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

Congenital, acquired, or both? The only two congenitally based, acquired heart diseases

Discrete subaortic stenosis (DSS) is a type of left ventricular outflow tract obstruction whereas double-chambered right ventricle is a form of right ventricular outflow tract obstruction. Both of these cardiac malformations share lots of similar characteristics which classify them as acquired developmental heart diseases despite their congenital anatomical substrate. Both of them are frequently associated to ventricular septal defects. The initial stimulus in their pathogenetic process is anatomical abnormalities or variations. Subsequently, a hemodynamic process is triggered finally leading to an abnormal subaortic fibroproliferative process with regard to DSS or to hypertrophy of ectopic muscles as far as double-chambered right ventricle is concerned. In many cases, these pathologies are developed secondarily to surgical management of other congenital or acquired heart defects. Moreover, high recurrence rates after initial successful surgical therapy, particularly regarding DSS, have been described. Finally, an interesting coexistence of DSS and double-chambered aortic ventricle has also been reported in some cases.

Computational Assessment of Valvular Dysfunction in Discrete Subaortic Stenosis: A Parametric Study

PURPOSE

Discrete subaortic stenosis (DSS) is a left-ventricular outflow tract (LVOT) obstruction caused by a membranous lesion. DSS is associated with steep aortoseptal angles (AoSAs) and is a risk factor for aortic regurgitation (AR). However, the etiology of AR secondary to DSS remains unknown. This study aimed at quantifying computationally the impact of AoSA steepening and DSS on aortic valve (AV) hemodynamics and AR.

METHODS

An LV geometry reconstructed from cine-MRI data was connected to an AV geometry to generate a unified 2D LV-AV model. Six geometrical variants were considered: unobstructed (CTRL) and DSS-obstructed LVOT (DSS), each reflecting three AoSA variations (110°, 120°, 130°). Fluid-structure interaction simulations were run to compute LVOT flow, AV leaflet dynamics, and regurgitant fraction (RF).

RESULTS

AoSA steepening and DSS generated vortex dynamics alterations and stenotic flow conditions. While the CTRL-110° model generated the highest degree of leaflet opening asymmetry, DSS preferentially altered superior leaflet kinematics, and caused leaflet-dependent alterations in systolic fluttering. LVOT steepening and DSS subjected the leaflets to increasing WSS overloads (up to 94% increase in temporal shear magnitude), while DSS also increased WSS bidirectionality on the inferior leaflet belly (+ 0.30-point in oscillatory shear index). Although AoSA steepening and DSS increased diastolic transvalvular backflow, regurgitant fractions (RF < 7%) remained below the threshold defining clinical mild AR.

CONCLUSIONS

The mechanical interactions between AV leaflets and LVOT steepening/DSS hemodynamic derangements do not cause AR. However, the leaflet WSS abnormalities predicted in those anatomies provide new support to a mechanobiological etiology of AR secondary to DSS.

Echocardiographic predictors of reoperation for subaortic stenosis in children and adults

OBJECTIVES

Subaortic stenosis (SAS) can present as various types of obstruction of the left ventricular outflow tract (LVOT) below the level of the aortic valve. Even though corrective surgery has been identified as the most effective treatment, SAS more frequently reoccurs requiring reoperation in a significant proportion of the patients. Previous studies have focused on predictors of recurrence in various subgroups of patients with SAS, but rarely in the overall population of patients with SAS. The aim of this study was to determine the predictors of recurrence of SAS after initial corrective surgery.

METHODS

Patients from the database of the Congenital Cardiology Department of the University Hospital of Southampton with significant SAS requiring corrective surgery were included in the study. Data retrieved were obtained and used to determine the predictors of SAS recurrence after the initial corrective surgery.

RESULTS

Eighty-two patients (paediatric, n = 72 and adult, n = 10) who underwent initial successful resection were included in the analysis. Thirty patients required reoperation for recurrent SAS. These were significantly younger (median age 3.0 vs 6.7 years, P = 0.002). The recurrence of SAS was more common in patients with an interrupted aortic arch (23.3% vs 3.8%, P = 0.010) and unfavourable left ventricle geometry (43.3% vs 7.6%, P < 0.001), with steeper aortoseptal angle (131.0° ± 8.7° vs 136.1° ± 8.6°, P = 0.030), shorter distance between the point of obstruction of the LVOT and the aortic valve annulus in systole and diastole (median 4.30 vs 5.90 mm, P = 0.003 and 3.65 vs 4.95 mm, P = 0.006, respectively) and in those who had higher residual peak and mean LVOT gradients postoperatively (29.3 ± 16.0 vs 19.8 ± 10.7 mmHg, P = 0.006 and 15.9 ± 8.3 vs 10.1 ± 5.8 mmHg, P = 0.002, respectively). Overall, the presence of an interrupted aortic arch [odds ratio (OR) 10.34, 95% confidence interval (CI) 1.46-73.25; P < 0.019] and unfavourable left ventricle geometry (OR 10.42, 95% CI 1.86-58.39; P < 0.008) could independently predict reoperation for SAS after initial successful resection.

CONCLUSIONS

Patients who have initial corrective surgery for SAS at a younger age, unfavourable left ventricle geometry, an interrupted aortic arch and higher early postoperative LVOT gradients are more likely to have recurrent SAS requiring reoperation.

Long-term follow-up and outcomes of discrete subaortic stenosis resection in children

Background

Studies of long-term outcomes of discrete subaortic stenosis (DSS) are rare. Therefore, we reviewed the long-term outcomes of subaortic membrane resection in children with isolated DSS over 16 years from a single institution.

Materials and Methods

We retrospectively reviewed the records of patients (n = 27) who underwent resection of DSS between 2000 and 2017. Patients with major concomitant intracardiac anomalies were excluded. Indications for surgery were mean left ventricular outflow tract (LVOT), Doppler gradient >30 mmHg, and/or progressive aortic insufficiency.

Results

The mean age at diagnosis was 3.77 ± 3.49 years (range, 0.25-13 years) and the mean age at surgery was 6.36 ± 3.69 years (range, 1-13 years). All patients underwent resection of subaortic membrane. The mean LVOT Doppler gradient decreased from 40.52 ± 11.41 mmHg preoperatively to 8.48 ± 5.06 mmHg postoperatively (P < 0.001). The peak instantaneous LVOT Doppler gradient decreased from 75.41 ± 15.22 mmHg preoperatively to 18.11 ± 11.44 mmHg postoperatively (P < 0.001). At the latest follow-up, the peak gradient was 17.63 ± 8.93 mmHg. The mean follow-up was 7.47 ± 3.53 years (median 6.33 years; range 2.67-16 years). There was no operative mortality or late mortality. Recurrence of subaortic membrane occurred in 7 (25.92%, 7/27) patients who underwent primary DSS operation. Four (14.81%, 4/27) patients required reoperation for DSS recurrence at a median time of 4.8 years (3.1-9.1 years) after the initial repair. Risk factors for reoperation were age <6 years at initial repair. Eighteen (66.66%, 18/27) patients had AI preoperatively and progression of AI occurred in 70.37% (19/27). This included 4 (22.22%, 4/18) patients who had worsening of their preoperative AI. Short valve-to-membrane distance was found to be prognostically unfavorable. One (3.7%, 1/27) patient had an iatrogenic ventricular septal defect, and 2 (7.4%, 2/27) patients had complete AV block following membrane resection.

Conclusions

Resection of subaortic membrane in children is associated with low mortality. Higher LVOT gradient, younger age at initial repair, and shorter valve-to-membrane distance were found to be associated with adverse outcome. Recurrence and reoperation rates are high, and progression of aortic insufficiency following subaortic membrane resection is common. Therefore, these patients warrant close follow-up into adult life.

Intraoperative transesophageal echocardiographic predictors of recurrent left ventricular outflow tract obstruction in children undergoing subaortic stenosis resection

BACKGROUND

Intraoperative transesophageal echocardiography (iTEE) is used to assess for residual left ventricular outflow tract obstruction (LVOTO) after surgical resection of subaortic membrane causing subaortic stenosis (sub-AS). We aimed to identify the iTEE features associated with recurrence of LVOTO.

METHODS

We conducted a retrospective study of children undergoing sub-AS resection from June 2006 to June 2014. Doppler assessment of the flow velocity and the anatomical features of the left ventricular outflow tract were analyzed from stored echocardiograms. Recurrent LVOTO was defined as an increase in the mean pressure gradient across the left ventricular outflow tract of > 15 mm Hg on the most recent follow-up echocardiogram from the mean pressure gradient on the predischarge echocardiogram or as doubling of the mean pressure gradient to a value ≥20 mm Hg.

RESULTS

Thirty-five patients were included, with median age at surgery was 8.1 years (range: 0.7-29 years) and median follow-up was 47 months (2-91 months). Ten patients (29%) had recurrent LVOTO, which was associated with a shorter distance between the narrowest diameter of the outflow tract and the aortic valve on iTEE [median 0.59 cm (range 0.39-0.74) vs 0.98 cm (0.75-1.5), P = .03]. No patients with more than mild residual LVOTO on iTEE regressed to mild or no LVOTO on follow-up echocardiograms.

CONCLUSIONS

LVOTO recurrence after sub-AS resection is common, and residual LVOTO remains the same or increases over time. Proximity of the LVOTO to the aortic valve is a risk factor for recurrent LVOTO. These findings may be useful in counseling patients and to guide the frequency of postoperative follow-up.

Long-term outcomes and risk factors for aortic regurgitation after discrete subvalvular aortic stenosis resection in children

OBJECTIVES

To characterise long-term outcomes after discrete subaortic stenosis (DSS) resection and to identify risk factors for reoperation and aortic regurgitation (AR) requiring repair or replacement.

METHODS

All patients who underwent DSS resection between 1984 and 2009 at our institution with at least 36 months' follow-up were included. Demographic, surgical and echocardiographic data were reviewed. Outcomes were reoperation for recurrent DSS, surgery for AR, death and morbidities, including heart transplant, endocarditis and complete heart block.

RESULTS

Median length of postoperative follow-up was 10.9 years (3-27.2 years). Reoperation occurred in 32 patients (21%) and plateaued 10 years after initial resection. Survival at 10 years and 20 years was 98.6% and 86.3%, respectively. Aortic valve (AoV) repair or replacement for predominant AR occurred in 31 patients (20%) during or after DSS resection. By multivariable analysis, prior aortic stenosis (AS) intervention (HR 22.4, p<0.001) was strongly associated with AoV repair or replacement. Risk factors for reoperation by multivariable analysis included younger age at resection (HR 1.24, p=0.003), preoperative gradient ≥60 mm Hg (HR 2.23, p=0.04), peeling of membrane off AoV or mitral valve (HR 2.52, p=0.01), distance of membrane to AoV <7.0 mm (HR 4.03, p=0.03) and AS (HR 2.58, p=0.01).

CONCLUSIONS

In this cohort, the incidence of reoperations after initial DSS resection plateaued after 10 years. Despite a significant rate of reoperation, overall survival was good. Concomitant congenital AS and its associated interventions significantly increased the risk of AR requiring surgical intervention.

Fixed subaortic stenosis: a clinical dilemma for clinicians and patients

Subaortic stenosis carries considerable morbidity and mortality. In most cases, patients have an underlying left ventricular outflow tract morphology that promotes turbulence at the outflow tract, which induces the development of subaortic fibromuscular tissue. A subset of patients will progress to develop severe stenosis and aortic regurgitation, but it has been difficult to determine which patients are at risk. While resection of the subaortic tissue improves immediate outcome, many patients have recurrence of both stenosis and regurgitation, questioning the efficacy of surgical intervention in asymptomatic patients. This review article describes the current understanding of the etiology, treatment, and prognosis of subaortic stenosis.

Evaluation of subvalvular aortic stenosis in children: a 16-year single-center experience

Subvalvular aortic stenosis accounts for 1-2 % of all congenital heart disease and for 8-20 % of cases of left-ventricular outflow tract (LVOT) obstruction in children. Recurrence of subaortic stenosis (SAS) is not uncommon after surgical management. This study was performed to investigate the clinical and surgical outcomes and to estimate the predictability of recurrences of SAS. Seventy-nine patients age 3-21 years with SAS between 1994 and 2010 were reviewed. Fifty-one patients had discrete SAS, whereas the remaining 15 patients had fibromuscular ridge-type SAS. Mean follow-up time without surgery was 22 months (range of 1-94). Forty-one patients with a diagnosis of SAS underwent surgery. Recurrence rates were 22.7 % (15 patients), and these patients developed SAS at a mean of 4.7 years follow-up. We performed second surgical membrane resection in only 1 patient. The risk of recurrence of SAS was only linked to higher preoperative LVOT gradient. Twenty-three patients had no aortic regurgitation (AR) at preoperative echocardiography. Of these, 39.1 % had trivial, 8.7 % had mild, and 8.7 % had moderate AR after surgery; there was no significant AR. We conclude that surgical intervention was required most of the time in patients with SAS, and surgical outcomes was excellent even if there were associated cardiac defects. The risk of recurrences was higher, especially in patients with higher initial LVOT gradients, although a second surgery was rarely necessary in these patients.

Surgical outcome of discrete subaortic stenosis in adults: a multicenter study

BACKGROUND

Discrete subaortic stenosis is notable for its unpredictable hemodynamic progression in childhood and high reoperation rate; however, data about adulthood are scarce.

METHODS AND RESULTS

Adult patients who previously underwent surgery for discrete subaortic stenosis were included in this retrospective multicenter cohort study. Mixed-effects and joint models were used to assess the postoperative progression of discrete subaortic stenosis and aortic regurgitation, as well as reoperation. A total of 313 patients at 4 centers were included (age at baseline, 20.2 years [25th-75th percentile, 18.4-31.0 years]; 52% male). Median follow-up duration was 12.9 years (25th-75th percentile, 6.2-20.1 years), yielding 5617 patient-years. The peak instantaneous left ventricular outflow tract gradient decreased from 75.7±28.0 mm Hg preoperatively to 15.1±14.1 mm Hg postoperatively (P<0.001) and thereafter increased over time at a rate of 1.31±0.16 mm Hg/y (P=0.001). Mild aortic regurgitation was present in 68% but generally did not progress over time (P=0.76). A preoperative left ventricular outflow tract gradient ≥80 mm Hg was a predictor for progression to moderate aortic regurgitation postoperatively. Eighty patients required at least 1 reoperation (1.8% per patient-year). Predictors for reoperation included female sex (hazard ratio, 1.53; 95% confidence interval, 1.02-2.30) and left ventricular outflow tract gradient progression (hazard ratio, 1.45; 95% confidence interval, 1.31-1.62). Additional myectomy did not reduce the risk for reoperation (P=0.92) but significantly increased the risk of a complete heart block requiring pacemaker implantation (8.1% versus 1.7%; P=0.005).

CONCLUSIONS

Survival is excellent after surgery for discrete subaortic stenosis; however, reoperation for recurrent discrete subaortic stenosis is not uncommon. Over time, the left ventricular outflow tract gradient slowly increases and mild aortic regurgitation is common, although generally nonprogressive over time. Myectomy does not show additional advantages, and because it is associated with an increased risk of complete heart block, it should not be performed routinely.

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.

Canadian Cardiovascular Society 2009 Consensus Conference on the management of adults with congenital heart disease: outflow tract obstruction, coarctation of the aorta, tetralogy of Fallot, Ebstein anomaly and Marfan's syndrome

With advances in pediatric cardiology and cardiac surgery, the population of adults with congenital heart disease (CHD) has increased. In the current era, there are more adults with CHD than children. This population has many unique issues and needs. Since the 2001 Canadian Cardiovascular Society Consensus Conference report on the management of adults with CHD, there have been significant advances in the field of adult CHD. Therefore, new clinical guidelines have been written by Canadian adult CHD physicians in collaboration with an international panel of experts in the field. Part II of the guidelines includes recommendations for the care of patients with left ventricular outflow tract obstruction and bicuspid aortic valve disease, coarctation of the aorta, right ventricular outflow tract obstruction, tetralogy of Fallot, Ebstein anomaly and Marfan's syndrome. Topics addressed include genetics, clinical outcomes, recommended diagnostic workup, surgical and interventional options, treatment of arrhythmias, assessment of pregnancy risk and follow-up requirements. The complete document consists of four manuscripts that are published online in the present issue of The Canadian Journal of Cardiology. The complete document and references can also be found at www.ccs.ca or www.cachnet.org.

Risk factors for reoperation after repair of discrete subaortic stenosis in children

OBJECTIVES

This study aimed to identify independent predictors of reoperation after successful resection of discrete subaortic stenosis (DSS).

BACKGROUND

Recurrence of DSS has been reported to range from 0% to 55% of patients. Factors associated with recurrence have not been adequately defined.

METHODS

Patients were included if they had a diagnosis of DSS, normal segmental cardiac anatomy, previous resection of DSS, and at least 36 months' follow-up. Demographic, surgical, and echocardiographic data were analyzed. Primary outcome was repeat resection of DSS in patients after successful primary resection.

RESULTS

Of 111 subjects who had successful surgical resection of DSS, 16 patients (14%) required reoperation. Median follow-up time was 8.2 years. Form of DSS and gender did not differ significantly between those with reoperation and those without. In multivariate analysis, independent predictors of reoperation that would be available before first surgery were <6 mm distance between the aortic valve (AoV) and the obstruction (hazard ratio [HR] 5.1; p = 0.013) and peak gradient by Doppler > or =60 mm Hg (HR 4.2; p = 0.016). If intraoperative variables are also considered, peeling of the membrane from the AoV or mitral valve at first surgery, <6 mm distance between the DSS and AoV, and peak gradient by Doppler > or =60 mm Hg were independent predictors of reoperation.

CONCLUSIONS

Proximity of the obstructive lesion to the AoV and severe obstruction determined by preoperative echocardiography, as well as involvement of valve leaflets requiring surgical peeling, predict recurrent DSS requiring reoperation.

Echocardiographic follow-up of children with isolated discrete subaortic stenosis

This study evaluates the progression of stenosis, onset and progression of aortic regurgitation (AR), and the results of surgical outcomes in children with isolated discrete subaortic stenosis (SAS). The medical records of 108 patients (mean age, 5.5 +/- 3.8 years; range, 3 days to 18 years) with isolated discrete SAS were reviewed. Patients with lesions other than AR were excluded. Very mild stenosis was defined as Doppler peak systolic instantaneous gradient (PSIG) less than 25 mmHg, mild stenosis as 25-49 mmHg, moderate stenosis as 50-75 mmHg, and severe stenosis as more than 75 mmHg. Seventy-eight of 108 patients were followed for 2 months to 14 years (mean, 4.8 +/- 3.7 years; median, 5 years) with medical treatment alone. In these patients, the mean PSIG at last echocardiogram was higher than the mean PSIG at initial echocardiogram (39 +/- 19 vs 31 +/- 12 mmHg, respectively; p < 0.001). Among 24 patients with very mild stenosis at initial echocardiogram, 10 had mild and 2 had moderate stenosis after a mean period of 5.6 years. Among 46 patients with mild stenosis at initial echocardiogram, 11 had moderate and 5 had severe stenosis after a mean period of 4.1 years. Only 1 patient among the 8 patients with moderate stenosis at initial echocardiogram had severe stenosis after a mean period of 2.7 years. Thirty-nine patients (50%) had AR (13% trivial, 33% mild, and 4% moderate) at initial echocardiogram. After a mean period of 4.8 years, 77% of the patients had AR (10% trivial, 53% mild, 9% mild-moderate, and 5% moderate). Twenty-four patients underwent surgery. Preoperatively, mean Doppler PSIG and AR incidence were 64 +/- 17 mmHg and 91% (22/24), respectively. The mean Doppler PSIG was 30 +/- 19 mmHg and AR was present in all of the patients a mean period of 4.1 years after surgery. Two patients underwent reoperation for recurrent SAS and AR. Patients with very mild or mild stenosis may be followed noninvasively every year. One patient of the 8 patients with moderate stenosis progressed to severe stenosis, and moderate AR developed in 2 patients after a mean of 2.7 years. We recommend that patients with moderate stenosis undergo careful evaluation to determine whether surgery is necessary due to the severity of stenosis and AR.

Operative Results and Outcomes in Children With Shone's Anomaly

BACKGROUND

The outcome of children with multilevel left heart obstructions with mitral valve involvement (Shone's anomaly) is generally poor. This study reviews our results and outcomes in patients with staged repair for left ventricular outflow tract obstruction (LVOTO) and mitral valve reconstruction.

METHODS

A total of 27 children underwent staged repair for Shone's anomaly between 1978 and 2003. The mean age at the first operation was 9.0 months (range, 2 days to 3 years). Mitral stenosis was present in all; with supravalvular mitral ring (n = 11), mitral valve abnormalities including parachute mitral valve, fused chordae, single papillary muscle (n = 10), and "typical" (Ruckman & Van Praagh) congenital mitral stenosis (n = 14). The LVOT obstruction features included subaortic stenosis (n = 16), valvar aortic stenosis (n = 7), bicuspid aortic valve (n = 24), and coarctation (n = 18). All 27 patients underwent 94 surgical procedures, including 22 mitral operations and 48 LVOT operations.

RESULTS

There were no operative deaths at the first operation. Mean follow-up was 4.7 +/- 4.4 years (range, 6 months to 15 years). There were three late deaths (11%). All late deaths were secondary to severe mitral valve disease. Overall 15-year actuarial survival was 89%. All surviving patients are in New York Heart Association functional class I or II.

CONCLUSIONS

Patients with Shone's anomaly are seen with a wide spectrum of major anatomic and hemodynamic abnormalities. A favorable outcome is possible for most. Operative mortality is adversely affected by the severity of mitral valve disease, the degree of left ventricular hypoplasia, and the need for multiple operative procedures.

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.

Risk factors for aortic valve dysfunction in children with discrete subvalvar aortic stenosis

Aortic regurgitation (AR) is a known complication of discrete subvalvar aortic stenosis (DSS), and its detection often triggers referral for surgery. However, risk factors for aortic valve dysfunction in children with DSS remain incompletely defined. The primary goal of this study was to determine independent risk factors for moderate or severe AR at mid-term follow-up in patients with DSS. Clinical records and echocardiograms of 220 patients with DSS (109 patients had DSS resection and 111 had no surgery) were analyzed. The primary outcome variable was AR grade (based on the width of the vena contracta) at latest follow-up. Age at diagnosis, gender, and duration of follow-up (median 7.2 years, range 1 to 20.4) did not differ significantly between medical and surgical patients. By multivariate analysis, independent risk factors for moderate to severe AR (n = 30) were older age at diagnosis of DSS (odds ratio [OR] for age > or =17 years 5.13, p = 0.024), previous balloon or surgical aortic valvuloplasty (OR 19.6, p <0.001), and a longer follow-up period (OR for 1-year increase 1.15, p = 0.032). Excluding patients with previous surgical or balloon aortic valvuloplasty, a higher maximal Doppler gradient was an independent risk factor for moderate to severe AR (OR for peak gradient > or =50 mm Hg 10.8, p = 0.001). Independent predictors of low-risk patients (none or trivial AR and peak gradient < or =30 mm Hg) included thin and mobile aortic valve leaflets (OR 7.86, p = 0.006) and an associated ventricular septal defect (OR 2.18, p = 0.019). These clinical and echocardiographic variables can be used to stratify risk of aortic valve dysfunction in patients with DSS and aid in timing of surgical resection.

Discrete subaortic stenosis in adults: increased prevalence and slow rate of progression of the obstruction and aortic regurgitation

OBJECTIVES

We sought to determine the prevalence and rate of progression of left ventricular outflow tract obstruction (LVOTO) and aortic regurgitation (AR) in adults with discrete subaortic stenosis (DSS).

BACKGROUND

Discrete subaortic stenosis is an uncommon form of LVOTO, with rapid hemodynamic progression in children, but the prevalence and rate of progression in adults have not been studied so far.

METHODS

The prevalence of DSS was determined in 2,057 consecutive adults diagnosed with congenital heart disease (CHD). The relationship between LVOTO on Doppler echocardiography and patient age was analyzed. Sequential changes in LVOTO and AR were determined for patients with two or more Doppler echocardiograms obtained with at least a two-year interval.

RESULTS

A total of 134 adults (mean age 31 +/- 17 years) were diagnosed with DSS. The prevalence was 6.5% for all adults with CHD. Sixty patients (44%) had other associated CHD. The mean age of 29 patients who had undergone an operation for DSS during their adult life (56 +/- 15 years) was significantly higher than that of 64 patients (27 +/- 13 years) who had not required a surgical intervention (p < 0.0001). A significant relationship between LVOTO and patient age (r = 0.61, p < 0.0001) was found: 21 +/- 16 mm Hg in patients <25 years old, 51 +/- 47 mm Hg for those between 25 and 50 years old, and 78 +/- 36 mm Hg for those >50 years old. The LVOTO increased from 39.2 +/- 28 to 46.8 +/- 34 mm Hg (p = 0.01) during a mean follow-up of 4.8 +/- 1.8 years in 25 patients. The slope of the change in LVOTO was 2.25 +/- 4.7 mm Hg per year of follow-up. Aortic regurgitation was detected by color Doppler imaging in 109 patients (81%), but it was hemodynamically significant in <20%. An increase in the mean degree of AR over time was not significant (baseline: 1.3 +/- 0.8; follow-up: 1.5 +/- 0.9; p = 0.096).

CONCLUSIONS

The prevalence of DSS is increasing in adults due to the greater number of repaired CHDs that develop into evolutive DSS. In contrast to infants and children, adults with DSS show a slow rate of LVOTO progression. Aortic regurgitation is a common but usually mild and nonprogressive consequence. The current indications for surgical intervention should be revised.

Subaortic membrane excision: Mid-term results

BACKGROUND

Subaortic membrane (SAM) is a form of fixed subaortic obstruction in which a fibrous membrane is located below the aortic valve.

AIM

To determine the role of surgical treatment for patients with a discrete SAM.

PATIENTS AND METHODS

The hospital records of 45 patients (age range: 2-23 years; median 8 years) undergoing surgery for SAM between 1990 and 1998 at the All India Institute of Medical Sciences, New Delhi, India, were analysed. Preoperative echocardiographically calculated gradients across the left ventricular outflow tract ranged from 50 to 154 mmHg (mean: 86.5 +/- 33.2 mmHg). Nine patients had trivial aortic regurgitation (AR), 10 had mild AR and five had moderate-severe AR. The left ventricular ejection fraction (LVEF) ranged from 20 to 68% (mean 48 +/- 15%). Nineteen patients had significant left ventricular dysfunction (LVEF <50%). Transaortic resection of SAM was done in all patients along with excision of a wedge-shaped segment of septal muscle underlying the membrane.

RESULTS

There were no early or late postoperative deaths. On follow up (up to 113 months), only four patients had gradients >30 mmHg. LVEF improved to 45-70% (mean 58 +/- 7.7%). AR reduced to mild in four patients and trivial in four patients, and did not progress further.

CONCLUSION

Resection of SAM carries long-term benefits. Routine septal myectomy appears to be associated with a low risk of recurrence.

Subvalvular Aortic Stenosis

Subvalvular aortic stenosis (SAS) is a congenital heart defect that causes fixed form of hemodynamically significant left ventricular outflow tract (LVOT) obstruction with progressive course. It has a spectrum of anatomy. It appears usually beyond infancy, causes left ventricular hypertrophy and myocardial dysfunction, and tends to involve the aortic and mitral valves in its progressive course. Although most of the patients are asymptomatic, careful monitoring is essential. Moderate to severe SAS requires surgical resection and septal myomectomy. There is a high rate of postoperative recurrence of the lesion. Recurrent lesions and the complex type of lesions with aortic valve involvement should have aortoseptoplasty (to enlarge the outflow tract) and Ross procedure (removal of the damaged aortic valve and placement of a pulmonary autograft in the aortic position and a pulmonary homograft in the pulmonary position).

Echocardiographic, morphologic, and geometric variations of the left ventricular outflow tract: possible role in the pathogenesis of discrete subaortic stenosis

Although the clinical features and natural course of discrete subaortic stenosis (DSS) are well defined, the etiology remains speculative. The purpose of this study was to identify the echocardiographic, morphologic, and geometric variations of the left ventricular outflow tract associated with DSS in children and to determine whether these variations have a role in the pathogenesis of DSS. The aortoseptal angle (ASA), mitral-aortic valve separation (MAS), and the size of the aortic annulus were determined in two groups of children. Group 1 comprised 11 patients with isolated DSS, who were compared with an age- and body surface area- (BSA) matched healthy children (Group 1A, n: 20). Group 2 comprised 10 patients with DSS and ventricular septal defect (VSD). Group 2 was compared with an age- and BSA-matched patients with isolated perimembranous VSD (Group 2A, n: 22). Measurements were carried out from previously recorded echocardiographic studies. The ASA was steeper (119.3 +/- 6.1 degrees vs 137.5 +/- 5.6 degrees , p < 0.001), and the MAS was wider (6.1 +/- 1.6 vs 3.2 +/- 0.7 mm, p < 0.001) in patients with isolated DSS than in healthy control subjects. Similar differences were found between patients in Group 2 and Group 2A; the ASA was steeper (122.2 +/- 6.5 degrees vs 141.3 +/- 5.0 degrees, p < 0.001), and the MAS was wider (5.8 +/- 1.5 vs 3.8 +/- 1.1 mm, p < 0.001). The size of the aortic annulus was not different among the four study groups. Although the MAS was significantly wider in patients with DSS, there was significant overlap in MAS between patients and controls. However, if an ASA < or = 130 degrees was chosen as a predictive variable, it was found to be a highly sensitive, specific, and positive predictive marker for the development of DSS. This study demonstrates that DSS is associated with a steeper ASA, and a wider MAS, in patients with or without associated VSD. These morphologic abnormalities, especially a steeper ASA, may be risk factors for the development of DSS.

Natural history and surgical outcomes for isolated discrete subaortic stenosis in children

OBJECTIVE

To document the natural history and surgical outcomes for discrete subaortic stenosis in children.

DESIGN

Retrospective review.

SETTING

Tertiary care paediatric cardiology centres.

PATIENTS

92 children diagnosed between 1985 and 1998.

MAIN OUTCOME MEASURES

Echocardiographic left ventricular outflow gradient (echograd), and aortic insufficiency (AI).

RESULTS

The mean (SEM) age at diagnosis was 5.3 (0.4) years; the mean echograd was 30 (2) mm Hg, with AI in 22% (19/87) of patients. The echograd and incidence of AI increased to 35 (3) mm Hg and 53% (36/68) (p < 0.05) 3.6 (0.3) years later. The echograd at diagnosis predicted echograd progression and appearance of AI. 42 patients underwent surgery 2.2 (0.4) years after diagnosis. Preoperatively echograd and AI incidence increased to 58 (6) mm Hg and 76% (19/25) (p < 0.05). The echograd was 26 (4) mm Hg 3.7 (0.4) years postoperatively, with AI in 82% (31/38) of patients. Surgical morbidities included complete heart block, need for prosthetic valves, and iatrogenic ventricular septal defects. Eight patients underwent reoperation for recurrent subaortic stenosis. The age at diagnosis of 44 patients followed medically and 42 patients operated on did not differ (5.5 (0.6) v 5. 0 (0.6) years, p < 0.05). However, the echograd at diagnosis in the former was less (21 (2) v 40 (5) mm Hg, p < 0.05) and did not increase (23 (2) mm Hg) despite longer follow up (4.1 (0.4) v 2.2 (0. 4) years, p < 0.05). The incidence of AI at diagnosis and at last medical follow up was also less (14% (6/44) v 34% (13/38); 40% (17/43) v 76% (19/25), p < 0.05).

CONCLUSIONS

Many children with mild subaortic stenosis exhibit little progression of obstruction or AI and need not undergo immediate surgery. Others with more severe subaortic stenosis may progress precipitously and will benefit from early resection despite risks of surgical morbidity and recurrence.

Resection of subaortic stenosis; can a more aggressive approach be justified?

OBJECTIVES

Discrete subaortic stenosis causes left ventricular outflow tract (LVOT) obstruction and often produces aortic regurgitation (AR) which alone may precipitate surgical intervention. Conventional resection relieves the obstruction, but the recurrence rate is high, and the AR is little changed as the thick fibrous membrane which extends onto the valve leaflets remains. We studied whether an aggressive surgical approach could reduce both the severity of AR and rate of recurrence of obstruction associated with discrete subaortic stenosis, and whether this aggressive approach could be justified.

METHODS

Between June 1992 and April 1996, 37 patients aged 0.5-35 years (median 7.5) underwent resection of a discrete subaortic membrane. Ten underwent re-operation for recurrent obstruction and eight followed previous ventricular septal defect closure. LVOT gradient was measured using the modified Bernoulli equation and AR was graded on a scale of 0-4 (0 = none, 4 = severe). Postoperative assessment was performed early (<7 days) and at mid-term (27.0 months; range 2-59 months).

RESULTS

There was significant improvement in AR from mild/moderate to none/trivial (P = 0.019) immediately postoperatively and LVOT gradient from 66.9+/-30.4 to 15.1+/-12.2 mmHg (P < 0.0001). By stepwise logistic regression preoperative gradient correlated significantly with postoperative mild/moderate AR (P = 0.015) and LVOT gradient (P = 0.0036). Preoperative mild/moderate AR also correlated with postoperative mild/moderate AR (P = 0.034). Five patients developed complete heart block, four undergoing reoperation for recurrent obstruction, and one preoperatively had right bundle branch block from previous ventricular septal defect repair. At mid-term follow-up there was no increase in AR or LVOT gradient (14.8+/-12.8 mmHg). Early post-operative AR was the strongest predictor of late mild/moderate AR (P = 0.02). Early post-operative gradient was a weaker predictor (P = 0.04). Pre-operative and early post-operative gradient were significant predictors of late gradient (P = 0.0038; <0.0001, respectively). No patient required reoperation for recurrent obstruction; one underwent late aortic valve replacement for severe AR.

CONCLUSIONS

An aggressive surgical approach to discrete subaortic stenosis produces excellent relief of obstruction and frees the valve leaflets, significantly reducing associated AR at early and mid-term follow-up with low morbidity for primary operation. Long-term follow-up is required to confirm whether this early benefit is maintained.

The surgical treatment of fixed subaortic stenosis: a clinical experience in Japan

We report herein the results of a retrospective study conducted on ten consecutive Japanese patients who underwent successful surgical relief of fixed subaortic stenosis between 1972 and 1994 at ages ranging from 8 months to 21 years, and followed for 3.6 years and 26 years. Associated cardiovascular defects were present in six patients, two had a history of infective endocarditis, a discrete fibrous ring was found in nine patients, and a redundant abnormal sheet was found in one. A stenotic structure was removed in nine patients and incised in one, while myotomy was additionally performed in one. There were no early complications or deaths. Cardiac catheterization revealed a significant decrease in the peak systolic pressure gradient from 84+/-22 mm Hg preoperatively to 32+/-22 mm Hg postoperatively (P = 0.0017). Reoperation of an aortic valve replacement with or without valvular annulus enlargement was required in four patients because of a small annulus with aortic insufficiency or infective endocarditis. Infective endocarditis was a major cause of late mortality (n = 1) and morbidity (n = 1), but the remaining eight patients have been asymptomatic. Thus, although this lesion is relatively rare in Japan, the typical discrete type may be more common than previously believed. While a relief operation is associated with low early mortality, the palliative aspect regarding pathology of the aortic valve should not be underestimated, including poor growth of the valve annulus, deterioration of aortic insufficiency, and infective endocarditis. The most appropriate operative procedure for reoperation remains to be evolved.

Use of three-dimensional echocardiography for analysis of outflow obstruction in congenital heart disease

To evaluate the feasibility and accuracy of 3-dimensional (3D) echocardiography in analysis of left and right ventricular outflow tract (LVOT and RVOT) obstruction, 3D echocardiography was performed in 28 patients (age 4 months to 36 years) with outflow tract pathology. Type of lesion and relation to valves were assessed. Length and degree of obstruction were measured. Three-D data sets were adequate for reconstruction in 25 of 28 patients; 47 reconstructions were made. In 13 patients with LVOT obstruction, 3D echocardiography was used to study subvalvular details in 8, valvular in 13, and supravalvular in 1. Four of these 13 patients had complex subaortic obstruction. In 12 patients with RVOT lesions, 3D echocardiography was used to study subvalvular details in 11, valvular in 12, and supravalvular in 2. Three-dimensional reconstructions were suitable for analysis in 100% of subvalvular LVOT, 77% valvular LVOT, 100% supravalvular LVOT, 100% subvalvular RVOT, 50% valvular RVOT, and 50% supravalvular RVOT. Twenty patients underwent operation, and surgical findings served as morphologic control for thirty-four 3D reconstructions (LVOT 17, RVOT 17). Operative findings revealed an accuracy at subvalvular LVOT of 100%, valvular LVOT 90%, supravalvular LVOT 100%, subvalvular RVOT 100%, valvular RVOT 100%, and supravalvular RVOT 100%. Quantitative measurements could adequately be performed. Three-D echocardiography is feasible and accurate for analyzing both outflow tracts of the heart. Particularly, generation of nonconventional horizontal cross sections allows a good definition of extension and severity of lesions.

Discrete subaortic stenosis: an acquired heart disease

OBJECTIVE

To determine the anatomic variables in the left ventricular outflow tract in patients with subaortic stenosis.

METHODS

Between 1982 and 1996, 36 patients were operated on with the 'discrete' form of subaortic stenosis (DSS). The mean time of follow up was 7.4 years with a range of 4 months-14 years. There were 25 male and 11 female patients. Mean age at operation was 7.1 years with a range of 9 months-47 years.

RESULTS

At the time of surgery, the mitral valve apparatus and interventricular septum were found to be rotated 60-90 degrees in a counterclockwise fashion with anterior displacement into the left ventricular outflow tract in 30 (83%) patients. Subaortic ridge resection with a deep septal myectomy was performed in 32 patients and the remaining four patients had subaortic ridge resection alone. The reoperation free rate at 5 and 10 years were 74+/-9% and 60+/-12%, respectively. Reoperations for recurrent disease were performed in 10 (27.7%) patients. No operative or late follow up deaths were encountered.

CONCLUSION

We conclude that DSS is an acquired disease due to a pre-existing anatomic alteration in the mitral valve apparatus and interventricular septum. In addition, recurrence rates are high and physicians should not be mislead by the benign nomenclature its name implies.

Benefits of early surgical repair in fixed subaortic stenosis

OBJECTIVES

We sought to determine whether early resection can improve outcome in fixed subaortic stenosis.

BACKGROUND

The diagnosis of subaortic stenosis (SAS) is often made before significant gradients occur. Whereas resection is the accepted treatment, it remains uncertain whether surgical intervention at this early stage can reduce the incidence of recurrence or influence the progression of aortic valve damage.

METHODS

Follow-up was available for 75 of 83 consecutive patients operated on for fixed SAS; the average duration of follow-up was 6.7 years. The lesion was discrete in 68 patients (91%) and of a tunnel type in 7, with associated ventricular septal defect in 28 (37%). All underwent transaortic resection.

RESULTS

There were no deaths. There were 18 recurrences of SAS in 15 patients (20%). Thirteen patients (17%) underwent 17 reoperations for recurrence or aortic valve disease. The cumulative hazard of recurrence was 8.9%, 16.1% and 29.4% +/- 2.3% (mean +/- SEM), and the hazard of events, including recurrence and reoperation, was 9.2%, 18.4% and 35.1% +/- 3.5% at 2, 5 and 10 years, respectively. Residual end-operative left ventricular outflow tract (LVOT) gradients (> 10 mm Hg, n = 8) and tunnel lesions were univariate predictors of recurrence (p = 0.0006 and p = 0.003, respectively). Multivariate predictors included higher preoperative LVOT gradient (p < 10(-4)) and younger patient age (p = 0.002). Only two recurrences (0.87 per 100 patient-years of follow-up) were noted in patients with a preoperative peak LVOT gradient < or = 40 mm Hg (n = 40), whereas higher gradients (n = 35) were associated with a greater than sevenfold recurrence rate (6.45 events per 100 patient-years, p = 0.002). The aortic valve required concomitant repair in 17 cases in the high gradient group (48.6%) but in only 8 in the low gradient group (20%, p = 0.018). Despite relief of the obstruction, progressive aortic regurgitation was noted at follow-up after 14 procedures in the high gradient group (40%) but after only 5 procedures in the low gradient group (12.5%, p = 0.014).

CONCLUSIONS

The data suggest that surgical resection of fixed subaortic stenosis before the development of a significant (> 40 mm Hg) outflow tract gradient may prevent recurrence, reoperation and secondary progressive aortic valve disease.

Multiple left heart obstructions (Shone's anomaly) with mitral valve involvement: long-term surgical outcome

BACKGROUND

The outcome of children with multilevel left heart obstructions (Shone's anomaly) is generally poor. Literature is scarce, consisting mainly of case reports. The mitral disease may be the predominant factor affecting outcome.

METHODS

Surgical results in 19 consecutive patients are presented, with a median follow-up of 8 years. Mitral stenosis was present in all, with parachute deformity in 12 patients. Supramitral rings were found in 9 patients. Other features included subaortic stenosis (15 patients), valvar aortic stenosis (9), bicuspid aortic valve (16), and coarctation (13 patients). The patients underwent 46 surgical procedures, including 18 mitral operations (9 replacements, 9 repairs).

RESULTS

There were three in-hospital (16%) and two late (10.5%) deaths. Of the 5 nonsurvivors, 4 patients (80%) had predominant mitral disease and moderate to severe pulmonary hypertension, versus 4 (28.5%) and 5 (36%) survivors, respectively (p = not significant). Valve repair was the final procedure in 9 survivors. The other 5 patients had repeated valve replacements (1), aortoventriculoplasty with valve replacements (2), or no mitral operation (2). Freedom from mitral reoperation was 78% (7 of 9 patients) after repair procedures and 43% (3 of 7 patients) after replacement. At follow-up, 10 patients (71.4%) are in New York Heart Association functional class I and the other 4 in class II and III. Six (43%) await reoperation due to recurrent aortic (4) or subaortic (1) stenosis and recoarctation (2). Echocardiography reveals mild mitral stenosis or regurgitation in 3 patients after repair (33%). Four are considered free of residual disease (21% of all).

CONCLUSIONS

Late outcome in Shone's anomaly seems to correlate with the predominance of mitral valve involvement and the degree of pulmonary hypertension. Valve repair is indicated whenever feasible and should be considered before the occurrence of pulmonary hypertension.

Posterior deviation of left ventricular outflow tract septal components without ventricular septal defect

OBJECTIVE

To describe 11 patients with narrowing of the left ventricular outflow tract caused by angular posterior deviation of both the outlet septum and the upper part of trabecular septum, which was diagnosed by cross sectional echocardiography in all and confirmed by angiocardiography in seven.

RESULTS

Four patients had a subaortic systolic pressure gradient ranging from 23 to 70 mm Hg by Doppler echocardiography; cardiac catheterisation showed a significant (60 and 104 mm Hg) systolic pressure gradient in two. In four cases aortic regurgitation and two tricuspid pouches were shown by Doppler echocardiography, angiocardiography, or both. Four cases had a ridge at the angulation point on echocardiographic examination. Three patients were operated on for systolic pressure gradients of the left ventricular outflow tract and one for severe aortic regurgitation. There was proliferation of collagen-rich fibrous tissue in the subendocardial region on histopathological examination of the myectomy material. A ventricular septal defect had been diagnosed previously by contrast echocardiography in one patient; thus ventricular septal defects may close spontaneously over a period of time including fetal life. A subaortic ridge was detected in one patient at follow up.

CONCLUSIONS

Deviation of the outlet and trabecular septa should be considered as a cause of ventricular outflow tract obstruction even when no ventricular septal defect is present.

Postoperative follow-up of fibromuscular subaortic stenosis

OBJECTIVES

This study attempted to determine whether early subaortic resection at lower levels of obstruction reduces the rate of recurrence of subaortic stenosis or reduces secondary damage to the aortic valve, or both.

BACKGROUND

Fibromuscular subaortic stenosis is a progressive condition, and at present it is unclear whether early operation reduces the recurrence rate along with decreasing the incidence of aortic insufficiency.

METHODS

Thirty-seven patients with fibromuscular subaortic stenosis and no other significant cardiac abnormality who underwent open subaortic resection were evaluated. The preoperative, early and late postoperative catheterization or echocardiographic findings as well as the operative reports were reviewed. The median age at operation was 6.4 years (range 1.1 to 17.3). The entire group has been followed up postoperatively for a median of 5.2 years (range 1.1 to 11). Mean systolic gradients across the left ventricular outflow tract were used for the purpose of this study.

RESULTS

There was a significant correlation between the preoperative mean systolic gradient and the incidence of preoperative aortic regurgitation and late postoperative aortic valve thickening as well as the incidence and degree of late postoperative aortic regurgitation. Late postoperative gradient and degree of aortic regurgitation correlated significantly with the follow-up interval. Aortic regurgitation was progressive in some patients despite subaortic resection. A preoperative mean gradient > 30 mm Hg provided a reasonable cutoff for the likelihood postoperatively of needing a reoperation, having a postoperative shelf, a thickened aortic valve, moderate aortic regurgitation or a gradient of > 10 mm Hg.

CONCLUSIONS

Our results suggest that although early subaortic resection may not reduce the rate of recurrence of fixed subaortic stenosis, it is likely to reduce acquired damage to the aortic valve.

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.