Heart Failure: Types and Treatments

Heart Failure Statistics:

An estimated 4.8 million Americans have been diagnosed with heart failure. This is equivalent to about 1 in every 56 Americans. Every year a record 500,000 new cases are being reported. Heart failure is more prevalent in the elderly. An alarming 10% of all elderly patients over the age of 75 are affected by some type of heart failure. The United States spends approximately $25-$40 billion dollars each year to care for this patient population. In addition, every year over 11 million patients with heart failure will visit their family doctor and a record 3.5 million will become hospitalized. Of the hospitalized group, one third will be readmitted within three months. This makes the cost of heart failure hospitalizations twice the amount spent in treating patients with cancer.

Types of Heart Failure

There are a wide variety and many types of heart failure, including failures that are related to the structure of the heart’s valves or breakdown in function due to changes and weakening of the heart muscle. Heart failure can also be attributed to various diseases. The following are brief descriptions of the most common forms of failure.

1. Valvular

Regurgitation - Leaking of valves resulting in backward flow of blood in the heart chambers. As a result, the heart has to compensate for this added workload. The heart dilates and eventually the heart muscle weakens.
Stenosis - Narrowing of valves. The heart chamber behind the narrowed valve has to work harder. The heart muscle of this chamber weakens as a result.

2. Cardiomyopathy -

Weakening of the heart muscle or a change in the muscle structure.

Dilated Cardiomyopathy - Usually Idiopathic. The heart becomes weakened and enlarged. This is the most common form of cardiomyopathy. It is most common in men with heart failure affecting 2 in 100.
Ischemic Cardiomyopathy - It is caused by coronary artery disease (CAD). This is the most common type of heart failure in the U.S., affecting 1 in 100 people with heart failure. Most common in middle age elderly men.
Hypertensive Cardiomyopathy - Longstanding, untreated hypertension causes thickening of the heart muscle and eventual dilation.
Peripartum Cardiomyopathy - Occurs during last trimester of pregnancy or within 5 months of delivery.
Alcoholic Cardiomyopathy - A form of dilated cardiomyopathy that occurs as a result of longstanding alcohol abuse and is usually associated with rhythm problems.
Infectious Cardiomyopathy - Associated with HIV, Viral Myocarditis, Lyme disease and Chagas Disease.
Restrictive Cardiomyopathy - also referred to as Infiltrative Cardiomyopathy. Affects heart muscle and its ability to relax between contractions. Myocardium becomes fibrous. The heart tends to be normal in size or only slightly enlarged.
Hypertrophic Cardiomyopathy - also referred to as Asymmetric Septal Hypertrophy (ASH), hypertrophic obstructive cardiomyopathy (HOCM), and idiopathic hypertrophic subaortic stenosis (IHSS). Tends to be familial. Causes asymmetry in the ventricular chambers usually affecting the left ventricle and the septum. Occurs in young adults.

3. Congestive heart Failure (CHF) -

Failure of the heart to perform effectively and adequately. As the heart fails, other organs are affected, especially the kidneys which lose their ability to excrete salt and water. The lungs eventually become fluid overloaded as in pulmonary edema. The liver can also lose its ability to excrete toxins. Over time, all organs become affected in some way. The most common causes of CHF in the U.S. are coronary artery disease (CAD), hypertension, alcohol abuse, valvular disease, viral infection of the myocardium, rhythm disorders, and drug induced.

Right Heart Failure -
The right side of the heart is unable to pump blood efficiently. This normally occurs as a result of tricuspid regurgitation (TR), right- ventricular (RV) infarct, pulmonic stenosis (PS) and pulmonary hypertension.

Left Heart Failure -
The left side of the heart cannot pump enough blood to the body. This condition can be life threatening and normally occurs as a result of left ventricular (LV) dysfunction or aortic stenosis.

Systolic Heart Failure -
Difficulty pumping.

Diastolic Heart failure -
Difficulty with expansion and inadequate filling due to stiffness of the heart muscle.

4. Coronary Artery disease (CAD) -

Also known as coronary heart disease (CHD). The narrowing of the coronary arteries as a result of fatty material and plaque build up.

5. Congenital Heart Disease -

An abnormality in heart structure and function. This abnormality occurs during the heart development before birth but is present at birth.

6. Family History -

A family history of enlarged hearts.

Classification of Heart Failure:

According to the New York Heart Association (NYHA), heart failure patients can be classified into 4 groups based on symptoms.

Class I - Patients have risk factors but no symptoms.
Class II - Patients may have some underlying cardiac history and may have symptoms with very moderate exertion.
Class III - Patients have known cardiac history and previous heart failure symptoms with medication. Patients have symptoms with very minimal exertion.
Class IV - Patients require bridge devices like left ventricular assist devices (LVADs), heart transplant or palliative treatment. Patients have symptoms at rest.

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Treatment of Heart Failure:

I. Medical Therapy -

Positive Inotropes - Increase myocardial contraction.
Diuretics - achieve a euvolemic state by removing more sodium and water from the body in the form of urine. Examples include Lasix and Spironolactone.
Vasodilators - relax blood vessels allowing for increase in flow
Angiotensin -converting enzyme (ACE) inhibitors and Angiotensin Receptor Blockers (ARB) prevent the body from making angiotensin which causes vessels to tighten, thus increasing blood pressure. These medications cause vessels to dilate, allowing increased flow, decreasing blood pressure and ultimately decreasing the heart’s workload.
Aldosterone Blockers - work on hormones in the blood stream like aldosterone, causing an increase in salt and water excretion. The drugs also lower blood pressure and thus decrease the heart’s workload.
Beta Blockers - decrease heart rate, primarily block beta receptors and sometimes can block alpha and beta receptors (mixed antagonism) allowing arteries to expand, decreasing resistance, lowering blood pressure and reducing arrhythmias. Heart failure causes an increase in levels of norepinephrine, which causes heart remodeling. Beta blockers act on these beta receptors reducing this effect.
Digoxin - increases muscle strength and slows heart rate. The most common indication for Digoxin is to treat atrial fibrillation and atrial flutter with fast ventricular response
Other Medications, including blood thinners and antiarrhythmics. Blood thinners decrease the risk of stroke and antiarrhytmics treat arrhythmias

II. Device Therapy -

Biventricular Pacemaker with Defibrillation – Cardiac resynchronization therapy (CRT) is a proven treatment option for patients with heart failure. It maintains heart rate and allows the left and right ventricle to contract at the same time. If combined with defibrillation, it also terminates deadly arrhythmias. A pacemaker (Medtronic Corporation) is shown in Figure 1.

Left ventricular assist device (LVAD) - Used as a bridge to transplant. It assists the weakened ventricle by pulling blood from the left ventricle and sending it to the aorta via the pump. LVADs are portable and patients can be discharged to home (Also known as destination therapy). An implantable LVAD, the Heart Mate II (Thoratec Corporation) is shown above. The HeartMate II is implanted in the chest to support the heart’s pumping function. An external, belt-worn system controller and battery are attached to the implanted pump via a thin, flexible percutaneous cable. Refer to Figure 2.

temporary Total Artificial Heart (TAH-t) -
The modern version of the Jarvik-7 artificial heart, which was first implanted in 1982. The first temporary Total Artificial Heart manufactured by CardioWest (SynCardia Systems, Inc.) was recently transplanted at the University of Pennsylvania Hospital. Research studies suggest that patients receiving the TAH-t have almost twice the survival rate of patients receiving the ventricular assist devices.

To implant the TAH-t the patient’s heart is removed and replaced with the artificial heart. The TAH-t is the only total artificial heart currently approved by the U.S. FDA, Health Canada, and Communite Europeenne as a bridge device to transplant.

Refer to figures 3 and 4 for examples of a temporary artificial heart, and figures 5 and 6 for a patient recovering after surgery.

Total Implantable artificial heart

The AbioCor device, a total implantable artificial heart manufactured by ABIOMED was first implanted in 2001. It was approved by the FDA in 2006 as a humanitarian device. A disadvantage is its size, which is presently compatible only with males with larger frames. The current device has a life expectancy of about 18 months.

An AbioCor II device is schedule for human trials in 2008. The new model will be smaller in size, making it more universal for both men and women. There also has been modification to decrease the risk of stroke which is a concern of the FDA. Life expectancy of the AbioCor II is projected to be about 5 years.

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Heart Failure Patients

As noted earlier, patients with heart failure are a growing part of the patient population in electrophysiology and cardiac catheterization labs. These patients usually present with symptoms that include but are not limited to shortness of breath (SOB), edema, hypotension, orthopnea, arrhythmias, and ascites.

In a cath lab setting patients sometimes undergo a right and left heart catheterization. Hemodynamic analysis and coronary angiography are especially important in diagnosis and treatment.

From a hemodynamic standpoint, right heart pressures, left ventricular end diastolic pressure (LVEDP), cardiac output and cardiac index are used along with a pulmonary artery oxygen saturation as guides in determining, classifying and treating these patients.

For example: if the pulmonary capillary wedge pressure (PCWP) is greater than 18 mmHg, the physician may choose to leave an indwelling Swan-Ganz catheter for monitoring. If the catheter is left in, the patient is normally transferred to a unit with nursing staff trained to care for these patients.

Physicians may choose not to do an elective left heart cath with coronary angiography in a patient in severe failure, primarily because heart failure patients often suffer from renal failure. In an effort to minimize any further damage to the kidneys from contrast agents, elective procedures are often avoided in these patients.

Coronary angiography gives the interventional cardiologist the option to treat any blockages s/he concludes are culprits. Once again, the physician may opt to “tune up” the patient before proceeding with any elective procedures. It is important to remember that treating the underlying cause can sometimes make heart transplantation a future treatment option and not an immediate choice.
In the electrophysiology lab setting, heart failure patients are often referred for biventricular cardiac resynchronization therapy (CRT)/ implantable cardioverter defibrillator (ICD) insertions. CRT is often recommended in patients with an ejection fraction < 35%, QRS>120msec, NYHA Class III or Class IV despite maximum medical therapy. Patients present with the same symptoms described earlier.

Heart Transplantation

Definition: A surgical transplant procedure in which a damaged or failing heart is removed and replaced with a donor heart. This is usually performed on patients with end- stage heart failure or severe coronary artery disease.

Heart transplantation has become the treatment of choice for many patients with severe heart failure who have failed maximum medical therapy. Survival rates have improved over the last 30 years, due primarily to advancements in the treatment of post transplant infections, and drug therapy with immunosuppressants.

Heart transplant patients are generally under the age of 70 and do not have irreversible damage to other organs. A major problem facing patients in need of heart transplantation today is the shortage of donor hearts.

History: The first human heart transplant was performed in 1967 in South Africa by Christian Barnard. In 1968 the first heart transplant was performed in the U.S. by Norman Shumway.
However, the survival rate during the first year post-transplant was documented to be approximately 15%. This low survival rate was primarily due to the inability to treat rejection with the immunosuppresion drugs available at that time.

In 1981 Robert Jarvic developed the first artificial heart. In 1982 the first artificial heart implant procedure was performed by Dr. William Devieres. The patient survived only 112 days.

In 1984 a new born baby known as Baby Fae was transplanted using a baboon heart. Baby Fae only survived for a few days.

Statistics:

Heart transplant survival results as of August 2006 are as follows:

• 1 year: Males—86.1% Females—83.9%

• 3 years: Males—78.3% Females—74.9%

• 5 years: Males—71.2% Females—66.9%

• Two to three episodes of rejection occur in the first year.

• Acute rejection occurs in the first three to six months.

• Most deaths in the first year are due to acute rejection (18%) or infections (22%).

• Four thousand patients each are in need of cardiac transplantation every year, but only about 2,000 organs become available.

• Heart transplantation is the fourth most common transplant surgery in the U.S.

There are four types of transplant procedures:

1. Orthotopic: The left atrium and pulmonary vein of patient’s original heart are left in place.
2. Heterotropic: The patient’s original heart is not removed resulting in what is referred to as a “double heart”. The original heart is in a state of rest, with hopes of healing and overcoming heart failure.
3. Xenograft: A heart from another species. This procedure was performed on Baby Fae with a baboon heart. Recent research has shown advancements, with porcine (pig) transplant possible for humans in the future.
4. Artificial Heart: A man made heart. As noted above, there have been some technological advancements with the Jarvic heart (1981).

Treatment post-transplant:

The body sees the transplanted heart as foreign tissue. Without immunosupressants, the body attacks the organ as it would an infection.

Cardiac endomyocardial biopsies are performed frequently to check for rejection. Rejections are known to occur in the first weeks and months after transplant. The frequency of biopsy decreases over time.

Drug therapy continues, even though fewer antisuppressants may be needed over time. The patient’s immune system activity is suppressed, making him/her more prone to infections. Patients are sometimes prescribed anti-bacterial, antiviral and antifungal drugs to help prevent infections.

The transplanted organ can also experience heart failure due to rejection, valvular disease or coronary artery disease. If this occurs, the patient could possibly be re-transplanted or the drug therapy modified.

Endomyocardial Biopsy:

The risk of developing rejection is usually highest immediately after transplant. About 40% of new transplant patients will have at least one rejection during the first year post transplant with 85% of all rejections classified as “cellular rejection”.
An endomyocardial biopsy is normally performed post transplantation, although it is sometimes performed on patients who have not undergone transplant.
For non transplant patients, a biopsy is done in order to help with clinical diagnoses. Refer to figure 7.

A biopsy is done by placing a sheath in the internal jugular vein or femoral vein. A bioptome is then used to remove small pieces of heart tissue from the right ventricle for analysis. Tissue analysis is used to check for rejection post transplant.

Rejection:

The International Heart and Lung Transplantation Society (IHLTS) grading scale is used to measure rejection of transplanted hearts.
1. Grade 1A and 1B: mild rejection. Heart tissues usually show signs of interstitial inflammation. There is no myocyte necrosis. Mild rejection is often not treated with immunosuppressant. Patients are usually stable and their medications adjusted.
2. Grade 2: Patients are also stable. Drug doses are normally increased and steroids added. The dose is 100mg TID and usually this dose can vary for different individuals.
3. Grade 3 and 4: Moderate/severe rejection. Patients are treated with augmented immunosuppressant. Grade 3A/3B rejection normally shows increase in central venous pressure (CVP) and pulmonary capillary wedge pressure (PCWP), a decrease in ejection fraction (EF) and an increase in arrhythmias. Patients are usually given more steroids and anti-rejection treatment, such as ORTHOCLONE OKT®3 (muromonab-CD3). This type of aggressive treatment is normally used for a grade 3B or grade 4 rejections.

The Future of Heart Transplant:

Heart transplant and treatment continue to evolve. Currently, the only way to monitor and treat rejection is by doing an endomyocardial biopsy. With technological advancements and research studies, other alternatives are being investigated.

The CARGO (Cardio Allograft Rejection Gene Expression Observational) trial, for example, is investigating the use of blood tests as the tool to monitor rejection. A test called AlloMap looks for the activation of genes proven to be associated with rejection.

The Tailored Immunosuppressant Therapy study is protocol based and makes use of tissue typing and individual risk profiles. The current treatment protocol is one in which every patient gets the standard immunosuppressant treatment. Tailored Immunosuppressant Therapy takes an in-depth look at each patient and generates a specific treatment regimen.

Groups identified as high risk prior to transplantation should continue to be monitored closely post transplant and be considered for this type of treatment.

These high risk groups include:

• Younger females of African American race

• Donors older than 50

• Re-transplants

• Patients with high levels of preformed antibodies (PRA).

• Patients with delayed graft function.

Immunosuppressant therapy should be tailored so that patients in a high risk group receive higher doses and more intensive treatment.

Conclusion

Although research and technological advancements continue in the heart failure /heart transplantation arena, healthcare workers must continue to be patients’ advocates. Education should be made available to patients on the severity of heart failure, and the potential problems and end results if the condition is left untreated.
Continuous and close monitoring is recommended for patients diagnosed with heart failure. Patients should be referred to a heart failure group where they can be evaluated and early treatment options utilized to minimize progression of the condition. As noted earlier, early diagnosis and treatment can postpone and even prevent the need for the least favored treatment option of heart transplantation.

References

• Billingham ME. Diagnosis of cardiac rejection by endomyocardial biopsy. J Heart Transplant 1982; 1:25-30.

• Cattaneo, Dario; Perico, Norberto; Remuzzi, Giuseppe. From Pharmacokinetics to Pharmacogenomics: A New Approach to Tailor Immunosuppressive Therapy. American Journal of Transplantation, Volume 7, Number 9.

• Dressler, Diane K., RN, MSN, CCRN, CCTC Organ Transplantation: Concepts, Issues, Practice, and Outcomes. Organ Transplant 2002

• Tuma, Rabiya S., PhD Molecular Test Supports Weaning From Immunosuppressants. Medscape Medical News 2007.

• www.americanheart.orgwww.Wikipedia.org