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Chin Med J (Taipei) 1997;59:308-10.
Department of Surgery, Fuwai Heart Hospital, Peking Union Medical College, Beijing, P.R.C.
The association of secundum atrial septal defect (ASD) and congenital or acquired mitral lesions is rare. Only one case of secundum ASD and mitral lesion, in a three-year-old girl, has been encountered over a three-year period in this hospital. Diagnosis was not difficult with echocardiography, and was confirmed by operation. Surgical procedures including repair of ASD and annuloplasty of the mitral valve were performed under cardiopulmonary bypass. The mitral valve lesion was found during the operation to be of a congenital origin. Mitral lesions should not be neglected, and repair should be attempted even in a pediatric patient. Otherwise, anatomical and functional disorders of the mitral valve may develop at the early postoperative stage.
[Chin Med J (Taipei) 1997;59:308-10.]
Keywords: atrial septal defect, mitral valve lesion
Received: October 5, 1996.
Accepted: March 6, 1997.
Address reprint requests to: Shi-Min Yuan, Department of Surgery, Fuwai Heart Hospital, Peking Union Medical College, A 167, Fuwai Street, Beilishi Road, Xicheng District, Beijing, P.R.C.
The association of secundum atrial septal defect (ASD) and congenital or acquired mitral lesions is rare [1]. Patients with this syndrome are usually adults and older children [2,3]. Recently, a case of secundum ASD accompanied with mitral insufficiency (MI) was found in a three-year-old girl. Thus, an extensive review of the literature was undertaken in an attempt to assess the mechanism of MI.
A three-year-old girl had recurrent mild fever and cough, as well as a recognized heart murmur after birth. Chest X-ray showed enlargement of the right ventricle and pneumonia. The symptoms did not respond to antibiotic treatment The child was admitted to the Surgical Department of Fuwai Heart Hospital on May 2nd, 1995. On admission, her vital signs were normal. A grade 2/6 ejection systolic murmur could be heard over the 2nd intercostal space at the left upper sternal border and a grade 2/6 pansystolic murmur at the apex. An electrocardiogram showed sinus rhythm and right ventricular hypertrophy. An echocardiographic examination revealed enlargement of the pulmonary artery, left atrium and left ventricle. An ASD of 12 mm in diameter was also found in the center of the fossa ovalis. The anterior leaflet of the mitral valve prolapsed into the left ventricle during diastole.
The patient was operated on May 19th, 1995. After cardiopulmonary bypass was instituted, the heart was enlarged, and the pulmonary artery dilated with a high pulmonary artery pressure. Secundum ASD of a central type was 12 mm in diameter. The mitral annulus showed abnormal dilatation with the posterior leaflet prolongation and moderate prolapse. The mitral valve regurgitated severely by testing. A partial annular 2-0 polypropylene purse-string suture was inserted along the base of the posterior leaflet to foreshorten the annulus. The ASD was repaired with direct suture after the mitral annuloplasty. The heart resumed sinus rhythm spontaneously after cross-clamp removal. The pulmonary artery pressure decreased toward normal after the operation. She was discharged uneventfully on the seventh day postoperatively.
Mitral valve disease that complicates with left-to-right shunt at the atrial level is rare, but of great hemodynamic interest [4]. The first comprehensive description of the syndrome of mitral stenosis (MS) and ASD was published in 1916 by Lutembacher. Bashi and associates [4] suggested that the syndrome means a congenital defect in the atrial septum together with acquired rheumatic MS or MI. Nevertheless, many have considered that secundum ASD and mitral valvular lesions, irrespective of stenosis or insufficiency sharing the similar hemodynamic and surgical principles, should be attributed to Lutembacher syndrome [2].
Bashi et al reported that the incidence of MI among patients with ASD is 7.17% and the incidence of ASD in MI is 1.22%. Females predominated with a male-to-female ratio of 1:1.3. Their ages ranged from 7 to 69 years, with a mean of 23 years. But a pediatric case younger than seven years has not previously been reported [2-6].
With regard to the association of secundum ASD with MI, Pecock and associates [7] thought that the secundum type defect situated posteriorly and well away from the anterior positioned mitral valve. It thus seemed unlikely that the defect could directly affect either the anatomy or the function of the mitral valve, and it would appear that mild organic disease of the mitral leaflets or chordae was a separate entity. They also suggested that bacterial prophylaxis be advised when the diagnosis of mitral pathology was established. However, previous studies by Okada et al and Pomerance et al confirmed the coexistence of both fibrosis and myxomatous change in the same valve leaflet of the same patient. And it was suggested that valve thickening and fibrosis be secondary to the chronic hemodynamic stress related to the left-to-right shunt [8,9].
Mitral valve prolapse was a functional mechanism probably related to the peculiar left ventricular geometry or the ventricular volume [10]. Such prolapse was first described by Jeresaty [11] in 1971 as possibly related not to intrinsic abnormality, but to a small left ventricular volume. This observation was made in patients with hypertrophic cardiomyopathy, and the concept of prolapse as a functional phenomenon (secondary), as opposed to its being for a myxomatous valve (primary) was proposed. In 1975, a similar mechanism was suggested by Criley and Kissel [12] to occur in patients with ASD. Their explanation was that the relatively small ventricle, in the presence of a left-to-right shunt at atrial level, could induce mitral valve prolapse by systolic apposition of the subvalvular apparatus to the mitral valve ring. Of interest was another study that attributed attenuation or disappearance of echocardiographic mitral valve prolapse in patients following repair of ASD alone to altered postoperative left ventricular geometry [13]. Boucher and associates also suggested that the etiology of MI in association with ASD might be different from that of classic isolated mitral valve prolapse. Despite a reported high incidence of mitral valve prolapse in ASD, clinically significant MI was generally found in the older patients. These mitral valves were usually thick and fibrotic, suggesting either a rheumatic or chronic degenerative process rather than the anticipated progressive billowing and attenuation involved in classic valve prolapse [6]. On the other hand, Joy and associates [5] proved, by macro- and microscopic studies on mitral lesions of 50 patients associated with secundum ASD, that MS was commonly a sequela of mitral valvulitis, and that some patients with isolated MI or mitral prolapse also have post-inflammatory lesions in the valve. Mitral valve prolapse could thus also be a result of a chronic rheumatic process.
In view of the young age (three years) and the operative findings of the present case, MI should be of congenital origin in this particular case. Regardless of the mechanism involved, surgical correction of MI in association of ASD in this young age group still poses some technical difficulties. Although mitral annuloplasty was performed for this particular patient, long-term follow-up is needed to assess the result of the present repair.
Copyright: 1997, Chinese Medical Association (Taipei)