Downloaded from http://heart.bmj.com/ on March 3, 2015 - Published by group.bmj.com
Heart Online First, published on February 19, 2015 as 10.1136/heartjnl-2014-306776 Editorial
The New European Society of Cardiology guidelines on hypertrophic cardiomyopathy Perry Elliott Hypertrophic cardiomyopathy (HCM) is a heart muscle disease that affects an estimated 1 in 500 adults in the general population. Many people with HCM live healthy lives, but its association with premature death in the young and heart failure in the middle aged raises its profile in the mind of the general public and make it a common cause for concern among healthcare professionals. To assist practitioners and patients manage the condition, The European Society of Cardiology (ESC) has recently published a new clinical practice guideline on HCM that replaces an earlier document produced jointly with the American College of Cardiology in 2003.1 From the outset, all members of the ESC writing committee agreed to three guiding principles while preparing their recommendations. The first was that guidance should be practical and firmly rooted in real-life clinical practice; second, there was a determination that recommendations should, where humanly possible, innovate and not slavishly reproduce previous statements; and finally–and perhaps most challenging of all—recommendations should, whenever possible, be based on the best scientific evidence. At first glance, the absence of large randomised clinical trials and the relative paucity of large cohort studies in this area of medicine might seem to render such ideals futile, but the experts on the committee were able to achieve consensus on an approach to diagnosis and management that shifts the emphasis towards multidisciplinary working and individualisation of patient care. Some of the most important areas covered in the guideline are discussed below.
AETIOLOGICAL DIVERSITY HCM is defined by a simple measurement of LV wall thickness on cardiac imaging. While this has been shown to be a robust and reproducible approach to clinical classification, it fails to describe the spectrum Correspondence to Professor Perry Elliott, The Inherited Cardiovascular Disease Unit, University College London, The Heart Hospital, 16-18 Westmoreland Street, London W1G 8PH, UK; perry. [email protected]
of genetic and non-genetic disorders than can present with LV thickening. One approach to rationalising this complexity is to confine the term HCM to a much narrower range of conditions—for example, those caused by mutations in sarcomeric protein genes—but this assumes that a thorough and comprehensive search for possible aetiologies is routine in everyday practice. The ESC committee felt that diagnostic accuracy (and therefore patient care) is more likely to be improved by promotion of a deliberate search for diagnostic clues or ‘red flags’ built on careful history taking, analysis of family pedigrees and a cardiomyopathy-centred interpretation of commonly used diagnostic tools such as electrocardiography and cardiac imaging.2 This philosophy is reflected in all sections of the guideline dedicated to diagnosis.
GENETIC TESTING In most cases, HCM is a heritable genetic trait.3 The majority of genetic forms of the disease are caused by mutations in one of eight cardiac sarcomeric protein genes, with a smaller proportion caused by inherited metabolic disorders, syndromes and neuromuscular disease. The ESC guidelines provide a clinically focussed approach to the requesting and interpretation of genetic tests, with a strong emphasis on the role of expert counselling before and after genetic analysis. The goal is to raise awareness of the many issues that can arise following the diagnosis of a genetic disease, including the risk of transmission to family members and the implications of a genetic diagnosis for insurance prospects, employment and reproductive advice. If due care is not given to such matters, considerable harm can be done to individuals and their relatives.
MANAGEMENT OF LV OUTFLOW TRACT OBSTRUCTION Dynamic LV outflow tract obstruction caused by systolic contact between the mitral valve leaflet and the interventricular septum is a common feature of HCM that impairs exercise tolerance and which, over time, leads to atrial dilatation and arrhythmia. In some respects, the section of the Elliott P. Heart April 2015 Vol 101 No 7
guidelines dedicated to this topic is the least altered from previous versions as the drugs and invasive procedures used to treat LV outflow tract obstruction are supported by an extensive historical literature and have remained largely unchanged over the past decade. However, the ESC committee was able to develop a simple but systematic approach to the assessment of obstruction that can be used to tailor therapies to the characteristics of individual patients (figure 1). This is important as the phenomenon of LV outflow tract obstruction is complex—reflecting the interaction of altered septal geometry, mitral leaflet elongation and abnormalities of the submitral apparatus—and is highly variable. This means that in some patients therapies such as alcohol ablation or isolated septal myectomy are inappropriate or at least likely to be suboptimal.
PREVENTION OF SUDDEN CARDIAC DEATH Although the risk of sudden death is low for most patients with HCM, a small number are prone to life-threatening ventricular arrhythmias. Previous guidelines have suggested that patients with HCM should be risk stratified using one or more clinical features known to associate with sudden death. Most evidence suggests that this approach does identify a group of patients who have an increased relative risk of sudden death compared with those without major risk factors, but it also has some important limitations, not least of which is a failure to provide an individualised estimate of absolute risk. One of the most important innovations in the new guideline is the adoption of a new validated risk calculator (HCMRisk-SCD) that uses simple clinical measures to provide such an estimate.4 Some general guidance on the use of this tool as an aid to treatment decisions is provided (figure 2), but perhaps the greatest advance is the use of absolute rather than relative risk as this brings into stark relief the balance between the efficacy of interventions (in this case implantable cardioverter defibrillators) on the one hand and the potential risks and costs of therapy to individual patients and healthcare economies on the other.
MANAGEMENT OF HEART FAILURE The treatment of heart failure symptoms in patients with HCM is challenging and, unlike most other diseases that cause symptomatic ventricular dysfunction, is almost entirely unsupported by randomised clinical trials. Yet again, however, this is an example of how an understanding of complexity aids rather than hinders clinical decision-making. 1
Copyright Article author (or their employer) 2015. Produced by BMJ Publishing Group Ltd (& BCS) under licence.
Downloaded from http://heart.bmj.com/ on March 3, 2015 - Published by group.bmj.com
Editorial
Figure 1 Check list for patients being considered for invasive septal reduction therapies (Reproduced with permission from Elliott et al [1]).
The term heart failure in this setting refers to very different clinical profiles that require specific approaches to therapy.5 In the early stages of the disease, patients are often asymptomatic and conventional noninvasive indices of cardiac performance are within the normal range. As the condition progresses, there is a decline in LV diastolic and systolic function that can be associated with either LV dilation, decreased LV wall thickness and a fall in EF, or severe LV diastolic dysfunction and atrial dilation with little or no LV dilation. It can be anticipated that ACE inhibitors may be helpful in patients with severe systolic impairment, but harmful in patients with small ventricular cavities and high diastolic pressures. The ESC guidelines stress the limitation of EF as a measure of systolic performance in this complex setting by raising the threshold at which severe systolic impairment should be suspected.
LIVING WITH HCM Perhaps for the first time in an international guideline, a checklist of practical 2
everyday issues that affect the lives of patients with HCM is provided. One of the most important issues arises from the fact that HCM presents mostly in individuals aged
Heart Online First, published on February 19, 2015 as 10.1136/heartjnl-2014-306776 Editorial
The New European Society of Cardiology guidelines on hypertrophic cardiomyopathy Perry Elliott Hypertrophic cardiomyopathy (HCM) is a heart muscle disease that affects an estimated 1 in 500 adults in the general population. Many people with HCM live healthy lives, but its association with premature death in the young and heart failure in the middle aged raises its profile in the mind of the general public and make it a common cause for concern among healthcare professionals. To assist practitioners and patients manage the condition, The European Society of Cardiology (ESC) has recently published a new clinical practice guideline on HCM that replaces an earlier document produced jointly with the American College of Cardiology in 2003.1 From the outset, all members of the ESC writing committee agreed to three guiding principles while preparing their recommendations. The first was that guidance should be practical and firmly rooted in real-life clinical practice; second, there was a determination that recommendations should, where humanly possible, innovate and not slavishly reproduce previous statements; and finally–and perhaps most challenging of all—recommendations should, whenever possible, be based on the best scientific evidence. At first glance, the absence of large randomised clinical trials and the relative paucity of large cohort studies in this area of medicine might seem to render such ideals futile, but the experts on the committee were able to achieve consensus on an approach to diagnosis and management that shifts the emphasis towards multidisciplinary working and individualisation of patient care. Some of the most important areas covered in the guideline are discussed below.
AETIOLOGICAL DIVERSITY HCM is defined by a simple measurement of LV wall thickness on cardiac imaging. While this has been shown to be a robust and reproducible approach to clinical classification, it fails to describe the spectrum Correspondence to Professor Perry Elliott, The Inherited Cardiovascular Disease Unit, University College London, The Heart Hospital, 16-18 Westmoreland Street, London W1G 8PH, UK; perry. [email protected]
of genetic and non-genetic disorders than can present with LV thickening. One approach to rationalising this complexity is to confine the term HCM to a much narrower range of conditions—for example, those caused by mutations in sarcomeric protein genes—but this assumes that a thorough and comprehensive search for possible aetiologies is routine in everyday practice. The ESC committee felt that diagnostic accuracy (and therefore patient care) is more likely to be improved by promotion of a deliberate search for diagnostic clues or ‘red flags’ built on careful history taking, analysis of family pedigrees and a cardiomyopathy-centred interpretation of commonly used diagnostic tools such as electrocardiography and cardiac imaging.2 This philosophy is reflected in all sections of the guideline dedicated to diagnosis.
GENETIC TESTING In most cases, HCM is a heritable genetic trait.3 The majority of genetic forms of the disease are caused by mutations in one of eight cardiac sarcomeric protein genes, with a smaller proportion caused by inherited metabolic disorders, syndromes and neuromuscular disease. The ESC guidelines provide a clinically focussed approach to the requesting and interpretation of genetic tests, with a strong emphasis on the role of expert counselling before and after genetic analysis. The goal is to raise awareness of the many issues that can arise following the diagnosis of a genetic disease, including the risk of transmission to family members and the implications of a genetic diagnosis for insurance prospects, employment and reproductive advice. If due care is not given to such matters, considerable harm can be done to individuals and their relatives.
MANAGEMENT OF LV OUTFLOW TRACT OBSTRUCTION Dynamic LV outflow tract obstruction caused by systolic contact between the mitral valve leaflet and the interventricular septum is a common feature of HCM that impairs exercise tolerance and which, over time, leads to atrial dilatation and arrhythmia. In some respects, the section of the Elliott P. Heart April 2015 Vol 101 No 7
guidelines dedicated to this topic is the least altered from previous versions as the drugs and invasive procedures used to treat LV outflow tract obstruction are supported by an extensive historical literature and have remained largely unchanged over the past decade. However, the ESC committee was able to develop a simple but systematic approach to the assessment of obstruction that can be used to tailor therapies to the characteristics of individual patients (figure 1). This is important as the phenomenon of LV outflow tract obstruction is complex—reflecting the interaction of altered septal geometry, mitral leaflet elongation and abnormalities of the submitral apparatus—and is highly variable. This means that in some patients therapies such as alcohol ablation or isolated septal myectomy are inappropriate or at least likely to be suboptimal.
PREVENTION OF SUDDEN CARDIAC DEATH Although the risk of sudden death is low for most patients with HCM, a small number are prone to life-threatening ventricular arrhythmias. Previous guidelines have suggested that patients with HCM should be risk stratified using one or more clinical features known to associate with sudden death. Most evidence suggests that this approach does identify a group of patients who have an increased relative risk of sudden death compared with those without major risk factors, but it also has some important limitations, not least of which is a failure to provide an individualised estimate of absolute risk. One of the most important innovations in the new guideline is the adoption of a new validated risk calculator (HCMRisk-SCD) that uses simple clinical measures to provide such an estimate.4 Some general guidance on the use of this tool as an aid to treatment decisions is provided (figure 2), but perhaps the greatest advance is the use of absolute rather than relative risk as this brings into stark relief the balance between the efficacy of interventions (in this case implantable cardioverter defibrillators) on the one hand and the potential risks and costs of therapy to individual patients and healthcare economies on the other.
MANAGEMENT OF HEART FAILURE The treatment of heart failure symptoms in patients with HCM is challenging and, unlike most other diseases that cause symptomatic ventricular dysfunction, is almost entirely unsupported by randomised clinical trials. Yet again, however, this is an example of how an understanding of complexity aids rather than hinders clinical decision-making. 1
Copyright Article author (or their employer) 2015. Produced by BMJ Publishing Group Ltd (& BCS) under licence.
Downloaded from http://heart.bmj.com/ on March 3, 2015 - Published by group.bmj.com
Editorial
Figure 1 Check list for patients being considered for invasive septal reduction therapies (Reproduced with permission from Elliott et al [1]).
The term heart failure in this setting refers to very different clinical profiles that require specific approaches to therapy.5 In the early stages of the disease, patients are often asymptomatic and conventional noninvasive indices of cardiac performance are within the normal range. As the condition progresses, there is a decline in LV diastolic and systolic function that can be associated with either LV dilation, decreased LV wall thickness and a fall in EF, or severe LV diastolic dysfunction and atrial dilation with little or no LV dilation. It can be anticipated that ACE inhibitors may be helpful in patients with severe systolic impairment, but harmful in patients with small ventricular cavities and high diastolic pressures. The ESC guidelines stress the limitation of EF as a measure of systolic performance in this complex setting by raising the threshold at which severe systolic impairment should be suspected.
LIVING WITH HCM Perhaps for the first time in an international guideline, a checklist of practical 2
everyday issues that affect the lives of patients with HCM is provided. One of the most important issues arises from the fact that HCM presents mostly in individuals aged
