Development Of Subaortic Stenosis Research Articles

Subaortic Area at Risk for Development of Obstruction After Surgical Repair of Atrioventricular Septal Defect: Myth or Reality?

Morphology of the left ventricular outflow tract (LVOT) in atrioventricular septal defects (AVSDs) has been reported to be at risk for development of obstruction. The purpose of the present study was to identify the incidence, the risk factors, and the surgical outcomes of subaortic stenosis in repaired AVSDs. Records of 427 consecutive patients who underwent anatomical repair for all types of AVSDs from January 2000 to December 2012 were reviewed. Outcomes, independent risk factors, reoperation, and death were analyzed. In a median follow-up of five years (range: 17 months-11.8 years), eight patients required nine reoperations for subaortic stenosis. Study group (n = 11) included three additional patients for whom repair was performed in a different institution. Median delay for reoperation was 11.9 years (range: 1.3-19.4 years). Surgical relief of subaortic stenosis was obtained by means of the enlargement of the LVOT: resection of fibrous structures in all reoperated patients and associated with septal myectomy in four. Two patients required a modified Konno procedure. Five reoperations were associated with left atrioventricular valve repair or replacement. Statistical analysis didn't reveal any morphologic or demographic risk factors. No early or late death occurred. The development of subaortic stenosis after repair of AVSD remains a rare complication in midterm follow-up (incidence: 1.9%). The performance of preventive gesture during repair seemed to be unjustified. The surgical management of this reoperation consists of a simple and safe procedure.

Echocardiographic Predictors for the Development of Subaortic Stenosis After Repair of Atrioventricular Septal Defect

Echocardiographic Predictors for the Development of Subaortic Stenosis After Repair of Atrioventricular Septal Defect

Pulmonary artery banding and ventricular septal defect enlargement in patients with univentricular atrioventricular connection and the aorta originating from an incomplete ventricle.

In patients with univentricular atrioventricular connection and the aorta originating from an incomplete ventricle, subaortic stenosis is generally due to a restrictive ventricular septal defect (RVSD), that may be present at birth or develop after palliative procedures. In particular, a primary role in the genesis of the RVSD has been ascribed to pulmonary artery banding (PAB). The aim of this paper is to analyse the possible risk factors for the development of an RVSD, including PAB, and the results of one of the proposed procedures for treatment of this condition (RVSD enlargement). We retrospectively reviewed clinical records and outpatient records of 24 consecutive patients with univentricular atrioventricular connection and the aorta originating from the incomplete ventricle that received their first treatment at our institution from January 1991 to April 2000. The variables age, sex, weight, diagnosis, surgical procedures, associated anomalies, associated surgical procedures, were considered. Four patients (16.7%) had absent left atrioventricular connection, seven (29.7%) had absent right atrioventricular connection and discordant ventriculo-arterial connection, and 13 (54.7%) had double inlet left ventricle and discordant ventriculo-arterial connection. Five patients (20.8%) had associated coarctation or hypoplasia of the aorta, and eight (33.3%) had pulmonary stenosis or atresia. Median age at the first operation was 7.5 days (range: 1-376). Median weight was 3.5 kg (range: 1.9-6.3). Seventeen patients underwent pulmonary artery banding, one underwent a Damus-Kaye-Stansel connection, one received a Glenn shunt and five a modified Blalock-Taussig shunt. Early mortality was 12.5%. The only variable associated with operative mortality was the presence of coarctation or hypoplasia of the aorta (P=0.004). Ten patients (41.6%) developed subaortic stenosis. None of the tested variables, including pulmonary artery banding, was associated with the development of subaortic stenosis. Subaortic stenosis was due to a restrictive VSD in eight patients, six of whom underwent direct VSD enlargement by muscular resection and are well at last follow-up (four complete repairs). None of the procedures was complicated by complete heart block. In two cases subaortic stenosis was treated by a Damus-Kaye-Stansel connection. A single patient died during follow-up, and 11 patients have achieved a complete one-ventricle repair. In our experience, pulmonary artery banding was not associated with an increased risk of developing an RVSD. VSD enlargement proved to be safe and effective for treatment of subaortic stenosis due to an RVSD.

Echocardiographic predictors for the development of subaortic stenosis after atrioventricular septal defect repair Scott Lim, Greg Ensing, Stephen Mooradian, Achiau Ludomirsky, Albert Rocchini. University of Michigan, Ann Arbor, MI

Echocardiographic predictors for the development of subaortic stenosis after atrioventricular septal defect repair Scott Lim, Greg Ensing, Stephen Mooradian, Achiau Ludomirsky, Albert Rocchini. University of Michigan, Ann Arbor, MI

Development of a Noninvasive Marker of Wall Shear Stress Effects in Discrete Subaortic Stenosis

The precise etiology of discrete subaortic stenosis is unknown. It has been suggested that shear forces play a role in its initiation and progression. Because shear stress and its derivatives cannot be directly measured in vivo, we designed this study to define a clinical index of the wall shear stress and its spatial derivative using Doppler echocardiography. Using a computational model, we tested the hypothesis that a modification of the Dean number, a dimensionless index that describes shear rates in curved vessels, may yield a correlate of shear stresses in the region of interest. This would enable verification of our proposed etiology and may yield a noninvasive method to predict the development of subaortic stenosis. With the results from the computational model, we determined an index based on modifications to the Dean number that linearly correlates with the magnitude and the spatial derivative of shear stress.

Systemic obstruction in univentricular hearts: Surgical options for neonates

The surgical management for bridging patients with univentricular heart and systemic obstruction to a Fontan procedure remains controversial. Twenty-seven of 96 patients with univentricular heart and unobstructed pulmonary blood flow referred for surgical palliation were seen with systemic obstruction. Twenty-six were neonates with coarctation of the aorta in 21 and subaortic stenosis in 5. In 8 other patients, subaortic stenosis developed after initial pulmonary artery banding. Four different palliative procedures were performed: coarctation repair with pulmonary artery banding (group I, n = 15); Norwood or Damus-Kaye-Stansel or arterial switch operation (group II, n = 9); coarctation repair with pulmonary artery banding and bulboventricular foramen enlargement (group III, n = 2); and orthotopic heart transplantation with coarctation repair (group IV, n = 1). The mortality rate was 34.3% (n = 12) for all patients, 53.3% in group I, 33.3% in group II (p = 0.003 versus group I), and 50% in group III. Nine patients (8 in group I and 1 in group II) had development of subaortic stenosis and underwent a subsequent procedure: Damus-Kaye-Stansel operation in 5, arterial switch operation in 3, and bulboventricular foramen enlargement in 1. Three had a concomitant or subsequent Fontan procedure and 2, a bidirectional Glenn procedure. In group II, 1 patient underwent a subsequent Fontan procedure and another, a bidirectional Glenn anastomosis. Six of the 8 patients with subaortic stenosis after initial pulmonary artery banding underwent a second stage consisting of a Damus-Kaye-Stansel procedure (n = 3), bulboventricular foramen enlargement (n = 2), or creation of an aortopulmonary window (n = 1). Three had a concomitant Fontan procedure and 2, a bidirectional Glenn procedure. Actuarial 4-year survival was 65.5% +/- 8.4% (70% confidence limits) for all patients; it was 40% +/- 13.3% in group I and 66.6% +/- 16.3% in group II (p < 0.05). Initial management of patients with univentricular heart and systemic obstruction by Norwood-like procedures provides a better outcome. Success of the Fontan operation relies on the ability to provide timely relief of subaortic stenosis.

Early changes in ventricular septal defect size and ventricular geometry in the single left ventricle after volume-unloading surgery

This study investigated the phenomenon of, and the relation between, alterations in ventricular geometry after acute surgical volume unloading of the ventricle and the development of subaortic stenosis in patients with a single ventricle and ventricular septal defect-dependent systemic flow. Subaortic outflow obstruction has been observed to occur in patients with a single left ventricle after placement of a pulmonary artery band. The timing and etiology of this phenomenon are not well defined. The preoperative and postoperative echocardiograms of 18 patients 14.9 +/- 22.8 months old (mean +/- SD) with a diagnosis of single left ventricle who underwent pulmonary artery banding or cavopulmonary connection were reviewed. Postoperative studies were performed a mean of 7.0 +/- 6.5 days after operation. The ventricular septal defect diameter was measured in two orthogonal views and the area calculated using the formula for an ellipse. Interventricular septal and posterior wall thickness and left ventricular diameter and length were also measured. Mean ventricular septal defect area indexed to body surface area diminished by 36 +/- 23% (3.1 +/- 2.7 to 2.0 +/- 1.8 cm2/m2, p < 0.01). Mean interventricular septal and posterior wall thickness increased significantly, and left ventricular diameter and length decreased significantly. A greater diminution in ventricular septal defect area was noted after cavopulmonary connection (41 +/- 19%, p < 0.01) than after pulmonary artery banding (25 +/- 28%, p = 0.22). In the single left ventricle, diminution in ventricular septal defect size occurs early and is related to an acute alteration in ventricular geometry that accompanies the decrease in ventricular volume. Ventricular septal defect diminution was greater after volume unloading of the ventricle after cavopulmonary connection than after pulmonary artery banding.

Echocardiographic morphometry and geometry of the left ventricular outflow tract in fixed subaortic stenosis

Objectives. This study was designed to identify, by echocardiography, morphometric abnormalities of the left ventricular out-flow tract in children with fixed subaortic stenosis and to determine whether these abnormalities precede the development of subaortic obstruction.Background. Fixed subaortic stenosis typically develops and progresses after the 1st year of life and is therefore often regarded as an acquired lesion. Although it has been speculated that there may be an underlying anatomic substrate, there are no data to support this hypothesis.Methods. The size of the aortic annulus, mitral-aortic valve separation, aorto-left ventricular septal angle and degree of aortic override were determined in two groups of children. Group 1 comprised 35 patients with isolated subaortic stenosis noted on initial echocardiogram who were compared with an age- and weight-matched normal control group (Group 1A). Group 2 comprised 23 patients with ventricular septel defect or coarctation of the aorta, or both, who had no subaortic stenosis on initial echocardiogram but who developed it subsequently. This group was compared with an age-, weight- and lesion-matched control group (Group 2A).Results. Compared with control subjects, patients with isolated subaortic stenosis hed a significantly wider mitral-aortic separation ([mean ± SD] 5.1 ± 1.3 vs. 3.4 ± 0.9 mm, p < 0.001), a steeper aortoseptal angle (131 ± 6 ° vs. 144 ± 5 °, p < 0.001) and an exaggerated aortic override (p < 0.05). Similar differences were found on initial echocardiogram in Group 2 patients before development of subaortic stenosis: wider mitral-aortic separation (4.2 ± 1.2 vs. 2.5 ± 0.7 mm, p < 0.001), a steeper aortoseptal angle (132 ± 7 ° vs. 145 ± 7 °, p < 0.001) and an exaggerated aortic override (p < 0.05).Conclusions. A left ventricular outflow tract malformation characterized by a wider mitral-aortic separation, an exaggerated aortic override and a steeper aortoseptal angle are present in children with ventricular septal defect or coarctation of the aorta or both, who subsequently develop subaortic stenosis. These morphometric features can be used to identify by echocardiography patients who are at risk for developing fixed subaortic stenosis.

Univentricular atrioventricular connection with subaortic stenosis: a staged surgical approach.

A staged surgical approach was developed for the management of hearts with univentricular atrioventricular connection (double-inlet left ventricle or tricuspid atresia) and discordant ventriculoarterial connection with anatomical substrate for the development of subaortic stenosis. This consisted of initial palliation with pulmonary artery banding, followed by early elective relief of subaortic obstruction using a proximal pulmonary artery to ascending aorta anastomosis in infancy. Pulmonary blood flow was maintained at this time by creating a bidirectional superior cavopulmonary anastomosis. Over an 18-month period, 5 children, including 4 seen in the first week of life with aortic arch obstruction, were palliated with this approach. All patients survived operation and are asymptomatic with transcutaneous oxygen saturations of 80% to 85%. Completion of cavopulmonary repair is planned at 2 years of age. Although some authors have considered pulmonary artery banding contraindicated in these infants, the current staged approach offers an attractive alternative to the construction of a pulmonary artery to aorta anastomosis in the neonatal period.

Subaortic stenosis, the univentricular heart, and banding of the pulmonary artery: an analysis of the courses of 43 patients with univentricular heart palliated by pulmonary artery banding.

Subaortic stenosis is well known to complicate the clinical course of patients with single ventricle or univentricular hearts, and we have previously suggested that the development of subaortic stenosis in such patients may be causal to and/or accelerated by previous banding of the main pulmonary trunk. To further define the relationship between banding of the pulmonary artery in patients with univentricular hearts and the development of subaortic stenosis, we examined the morphologic substrate and timing of the development of subaortic stenosis in 43 patients seen at our institution from January 1, 1970, through June 30, 1985. These 43 patients include all patients in this period with an unequivocal univentricular heart whose longitudinal data was available for follow-up. We excluded patients who died within 1 week of surgery, patients lost to follow-up, and patients with evidence of subaortic stenosis before banding. Thirty-one of 43 patients (72.1%) developed subaortic stenosis subsequent to banding of the main pulmonary artery. The mean age at banding of those patients who developed subaortic stenosis was 0.21 years, and subaortic stenosis was recognized at a mean age of 2.52 years. For the specific cohort of patients whose ventricular morphology was a main chamber of left ventricular type supporting the pulmonary artery and a rudimentary right ventricle supporting the transposed aorta (32 patients), 27 developed subaortic stenosis (84.4%). Subaortic stenosis in the classic form of single ventricle usually results from progressive restriction of a wholly muscular interventricular communication. Banding of the pulmonary artery by producing myocardial hypertrophy undoubtedly accelerates the potential for subaortic stenosis in these patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Observations on the Development of Subaortic Stenosis Following Pulmonary Artery Banding

The development of hemodynamically significant muscular subaortic stenosis in association with pulmonary artery banding is described in one patient with D-transposition of the great arteries, and another with interrupted aortic arch. It is postulated from these and previously reported cases that hypertrophy of the conal septum (crista supraventricularis), whether subpulmonary or subaortic, congenitally displaced or grossly normal, may follow pulmonary artery banding and result in progressive subaortic outflow obstruction. Surgical repair may require resection of conal musculature.

Development of subaortic stenosis after pulmonary artery banding.

Palliation of children with large ventricular septal defects (VSD) by pulmonary artery banding (PAB) is associated with a variety of unfavorable sequelae. We document another possible complication of PAB, the development of subaortic stenosis, which occurred in 4 of 40 infants with large VSD and PAB. Prior to surgery all had congestive heart failure, cardiomegaly, pulmonary plethora, and biventricular or right ventricular hypertrophy on electrocardiogram. At cardiac catheterization all had large VSD with pulmonary artery hypertension. No gradient between left ventricle and systemic artery was demonstrated. PAB was followed by improvement in all four children. Repeat catheterization at 4 to 11 years of age revealed that they had developed a significant (30 to 100 mm Hg) gradient across the left ventricular outflow tract. Although the etiology of the subaortic stenosis is not known, it is felt that the hypertrophied and possibly leftward deviated conal septum was impinging on the left ventricular outflow tract in three of the four. Since the subaortic stenosis was not suspected prior to the second catheterization, we feel that preoperative evaluation of children with VSD and PAB should include evaluation of the left ventricular outflow tract to be certain that no obstruction is present.