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Introduction
The population prevalence of moderate or severe valve disease in industrialised countries is as high as 13% in those aged 75 years or older.1 Undetected valve disease leads to premature death1 but valve surgery, when indicated, can prolong life.2 Access to medical care in industrialised countries is usually good, but limitations exist3 and better ways of organising care are needed.4
A working group was therefore convened by the British Heart Valve Society with representatives of all interested national bodies and a panel of invited international commentators. The aim was to produce recommendations to improve the detection, conservative management and interventional treatment of valve disease. This paper focusses on conservative management and proposes recommendations for overcoming limitations in care by means of a specialist valve clinic.
Limitations in current services
The initial management of patients with valve disease is usually conservative and meticulous follow-up is then vital. However, accepted management guidelines are not followed adequately.5–7 Furthermore, the application of accepted guidelines requires specialist experience especially in determining whether a patient is genuinely asymptomatic. Most patients with valve disease are still cared for by general cardiologists or general physicians who may be less skilled than a valve disease specialist in making a diagnostic formulation. Furthermore, it is likely that advances in practice are more slowly assimilated by a generalist than by a cardiologist who undertakes specialist continuing education.
As a result, patients are often referred for surgery too late. In the EuroHeart Survey,6 approximately one half of patients were in New York Heart Association class III or IV at the time of valve surgery. At least one third of elderly patients with severe aortic stenosis are not referred for surgery at all even when clinically indicated.8 Developing a percutaneous valve programme leads to increased rates of conventional surgery suggesting the previous existence of clinically inappropriate perceptual barriers to referral.
Patients with normally functioning replacement valves should be assessed clinically every year,2 but may not require regular echocardiography. In practice, these patients are often discharged and may not receive further follow-up.9
Value of a specialist valve clinic
Multidisciplinary clinics are now widely used10 in cardiovascular disease as well as chronic pain, diabetes and respiratory disease. There is evidence that they improve the application of guidelines and the modification of risk factors to improve outcomes.10 Similarly, we propose that the initial assessment and subsequent surveillance of valve disease should occur in specialist valve clinics.
Surveillance in a specialist clinic improves adherence to international guidelines and reduces unnecessary echocardiograms.7 A number of centres in the UK have shown that surveillance can safely be devolved to senior sonographers or nurses working within a tight protocol and with supervision from a cardiologist.9 Delegating surveillance in this way allows the cardiologist to spend more time with patients for whom clinical decisions are required. However some 10–15% of cases require cardiological assessment, and a further 20% of patients within a nurse-led clinic9 may require medical advice to guide the nurse at the index visit. Ideally, therefore, a cardiologist should always be present, but if not there should be a clear action plan for dealing with urgent or non-urgent enquiries. This arrangement in which surveillance is devolved to a sonographer or nurse is applicable within the UK, but may not be appropriate in other healthcare systems.
There is no proof from randomised trials that specialist clinics are better or more cost-effective than conventional care, but there is much corroborative evidence. For example, patients with severe degenerative mitral regurgitation have a higher mortality than those with moderate regurgitation, but survival is excellent if they are managed in a valve clinic11 with expert echocardiography and meticulous follow-up. A group in Vienna (Zilbersac, unpublished data) has shown that patients with severe aortic stenosis have symptoms detected earlier and at a lesser severity within a valve clinic compared with those referred from other clinics.
The clinic should extend its influence to coordinate a specialist valve service including inpatient care, links with the community and with other hospitals and the dissemination of information about valve disease. In designing a specialist valve clinic and service various components need to be addressed.
Aim of specialist clinic and valve service
The medical aims of a valve clinic are to: evaluate patients correctly; monitor valve disease at appropriate intervals; determine the correct timing of surgery; determine which type of surgery is needed; refer to the appropriate surgeon; assess results after surgery; and importantly educate and inform patients about valve disease both before and after surgery.
The wider aims of a valve service may include to: supervise inpatient care of valve disease; train general cardiologists and other physicians in specialist valve disease; keep colleagues up to date with developments in valve disease; write protocols to disseminate modern practice; help maintain valve teams, for example, for mitral repair, transcatheter techniques or endocarditis.
The organisational aims are: short waiting times appropriate to clinical need; a one-stop approach; clear communication with referrers; and more efficient use of resources.
The core role within a valve clinic is that of a cardiologist with specialist competencies in valve disease. Devolved surveillance, as practised predominantly within the UK, may be performed by sonographers or nurses under the auspices of the cardiologist.
Inclusion and exclusion criteria for devolved surveillance
Patients should initially be seen by a cardiologist who may assess them for devolved surveillance. This is appropriate when there is isolated valve disease requiring regular echocardiograms, but not to see a cardiologist. Patients with complex problems including multiple valve disease or arrhythmias or coronary disease are not suitable for devolved surveillance.
Patients who have bacteriologically cured infective endocarditis but have not had inpatient surgery should be followed after discharge because about 10% require surgery in the first year and the risks of surgery rise if performed as an emergency.
Patients with Marfan or bicuspid aortic valve are candidates for surveillance of the aorta.
Surveillance echocardiography is required after interventions: after mitral repair; or for biological replacement valves more than 5 years after implantation;2 or mechanical valves associated with paraprosthetic regurgitation or left or right ventricular dysfunction; or after transcatheter procedures; and ideally those with new designs of conventional biological valves because of uncertain durability.
Patients with normally functioning mechanical replacement valves do not need echocardiography after the initial postoperative study2 and could be considered for clinical surveillance in a nurse-led clinic9 rather than by a cardiologist if this accords with national arrangements.
Investigations required within valve clinics
Expert echocardiography is essential and the laboratory should ideally have formal European Association of Echocardiography or similar accreditation. In addition, treadmill exercise tests are indicated in apparently asymptomatic aortic stenosis because revealed symptoms are an indication for surgery.2 Exercise test are also useful in other types of valve disease to determine exercise capacity and confirm the absence of symptoms. Stress echocardiography is useful in cases in which uncertainty exists, for example, when symptoms occur in apparently moderate aortic or mitral stenosis. Neurohormone assays, especially B-type natriuretic hormone may also inform decisions concerning the timing of surgery. Cross-sectional imaging, CT and cardiac magnetic resonance, should be available for selected patients, although their place in the routine assessment of patients with valve disease is yet to be established. Cardiopulmonary exercise testing may be useful to differentiate respiratory from cardiac causes of breathlessness.
Qualification and training
There is, as yet, no formal qualification to establish competency in valve disease for any medical discipline. For a cardiologist, study at a specialised centre during training would be useful, and an essential criterion is attendance at valve-related training events formally designated by accreditation points from a representative national or international body. Specialised practice could be demonstrated by supervision of a valve clinic, being part of the endocarditis team, seeing inpatient referrals with valve disease, and writing departmental protocols. Ideal criteria include research or teaching in valve disease and membership of a specialist society, for example, the European Society of Cardiology Working Group in Valvular Heart Disease, the Society of Heart Valve Disease or the British Heart Valve Society. There will be a spectrum in valve-related activity between cardiologists and general practitioners who have competencies in valve disease and those, usually at cardiothoracic centres, who subspecialise partly or wholly in valve disease.
A surgeon will have received training in a recognised valve centre and must be able to demonstrate adequate numbers and quality of results according to standards available in opinion papers and defined by national specialist societies.12
Sonographers and nurses must have adequate experience and training, for example, ward or laboratory-based experience in cardiology. They should ideally have a higher degree in cardiology and may have attended hospital-based or national clinical skills courses and informal training in consultant-led cardiology clinics.
Criteria for discharge
The aims of the clinic will determine the suitability of patients seen. Most specialist valve clinics will care for all patients with valve disease. However, if the patient develops significant comorbidity and the valve disease is felt to be inoperable and of secondary importance, it may be more appropriate for care to be continued elsewhere, for example, an elderly care unit or heart failure clinic. In the UK, patients referred to a devolved sonographer-led clinic who are found to have complex cardiological or medical problems or in whom new problems arise should be referred back to a cardiologist-led clinic.
If the aim of the clinic is to ensure the correct timing of surgery it may not be appropriate to see patients with normally functioning prosthetic valves after surgery, although we believe best practice is to continue seeing such patients and an initial postoperative echocardiogram and clinical assessment is essential.
Patients found to have mild disease may be discharged to the community for re-referral should there be a clinical change, or arrangements may be made for routine 3–5-year call back to the clinic depending on local practice.
Funding and organisational issues
The prototype valve clinics evolved from research projects and conventional clinics and costs were often absorbed. New clinics must increasingly be justified by a business case, but detailed cost–benefit analyses are lacking. Although the quality of service improvement is obvious, formal evidence is only beginning to accumulate to facilitate economic calculations.7 Some costs are higher than for conventional cardiology clinics, for example, that of longer, more detailed echocardiograms and the immediate availability of B-type natriuretic peptide testing and exercise tests. On the other hand, there are major savings, for example, as a result of reductions in inappropriate tests7 ,13 ,14 and devolving surveillance from a cardiologist to a nurse or sonographer. Other cost savings are harder to estimate, for example, those derived from preventing endocarditis by advice about dental hygiene or antibiotic prophylaxis or as a result of reduced morbidity as a result of the correct timing of surgery.
Conclusion
We believe that valve disease should be the next cardiac pathology to receive attention following the success of previous programmes directed at heart failure and coronary disease. The organisation of care for valve disease is limited and there is a growing international consensus that specialist valve clinics will improve care and reduce costs.15 The clinics will be the core of a general valve service coordinated by a cardiologist with recognised competencies in valve disease. The key properties of these valve services will be: team-working with roles assigned according to the clinical requirements of each patient; specialisation to deliver expert care; concentration of expert investigations; and overarching protocols linking community, hospital and surgical centres.
References
Footnotes
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Contributors JBC prepared the manuscript. All other co-authors contributed significant modifications to the drafts and approved the final version.
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Competing interests None.
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Provenance and peer review Not commissioned; internally peer reviewed.