Clinical articles

In a previous issue of the BJC, key issues regarding the use of high-sensitivity troponin and its use in clinical context were raised.¹ Despite the clear benefits with regards to earlier identification of ‘troponin-positive patients’, it is vital to highlight that troponin is specific for myocardial injury, but is not specific for the diagnosis of acute myocardial infarction (MI). Echocardiography is increasingly being used in cases where a ‘troponin-positive event’ is out of keeping with the history and examination for a type I MI. Competent use of this imaging modality can have drastic alterations in the management of patients and potentially prevent invasive cardiological procedures that may later provide more risk than benefit. This case report highlights the caution we must take when requesting troponin biomarkers and the use of echocardiography to aid in the management of the haemodynamically unstable patient.

This study aimed to assess mortality and cardiovascular (CV) outcomes of patients with newly diagnosed atrial fibrillation (AF) managed in the UK primary care setting. Electronic patient records in The Health Improvement Network were used to identify incident AF (n=9,418, 52.1% male, mean age 73.8 years [standard deviation 11.2]) and matched (gender, age and locality) controls (n=47,090) aged ≥40 years. Three main study outcomes were assessed within two years of follow-up: incident CV outcomes, CV mortality and all-cause mortality. AF cases had an increased risk of developing all investigated CV outcomes when compared with controls (systemic hypertension relative risk [RR]=1.9 [95% confidence interval 1.7–2.1]; peripheral thromboembolic events RR=2.0 [1.8–2.4]; congestive heart failure RR=13.1 [11.5–14.8]; valvular heart disease RR=7.0 [6.0–8.1]; ischaemic heart disease RR=4.3 [3.8–4.8]; stroke RR=3.7 [3.3–4.2]; myocardial infarction RR=3.1 [2.6–3.6]). AF patients were also twice (RR=2.0 [1.8–2.1]) as likely to die from all causes and almost three times (RR=2.7 [2.4–3.1]) more likely to die from CV reasons than controls. AF cases demonstrated consistently worse prognosis across all of the main outcomes assessed when compared with the control patients. 

Hypoglycaemia is defined as a lower than normal level of blood glucose, and in patients on glucose-lowering therapy, defined as glucose levels less than 4 mmol/L. In the UK, it is usually classified as ‘mild’, if the episode is self-treated, or ‘severe’, if the individual requires third-party assistance. However, the American Diabetes Association definition of hypoglycaemia is different.¹ They classify hypoglycaemia into five categories. These are shown in table 1. 

Earlier reports suggest differences in presentation between South Asians and white Europeans experiencing acute coronary syndromes. To compare the demographics and presentation of British South Asians, a long-term prospective survey of a consecutive series of British South Asians was conducted. South Asian patients were analysed as six distinct subgroups, with an overall comparison to a white European cohort.

South Asian patients were of similar mean age, and male predominance (66%), across all subgroups, but as a whole, were younger (62 ± 13 years) than white Europeans (69 ± 14 years), p<0.001. Diabetes was markedly more prevalent in South Asians (range 42–55%) compared with white Europeans (17%), p<0.001. South Asians, as a whole, reported a larger average area of discomfort (5.2 ± 3.5) than did white Europeans (4.4 ± 3.1), p<0.001. Posterior chest discomfort was reported by 38% of all South Asians (range 35–44%) and by 25% of white Europeans, p<0.001. The average intensity of discomfort was similar between white Europeans (6.4 ± 3.2) and South Asian cohorts (6.4 ± 3.0), p=0.80. Differences in ‘intensity of discomfort’ between South Asian subgroups did not reach significance. Silent cardiac events were more common in white Europeans (12.7%) than in South Asians (9.0%), p<0.001.

In conclusion, Asian patients were younger, more likely to be diabetic and tended to report discomfort over a greater area of their body, than did white Europeans. No differences were found between individual South Asian subgroups for pain distribution (extent), character or intensity. South Asian women tended to report a wider distribution of discomfort and intensity than did men across all subgroups.

We present an investigation into the use of electrocardiograms (ECGs) in an emergency setting.

Providing cardiopulmonary bypass and surgical back-up for transcatheter aortic valve implantation has significant implications for surgical services. It is unclear how practice varies around the UK and whether valve-type influences practice. We performed an email-based survey to gain a UK-wide snapshot of current practice. We found that bypass was available in the catheter lab in 94% of Edwards versus 30% of CoreValve centres (p=0.0003), and that a full surgical team and theatre were kept free in 89% of Edwards versus 20% of CoreValve centres (p=0.008). Further research is required to understand whether this difference in surgical provision, related to valve-type, confers outcome benefit.

To determine whether the ‘smoker’s paradox’ exists in the acute coronary syndrome (ACS) population, we performed the first meta-analysis of adjusted risk estimates separately for early and late mortality. Eligible studies were comparative studies of smokers versus non-smokers enrolling patients hospitalised for ACS and reporting adjusted risk estimates for all-cause mortality.

Twenty-six risk-adjusted studies of smokers versus non-smokers enrolling >700,000 patients with ACS were identified and included. Pooled analysis suggested that smoking was associated with a statistically significant reduction in early (in-hospital or 30-day) mortality for the comparison of current versus never smokers (odds ratio [OR] 0.85; 95% confidence interval [CI] 0.75 to 0.96), any comparisons (current vs. never, former vs. never, current vs. former/never, and current/former vs. never smokers; OR 0.89; 95% CI 0.84 to 0.94), and patients with exclusive ST-segment elevation myocardial infarction (OR 0.80; 95% CI 0.73 to 0.87) and acute myocardial infarction (OR 0.87; 95% CI 0.82 to 0.92). Smoking was associated with a statistically non-significant increase in late mortality for any comparisons (hazard ratio 1.07; 95% CI 0.95 to 1.21).

In conclusion, the ‘smoker’s paradox’ for mortality may exist in the early phase following ACS but it may vanish in the late phase.

We present an investigation into the safety of providing training in coronary angiography within a district general hospital setting.

An unusual case of endomyocardial fibrosis presenting secondary to idiopathic hypereosinophilic syndrome, diagnosed with the aid of cardiovascular magnetic resonance (CMR) imaging. This case highlights how CMR imaging is a powerful addition to current non-invasive diagnostic tools, for early clinical diagnosis of eosinophilic endomyocardial disease, and may potentially obviate the need for cardiac biopsy in the future.

Lipoproteins play a pivotal role in the development of atherosclerosis, where apolipoprotein B-containing lipoproteins are considered pro-atherogenic and high-density lipoprotein anti-atherogenic. The retention and accumulation of modified low-density lipoprotein in foam cells within the intima of the arterial vessel wall is characteristic of the atherosclerotic process. Conversely, high-density lipoprotein plays an important role in the efflux of excess free cholesterol from the arterial wall through the process of reverse cholesterol transport. High-density lipoprotein also has antioxidant and anti-inflammatory properties that may also confer a protective effect on the vasculature. Statins are the first-line treatment for lowering low-density lipoprotein, but the residual risk of disease remains high. Novel therapies are under investigation that may offer a new therapeutic approach to treating atherosclerosis and additional protection against cardiovascular disease.