Pathophysiology of heart failure in African Americans
In addition to modifiable and socioeconomic risk factors, scientific evidence supports that there may be different patterns of disease progression that impact the way different ethnic groups experience heart failure (HF). Data show that normotensive African American patients have less elastic small arteries than white or Chinese patients. The underlying mechanisms associated with this vascular dysfunction in African Americans may be related to1
- Decreased nitric oxide (NO) availability
- Increased oxidative stress
- Exaggerated vasoconstrictor response
These biologic differences may have the potential to influence how African Americans respond to pharmacologic intervention for HF compared with other ethnic groups. Many standard-of-care medications may have different results in African Americans than in whites, as demonstrated by subgroup analyses of clinical trials.1
Etiology of HF in African American and white patients2,3
LVH=left ventricular hypertrophy; MI=myocardial infarction.
Recommended HF treatments and their effects in African American patients vs white patients1
|Digoxin||May be less effective in African Americans|
|Angiotensin-converting enzyme (ACE) inhibitors||Insufficient evidence except for enalapril, which shows similar benefit|
|Angiotensin receptor blockers (ARB)||Insufficient evidence|
|Beta-blockers||Bucindolol may be less effective in African Americans; carvedilol shows similar benefit, and metoprolol XL has insufficient evidence|
|Aldosterone antagonists||Insufficient evidence|
|Hydralazine and isosorbide dinitrate||Effective in African Americans|
|Implantable cardioverter-defibrillators||Similar benefit|
|Chronic resynchronization therapy||Insufficient evidence|
|Heart transplantation||African Americans have lower survival rates|
|Left ventricular assist devices||Comparable survival rates|
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IMPORTANT SAFETY INFORMATION
BiDil is contraindicated in patients who are allergic to organic nitrates, or who take a phosphodiesterase type 5 (PDE5) inhibitors, such as avanafil, sildenafil, tadalafil, or vardenafil, or soluble guanylate cyclase (sGC) stimulator (riociguat). Concomitant use can cause hypotension.
INDICATIONS AND USAGE
BiDil is indicated for the treatment of heart failure as an adjunct to standard therapy in self-identified black patients to improve survival, to prolong time to hospitalization for heart failure, and to improve patient-reported functional status. There is little experience in patients with NYHA class IV heart failure. Most patients in the clinical trial supporting effectiveness (A-HeFT) received a loop diuretic, an angiotensin converting enzyme inhibitor or an angiotensin II receptor blocker, and a beta blocker, and many also received a cardiac glycoside or an aldosterone antagonist.
IMPORTANT SAFETY INFORMATION
BiDil is contraindicated in patients who are allergic to organic nitrates, or who take phosphodiesterase type 5 (PDE5) inhibitors, such as avanafil, sildenafil, tadalafil, or vardenafil, or soluble guanylate cyclase (sGC) stimulator (riociguat). Concomitant use can cause hypotension.
WARNINGS AND PRECAUTIONS
Hydralazine hydrochloride has been reported to cause a drug-induced systemic lupus erythematosus (SLE) syndrome. Symptoms and signs usually regress when hydralazine hydrochloride is discontinued.
Symptomatic hypotension, particularly with upright posture, may occur with even small doses of BiDil. Hypotension is most likely to occur in patients who have been volume or salt depleted; correct prior to initiation of BiDil. Hydralazine hydrochloride can cause tachycardia and hypotension potentially leading to myocardial ischemia and angina, particularly in patients with hypertrophic cardiomyopathy.
Hydralazine hydrochloride has been associated with peripheral neuritis, evidenced by paresthesia, numbness, and tingling, which may be related to an antipyridoxine effect. Pyridoxine should be added to BiDil therapy if such symptoms develop.
Most common adverse reactions (> 5% more on BiDil than on placebo) were headache and dizziness.
References: 1. Sharma A, Colvin-Adams M, Yancy CW. Heart failure in African Americans: Disparities can be overcome. Cleve Clin J Med. 2014;81(5):301-311. 2. Yancy CW. Heart failure in African-Americans. US Cardiol. 2006;2005:2(1):196-200. 3. Yancy CW. Heart failure in African Americans: unique etiology and pharmacologic treatment responses. J Natl Med Assoc. 2003;95:1-12.