Cardiovascular diseases

The rates of RHD are among the highest in the world, particularly in girls and young women

Kimberly Davis · Bo Remenyi · Anthony DK Draper · Januario Dos Santos · Noel Bayley · Elizabeth Paratz · Benjamin Reeves · Alan Appelbe · Andrew Cochrane · Timothy D Johnson · Laura M Korte · Ivonia M Do Rosario · Inez T Da Silva Almeida · Kathryn V Roberts · Jonathan R Carapetis · Joshua R Francis

To the Editor:We thank Rakhra and colleagues,1 whose report highlighted a group of potential donors yet to be fully exploited for organ transplantation. While this untapped potential appears to largely affect kidney and lung donor pools, we must not exclude the effect that relaxing donor suitability criteria may have on the heart. While not largely emphasised, the data collected for the heart are compelling, particularly for an organ so susceptible to ischaemic injury. Similar to the kidney and lungs, the data show that when including ideal and expanded criteria, potential donors more than doubled the number of donor hearts available for heart transplantation.1 This is an important finding, particularly if the authors have conservatively underestimated the actual potential for organ donation. In Australia, donation after circulatory death (DCD) kidney and lung donors comprise 25–30% of the total donor pool for these organs.2,3 Since 2014, the number of national and international hospitals now investigating DCD heart donation has increased, and we anticipate that DCD heart transplantation will follow the same trend as DCD lung and kidney transplant over time. The Critical Care Research Group at the Prince Charles Hospital has developed a clinically relevant 24-hour ovine model of brain stem death,4 and these donor hearts are being used to transplant into recipient animals. Transplant clinicians and researchers from the Prince Charles Hospital, the Alfred Hospital and St Vincent’s Hospital will collaboratively employ an ex vivo hypothermic perfusion system, capable of safely storing animal hearts up to 24 hours,5 together with novel cardioprotective therapeutics to increase the allowable ischaemic times for donor hearts without impairing graft function. This technology will hopefully extend to DCD donors in the future, which are currently only preserved using a warm blood perfusion system. By relaxing donor heart suitability criteria, and using novel machine perfusion technology to increase the storage time of the donor heart,5 thus eliminating time and travel distance constraints in Australia, the donor heart pool could be greatly increased. While the numbers may ultimately be modest, the positive effect on those recipients would be substantial.

Louise E See Hoe · David McGiffin · John F Fraser

To the Editor: Cullen and colleagues are to be congratulated on their most recent contribution to the assessment of emergency department patients presenting with possible acute coronary syndrome.1 The ability to safely reduce length of stay for a larger proportion of patients compared with the ADAPT study, pending external validation, is promising.1 The timing of the article also presents an invaluable opportunity to remind all clinicians that despite the progressive improvements in accelerated diagnostic pathways for chest pain, not all chest pain is cardiac. Accelerated diagnostic pathways, when used incorrectly, run the risk of introducing cognitive dispositions to respond such as availability bias (where a clinician may choose a diagnosis that is more familiar, such as acute coronary syndrome), omission bias (doing something easy and omitting something hard, such as ordering serial troponins instead of a computed tomography aortogram) and Sutton’s slip (settling on the most obvious interpretation of the problem).2 The potential for error is further compounded by error-producing conditions inherent in busy emergency departments, such as overcrowding, narrow time windows for assessment, surge phenomena and multiple transitions of care (eg, movement to short stay).3 It is pleasing to see that additional features were utilised in stratifying patients compared with previous accelerated diagnostic pathways.1 High-risk features such as prolonged duration and recurrence of chest pain as well as syncope may also be present in aortic dissection.4 It is possible that a patient presenting with an aortic dissection could be deemed low risk with criteria such as those in the ADAPT accelerated diagnostic pathway.5 Troponin levels do not provide a safeguard, as evidenced in a previous case where a 75-year-old woman was discharged home after two normal troponin test results only to die later the same day from progression of a type A aortic dissection.4 Aortic dissection is a lethal cardiovascular emergency that boasts significant morbidity and mortality.4 It has been astutely described as the “subarachnoid haemorrhage of chest pain”.4 Although it is rare and sometimes difficult to diagnose compared with acute coronary syndrome, clinicians are urged to include aortic dissection in their initial assessment of chest pain before implementing an accelerated diagnostic pathway.

Joe-Anthony Rotella

To the Editor:I thank Kritharides and colleagues1 for their review Cardiovascular disease in patients with schizophrenia. I agree with them and support their work, which seeks to improve the physical health of patients living in the community with a chronic mental illness such as schizophrenia, through an innovative, coordinated and multidisciplinary model of care. Clozapine side effects, including risks of myocarditis and cardiomyopathy, hypercholesterolaemia and weight gain, reduce years of life and require medical attention. But the management is not always straightforward. One challenge is patient compliance with often demanding allied health therapies. How do we keep our patients motivated to continue with prescribed regular exercise most days of the week? How do we encourage compliance with a weight-reducing, low salt, low glycaemic index diet? Multidisciplinary primary care and specialist teams may consider a rehabilitation approach to complement the model of care. Two essential elements are goal setting and measurement of function.2 Some patients will be motivated by their personal goals (eg, getting back to weighing 80 kg or playing a game of table tennis) and other patients will appreciate their gain in terms of function (eg, walking up the stairs without a rest or shopping for groceries independently) more so than in terms of presented data (eg, cholesterol levels or absolute cardiovascular risk reduction). For motivating patients with schizophrenia and significant cardiovascular risk, a rehabilitation approach may be worth a try.

David Skalicky