Our understanding of congestive heart failure has been rapidly evolving over the past decade. Heart failure is a leading cause of mortality globally and in the US. It is the final end-point of various cardiac diseases. When the cardiac muscles fail, hypertrophy of the cardiac muscle cells is commonly observed. This hypertrophy of cardiomyoctes is a pathological condition leading to hypertension, myocardial infarction, and valvular heart disease as adaption processes. This adaptation to the increased load on the cardiac muscles causes the hypertrophy in order to normalize the stress on the myocardial walls caused by the mechanical overload. Despite this normalization, increased heart mass is correlated with increased morbidity and mortality.
In the US, approximately 5.7 million people suffer from congestive heart failure (CHF). Approximately 50% of patients who are diagnosed with CHF die within five years. It is estimated that CHF costs our country over $30 billion annually. It has been found to vary based on geography and the following chart by the CDC reflects the geographic variation:
What are the risk factors?
- Male sex
- Coronary artery disease
- Sedentary lifestyle
- Diabetes mellitus
- Valvular heart disease
- Lower educational levels
Congestive heart failure (CHF) remains one of the leading causes of hospitalizations in the US and represents a big expenditure of healthcare dollars. A mainstay of treatment is preventing heart failure from developing in the first place through such means as aggressive control of blood pressure and coronary artery disease. Multiple cardiovascular conditions can lead to CHF, including valvular heart disease and dysrhtmmias. It is imperative to manage these conditions aggressively to prevent progression to CHF. Alcohol abuse is a known cause of cardiomyopathy, which can also lead to CHF.
Over the last half century, advancements in the management of cardiac disease have been remarkable. In developed nations, age-adjusted deaths due to cardiovascular factors have decreased by 2/3, including deaths due to myocardial infarction, valvular heart disease, congenital heart disease and many arrhythmias. However, heart failure has not seen the same decline. It is still the most common causes of hospitalization and the number of patients discharged with the primary diagnosis of HF has risen steadily since 1975. It is only in recent years that the numbers in the US and Europe appear to be leveling off and may have slightly decreased. The prevalence of HF increases with age. Over the age of 60 years, 10% of men and 8% of women experience HF. Over three million doctor visits every year are estimated to be due to HF. The annual direct and indirect cost of HF in the US has been estimated to be greater than thirty billion dollars. Despite the great advancements in the treatment of cardiovascular disease, the five year mortality rate remains approximately 50%.
Because CHF is a progressive disease, stages have been delineated to assist in treatment.
The Stages of Heart Failure:
Stage A: Some people also refer to this stage as “pre-heart failure”. In this stage are included people at risk of developing heart failure, including those with hypertension, diabetes, coronary artery disease, metabolic syndrome, history of taking cardiotoxic drugs/medications, history of alcohol abuse, history of rheumatic fever, and family history of cardiomyopathy. Lifestyle modifications are the mainstay of treatment in this stage including exercise, smoking cessation, stopping alcohol and drug abuse, and a healthy diet. ACEI and/or beta-blockers are sometimes prescribed in this stage depending on cardiovascular risk factors.
Stage B: occurs when patients develop structural heart disease that is associated with the development of heart failure but without signs or symptoms of heart failure. In addition to the Stage A treatments, it is recommended that all patients be started on an ACEI or ARB and beta blockers. Additionally, if indicated, surgery should be done for any valvular defects or coronary artery blockages.
Stage C: These patients are known to have systolic heart failure and have active or past symptoms of congestive heart failure. The most common symptoms include dyspnea, fatigue, and decreased exertional ability. All Stage A treatment options should be undertaken. In this stage, all patients should be on ACEI or ARB and beta blocker. If patients are symptomatic, diuretics and digoxin may be prescribed. If symptoms remain severe, an aldosterone inhibitor may be given. Dietary salt and water should be restricted in this stage and the patient’s weight monitored. Any medications that may exacerbate the CHF should be stopped. Some patients may benefit from hydralazine, nitrates, biventricular pacing, or an implantable pacemaker.
Stage D: These patients have systolic heart failure and severe symptoms despite optimal medical management. The treatments for Stages A, B, and C should be continued. Patients should be evaluated to determine if they are candidates for more aggressive treatment such as heart transplant, ventricular assist device, and others or if they are eligible for hospice.
On May 20, 2016, the American College of Cardiology, the American Heart Association, and the Heart Failure Society of America issued new guidelines updating the previous 2013 treatment guidelines. Included in this update is the use of two new medications: angiotensin receptor-neprilysin inhibitor (ABNI), valsartan/sacubitril, and a sinoatrial node modulator, ivabradine. These medications were added to those that can be used for Stage C heart failure (HF) patients with reduced ejection fraction.
Under the new guidelines, a regimen of an ACEI or ARB or ARNI plus a beta-blocker and an aldosterone antagonist is recommended as treatment for patients with chronic symptomatic HF and reduced ejection fraction (EF). When patients are stable with mild to moderate HF and stable blood pressure and are tolerating their medications, consideration should be given to replacing ACIs or ARBS with ARNIs. ARNIs should not be combined with ACIs or used in patients with a history of angioedema. In patients with symptomatic stable chronic HF, Ivabradine may reduce hospitalizations.
Many research studies are on-going regarding HF, looking for predictors to disease as well as genetic factors and treatments to many factors in between. In one study published August 2016, a group of researchers at the University of Texas Health Science Center at Houston identified powerful predictors of HF. They studied the way certain gene mutations affect metabolites circulating in the body. They found a mutated gene, SLCO1B1, was associated with high levels of circulating fatty acids. They also found that this mutation had a direct effect on HF risk as well.
Another study attempted to use stem cells to promote heart repair and its effects on CHF. The findings of the CHART-1 trial, however, did not show significant improvement in the outcome of Congestive Heart Failure. There was, nonetheless, a subgroup of patients who had severe heart enlargement at baseline who did show a positive response with the stem cell treatment. Clearly, more investigation is needed.
Despite the fact that many studies are on-going, HF remains a major cause of morbidity and mortality as well as expenditure of healthcare dollars. As our population continues to grow older, we can expect these numbers to worsen unless something changes. Certainly, more studies are needed to impact the outcome of this disease.