High burden of rheumatic heart disease confirmed by echocardiography among Pacific adults living in New Zealand.

BACKGROUND: Despite numerous echocardiographic screening studies of children in high incidence acute rheumatic fever (ARF)/rheumatic heart disease (RHD) communities, little is known about the prevalence of RHD in adults in these populations.We sought to determine the prevalence of RHD in an urban area of South Auckland, New Zealand, where previous studies had shown the prevalence of RHD in children to be around 2%. METHODS: A cross-sectional screening study was conducted between 2014 and 2016. Echocardiography clinics were conducted at an urban Pacific-led primary healthcare clinic in New Zealand. Eligible persons aged 16-40 years were recruited according to a stratified randomised approach. Echocardiograms were performed with a standardised image acquisition protocol and reported by cardiologists. RESULTS: There were 465 individuals who underwent echocardiograms. The overall prevalence of RHD (define and borderline) was 56 per 1000 (95% CI 36 to 78 per 1000). Definite RHD was found in 10 individuals (4 of whom were already under cardiology review at a hospital clinic) with a prevalence of 22 per 1000 (95% CI 9 to 36 per 1000). Non-rheumatic cardiac abnormalities were found in 29 individuals. CONCLUSIONS: There is a high burden of both rheumatic and non-rheumatic cardiac abnormalities in this population. Rates described in New Zealand are as high as lower-middle-income countries in Africa. Addressing knowledge gaps regarding the natural history of RHD detected by echocardiography in adults is a priority issue for the international RHD community.

Echocardiography for latent rheumatic heart disease in first degree relatives of children with acute rheumatic fever: Implications for active case finding in family members.

BACKGROUND: Individuals with Acute Rheumatic Fever (ARF) often report a family history of ARF or Rheumatic Heart Disease (RHD) however the degree of familial susceptibility to RHD is poorly defined. This study aimed to determine RHD prevalence among first degree relatives of ARF patients using echocardiography. METHODS: Children with ARF were recruited from Auckland, New Zealand. Parents and siblings ≥ 4years were offered echocardiography. Echocardiograms were reported according to World Heart Federation 2012 criteria. RHD prevalence in first degree relatives was compared to previously established population rates in the region. FINDINGS: In total, 70 index cases with ARF were recruited. Echocardiography was performed in 94 parents and 132 siblings. There were 3 siblings with definite RHD and 9 with borderline RHD. There were 4 parents with definite RHD. Overall prevalence of RHD (definite and borderline) in siblings was 90/1,000 (95% CI 45-143/1,000) compared to 36/1,000 (95% CI 30-42/1,000) in New Zealand children from high ARF incidence populations (p 0.001). Prevalence of definite RHD in parents was 42/1,000 (95% CI 7-87/1,000) compared to 22/1,000 (95% CI 9-36/1,000) in adults from a high ARF incidence New Zealand population (p 0.249). INTERPRETATION: RHD prevalence in siblings and parents of ARF cases is significantly greater than in comparable background populations. The contribution of hereditary versus environmental risk factors remains uncertain. We recommend targeted echocardiographic case-finding among siblings and parents of ARF/RHD cases in order to detect previously unrecognized latent RHD.

The World Heart Federation criteria raise the threshold of diagnosis for mild rheumatic heart disease: Three reviewers are better than one.

BACKGROUND: The World Heart Federation (WHF) criteria, published in 2012, provided an evidence-based guideline for the minimal diagnosis of echocardiographically-detected RHD. Primary aim of the study was to determine whether use of the WHF criteria altered the threshold for the diagnosis of echocardiographically-detected RHD compared with the previous WHO/NIH criteria. A secondary aim was to explore the utility of a three reviewer reporting system compared to a single or two reviewer reporting structure. METHODS: 144 de-identified echocardiograms (RHD, congenital valvar abnormality, physiological valvar regurgitation) were independently reported using the WHF criteria by two reviewers blinded to the previous WHO/NIH diagnosis. If there was discordance between the two reviewers, a third cardiologist independently performed a tie-breaker review. RESULTS: There was a 21% reduction of cases classified as RHD using the WHF criteria compared to the modified WHO/NIH criteria (68 cases compared to 86, p = 0.04). There was a 60% consensus across the different diagnostic categories with 2 reviewers, 89% majority agreement with 3 reviewers. 11% required an open label discussion. There was moderate agreement between 2 reviewers for any RHD, kappa 0.57 (CI 0.44-0.70), with no significant difference in agreement between the different categories. CONCLUSION: The WHF criteria have raised the threshold for the diagnosis of RHD compared to the WHO/NIH criteria. However, inter-reporter variability of the WHF criteria is high. A three reviewer system is likely more accurate than a single or two reporter system for the diagnosis of mild RHD. This has resource implications for echocardiographic screening programmes.

Adequate adherence to benzathine penicillin secondary prophylaxis following the diagnosis of rheumatic heart disease by echocardiographic screening.

AIMS: The primary aim of this study was to determine adherence to benzathine penicillin (BPG) for individuals diagnosed with rheumatic heart disease (RHD) by echocardiographic screening between 2007-2012. METHODS: BPG records were obtained for 57 patients, median age 12 at time of diagnosis. A 'days at risk' analysis was undertaken. Annual adherence was calculated for each individual. A comparison with the Wellington region's Rheumatic Fever 2013 adherence data was undertaken. RESULTS: Adherence to BPG was good with a median follow-up time of 5.8 years. Days at risk analysis: median 0% at year one and 2.7% at year five. The median adherence for the entire cohort over the entire follow-up period was 92%, range 0-100%. There was no difference of proportions of late doses compared to the Wellington region. Median adherence was higher for register based (94%, n=48) compared to primary health care penicillin delivery (37%, n=7), p<0.005. During follow-up, 30% of the cohort moved between regions or overseas. CONCLUSIONS: Good adherence rates are achievable for secondary prophylaxis when RHD is diagnosed by echocardiographic screening. This likely reflects the benefit of rheumatic fever registers and community nursing services rather than the pathway of the diagnosis for RHD.

Normal echocardiographic mitral and aortic valve thickness in children.

OBJECTIVE: We aimed to define the normal range of aortic and mitral valve thickness in healthy schoolchildren from a high prevalence rheumatic heart disease (RHD) region, using a standardised protocol for imaging and measurement. METHODS: Measurements were performed in 288 children without RHD. Anterior mitral valve leaflet (AMVL) thickness measurements were performed at the midpoint and tip of the leaflet in the parasternal long axis (PSLA) in diastole, when the AMVL was approximately parallel to the ventricular septum. Thickness of the aortic valve was measured from PSLA imaging in systole when the leaflets were at maximum excursion. The right coronary and non-coronary closure lines of the aortic valve were measured in diastole in parasternal short axis (PSSA) imaging. Results were compared with 51 children with RHD classified by World Heart Federation diagnostic criteria. RESULTS: In normal children, median AMVL tip thickness was 2.0 mm (IQR 1.7-2.4) and median AMVL midpoint thickness 2.0 mm (IQR 1.7-2.4). The median aortic valve thickness was 1.5 mm (IQR 1.3-1.6) in the PSLA view and 1.4 mm (IQR 1.2-1.6) in the PSSA view. The interclass correlation coefficient for the AMVL tip was 0.85 (0.71 to 0.92) and for the AMVL midpoint was 0.77 (0.54 to 0.87). CONCLUSIONS: We have described a standardised method for mitral and aortic valve measurement in children which is objective and reproducible. Normal ranges of left heart valve thickness in a high prevalence RHD population are established. These results provide a reference range for school-age children in high prevalence RHD regions undergoing echocardiographic screening.