Ireland has the highest mortality rate from ischaemic heart disease in males and the third highest rate in females in the European Union. In this article, I will discuss the role of the GP in the management of the patient who has had a recent myocardial infarction (MI). 

Acute myocardial infarction can be defined from a number of different perspectives. This article will mainly be concentrating on patients who have had recent ischaemic symptoms and persistent ST-segment elevation on the ECG (STEMI). Most of this presentation is based on the advice given in the 2008 guidelines on the management of STEMI of the European Society of Cardiology (ESC).¹

Rehabilitation

Post-myocardial infarction care begins as soon as possible after admission, with the patient being offered a place on a cardiac rehabilitation programme. These programmes are based in the hospital and are attended by the patient while an inpatient, and in the succeeding weeks after discharge as an outpatient. Cardiac rehabilitation can be defined as a professionally supervised programme to help people recover from MI. It provides education and counselling services to help heart patients increase physical fitness, reduce cardiac symptoms, improve health and reduce the risk of future heart problems, including heart attack. The patient is then discharged with a written summary to the care of the GP.

First consultation

When the practical issues of the discharge summary and prescription have been dealt with, the GP should ask a few open-ended questions to establish how the patient feels about his recent experiences. Anxiety is almost inevitable, in both patients and their families, and reassurance and explanation of the nature of the illness is of great importance. Printed information in the form of a patient leaflet such as ‘All about your heart... and stroke’ from the Irish Heart Foundation (IHF) is especially helpful. Alternatively, an advice sheet can be downloaded from a website, eg. www.patient.co.uk

The GP must also be on the alert for the occurrence of depression and irritability, which frequently occur after returning home. He should also recognise that denial is common and may make subsequent acceptance of the diagnosis difficult. Lifestyle advice is important and the possible causes of coronary artery disease should be discussed with the patient and their partner, with individualised advice on a healthy diet, weight control, smoking, and exercise given. 

The GP is sometimes asked about driving post-MI. The current edition of Medical Aspects of Driver Licensing: A Guide for Registered Medical Practitioners 2010, published by the Road Safety Authority, states that persons who have suffered myocardial infarction may be certified as being fit to drive subject to regular medical review. More precise information is given in the UK publication from the Drivers’ Medical Group, Driving and Vehicle Licensing Agency (DVLA), which states the following for persons who have had a STEMI:

If successfully treated by coronary angioplasty, driving may recommence after a week, provided that:

• No other urgent revascularisation is planned 
• Left ventricular ejection fraction (LVEF) is at least 40% prior to hospital discharge
• There is no other disqualifying condition. If not successfully treated by coronary angioplasty, driving may recommence after four weeks provided: 
• There is no other disqualifying condition. 

DVLA need not be notified.

With regard to air travel, a person who has had an MI without complications can usually travel by air within two to three weeks. Patients who have had a complicated MI need expert individual advice. 

The GP is in a good position to raise the subject of sexual activity. He can reassure the patients that after recovery from an MI, sexual activity presents no greater risk of triggering a subsequent MI than if they had never had an MI. Also, patients who have made an uncomplicated recovery after their MI can resume sexual activity when they feel comfortable to do so, usually after about four weeks. Occasionally, the issue of erectile dysfunction arises, especially as these patients are usually on beta blockers. Generally, it is better to wait six months and if the patient is stable, a phosphodiesterase type5 (PDE5) inhibitor may be prescribed. Obviously, PDE5 inhibitors must be avoided in patients treated with nitrates and/or nicorandil as this can lead to dangerously low blood pressure.

Secondary prevention

Coronary heart disease is a chronic condition, and patients who have recovered from a STEMI are at high risk for new events and premature death. Eight to 10% of post-infarction patients have a recurrent infarction within a year after discharge, and mortality after discharge remains much higher than in the general population. Several evidence-based interventions can improve prognosis. 

The long-term management of this large group of patients is the responsibility of the GP, and these interventions will have a higher chance of being implemented if the GP has a management protocol in place in the practice.

Smoking cessation

Evidence from observational studies shows that those who stop smoking reduce their mortality in the succeeding years by at least one-third, compared with those who continue to smoke. Stopping smoking is potentially the most effective of all secondary prevention measures, and much effort should be devoted to this end. While most patients do not smoke during the acute phase of a STEMI for obvious reasons, resumption of smoking is unfortunately quite common after returning home. 

Data from the National Programme in General Practice for the Secondary Prevention of Cardiovascular Disease in Ireland (Heartwatch) showed that 13% of patients who had had a cardiac event (defined as MI, percutaneous coronary intervention (PCI), ie. coronary angioplasty or coronary artery by-pass graft) smoked at the first visit to their GP and that 10% of these were still smoking at their sixth visit 18 months later. All patients who smoke should be advised to quit and be offered assistance with same. The ‘five As’ strategy is very helpful in this regard:

• Ask: Systematically identify all smokers
• Assess: Determine the smoker’s degree of addiction and his or her readiness to quit – the ‘stages of change’ model proposed by Prochaska and DiClemente is very helpful here
• Advise: Strongly urge all smokers to quit
• Assist: Agree on a smoking cessation strategy, including behavioural counselling, nicotine replacement therapy and/or pharmacological intervention. Printed leaflets from the Health Promotion Unit and the IHF are very helpful. Also, in selected cases, the assistance of a smoking cessation officer from the local health promotion unit should be sought
• Arrange: Follow-up or refer to smoking cessation programme.

Diet

The guidelines recommend the following:

• Eat a wide variety of foods
• Adjust calorie intake to avoid overweight
• Increase consumption of fruit and vegetables, along with wholegrain cereals and bread, fish (especially oily), lean meat, and low-fat dairy products 
• Replace saturated and trans fats with monounsaturated and polyunsaturated fats from vegetable and marine sources and reduce total fats to < 30% of total calorie intake, of which less than one-third should be saturated 
• Reduce salt intake if blood pressure is raised. Many processed and prepared foods are high in salt, and in fat of doubtful quality.

Omega-3 polyunsaturated fatty acids

The role of omega-3 fatty acid supplements for secondary prevention has been studied in an open-label randomised study in patients post-myocardial infarction – the GISSI prevenzione trial. In this study, 1g daily of fish oil on top of a Mediterranean diet significantly reduced total and cardiovascular mortality. 

Weight control

Obesity is an increasing problem in patients with STEMI. At least one-third of European women and one in four men with acute coronary syndromes below the age of 65 have a body mass index (BMI) of > 30kg/m2. Current ESC Guidelines define a BMI < 25kg/m2 as optimal and recommend weight reduction when BMI is 30kg/m2, or more, and when waist circumference is > 102/88cm (men/women) because weight loss can improve many obesity-related risk factors. The leaflet ‘Are you ready to lose weight?’ from the IHF is helpful here. Again, the assistance of a community-based dietitian can be helpful in some cases.

Physical activity

All patients should be given advice with regard to physical activity based on their recovery from the acute event, taking into account their age, their pre-infarction level of activity, and their physical limitations. As a general rule, patients should be advised to be physically active for 20-30 minutes a day to the point of slight breathlessness. Those who are not achieving this should be advised to increase their activity in a gradual step-by-step fashion, aiming to increase exercise capacity. They should start at a level that is comfortable and increase the duration and intensity of activity as they gain fitness. The leaflet ‘Get active for a happy heart’ from the IHF is especially helpful.

Aspirin and anti-platelet drugs

A 25% reduction in reinfarction and death in post-infarction patients has been demonstrated with aspirin in dosages ranging from 75 to 325mg daily. There is, however, evidence that the lower dosages are effective, with fewer side-effects. Thus, aspirin should be offered to all patients immediately on diagnosis of an MI, and should be continued indefinitely afterwards. 

There is abundant evidence on the usefulness of clopidogrel as an adjunctive antiplatelet therapy on top of aspirin in patients undergoing PCI. Thus, clopidogrel in a loading dose of at least 300mg will be given as soon as possible in addition to soluble aspirin 300mg to all patients with STEMI undergoing PCI. Similarly, patients treated with a standard fibrinolytic regimen are given a 300mg clopidogrel loading dose on top of aspirin. These patients are usually continued on a combination of aspirin 75mg and clopidogrel 75mg on discharge from hospital. Frequently, the GP finds himself in the dilemma of wondering when to stop the clopidogrel, especially as the optimal duration of dual treatment after STEMI has not been determined. 

However, considering the long-term effect of clopidogrel in patients after a non-ST-segment acute coronary syndrome in the CURE trial and taking into account the current recommendation for non-STEMI patients, where STEMI patients are treated with a combination of aspirin and clopidogrel during the first 24 hours after the MI, a treatment duration of 12 months is now recommended whether or not a stent has been placed. 

Thereafter, standard treatment including low-dose aspirin should be given, unless there are other indications to continue dual antiplatelet therapy, for example in patients who have received a drug-eluting stent, although this issue is still not fully resolved by specific studies.

ACE inhibitors and angiotensin receptor blockers

Several trials have established that ACE-inhibitors reduce mortality after STEMI with reduced residual left ventricular (LV) function. Thus, ACE inhibitors will be prescribed to patients who have experienced heart failure in the acute phase, even if no features of this persist, who have an ejection fraction of < 40%, or a wall motion index of > 1.2, provided there are no contraindications, and should be continued indefinitely by the GP. 

While there are observations from studies in populations with stable cardiovascular disease but without LV dysfunction showing beneficial effects from the use of ACE-inhibitors, including a reduction in mortality and stroke, their long-term use cannot be considered to be mandatory in post-STEMI patients who are normotensive, without heart failure or compromised systolic LV function. 

Angiotensin receptor blockers (ARBs) were evaluated in the context of STEMI as alternatives to ACE-inhibitors in the VALIANT trial where they were compared with valsartan alone (160mg twice daily), full-dose captopril (50mg three times daily), or both (80mg twice daily and 50mg three times daily). Mortality was similar in the three groups, but discontinuations were more frequent in the groups receiving captopril. 

Therefore, valsartan in dosages as used in the trial represents an alternative to ACE-inhibitors in patients who do not tolerate ACE-inhibitors and have clinical signs of heart failure and/or an ejection fraction < 40%. 

ACE or ARB therapy may require to be titrated upwards by the GP and, if so, this should be at short intervals (for example every one to two weeks) until the maximum tolerated or target dose is reached. 

Renal function, serum electrolytes and blood pressure should be measured within one or two weeks of starting treatment and after each dosage increase, and then at least annually. More frequent monitoring may be needed in patients who are at increased risk of deterioration in renal function.

Beta blockers

Beta blockers reduce mortality and reinfarction by 20-25% in those who have recovered from an infarction. Most of these trials have been performed in the pre-reperfusion era. 

A meta-analysis of 82 randomised trials provides strong evidence for long-term use of beta blockers to reduce morbidity and mortality after STEMI even if ACE-inhibitors are co-administered. 

The significant mortality reductions observed with beta blockers in heart failure in general further support the use of these agents after STEMI. 

Beta blockers should be prescribed indefinitely by the GP in all patients who have recovered from a STEMI and do not have a contraindication. 

Aldosterone blockade

In the EPHESUS trial, where 6,642 post-STEMI patients with LV dysfunction and heart failure or diabetes were randomised to eplerenone, a selective aldosterone blocker, or placebo, there was a 15% relative reduction in total mortality and a 13% reduction in the composite of death and hospitalisation for cardiovascular events. However, serious hyperkalaemia was more frequent in the group receiving eplerenone. 

Thus, aldosterone blockade may be prescribed in the hospital for post-STEMI patients with LV dysfunction and heart failure or diabetes and be continued on discharge. If so, the GP should perform routine monitoring of serum potassium and should be particularly careful if prescribing other potential potassium-sparing agents in these patients.

Blood pressure control

According to the ESC guidelines for the management of arterial hypertension, the goal is to achieve a blood pressure 130/80mmHg in patients with stroke, myocardial infarction, renal disease, and diabetes. Pharmacotherapy recommended post-STEMI (beta blockers, ACE-inhibitors, or ARBs) will help to achieve these goals, in addition to lifestyle modification with respect to physical activity and weight loss. The GP may have to prescribe additional pharmacotherapy to achieve this goal as needed.

Management of diabetes

Glucometabolic disturbances are common in patients with coronary disease and should be actively searched for. Since an abnormal glucose tolerance test is a significant risk factor for future cardiovascular events after myocardial infarction, this should ideally be done in hospital before or by the GP after discharge. 

In patients with established diabetes, the aim is to achieve HbA1c levels < 6.5%. This calls for intensive modification of lifestyle (diet, physical activity, weight reduction), usually in addition to pharmacotherapy. In patients with impaired fasting glucose level or impaired glucose tolerance, lifestyle changes only are currently recommended.

Interventions on lipid profile

Several trials have unequivocally demonstrated the benefits of long-term use of statins in the prevention of new ischaemic events and mortality in patients with coronary heart disease. 

The targets established by the Fourth Joint Task Force of the ESC and other societies in patients after infarction are: for total cholesterol, 4.5mmol/l with an option of 4.0mmol/l if feasible, and for lower LDL cholesterol, 2.5mmol/l with an option of 2.0mmol/l if feasible. Although pharmacological treatment is highly efficient in treating dyslipidaemia in heart disease, diet remains a basic requirement for all patients with coronary heart disease. 

More intensive lipid-lowering treatment has been compared with standard lipid-lowering therapy in a recent meta-analysis of randomised controlled trials of different intensities of statin regimens in a total of 29,395 patients with coronary artery disease. Compared with less intensive statin regimens, more intensive regimens further reduced LDL cholesterol levels and reduced the risk of myocardial infarction and stroke. 

The analysis supports the use of more intensive statin regimens in patients with established coronary artery disease. However, there is insufficient evidence to advocate treating to particular LDL cholesterol targets, using combination lipid-lowering therapy to achieve these targets. In patients who do not tolerate statins, other lipid-lowering therapy with fibrates (gemfibrozil, bezafibrate) may be warranted, particularly in patients with high triglycerides at baseline. Ezetimibe, a compound which reduces cholesterol uptake from the intestine, decreases LDL cholesterol (and CRP), but there are no clinical data to support its current use in STEMI survivors. 

Influenza vaccination

Influenza immunisation is indicated in all patients with coronary artery disease and thus also in those surviving a STEMI.

Role of GPs

The 2008 guidelines on the management of STEMI of the European Society of Cardiology place emphasis on lifestyle measures and provide helpful advice on the drug management of this group of patients. 

It is especially important that GPs and practice nurses are aware of the
importance of BP control management, diabetes, statins, omega-3 fatty acids, aspirin, clopidogrel, ACE-inhibitors, beta blockers, aldosterone blockade, and influenza vaccination when they are following up STEMI patients.

References

1. Management of acute myocardial infarction in patients presenting with persistent ST-segment elevation. www.escardio.org/guidelines-surveys/esc-guidelines/GuidelinesDocuments/guidelines-AMI-FT.pdf