Supravalvular Stenosing Ring of the Left Atrium Jorge Oglietti, M.D., George J. Reul, Jr., M.D., Robert D. Leachman, M.D., a n d Denton A. Cooley, M.D. ABSTRACT 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.

Congenital obstruction of left atrial flow can be caused by several malformations that originate at or proximal to the mitral valve, i.e., pulmonary vein stenosis, cor triatriatum, supravalvular stenosing ring, or mitral stenosis. Since all these disorders are reflected in pulmonary and right ventricular hypertension, a definite diagnosis can be made only with the aid of cardiac catheterization, angiography, and echocardiography. Supravalvular stenosing ring of the left atrium is a rare malformation frequently associated with other cardiac defects and often eludes the most astute diagnostician. Since Fisher [6] in 1902 described the first case of supravalvular stenosing ring of the left atrium, only 24 patients have appeared in the literature. Chung and associates [5] recently reFrom the Divisions of Surgery and Cardiology, Texas Heart Institute of St. Luke’s Episcopal and Texas Children’s Hospitals, Houston, TX. Accepted for publication Sept 16, 1975. Address reprint requests to Dr. Cooley, Texas Heart Institute, PO Box 20345, Houston, TX 77025. 421

ported the first isolated case that has been treated successfully. The association of this anomaly with tetralogy of Fallot has been described only once before [8]. In patients with supravalvular stenosing ring, the mitral valve is anatomically normal but the mitral inlet is encroached upon by a circumferential supravalvular ridge, or membrane, with one or two narrow orifices that arise from the base of the atrial aspect of the mitral leaflets (Fig 1). This defect may be part of a developmental complex of four obstructive lesions in series: supravalvular stenosing ring of the left atrium, parachute mitral valve, subaortic stenosis, and coarctation of the aorta [17]. The fact that the anomaly can be corrected surgically with minimal effort undoubtedly has stimulated increased attention to its recognition. This report presents 2 patients with supravalvular stenosing ring, 1 of whom had an associated ventricular septal defect and WolffParkinson-White syndrome and the other, tetralogy of Fallot. The purpose of this paper is to point out the hazards of not recognizing and diagnosing this anomaly when associated with other congenital cardiac defects. Case Reports

Patient 1 (This patient was previously reported by Rosenberg and associates [15].) A 9-year-old girl was admitted to Texas Children’s Hospital on February 14, 1969, with a history of cardiac murmur present since birth, cyanosis, recurrent respiratory infections, several episodes of congestive heart failure, and frequent episodes of paroxysmal atrial tachycardia that were not amenable to control with digitalis or propranolol. Physical examination revealed a poorly developed, cyanotic child with clubbing, tachycardia, and tachypnea who was in severe distress due to congestive heart failure. Her temperature was 38.9”C, pulse 200 per minute, respiratory rate 60 per minute, and blood pressure 110/70 mm Hg. She weighed 28.5 kg and

422 The Annals of Thoracic Surgery Vol 21 No 5 May 1976

A

~

B

Fig I . Anatomical differences between supravalvular stenosing ring and cor triatriatum. ( A )Cor triatriatum. The diaphragm partitions the left atrium into a dorsal chamber that receives the pulmonary veins and a ventral chamber(true left atrium) that gives rise to the left atrial appendage and leads to the mitral valve. ( B ) Supravalvular stenosing ring. The inlet of the normal mitral valve is encroached upon by a circumferential ridge or membrane. The left atrial appendage lies above the membrane.

measured 145 cm. The chest was symmetrical bilaterally and there were moist rales in both lungs. Examination of the heart revealed a prominent systolic murmur over the precordium; however, because of recurrent episodes of atrial tachycardia during her hospitalization, it was almost impossible to evaluate clearly the presence of diastolic murmurs. The second heart sound was single at a rapid rate. The liver was palpable four finger-breadths below the right costal margin and was tender. The peripheral pulses were normal, and she had no edema. Laboratory data were unremarkable. The electrocardiogram at different times showed patterns of Wolff-Parkinson- White syndrome, left bundle-branch block, paroxysmal atrial tachycardia, right axis deviation, biatrial enlargement, and right ventricular hypertrophy. The chest roentgenogram showed notable cardiomegaly with increased pulmonary vascular markings. Three attempts to convert the paroxysmal atrial tachycardia by direct-current countershock were unsuccessful. One day after admission the heart rate spontaneously decreased to 120 per minute, and she underwent cardiac catheterization, which revealed a large ventricular septal defect with right-to-left shunt, severe pulmonary hypertension, and an anomalous mitral

valve. Right ventricular pressure was 75/10 mm Hg, main pulmonary artery pressure 75/45, and pulmonary wedge pressure 30111. Systemic oxygen saturation was 70%. Angiography failed to reveal the presence of the accessory left atrial membrane. Surgical correction was attempted on February 16,1969. The thorax was entered through a median sternotomy incision. Left atriotomy was performed posterior to the interatrial groove, and the supravalvular stenotic ring, which consisted of a dense fibrotic ring that barely admitted a fingertip, was excised. The mitral valve appeared normal. The ventricular septal defect was approached through a right ventriculotomy and closed with a Dacron patch. The patient was weaned from cardiopulmonary bypass with some difficulty, and pacing wires were inserted in the right atrium to obviate postoperative rhythm disturbances. The child tolerated the operation well and was sent to the recovery room in satisfactory condition. The postoperative course was complicated by recurrent episodes of supraventricular tachycardia, bilateral bronchopneumonia and hemoptysis, and hemorrhagic pleural effusion attributed to pulmonary emboli. Satisfactory control of the respiratory distress and infection could not be achieved, and she died 34 days after operation. At postmortem examination a large thrombus, well organized and partially recanalized, was found in the superior vena cava. Multiple thromboemboli were discovered in the pulmonary arteries bilaterally with localized pulmonary infarctions. An anomalous anterior papillary muscle of the tricuspid valve with an anomalous atrioventricular myocardial com-

423 Oglietti et al: Supravalvular Stenosing Ring of the Left Atrium

valvectomy, infundibulectomy, and ventriculoplasty of the outflow tract using a Dacron patch. After a complicated postoperative course, the patient died on the sixth day after operation in severe pulmonary edema. Mitral stenosis, the more logical explanation for the severe low cardiac output syndrome, was not suspected .because of the extreme rarity of the association of the tetralogy complex and supravalvular mitral stenosis. A circular, diaphragmlike structure with an orifice 12 mm in diameter was found postmortem. The mitral valve was normal. Fig2. (Patient 1 . ) Microscopical study of the supravalvular ring, showing a dense layer of sclerotic tissue resembling valve substance but without the discrete layers of a valve. O n l y a fezu muscle fibers are present in the depths of the specimen, zuhich differentiates this membrane from the bilnrninnr rnuscular structure of coy triatriatum. (H0. E ; original magnification X52.)

Comment Supravalvular stenosing ring is a rare congenital malformation of the heart characterized by an abnormal diaphragm that divides the left atrium into two separate chambers. As this membrane arises at the base of the atrial aspect of the mitral valve, the dorsal chamber receives the pulmomunication was found, confirming the clinical nary veins and connects with the left atrial apdiagnosis of Wolff-Parkinson-W hite syndrome. pendage, which differentiates this entity from Microscopical study of the supravalvular ring cor triatriatum (see Fig 1).The ventral chamber, showed a dense layer of sclerotic tissue resem- very small in size, leads to the mitral valve, bling valve substance but without the discrete which is usually normal. The membrane may be layers of a valve. Instead there was a broad, attached closely to the mitral valve. One or two loosely arranged connective tissue layer along small orifices connect both chambers. Hence, most of the structure with an area of fibroblastic the hemodynamic abnormality is similar to that proliferation on the opposite edge. A few muscle of mitral stenosis. fibers were present in the depths of the speciFisher [61 in 1902 was the first to describe this men, and there were several small blood vessels rare occurrence, and Lynch and associates [113 along one edge (Fig 2). performed successful surgical correction in 1962. Several patients have since been reported [l, 3, Patient 2 4, 9, 13, 16, 181. Only in the patient successfully This patient, the second of 2 found in the litera- treated by Chung and colleagues [51 was the ture with supravalvular stenosing ring as- lesion isolated. The rare association of this anomsociated with tetralogy of Fallot, has been re- aly with tetralogy of Fallot in the only 2 such ported previously from this institution [2]. He cases reported contributed to the death of both was a 25-year-old man with typical signs and patients. The hypothesis put forth by Rogers symptoms of tetralogy of Fallot in whom the and co-workers [14] of acquired jet lesion from diagnosis of supravalvular stenotic ring was not mitral insufficiency accompanying left ventricumade. This diagnostic oversight contributed to lar endocardiosclerosis has been abandoned. It his death. The foramen ovale was closed; thus seems more logical to accept the congenital orionly right heart catheterization was performed. gin described by Manubens, Krovetz, and Results of all studies provided no evidence of Adams: "It seems unlikely that a regurgitant mitral stenosis-even the exceptionally slow localized jet of blood can produce a smoothpulmonary flow was attributed to the severe out- edged symmetrical ring" [12]. The ring is a strucflow tract obstruction of the right ventricle. ture of sclerotic material resembling the valve On November 5, 1973, correction was per- substance but without the discrete layers of a formed consisting of closure of the ventricular valve (see Fig 2). This also differentiates supsepta1 defect with a Dacron patch, pulmonary ravalvular stenotic ring from cor triatriatum, in

424 The Annals of Thoracic Surgery Vol 21 No 5 May 1976

which the membrane is a bilaminar muscular structure (striated and smooth). The clinical picture depends upon the degree of obstruction to the pulmonary venous flow in rare cases of isolated stenosing ring; the picture is often masked by the frequently associated anomalies in other patients. The functional consequences are essentially analogous to those of mitral stenosis with elevated pulmonary venous and arterial pressure. Infants with severe obstruction experience signs of congestive heart failure, irritability, difficulty in feeding, and failure to thrive. In older children and adults, chronic effort dyspnea may precede episodes of frank pulmonary edema, which appears to account in part for the frequently reported histories of respiratory infections. Chest roentgenograms may present a “ground-glass” appearance related to dilatation of the pulmonary veins. Unlike cor triatriatum, in supravalvular stenosing ring the left atrium and left atrial appendage are enlarged. When there are neither roentgenographic nor electrocardiographic signs of left ventricular hypertrophy, roentgenographic signs of pulmonary venous obstruction should suggest obstruction of flow at or proximal to the mitral valve [71. The electrocardiogram usually shows right axis deviation withvarying degrees of biatrial enlargement and right ventricular hypertrophy. Supravalvular stenosing ring can exist with no murmurs being heard. The second sound is increased and usually is not split. Unlike cor triatriatum, cardiac catheterization in supravalvular stenosing ring reveals a high left atrial pressure. The angiogram only occasionally shows the membrane. Injection of contrast material into the main pulmonary artery to demonstrate the left atrial anatomy is the diagnostic procedure of choice for patients with cor triatriatum or stenosing ring. Echocardiography has potential value in the diagnosis of these two membranous malformations of the left atrium [lo]. An absolute diagnosis cannot be made clinically and often can be made only by surgical exploration.

References 1. Anabtawi I, Ellison RG: Congenital stenosing ring of the left atrioventricular canal (supravalvu-

lar mitral stenosis). J Thorac Cardiovasc Surg 49:994, 1965 2. Benrey J, Leachman RD, Cooley DA, et al: Supravalvular mitral stenosis associated with tetralogy of Fallot. Am J Cardiol 37:111, 1976 3. Cassano G: Congenital annular stenosis of the left atrioventricular canal. Am J Cardiol 13:708, 1964 4. Cheder E, Beck W, Barnard CN, et al: Supravalvular stenosing ring of the left atrium associated with corrected transposition of the great vessels. Am J Cardiol 31234, 1973 5. Chung KJ, Manning JA, Lipchik EO, et al: Isolated supravalvular stenosing ring of left atrium: diagnosis before operation and successful surgical treatment. Chest 65:25, 1974 6. Fisher T: Two cases of congenital disease of the left side of the heart. Br Med J 1:639, 1902 7. Grondin C, Leonard AS, Anderson RC, et al: Cor triatriatum: a diagnostic surgical enigma. J Thorac Cardiovasc Surg 48:527, 1964 8. Hohn AR, Jain KK, Tamer DM: Supravalvular mitral stenosis in a patient with tetralogy of Fallot. Am J Cardiol 22:733, 1968 9. Johnson NJ, Dodd K: Obstruction to left atrial outflow by a supravalvular stenosing ring. J Pediatr 51:190, 1957 10. Lundstrom NR: Ultrasoundcardiographic studies of the mitral valve region in young infants with mitral atresia, mitral stenosis, hypoplasia of the left ventricle, and cor triatriatum. Circulation 45:324, 1972 11. Lynch MF, Ryan NJ, Williams GR, et al: Preoperative diagnosis and surgical correction of supravalvular mitral stenosis and ventricular septa1 defect. Circulation 25:854, 1962 12. ManubensR, Krovetz LJ, Adams P Jr: Supravalvular stenosing ring of the left atrium. Am Heart J 60:286, 1960 13. Mehrizi A, Hutchins GM, Wilson EF, et al: Supravalvular mitral stenosis. J Pediatr 6:7:1141,1965 14. Rogers HM, Waldron BR, Murphey DFH, et al: Supravalvular stenosing ring of left atrium in association with endocardial sclerosis (endocardial fibroelastosis) and mitral insufficiency. Am Heart J 50:777, 1955 15. Rosenberg HS, Klima T, McNamara DG, et al: Atrioventricular communication in the WolffParkinson-White syndrome. Am J Clin Pathol 56:79, 1971 16. Satyanarayana R, Anderson RC, Lucas RV, et al: Clinical pathologic conference. Am Heart J 77:538, 1969 17. Shone JD, Sellers RD, Anderson RC, et al: The developmental complex of ”parachute mitral valve,” supravalvular ring of the left atrium, subaortic stenosis and coarctation of the aorta. Am J Cardiol 11:714, 1963 18. Stretton TB, Fentem PH: Stenosis of the left atrio-ventricular canal. Br Heart J 24:237, 1962

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-P...
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