Clinical articles

We summarise recent developments in minimally invasive cardiac surgery. We describe the modifications to anaesthetic technique, incisions, cardiopulmonary bypass and myocardial protection, and the endoscopic and robotic adjuncts that permit coronary artery surgery, valve repair and replacement, and repair of descending aortic aneurysms to be successfully carried out. The results for such surgery are summarised and compared to conventional open techniques as well as percutaneous procedures.

Low-density lipoprotein cholesterol (LDL-C) reduction alone has consistently achieved a statistically significant 25–30% reduction in clinical events in multiple clinical trials. This degree of clinical benefit is inadequate, however, to stem the tide of coronary artery disease. A focus on low-density lipoprotein (LDL) reduction alone reduces the rate of coronary atherosclerosis progression but leaves a large number of patients experiencing clinical events despite adequate LDL-C control. One major contributor to coronary atherosclerosis that is not improved with LDL reduction is high-density lipoprotein (HDL) and reverse cholesterol transport.

Clinical trials funded by the US National Institutes of Health (NIH) have demonstrated that a combination of LDL reduction and HDL increase can achieve better clinical and arteriographic outcomes compared to LDL reduction alone. HDL heterogeneity helps to explain differences in the efficiency of reverse cholesterol transport. This process can be enhanced through appropriate diet, loss of excess body fat and physical activity. Nicotinic acid and fibric acid derivatives can enhance reverse cholesterol transport and have been used in multiple clinical trials. The combination of nicotinic acid and a statin drug are particularly beneficial in NIH-sponsored clinical trials. The HDL increase induced by nicotinic acid is primarily HDL2. By combining a two-staged LDL-C reduction and HDL-C raising strategy, improved clinical outcomes can be achieved for patients with coronary artery disease.

Referral to cardiac rehabilitation (CR) is often incomplete. Those most likely to benefit are less likely to be offered the service and there has been little systematic exploration of the reasons for this situation in the UK. The purpose of this study was to investigate CR staff perceptions in relation to aspects of referral to CR programmes. In a prospective cross-sectional study, a 24-item questionnaire regarding perceptions of referrals was mailed to 115 referring staff of 23 CR out-patient programmes in the North West of England. The response rate was 85 (74%). The most common factors cited for low referrals were: funding limitation 57 (67%), limited facilities 56 (66%), shortage of trained staff 51 (60%) and patients” poor physical ability 50 (59%). Fifty-three (62%) respondents suggested participation would increase if CR were offered by a medical practitioner. Sixty-one (72%) respondents felt they provided CR according to recommended guidelines. Seventy-nine (93%) of the respondents agreed CR was necessary or appropriate for most cardiac patients and 76 (89%) reported CR offered more to patients than secondary prevention. The study concludes that CR programmes should be audited better and physicians need to be more actively involved in recruiting patients to programmes. Better funding is required to increase facilities and staff training to improve referral of patients.

Cardiac catheterisation access site complications are common. Their incidence depends on various risk factors such as female gender, nadir platelet count, diagnostic versus therapeutic intervention, excessive anticoagulation and so on. Thrombotic complications are common at the brachial site and haemorrhagic complications are more common at the femoral site. In spite of new devices for securing haemostasis, the incidence of these complications has not decreased. We report the case of a 71-year-old, obese woman who died secondary to femoral access site haemorrhage despite all surgical attempts. This case emphasises the need for a tailor-made approach for deciding the site of access.

The current national target in the UK for total cholesterol is 5 mmol/L. The Primary Care Data Quality (PCDQ) programme reported in 2002 that only 50% of patients with coronary heart disease (CHD) achieved the 5 mmol/L target and we report on progress since then. Routinely collected general practice computer data were extracted in two successive data collections in 2003 and 2004/05 and analysed. The standardised prevalence of CHD recorded in GP computer systems rose from 3.8% to 4.0% from 2002 to 2004/5. In patients with CHD, cholesterol recording rose from 47.6% to 89.0%, the percentage of patients receiving a statin rose from 49.4% to 71.5% and mean cholesterol levels fell from 5.18 to 4.67 mmol/L. The proportion of CHD patients with a cholesterol recording achieving the 5 mmol/L target increased from 44.7% to 67.7%. Overall, 53.1% of patients with cardiovascular disease had total chol-esterol below 5 mmol/L. Patients with CHD achieved better cholesterol control than those with stroke (4.87 mmol/L) or peripheral vascular disease (PVD) (4.79 mmol/L) and a higher percentage of patients achieved the 5 mmol/L target (60.1% versus 43.3% and 49.9% respectively). There remains scope for improved management of cholesterol in primary care and greater efforts are needed to see that more patients with cardiovascular disease benefit from best practice.

The British Heart Foundation (BHF) diary has been designed to be a personal record for patients post-myocardial infarction (MI) to record their progress, keep a record of their condition, provide guidance on services and basic information on medication and risk factors, and to provide pages that the patient can use to manage their condition.

Studies indicate that increased heart rate is a risk factor for ischaematic cardiac events; accordingly heart rate reduction may improve outcome. Beta blockers and some calcium channel blockers reduce heart rate but their use may be limited by negative inotropic effects and several contraindications. Ivabradine, a selective sinus node If channel inhibitor, represents a therapeutic innovation in the treatment of ischaemia. Preclinical and early clinical studies show that ivabradine can reduce heart rate without affecting cardiac systolic function, suggesting that If inhibition may be an effective approach to minimise both angina and the underlying ischaemia. In clinical studies ivabradine has anti-anginal and anti-ischaemic effects in patients with stable angina and has comparable efficacy to atenolol and amlodipine. This anti-ischaemic effect is also observed in elderly patients in whom there is a greater incidence of stable angina. Furthermore, the absence of additional cardiac effects associated with If inhibition suggest that this approach may be effective in other patient groups, such as those at risk of acute coronary events or compromised left ventricular function. Further clinical trials with ivabradine to evaluate fully the therapeutic potential of If inhibition are ongoing.

Coronary heart disease (CHD) remains the leading cause of premature death in the United Kingdom. The mortality from myocardial infarction (MI) can be reduced by reperfusion of the infarct-related artery with thrombolytic agents.2,3 The best results for survival are achieved in those patients who are thrombolysed early.4,5 We set out to investigate whether the time between arrival to hospital of a patient with acute MI and administration of thrombolytic therapy (door-to-needle time) could be improved by the introduction of a bolus thrombolytic in the accident and emergency (A&E) department in a busy inner city hospital. This study of 13 months’ duration compared the door-to-needle times and the proportion of patients thrombolysed within 30 minutes before and after the introduction of a bolus thrombolytic agent – reteplase. The findings demonstrated a 37% reduction in door-to-needle time (from 27 minutes to 16 minutes) and a 22% improvement in the proportion of patients thrombolysed within 30 minutes (from 68% to 86%) with reteplase. Our findings suggest that bolus thrombolytic agents such as reteplase can be used in a strategy to meet the National Service Framework (NSF) targets for door-to-needle time.

Converging from a number of disciplines, non-linear systems theory and, in particular, chaos theory, offers new descriptive and prescriptive insights into physiological systems that may more accurately reflect underlying mechanisms. This paper describes the implications of these new perspectives and briefly outlines how they might be applied to the study of cardiology.

In an observational study, we sought to determine the effect of applying the Duke’s treadmill score on patient assessment and prioritisation to coronary angiography waiting lists within a rapid access chest pain clinic in a UK district general hospital.

After attending the rapid access chest pain clinic, patients requiring subsequent coronary angiography were placed on either an urgent or a routine waiting list. We determined the number of patients subsequently shown to have severe coronary artery disease (left main stem or three-vessel disease) in both waiting lists. We then assessed the effect of applying the Duke’s treadmill score retrospectively on these patients to produce regraded waiting lists (urgent and routine); these were compared with the actual lists generated clinically.

The actual urgent list had 43/111 (39%) patients with severe disease; the actual routine list had 28/98 (29%) patients with severe disease (p=NS). Application of the Duke’s treadmill score to produce re-graded lists reduced the total number of patients on the urgent list from 111 to 68. Thirty-three of 68 (49%) patients on the Duke’s treadmill score urgent list had severe disease compared to 43/111 (39%) on the actual urgent waiting list. Specificity for allocating patients with severe disease to the urgent waiting list improved from 50% to 75% by application of the Duke’s treadmill score compared with the clinically generated list.

Thus, the Duke’s treadmill score could be used in a rapid access chest pain clinic to prioritise patients objectively for cardiac catheterisation in a resource-limited system.