Fixed subaortic stenosis in the young: medical and surgical course in 83 patients

Perioperative and Anesthetic Considerations in Pediatric Valvar and Subvalvar Aortic Stenosis

Aortic stenosis (AS) is a common form of left ventricular outflow tract obstruction (LVOTO) in children with congenital heart disease. This review specifically considers the perioperative features of valvar (VAS) and subvalvar AS (subAS) in the pediatric patient. Although VAS and subAS share some clinical features and diagnostic approaches, they are distinct clinical entities with separate therapeutic options, which range from transcatheter intervention to surgical repair. We detail the pathophysiology of AS and highlight the range of treatment strategies with a focus on anesthetic considerations for the care of these patients before, during, and after intervention.

Valvular heart disease in congenital heart disease: a narrative review

Patients with congenital heart disease (CHD) are one of the fastest growing populations in cardiology, and valvular pathology is at the center of many congenital lesions. Derangements in valvular embryology lead to several anomalies prone to dysfunction, each with hemodynamic effects that require appropriate surveillance and management. Surgical innovation has provided new treatments that have improved survival in this population, though has also contributed to esotericism in patients who already have unique anatomic and physiologic considerations. Conduit and prosthesis durability are often monitored collaboratively with general and specialized congenital-focused cardiologists. As such, general cardiologists must become familiar with valvular disease with CHD for appropriate care and referral practices. In this review, we summarize the embryology of the semilunar and atrioventricular (AV) valves as a foundation for understanding the origins of valvular CHD and describe the mechanisms that account for heterogeneity in disease. We then highlight the categories of pathology from the simple (e.g., bicuspid aortic valve, isolated pulmonic stenosis) to the more complex (e.g., Ebstein's anomaly, AV valvular disease in single ventricle circulations) with details on natural history, diagnosis, and contemporary therapeutic approaches. Care for CHD patients requires collaborative effort between providers, both CHD-specialized and not, to achieve optimal patient outcomes.

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.

EDUCATIONAL SERIES IN CONGENITAL HEART DISEASE: Congenital left-sided heart obstruction

Congenital obstruction of the left ventricular outflow tract remains a significant problem and multilevel obstruction can often coexist. Obstruction can take several morphological forms and may involve the subvalvar, valvar or supravalvar portion of the aortic valve complex. Congenital valvar stenosis presenting in the neonatal period represents a spectrum of disorders ranging from the hypoplastic left heart syndrome to almost normal hearts. Treatment options vary dependent on the severity of the left ventricular outflow tract obstruction (LVOTO) and the variable degree of left ventricular hypoplasia as well as the associated lesions such as arch hypoplasia and coarctation.

When Is It Better to Wait? Surgical Timing and Recurrence Risk for Children Undergoing Repair of Subaortic Stenosis

Recurrence of subaortic stenosis (SAS) after surgery is common in children. The effects of patient characteristics and surgical timing on disease recurrence are largely unknown. We performed a retrospective study, assessing the relative effects of patient age and left ventricular outflow tract (LVOT) gradient on the need for reoperation for recurrent SAS. We included all children <20 years of age who underwent initial surgical resection of SAS at our center, January 2003-December 2013. Stratified logistic regression was performed, considering the effects of patient demographics, clinical characteristics, echocardiographic parameters, and operative technique, and clustering standard errors by surgeon. The multivariable model was used to simulate predicted probabilities of recurrent SAS for children at varying ages and baseline LVOT gradients. Sixty-three patients (38 males) underwent initial operation for SAS. Patients were followed for a median of 3.7 years (IQR 1.2-7.1). Twenty-one percent of patients (n = 13) underwent reoperation for SAS. Twelve were male. For every 10 mmHg increase in preoperative peak gradient in boys, the odds of reoperation for SAS doubled (OR 2.01, CI 1.5-2.72, p < 0.001), and for every additional 6 months of age, the odds of reoperation decreased by 14% (OR 0.86, CI 0.84-0.88, p < 0.001). Both younger age and higher preoperative outflow tract gradient are independently associated with risk of reoperation. Clinicians should consider the age and rate of LVOT gradient change-and not just the absolute gradient-in determining initial surgical timing.

Chordae Tendineae Rupture Resulting in Pulmonary Edema in a Patient with Discrete subvalvular Aortic Stenosis

This report concerns an apparently healthy elderly woman who presented with gradually worsening mitral regurgitation secondary to chordae tendineae rupture leading to pulmonary edema in the presence of discrete subvalvular aortic stenosis with a severe gradient reflecting the left ventricular outflow tract obstruction. The gradual worsening of heart failure took place parallel to the increase in severity of mitral regurgitation in a short period. The patient underwent successful mitral valve replacement with myectomy. Surgical inspection revealed rupture of the chordae tendineae to the posterior leaflets without any significant primary intrinsic disease of the mitral valve. The predominant mechanism of chordae tendineae rupture in this patient with discrete subvalvular aortic stenosis is a severe pressure gradient. It is suggested that increased awareness of chordae tendineae rupture as a cause of mitral regur gitation and the prompt use of appropriate diagnostic tools may facilitate the timely recogni tion of this potentially fatal, but treatable, cause of mitral regurgitation in patients with left ventricular outflow tract obstruction.

Echocardiography as a Predicting Method in Diagnosis, Evaluation and Assessment of Children with Subvalvar Aortic Stenosis

BACKGROUND:

Obstruction to the left ventricular outflow of the heart may be above the aortic valve (5%), at the valve (74%), or in the subvalvar region (23%). These anomalies represent 3 to 6% of all patients with congenital heart defects (CHD), and it occurs more often in males (male-female ratio of 4:1).

AIM:

The purpose of this study was to determine the sensitivity and specificity of transthoracic echocardiography in diagnosis of discrete subaortic membrane, to determine convenient time for surgical intervention, and for identifying involvement of the aortic valve by subaortic shelf.

MATERIAL AND METHODS:

A retrospective review of the medical records and echocardiograms of 18 patients [14 male (77%) and 4 female (23%)] with discrete subaortic membrane, aged 11 month to 12 years, with mean age of 5 years and 3 month, diagnosed at the Pediatric Clinic in Prishtina, during the period September, 1999 and December, 2010 were done.

RESULTS:

Four patients, in neonatal age were operated from critical coarctation of the aorta and, initial signs of congestive heart failure were presented. 2 of them were operated in Belgrade, Serbia and 2 in Lausanne, Switzerland.

CONCLUSION:

In all presented patients bicuspid aortic valve was noted, but none of them subaortic membrane was registered.

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.

Outcome in Children Operated for Membranous Subaortic Stenosis

Background:

The optimal surgical procedure for treatment of fibromembranous subaortic stenosis has been a subject of debate. We report our experience with patients treated for membranous subaortic stenosis using membrane resection alone and membrane resection plus aggressive septal myectomy.

Methods:

Patients followed in the pediatric cardiology clinic of a university hospital, who had undergone surgery for subaortic stenosis between 2002 and 2013 were reviewed. Recurrence of subaortic membrane, residual left ventricular outflow gradient, and aortic valve function were analyzed.

Results:

Forty-six patients underwent surgery for subaortic membrane. Of these, 19 had membrane resection plus aggressive septal myectomy, while 27 had membrane resection alone. Mean age at surgery for the membrane resection group was 7.7 ± 3.9 years and 10.9 ± 3.6 years for the membrane resection plus aggressive myectomy group. Preoperative subaortic gradient for the membrane resection group was 75.5 ± 26.7 mm Hg and 103.2 ± 39.7 mm Hg for the membrane resection plus aggressive myectomy group. The mean follow-up left ventricular outflow tract gradient was 42.3 ± 31.3 mm Hg in the membrane resection group, while it was 11.6 ± 6.3 mm Hg in the aggressive septal myectomy group. Nine patients from the membrane resection group had significant regrowth of the subaortic membrane during the follow-up period, while none of the aggressive septal myectomy group had detectable membrane on echocardiography. Seven of the nine patients with recurrence of the subaortic membrane underwent subsequent membrane resection plus aggressive septal myectomy. Intraoperative finding in all these redo cases was recurrence (growth) of a subaortic membrane.

Conclusion:

Aggressive septal myectomy offers less chance of recurrence, freedom from reoperation, and an improved aortic valve function. This is especially important in sub-Saharan settings where a chance of getting a second surgery is unpredictable.

Acquired discrete subaortic stenosis in solid organ transplant recipients

DSS is a rare acquired abnormality of the LV outflow tract in children and adults. DSS can be seen with or without associated congenital heart disease, but the mechanism of its emergence has been poorly understood. Here, we report two cases of DSS that developed after solid organ transplant in childhood. One patient underwent liver and kidney transplant at three yr of age for hereditary polycystic disease, and the other had liver transplant at three months of age due to uncontrollable high-output failure secondary to a large hepatic hemangioma. Both patients developed mild dynamic LV outflow tract obstruction and systemic hypertension soon after transplant, both of which resolved by the time of discharge. Transient LV hypertrophy was observed in both cases. Corticosteroids, cyclosporine A, and tacrolimus were used as initial immunosuppressants. Both patients developed DSS long after the regression of the initial dynamic LV outflow tract obstruction. Herein, we report DSS as an atypical late cardiovascular complication after solid organ transplant and postulate that transient post-transplant hyperdynamic LV outflow tract obstruction and chronic immunosuppressive treatment may lead to subendocardial remodeling resulting in a fibromuscular membranous ridge in susceptible subjects.

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.

Subaortic membrane late after surgical correction of tetralogy of Fallot

We herein report a rare case of subaortic stenosis in association with a previous tetralogy of Fallot (TOF) surgical repair, which was not taken into account as a differential diagnosis. Echocardiography plays a pivotal role in identification of this rare combination. Therefore, echocardiography should be performed periodically during follow-up of patients with surgically corrected TOF. Given the clinical complications that can result from subaortic stenosis (i.e., aortic regurgitation and infective endocarditis), early and aggressive management of this rare combination should be performed.

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.

Transthoracic echocardiography does not reliably predict involvement of the aortic valve in patients with a discrete subaortic shelf

BACKGROUND

A discrete subaortic membrane cannot only cause left ventricular outflow tract obstruction, but can grow onto the aortic valve leaflets. The late finding of this encroachment is aortic valve insufficiency or stenosis. Echocardiography is used to follow the progression of outflow tract obstruction, but its ability to show subaortic membrane encroachment onto the aortic valve is unclear. The purpose of this study is to determine the sensitivity and specificity of echocardiography for diagnosing whether a discrete subaortic membrane involves the aortic valve.

METHODS

A pre-operative determination of aortic valve involvement by a discrete subaortic membrane was obtained by review of the official pre-operative echocardiogram reading and a retrospective blinded review of the pre-operative echocardiogram by an independent echocardiographer. These findings were compared to the intra-operative findings.

RESULTS

A total of 48 consecutive patients underwent primary resection for isolated discrete subaortic membrane between October, 1995 and May, 2006. The pre-operative and blinded readings both predicted a statistically lower rate of aortic valve involvement - 35% in 11 of 31 patients and 31% in 10 of 31 patients, respectively - than found at surgery - 65% in 31 of 48 patients. The sensitivity and specificity of pre-operative echocardiography to diagnose aortic valve involvement is 35% and 76%. Overall survival was 100%. There were no strokes, re-operations for bleeding or wound infections, or need for a pacemaker.

CONCLUSION

Echocardiography is not sensitive in assessing whether a discrete subaortic membrane involves the aortic valve. Since the morbidity and mortality for discrete subaortic membrane resection is negligible, resection may be indicated at the time of diagnosis to minimise aortic valve impairment.

Hypertrophic cardiomyopathy presenting as restrictive cardiomyopathy: a case complicated by biventricular apical aneurysms and papillary fibroelastoma

This report describes a 45-year-old male patient with nonobstructive hypertrophic cardiomyopathy, biventricular apical aneurysms, and papillary fibroelastoma. Histology revealed muscle fiber disarray, interstitial fibrosis, and mural vessel changes. The wall of the aneurysms showed fat infiltration, and loss and replacement of muscle fibers with fibrous tissues. A review of the literature suggests that this case is the first reported experience with the three pathologies occurring in combination.

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.

Geometry of the left ventricular outflow tract in fixed subaortic stenosis and intact ventricular septum: An echocardiographic study in children and adults

OBJECTIVE

We compared the echocardiographic geometry of the preoperative and postoperative left ventricular outflow tract in children and adults with isolated fixed subaortic stenosis with age- and weight-matched controls to elucidate whether the geometry can be modified when surgical intervention is performed at a younger age.

METHODS

The mitral-aortic valve distance, aortic valve diameter, aorto-left ventricular septal angle, degree of aortic valve dextroposition, aortic valve-subaortic stenosis distance, width of left ventricular outflow tract, left ventricle wall thickness, and septal thickness were determined preoperatively and postoperatively in 21 patients and 21 controls. The measurements were indexed to body surface area. Patients were divided into 3 age groups: group 1 comprised 9 patients aged 1 to 10 years, group 2 comprised 8 patients aged 11 to 20 years, and group 3 comprised 4 patients aged 21 years or more.

RESULTS

Compared with controls, patients had a significantly wider mitral-aortic separation (group 1, P = .003; group 2, P = .02), a steeper aortoseptal angle (group 1, P = .02; group 3, P = .03), a smaller left ventricular outflow tract width (group 1, P = .003; group 2, P = .01), a marked aortic valve dextroposition (groups 1 and 3), an increased left ventricle wall thickness (group 1, P = .03), and an increased septal thickness (group 1, P = .01). There was a significant difference between preoperative and postoperative values in aortoseptal angle and left ventricular outflow tract width in patients up to 10 years of age (P = .02 and P = .01, respectively).

CONCLUSIONS

Hearts with isolated subaortic stenosis have abnormal left ventricular outflow tract geometry that postoperatively showed changes in left ventricular outflow tract width and aortoseptal angle. Compared with controls, the aortoseptal angle does not "normalize" when surgery is performed in older patients, suggesting that left ventricular outflow tract geometry may be remodeled in younger patients.

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.

Surgical treatment of subaortic obstruction in adolescent and adults: long-term follow-up

Subaortic stenosis (SAS) is a wide spectrum of anatomical derangements ranging from a discrete fibrous membrane to tortuous fibrous tunnel with or without aortic annulus hypoplasia. We have reviewed 88 patients undergoing surgery for SAS over a 15-year period. There were 47 male and 41 female patients with a mean age of 19.8 +/- 10.6 years (range 11 to 39). Fifty-eight patients had discrete subaortic membrane, and 30 patients had diffuse tunnel subvalvular stenosis. The mean systolic pressure gradients were found to be 86.5 +/- 31.4 mmHg (range 48 to 145 mmHg). Ten patients had mild and 13 patients had moderate-to-severe aortic insufficiency (AI) preoperatively. Nine patients had bicuspid aortic valve. Forty patients (45.4%) had associated cardiac lesions. Isolated membranectomy was performed in six patients. Membranectomy associated with septal myectomy was done in 52 patients. Fifteen patients of them associated hypoplasia of the aortic orifice necessitated aortic valve replacement (AVR) using the Konno-Rastan procedure. Fifteen patients with tunnel SAS and normal aortic valves underwent a combined approach for valve sparing, a modified Konno procedure with patch septoplasty. Also eight patients required AVR because of the severity of AI and five patients aortic reconstruction procedures. Aortic commissurotomy was performed to relief of stenosis in four patients. There were three early deaths (3.4%) and one late death (1.1%) all after the Konno-Rastan procedure. Eight patients (9.1%) had permanent conduction abnormalities. Postoperative left ventricle-aorta gradient was significantly decreased at early postoperative period (p < 0.001) and ranged from 10 to 25 mmHg (mean 14.1 +/- 4.3). Fourteen patients (16.5%) were reoperated for recurrent obstruction or progression of AI. The mean reoperation interval was 4.4 +/- 1.7 years (range 2 to 8 years). Five-year reoperation-free survival was 88.0 +/- 3.6% and 12.5-year reoperation-free survival was 75.5 +/- 7.0%. Our results of aggressive surgical approach of subvalvular aortic stenosis produces relief of obstruction and frees the valve leaflets, significantly reducing associated AI with long-term survival and long-term adequate relief of left ventricular outflow tract obstruction.

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.

Severe hypoplasia of the abdominal aorta and its branches in a patient and his daughter

We report the history of a patient and his daughter, both affected with hypoplasia of the abdominal aorta and its branches, leading to early and dramatic complications. In the index patient, renal ischaemia as a result of severe hypoplasia of the abdominal aorta and the origin of renal arteries led to progressive renal failure and end-stage renal disease at the age of 32 years. Other vascular abnormalities included hypoplasia of the celiac trunk (CT) and superior mesenteric artery (SMA). After a successful kidney transplantation at the age of 40 years, he eventually deceased following an episode of possibly ischaemic acute pancreatitis at 47 years. The patient's daughter suffered from an haemorrhagic stroke at the age of 7 years, which led to the discovery of severe hypertension caused by bilateral narrowing of renal arteries, as well as hypoplasia of CT, SMA, subclavian and pulmonary arteries. Biopsy of the narrowed renal artery of the daughter showed a particular form of fibrodysplasia characterized by an unusual fibrosis of the inner part of the media, just beneath the internal elastic lamina. To our knowledge, this is the first report of familial hypoplasia of the abdominal aorta. It might be the cardinal manifestation of a familial form of fibromuscular dysplasia (FMD). Interestingly, the histological lesions described in the daughter's renal artery differ from the classical form of medial FMD.

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).

Surgical management of complex and tunnel-like subaortic stenosis

BACKGROUND

Relief of primary or secondary subaortic stenosis (SAS) remains a surgical challenge. Heart block, aortic valve regurgitation and recurrent obstruction have been persistent problems.

METHODS

Forty six patients who underwent surgery for complex and tunnel-like SAS between January 1990 and November 1998 were reviewed. In 45 of the 46 patients SAS developed following repair of a primary congenital heart defect and only one patient presented with de novo tunnel-like SAS. Fifteen of the 45 patients had undergone repair of double-outlet right ventricle (DORV) and the remaining 30 had undergone repair of a variety of defects. The median age at the time of surgery was 5 years. The modified Konno procedure was performed in 15 patients, Konno procedure in three, Ross-Konno procedure in two and resection of the conal septum in 12 patients. Five patients with DORV underwent replacement of the intraventricular baffle and two patients underwent an aortic valve-preserving procedure in conjunction with mitral valve replacement.

RESULTS

There were no deaths. None of the patients had an exacerbation of aortic regurgitation and none developed complete heart block. The median follow-up was 3 years (range 1 month-8.5 years). Two patients developed recurrent SAS defined as a gradient of 40 mmHg or greater diagnosed by transthoracic echocardiography. Freedom from SAS at 1, 3 and 5 years was 100, 94 and 86%, respectively.

CONCLUSIONS

We favor the modified Konno procedure and conal resection to the Konno or the Ross procedure, since insertion of a prosthetic valve or homograft is avoided and aortic valve function is preserved. Excellent relief of tunnel-like SAS can be achieved without damage to the conduction tissue.

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.

Discrete subaortic stenosis: assessing adequacy of myectomy by transesophageal echocardiography

BACKGROUND

Membranectomy and myectomy are standard therapy for discrete subaortic stenosis (DS) and are associated with low rates of endocarditis, recurrence, and aortic insufficiency. Extensive myectomy increases risk of complications such as conduction tissue damage and iatrogenic ventricular septal defect (VSD).

MATERIALS AND METHODS

Forty-five adult patients with DS underwent operations in Gulhane Military Medical Academy. Exertional dyspnea was the principal symptom in 29 (64.4%) patients. Transesophageal echocardiography (TEE) was performed routinely in all patients to assess the length and depth of needed myectomy during the perioperative period. Aortic insufficiency (AI) was also noted preoperatively in 31 (68.9%) and a history of aortic valve endocarditis was present in 4 (8.9%) patients.

RESULTS

Myectomy was performed according to TEE measurements. An average of 10 mm in width, 10 mm in depth, and 2.3 mm in length of septal tissue was resected. The mean left ventricle-aorta peak systolic gradient decreased from 70.2+/-9.7 to 17.2+/-2.7 mmHg (p < 0.001). Aortic valve repair was performed in 8 (7.8%) patients and aortic valve replacement in 11 (24.4%) patients at the initial operation. Iatrogenic VSD did not occur in any of the patients. Average postoperative left ventricular outflow tract diameter was 21+/-1.5 mm. Temporary complete heart block occurred in three patients. There was an early residual gradient (36+/-8 mmHg) resulting from temporary hypercontraction that decreased (18+/-5 mmHg) in the first postoperative day.

CONCLUSIONS

Myectomy under perioperative TEE measurement is safe and effective in the treatment of DS. TEE-guided myectomy reduces complications such as complete heart block and iatrogenic VSD.

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.

Surgical treatment of subaortic stenosis: a seventeen-year experience

OBJECTIVE

The aim of the study was to analyze the long-term results of subaortic stenosis relief and the risk factors associated with recurrence and reoperation.

METHODS

One hundred sixty patients with subaortic stenosis underwent biventricular repair. Before the operation the mean left ventricle-aorta gradient was 80 +/- 35 mm Hg, 57 patients had aortic regurgitation, and 34 were in New York Heart Association functional class III or IV. Median age at repair was 10 years. For discrete subaortic stenosis (n = 120), 39 patients underwent isolated membranectomy, 67 underwent membranectomy with associated septal myotomy, and 14 underwent septal myectomy. Tunnel subaortic stenosis (n = 34) was treated by myotomy in 10 cases, myectomy in 12, septoplasty in 7, Konno procedure in 3, and apical conduit in 2. Aortic valve replacement was performed in 6 cases, mitral valve replacement in 2 cases, and mitral valvuloplasty in 4 cases.

RESULTS

There were 5 early (3.1%) and 4 late (4.4%) deaths. Within 3.6 +/- 3.3 years a recurrent gradient greater than 30 mm Hg was found in 42 patients (27%), 20 of whom had 26 reoperations. According to multivariable Cox regression analysis survival was influenced by hypoplastic aortic anulus (P =.01) and mitral stenosis (P =.048); recurrence and reoperation were influenced by coarctation and immediate postoperative left ventricular outflow tract gradients. At a median follow-up of 13.3 years, mean left ventricle-aorta gradient was 20 +/- 13 mm Hg. Relief of the subaortic stenosis improved the degree of aortic regurgitation in 86% of patients with preoperative aortic regurgitation. Actuarial survival and freedom from reoperation rates at 15 years were 94% +/- 1.3% and 85% +/- 6%, respectively.

CONCLUSION

Although surgical treatment provides good results, recurrence and reoperation are significantly influenced by previous coarctation repair and by the quality of initial relief of subaortic stenosis.

Modified Konno-Rastan procedure for subaortic stenosis: indications, operative techniques, and results

BACKGROUND

Diffuse or unresectable subaortic stenosis (SAS) necessitates an aggressive surgical approach for the elimination of left ventricular outflow tract obstruction. In this article we report our experience with the modified Konno-Rastan procedure, with inherent preservation of the native aortic valve and annulus, in the treatment of diffuse or unresectable SAS.

METHODS

Sixteen children (age range, 21 months to 18 years) underwent the modified Konno-Rastan procedure through either a transventricular (n = 12) or a transatrial approach (n = 4) to the conal septum. Indications for operation were recurrent SAS (n = 3), hypertrophic obstructive cardiomyopathy (n = 3), tunnel stenosis (n = 2), SAS related to a canal (n = 3), and SAS after ventricular septal defect closure (n = 5). Eleven patients had undergone previous procedures and 5 underwent the modified Konno-Rastan procedure as their primary operation.

RESULTS

The mean preoperative left ventricular outflow tract gradient of 50 +/- 17 mm Hg was reduced to 3 +/- 7 mm Hg (p < 0.001) after surgical repair. Postoperative complications included sternal infection (n = 1), heart block (n = 2), mediastinal bleeding (n = 1), and renal and cerebral ischemia (n = 1). There was 1 late postoperative death caused by pneumonia 2 years after operation (6.2% mortality rate). The mean follow-up period was 62 +/- 39 months and all patients had complete relief of preoperative symptoms and were in New York Heart Association class I. One patient underwent a successful redo modified Konno-Rastan procedure 7 years after the first operation for residual left ventricular outflow tract obstruction immediately below the aortic valve. One patient is awaiting reoperation for aortic incompetence unrelated to conal enlargement 1.5 years after the first procedure.

CONCLUSIONS

The modified Konno-Rastan procedure represents an excellent therapy for diffuse or unresectable SAS in patients with a normal aortic valve. In addition, it produces excellent results in a limited number of patients with hypertrophic obstructive cardiomyopathy, in whom the Morrow procedure traditionally has been performed. Although it usually is performed through a transventricular approach, the modified Konno-Rastan procedure also can be performed through a transatrial approach; this is particularly useful in patients who have had previous ventricular septal defect closure associated with SAS occurring proximal to the prosthetic patch.

Membranous subaortic stenosis presenting decades after surgical correction for tetralogy of Fallot

Subaortic stenosis is rare in the middle-aged adult. Its association with tetralogy of Fallot is extremely rare. We report two middle-aged patients, presenting three decades after surgical repair of tetralogy of Fallot, with the rare association of subaortic stenosis. The clinical presentation in each patient mimicked residual pulmonary stenosis and insufficiency, but echocardiography revealed subaortic stenosis with associated valvular aortic regurgitation.