59-year-old male with crushing chest pain

Case study

A 59-year-old man has been admitted. He has a 90-minute history of severe crushing chest pain. His ECG shows 3mm ST segment elevation in leads V₁ to V₄ consistent with an acute anterior myocardial infarction.

He is given loading doses of aspirin and clopidogrel. Forty-five minutes after admission, he undergoes successful primary percutaneous coronary intervention (PCI) with the insertion of a drug eluting stent into his critically narrowed left anterior descending coronary artery. By the time he is returned to the coronary care unit 30 minutes after the procedure, he is pain free and there is partial resolution of his ECG changes.

His U + Es, full blood count, blood glucose, renal, hepatic and thyroid function are all normal.

Fasting lipid profile: cholesterol = 6.8mmol/litre; HDL cholesterol = 1.2mmol/litre; LDL cholesterol = 4mmol/litre; triglycerides = 3.5mmol/litre 

Although he has a history of asthma, it is well controlled and he has never been hospitalised for it. He uses his salbutamol inhaler rarely. He also has a history of gastro-oesophageal reflux with endoscopically confirmed oesophagitis two years ago.

He smokes 20 cigarettes per day and consumes approximately 35 units of alcohol per week. His body mass index = 26kg/m² 

His father died of a myocardial infarction at 62 years of age, but there is no other adverse family history.

An intravenous infusion of abciximab is to continue for 12 hours. He will also undergo a risk assessment for venous thromboembolism. 

Six hours after the PCI, he becomes breathless and a chest x-ray reveals pulmonary oedema. Echocardiography shows hypokinesis of the interventricular septum and apex with a left ventricular ejection fraction of 32%. He is given furosemide 40mg by slow intravenous injection.

Curently, blood pressure = 115/85mmHg, heart rate = 95 beats/minute.

When can lisinopril be started in this patient?

The prescribing notes on Management of ST-segment Elevation Myocardial Infarction (section 2.10.1, BNF 60) advise that in the absence of contra-indications and hypotension, an ACE inhibitor can be started within 24 hours of the myocardial infarction and continued for at least five to six weeks. Longer-term treatment with an ACE inhibitor will be particularly beneficial in this patient with evidence of left ventricular dysfunction. According to the lisinopril monograph in BNF 60, it should be initiated at 2.5mg once daily when the systolic blood pressure is 100-120mmHg. A relatively high dose of ACE inhibitor is required to produce prognostic benefit, so if tolerated, the dose of lisinopril should be increased to 5mg once daily and then increased in steps no greater than 10mg at intervals of at least two weeks up to max. 35mg daily. Blood pressure, renal function, and electrolytes should be monitored during treatment.         

Should this patient receive eplerenone?

According to the eplerenone monograph in BNF 60, it can be used within 3-14 days of the myocardial infarction in this patient with left ventricular dysfunction and evidence of heart failure. Appendix 1, BNF 60, warns of an increased risk of severe hyperkalaemia when eplerenone is given with an ACE inhibitor. The plasma-potassium concentration should be monitored during treatment and when the dose is changed. The patient should be advised to take a low-potassium diet.

After starting lisinopril and eplerenone, the patient is stable and no longer complaining of breathlessness. Should he also receive a beta-blocker or a calcium-channel blocker?

Following a ST-segment elevation myocardial infarction, early administration of beta-blockers is beneficial and should be given to patients without contra-indications. Bisoprolol and carvedilol can reduce mortality in any grade of stable heart failure.

According to the prescribing notes on Beta-adrenoceptor Blocking Drugs (section 2.4, BNF 60), beta-blockers can precipitate bronchospasm and should, therefore, usually be avoided in patients with a history of asthma. When there is no suitable alternative, it may be necessary for a patient with well controlled asthma to receive treatment with a beta-blocker for a co-existing condition (e.g. heart failure or following myocardial infarction); in this situation, a cardioselective beta-blocker should be selected and initiated at a low dose by a specialist; the patient should be monitored closely for adverse effects.  

The prescribing notes on Management of ST-segment Elevation Myocardial Infarction (section 2.10.1, BNF 60) advise that diltiazem or verapamil can be considered if a beta-blocker cannot be used; however, both drugs are contra-indicated in this patient with left ventricular dysfunction. Other calcium channel blockers have no place in routine long-term management after a myocardial infarction.

In this patient with stable heart failure and well controlled mild asthma, the cardioselective beta-blocker, bisoprolol, should be started by a specialist. 

How should bisoprolol be initiated in this patient?

According to the prescribing notes on Heart Failure (section 2.5.5, BNF 60), bisoprolol should be started at a very low dose and titrated very slowly over a period of weeks or months. Symptoms may deteriorate initially, calling for adjustment of concomitant therapy. His heart rate, blood pressure, respiratory function and clinical status should be monitored frequently during treatment and after each dose titration (full details of the dose regimen can be found in the drug monograph). In particular, he should be asked to report use of the salbutamol inhaler more than twice a week, or symptoms such as increasing  breathlessness, cough, or tight chest.  

How long should aspirin and clopidogrel be continued?

According to the prescribing notes on Antiplatelet Drugs (section 2.9, BNF 60), low-dose aspirin should be continued indefinitely after percutaneous coronary intervention involving the placement of a coronary stent. Clopidogrel is recommended for 12 months following the placement of a drug eluting stent. Clopidogrel should not be discontinued prematurely because there is an increased risk of stent thrombosis as a result of the eluted drug slowing the re-endothelialisation process. Patients considered to be at high risk of developing late stent thrombosis with a drug eluting stent may require a longer duration of treatment with clopidogrel - in some cases life-long therapy. 

Is it appropriate for the patient to take omeprazole?   

The patient is taking a maintenance dose of omeprazole for gastro-oesophageal reflux disease. According to Appendix 1, BNF 60, the antiplatelet effect of clopidogrel is reduced by omeprazole and this is classified as a serious drug interaction. A similar drug interaction also occurs between esomeprazole and clopidogrel. The antiplatelet effect of clopidogrel may possibly be reduced by lansoprazole, pantoprazole, and rabeprazole. If it is essential to continue a proton pump inhibitor, lansoprazole, pantoprazole, or rabeprazole should be used in preference to omeprazole. Recent studies have questioned the clinical importance of this effect. Alternatively, a H₂-receptor antagonist (except cimetidine) can be used.

What risk factors does this patient have for myopathy with a statin?

According to the prescribing notes on Statins (section 2.12, BNF 60), he is at increased risk of myopathy because he is receiving high-dose atorvastatin and he has a high intake of alcohol. The patient should be advised to report any unexplained muscle pain and to reduce his intake of alcohol. He should also be advised to make other lifestyle modifications to reduce his cardiovascular risk that include beneficial changes to diet, exercise, and weight management. He should be advised to stop smoking and given access to interventions for smoking cessation. His dose of atorvastatin should be reviewed after 6−12 weeks.