GJ, a 55-year-old male, presents to the ED with substernal chest discomfort (8/0-10) unrelieved by rest. Emergency medical services (EMS) personnel administered nonenteric-coated aspirin and sublingual nitroglycerin (NTG) without relief. GJ reports experiencing three episodes of chest discomfort or pain in the last 24 hours.

Initial assessment findings in the ED include temperature, 37[degrees]C (98.6[degrees]F); heart rate 88, normal sinus rhythm; respirations, 18; SpO2, 95% on room air; BP, 130/70, chest discomfort rated 5/0-10. ECG findings included ST-segment depression in leads V3-4. Initial serum troponin T (TnT), creatine kinase (CK), and CK-myocardial band (CK-MB) levels are all within normal limits.

The patient has a history of type 2 diabetes and hypertension and a family history of heart disease: His father died at age 45 following a myocardial infarction (MI). His current medications include metformin, aspirin, and metoprolol.

GJ is admitted to the chest pain unit to rule out a non-ST-segment elevation myocardial infarction (NSTEMI). Are you prepared to care for this patient according to the latest guidelines?

In 2011, the American College of Cardiology Foundation (ACCF) and the American Heart Association (AHA) Task Force on Practice Guidelines updated the 2007 guidelines for management of patients with unstable angina (UA) and NSTEMI. These clinical practice guidelines provide recommendations that are supported by the best-available evidence and expert opinion. This article reviews the current guidelines and discusses how to apply them to patient care.

Understanding UA/NSTEMI

Although UA and NSTEMI are closely related with similar treatments, they have slightly different characteristics. Both are characterized by chest pain or anginal equivalent (an anginal symptom other than chest pain, such as dyspnea or extreme fatigue), and ST-segment depression or prominent T-wave inversion on ECG; in UA, however, changes are usually transient if present at all. NSTEMI is differentiated by the presence of positive biomarkers of necrosis, such as troponin in the absence of ST-segment elevation.

UA reflects an imbalance between oxygen supply and demand. The guidelines describe three principal presentations of UA:

* angina occurring at rest

* new onset (less than 2 months) of severe angina pain

* angina increasing in frequency, duration, or intensity.

In contrast, pain associated with NSTEMI is usually prolonged and more intense than rest angina or anginal equivalent. It's also caused by an imbalance between oxygen supply and demand; however, in NSTEMI the ischemia is severe enough to cause myocardial damage that is detectable via elevated serum cardiac biomarker levels. The patient may have non-specific ST-segment and T-wave changes on 12-lead ECG. If unrecognized, NSTEMI may lead to ST-segment elevation myocardial infarction (STEMI). In STEMI, the imbalance between oxygen supply and demand is severe enough to cause tissue necrosis, and the patient requires emergency revascularization.

Figure. ECG waveform review

Antiplatelet/anticoagulant therapy

Thienopyridines, a class of drugs that prevent platelet aggregation, are an important component of treatment for UA/NSTEMI. The previous guidelines recommended clopidogrel for antiplatelet therapy. At the time, clopidogrel was the only FDA-approved thienopyridine available. Since then, another thienopyridine, prasugrel, has been approved.

Clopidogrel is also a prodrug but requires several passes through the liver to convert to its active metabolite. It should be administered prior to PCI because onset of action occurs in about 6 hours.

After publication of the guidelines, a third option, ticagrelor, was approved for dual antiplatelet therapy. Although not currently part of the guidelines, this medication is being used in practice. (See Ticagrelor: A new treatment option.)

The patient must continue dual therapy with aspirin and the prescribed thienopyridine upon discharge for the recommended period. If the patient abruptly discontinues the medication, he or she is at high risk for restenosis and STEMI.

Unfortunately, many patients stop the thienopyridine due to its high cost, so assess the patient's ability to pay for the medication. If the patient can't afford it, a social worker or case manager should be contacted for assistance.

Because of the bleeding risk associated with antiplatelet/anticoagulant therapies, educate patients about signs and symptoms to watch for and report. (See Teach patients about bleeding risks.)

GJ receives I.V. NTG, which relieves his chest discomfort; his pain intensity rating is now 0/0-10. Home medications of aspirin and metoprolol are continued and a HMG-CoA reductase inhibitor (statin) is added. Metformin is held in anticipation of the possible need for cardiac catheterization. His blood glucose levels are to be checked before meals and at bedtime with correction insulin.

Serum cardiac biomarkers are checked every 6 hours. The second set reveals an elevated TnT of 0.6 ng/mL (normal, less than 0.2 ng/mL); CK, 400 ng/mL (normal, 0 to 120 ng/mL); and CK-MB, 10 ng/mL (normal, 0 to 3 ng/mL). Due to the patient's ECG abnormalities and longstanding history of diabetes and hypertension, the cardiologist suspects that GJ has significant coronary artery disease and defers prescribing a thienopyridine in case the patient needs CABG surgery. (See Coronary arteries: A closer look.)

Adding glycoprotein IIb/IIIa platelet inhibitors

In addition to aspirin, a continuous infusion of eptifibatide is prescribed for GJ. His platelet count will be checked in 4 hours. The nurse places GJ on bleeding precautions and teaches him signs and symptoms of bleeding. The nurse encourages GJ's wife to bring in an electric razor because shaving with a straight razor may cause bleeding.

Proton pump inhibitor use

Over the past several years, multiple studies have looked at the interaction between clopidogrel and proton pump inhibitors (PPIs) such as omeprazole, lansoprazole, pantoprazole, rabeprazole, and esomeprazole. Providers prescribe PPIs to help reduce the gastrointestinal adverse reactions of dual antiplatelet therapy, such as ulceration and related bleeding, and to allow therapy to continue for the recommended 12-month period.

When caring for a patient who will undergo PCI, notify the healthcare provider if creatinine is more than 1.5 mg/dL (normal, 0.6 to 1.2 mg/dL for males; 0.4 to 1.0 mg/dL for females) or estimated glomerular filtration rate (GFR) is less than 60 mL/minute to discuss an appropriate hydration protocol for the patient preprocedure. Intraprocedure, the cath lab nurse needs to be aware of the amount of contrast used and communicate that volume to the cardiologist. The goal is to limit the total dose.

Acetylcysteine is commonly used off-label to help prevent CIN. However, the mechanism of action isn't well understood and studies on its use as a nephroprotective agent are mixed. The guidelines make no recommendations for or against the use of acetylcysteine for CIN.

The basic metabolic profile shows that GJ's creatinine is 1.7 mg/dL. In anticipation of coronary angiography and PCI in the next 6 to 12 hours, the nurse administers oral acetylcysteine and initiates an I.V. infusion of 0.9% sodium chloride at 150 mL/hour, as prescribed. The nurse provides preprocedure patient education, including the rationale for the medication.

Intensive glucose control

Until further studies are available, the recommendation from the 2004 and 2007 guidelines have been deleted and healthcare providers are referred to the ADA guidelines. In addition, a recommendation to maintain blood glucose levels at less than 180 mg/dL with the goal of avoiding hypoglycemia has been added.

Closely monitor any patient with UA/NSTEMI for both hypo- and hyperglycemia. The patient should be able to demonstrate competency with blood glucose testing and insulin administration (if indicated), preferably by return demonstration. Review signs and symptoms of hypo- and hyperglycemia and treatment with the patient and make sure the patient can verbalize understanding.

Metformin is held in anticipation of coronary angiography. Patients receiving contrast media are at risk for CIN. If a patient receiving metformin develops CIN, the patient is at increased risk for development of lactic acidosis, so the recommendation is to hold metformin before the procedure and for 48 hours postprocedure. It may be safely resumed when normal renal function is confirmed.

GJ's blood glucose is 300 mg/dL and the nurse administers insulin as prescribed. The patient and his wife are concerned that he may need to go home on insulin. The nurse explains the rationale for holding the metformin and reviews signs and symptoms of hypo- and hyperglycemia and treatment with GJ and his wife.

GJ proceeds to the cardiac catheterization suite, where access is gained via the right femoral artery. Findings include nonobstructive stenoses of the right coronary and circumflex artery, and 95% stenosis of the left anterior descending (LAD). A DES is placed in the LAD. Because GJ's serum creatinine was elevated preprocedure, the cath lab nurse communicates with the cardiologist regarding the amount of contrast administered throughout the procedure and ensures that I.V. hydration continues. Prasugrel is administered at the end of the procedure.

When the patient returns to the progressive care unit, the nurse provides postprocedure care, including assessment of vital signs, pain intensity rating, neurovascular function, and access site every 15 minutes for 1 hour, every 30 minutes x2, then hourly x4. The nurse also documents accurate intake and output. A repeat ECG shows resolution of ischemic changes and no pathologic Q waves, which would indicate an MI.

Many recommendations are unchanged

The next day, GJ's access site and serum creatinine are stable. He walks around the cardiac unit and doesn't experience any cardiac dysrhythmias. His 2-D echo reveals an ejection fraction of 50% (normal, 60% to 75%). At discharge, GJ is continued on aspirin, clopidogrel, a beta-blocker, and a statin, and is instructed to restart metformin on day 3 post-PCI.

The nurse educates GJ and his wife about the importance of continuing dual platelet therapy as prescribed. GJ can verbalize the signs and symptoms of bleeding. Fortunately, the patient has a prescription plan and prasugrel is on formulary.

Keeping current

As the landscape of cardiovascular disease management changes, nurses must be able to quickly review new standards and guidelines and adapt them to practice. Educating patients with UA/NSTEMI about their condition and prescribed treatment will help them manage their condition after discharge and recognize signs and symptoms requiring immediate intervention in the future.

Ticagrelor: A new treatment option

Released in 2011, ticagrelor is a P2Y12 platelet inhibitor used in UA/NSTEMI patients to prevent thrombosis. It's used in combination with low-dose aspirin-use of full-strength aspirin with ticagrelor has been shown to decrease ticagrelor's efficacy. Major adverse reactions include bleeding and dyspnea, which is usually self-limited. If a patient is expected to undergo CABG surgery, hold ticagrelor for at least 5 days preprocedure.

Teach patients about bleeding risks

Before a patient is discharged on antiplatelet/anticoagulant therapy, review signs and symptoms of bleeding; for example, nosebleeds, black tarry stools, easy bruising or purple spots on the skin, blood in the urine, coughing up or vomiting blood or material resembling coffee grounds, and feeling weak or dizzy. The patient should immediately contact the healthcare provider or call 911 if bleeding develops. The healthcare provider will weigh the risk of bleeding versus the benefit of the medication to determine if the dosage should be adjusted or the medication discontinued.

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