How is Prinzmetal's angina diagnosed?
Prinzmetal's angina is often diagnosed with an ECG (electrocardiogram or EKG) during an episode of chest pain. The ECG may show a particular pattern called ST-segment elevation—a bump on a graph of the heart's electrical activity that shows up in a telltale place. The pattern will disappear when the chest pain resolves. If you do not have heart disease (meaning an X-ray of your heart shows no major blockages in the arteries of your heart) or have only mild heart disease, and this pattern appears during ECG testing, you will probably be diagnosed with a Prinzmetal's angina. If you have heart disease, this particular ECG pattern is may indicate that you are having a heart attack.
The gold standard for confirming a diagnosis of Prinzmetal's angina is the coronary angiogram, a test that produces an X-ray of the heart's arteries on a monitor. The physician will give you medication to see if it induces a spasm (the spasm will be visible on the monitor). If a focal spasm (a spasm at just one spot, rather than all over) occurs and you have ST-segment elevation on an ECG, you have Prinzmetal's angina.
How is Prinzmetal's angina treated?
Prinzmetal's angina is treated with medications, specifically nitroglycerin (NTG), long-acting nitrates, and calcium channel blockers — all of which widen or open the blood vessels and improve blood and oxygen flow to the heart muscle. Calcium channel blockers are generally prescribed first. If you continue to experience episodes of chest pain, then a different class of calcium channel blocker or a long-acting nitrate may be given. For people who do not respond well to either of these drugs, alpha blockers can be prescribed. Alpha blockers lower blood pressure and reduce blood vessel narrowing by blocking the action of stress hormones. Nitroglycerin is used when you are experiencing a spasm to stop it, thereby alleviating pain; it is not used as a preventive medication. Nitroglycerin is usually given as a spray that you use in your mouth or a tablet that you place under your tongue.
Risk factor modification is also important because most people with Prinzmetal's angina also have heart disease and are therefore at risk for a heart attack. It is especially important to stop smoking because smoking increases the likelihood of coronary artery spasms.5 By lowering your risk factors, you will reduce your chances of developing atherosclerosis. In addition, people diagnosed with Prinzmetal's angina should avoid exposure to cold and high stress situations since these can trigger spasms.
What is the prognosis for people with Prinzmetal's angina?
With medication, the prognosis is very good for people with Prinzmetal's angina, and their chest pain can be treated successfully. One study found that 97% of patients survived 5 years after being diagnosed with Prinzmetal's angina, and 83% survived without having a heart attack.8 Another study of 202 patients (18% female) who were diagnosed with variant angina between 1991 and 2002 found that 80% survived without a heart attack, and that most negative events happened within a month of when the patient first started having symptoms.9
Prognosis is closely tied to the extent of coronary artery disease, and people with more severe heart disease have worse outcomes than those with less severe or no heart disease.10 The severity of the spasm, and how completely it blocks blood flow to the heart, may also predict outcomes: in one study, people who had ST-elevation on an ECG were 3 times as likely to die or have a heart attack than those who did not, independent of the extent of their coronary artery disease.9 Variant angina also increases the risk of developing a cardiac arrythmia (heart rhythm disorder), and there is a small but significant risk of sudden cardiac death. Sudden cardiac death occurs most often in people who have spasm in multiple arteries and have experienced an arrhythmia before during a chest pain attack.11
References
1. Braunwald E, Antman EM, Beasley JW, et al. ACC/AHA 2002 guideline update for the management of patients with unstable angina and non-ST-segment elevation myocardial infarction--summary article: a report of the American College of Cardiology/American Heart Association task force on practice guidelines (Committee on the Management of Patients With Unstable Angina). J Am Coll Cardiol. Oct 2 2002;40(7):1366-1374.
2. Ogawa H, Yasue H, Oshima S, Okumura K, Matsuyama K, Obata K. Circadian variation of plasma fibrinopeptide A level in patients with variant angina. Circulation. Dec 1989;80(6):1617-1626.
3. Orford JL, Selwyn A. Coronary artery vasospasm. emedicine.com, Inc. [html]. January 30, 2004. Available at: http://www.emedicine.com/med/topic447.htm. Accessed June 1, 2004, 2004.
4. Beltrame JF, Sasayama S, Maseri A. Racial heterogeneity in coronary artery vasomotor reactivity: differences between Japanese and Caucasian patients. J Am Coll Cardiol. May 1999;33(6):1442-1452.
5. Nobuyoshi M, Abe M, Nosaka H, et al. Statistical analysis of clinical risk factors for coronary artery spasm: identification of the most important determinant. Am Heart J. Jul 1992;124(1):32-38.
6. Kawano H, Motoyama T, Hirai N, Kugiyama K, Ogawa H, Yasue H. Estradiol supplementation suppresses hyperventilation-induced attacks in postmenopausal women with variant angina. J Am Coll Cardiol. Mar 1 2001;37(3):735-740.
7. Kawano H, Motoyama T, Ohgushi M, Kugiyama K, Ogawa H, Yasue H. Menstrual Cyclic Variation of Myocardial Ischemia in Premenopausal Women with Variant Angina. Ann Intern Med. 2001;135(11):977-981.
8. Yasue H, Takizawa A, Nagao M, et al. Long-term prognosis for patients with variant angina and influential factors. Circulation. Jul 1988;78(1):1-9.
9. Lanza GA, Sestito A, Sgueglia GA, et al. Current clinical features, diagnostic assessment and prognostic determinants of patients with variant angina. Int J Cardiol. May 16 2007;118(1):41-47.
10. Rovai D, Bianchi M, Baratto M, et al. Organic coronary stenosis in Prinzmetal's variant angina. J Cardiol. Dec 1997;30(6):299-305.
11. Orford JL, Selwyn AP. Coronary artery vasospasm. www.emedicine.com [html]. November 8, 2005. Available at: http://www.emedicine.com/med/topic447.htm, 2007.
