake. Step ten is spreading the word.
The official way of doing this is a conference with local health authorities along with a written
report. This briefing will explain the disease, how it is transmitted, and most importantly, what
can be done to prevent further spread. This educational briefing is imperative to be accurate
because these health officials use this information to educate the general public.
Congestive Heart Failure
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“The transmission of communicable disease depends on the successful interaction of the
infectious agent, the host, and the environment” (Stanhope & Lancaster, 2008). Infectious
agents include bacteria, viruses, funguses, and parasites. The host would whatever is hosting the
infectious agent such as human or animal. The environment is everything that is on the outside of
the host. This includes passing the infectious host to others.
There are two ways an infectious agent can be spread. The first is vertical transmission,
which is the transmission from parent to child. The second is horizontal transmission, which is
the transmission from one person to another. Horizontal transmission can be through sexual
contact or even airborne. Infection is the entry and development of an infectious agent in the
host. Disease is the outcome of an infection. Disease is when the host shows clinical signs of the
infection.
Communicable diseases can be spread many ways. Airborne, by bodily fluids, by touch,
by sexual contact, even through animals or insects. The epidemiology triangle is comprised of
the host, agent, and environment. The center of the triangle is time, which is the amount of time
the agent takes to spread (Stanhope & Lancaster, 2008).
Heart failure (CHF) is a cardiac disease that is caused by some kind of abnormal heart
function. The result is the heart not being able to pump enough oxygenated blood to the body, or
decreased cardiac output. When the ventricles fail at pumping, congestive heart failure results.
Hypertension, coronary artery disease, and mitral or aortic valvular dysfunction are the most
common causes of CHF (American Heart Association, 2010).
Once a patient is diagnosed with CHF the next step is differentiating between which is
weakened: systolic or diastolic. The long-term treatment is different between the two. Evaluating
the ejection fraction will tell the patient this answer. Systolic dysfunction is defined as an
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ejection fraction less than 40%. Diastolic dysfunction is the left ventricle not being able to fill
properly and occurs secondarily due to loss of elasticity (Rasmussen & Renlund, 2006). Diastolic
dysfunction.
Treatment of CHF should be pharmacological and non-pharmacological. Patients should
know the presenting signs of CHF worsening such as shortness of breath, weight gain, and
inability to perform normal daily activities. Up to 65% of hospital admissions are due to the
patient’s noncompliance with treatments (American Heart Association, 2010). Part of a treatment
plan should be a no added salt diet, which is 2-3 grams of salt per day. Some may need daily
fluid intake restricted as well. Pharmacological treatment may include diuretics, ACE inhibitors,
beta-blockers, digoxin, and aspirin.
Class IV is patients with symptoms (dyspnea and fatigue) while at rest. Class III is
patients who are comfortable at rest but have symptoms with the littlest exertion. Class II is
patients that present symptoms with normal amount of exertion and Class I are patients whose
symptoms occur only as often as an individual without CHF. CHF cannot always be prevented
so when patients are classified under Class I the secondary prevention measures are used.
There are two types of epidemiological studies: descriptive and analytical. Collecting
information that is used to encapsulate the problem does a descriptive study. Comparing groups
to find the similarities that may have caused the disease does an analytical study. Studying CHF
is best done using the descriptive study. Finding a common cause that contributes to the disease
is most helpful in treating it. If sodium is found to aggravate CHF then it can be concluded that a
low-sodium diet is useful in treating the disease.
There are three levels of prevention: primary, secondary, and tertiary. All are used when
it comes to treating CHF. Primary prevention is what everyone strives for. This means
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preventing the disease before it happens (Center for Disease Control, 2011). Getting regular
physicals and eating a heart healthy diet are primary prevention in CHF.
Secondary prevention is find and treat the disease early. An example would be checking
blood pressure and weight frequently. If the weight increase has already happened we have not
prevented it, but found it early so that it is easily treated. Tertiary prevention is preventing further
damage from a disease someone already has (Center for Disease Control, 2011). The goal is to
lessen pain and complications from the disease as well as slow the disease. Taking lasix to treat
CHF falls under this category.
CHF Treatments (Clinical Trials)
Congestive heart failure has a profound impact on quality of life and life expectancy.
Dyspnoea and exercise intolerance pose major limitations to the daily activities of patients with
congestive heart failure. In the management of congestive heart failure, loop diuretics and ACE
inhibitors are the mainstays of therapy. Depending on the characteristics of the disease for the
individual patient, a beneficial effect may also be obtained by adding digoxin and vasodilators to
the treatment regimen. However, even with the most optimal treatment currently available, many
patients experience incapacitating symptoms and their life expectancy is reduced significantly.
Furthermore, epidemiological studies indicate a marked increase with age in both the incidence
and the prevalence of congestive heart failure.
The expanding knowledge of the pathophysiology of congestive heart failure has failed to
provide substantial progress to the usual pharmacotherapeutic treatment of this condition, and
prognosis of patients with congestive heart failure has remained poor, both in terms of life
expectancy and quality of life. Over the years, several promising new drugs developed for the
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Congestive Heart Failure
treatment of congestive heart failure have been shown to decrease survival in double blinded
randomized clinical trials (table I).
Trial
Total
number
patients
the trial
Drug (dosage)
of
in
Xamoterol
516 Xamoterol (200mg twice daily)
Enoximone
151 Enoximone (50-100mg 3 times daily
PRIME-II
1906 Ibopamine (100mg 3 times daily
PROMISE
1088 Milrinone (40 mg/day)
VEST
3833 Vesnarinone (30 or 60 mg/day)
PROFILE[
2304 Flosequinan (75-100 mg/day)
FIRST
471 Epoprostenol (median 4ng/kg/min)
Table I. Double-blind, randomized clinical trials on drugs associated with a statistically
significantly increased risk of mortality in patients with congestive heart failure.
Regardless of the pharmacological differences among agents such as xamoterol,
milrinone, flosequinan and ibopamine, their ultimate effect on survival in patients with
congestive heart failure can only be considered as unfavourable. Despite the inability of these
drugs to exert favourable or even neutral effects on survival in patients with congestive heart
failure, many of them may improve exercise tolerance and relieve symptoms. This raises the key
question as to whether we are willing to accept improved quality of life at the expense of
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decreased survival, assuming that both the beneficial effect on quality of life and the
unfavourable effect on survival of the drug involved have unequivocally been demonstrated.
Improvement in quality of life and prolongation of life expectancy (quantity of life) are
the main objectives in the treatment of patients with congestive heart failure. Some of the newer
treatments of congestive heart failure have been shown to improve quality of life at the expense
of increased mortality. When treating an individual patient with congestive heart failure,
physicians should decide on the primary aim of the treatment for that specific patient.
This actually implies a translation of state of- the-art knowledge on safety and quality of
life issues into a therapeutic approach in which all the relevant patient characteristics are also
taken into account. Of course, the patient must play an important role in this decision process.
Obviously, an increased risk of mortality in a clinical trial does not necessarily mean that an
individual patient with congestive heart failure will die earlier. Likewise, an average
improvement of quality of life in a clinical trial does not necessarily mean that every individual
patient will experience relief of symptoms.
Use of drugs which have been demonstrated to decrease survival in patients with
congestive heart failure can only be accepted, however, when the probability of improvement of
quality of life and prolongation of life expectancy for those using the drug exceeds the
probability of improvement of quality of life and prolongation of life expectancy for those not
using the drug. In table II, the intention- to-treat analysis of exercise capacity data from the
imobendan in Congestive Heart Failure (PICO) trial demonstrates that, despite a trend towards
higher mortality in patients started on pimobendan, this probability is larger for those using the
drug (63%) as compared to those not using the drug (59%).
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Congestive Heart Failure
Unfortunately, only few clinical trials in which both survival and (aspects of) quality of
life were evaluated offer the possibility for such a comparison.
Parameter
Exercise capacity
improved
No. of pimobendan
patients
(%)
maintained
or
64 (59)
132 (63)
34 (31)
48 (23)
4 (4)
5 (2)
6 (6)
24 (12)
108
(100)
209 (100)
Exercise capacity deteriorated
Too sick to exercise
Dead
Total
Table II. Intention-to-treat analysis of exercise capacity after 24 weeks of treatment with
pimobendan 2.5 to 5mg or placebo. Data adapted from the Pimobendan in Congestive Heart
Failure (PICO) trial
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Congestive Heart Failure
Conclusion
Epidemiology can seem like a difficult process but when broken down into steps, can be
used by many. Nurses can use the process to find causes Using epidemiology to help treat CHF
is helpful to patients and caregivers of symptoms in their patients.. Finding the root cause is
imperative in treating any disease. Preventing the disease is our first preference but in many
cases heart failure cannot be prevented. Treating it is the second best way to stop the disease
from worsening.
Improvement of life expectancy and quality of life are both mainstays of congestive heart
failure treatment. drugs which improve quality of life at the expense of an increased risk of
mortality can be of value in the treatment of patients with severe congestive heart failure,
provided that the probability of improvement of quality of life and prolongation of life
expectancy for those using the drug exceeds the probability of improvement of quality of life and
prolongation of life expectancy for those not using the drug. Appropriate treatment in these
patients may imply that relief of symptoms becomes the primary aim instead of prolongation of
life expectancy. Based on this risk benefit profile, clinicians will be able, in dialogue with their
patients, to choose the most appropriate treatment available.
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Congestive Heart Failure
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