From the Guidelines
Prinzmetal angina should be treated with calcium channel blockers and nitrates as first-line therapy, with the goal of reducing morbidity, mortality, and improving quality of life. The treatment of Prinzmetal angina focuses on relieving symptoms and preventing complications, with calcium channel blockers like diltiazem (180-360 mg daily) or amlodipine (5-10 mg daily) being the primary treatment option, as recommended by the American College of Cardiology Foundation/American Heart Association task force on practice guidelines 1.
Key Considerations
- Beta-blockers should be avoided as they can worsen coronary spasms, and patients should immediately stop smoking, as tobacco is a major trigger for vasospasm 1.
- During acute attacks, sublingual nitroglycerin (0.4 mg) provides rapid relief, and long-acting nitrates such as isosorbide mononitrate (30-60 mg daily) can be added for additional relief 1.
- The underlying mechanism of Prinzmetal angina involves hyperreactivity of vascular smooth muscle in coronary arteries, leading to inappropriate vasoconstriction that temporarily restricts blood flow to heart muscle, and it can lead to serious complications including arrhythmias, myocardial infarction, or sudden cardiac death if left untreated 1.
Diagnostic Approach
- Diagnostic investigation is indicated in patients with a clinical picture suggestive of coronary spasm, with investigation for the presence of transient myocardial ischemia and ST-segment elevation during chest pain, as recommended by the American College of Cardiology Foundation/American Heart Association task force on practice guidelines 1.
- Coronary angiography is recommended in patients with episodic chest pain accompanied by transient ST-segment elevation, to rule out obstructive coronary artery disease 1.
Management
- Treatment with nitrates and calcium channel blockers is recommended in patients with variant angina whose coronary angiogram shows no or nonobstructive coronary artery lesions, with risk factor modification being essential to reduce the risk of complications 1.
- Patients with Prinzmetal angina should be closely monitored for signs of complications, and treated promptly if they occur, to reduce morbidity and mortality, and improve quality of life 1.
From the FDA Drug Label
Amlodipine besylate tablets is indicated for the treatment of confirmed or suspected vasospastic angina. Amlodipine has been demonstrated to block constriction and restore blood flow in coronary arteries and arterioles in response to calcium, potassium epinephrine, serotonin, and thromboxane A2 analog in experimental animal models and in human coronary vessels in vitro This inhibition of coronary spasm is responsible for the effectiveness of amlodipine in vasospastic (Prinzmetal's or variant) angina.
Amlodipine is effective in treating Prinzmetal's angina by blocking coronary spasm and restoring blood flow in coronary arteries.
- The drug has been shown to be effective in reducing the frequency of angina attacks in patients with vasospastic angina.
- Amlodipine can be used as monotherapy or in combination with other antianginal agents for the treatment of Prinzmetal's angina 2, 2.
From the Research
Definition and Diagnosis of Prinzmetal Angina
- Prinzmetal's variant angina (PVA) is a form of angina caused by coronary-artery vasospasm (CAS) and is not associated with exertion 3.
- It is diagnosed by history, electrocardiogram, or coronary-artery angiography 3.
- Provocative tests, such as the cold-pressor test or intravenous ergonovine maleate, are sometimes used to aid diagnosis of PVA 3.
Treatment of Prinzmetal Angina
- Nitrates, adrenergic-blocking agents, and calcium-channel blocking agents can be used in treating PVA 3.
- Nitroglycerin and isosorbide dinitrate effectively relieve CAS 3.
- Calcium-channel blocking agents are promising drugs for PVA, with nifedipine being the prototype of this class for antianginal activity 3, 4, 5.
- Diltiazem and verapamil are also effective in preventing episodes of coronary vasospasm and symptoms of ischemia 4, 5.
- Felodipine, a vascular-selective dihydropyridine, has been shown to be effective in treating Prinzmetal's angina, with no negative inotropic effects at clinically administered doses 6.
Combination Therapy
- Therapy using combinations of nitrates, adrenergic-blocking agents, and calcium-channel blocking agents is needed in some patients 3.
- Nifedipine used with beta-blocker drugs is more effective than nifedipine as monotherapy in patients with unstable angina 5.
- A combination regimen of calcium antagonists, beta blockers, and nitrates may be more effective than either form of therapy alone in patients with stable exertional angina 4.
Effectiveness of Calcium Channel Blockers
- Calcium antagonists are highly effective in reducing ischemic episodes in patients with Prinzmetal's angina 4, 5.
- Calcium channel blockers are effective in decreasing episodes of ischemia regardless of the presence or absence of symptoms 4.
- The best responders to calcium antagonist therapy are patients with concentric coronary stenoses 5.