What is the role of vasodilators in chronic heart failure? Who should receive them?

There are three main groups of vasodilator therapies used in the treatment of chronic heart failure.

Nitrates alone
Nitrates on their own can be used intermittently for relief of dyspnoea – not well documented, but logical to try. For example, intermittent sublingual or oral nitrates may benefit a patient already on high doses of loop diuretics and an ACE inhibitor, but who still has severe exertional or nocturnal dyspnoea, and needs relief. The continuous use of nitrates does, however, run the risk of nitrate tolerance, which in turn may be lessened by combination with hydralazine.

Nitrates plus hydralazine
Nitrates plus hydralazine are better than placebo in chronic heart failure, although inferior to ACE inhibitors. They therefore represent treatment options when the patient experiences ACE intolerance, although the drugs of choice for this situation would be the angiotensin receptor blockers.

The long-acting dihydropyridines (DHPs, e.g. amlodipine and felodipine)
Regarding the calcium blockers, the non-DHPs are contraindicated whereas the long acting DHP amlodipine has suggestive benefit on mortality in non-ischemic cardiomyopathy, as shown in the PRAISE study.2 In the ischaemic patients, the drug was safe yet without any suggestion of mortality benefit. Hypothetically, part of the benefit in dilated cardiomyopathy could be by inhibition of cytokine production,3 and not by vasodilatation. PRAISE 2 is focusing on non-ischaemic cardiomyopathy
patients. In the meantime, long acting DHPs such as amlodipine or felodipine may be cautiously added when heart failure patients still have angina that persists after nitrates and beta blockade, or hypertension despite ACE inhibitors, beta blockers and diuretics. Yet with the convincing evidence for real benefits from beta blockade in heart failure, the DHPs should probably only be used, even for these limited indications, if beta blockade is contraindicated.

The inotropic dilators (“inodilators”) such as amrinone and milrinone are very useful in acute heart failure, but are not safe in chronic heart failure, as warned by the FDA because of the risks of increased hospitalisation and mortality.