Clinical articles

Contrast-induced nephropathy is the third most common cause of in-hospital acute kidney injury and accounts for 10% of total cases. It is commonly encountered following coronary angiography and this systematic review aims to use current evidence to ascertain which treatment modalities are most effective in the prevention of the disease. 

A PubMed literature search was conducted in March 2014 using search terms, ‘contrast nephropathy and coronary angiography’. The data analysed included 15 trials and two meta-analyses in order to determine whether patients given N-acetylcysteine (NAC), sodium chloride or sodium bicarbonate had better clinical outcomes. Study data were reviewed and quality of data discussed. 

Current data indicate that sodium bicarbonate is as effective as sodium chloride when used in patients with estimated glomerular filtration rate (eGFR) <60 ml/min. NAC adds no statistically significant benefit in mild-to-moderate renal disease regardless of whether it is used in isolation or as an adjunct therapy with fluid.

The European Medicines Agency (EMA) has mandated that patients treated with dronedarone have regular monitoring. An arrhythmia specialist nurse (ASN) took over the care of patients on dronedarone in 2012.

Patients on dronedarone were identified from hospital notes and pharmacy records. Adherence to EMA guidelines on monitoring before and after the appointment of an ASN were compared. In 112 patients on dronedarone in the year prior to the appointment of an ASN, only 478 of the 1,275 (37%) required tests were actually done. With the ASN, 382 of 422 (92%) tests in 53 patients were performed. This was significantly better (p<0.001). Dronedarone was more likely to be stopped due to contraindications (p<0.017) prior to the appointment of ASN, but afterwards was more likely to be stopped due to side effects (p<0.001).

The ASN significantly improved adherence to EMA-mandated monitoring in patients on dronedarone. Involvement of an ASN had no overall impact on the likelihood of dronedarone being stopped. Patients were more likely to have the drug stopped due to side effects, and were less likely to stop for safety reasons. ASN care is superior to conventional follow-up, and is the gold standard for patients treated with dronedarone.

Percutaneous coronary intervention (PCI) has established itself as an effective alternative to coronary artery bypass graft surgery (CABG) in appropriate patients. However, the proportion of patients that undergo CABG and/or valve surgery (VS) following PCI in the short and long term is currently unknown.

We conducted a single-centre, retrospective study examining the indications and number of patients requiring CABG and or VS following successful PCI between 2009 and 2012. The surgical procedure was categorised as early (referred within <1 month of the index PCI), mid-term (referred 1–12 months after index PCI) and remote (referred >1 year and up to four years following the index PCI). 

During each three-year period (2008–2010, 2009–2011), 5,244 PCIs were performed at our centre. The total number of patients referred for cardiac surgery post-PCI was 63 (1.2%). The number of patients referred for early, mid-term and remote cardiac surgery was 21 (0.4%), 14 (0.26%) and 28 (0.53%), respectively. Within the early group, eight patients had extensive three-vessel disease stabilised with emergency/urgent PCI to allow subsequent CABG, while 10 patients had failed PCI to a chronic total occlusion. In the mid-term group, the main reason for surgery was rapid progression in coronary disease. In the remote group, the majority of patients underwent surgery for progression of valve disease. 

Our data suggest that the number of patients requiring CABG and/or VS following PCI is small, and the indications differ with time following the index PCI. We hope that these results will provide reassurance and interest to our interventional colleagues. 

A 53-year-old woman presented with history of exertional chest pain. A coronary angiogram subsequently showed an unusual and rare coronary artery anatomy: all of her coronary arteries originate from the right coronary cusp, with separate ostia. In addition, the left anterior descending (LAD) artery was hypoplastic resulting in ischaemia.

Identification of those at low risk of developing heart failure (HF) after acute coronary syndrome (ACS) would aid clinical management, but it is unclear whether N-terminal pro-brain natriuretic peptide (NT-proBNP) adds to the predictive accuracy of troponin. There were 229 subjects recruited into a prospective cohort study. Subjects were assessed for acute heart failure (AHF) prior to discharge and for readmission within 30 days of their ACS event (cohorts A+B). Cohort A (n=116) were further assessed for readmission within 12 months. Troponin I (TnI) and NT-proBNP levels were measured at ACS onset and at 6–12 hours. Readmissions were identified using electronic records. In total, 23.6% of subjects developed AHF during the index admission: 10.0% were readmitted within 30 days of admission; 17.2% within three months; 26.7% within six months and 36.2% within 12 months. At presentation, NT-proBNP, but not TnI, was significantly elevated among subjects who developed AHF compared with non-AHF subjects. Compared with non-readmitted subjects, readmission within 30 days was associated with significantly lower baseline NT-proBNP, and readmission after 30 days with higher baseline NT-proBNP. For all periods, TnI level was lower among readmitted compared with non-readmitted subjects. In conclusion, NT-proBNP has a potential role for rule out of those at low risk of AHF development and readmission. 

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.