Журнал «Здоровье ребенка» 1 (52) 2014

Introduction

Prevalenceof mitral valve prolapse  (MVP) in children's age according to researchers makes up from 2,4 % to 14 %. In such patients  in progressing  MVP, developmentand increase in frequency of such dangerous complications asinfectious endocarditis, cardiac dysrythmia thromboembolism, ischemic stroke, sudden death, formation of chronic mitral in sufficiency  are  possible with age, all mentioned demands long treatment and supervision.

The most informativein diagnostics of MVP is echocardiography method. Despite improvement of echocardiographic diagnostic criteria, now there are no uniform recommendations on classification and definition of MVP origin. Considering ambiguity inprognosis of MVP course depending onitsetiology, possibility of development of life-threatening complications, formationsof chronic cardiac insufficiency, it is expedient and timelyto search  forfurther diagnostic criteria of different etiopathogenetic variants of MVP origin in children.

Materials and methods

With the purpose to determine  hemodynamic and morphometric features of MVP of inflammatoryand non-inflammatory  genesis in children by the data of doppler-echocardiography (DopplerEchoCG) the analysisof 34 cases of  clinical course of MVPin childrenat the age from 5 till 17 yearsis carried out. For  comparative analysis 2 groupsof children were distinguished: the first group – 16 children with MVP of non-inflammatory  genesis, the second one – 18 children with MVP of inflammatory genesis.

Criteria of inclusionin the 1-st group were: child’s age of more than 5 years, existence of stigmas of non-differentiated dysplasia of connective tissue, absence of congenitalheart disease, lack of a carditis in the anamnesis, absence of echocardiographic (EchoCG) signs of endo- and myocarditis. Criteriaof inclusionin the 2-nd group were: infectious myocarditis in the anamnesis, existence of EchoCG  signs of inflammatory lesionof  myocardium, absence of congenital heart disease.

Morphometricindicators of heart, parameters of intracardiac hemodynamics were measured with the help one - and two-dimensional EchoCG, impulseDopplerEchoCG on the ultrasonic scanner by a standard technique. Determination of ultrasonic density of the mitral valve and subvalvular structures was carried out by means of measurements of ratio of ultrasonic density in standard zones (valve ring,  edge of septal cusp) during digital computer processing of echocardiograms.

Results

In the analysisof EchoCG indicators in children with MVP some distinctions in groups were revealed. Averagesizes of diameter of the left ventricle, the leftauricleand the right ventricle which were normalized by the body area, had no essential distinctions in the groups (p > 0,05). Thus, in childrenof the 2nd group  frequency of cases of increase of the left ventricle cavity (6,3 % and 16,7 %, p > 0,05), was bigger and the increase of the right ventricle cavity – essentially bigger (37,5 % and 61,1 % respectively, p < 0,05) this was explained by existence of chronictonsillitis in children. In children of the 2nd group the increase in thickness of posterior wall of the leftventricle, interventricular septumrelativelythe norm (31,2 % and 61,1 %, 56,3 % and 94,4 % respectively, p < 0,01) was revealed more often. In children of the 2ndgroupmassof myocardiumof the leftventricle on average was authentically bigger (p < 0,01), this testified to  hypertrophy of myocardium which was revealed in 61 % of cases.  Myocardial contractivity with the same frequency was loweredin the 1-st (31,3 %) and the 2nd (22,2 %) groups of children though this did not influence indicators of the central hemodynamics. Children with MVP in bothgroups in 93,8 % and 100 % of cases had transmitral regurgitation of different degree. In children of the 2nd group MVP was accompanied with regurgitation of the ІІІ degree reliably more often. (83,3 % and 37,5 % of cases, p < 0,001). Less considerable regurgitation (І–ІІ degrees) which was hemodynamically not significant was observedmore often in the 1st group of children. It was revealedbigger frequency of  tricuspid regurgitation of the ІІІ degreein children of the 1-st group (19 %), this was explained by the existence  of  syndrome of connective tissue dysplasiain allcases. In such children regurgitation was registered simultaneously on mitraland tricuspid valves.

Normal ultrasonic density of the mitral valve cusps authentically more often was revealedin children of the 1st group: anterior cusp – in 37,5 % against 11,1 % of cases in the 2nd group (p < 0,01); posterior cusp - in 62,5 % against 22,1 % of casesinthe 2nd group (p < 0,01).

Increaseof ratio of ultrasonic densityof both cusps of the mitral valvein the zone of  mitral ring was revealed in 37,5 % of children of the 1st group and in 50 % of children of the 2nd group, thus childrenof the 2nd group in 55,5 % of cases hada considerable increase of ultrasonic density. Similar deviations of ultrasonic density were revealedand from the side of edge of anterior and posterior cusps of the valve. In both groups of children increase of ultrasonic density of anterior cusp of the mitral valve (76,9 % and 86,7 % of cases, respectively) prevailed. In children with MVP of inflammatory genesis in prevailing number of cases  increase of ultrasonic density of anterior - 83,3 % and posterior - 94,4 % of papillary muscle of the left ventricle, in the main of considerable and sharp degree (76,5 %),was revealed; this was regarded as a symptom of the suffered myocarditis.

The thickeningof anterior cusp of the mitral valvemore than the norm (more than 3 mm) was revealed reliably more often in childrenof the 2nd group - 72,2 % and 50 %, correspondingly (p < 0,05). Authentically less often in bothgroups thickening of posterior cusp of the mitral valve was revealed (p < 0,05), thus the percent of cases of thickeningof posterior cuspin groups wasapproximately  the same: 31,3 % in the 1st group and 44,4 % - in the 2nd group (p > 0,05).

Conclusions

The carried-out researches made it possible to reveal characteristics of MVPof inflammatory genesis which canbe obtained by means of EcoCG examination. In children with a prolapse of the mitral valve of inflammatory genesis authentically more often thickeningof myocardium wall and myocardium mass were revealed, this testified to hypertrophy of the left ventricle; more often prolapse of ІІ–ІІІ degrees  was revealed; authentically more often mitral regurgitation of ІІІ degreleading to development of chronic  cardiac  insufficiency  was noted. In 83,3–94,4 % of cases substantial or sharp increase of ultrasonic density of papillary muscles of the left ventricle was revealed, this was not characteristicfor a prolapse of non-inflammatory genesis. In all children with a prolapse of the mitral valve increaseof ultrasonic density of anterior cusp prevailed. The thickening of anterior cusp bymore than 3 mm authentically more often was observed in children with  prolapse of the mitral valve of inflammatory genesis.