Dear Editor,

We read with great interest the French perspective on prophylaxis of infective endocarditis by Danchin and colleagues which seem considered and balanced.[1] They focus on the importance of ensuring prophylaxis for high -risk patients undergoing high-risk procedures. They also emphasise the importance of “the physician’s evaluation of the individual risk in a given patient”. They espouse this view because of the very limited evidence available on either risk from invasive procedures or the effectiveness of antibiotic prophylaxis. This latter point is echoed in another article in this month’s Heart by Niwa and colleagues. They show that in over a quarter of cases in their cohort where conditions and procedures associated with an endocarditis risk could be identified, prophylaxis was given but actually failed to prevent endocarditis.[2]

These international observations on the problems of endocarditis prophylaxis contrast strongly with the approach taken by the British Cardiac Society (BCS) which recommends widespread use of broad spectrum antibiotics for any person with a clinically detectable structural heart lesion who is about to undergo an invasive procedure.[3] The manifest risks of widespread antibiotic use such as increased antibiotic resistance, antibiotic-associated colitis (a potentially fatal condition), penicillin anaphylaxis, etc., have been dismissed as “fallacious and feeble” by the authors of the BCS guidelines. However the risks of antibiotic resistance are emphasised in the French guidelines.[1,4]

These two articles in this month’s issue of Heart affirm our deep concerns that are widely shared by British, European, North American, and Australian gastroenterologists, (Dr. DF Levine and others, personal communications) that the new BCS guidelines are overly aggressive. The BCS guidelines are predominantly based on Level IV (consensus and expert opinion) evidence, which are universally acknowledged as the least robust type of evidence on which to base management decisions.

We strongly support the proposition of the Société de pathologie Infectieuse de Langue Française and the Société Française de Cardiologie at their end of the article, which challenges the cardiological community at large to provide a stronger evidence base for future guidelines. It will be necessary to quantify both the absolute risk of endocarditis for invasive procedures, the likely effectiveness of prophylaxis, and the possible harms of the strategy proposed. Only then would any guidelines that emerged be clinically useful, and therefore widely embraced and rigorously applied to ensure effective prophylaxis is given for those highest risk patients whom it may benefit.

References

1. Danchin N, Duval X and Leport C. Prophylaxis of infective endocarditis: French recommendation 2002. Heart 2005;91:715-718.

2. Niwa K, Nakazawa M, Yoshinaga M and Terai M. Infective endocarditis in congential heart disease: Japanese national collaboration survey. Heart 2005;91:795-800.

3. Ramsdale DR, Turner-stokes L; Advisory group of the British Cardiac Society clinical practice committee; RCP clinical effectiveness and evaluation unit. Prophylaxis and treatment of endocarditis in adults; A concise guide. Clin Med 2004;4:545-50.

4. Ramsdale DR, Palmer ND. Prophylaxis and treatment of endocarditis in adults; A concise guide (author reply). Clin Med 2005;5:183-184.

Dear Editor,

We thank Dr Kelion for his helpful comments regarding our recent review on stress echocardiography in Heart [1]. We entirely agree with Dr Kelion that both British Society of Echocardiography and British Nuclear Cardiac Society need to raise awareness of the utility of functional tests for the assessment of coronary artery disease and not squabble about which technique is superior. Given the fact that both stress echocardiography and SPECT imaging have similar diagnostic accuracy, either technique may be used to perform functional testing.

The decision to proceed to echocardiography or SPECT will depend on local availability and local expertise. When both techniques are accessible with equal availability of expertise, the choice of test will largely depend on the shorter waiting time of the tests. It is time the National Institute of Excellence (NICE) incorporated stress echocardiography alongside SPECT for the assessment of CAD, not least, because the current guidelines by American College of Cardiology (ACC) and American Heart Association recommend use of either imaging technique for the assessment of CAD.

Yours sincerely,

R Senior
M Monaghan
H Becher
J Mayet
P Nihoyannopoulos

References

1. Senior R, Monaghan M, Becher H, Mayet J, Nihoyannopoulos P. Stress echocardiography for the diagnosis and risk stratification of patients with supected or known coronary artery disease: a critical appraisal. Heart 2005; 91: 427-436.

Dear Editor,

It is well known the relationship between coronary anomalies and other congenital cardiac abnormalities [1-2]. Indeed, association between atrial septal defect and coronary anomalies has been previously described and in this situation compression of the anomalous coronary artery can occur when septal defects is percutaneously closed [3-4]. We suggest that a transesophageal ecocardiogram should be done when percutaneous closure is planned in patients with an atrial septal defect. It would be useful to identify the ostium and initial course of both coronary arteries, and will help to avoid possible additional procedure complications.

References

1. Topaz O, DeMarchena EJ, Perin E et al. Anomalous coronary arteries: angiographic findings in 80 patients. Int J Cardiol 1992;34:129-38.

2. Barriales-Villa R, Morís C, López-Muñiz A et al. Anomalías congénitas de las arterias coronarias del adulto descritas en 31 años de estudios coronariográficos en el Principado de Asturias: principales características angiográficas y clínicas. Rev Esp Cardiol 2001;54:269-281.

3. Maki F, Ohtsuka T, Suzuki M et al. Myocardial ischemia induced by anomalous aortic origin of the right coronary artery in a patient with atrial septal defect. Jpn Heart J 2001;42:371-6.

4. Casolo G, Gensini GF, Santoro G et al. Anomalous origin of the circumflex artery and patent foramen ovale: a rare cause of myocardial ischaemia after percutaneous closure of the defect. Heart 2003;89:e23.

Dear Editor,

The recent review of stress echocardiography in Heart is a good overview of a technique which has clearly come of age [1]. However it really is time that the echo community stopped being so defensive about the alternative technique of myocardial perfusion scintigraphy (MPS).

In November 2003 the National Institute for Clinical Excellence (NICE) published the positive results of its Technology Appraisal 73, entitled “Myocardial perfusion scintigraphy for the diagnosis and management of angina and myocardial infarction” [2]. The value of myocardial perfusion scintigraphy (MPS) as a mature diagnostic and prognostic investigation was recognised, and it was estimated that an approximately four-fold increase in MPS activity in the UK might be appropriate. The Appraisal has aroused much controversy, particularly from proponents of stress echocardiography, who feel that NICE should have considered the full range of non-invasive tests available for patients with known or suspected coronary disease. This grievance has spilled over into the review cited above, and the authors have erred in making ill-informed negative comments about MPS.

The stock objections to MPS raised by the authors are that “its widespread use is limited by cost, radiation, and relative lack of availability” [1]. It is time that these myths were dispelled, beginning with the cost argument. A small-field-of-view dedicated cardiac gamma camera now costs the same as a decent echo machine, and both require one member of staff for scanning and a similar sized room. The facilities required for stress in terms of space, hardware, and staff (usually two in the room) are independent of the imaging modality being used. The cost of consumables is roughly the same for both imaging modalities, and is dominated by the price of the radiopharmaceutical (MPS) or echo contrast agent (stress echo). One important advantage of MPS is that, compared with other modalities, the imaging side of MPS is fixed and automated so that the requirement for “hands-on” consultant time (an expensive resource in the NHS) is limited to reporting. Ultimately, any difference in the cost per patient between modalities is largely a function of patient throughput, which can be extremely efficient using MPS with a dedicated cardiac gamma camera (more than 2000 patients per year).

The radiation argument is specious. The effective dose equivalent from a MPS study performed using a modern technetium-99m-based tracer is 10mSv, which is similar to that from a coronary angiogram or CT scan [3]. In a healthy 40 year old male, after a 10 year latency period, this confers an increased risk of developing cancer of 1 in 3000, compared with a background lifetime risk of 1 in 6. Radiation exposure is (rightly in our opinion) not a consideration when deciding, for example, whether a patient should have an abdominal CT scan instead of an abdominal ultrasound, or prior to coronary angiography, and so the focus on nuclear medicine procedures in this regard is difficult to understand.

The argument that MPS in inherently more difficult to set up and therefore less available than other imaging modalities is demonstrably false internationally. In a recent European survey of 3779 patients presenting to a cardiologist with angina, a stress-based imaging test was performed in 18% of cases [4]. This test was MPS in 95% of patients in northern Europe (including the UK), 91% in the Mediterranean, 84% in western Europe, and 66% in central Europe: clearly our European colleagues are unaware that MPS is more difficult to set up than its alternatives. The only real difficulty, particularly in the UK, is the tight regulatory framework which governs nuclear medicine procedures. However, the majority of reasonably sized district general hospitals already have a nuclear medicine department, and so the framework is almost always already in place.

The real reason that MPS has been slow to be adopted in the UK is “political”. MPS, in contrast to other cardiac imaging techniques, is usually performed by radiologists and nuclear physicians rather than cardiologists. This makes alternative cardiologist-led techniques such as stress echocardiography more attractive when a functional imaging test is required. The answer to this is not to disparage MPS itself, but to motivate cardiologists to become more involved. This has occurred in the USA, where more than 20,000 MPS studies per million population per year are currently performed (compared with 5000 across Europe and just over 1000 in the UK).

In reality, The UK is so far behind the rest of the developed World in terms of noninvasive imaging for coronary disease that squabbles between the proponents of the various imaging modalities are an unhelpful distraction. The clinical information provided by all of the stress-based imaging tests, when performed by appropriately skilled staff, is more-or-less equivalent. It matters little how many of the 4000 patients pmp per year identified by NICE undergo stress echocardiography rather than MPS: if the wider cardiology community accepts that functional imaging is a valuable exercise, there will be more than enough work for all of us.

References

[1] Senior R, Monaghan M, Becher H, Mayet J, Nihoyannopoulos P. Stress echocardiography for the diagnosis and risk stratification of patients with supected or known coronary artery disease: a critical appraisal. Heart 2005; 91: 427-436.

[2] http://www.nice.org.uk/TA073guidance

[3] Picano E. Informed consent and communication of risk from radiological and nuclear medicine examinations: how to escape from a communication inferno. BMJ 329: 849-51.

[4] Daly CA, Clemens F, Lopez Sendon JL, Tavazzi L, Boersma E, Danchin N, et al. The clinical characteristics and investigations planned in patients with stable angina presenting to cardiologists in Europe: from the Euro Heart Survey of Stable Angina. Eur Heart J 2005 (E-published ahead of print).