An imaginative programme addressing head-on challenging debates within the valve community was presented at the recent British Heart Valve Society Annual Meeting. Held at St Bartholomew’s Hospital, London, on 14th October 2016, the meeting attracted cardiologists, cardiologists in training, cardiac physiologists, cardiothoracic surgeons and microbiologists. Margaret Loudon reports its highlights.
A pathologist’s eye view of valve disease started the day with a presentation from Professor Kim Survana (Consultant Pathologist, Sheffield Teaching Hospitals NHS Trust). Covering the range from normality, to degenerative, calcific, rheumatic, congenital and infective pathology, slides of macroscopic and microscopic specimens brought to life what cardiologists see and hear in their daily practice, or as Professor John Chambers (Consultant Cardiologist, St Thomas’s Hospital, London) coined: “the reality of shadows”.
Reviewing culture negative endocarditis, Dr John Klein (Consultant Microbiologist, Guy’s and St Thomas’s NHS Foundation Trust, London) offered a personal view of managing this most challenging pathology. He reminded us of the importance of blood culture, serology, valve PCR and histology of excised specimens. The utility of these was illustrated in two thought-provoking cases, where the key-take home message reminded us of the importance of the multidisciplinary team.
Moving into the realm beyond three blood cultures was described by Dr Jonathon Sandoe (Associate Clinical Professor of Microbiology and Honorary Consultant Microbiologist, The Leeds Teaching Hospital NHS Trust. After reviewing advanced microbiology and ‘the basics’, he said the biggest determinant of the sensitivity and specificity of the key investigation (blood cultures) lies with technique of the sampler. Moving beyond simple cultures are newer developments. MALDI-TOF-MS (matrix associated laser desorption/ionization time of flight mass spectroscopy) allows quicker identification of culprit organisms, often within hours. PCR of blood cannot yet be recommended but broad range 16S rRNA gene PCR of excised valve tissue is helpful, robust and provides real added value. Finally, he gave a sobering reminder of the real and current problem of antibiotic resistance, especially in pseudomonas species.
Deciding the choice between early or late surgery in infective endocarditis, was tackled by Mr Neil Roberts (Consultant Cardiothoracic Surgeon, Barts Health NHS Trust, London). Practice has shifted to favour early surgery, while the balance of operating on septic patients or infected tissue was acknowledged. Evidence behind the 2009 European Society of Cardiology (ESC) guidelines on this topic was explored. The conclusion was adherence with the ESC is important, while maintaining individual flexibility within a multidisciplinary team.
Medico-legal issues
The next and perhaps most widely anticipated session ‘Antibiotic prophylaxis in the dock’ featured Mr Mark Trafford (QC, London) presenting the background and legal precedents of informed consent. The legal viewpoint of important issues should include the following:
- Full notes available to the consenter
- A discussion of the alternatives
- Adequate time for discussion
- Tailored to individual patient and case
- Two-way dialogue
- Avoid focus on percentages of risk
- Common and catastrophic outcomes
- Ensure full understanding
- A leaflet is not enough.
It was acknowledged that many medics feel too much information does not always assist a patient to make decisions but the majority legal opinion favours very full information.
Dr Chris Primus (Specialist Registrar in Cardiology, Barts Health NHS Trust, London) presented a case of prosthetic valve endocarditis for legal and expert witness scrutiny. In particular, the issues of whether antibiotic prophylaxis for a dental procedure should have been given were debated. Dr Bernard Prendergast (Consultant Cardiologist, Guy’s and St Thomas’s NHS Foundation Trust, London) acted as expert witness and highlighted the recent change in wording in the new 2016 National Institute for Health and Care Excellence (NICE) endocarditis prophylaxis guidelines,2 which following patient campaign, now state endocarditis prophylaxis should not be routinely prescribed.
Finally, we learned the sobering reality that inpatient mortality from infective endocarditis remains at 15–20%, with a one-year mortality of 30–40%. The risk is hugely increased in prosthetic valve infective endocarditis, although 42% of those who develop infective endocarditis do not know they are at risk.
The main points that arose from the discussion, was that cardiologists may have taken their eye off the ball regarding infective endocarditis prophylaxis and this area was a perfect recipe for medico-legal action. The British Heart Valve Society expressed a strong desire to see collaborative work with interested parties – including microbiologists and dentists – to produce a UK consensus document to try to address “uncertainty in a vacuum of responsibility”.
Young investigators award
The next session showcased impressive research from London, Oxford and Rome with technical innovation being presented by the next generation of cardiovascular scientists. The synergy of engineering and advanced imaging won the day with the Young Investigator award going to Benyamin Rahmani (Bioengineer, University College London) for his description of the fluid dynamic research behind the production of a new transcatheter heart valve concept, the Triskele valve, which is expanding the horizons of transcatheter aortic valve implantation (TAVI). A limitation to manufacture of TAVI valves is the length of time to produce them – a process that takes more than 18 hours as they are hand stitched and then a 30–40% quality control turn down. The Triskele valve has polymer leaflets and is robotically manufactured, offering the possibility of faster, cheaper and more durable valves when tested against market leaders.
Topical debates
The final session addressed head-on debates around timing of valve surgery, valve disease in non-cardiac surgery and the role of balloon aortic valvotomy.
Dr Sanjeev Bhattacharyya (Consultant Cardiologist, Barts Health NHS Trust and University College London Hospital) discussed watchful waiting versus early surgery in asymptomatic mitral valve prolapse with severe mitral regurgitation. Key evidence that helped form the ESC3 and American Heart Association (AHA)/American College of Cardiology (ACC) guidelines4 was discussed with case studies to demonstrate the patient flow pathways. The need for high quality randomised controlled trials with robust long-term data was highlighted.
Dr Mark Dweck (Senior Lecturer and Consultant Cardiologist, the Edinburgh Heart Centre) presented the data for watchful waiting versus early surgery in asymptomatic stenosis and the 2012 ESC guidelines.2 The notion of aortic stenosis as a disease of the myocardium as well as the valve was discussed and an update on current UK randomised controlled trials into early surgery was given.
One of the many difficult decisions in severe aortic stenosis is undergoing non-cardiac surgery. Professor John Chambers highlighted the lack of randomised, controlled clinical trial data and our reliance on registry data. Data from the Mayo Clinic, USA, (published in 2014) suggest no difference in outcome in emergency non-cardiac surgery in those with and without severe aortic stenosis. A symptomatic patient, however, has a much higher risk. If there is time to plan, assessment of exercise capacity in expert hands may be useful. Learning points were:
- asymptomatic aortic stenosis has an acceptable risk in non-cardiac surgery
- risks increase with symptoms, impaired left ventricular function, coronary disease, severe mitral regurgitation
- inappropriate aortic intervention delays non-cardiac surgery
- all significant aortic stenosis needs special precautions around the time of surgery.
The final talk of the day was given by Dr Simon Kennon (Consultant Cardiologist, Barts NHS Health Trust, London) and covered balloon aortic valvotomy (BAV), asking whether it was a useful tool versus a waste of time. Practice varies widely and, once again, evidence is registry based. The 2014 AHA/ACC guidance4 suggests use of BAV as a bridge to TAVI or aortic valve replacement (AVR) only. The ESC suggests it may be useful as a bridge to TAVI/AVR, or for urgent non-cardiac surgery in unstable patients, and as a palliative tool to relieve intractable heart failure. The outcomes can be variable and unpredictable and operators and patients must be aware of this. The discussion that followed accepted a role for facilitating urgent non-cardiac surgery and a likely culture shift towards TAVI as the primary option in future.
Further information
Further information about the British Heart Valve Society can be found at: https://www.bhvs.org.uk. The British Heart Valve Society is officially associated with the British Cardiac Society and the Society for Cardiovascular Surgery of Great Britain and Ireland. It has four main types of activity:
- Education and training
- Research
- Articles
- Working groups.
Margaret Loudon
ST7, Oxford University NHS Foundation Trust
References
1. Habib G, Hoen B, Tornos P et al. Guidelines on the prevention, diagnosis, and treatment of infective endocarditis (new version 2009): The Task Force on the Prevention, Diagnosis, and Treatment of Infective Endocarditis of the European Society of Cardiology. Eur Heart J 2009;30:2369–13. https://doi.org/10.1093/eurheartj/ehp285
2. National Institute for Health and Clinical Excellence. Clinical guideline [CG64]. Prophylaxis against infective endocarditis: antimicrobial prophylaxis against infective endocarditis in adults and children undergoing interventional procedures. London: NICE, 2016. https://www.nice.org.uk/guidance/cg64 (last accessed 12th April 2017)
3. Vahanian A, Alfieri O, Andreotti F et al. European Society of Cardiology (ESC) Guidelines on the management of patients with valvular heart disease (version 2012). Eur Heart J 2012;33:2451–96. https://doi.org/10.1093/eurheartj/ehs109
4. Nishimura RA, Otto CM, Bonow RW et al. 2014 American Heart Association/American College of Cardiology (AHA/ACC) guideline for the management of patients with valvular heart disease. Circulation 2014;129: 2440–92. https://doi.org/10.1161/CIR.0000000000000029
