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Family screening in hypertrophic cardiomyopathy is underperformed, but can be improved by a specialised clinic A. Olaussen,1,2 A. Beale,1 I. Macciocca1,3 and A. H. Ellims1,4 1

HCM Clinic @ The Alfred, 2Monash University, 3Victorian Clinical Genetics Services, Murdoch Childrens Research Institute, and 4Baker IDI Heart and

Diabetes Research Institute, Melbourne, Victoria, Australia

Key words cardiomyopathy, hypertrophic, screening, echocardiography, phenotype. Correspondence Andris Harald Ellims, Alfred Hospital and Baker IDI Heart and Diabetes Research Institute, HCM Clinic @ The Alfred, Heart Centre, Alfred Hospital, Commercial Road, Melbourne, Vic. 3004, Australia. Email: [email protected] Received 14 March 2014; accepted 16 April 2014. doi:10.1111/imj.12460

Abstract Background: Hypertrophic cardiomyopathy (HCM) causes significant morbidity and sudden death. First-degree relatives (FDR) of affected patients are at risk due to autosomal dominant inheritance. Guidelines recommend clinical screening, including echocardiography, for all FDR. Aim: We sought to determine adherence to these guidelines, and whether a specialised HCM clinic improves screening rates. Method: This 12-month prospective follow-up study obtained family pedigrees from all patients referred to the HCM Clinic @ The Alfred. The number of living FDR was determined, and whether they had previously been assessed by echocardiography. One year after a coordinated clinic-based family screening approach was instituted, the number of additionally screened FDR was recorded. Results: Three hundred and eight living FDR of 61 HCM patients were identified. Of these, echocardiography had previously been performed in only 80 (26%), yielding 13 (16%) additional cases of HCM. Twelve months after attendance at our clinic, 51 additional FDR were screened (64% improvement) and 8 new cases of HCM were identified. Conclusions: Recommended family screening for HCM is underperformed, resulting in missed opportunities to detect subclinical HCM. A coordinated approach through a specialised HCM clinic improves screening rates, thus referral to such a service should be considered for all patients with HCM and their families.

Introduction Hypertrophic cardiomyopathy (HCM) is the commonest monogenic inherited cardiac disease and is defined by the presence of otherwise unexplained thickening of the muscular wall of the left ventricle (LV).1 Affecting approximately 1 in 500 people,1,2 HCM contributes to significant morbidity, and is a major cause of sudden cardiac death (SCD) in both children2 and young athletes.3 Inheritance is autosomal dominant, meaning there is a 50% risk for first-degree relatives (FDR) to carry the pathogenic mutation associated with HCM in their family and are, therefore, at risk of developing HCM. Clinical presentation of HCM is diverse.4 Symptoms include dyspnoea, chest pain, palpitations, dizziness and syncope. However, many remain asymptomatic and, in these patients, the first manifestation of the disease may

Funding: None. Conflict of interest: None. © 2014 The Authors Internal Medicine Journal © 2014 Royal Australasian College of Physicians

be SCD.1,5 The annual mortality rate in HCM is up to 5%1 and the 6-year survival rate is 91%.6 This mortality risk is a major incentive for performing family screening,7 as individuals at high risk for sudden death can be identified and offered a prophylactic implantable cardioverter defibrillator (ICD). Guidelines formulated by the Cardiac Society of Australia and New Zealand (CSANZ) recommend clinical screening of all FDR of HCM patients.8 Screening should include physical examination, electrocardiography (ECG) and echocardiography and occur regularly with a frequency determined by the age of the family relative. For example, screening every 1 to 1.5 years is recommended for those aged 11 to 20 years, a period during which phenotypic manifestations of HCM are most likely to occur, and every 3 to 5 years for those aged over 30 years.9 A specialised clinic was established at our institution in 2012 to improve both the understanding and management of HCM. The ‘HCM Clinic @ The Alfred’ accepts referrals from across Australia and is staffed by a 665

Olaussen et al.

multi-disciplinary team consisting of cardiologists, a cardiac surgeon and a genetic counsellor. Maximising the number of FDR that are properly screened for HCM is an important function of our clinic. We sought to determine the degree of adherence to the family screening guidelines of CSANZ in the FDR of patients referred to our specialised HCM clinic. Furthermore, we sought to implement simple and practical clinic-based interventions designed to improve the overall performance of family screening for HCM.

Methods Patient selection All research was performed at the Alfred Hospital, Melbourne, Australia. All patients referred to the clinic with a clinical diagnosis of HCM between February 2012 and March 2013 were included in the analysis. The study was conducted in accordance with the Alfred Hospital Ethics Committee’s guidelines. Patient demographic and clinical data were collected.

Initial assessment of the pedigree A detailed three-generation pedigree was obtained from all patients with HCM by a genetic counsellor at initial assessment. For each patient, the number of living FDR was first determined. Then, based on the patient’s knowledge, the number of these relatives who had previously undergone echocardiographic screening was ascertained. If more than one HCM patient from the same family was seen at the clinic, the number of unique FDR was calculated. Finally, the number of relatives who had been diagnosed with HCM as a result of echocardiographic screening was established. These patients were not labelled as at-risk. Patients had the opportunity, at their discretion, to contact FDR to clarify their screening status and results at a later time. FDR were also provided with contact details to provide our clinic voluntarily with the formal reports of their echocardiograms. Where there was uncertainty as to the screening status of an FDR, we assumed that screening had not been performed.

Clinic-based interventions to improve family screening During their initial assessment, each patient was advised of the autosomal dominant pattern of inheritance of HCM and the recommendation that all FDR should be screened for HCM with a clinical assessment, ECG and echocardiogram. This was communicated to each patient 666

during the initial assessment and subsequently through written correspondence addressed directly to the patient. The task of contacting FDR and advising them of these recommendations was made by patients, at their discretion. To facilitate this process, the patient received a letter explaining the rationale for the screening recommendations for relatives, the investigations that were necessary for screening as well as the contact details of the clinic which could be passed on directly to relatives. In circumstances where English was not a family’s preferred language, a translation of written correspondence into their preferred language was also provided. A clinical assessment was performed and referral for echocardiography was arranged for all FDR who accompanied their affected relative to the clinic. Follow-up 12 months after a patient’s initial clinic assessment, either during routine clinical follow up or through phone, was performed to record both the number of additional FDR who had been screened and new cases of HCM subsequently identified.

Analysis Normally distributed continuous variables were presented using mean ± standard deviation. Ordinal or skewed data were presented using median (interquartile range). To calculate statistical difference, student’s t-test was used between two means, Wilcoxon–Mann– Whitney test was used between two medians, and the Chi-squared (χ2) test was used between two proportions. For all comparisons, a P-value of

Family screening in hypertrophic cardiomyopathy is underperformed, but can be improved by a specialised clinic.

Hypertrophic cardiomyopathy (HCM) causes significant morbidity and sudden death. First-degree relatives (FDR) of affected patients are at risk due to ...
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