Supravalvular stenosing ring of left atrium in association with endocardial sclerosis (endocardial fibroelastosis) and mitral insufficiency

Echocardiographic characteristics of annulo-leaflet mitral ring

BACKGROUND

Annulo-leaflet mitral ring (ALMR) is a rare congenital cardiac anomaly caused by fibrous tissue on the atrial surface of the mitral valve, which can progress to cause severe stenosis. Because little information is available on the detailed echocardiographic features of the anomaly and their associations with surgical resection, this study was undertaken to address these questions.

METHODS

A retrospective single-center study of clinical and echocardiographic data from patients with ALMR from 2004 through 2012 was conducted. Data were analyzed for associations with surgical resection.

RESULTS

The median age at diagnosis of the 57 study patients was 1.8 years, and 63% were male. Isolated ALMR was found in six patients (11%). The remaining 51 patients (89%) had associated lesions: additional mitral valve abnormalities in 35 (61%), coarctation in 11 (19%), and subaortic stenosis in 15 (26%). ALMR was best visualized in the apical four-chamber view, and the lesion was indistinct from the parasternal long-axis view in 25% of patients. Seven patterns of ALMR were identified, differentiated by leaflet involvement (anterior, posterior, or both) and location (annular vs intraleaflet). Compared with other patterns, intraleaflet morphology had a higher mean mitral stenosis gradient than in patients without (8.4 vs 5.8 mm Hg, P = .01). Among the 57 patients, 32 (56%) underwent ALMR resection, at a median age of 1.5 years. Younger age at echocardiographic diagnosis (P = .02) and short chordae (P = .03) were associated with resection.

CONCLUSIONS

The morphology of ALMR as evaluated by echocardiography is heterogeneous and can be classified on the basis of lesion location and leaflet involvement. Intraleaflet morphology is associated with significant mitral stenosis; younger age at diagnosis and short chordae are associated with ALMR resection.

Cor triatriatum with mitral regurgitation in a 52-year-old male

The clinical, echocardiographic, and cineangiographic features of the oldest known living case of cor triatriatum are presented. Mitral regurgitation, also found in this patient, has been reported on only two previous occasions to coexist with other wise uncomplicated cor triatriatum. The value of two-dimensional echocardiography in the identification of this congenital anomaly is confirmed.

Echocardiographic features of congenital left ventricular inflow obstruction

The echocardiographic features of congenital left ventricular inflow obstruction are described in six patients. The echocardiograms in two patients with cor triatriatum were distinguished by normal mitral valve motion and an abnormal echo within the left atrium. In two patients with supravalvar mitral ring, in addition to abnormal mitral valve motion, an abnormal echo, presumably originating from the obstructive membrane, was located between the anterior and posterior mitral leaflets. In two cases of parachute mitral valve, mitral valve motion was abnormal. In one of these cases there were multiple mitral valve echoes similar to those found in supravalvar mitral ring. The echocardiographic identification of an obstructive membrane within the left atrium is difficult because of the occurrence of artifacts. However, membranes may be identified if careful scanning techniques are employed in patients in whom left ventricular inflow obstruction is suspected. The echocardiogram is useful in detecting mitral valve abnormalities in these patients and is valuable in cases where mitral valve replacement is contemplated.

Supravalvular stenosing ring of the left atrium

Two patients with supravalvular stenosing ring of the left atrium are described. In 1 patient with an associated ventricular septal defect and Wolff-Parkinson-White syndrome, the diagnosis of supravalvular stenosing ring was only suspected. This patient underwent correction but died 34 days after the operation because of pulmonary embolism. In the second patient a preoperative diagnosis was not made, and this contributed to his death following correction of tetralogy of Fallot. The association of these two anomalies is very rare. Differential diagnosis from other congenital anomalies producing obstruction of left atrial flow is discussed. The divergent microscopical features of the membrane in supravalvular stenosing ring of the left atrium and in cor triatriatum are described. The value of cardiac catheterization, angiography, and echocardiography as diagnostic aids is emphasized. The hazards of not recognizing and diagnosing this anomaly when associated with other cardiac malformations are pointed out.

Diagnosis and management of parachute mitral valve and supravalvar mitral ring

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Diseases of the mitral valve in infancy. An anatomic analysis of 55 cases

A pathologic study of mitral valvular lesions among 55 infants revealed 29 cases in which the mitral valve was the site of a primary congenital malformation and 26 cases in which the mitral lesion was an acquired infarction of papillary muscles secondary to some other malformation.

Among the 29 cases with primary congenital anomalies of the mitral valve, there were 41 lesions represented. Congenital anomalies were identified according to the four components of the valve as follows: leaflets, commissures, chordae tendineae, and papillary muscles. The most common basis for primary congenital mitral valvular disturbance was an abnormality of the papillary muscles. In this group, parachute mitral valve and abnormal position of papillary muscles associated with endocardial fibroelastosis were most common (eight and 10 examples, respectively). Anomalous mitral arcade and obstructing papillary muscles were observed four and three times, respectively.

Involvement of leaflets was the second most common type of congenital anomaly, being observed 11 times. In this group, in order of decreasing frequency, were supra-valvular ring (five cases), accessory mitral valvular tissue (three cases), "Ebstein's" malformation of the left atrioventricular valve in corrected transposition (two cases), and cleft mitral valve (one case).

Commissural fusion was observed once and, in two cases, involvement of multiple components of the valve was observed.

Among the 26 examples of infarction of papillary muscles, exclusive of 10 cases with endocardial fibroelastosis, the fundamental congenital anomalies included aortic stenosis (15 cases), coarctation of the aorta (six cases), and anomalous origin of the left coronary artery from the pulmonary trunk (five cases).

Subvalvar congenital mitral stenosis

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Preoperative Diagnosis and Surgical Correction of Supravalvular Mitral Stenosis and Ventricular Septal Defect

A child with supravalvular mitral stenosis plus ventricular septal defect is reported in whom the correct diagnosis was suspected clinically, confirmed by cardiac catheterization, and successfully treated surgically. Only eight previous cases of supravalvular mitral stenosis have been reported; five of the eight have had associated ventricular septal defects. None was correctly diagnosed before autopsy or surgery.

Our patient had a murmur and thrill characteristic of a ventricular septal defect. The pertinent clinical findings suggesting concomitant mitral stenosis consisted of a mitral mid-diastolic murmur that was unusually loud for the magnitude of the left-to-right shunt; a presystolic component to the diastolic murmur; marked left atrial enlargement by x-ray with only moderate pulmonary plethora; and electrocardiographic evidence of left atrial hypertrophy and marked pure right ventricular hypertrophy. Right heart catheterization showed labile passive pulmonary hypertension. Left atrial puncture revealed high proximal and low distal pressure.

Surgical correction of both lesions by total cardiac bypass was accomplished through a midline sternal-splitting incision. The supravalvular mitral membrane was excised from the right atrium through an incision in the atrial septum.