Clinical And Histopathologic Study Of Surgically Excised Mitral Valves In Children

摘要

The present study aims to interpret the histological changes observed in surgically excised mitral valves, and to how those changes relate to the clinical criteria of valve failure. A retrospective study was performed on 25 children patients with RHD, who had mitral valve surgery between 2000 and 2004 at the GOTHI hospitals. A highly significant association was present between absence of Aschoff nodules and atrial fibrillation (p=0.0070). Mitral calcification was significantly associated with atrial fibrillation (p=0.0050), followed by double mitral dysfunction (p=0.0142). Valvular endothelial ulcerations were significantly associated with mitral stenosis (p=0.0129) and double mitral dysfunction (p=0.0100). Rheumatic heart disease continues to be an important cardiac problem afflicting the young population of Egypt. The disease has a definite effect on mitral valve microanatomy. Clinical-pathologic correlation is important in evaluating the extent of valvular affection. Introduction Rheumatic fever is an acute, systemic, partly autoimmune disease triggered by a beta-hemolytic streptococcal throat infection that cross-reacts with human tissues and may stimulate or modify immunologic responses. It is characterized by a constellation of findings that include as major manifestations: migratory polyarthritis of the large joints, carditis, subcutaneous nodules, erythema marginatum of the skin, and Syndeham chorea; the latter is a neurological disorder with involuntary purposeless, rapid movements [1,2].Rheumatic heart disease (RHD) occurs in 30 to 45% patients with rheumatic fever (RF). The incidence of RF and RHD in the tropics remains high, with a high proportion of children suffering from carditis with the first episode. The prevalence of RHD in school-age children varies considerably throughout the world. It has been reported as 0.6/1000 in the USA and 0.7/1000 in Japan, while in developing countries the prevalence rates range from 0.3/1000 to 18.6/1000. In an Egyptian study by Refat and his colleagues, the prevalence of RHD in the primary school children was 3.4/1000 [3]. Approximately 20 million cases of rheumatic fever occur in third world countries annually, with a correspondingly high incidence of advanced mitral stenosis later in life. A genetic predisposition to develop RHD appears to be important in certain countries like India, Egypt and Turkey [4]. Chronic rheumatic heart disease is the most important consequence of rheumatic fever. It is characterized principally by deforming fibrotic valvular disease (particularly mitral stenosis), which can produce permanent dysfunction and severe, sometimes fatal, cardiac dysfunction decades later [5,6]. Clinical manifestations may not be seen for years after the initial episode of rheumatic fever. The signs and symptoms of valvular disease depend on which cardiac valve(s) is(are) involved. In addition to cardiac murmurs, cardiac hypertrophy and dilation, and heart failure, patients with chronic rheumatic heart disease may suffer from arrhythmias (particularly atrial fibrillation in the setting of mitral stenosis), thromboembolic complications, and infective endocarditis. Long-term prognosis is highly variable. There may be a relentless cycle of valvular deformity yielding hemodynamic abnormality, which begets further deforming fibrosis. In addition to affecting the cardiac valves, rheumatic heart disease is a pancarditis affecting to various degrees the endocardium, myocardium, and pericardium. In some cases, rheumatic myocarditis results in cardiac dilation and progressive heart failure [7].Mitral valve leaflets are the most common structures involved in rheumatic disease; typical pathological features of rheumatic mitral disease come from acute and recurrent inflammation [8]. The rheumatic process includes leaflet thickening, calcification and retraction, perianular calcification with limitation of annular motion, leaflet fusion, chordal thickening, shortening and fusion as well