Variant angina

Marti V, Guindo J, Valles E, Dominguez de Rozas JM. Angina variante asociada con latanoprost. Med Clin (Bare) 2005 125(6) 238-9. 

VARIANT ANGINA Variant angina results from reduced flow rather than increased demand, and Ca channel blockers have proven efficacy. In these patients, these drugs can attenuate ergonovine-induced vasospasm, suggesting that protection in variant angina is due to coronary dilation rather than to alterations in peripheral hemodynamics. 

Vasospastic angina, variant angina, Prinzmetai s angina Angina precipitated by reversible spasm of coronary vessels... 

Which of the following drugs is considered to be most effective in relieving and preventing ischemic episodes in patients with variant angina ... 

The answer is d. (Hardman, pp 767—775.) Ca channel blockers, of which nifedipine is a prime example, are now considered to be more effective than nitrates in relieving variant angina This is because this type of angina is believed to be caused by vasospasm, which is best antagonized by slow-channel Ca blockers. Such blockers appear to have a relative selectivity for coronary arteries. 

Patients with variant (Prinzmetal s) angina or cocaine-induced ACS may benefit from calcium channel blockers as initial therapy because they can reverse coronary vasospasm. /J-Blockers generally should be avoided in these situations because they may worsen vasospasm through an unopposed /T-blocking effect on smooth muscle. 

Patients with variant or Prinzmetal angina secondary to coronary spasm are more likely to experience pain at rest and in the early morning hours. Pain is not usually brought on by exertion or emotional stress nor is it relieved by rest the electrocardiogram (ECG) pattern is that of current injury with ST-segment elevation rather than depression. 

Because calcium channel antagonists may be more effective, have few serious adverse effects, and can be given less frequently than nitrates, some authorities consider them the agents of choice for variant angina. Nifedipine, verapamil, and diltiazem are all equally effective as single agents for... 

For variant angina, reduction in symptoms and nitroglycerin consumption as documented by a patient diary can assist the interpretation of objective data obtained from ambulatory ECG recordings. Evidence of efficacy includes the reduction of ischemic events, both ST-segment depression and elevation. Additional evidence is a reduced number of attacks of angina requiring hospitalization, and the absence of MI and sudden death. 

The choice between calcium antagonists must take into account the differential effect of nifedipine versus verapamil or diltiazem on cardiac performance (see above). When p-blockers are given, the potential consequences of reducing cardiac contractility (withdrawal of sympathetic drive) must be kept in mind. Since vasodilating P2-receptors are blocked, an increased risk of vasospasm cannot be ruled out Therefore, monotherapy with p-blockers is recommended only in angina due to coronary sclerosis, but not in variant angina. 

Do not give dihydroergotamine to patients with ischemic heart disease (angina pectoris, history of Ml, documented silent ischemia) or to patients who have clinical symptoms or findings consistent with coronary artery vasospasm, including Prinzmetal variant angina. 

Verapamil (Isoptin, Covera), in addition to its use as an antiarrhythmic agent, has been employed extensively in the management of variant (Prinzmetal s) angina and effort-induced angina pectoris (see Chapters 17 and 19). It selectively inhibits the voltage-gated calcium channel that is vital for action potential genesis in slow-response myocytes, such as those found in the sinoatrial and A-V nodes. 

All agents are also effective in the control of variant (Prinzmetal s) angina, in which spasm of the coronary arteries is the main factor. Their usefulness in the more complex unstable (preinfarction) angina is less definite, depending on the hemodynamic status and the susceptibility of the patient to infarction. 

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