Clinical articles

Scotland has one of the highest mortality rates for ischaemic heart disease (IHD) in the world, accounting for one quarter of all deaths. Much evidence demonstrates aggressive management of risk factors can make a significant difference to this high morbidity and mortality. Current evidence suggests that secondary prevention of IHD is currently not carried out well in primary care in the UK. Our practice set out to see if this could be improved by using computer records. Over the course of four years more than 80% of IHD patients are now on aspirin, almost 90% have blood pressure recorded annually (average 130/74 mmHg), 82% are non-smokers, 84% have an annual cholesterol check, 65% have a cholesterol < 5 mmol/L, 56% are on a cholesterol-lowering drug (average cholesterol is 4.76 mmol/L), 61% are on cardioprotective drugs, and there was one acute infarct. We suggest that secondary prevention can be improved at a practice level with a good recording system, and a motivated primary care team.

Angina pectoris occurs in 30–40% of patients with aortic stenosis, despite a normal coronary circulation. This along with syncope, classically occurs during exercise. There are a number of suggested pathophysiological mechanisms for these symptoms, all of which lead to an imbalance between myocardial oxygen supply and demand. We report an 81-year-old patient who had several episodes of chest pain occurring at rest, leading to syncope resulting in electro-mechanical disassociation (EMD) cardiac arrest. The electrocardiogram (ECG) during these episodes showed profound ST depression, leading to the hypothesis that the underlying pathophysiology was due to myocardial ischaemia caused by the aortic stenosis alone.

Sibutramine is one of two anti-obesity agents approved by the National Institute of Clinical Excellence. It inhibits the re-uptake of noradrenaline and serotonin in the brain. By enhancing the sensation of satiety after a meal and reducing the fall in basal metabolic rate which usually occurs during weight loss, sibutramine is a useful aid to achieving weight loss and weight maintenance. Randomised controlled trials have shown that sibutramine 10 mg/day, in combination with diet and exercise, produces and maintains a dose-related weight loss of 5–10% in the majority of obese patients studied. This is accompanied by a range of important health benefits, including improvements in cholesterol and triglyceride levels.
Adverse publicity led to the European Commission’s Committee for Proprietary Medicinal Products recently carrying out an in-depth investigation into the use of sibutramine in over 12,000 patients across Europe. Its findings support the use of sibutramine in obesity management, with no causal link found between the use of the drug and mortality. No change has been made to the Summary Product of Characteristics regarding the cardiovascular safety of sibutramine and the drug has been re-instated for use in Italy.
Prescribers should be aware of the cautions surrounding sibutramine use. While it is not advisable for those with a history of coronary heart disease or cardiac arrhythmias, published data reveal that most patients on sibutramine experience a drop in blood pressure and it may be used safely in patients with controlled hypertension. A small number of patients treated may show increases in blood pressure, particularly those who appear to be non-responders. Regular blood pressure monitoring is therefore advised.

Almost a half of all myocardial infarctions occur in those over 70 years of age and this is projected to rise further as the number of older patients in the total population increases. Following myocardial infarction, complications are more common in the older patient and the mortality outlook is much worse in those aged over 75 years. Guidelines generally favour the administration of thrombolysis post-myocardial infarction to older patients, although there is a lack of randomised clinical trials with thrombolysis in this group. Observational data, however, suggest that there is a significantly increased risk of mortality in patients aged over 75 years and this means the elderly are less likely to receive thrombolytic therapy, even when no contraindications are present. Randomised trials have shown that percutaneous coronary intervention is associated with a better outcome in the older patient. With the advances in antiplatelet therapy and the advent of intracoronary stents, this outcome is expected to improve further. The article also discusses therapeutic options in secondary prevention.

Clinical and epidemiological studies suggest elevated levels of total plasma homocysteine (> 15 µmol/L) are associated with an increased risk of cardiovascular disease, independent of other known risk factors. This review outlines the causes of hyperhomocysteinaemia, current evidence of a positive association with cardiovascular disease, and how such findings may have important implications for future assessments of risk and nutritional recommendations, particularly for those with a previous or family history of cardiovascular disease.

Modest elevations in plasma homocysteine from either genetic or acquired causes appear to relate to cardiovascular disease on the basis of strong epidemiological evidence. We know that homocysteine can be lowered with varying doses of folic acid, with or without vitamins B6 and B12, although we do not yet know the potential cardiovascular benefit of vitamin supplementation in these subjects. Several multicentre interventional trials are underway to address this question and, until these are complete, we recommend a healthy diet high in folate replete foodstuffs. We also recommend oral folic acid supplements in some subjects with cardiovascular disease and high homocysteine, mindful that definitive evidence of benefit is lacking.

The evidence for ambulatory blood pressure measurement (ABPM) as an indispensable investigation in clinical practice is now overwhelming. For years the argument against ABPM has been based on a lack of evidence showing the technique was superior to conventional measurement in predicting outcome. There is now ample evidence from longitudinal studies that ABPM is a much stronger predictor of cardiovascular morbidity and mortality than conventional measurement.1 Moreover, though the relevance of nocturnal hypertension has been a controversial topic, recent evidence has shown that a non-dipping nocturnal pattern is a strong independent risk for cardiovascular mortality.

The study aim was to compare clinic and 24-hour ambulatory blood pressure monitoring, and to determine the influence of the latter on the management of a group of patients with variable or uncontrolled blood pressure. A retrospective data analysis was carried out on patients selected from out-patient clinics at New Cross Hospital. One hundred and seventy-one patients with uncontrolled or variable blood pressure underwent 24-hour ambulatory blood pressure monitoring and 153 results were analysed.
Following ambulatory blood pressure monitoring, 56% of the patients had their treatment regimens either decreased, unaltered or did not require antihypertensive therapy. The study found 24-hour ambulatory blood pressure monitoring helps in the assessment of overall 24-hour blood pressure control of patients and may also help in the better management of difficult groups of patients.

Glucose-insulin-potassium (GIK) therapy addresses the metabolic changes of ischaemia secondary to acute myocardial infarction. These changes include elevated plasma free fatty acid concentration and glucose intolerance. A meta-analysis of trials from the pre-thrombolysis era showed a significant reduction in the number of deaths in the GIK group in comparison to placebo (16.1% vs. 21% respectively, p=0.004). High-dose GIK therapy was found to be of particular benefit.
Three randomised trials in the post-thrombolysis era have been published, with variable results. The DIGAMI study (in diabetics) and the ECLA pilot trial had positive results: in the latter there was a 60% reduction in in-hospital mortality in patients who received GIK therapy plus reperfusion. By contrast, the Pol-GIK trial was negative.
Outstanding questions include the usefulness of GIK therapy and beta blockade in the presence of thrombolysis or primary angioplasty. GIK therapy and beta blockade might act in complementary fashion to antagonise the metabolic changes of ischaemia while thrombolysis or angioplasty improve early reperfusion and limit infarct size. Patients with acute coronary syndrome might benefit more from GIK therapy since they have some coronary flow.

A significant left main coronary artery (LMCA) stenosis is an important predictor of survival in patients with coronary artery disease. In the past, percutaneous coronary intervention (PCI) was generally restricted to patients with protected left main disease; and >50% stenosis of the LMCA was a contraindication to balloon angioplasty.
In the pre-stent era, results of left main balloon angioplasty were poor. For example, in one series, in-hospital mortality was 9.1% in the elective group and 50% in the acute group. The development of coronary stenting and effective antiplatelet therapy in the 1990s stimulated renewed interest in PCI for LMCA disease. A number of studies reported good outcomes for protected LMCA lesions, though results in haemodynamically unstable patients remained poor.
The figures for a number of studies of elective PCI for unprotected left main stenosis are also described. The best documented outcomes so far are one-year actuarial survival of 89% in high-risk patients and 98% in low-risk patients.
If severe calcification is obvious on angiography or ultrasound then debulking seems sensible. The data suggest that directional coronary atherectomy alone or with stenting may be associated with reduced restenosis rates.
The use of glycoprotein IIb/IIIa inhibitors and drug-eluting stents may further improve the outlook for patients with LMCA stenosis.