Surgical Relief of Left Ventricular Outflow Tract Obstruction in Adults With Congenital Aortic Stenosis and Associated Aortic Annulus Hypoplasia and/or Subaortic Obstruction.

BACKGROUND: In children and adolescents, a Ross/Konno operation is commonly done to both enlarge the aortic root and provide a competent aortic valve with relief of left ventricular outflow tract obstruction (LVOTO). Optimum management is not so straightforward in adults. METHODS: Between 1995 and 2014, 16 patients of mean age 39.4 years (18-57 years) with hypoplastic aortic annulus (AA) measuring 20mm and less, and mean aortic valve/LVOT gradient of 61mmHg (30-70mmHg) presented for surgery. RESULTS: Eight patients with mean LVOT/AA diameter 19.6mm (18-20mm) underwent an "inclusion-cylinder" type Ross procedure (RP). Eight patients with more severe LVOT/AA obstruction, with mean diameter of 17.4mm (16-19mm) underwent mechanical aortic valve replacement (AVR) with standard Konno-type aortoventriculoplasty. There was zero early and late mortality; with mean follow-up of 11.6 years (3-21 years) in the Ross group and 6 years (2-10 years) in the Konno-AVR group. One patient in the Konno-AVR group had reoperation after 2 years for RVOT obstruction. The postoperative echocardiograms of these patients at last follow-up show residual mean gradient across LVOT/AA of 4.4mmHg (2-6mmHg) after RP, and 11.9mmHg (8-17mmHg) after Konno-AVR. CONCLUSIONS: In adults, the "inclusion-cylinder" Ross-procedure is a good alternative for mild to moderate aortic root hypoplasia. However, for cases with severe LVOT obstruction, a Ross-Konno is not possible with the same method of autologous support used in a non-Konno RP, and this could be expected to have an impact on late durability and the need for further intervention, in a group that has already undergone multiple procedures in childhood. Both methods of RP and Konno-AVR lead to excellent early and late results.

Aortopulmonary window with subaortic fibrous stenosis and septal defect: surgery through a minimal right vertical infra-axillary thoracotomy.

Aortopulmonary window with subaortic stenosis and ventricular septal defect is an uncommon congenital cardiac malformation that is repaired using cardiopulmonary bypass. The authors describe a 3-year-old patient on whom we performed surgery through a minimal right vertical infra-axillary thoracotomy. This minimally invasive surgery is likely to be applicable in a few cases.

Long-term pediatric outcome of isolated discrete subaortic stenosis.

BACKGROUND: The management of pediatric discrete subaortic stenosis remains controversial. OBJECTIVES: Document the natural history and surgical outcomes for discrete subaortic stenosis to adolescence. METHODS: Retrospective review of clinical and echocardiographic findings in 74 patients diagnosed in childhood between 1985 and 1998. RESULTS: Twenty-five patients were followed only medically for 9.4 ± 0.9 years to 15.9 ± 0.6 years of age. Their echocardiographic left ventricular outflow peak gradient did not progress, 19 ± 1.4 (SEM) vs 20 ± 2.3 mm Hg. The proportion with aortic insufficiency (AI) increased (4% to 52%). Forty-nine patients were operated for discrete subaortic stenosis at 7.8 ± 0.6 years. Their peak gradient at diagnosis was 36 ± 3 mm Hg with AI in 33%. Preoperatively their peak gradient progressed to 60 ± 5 mm Hg with AI in 82%. Assessment 6.2 ± 0.5 years postoperativly showed a peak gradient of 14 ± 2 mm Hg with AI in 88%. Ten patients required reoperation for recurrent discrete subaortic stenosis, 3 acquired complete heart block, and 1 developed endocarditis. There was no mortality. At diagnosis, surgical patients were younger, had greater peak gradients, and greater incidence of AI, than those followed only medically. The progression of discrete subaortic stenosis was positively associated with severity of obstruction and negatively associated with older age at diagnosis. The risk of having surgery over time was associated with greater preoperative obstruction and presence of AI. CONCLUSIONS: Many pediatric patients with mild discrete subaortic stenosis exhibit little progression of obstruction and need not undergo immediate surgery. Others with more severe stenosis may progress precipitously and will benefit from early resection.

Congenital heart diseases in the boxer dog: A retrospective study of 105 cases (1998-2005).

Subaortic stenosis (SAS) is one of the most common congenital heart diseases (CHD) in dogs with Boxers being predominantly affected. However, the increasing availability of modern diagnostic imaging systems now allows a better assessment of cardiac morphology and function, thereby facilitating early detection of CHD in awake animals. In this context, the case records of Boxer dogs diagnosed with CHD using echocardiography combined with Doppler mode, were retrospectively reviewed (1998-2005). One hundred and five Boxers exhibiting either a single CHD (53/105, 50.5%) or association of several CHD (52/105, 49.5%) were included. The most common CHD was atrial septal defect (ASD) observed in 56.2% of these animals (59/105), followed by mitral dysplasia (58/105, 55.2%), and SAS (49/105, 46.7%). SAS was associated with one or two CHD in 29.5% of cases (31/105). Most of the dogs with a low intensity left heart base systolic murmur had an isolated ASD whereas most of the dogs with a similar but high intensity murmur had SAS, either isolated or associated with a concurrent CHD. The incidence of ASD and mitral dysplasia in Boxer dogs is higher than previously assumed, and ASD is a common cause of left heart base systolic murmur in this breed of dog. This confirms that the detection of such a murmur should not be used as the unique criterion for diagnostic confirmation of SAS.

Pulmonary artery banding before the Damus-Kaye-Stansel procedure.

Subaortic stenosis (SAS) in a single ventricle leads to myocardial hypertrophy and compromises Fontan results. Moreover, controversy exists concerning the optimal surgical strategy for relieving SAS. We have applied pulmonary artery banding (PAB) before the Damus-Kaye-Stansel procedure (DKS), and here we analyze factors that influence systemic ventricular compliance. Thirteen patients underwent PAB before DKS. Median PAB duration was 5.5 months (range, 20 days to 17.7 months). Procedures administered concomitantly with DKS were Blalock-Taussig shunt (n = 6), bidirectional cavopulmonary shunt (n = 5), and Fontan operation (n = 2). All survived and were doing well after a median follow-up 2.7 years. Cardiac catheterization before DKS showed that the mean pressure gradient across the systemic ventricular outflow tract and PAB were 20.6 +/- 10.1 and 67.4 +/- 10.2 mmHg, respectively. After DKS, systemic ventricular end diastolic pressure (SVEDP) was significantly correlated with PAB duration (r = 0.65, p = 0.022), but not with PAB or systemic ventricle outflow tract pressure gradients. After DKS, SVEDP decreased or fell to within the range in patients with PAB duration less than 7 months (p < 0.05). Seven patients had a successful Fontan operation, and 6 without risk factors are waiting operation. SVEDP was found to be correlated with PAB duration, and our findings indicate that short-term PAB can be considered a safe option in patients with a single ventricle and SAS.

Considerations in biventricular repair after the Norwood procedure.

OBJECTIVE: The Norwood procedure can be applicable as a first stage palliation in children who can eventually undergo a biventricular repair. Although usual management of these patients is a primary neonatal repair, in selected patients staged approach with a Norwood procedure in the neonatal period followed by a Rastelli procedure in the infancy for conversion to two-ventricle physiology has been used alternatively. METHODS: We report our experiences on two infants who underwent a previous palliation with the Norwood procedure for lesions other than hypoplastic left heart syndrome and converted to two-ventricle physiology by the use of a Rastelli-type procedure. This report examines considerations in biventricular repair after the Norwood procedure especially need for ventricular septal defect enlargement and approach to placement of the right ventricle to pulmonary artery conduit. RESULTS: Both of the infants who underwent staged approach with an initial Norwood procedure for lesions other than hypoplastic left heart syndrome survived the operations and were clinically well at mid-term follow-up. CONCLUSION: In selected patients, the staged approach is an alternative in management of malformations other than hypoplastic left heart syndrome which share the important physiologic features of aortic outlet obstruction and ductal dependency of systemic circulation. We recommend routine enlargement of ventricular septal defect and proper positioning of the conduit at the time of subsequent biventricular repair.

Balloon dilation of discrete subaortic stenosis associated with other cardiac defects in children.

Balloon dilation (BD) is reported as an effective treatment for isolated discrete thin membranous subaortic stenosis (SAS). We asked if BD of SAS with associated cardiac defects: 1) is effective; 2) creates or worsens mitral insufficiency in the presence of valvar membrane attachment; and 3) creates or worsens aortic insufficiency. BD was performed on 13 patients (9 females, 4 males with a mean age of 5.8 years and an age range of 1-14 years old) for SAS with the following associated defects: VSD (6 patients), coarctation (4 patients), complete atrioventricular canal (1 patient), tetralogy of Fallot (1 patient), and abnormal mitral valve (4 patient). Prior intracardiac surgical procedures (3 for SAS resection) had been performed in 46% of the study group. Peak gradient was reduced from 53 +/- 40 mmHg to 31 +/- 25 mmHg (p < 0.01). The resulting gradient was related to the predilation gradient (r = 0.71; p =.006). Thin membranes (< 3 mm) were associated with lower initial gradient (p < 0.02), lower resulting gradient (p < 0.001) and a greater percent gradient reduction (76% versus 36%; p < 0.01). Aortic insufficiency, which was present predilation in 77%, did not change and was not created in any patient. Mitral valve membrane attachment was present in 69% and associated with a lower resulting gradient (p < 0.006). Mitral insufficiency was not created in 10 patients, was unchanged in 2 and was improved in 1 patient. Surgical procedures were ultimately required in 8 patients during follow-up. BD of SAS associated with other cardiac defects achieves the following: 1) reduces SAS gradient in selected patients without creating or worsening aortic insufficiency; 2) does not create or worsen mitral insufficiency when mitral valve membrane attachment is present; 3) improves preoperative hemodynamics; and 4) is unlikely to be effective in post-surgical recurrence.