Which drug class predominantly treats angina by dilating blood vessels?

Nitrates are a class of medication that effectively relieve angina by causing vasodilation, which is the widening of blood vessels. This mechanism specifically reduces the workload on the heart by decreasing the amount of blood returning to the heart (preload), which can help to alleviate the chest pain associated with angina. By expanding the blood vessels, nitrates increase blood flow to the heart muscle, ensuring it receives enough oxygen, especially during times of increased demand.

Other drug classes listed, while they have their own uses in cardiovascular health, do not primarily focus on dilating blood vessels to treat angina in the same manner as nitrates. Alpha blockers, for instance, work by blocking alpha-adrenergic receptors, which can lead to vasodilation but are not specifically indicated for angina. ACE inhibitors primarily manage blood pressure and heart failure and may offer protection against some forms of coronary artery disease. Calcium channel blockers can also help reduce angina by relaxing blood vessels and lowering heart rate, but their action is more complex and not as direct in treating angina compared to nitrates. Thus, nitrates remain the mainstay in the acute management of angina through their vasodilatory effects.