Clinical articles

The authors describe a case of hyperkalaemia in a patient receiving trimethoprim.

The term pharmaceutical salt is used to refer to an ionisable drug that has been combined with a counter-ion to form a neutral complex. Converting a drug into a salt through this process can increase its chemical stability, render the complex easier to administer and allow manipulation of the agent’s pharmacokinetic profile. Salt selection is now a common standard operation performed with small ionisable molecules during drug development, and in many cases the drug salts display preferential properties as compared with the parent molecule. As a consequence, there has been a rapid increase in the number of drugs produced in salt form, so that today almost half of the clinically used drugs are salts. This, combined with the increase in generic drug production, means that many drugs are now produced in more than one salt form. In almost all cases where multiple drug salts of the same agent exist, they have been marketed as therapeutically equivalent and clinicians often treat the different salt forms identically. However, in many cases this may not be justified. This review describes why many pharmaceutical salts are, in fact, not chemically equivalent, and discusses whether such chemical differences may translate into differences in therapeutic effectiveness. It will also explore, with examples, what the clinical cardiologist should consider when prescribing such agents for their patients.

Peripheral arterial disease (PAD) is a condition that is frequently underdiagnosed and often the subject of suboptimal care. It can present with rest pain or gangrene (critical ischaemia), but this is not common. Intermittent claudication (IC), leg pain on walking, is its most common manifestation. Leg pain on walking is a presentation commonly seen in general practice, and has several potential causes other than PAD. IC has been shown to affect 4.5% of subjects between the ages of 45 and 65 years and is a marker for increased cardiovascular risk.1 In respect of the leg itself, IC is a relatively benign condition with most patients improving or stabilising and fewer than 5% progressing to major amputation. However, patients with IC are at increased risk of death, especially due to vascular events in the coronary and cerebral territories.2 PAD is caused by the occlusion or narrowing of large peripheral arteries, usually from atherosclerosis, and, as such, it shares all the major risk factors that can lead to myocardial infarction (MI) or stroke. Most patients with PAD will also have disease (either symptomatic or asymptomatic) in their coronary and cerebral circulation, and MI and stroke are common causes of death in patients with PAD. Vigilance for the condition will provide opportunities to reduce cardiovascular risk in a group who are high risk. Accurate diagnosis and assessment will reveal those who would most benefit from specialist intervention.

The multi-disciplinary approach provides a forum for peer review of angiographic data. We aimed to examine the outcomes of our multi-disciplinary team (MDT) meetings in a two-year follow-up study. A total of 191 patients were studied and mainly divided into groups offering conservative therapy, percutaneous coronary intervention (PCI) or coronary artery bypass surgery (CABG). CABG was offered to 60% of patients with left main stem disease, 45% with proximal left anterior descending artery lesions and 59% with triple-vessel disease. PCI was offered to 40% of patients with single-vessel disease. One death was observed in the PCI group at two years, substantially lower than deaths in other groups. Overall mortality at two years was 6.4%. PCI conferred a significantly higher need for repeat revascularisation compared with surgery (odds ratio 5.71, p=0.005). Our results resonate with outcomes of published trial data comparing CABG and PCI.

The treatment of raised cholesterol has advanced significantly in the last 25 years: fibrates, statins, bile acid sequestrants, ezetimibe, and more. In October 2007, colesevelam hydrochloride was launched into the UK market. This article reviews where this product fits into everyday clinical practice, in which patients it is best suited, and discusses practical issues in the everyday use of this reformulated bile acid sequestrant.

We undertook a seven-year in-depth review of all reported obituaries of medical practitioners in the BMJ to assess the age and disease distribution of mortality of medical practitioners in order to identify relationships between mortality and discipline, ethnicity and other demographic factors. In total, 3,342 obituaries reported in the BMJ from January 1997 to December 2004 were reviewed.

The majority of obituaries were of male doctors. Doctors who qualified in the developed world appeared to live longer (mean age at death of 78 years) than those who qualified in Asia (mean age at death of 70 years). White-European doctors lived significantly longer than doctors from other ethnic groups. There was no significant difference in longevity between doctors working in the primary care sector and those in the secondary care sector. An eighth (12.5%) of doctors died between the ages of 60 and 70 years and, of these, nearly half died between the ages of 61 and 65 years. There were significantly more suicides and accidental deaths in Accident and Emergency (A&E) doctors compared with other specialties.

In conclusion, cardiologists are not immortal and need to retire, as do their colleagues in other specialties. Retirement at ages of 65 years or above would disadvantage nearly one in six medical practitioners. Those likely to be most disadvantaged by a mandatory rise in any retirement age, in terms of reaping the benefits of their pension contributions, are those of a non white-European ethnicity.

Contrast enhancement cardiac magnetic resonance (CE-CMR) is a new tool for the assessment of myocardial viability. The technique uses an inversion-recovery prepared T1-weighted gradient-echo pulse sequence after the intravenous administration of a gadolinium-chelate (Gd). Gd diffuses into the interstitium but not the myocardial cells, hence, infarcted myocardium has an increased concentration of Gd resulting in hyper-enhancement. CE-CMR was validated in animal models,1 and human studies confirmed that the technique identifies the presence and extent of myocardial infarction in addition to predicting reversible myocardial dysfunction in patients undergoing revascularisation.2-4 The CE-CMR images consist of short-axis and long-axis slices of the left ventricle (LV) and are analysed based on the 17-segment model of the LV. The non-viable myocardial tissue is hyper-enhanced and white. The degree of the transmurality of the contrast enhancement (CE) in each segment is scored, based on outcome data, where <25% transmurality is highly likely to recover function, 25–50% transmurality is potentially viable with 50% chance of recovering function, and >50% transmurality is unlikely to be viable.2-4 We present two cases, which illustrate the usefulness of this technique in detecting viable myocardium and facilitating the clinical decision-making process for revascularisation.

Within a prospective observational study we investigated whether patients undergoing coronary angiograms present a more accessible and significant cohort for abodominal aortic aneurysm (AAA) screening. With local research ethics committee approval, over 36 days, 106 consecutive patients consented to and underwent a five to eight minute aortic scan, using a portable ultrasound unit, during the recovery period after angiography. Anteroposterior and transverse, suprarenal and maximal infrarenal aortic diameters were measured. The ultrasonographer was blinded to the angiogram results.

Of 104/106 successful scans 73 were conducted in male patients and 31 in female patients. Six males and 11 females had normal coronary arteries and no aneurysms. From 87 patients with ischaemic heart disease (IHD), eight males had aneurysms ≥3 cm diameter. Mean diameter was 4.2 cm (standard deviation [SD] 1.96, range 3–8.7 cm). Two additional males and two females had focal aortic dilatations of twice suprarenal aortic diameter yielding 14.9% and 10% incidence of aneurysmal change in scanned males and females with IHD. Average ages for patients with IHD were 62.2 years (SD 10.7, range 41–81 years) for males and 68.0 years (SD 10.6, range 47–88 years) for females. Average age for males with aneurysmal change was 68.8 years (SD 11.5, range 45–79 years).

Results from this pilot study suggest that screening patients with IHD has a significantly higher yield than expected by the National Programme. These high-risk patients would benefit more than the general population from early detection and cardiovascular optimisation possibly with earlier AAA repair. Further expansion of the study would allow corroboration and qualification of these findings.

This article is an enlightened approach to reducing strokes in patients with atrial fibrillation (AF). It discusses some freely available software called ‘The Auricle’ and shows how this can easily be used to calculate the annual risk of a stroke. GPs and patients are supported in the careful decision about anticoagulation. To this end the programme has an e-consultation option to ask the opinion of a local cardiologist with the flexibility to attach an electrocardiogram (ECG), echo or clinic letter, if desired. All the details and the cardiologist’s opinion can be electronically filed in the patient’s notes to confirm that the pros and cons of warfarin were fully debated.

A 29-year-old man was admitted with new onset atrial fibrillation (figure 1).