Letter by Beniwal and Bhaya Regarding Article, “Rheumatic Heart Disease Screening by Echocardiography: The Inadequacy of World Health Organization Criteria for Optimizing the Diagnosis of Subclinical Disease”
To the Editor:
Marijon and colleagues1 base their arguments on a phenomenon not observed by them during their study on rheumatic heart disease (RHD). They assume that “pathophysiologically, repeated rheumatic carditis can result in subvalvular or valvular thickening before the development of leaflet retraction and thereby regurgitation.” They further state, “In adding the diagnostic criterion of morphological valve changes, otherwise well defined in more advanced rheumatic valve lesions, we have detected many children with subclinical RHD but without significant valve regurgitation who would not be eligible for secondary RHD prophylaxis under current international guidelines.”
A phenomenon of dissociation between mild- to moderate-grade RHD-like valve abnormalities and significant regurgitation in about a fifth of the cases has been reported recently by Bhaya et al.2 They had adopted a strategy of universal definitive echocardiography for all of the enrolled schoolchildren without any intervening screening round of auscultation or echocardiography to remove any chance of selection bias while attempting to evaluate and improvise on the World Health Organization criteria for probable RHD.
Marijon et al had adopted a strategy of an initial screening round of echocardiography to identify cases with any regurgitation (physiological/significant) of mitral and/or aortic valves followed by a round of definitive echocardiography. Thus, they would have missed a large fraction of cases having valvular abnormalities like coexisting valve thickening without regurgitation during the screening round. This, we think, was an inadvertent methodological error.
In our experience, mitral valve prolapse is diagnosed in ≈1% to 4% of children screened for RHD by echocardiography.2,3 For mitral valve prolapse, significant regurgitation is a late feature, but it is not unusual to find thickened valves quite early in the course of disease. Thus, thickened valve leaflets in a child without significant regurgitation is more likely to be of nonrheumatic origin in our opinion. This fact is also corroborated by an autopsy study.4
In areas of low prevalence, the presentation of subclinical RHD may be different,2 and presentation and progression of the disease process leading to RHD in a given age group can be variable in different geographic areas because of differing environmental determinants.5 Consequently, the criteria proposed by Marijon et al may be important for the surveyed population of schoolchildren in Mozambique, but these criteria are difficult to adopt universally. If a diagnosis of RHD were to be based on the combined criteria proposed by Marijon et al, many cases with only significant regurgitation as evidence of disease would be missed. Such cases might be much greater in number as reported by Bhaya et al.2
Once acute rheumatic fever has been diagnosed, antibiotic therapy is offered to prevent recurrences, but it is unlikely that antibiotic therapy prevents the progression of the immune processes leading to RHD.6 The recent addition of statins to the possible options for pharmacotherapy of RHD necessitates that a diagnostic criterion for subclinical RHD should identify the patients in the state when significant regurgitation is due to softening of valves secondary to the disease process and well before the time when repeated rheumatic carditis results in chronicity of significant regurgitation due to scarring and retraction of leaflets.
We feel that focusing on significant regurgitation and not valve deformities would make echocardiographic criteria for diagnosis of subclinical RHD more sensitive and universally applicable.
Marijon E, Celermajer DS, Tafflet M, El-Haou S, Jani DN, Ferreira B, Mocumbi A, Paquet C, Sidi D, Jouven X. Rheumatic heart disease screening by echocardiography: the inadequacy of World Health Organization criteria for optimizing the diagnosis of subclinical disease. Circulation. 2009; 120: 663–668.