The variable spectrum of anterior mitral valve leaflet restriction in rheumatic heart disease screening.

INTRODUCTION: The World Heart Federation (WHF) screening criteria do not incorporate a strict, reproducible definition of anterior mitral valve leaflet (AMVL) restriction. Using a novel definition, we have identified two distinct AMVL restriction configurations. The first, called "distal tip" AMVL restriction is associated with additional morphological features of rheumatic heart disease (RHD), while the second, "gradual bowing" AMVL restriction is not. This "arch-like" leaflet configuration involves the base to tip of the medial MV in isolation. We hypothesize that this configuration is a normal variant. METHODOLOGY: The prevalence and associated leaflet configurations of AMVL restriction were assessed in schoolchildren with an established "very low" (VLP), "high" (HP), and "very high" prevalence (VHP) of RHD. RESULTS: 936 studies were evaluated (HP 577 cases; VLP 359 cases). Sixty-five cases of "gradual bowing" AMVL restriction were identified in the HP cohort (11.3%, 95% CI 8.9-14.1) and 35 cases (9.7%, 95% CI 7-13.2) in the VLP cohort (P = .47). In the second analyses, an enriched cohort of 43 studies with proven definite RHD were evaluated. "Distal tip" AMVL restriction was identified in all 43 VHP cases (100%) and affected the central portion of the AMVL in all cases. CONCLUSION: "Gradual bowing" AMVL restriction appears to be a normal, benign variant of the MV, not associated with RHD risk nor with any other morphological features of RHD. Conversely, "Distal tip" AMVL restriction was present in all cases in the VHP cohort with no cases exhibiting a straight, nonrestricted central portion of the AMVL. This novel finding requires further investigation as a potential RHD rule-out test of the MV.

Screening for rheumatic heart disease: The reliability of anterior mitral valve leaflet thickness measurement.

BACKGROUND: Studies determining the reliability of the World Heart Federation (WHF) anterior mitral valve leaflet (AMVL) measurement are limited by the introduction of bias in their test-retest analyses. This study sought to determine the reliability of the current AMVL measurement while controlling for systematic bias. METHODS: Retrospective analysis of echocardiographic data from 16 patients with previous acute rheumatic fever was performed. Included in this study was an optimized cine loop of the mitral valve (MV) [reader-optimized measurement (ROM]) in the parasternal long-axis view and an optimized still image of the MV obtained from the same cine loop [specialist-optimized image (SOI)]. Each still image and associated cine loop was quadruplicated and randomized to determine intra- and inter-rater agreement and quantify the impact of zoom on AMVL measurement. RESULTS: Specialist-optimized image without zoom reflected the highest degree of agreement in both cohorts with an ICC of 0.29 and 0.46. The agreement in ROM images without zoom was ICC of 0.23 and 0.45. The addition of zoom to SOI decreased agreement further to an ICC of 0.20 and 0.36. The setting associated with the poorest agreement profile was ROI with zoom with an ICC of 0.13 and 0.34, respectively. The intra-rater agreement between readers in both cohorts was moderate across all settings with an ICC ranging between 0.64 and 0.86. CONCLUSIONS: The WHF AMVL measurement is only moderately repeatable within readers and demonstrates poor reproducibility that was not improved by the addition of a zoom-optimized protocol. Given our study findings, we cannot advocate the current WHF AMVL measurement as a reliable assessment for RHD.

Early surgery determines prognosis in patients with infective endocarditis: outcome in patients managed by an Endocarditis Team-a prospective cohort study.

Background: Infective endocarditis (IE) in South Africa is associated with significant morbidity and mortality, despite occurring in younger patients with fewer co-morbidities. Possible contributors include the high rates of blood culture negative endocarditis, high rates of mechanical valve replacement and the lack of inter-disciplinary coordination during management. Methods: The Tygerberg Endocarditis Cohort (TEC) study prospectively enrolled patients with IE between November 2019 and April 2021. All patients were managed by an Endocarditis Team with a set protocol for organism detection and a strategy of early surgery limiting the use of prosthetic material. Results: Seventy-two consecutive patients with IE were included, with a causative organism identified in 86.1% of patients. The majority of patients had a guideline indication for surgery (n=58; 80.6%). The in-hospital mortality rate was 18%, with a 6-month mortality rate of 25.7%. Surgery was performed in 42 patients (58.3%), with prosthetic valve (PVE) replacement in 32 (76.2%), conventional repair surgery in 8 (19.1%) and mitral valve reconstruction in 2 (4.8%) of patients. Patients who underwent surgery had a significantly lower in-hospital (4.8% vs. 56.3%; P<0.01) and 6-month (4.9% vs. 75.0%; P<0.01) mortality rate as compared with patients with an indication for surgery who did not undergo surgery. Conclusions: We have observed a reduction in the 6-month mortality rate in patients with IE following the establishment of an Endocarditis Team, adhering to a set protocol for organism detection and favouring early repair or reconstruction surgery. Patients who underwent surgery had a significantly lower mortality rate than patients with an indication for surgery who did not undergo surgery. Preventable residual mortality was driven by surgical delay.

Screening for subclinical rheumatic heart disease: addressing borderline disease in a real-world setting.

Aims: The World Heart Federation (WHF) criteria identify a large borderline rheumatic heart disease (RHD) category that has hampered the implementation of population-based screening. Inter-scallop separations (ISS) of the posterior mitral valve leaflet, a recently described normal variant of the mitral valve, appears to be an important cause of mild mitral regurgitation (MR) leading to misclassification of cases as WHF 'borderline RHD'. This study aims to report the findings of the Echo in Africa project, a large-scale RHD screening project in South Africa and determine what proportion of borderline cases would be re-classified as normal if there were a systematic identification of ISS-related MR. Methods and results: A prospective cross-sectional study of underserved secondary schools in the Western Cape was conducted. Participants underwent a screening study with a handheld (HH) ultrasound device. Children with an abnormal HH study were re-evaluated with a portable laptop echocardiography machine. A mechanistic evaluation was applied in cases with isolated WHF 'pathological' MR (WHF 'borderline RHD'). A total of 5255 participants (mean age 15± years) were screened. A total of 3439 (65.8%) were female. Forty-nine cases of WHF 'definite RHD' [9.1 cases/1000 (95% confidence interval, CI, 6.8-12.1 cases/1000)] and 104 cases of WHF 'borderline RHD' [19.5 cases/1000 (95% CI, 16.0-23.7 cases/1000)] were identified. Inter-scallop separations-related MR was the underlying mechanism of MR in 48/68 cases classified as WHF 'borderline RHD' with isolated WHF 'pathological' MR (70.5%). Conclusion: In a real-world, large-scale screening project, the adoption of a mechanistic evaluation based on the systematic identification of ISS-related MR markedly reduced the number of WHF 'screen-positive' cases misclassified as WHF 'borderline RHD'. Implementing strategies that reduce this misclassification could reduce the cost- and labour burden on large-scale RHD screening programmes.