Page 208 - Basic _ Clinical Pharmacology ( PDFDrive )

12 Vasodilators & the
C H A P T E R

Treatment of

Angina Pectoris

*
Bertram G. Katzung, MD, PhD

C ASE STUD Y

A 56-year-old woman presents in the office with a history of attack” at age 55, and an uncle died of some cardiac disease
recent-onset chest discomfort when jogging or swimming at age 60. On physical examination, the patient’s blood
vigorously. The pain is dull but poorly localized; it disap- pressure is 145/90 mm Hg, and her heart rate is 80 bpm.
pears after 5–10 minutes of rest. She has never smoked but She is in no acute distress, and there are no other significant
has a history of hyperlipidemia (total cholesterol level of physical findings; an electrocardiogram is normal except for
245 mg/dL and low-density lipoprotein [LDL] of 160 mg/dL slight left ventricular hypertrophy. Assuming that a diagno-
recorded 1 year ago) and admits that she has not been fol- sis of stable effort angina is correct, what medical treatment
lowing the recommended diet. Her father survived a “heart should be implemented?

Ischemic heart disease is one of the most common cardiovascular transient spasm of localized portions of these vessels, usually
diseases in developed countries, and angina pectoris is the most associated with underlying atheromas, can also cause significant
common condition involving tissue ischemia in which vasodilator myocardial ischemia and pain (vasospastic or variant angina).
drugs are used. The name angina pectoris denotes chest pain caused Vasospastic angina is also called Prinzmetal angina. Diagnosis is
by accumulation of metabolites resulting from myocardial ischemia. made on the basis of history.
The organic nitrates, eg, nitroglycerin, are the mainstay of therapy The primary cause of angina pectoris is an imbalance between
for the immediate relief of angina. Another group of vasodilators, the the oxygen requirement of the heart and the oxygen supplied to
calcium channel blockers, is also important, especially for prophy- it via the coronary vessels. In effort angina, the imbalance occurs
laxis, and β blockers, which are not vasodilators, are also useful in when the myocardial oxygen requirement increases, especially
prophylaxis. Several newer drugs are available, including drugs that during exercise, and coronary blood flow does not increase pro-
alter myocardial ion currents and selective cardiac rate inhibitors. portionately. The resulting ischemia with accumulation of acidic
By far, the most common cause of angina is atheromatous metabolites usually leads to pain. In fact, coronary flow reserve
obstruction of the large coronary vessels (coronary artery disease, is frequently impaired in such patients because of endothelial
CAD). Inadequate blood flow in the presence of CAD results in dysfunction, which results in impaired vasodilation. As a result,
effort angina, also known as classic angina. Diagnosis is usually ischemia may even occur at a lower level of myocardial oxygen
made on the basis of the history and stress testing. However, demand. In some individuals, the ischemia is not always accom-
panied by pain, resulting in “silent” or “ambulatory” ischemia. In
* The author thanks Dr. Kanu Chatterjee, MB, FRCP, coauthor of this variant angina, oxygen delivery decreases as a result of reversible
chapter in prior editions. coronary vasospasm, which also causes ischemia and pain.
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