Immediate and follow-up results of transluminal balloon dilation for discrete subaortic stenosis

Long-Term Outcome of Patients With Isolated Thin Discrete Subaortic Stenosis Treated by Balloon Dilation

Background—

Transluminal balloon tearing of the membrane in a thin discrete subaortic stenosis is an alternative to membrane surgical resection. However, the long-term outcome of patients with isolated thin discrete subaortic stenosis treated by transluminal balloon tearing remains unknown.

Methods and Results—

This 25-year study describes findings from 76 patients with isolated thin discrete subaortic stenosis who underwent percutaneous transluminal balloon tearing of the membrane and were followed up for a mean period of 16±6 years. The age at presentation had a wide range (2–67 years). The mean age at treatment was 19±16 years. Immediately after treatment, the subvalvular gradient decreased from 70±27 to 18±12 mm Hg ( P <0.001). No significant postprocedural aortic regurgitation was observed. After a mean follow-up time of 16±6 years, 11 patients (15%) developed restenosis, 3 patients (4%) progressed to muscular obstructive disease, and 1 patient (1.3%) developed a new distant obstructive membrane. Twelve patients (16%) were redilated at a mean of 5±3 years after their first treatment, and 4 patients (5%) underwent surgery at a mean of 3±2 years after their first treatment. Fifty-eight patients (77%) remained alive and free of redilation or surgery at follow-up. Larger annulus diameter and thinner membranes were independent factors associated with better long-term results.

Conclusions—

Most patients (77%) with isolated thin discrete subaortic stenosis treated with transluminal balloon tearing of the membrane had sustained relief at subsequent follow-ups without restenosis, the need for surgery, progression to muscular obstructive disease, or an increase in the degree of aortic regurgitation.

Surgical outcome following treatment of isolated subaortic obstruction

Surgical and nonsurgical patients with isolated subaortic stenosis (SAS) were compared to determine the important factors contributing to the timing of surgical intervention. This study reviews 49 consecutive patients (27 surgical and 22 nonsurgical) aged 1.8 to 15.9 years with isolated SAS. The preoperative peak left ventricular outflow tract (LVOT) gradient in surgical patients was significantly higher than the gradient in nonsurgical patients (59.0 +/- 30.4 vs 22.77 +/- 13.9 mm Hg, P = .0001). The progression in LVOT gradient analyzed by echo Doppler was significantly higher in the surgical group compared with the nonsurgical group (10.48 +/- 9.7 vs 1.56 +/- 6.5 mm Hg/y, P = .007). Repeat surgical intervention was required in 22% of patients in the surgical group for recurrence of SAS, and 4% needed a third surgery. The progression in the severity of aortic regurgitation (AR) was not significantly different in the surgical and nonsurgical groups. There was a significant association between the development of AR and patients undergoing surgery (P = .045). AR may not be a reliable indication for early operative intervention in isolated SAS as there was no significant difference in its progression with surgical and nonsurgical patients. Asymptomatic patients with isolated SAS may warrant surgical intervention on the basis of progression of LVOT gradient, rather than the development or progression of AR.

Incidence and prognosis of obstruction of the left ventricular outflow tract in Liverpool (1960-91): a study of 313 patients

OBJECTIVE

To determine the incidence of the various types of obstruction of the left ventricular outflow tract in patients born in the five health districts of Liverpool and to compare their prognosis into early adult life.

DESIGN

Notes of all patients with obstruction of the left ventricular outflow tract born in the study area between 1960 and 1991 were reviewed. Patients with hypoplastic left ventricle, mitral valve atresia, and those with discordant atrioventricular or ventriculoarterial connections were excluded. Survivors were traced and assessed clinically; eight were lost to follow up.

RESULTS

Obstruction of the left ventricular outflow tract occurred in 313 patients (67% male), giving an incidence of 6.1/10,000 live births. The median (range) age at presentation was 13.9 months (0-20 yr). Aortic valve stenosis occurred in 71.2%: subvalve in 13.7%, supravalve in 7.7%, and multilevel in 7.4%. The median (range) duration of follow up was 10.0 (1-29) yr. Aortic regurgitation at presentation occurred more often (p < 0.001) in patients with subvalve stenosis than in those with other types of obstruction, but there was an increased incidence (p < 0.001) at follow up in patients with valve stenosis. Ninety eight patients (31.3%) underwent operation. The reoperation rate was 27% for valve stenosis and 9% for subvalve obstruction. No patients with supravalve stenosis underwent reoperation. The median duration from first operation to aortic valve replacement (17 patients) was 12.3 years. Hazard analysis confirmed that the risk of death was higher in patients presenting at a younger age, with more severe stenosis, and those with subaortic, multilevel obstruction or a syndrome. Hazard analysis also showed that the risk of a clinical event (surgery, balloon dilatation, or endocarditis) was greater in patients who presented at a younger age, with more severe stenosis or aortic regurgitation, and in those with subvalve or multilevel obstruction.

CONCLUSIONS

Aortic valve stenosis was the most common type of obstruction. Hazard analysis indicates that the age and severity of obstruction at presentation have a significant effect on survival and freedom from a clinical event. The risk of premature death in patients presenting with moderately severe valve stenosis is reasonably small, but increases considerably in those with subvalve, supravalve, and multilevel obstruction. Patients who present with mild valve stenosis have a good prognosis. The risk of sudden death is less than previous predictions. Patients with subvalve and multilevel obstruction, even when mild at presentation, are more likely to undergo intervention or develop endocarditis than those with valve or supravalve stenosis. Follow up into adult life is essential.

Initial experience with balloon dilatation of supravalvar aortic stenosis

Primary balloon dilatation of supravalvar aortic stenosis was attempted in three patients: a 20 year old woman, a seven month old boy, and a 12 year old girl. Balloon catheters (Mansfield) with diameters of 25 mm, 8 mm, and 15 mm were used in the three patients respectively. The systolic pressure gradient across the aortic narrowing decreased considerably and the diameter of the constricted area increased significantly. Balloon dilatation was feasible and provided good immediate results and sustained relief of supravalvar aortic stenosis in these three patients. However, a larger study is needed to establish the place of this procedure in treatment.

Echocardiographic assessment of subvalvular aortic stenosis before and after operation

The development of two-dimensional and Doppler echocardiography has provided a noninvasive technique for the diagnosis and serial assessment of patients with subvalvular aortic stenosis. The clinical records and echocardiographic data were reviewed of all patients with subaortic stenosis diagnosed between 1983 and 1991. Of the 77 patients identified (45 male and 32 female), 28 had isolated subaortic stenosis and 49 had associated cardiac lesions. The most frequently encountered associated lesions were ventricular septal defect (n = 19) and coarctation of the aorta/interrupted aortic arch (n = 14). Serial echocardiographic studies, performed in 38 of the 77 patients, documented significant progression of the left ventricular outflow tract gradient in 25 patients (66%) and development of aortic regurgitation in 25 patients (66%). Surgical resection was performed in 36 patients. The preoperative outflow tract peak gradient was 62.9 +/- 31 mm Hg (range 0 to 153), whereas the immediate postoperative gradient was 14.4 +/- 14 mm Hg (range 0 to 67). The two patients with a significant residual gradient (37 and 67 mm Hg, respectively) in the immediate postoperative period had severe subaortic stenosis preoperatively with marked left ventricular hypertrophy and intracavitary gradient. The immediate postoperative echocardiograms demonstrated no worsening of aortic regurgitation in any patient and regression of regurgitation in one patient from mild to none. Intermediate-term follow-up studies were available for review in 13 postoperative patients at a mean of 4 years postoperatively. In 2(15%) of these 13 patients, subaortic stenosis recurred; however, the degree of aortic regurgitation did not increase in any patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Management of fixed subaortic stenosis: a retrospective study of 57 cases

Although recommended by several investigators, the benefit of early surgery in patients with fixed subaortic stenosis has not been proved. Findings were reviewed of 57 patients with isolated fixed subaortic stenosis, including 27 surgically treated patients, with special emphasis on the occurrence of aortic regurgitation during a mean follow-up period of 6.7 years. The number of patients with aortic regurgitation increased preoperatively in the total group (23% at diagnosis to 54% after 3.7 years of follow-up). The prevalence of aortic regurgitation in the 27 surgically treated patients was higher (81%) than that in the nonsurgically treated group but remained unchanged after a mean postoperative period of 4.7 years. In all patients but one, aortic regurgitation remained of minor hemodynamic significance. One patient died during follow-up. After surgery, 15 patients (55%) showed a relapse; 11 redeveloped a subvalvular pressure gradient greater than 30 mm Hg and discrete subvalvular ridges (range 6 months to 24 years after surgery, mean 7 years). In those patients with fixed subaortic stenosis, follow-up did not reveal any benefit from early surgery. The unpredictable course and sometimes very severe progression of this disease make frequent and careful follow-up necessary.