Valvular heart disease: new evidence and updated guidelines

My Post (14)Following new evidence in recent years, updated guidelines have been published for the management of valvular heart disease (VHD) by the European Society of Cardiology (ESC) and European Association for Cardio-Thoracic Surgery (EACTS). Since the last iteration of the Guidelines, randomised trials on percutaneous interventional techniques and risk-stratification regarding timing of intervention in VHD have made new recommendations necessary. Following new evidence in recent years, updated guidelines have been published for the management of valvular heart disease (VHD) by the European Society of Cardiology (ESC) and European Association for Cardio-Thoracic Surgery (EACTS). Since the last iteration of the Guidelines, randomised trials on percutaneous interventional techniques and risk-stratification regarding timing of intervention in VHD have made new recommendations necessary.

ESC Chairperson, Professor Helmut Baumgartner said:

‘Since the 2012 Guidelines, a large amount of new data have accumulated, particularly in the field of catheter interventional treatment of valvular heart disease.’

Valvular heart disease

VHD is a leading cause of morbidity and mortality worldwide, and refers to conditions where the heart’s valves do not work properly (British Heart Foundation (BHF), 2017). This in turn can affect flow of blood to the heart. The estimated prevalence of VHD in developed countries is 2.5% (Lung and Vahanian, 2014). Causes of VHD can be congenital or acquired, with prevalence increasing markedly in those over 65 years of age (Lung and Vahanian, 2017).

Valve stenosis, or narrowing, refers to a valve that does not open fully, which will obstruct or restrict the flow of blood (BHF, 2017). As the heart has to pump harder in order to force the blood past the narrowing, it can put extra strain on the heart (BHF, 2017). By contrast, valve regurgitation, or leaky valve, concerns a valve that is not able to close properly, and so will allow blood to leak backwards (BHF, 2017). Again, this can put strain on the heart, but this is because the heart has to work harder to pump the required volume of blood (BHF, 2017). While many people may not experience any noticeable physical effects, commonly reported symptoms include:

  • Breathlessness
  • Swelling of the ankles and feet
  • Fatigue (BHF, 2017).

Echocardiography

As was discussed in a recent issue of the British Journal of Cardiac Nursing, echocardiography is the gold standard to confirm a diagnosis of VHD, as well as to assess its severity and prognosis (Hall, 2017). It is also key to assess valve morphology and function, as well as to evalu¬ate the feasibility and indications of a specific intervention. Aortic stenosis is the most common VHD, leading to surgery or catheter intervention in Europe and the United States (US). Its growing prevalence is attributable to the ageing population. Echocardiography is used to:

  • Confirm the presence of aortic stenosis
  • Assess the degree of valve calcification, left-ventricle function and wall thickness
  • Detect the presence of other associated valve disease or aortic pathology
  • Provide prognostic information.

Baumgartner said:

‘In aortic stenosis, there have been five randomised clinical trials comparing surgical aortic valve replacement (SAVR) and transcatheter aortic valve implantation (TAVI) as well as large-scale registry data.’

The Guidelines strongly recommend early therapy in symptomatic patients with severe aortic stenosis. Exceptions are given to patients with severe comorbidities indicating a survival of less than a year, and patients in whom there are severe comorbidities, or their general condition at an advanced age make it unlikely that the intervention will improve their quality of life or survival.

SAVR and TAVI

SAVR is recommended in patients at low surgical risk, while TAVI is recommended in patients not suitable for surgery. For patients at increased surgical risk, the decision between SAVR and TAVI should be made by the heart team of surgeons and cardiologists, with TAVI being favoured in older patients suitable for transfemoral access.

The Guidelines stress that aortic valve interventions should only be performed in heart valve centres that include both cardiology and cardiac surgery on site. For asymptomatic patients, SAVR is indicated in those with severe aortic stenosis and systolic left-ventricular function not owing to another cause.

Baumgarter noted:

‘There is new evidence regarding predictors of outcome in asymptomatic patients with valvular heart disease and on antithrombotic therapy in this patient population among other innovations. This definitely required an update of management recom¬mendations.’

Baumgartner emphasised that risk score and age are not the only factors affecting the decision to use SAVR or TAVI:

‘The choice of surgical aortic valve replacement or transcatheter aortic valve implantation is not simply based on a risk score or age—the heart team must weigh the risks and benefits of both procedures, particularly in the intermediate risk situation. Discussion should include age, comorbidities, anatomy, and out¬comes of the centre for surgery and transcatheter intervention.’

Risk-stratification

Risk-stratification is an essential means of decision-making in this patient population in order to establish the risk of intervention compared with the expected natural history of VHD. The Guidelines call for the development of better risk-stratification tools, particularly for the decision between surgery and catheter intervention and for the avoidance of futile interventions.

In asymptomatic patients with VHD, studies suggest early surgery may improve outcomes. However, deciding when to intervene is controversial. For example, asymptomatic patients with aortic stenosis, who have pulmonary hypertension have been introduced into the criteria for being selected for surgery, following studies which showed it was a predictor of poor outcomes. But on the other hand, conflicting studies on the prognostic value of exercise echocardiographic parameters indicate the removal of asymptomatic patients with aortic stenosis and mitral regurgitation from the selection criteria.

Recommendations on the use of antithrombotic therapy have also been updated. Antithrombotic management should address effective control of modifiable risk factors for thromboembolism in addition to the prescription of antithrombotic drugs. The Guidelines state that there are now sufficient data to recommend non-vitamin K antagonist oral anticoagulants as an alternative to vitamin K antagonists in patients with atrial fibrillation who have aortic valve disease or mitral regurgitation. They do, however, point out that non-vitamin K antagonist oral anticoagulants remain contraindicated in patients with mechanical valves and in mitral stenosis.

Conclusion

These new Guidelines from ESC and EACTS represent a much-needed update on the management of VHD. They take into consideration new evidence on risk-stratification and the timing of intervention, as well as on percutaneous intervention techniques. They are aimed at both cardiologists and surgeons, and as Professor Volkmar Falk, EACTS Chairperson, highlights, it is important that both specialties follow the recommendations:

‘This is a joint guideline between cardiologists and surgeons. It is absolutely essential that both specialties follow the same recommendations because we are treating the same patients. Decisions in structural valve disease must be taken by a heart team of cardiologists and surgeons.’

References 

Baumgartner H, Falk V, Bax JJ et al. 2017. 2017 ESC/ EACTS Guidelines for the management of valvular heart disease. Eur Heart J. 2017;38(36):2739- 2791. https://doi.org/10.1093/eurheartj/ehx391

British Heart Foundation. Heart valve disease. 2017. http://tinyurl.com/yat7vjzt (accessed 15 December 2017)

Hall A. Suspected mitral valve disease: clinical assessment. Br J Cardiac Nurs. 2017;12(11):538- 546. https://doi.org/10.12968/bjca.2017.12.11.538

Lung B, Vahanian A. Epidemiology of acquired valvular heart disease. Can J Cardiol. 30(9):962-970. https://doi.org/10.1016/j.cjca.2014.03.022

Taken from British Journal of Cardiac Nursing, published December 2017.

Advertisements

First ESC Focused Update on dual antiplatelet therapy in CHD

My Post (8)The European Society of Cardiology (ESC) has published its first Focused Update on the use of dual antiplatelet therapy (DAPT) in coronary heart disease (CHD) (Valgimigli et al, 2017). Produced in collaboration with the European Society for Cardio-Thoracic Surgery (EACTS), the document addresses recommendations on a medical treatment that has seen conflicting advice over the years.

Conflicting evidence

According to Dr Marco Valgimigli, Chairperson of the ESC/EACTS Task Force, the conflicting evidence surrounding DAPT has resulted in many people calling it a controversial topic:

‘This has led to a great deal of uncertainty in the medical community, particularly regarding the optimal duration of DAPT after coronary stenting,’ he said.

A survey initiated by the European Association of Percutaneous Cardiovascular Interventions sought opinions from the medical community on the evidence relating to DAPT duration after coronary stenting (Valgimigli et al, 2015). It revealed considerable uncertainty over optimal duration of DAPT after stenting and therefore called for updated recommendations for practising physicians to guide treatment decisions.

Neglected populations

Alongside conflicting results in the published literature on DAPT, there is also limited evidence on various patient subsets—such as elderly patients—who may have a greater bleeding risk. Here, the benefits and risks of DAPT may be different to those seen in more selected patient cohorts included in randomised controlled trials. The aim of this Focused Update therefore is to address the current recommendations on DAPT in patients with CHD.

Dual antiplatelet therapy

Being one of the most intensively investigated treatments in cardiovascular medicine, there have been 35 randomised clinical trials of DAPT, including more than 225 000 patients. The first randomised clinical trial to establish the superiority of DAPT over anticoagulant therapy among patients undergoing percutaneous coronary intervention was published in 1996.

Platelets are small particles in the blood that can clump together to form clots; these can go on to cause myocardial infarction or the occlusion of a coronary stent. Antiplatelet agents are a class of drugs that are used to stop platelets from forming these clots. The use of two types of antiplatelet agents to prevent blood clotting is known as DAPT (American Heart Association, 2017).

The number of patients requiring dual antiplatelet therapy consisting of the combination of aspirin and an oral inhibitor of the platelet P2Y12 receptor for adenosine 5’-diphosphate has increased over time. In Europe, it is believed that around 1 400 000 patients per year may have an indication for DAPT after coronary intervention, and 2 200 000 after myocardial infarction.

P2Y12 inhibitors range from safer drugs, such as ticlopidine or clopidogrel, to the more potent and predictable, such as ticagrelor or prasugrel. The decision on when to initiate a P2Y12 inhibitor depends on both the specific drug and the disease.

DAPT reduces the risk of stent thrombosis from occurrences ranging from acute to late events. It also reduces the rate of spontaneous myocardial infarction after percutaneous coronary intervention and myocardial infarction.

For patients with stable CHD treated with percutaneous coronary intervention, the default P2Y12 inhibitor is considered to be clopidogrel. It is also commonly the default drug for patients with indication to concomitant oral anticoagulation, and in patients with acute coronary syndromes in whom ticagrelor or prasugrel are contraindicated. Ticagrelor or prasugrel is recommended in people with acute coronary syndromes unless drug-specific contraindications exist.

Recommendations for DAPT

A Task Force made up of selected medical experts carried out a comprehensive review of the published evidence for management of CHD according to ESC Committee for Practice Guidelines policy, and approved by the EACTS. A critical evaluation of diagnostic and therapeutic procedures took place, including assessment of the risk–benefit ratio. The level of evidence and the strength of the recommendation of particular management options were then weighed and graded according to predefined scales.

The Focused Update recommends a default DAPT duration of 12 months for patients with acute coronary syndrome. This is irrespective of revascularisation therapy, whether through medical therapy, percutaneous coronary intervention or coronary artery bypass surgery. In patients with high bleeding risk, 6 months of DAPT should be considered. Therapy over 12 months may be considered in patients with acute coronary syndrome who have tolerated DAPT without a bleeding complication.

The Task Force felt that the need for a short DAPT regimen should no longer justify the use of bare metal stents instead of newer generation drug-eluting stents. An assessment of the individual patient’s ischaemic risks versus bleeding risks should be used to establish duration of DAPT rather than the type of stent used.

For patients with CHD being treated with percutaneous coronary intervention who are believed to be stable, the duration of DAPT should be 1–6 months, depending on the bleeding risk. This is irrespective of the type of metallic stent implanted. For patients whose ischaemic risk is thought to be greater than the risk of bleeding, the Focused Update recommends a longer DAPT duration. The Task Force felt that there were insufficient data to recommend DAPT in patients with stable CHD treated with coronary artery bypass graft surgery.

The most controversial issue cited was the need for a prolonged DAPT regimen (anything over 12 months) in patients with acute coronary syndrome treated with percutaneous coronary intervention. This is owing to concern over ensuring benefits while diminishing risks.

‘This is a setting in which one needs to think twice about how to maximise the benefits over the risks,’ said Dr Valgimigli. ‘The most novel and important message here is that DAPT is a regimen to treat a patient, not the previously implanted stent. This is crucial and the community needs to adapt to this new treatment paradigm.’

Differing types and durations of DAPT therapy have not been seen as necessary for male and female patients, instead calling for a similar approach to care. Additionally, no difference in therapy is required for patients with diabetes.

Dr Valgimigli said:

‘The Task Force advocates a personalised medicine approach where each treatment and its duration is individualised as much as possible. The document highlights who should, and should not, receive long-term treatment, while at the same time outlining how to maximise the expected benefits over the risks.’

Conclusion

This year marks the 21st anniversary of the first randomised clinical trial that established the superiority of DAPT over anticoagulant therapy among patients undergoing percutaneous coronary intervention. However, differing advice on optimal duration of DAPT after coronary stenting makes this Focused Update long overdue—though it should go some way to guiding treatment decisions. BJCN

References

American Heart Association. 2017. What is Dual Antiplatelet Therapy (DAPT) [Internet]? Available from http://tinyurl.com/yajb9wmx

Valgimigli M, Costa F, Byrne R, Haude M, Baumbach A, Windecker S. Dual antiplatelet therapy duration after coronary stenting in clinical practice: results of an EAPCI survey. EuroIntervention. 2015;11(1):68-74. https://doi.org/10.4244/EIJV11I1A11

Valgimigli M, Bueno H, Byrne RA et al. 2017 ESC focused update on dual antiplatelet therapy in coronary artery disease developed in collaboration with EACTS: The Task Force for dual antiplatelet therapy in coronary artery disease of the European Society of Cardiology (ESC) and of the European Association for Cardio-Thoracic Surgery (EACTS). Eur Heart J; 2017. https://doi.org/10.1093/eurheartj/ehx419. [Epub ahead of print]

Taken from British Journal of Cardiac Nursing, published December 2017.