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CASE 12-3, QUESTION 2: E.R also buys a bottle of over-the-counter ibuprofen. On further questioning, you

learn that E.R. suffers from occasional back and knee pain and uses ibuprofen three to five times a week for

pain relief. How should E.R. be educated regarding the use of ibuprofen and aspirin concomitantly?

In 2006, the FDA released a warning statement on the concomitant use of both

aspirin and ibuprofen. The impetus for the statement was the growing recognition that

nonsteroidal antiinflammatory drugs (NSAIDs), in particular ibuprofen, may attenuate

the antiplatelet effects of low-dose aspirin. This FDA warning was then followed by

an updated scientific statement, from the AHA.

92 The mechanism of this interaction is

that both aspirin and nonselective NSAIDs bind to the same acetylation sites of the

cyclooxygenase enzyme. Although aspirin does this in a nonreversible fashion,

binding by an NSAID occurs in a reversible fashion. If an NSAID, such as ibuprofen,

is present, aspirin will be unable to bind to its site of action, and will be rapidly

cleared from the plasma. The result is the patient will not receive the antiplatelet

benefit of aspirin.

E.R. should be counseled on the consequences of the interaction between her

aspirin and ibuprofen. Additionally, if she can avoid or at least minimize (both dose

and duration) the use of ibuprofen, the effect on her cardiovascular health would be

optimized. If occasional use of ibuprofen cannot be avoided, it should be

administered to minimize the potential for interacting with her aspirin. This would

include taking ibuprofen at least 2 hours after her daily dose of aspirin, as well as

taking her daily aspirin dose at least 8 hours after the last dose of ibuprofen.

Although similar concerns exist for other nonselective NSAIDs (naproxen,

diclofenac), no formal recommendations exist on how to manage concomitant use of

these agents with aspirin.

92 Beyond the potential drug–drug interaction with aspirin

therapy, there has emerged a large body of observational evidence that the use of

NSAIDs in patients with underlying CVD may increase the risk of major adverse

cardiovascular events. Although the underlying mechanisms remain to be determined,

clinicians should minimize the use of NSAIDs if possible in patients with underlying

CVD.

93

REVASCULARIZATION

Percutaneous Coronary Intervention

CASE 12-3, QUESTION 3: Nine months later, E.R. returns to her cardiologist stating that her chronic angina

has been worsening. She is experiencing chest pain more frequently and much sooner when she does any type

of physical activity. Her current medications are the same as discussed previously and it is felt that her medical

management has been optimized as much as possible. After discussions with her cardiologist, she elects to

undergo revascularization with PCI for symptom relief. What is the current standard for prevention of acute

complications during PCI?

PCI, also known as angioplasty, involves the percutaneous insertion of a balloon

catheter into the femoral or brachial artery. The catheter is advanced up the aorta and

into the coronary arteries at the coronary sinus. PCI initially involved the inflation of

a catheter-borne balloon that mechanically dilated a coronary artery obstruction

through arterial intimal disruption, plaque fissuring, and stretching of the arterial

wall. Balloon inflations were repeated until the plaque was compressed and

coronary blood flow resumed. Since then, alternative devices have been developed,

including rotational blades designed to remove atheromatous material, lasers to

ablate plaques, and intracoronary stents that are designed to maintain the patency of

the vessel after it is reopened.

94 Stents can be of the bare-metal (BMS) variety, or

contain a drug impregnated on the surface of the stent to prevent restenosis (DES). It

is estimated that more than 1,265,000 PCI procedures are performed in the United

States each year. An overwhelming majority of these procedures involve placement

of a BMS or DES (Fig. 12-5). PCI is indicated in patients with single-vessel or

multi-vessel disease and who are either symptomatic or asymptomatic.

20,94,95

Because of mechanical disruption of the atherosclerotic plaques and exposure of

plaque contents to the bloodstream during PCI, potent antiplatelet and antithrombotic

strategies are needed to prevent acute thrombotic events such as MI and death.

Current strategies in patients undergoing elective PCI involve the administration of

aspirin, a P2Y12 antagonist (clopidogrel, prasugrel, or ticagrelor), an antithrombin

agent, and occasionally a glycoprotein (GP) IIb/IIIa receptor antagonist in selected

patients. Although ticagrelor and prasugrel represent alternatives to clopidogrel in

patients undergoing PCI, current ACC/AHA guidelines recommend their use only in

patients undergoing PCI in the setting of ACS. In patients not taking aspirin on a daily

basis, 300 to 325 mg of aspirin should be given at least 2 hours before the procedure.

Patients currently on daily aspirin therapy should receive 75 to 325 mg of aspirin

before PCI is performed. A 600-mg loading dose of clopidogrel on or before the time

of the procedure is currently recommended, producing an antiplatelet action within 2

hours.

16,17,20,95 Adequate antithrombin therapy such as unfractionated heparin, the lowmolecular-weight heparin enoxaparin, or the direct thrombin inhibitor bivalirudin

should be used in patients having elective PCI.

20,95

(See Chapter 13, Acute Coronary

Syndrome, for more information.)

Figure 12-5 Vascular stent. A: A balloon catheter positions the stent at the site of arterialstenosis. B: Inflation of

the balloon dilates the artery and expands the stent. C: The balloon is collapsed and withdrawn, leaving the

expanded stent in position. (Illustration by Neil O. Hardy, Westpoint, CT.)

p. 225

p. 226

CASE 12-3, QUESTION 4: E.R. undergoes PCI plus placement of a DES to address a 75% lesion in her

proximal left circumflex artery. What advantages and disadvantages are there in the decision to place a DES

versus a BMS?

The overall success of any procedure is directly related to the experience of the

operator, patient factors (such as LV function or number of vessels treated), and the

equipment used. In patients receiving balloon angioplasty alone (without stent

placement), repeat revascularization procedures (either repeat angioplasty or

surgery) may be required in as many as 32% to 40% of cases because of lesion

recurrence at the angioplasty site. The process is known as restenosis.

94 Many

pharmacologic strategies have been studied in an attempt to reduce the risk of

restenosis. The outcome with most methods has been disappointing. The only strategy

that has been associated with a decrease in restenosis is the use of intraluminal

stents.

94 Stents are essentially metal scaffolding devices placed into the vessel after

balloon inflation has taken place. They provide a physical barrier to the recurrence

of a significant stenosis at the site. One of the early drawbacks of the use of stents

was the need for complicated antithrombotic regimens, including aspirin, heparin,

dipyridamole, and warfarin, to prevent in-stent thrombosis. DAPT—a combination of

a P2Y12 antagonist and aspirin—is effective at reducing in-stent thrombosis and is

now recommended for use after stent placement.

20,95 The duration of DAPT will

depend on the type of stent used, as well as other clinical characteristics of the

patient.

Recently, stents that elude antiproliferative agents such as sirolimus, paclitaxel,

zotarlimus, or everolimus have been shown in clinical trials to reduce the incidence

of restenosis compared with BMS.

96 Restenosis rates in clinical trials with these

DES were in the single-digit range, as compared to 15% to 20% with traditional

BMS. Soon after their introduction to the US market, DES use grew to the point that

greater than 90% of stent use was DES. This trend abruptly halted in the fall of 2006

when several reports indicated a higher than expected incidence of stent thrombosis a

year or more after DES placement. Although late stent thrombosis had previously

been reported with BMS usage, the incidence was rare.

20 Shortly after these initial

reports, an explosion of scientific literature emerged on the topic. Delayed

endothelialization is seen with DES compared with BMS. After placement of an

intracoronary stent, a healing process typically occurs resulting in growth of a

protective layer of endothelial cells over the stent surface, removing the stent surface

from blood exposure and drastically reducing the stimulus for thrombosis. In the case

of DES coated with paclitaxel, sirolimus, or everolimus, cellular growth may be

inhibited, significantly impairing endothelialization of the stent surface. In a small

number of patients, endothelialization does not seem to occur at all. In this scenario,

the stent structure remains continually exposed to flowing blood and is a potent

stimulus for thrombosis.

97 Because of the concerns of late stent thrombosis, the usage

of DES has decreased. Some use of DES is likely to continue, however, owing to the

tangible benefits in reduction of revascularization procedures in some patients.

Therefore, practitioners will need to continue to stay abreast of evolving information

regarding appropriate strategies to prevent late stent thrombosis.

One critical issue that has been identified as a cause of late stent thrombosis with

DES is the premature discontinuation of DAPT. As such, consideration of whether

the patient is likely to comply with aspirin and P2Y12 antagonist therapy, or afford

such therapy based on insurance status, has become a significant factor in the

decision process between using a BMS or DES. Previous recommendations called

for varying durations of combined therapy, depending on the type of stent used.

Because of the recognition of a delayed healing response to DES, current guidelines

recommend at least 1 year of DAPT in patients receiving a DES if patients are not at

an elevated risk of bleeding. For BMS placement, DAPT should continue for a

minimum of 1 month, and up to 1 year ideally, but this extended duration is not as

critical as it is in the setting of DES placement. After PCI, it is reasonable to use

aspirin 81 mg daily rather than higher doses.

20 The dose of clopidogrel should be 75

mg/day.

20,95

CASE 12-3, QUESTION 5: Would revascularization therapy with coronary artery bypass grafting have been

a better option for E.R. than PCI and stent placement?

Coronary artery bypass grafting is a complicated surgical procedure during which

an atherosclerotic vessel is bypassed using either a patient’s saphenous vein or

internal mammary artery (IMA; Fig. 12-6). The graft (i.e., the saphenous vein or

IMA) then allows blood to flow past the obstruction in the native vessel. The goals

of antianginal therapy, whether medical (pharmacologic) or revascularization, remain

unchanged: (a) to prolong life, (b) to prevent MI, and (c) to improve the quality of

life.

The outcomes of medical therapy, PCI, and revascularization with CABG have

been compared, and current guidelines are available.

1,21 When compared with

medical treatment in patients who would not be considered high risk, PCI in general

offers no improvement in the long-term incidence of MI or cardiovascular death, but

significantly reduces symptoms.

1 Because of her escalating symptoms on triple drug

therapy, the choice of PCI for E.R. is justified.

Figure 12-6 Coronary artery bypass graft (CABG). A: A segment of the saphenous vein carries blood from the

aorta to a part of the right coronary artery that is distal to an occlusion. B: The mammary artery is used to bypass

an obstruction in the left anterior descending (LAD) coronary artery. (Reprinted with permission from Cohen BJ.

Medical Terminology. 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2003.)

p. 226

p. 227

Certain high-risk patient subgroups clearly have an improved outcome with

CABG. These include (a) patients with significant left main coronary disease; (b)

patients who have three-vessel disease, especially with LV dysfunction; (c) patients

with two-vessel disease with a significant proximal LAD lesion; (d) patients who

have survived sudden cardiac death; and (e) patients who are refractory to medical

treatment. In patients who do not meet these criteria, either medical treatment or PCI

is a viable option.

1,20 Because E.R. does not fall into one of these categories, PCI is

preferable owing to the less invasive nature of the procedure and the equivalent

outcomes that are seen. These results were recently confirmed in the Clinical

Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE)

trial.

43 Patients with CAD were randomly assigned to aggressive medical treatment

with optimization of medical therapy and risk factors, or aggressive medical

treatment plus PCI. During a 4.6-year period, no significant difference was noted

between the groups in cardiovascular outcomes (death, MI, stroke, hospitalization for

ACS). The only difference noted was better control of anginal symptoms early on

with PCI, but that difference was no longer significant at the end of the study. These

results highlight the crucial role of optimizing medical therapy (including diet,

lifestyle changes, risk factor modification) for patients with CAD, regardless of

whether revascularization is performed.

1

CASE 12-3, QUESTION 6: E.R. undergoes PCI plus stent placement and returns to your pharmacy to have

a new prescription filled. The prescription calls for clopidogrel at a dose of 150 mg once a day for 1 week, then

75 mg a day thereafter with 11 monthly refills. You have not seen clopidogrel dosed in such manner and are

wondering what the rationale for the higher dose is, and whether there is evidence to support its use.

Clopidogrel, a thienopyridine, inhibits platelet function as a noncompetitive

antagonist of the P2Y12 platelet adenosine diphosphate receptor. Clopidogrel is

dosed at 75 mg daily, and this dose has been demonstrated to be effective and safe as

monotherapy, or as a component of DAPT with aspirin, in a wide variety of settings

for patients with CAD.

98 Despite proven efficacy, patients continue to experience

clinical events while receiving clopidogrel.

99

It is now understood that clopidogrel

does not produce a consistent antiplatelet response in many patients.

100

Although the term clopidogrel resistance was first used to describe patients who

do not have the expected antiplatelet response to standard doses of clopidogrel, a

better term to describe this phenomenon is clopidogrel nonresponsiveness.

Alternatively, the phrase high on-treatment platelet reactivity is also used commonly

in the literature, especially when characterizing the clinical consequences of

decreased antiplatelet response.

100 The presence of high on-treatment platelet

reactivity in patients who have undergone PCI has been linked to a higher rate of

stent thrombosis, MI, repeat revascularization, and death. This link has been

observed in both stable CAD patients undergoing elective PCI, and patients with

ACS. Although nonresponsiveness identifies an elevated risk for ischemic events, not

all patients with identified clopidogrel nonresponsiveness necessarily go on to have

recurrent events.

99

There is a lack of consistency of how clopidogrel nonresponsiveness is defined. It

may be defined as the presence of a recurrent ischemic event while on therapy. But,

thrombosis is a complex interplay of many different factors and recurrent clinical

events do not necessarily imply a lack of antiplatelet effect. The identification of a

lack of the expected biologic effect on platelet function is a more appropriate

definition to work with. However, there are multiple tests available to assess the

antiplatelet activity of clopidogrel (and other antiplatelet agents), and it is unclear

which assay correlates best with clinical outcome and would be preferred to assess

clopidogrel nonresponsiveness. Because of the variability in available platelet

function tests, as well as definitions of nonresponsiveness, estimates for the

incidence of clopidogrel nonresponsiveness range anywhere from 5% to 44%.

100

Table 12-8 lists some of the available laboratory testing modalities for antiplatelet

agents, their pros and cons, as well as previously identified levels of high ontreatment platelet reactivity.

101

Potential reasons for clopidogrel nonresponsiveness are multifactorial. One source

of nonresponsiveness is in the decreased biotransformation of clopidogrel from its

prodrug form to its active metabolite. Biotransformation is a multistep process

through the cytochrome P-450 system, but the most important enzyme is CYP2C19,

which exhibits variable metabolic capacity. Patients with the *1/*1 CYP2C19 alleles

are considered extensive metabolizers and are capable of generating sufficient levels

of clopidogrel’s active metabolite. Patients with one or two copies of either the *2 or

*3 alleles (considered loss of function alleles) are considered either intermediate or

poor metabolizers, generate lower amounts of active metabolite, and generally

produce a reduced antiplatelet effect as measured with available platelet function

testing.

102 Conversely, patients with one or two copies of the *17 allele (considered a

gain of function allele) are considered ultrarapid metabolizers and demonstrate a

heightened antiplatelet response with clopidogrel. With the unraveling of

pharmacogenomic factors related to clopidogrel response, a great deal of attention

has been given to the idea of identifying patients with copies of either the *2 or *3

allele and adjusting antiplatelet therapy accordingly. The FDA added language to the

clopidogrel package insert specifying that poor metabolizers have a higher

cardiovascular event rate, and that tests are available to identify who those patients

are who carry these genes.

103 Although the presence of either loss of function allele

has been associated with an increased risk of clinical outcomes in some trials, this

finding has not been uniformly observed. Additionally, there are no prospective trials

evaluating a strategy of genetic testing with subsequent therapy changes. As such,

genetic testing related to clopidogrel therapy is considered to be in the

investigational stage.

Table 12-8

Commonly Used Platelet Function Tests for Assessment of Antiplatelet

Effects

121,122

Test Pros Cons Monitoring Key Points

Turbidimetric

aggregometry, commonly

referred to as light

transmission aggregometry

or LTA

Historical gold standard Large blood volume

Expensive

Poor reproducibility

Time-consuming

Technical complexity

Whole blood assay

Can be used for multiple

antiplatelet agents with

variable reagents

VASP phosphorylation Whole blood assay

Small blood volume

needed

Technical complexity

Expensive

Requires a flow cytometer

Specific for

thienopyridines

Cutoff for antiplatelet

nonresponsiveness

PRI > 50%

VerifyNow True point-of-care assay

Large number patients

studied

Whole blood assay

Simple and rapid

Cartridge cost

Limited ranges for

hematocrit and platelet

count

Can assess multiple

antiplatelet agents

Cutoff for antiplatelet

nonresponsiveness

PRU >235–240

Thromboelastography Whole blood assay

Point of care

Limited clinicalstudies

Substantial pipetting of

reagents

Can assess multiple

antiplatelet agents

PRI, platelet reactivity index; PRU, platelet reaction units; VASP, vasodilator-stimulated phosphoprotein.

p. 227

p. 228

An alternative approach to address the issue of clopidogrel nonresponsiveness is

to assess platelet function in patients receiving clopidogrel. To date, trials conducted

have indicated that increasing loading or maintenance doses of clopidogrel do have

the potential to convert patients deemed nonresponders to responders.

104 However,

not all patients can be converted and no trial has demonstrated that such an approach

leads to improved clinical outcomes.

105 Additionally, data indicate no improvements

in clinical outcomes from platelet function monitoring.

106

Empirically using higher doses of clopidogrel in all patients undergoing PCI is an

additional approach that has been considered in addressing clopidogrel

nonresponsiveness. Although no trials have been conducted in the elective PCI

setting, the CURRENT-OASIS 7 trial randomly assigned more than 25,000 ACS

patients to either standard dosing of clopidogrel (300 mg load, then 75 mg daily) or a

higher dosing regimen (600 mg load, then 150 mg daily for 7 days, then 75 mg

daily).

107 Patients were also randomly assigned to either high-dose (300–325 mg

daily) or low-dose (75–100 mg daily) aspirin. Approximately 17,000 of the 25,000

patients underwent PCI. Results showed that in PCI patients, the higher dosing

regimen of clopidogrel reduced the risk of MI at the cost of a higher incidence of

major bleeding.

Although the results of the CURRENT-OASIS 7 trial might be viewed in a

positive light in relation to the prescription E.R. is presenting with today in your

pharmacy, an important caveat is that the CURRENT-OASIS 7 trial was conducted in

ACS patients, and it is unclear if the same benefits (and risks) can be expected in

patients undergoing elective PCI for symptom management of chronic stable angina.

CASE 12-3, QUESTION 7: While you are filling her new clopidogrel prescription, E.R. mentions that she has

been having some problems with heartburn lately and asks where she can find some over-the-counter

omeprazole. Is omeprazole appropriate to use in a patient with clopidogrel therapy?

Another source of variable clopidogrel response is through potential drug–drug

interactions involving the CYP2C19 enzyme. One class of agents that has generated

substantial controversy in this area are the proton-pump inhibitors (PPIs), given the

likelihood of coadministration to prevent GI bleeding as a result of antiplatelet

therapy. Several studies indicate there is a pharmacokinetic interaction between

PPIs, in particular omeprazole, with clopidogrel resulting in reduced levels of the

active metabolite. Evidence that this interaction is clinically significant is variable.

Several retrospective analyses suggest an increased risk for CVD events in patients

taking PPIs with clopidogrel therapy.

108–112 However, the available evidence from

randomized controlled trials does not support an increased clinical risk with this

combination.

112–114 However, one study has identified that PPI use alone is associated

with an elevated risk of CVD events.

115 Clinicians are faced with addressing this

issue from a medical–legal aspect as the FDA has incorporated language into the

clopidogrel package insert warning against the concomitant administration of

omeprazole and esomeprazole with clopidogrel.

116 The recommendation applies to

omeprazole and esomeprazole but not other PPIs. There is some evidence to suggest

that alternative PPIs such as pantoprazole have a lower propensity to inhibit

CYP2C19 and interact with clopidogrel. Until further information becomes

available, clinicians should first validate the need for PPI therapy in clopidogrel

patients. If acid suppressive therapy is needed, the use of a H2 antagonist (excluding

cimetidine which can inhibit CYP enzymes) or a PPI less likely to interact with

clopidogrel would seem to be appropriate options to consider.

117

VARIANT ANGINA (CORONARY ARTERY

SPASM)

Clinical Presentation

CASE 12-4

QUESTION 1: A.P., a 35-year-old woman, is hospitalized for evaluation of severe chest pain, which occurs

almost daily at about 5 AM. A.P. ranks the severity of pain as 7 to 8 on a scale of 1 to 10. It is associated with

diaphoresis and is not relieved by change in position. A.P. has no cardiovascular risk factors, and her hobbies

include triathlon competition and rock climbing, neither of which has caused chest pain. She follows a strict

vegetarian diet and takes no medications. Admission ECG reveals sinus bradycardia at 56 beats/minute. Serum

electrolytes, chemistry panel, and cardiac enzymes are all within normal limits.

On day 1 of hospitalization, A.P. is awakened at 6 AM abruptly by severe chest pain. Her vital signs at this

time include the following: heart rate, 55 beats/minute; supine BP, 110/64 mm Hg; and respiratory rate, 12

breaths/minute. An ECG shows sinus bradycardia with marked ST-segment elevation. The pain is relieved

within 60 seconds by one NTG 0.4-mg sublingual tablet. During the day, she completes an exercise tolerance

test without complication or evidence of CAD.

On the second day, A.P. undergoes cardiac catheterization, and no coronary atherosclerosis is visualized.

A.P. is diagnosed as having Prinzmetal variant angina. Discharge medications include oral amlodipine 10 mg

every day at 11 PM and NTG lingualspray 0.4 mg as needed for chest pain.

Is A.P.’s presentation typical for Prinzmetal variant angina?

A.P. presents with a classic picture of variant (Prinzmetal) angina, with transient

total occlusion of a large epicardial coronary artery as a result of severe segmental

spasm. Clinical manifestations include chest pain occurring at rest, often in the

morning hours. As with A.P., patients with Prinzmetal variant angina generally are

younger than patients with chronic stable angina and do not carry a high-risk profile.

Other vasospastic disorders, such as migraine attacks or Raynaud’s phenomenon,

may be present; smoking and alcohol ingestion can be important contributing

factors.

118

The hallmark of variant angina is ST-segment elevation on the ECG, which

denotes rapid and complete occlusion of the coronary artery. Many patients also have

asymptomatic episodes of ST-segment elevation. Transient arrhythmias and

conduction disturbances may be observed during pain, depending on the severity of

the myocardial ischemia.

118

p. 228

p. 229

As documented by angiography, A.P. has vasospasm of the large RCA. This

transient, reversible narrowing is probably caused by increased coronary vascular

resistance. It can occur in the absence of atherosclerosis, as illustrated by A.P., and

also in the presence of CAD. One possible explanation for vasospasm occurring

more commonly at night or during the early morning hours is increased vasomotor

tone secondary to diurnal variations in catecholamines.

Therapy

CASE 12-4, QUESTION 2: Oral amlodipine 10 mg every day was ordered for A.P. Would long-acting

nitrates or β-adrenergic blockers be reasonable alternatives to amlodipine for A.P.? Is one CCB preferable to

another for treatment of Prinzmetal variant angina?

Because of their antispasmodic effects and low incidence of side effects, CCBs

are generally selected over nitrates or β-blockers for nocturnal vasospastic angina.

All CCBs appear equally effective in preventing Prinzmetal variant angina.

118

Intrinsically long-acting or sustained-release forms are preferred, however, and some

patients may respond better to one agent than to another.

In patients who continue to experience pain using maximal CCB doses,

combination therapy with a nitrate should be tried. Nitrates cause vasodilation by a

different mechanism than CCBs and are effective in treating Prinzmetal variant

angina.

118 To avoid tolerance, the nitrate-free interval for A.P. should be scheduled

during the day so that the early morning hours when vasospasm occurs are covered

by NTG. For example, A.P. could apply a transdermal NTG patch at bedtime and

remove it on awakening. Statin therapy is indicated for A.P.

118

Blockade of the β2

-receptors that mediate vasodilation may allow unopposed α1

-

mediated vasoconstriction with worsening symptoms. Even a cardioselective βblocker could worsen Prinzmetal variant angina.

118 Therefore, a CCB or nitrate is

preferred.

CASE 12-4, QUESTION 3: Will A.P. require treatment for the remainder of her life?

During the first year of therapy, up to 50% of patients experience spontaneous

remission by an unknown mechanism.

118 This occurs most often in patients who have

had a short duration of symptoms or who have normal or mildly diseased coronary

arteries (i.e., isolated vasospasm without atherosclerosis). If A.P. is pain free and

not experiencing significant arrhythmias or silent ischemic episodes of Prinzmetal

angina after 1 year, amlodipine could be tapered and discontinued. It is also

possible, however, that she will require treatment indefinitely. Modification of

smoking and ethanol ingestion may promote remission of Prinzmetal angina.

118

CARDIAC SYNDROME X

CASE 12-5

QUESTION 1: K.G., a 50-year-old female executive, has undergone an extensive cardiovascular workup for

exertional angina associated with a 3-mm ST-segment depression. A recent cardiac catheterization did not

reveal any atherosclerosis. The cardiologists believe K.G. has cardiac syndrome X. What drug therapy might be

indicated for K.G.?

Cardiac syndrome X is a syndrome of angina or angina-like chest pain in the

setting of a normal coronary arteriogram, and ST-segment depression during

exercise. Several theories exist regarding the mechanism of pain production,

including microvascular dysfunction producing ischemia or chest discomfort without

ischemia in patients who may have an abnormal perception of pain. Half of patients

with cardiac syndrome X present with chest pain induced by exercise followed by 15

to 20 minutes of chest discomfort.

119

By symptoms alone, K.G.’s presentation does not significantly differ from that of a

patient with exercise-induced angina secondary to atherosclerosis. Of concern is the

finding of a 3-mm ST-segment depression on K.G.’s ECG, which raises concern of

severe CAD. The negative findings from her cardiac catheterization, however, rule

against both CAD and coronary artery spasm as a cause of her symptoms, and help to

confirm the diagnosis of cardiac syndrome X.

119

Treatment with a nitrate, CCB, or β-blocker all appear to offer some relief, but

overall the response to therapy in these patients is poor. The choice of agent will

likely depend on specific patient characteristics. Sublingual NTG is often ineffective

at treating acute attacks, although it should still be prescribed. Often a combination of

anti-ischemic therapy, analgesic therapy, and lifestyle modifications is necessary.

119

KEY REFERENCES AND WEBSITES

A full list of references for this chapter can be found at

http://thepoint.lww.com/AT11e. Below are the key references and websites for this

chapter, with the corresponding reference number in this chapter found in parentheses

after the reference.

Key References

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inhibitors and thienopyridines: a focused update of the ACCF/ACG/AHA 2008 expert consensus document on

reducing the gastrointestinal risks of antiplatelet therapy and NSAID use: a report of the American College of

Cardiology Foundation Task Force on Expert Consensus Documents. Circulation. 2010;122(24):2619. (117)

Antithrombotic Trialists’ (ATT) Collaboration. Aspirin in the primary and secondary prevention of vascular disease:

collaborative meta-analysis of individual participant data from randomised trials. Lancet. 2009;373:1849. (87)

Chaitman BR. Ranolazine for the treatment of chronic angina and potential use in other cardiovascular conditions.

Circulation. 2006;113:2462. (15)

Fihn SD et al. 2012 ACCF/AHA/ACP/AATS/PCNA/SCAI/STS guideline for the diagnosis and management of

patients with stable ischemic heart disease: a report of the American College of Cardiology

Foundation/American Heart Association Task Force on Practice Guidelines, and the American College of

Physicians, American Association for Thoracic Surgery, Preventative Cardiovascular Nurses Association,

Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons. Circulation.

2012;126:e354–e471. (1)

Fox K et al. Guidelines on the management of stable angina pectoris: executive summary. The task force on the

management of stable angina pectoris of the European Society of Cardiology. Eur Heart J. 2006;27:1341.

Hippisley-Cox J, Coupland C. Effect of combinations of drugs on all cause mortality in patients with ischaemic

heart disease: nested case-control analysis. BMJ. 2005;330:1059. (52)

Kaul S et al. Thiazolidinedione drugs and cardiovascular risks: a science advisory from the American Heart

Association and American College of Cardiology Foundation. J Am Coll Cardiol. 2010;55:1885.

Levine GN et al. 2011 ACCF/AHA/SCAI guideline for percutaneous coronary intervention: a report of the

American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines

and the Society for Cardiovascular Angiography and Interventions. J Am Coll Cardiol. 2011;58:e44–e122. (95)

p. 229

p. 230

Mehta SR et al. Double-dose versus standard-dose clopidogrel and high-dose versus low-dose aspirin in individuals

undergoing percutaneous coronary intervention for acute coronary syndromes (CURRENT-OASIS 7): a

randomised factorial trial. Lancet. 2010;376(9748):1233. (107)

Parikh P et al. Diets and cardiovascular disease: an evidence-based assessment. J Am Coll Cardiol. 2005;45:1379.

(48)

Pepine CJ, Wolff AA. A controlled trial with a novel anti-ischemic agent, ranolazine, in chronic stable angina

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Windecker S et al. 2014 ESC/EACTS Guidelines on myocardial revascularization: the Task Force on Myocardial

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Percutaneous Cardiovascular Interventions (EAPCI), Eur Heart J. 2014;35(37):2541–2619. (20)

Yusuf S et al. Effect of potentially modifiable risk factors associated with myocardial infarction in 52 countries (the

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Key Websites

American College of Cardiology. CardioSource, http://www.cardiosource.org/acc.

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US Food and Drug Administration. Information for Healthcare Professionals: Update to the labeling of Clopidogrel

Bisulfate (marketed as Plavix) to alert healthcare professionals about a drug interaction with omeprazole

(marketed as Prilosec and Prilosec OTC),

http://www.fda.gov/safety/medwatch/safetyinformation/ucm225843.htm.

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