In which patients is hydralazine–isosorbide dinitrate recommended, and what benefit was shown?

• A. Black patients with HFrEF (NYHA III-IV) or those intolerant to ACE inhibitors; improved survival
• B. All patients with HF regardless of race; immediate symptom relief
• C. Patients with preserved EF; improved ejection fraction
• D. Only patients post-MI; reduces reinfarction rate

Answer: (A)

The main idea is that hydralazine–isosorbide dinitrate provides a mortality benefit when added to standard therapy specifically in Black patients with heart failure due to reduced ejection fraction who are NYHA class III–IV (or who cannot take ACE inhibitors). Mechanistically, hydralazine dilates arteries, lowering afterload, while isosorbide dinitrate dilates veins, reducing preload. Together they improve forward cardiac output and reduce the workload on a failing heart, which translates into improved survival in this population. This benefit has been demonstrated in Black patients with systolic HF on top of standard therapy; it isn’t shown to have the same mortality advantage in HF with preserved EF or when used universally in all HF patients. It’s intended to be added to guideline-directed medical therapy, particularly for those who cannot tolerate ACE inhibitors.