The aortic root in supravalvular aortic stenosis: the potential surgical relevance of morphologic findings

A 3D scaling law for supravalvular aortic stenosis suited for stethoscopic auscultations

In this study a frequency scaling law for 3D anatomically representative supravalvular aortic stenosis (SVAS) cases is proposed. The law is uncovered for stethoscopy's preferred auscultation range (70-120 Hz). LES simulations are performed on the CFD solver Fluent, leveraging Simulia's Living Heart Human Model (LHHM), modified to feature hourglass stenoses that range between 30 to 80 percent (mild to severe) in addition to the descending aorta. For physiological hemodynamic boundary conditions the Windkessel model is implemented via a UDF subroutine. The flow-generated acoustic signal is then extracted using the FW-H model and analyzed using FFT. A preferred receiver location that matches clinical practice is confirmed (right intercostal space) and a correlation between the degree of stenosis and a corresponding acoustic frequency is obtained. Five clinical auscultation signals are tested against the scaling law, with the findings interpreted in relation to the NHS classification of stenosis and to the assessments of experienced cardiologists. The scaling law is thus shown to succeed as a potential quantitative decision-support tool for clinicians, enabling them to reliably interpret stethoscopic auscultations for all degrees of stenosis, which is especially useful for moderate degrees of SVAS. Computational investigation of more complex stenotic cases would enhance the clinical relevance of this proposed scaling law, and will be explored in future research.

Computed Tomographic Evaluation of Congenital Left Ventricular Outflow Obstruction

Congenital left ventricular outflow obstruction represents a multilevel obstruction with several morphological forms. It can involve the subvalvular, valvar, or supravalvular portion of the aortic valve complex, and may coexist. Computed tomography (CT) plays an important supplementary role in the evaluation of patients with congenital LVOT obstruction. Unlike transthoracic echocardiography and cardiovascular magnetic resonance (CMR) imaging, it is not bounded by a small acoustic window, needs for anaesthesia or sedation, and metallic devices. Current generations of CT scanners with excellent spatial and temporal resolution, high pitch scanning, wide detector system, dose reduction algorithms, and advanced 3-dimensional postprocessing techniques provide a high-quality alternative to CMR or diagnostic cardiac catheterization. Radiologists performing CT in young children should be familiar with the advantages and disadvantages of CT and with the typical morphological imaging features of congenital left ventricular outflow obstruction.

Surgical Repair of Supravalvar Aortic Stenosis in Association With Transverse and Proximal Descending Aortic Abnormalities

BACKGROUND

Supravalvar aortic stenosis (SVAS) may be an isolated defect of the proximal ascending aorta. However, more severe cases have extension of the arteriopathy into the transverse and proximal descending aorta. The purpose of this study was to review our experience with SVAS with and without aortic arch arteriopathy.

METHODS

This was a retrospective review of 58 patients who underwent surgical repair of SVAS. The median age at repair was 18 months. A total of 37 patients had Williams syndrome. A total of 31 (53%) patients had associated peripheral pulmonary artery stenosis and 23 (39%) had coronary artery ostial stenosis (CAOS).

RESULTS

A total of 37 of 58 (64%) patients had surgical repair of SVAS without the need for arch intervention while 21 (36%) patients had repair of the distal aortic arch. There were 3 (5.2%) operative deaths, 2 of whom had aortic arch involvement and one without arch involvement. There were 2 deaths after discharge from the hospital. Patients who needed arch surgery were more likely to have severe arch gradients compared to those without arch involvement (71% vs 30%, P < .05), were more likely to undergo concomitant procedures for peripheral pulmonary artery stenosis or CAOS (90% vs 62%, P < .05), and to have Williams syndrome (86% vs 51%, P < .05).

CONCLUSIONS

More than one-third of patients who had SVAS repair at our institution had procedures directed at the transverse or proximal descending aorta. Patients with arch involvement had more severe arch obstruction, required more concomitant procedures, and were more likely to have Williams syndrome.

Influence of Surgical Methods on Hemodynamics in Supravalvular Aortic Stenosis: A Computational Hemodynamic Analysis

We compared differences in the hemodynamic parameters of multiple surgical techniques for supravalvular aortic stenosis (SVAS). A three-dimensional model was reconstructed based on a patient's CT scan. Virtual McGoon, Doty, and Brom repairs were completed using computer-aided design (CAD). Hemodynamic parameters were calculated through computational fluid dynamics (CFD). The velocity profile and wall shear stress (WSS) showed the blood flow pattern. Energy loss (EL) and energy efficiency (EE) were calculated to estimate the cardiac workload. The perioperative blood flow ratio (BFR) of brachiocephalic vessels and coronary arteries was calculated. The preoperative flow velocity was abnormally high (> 5.0 m/s). High WSS was detected at the sinotubular junction (STJ), and its preoperative distribution in the aorta was uneven. High-speed flow disappeared after each of the three operations. The WSS distribution at the aortic root was consistent with the postoperative STJ structure of each operation. EL in the systolic phase decreased postoperatively (Original: 634 mW, McGoon: 218 mW, Doty: 278 mW, Brom: 255 mW). No significant difference in brachiocephalic BFR was detected among the different techniques. A slightly increased coronary BFR (Original: 7.56%, McGoon: 7.99%, Doty: 8.55%, Brom: 8.89%) was detected. McGoon, Doty, and Brom repair each effectively restored stable blood flow and greatly improved EE. The best WSS distribution and coronary blood supply were achieved after Brom repair due to its ability to reconstruct the symmetrical aortic root structure. CFD combined with a virtual operation is a promising method in surgical planning and optimization for SVAS.

Supravalvar aortic stenosis: Imaging characteristics and associations on multidetector computed tomography angiography

AIM

To evaluate the imaging features and associations in patients with supravalvar aortic stenosis on multidetector computed tomography (CT) angiography.

MATERIALS AND METHODS

We retrospectively reviewed all CT angiography studies performed for evaluation of congenital heart diseases at our institution through the period from January 2014 to June 2020. Cases with supravalvar aortic stenosis were identified and classified as syndromic and nonsyndromic based on history, physical examination, and relevant investigations. The type and extent of vascular involvement and associated cardiovascular abnormalities were characterized.

RESULTS

Supravalvar aortic stenosis was identified in 26/3926 (0.66%) patients (22 males and 4 females; Age range: 2 months to 20 years). Discrete stenosis was seen in 14/26 (53.8%) patients, while diffuse involvement of the ascending aorta to varying degrees was seen in the remaining 12 (46.2%) patients. About 15/26 (57.7%) patients had pulmonary involvement at some level, namely, infundibular, valvar, supravalvar, or peripheral pulmonic stenosis while 15/26 (57.7%) patients had coronary arterial involvement either in the form of stenosis, occlusion, or ectasia. Aortic valvular abnormality including thickening, partial fusion, and adhesion of leaflet edges to the sinutubular junction causing reduced coronary inflow was seen in 15/26 (57.7%) patients. Associated ventricular septal defect, patent ductus arteriosus, and mitral valvular prolapse were seen in four (15.4%), five (19.2%), and two (7.7%) patients respectively.

CONCLUSION

Supravalvar aortic stenosis is a rare abnormality showing associated pulmonary arterial involvement, coronary arterial involvement, aortic valvular abnormalities, and associated congenital cardiac defects in the majority of cases, which may influence surgical outcomes.

Left Ventricular Outflow Tract Gradient Is Associated With Coronary Artery Obstruction in Children With Williams-Beuren Syndrome

OBJECTIVES

Patients with Williams-Beuren syndrome are associated with a high risk of hemodynamic collapse during sedation and/or anesthesia, presumably due to occult coronary obstruction. The objective of this study was to determine the association between transthoracic echocardiogram findings and the presence of coronary obstruction to examine if coronary obstruction can be predicted by transthoracic echocardiogram before anesthesia.

DESIGN

Retrospective data analysis of patients with Williams-Beuren syndrome who underwent transthoracic echocardiogram, cardiac catheterization, and/or surgical interventions to determine the correlation between echocardiogram findings and the presence of coronary obstruction determined by cardiac catheterization and/or surgery.

SETTING

Single-center university teaching hospital.

PARTICIPANTS

The study included 49 patients with Williams-Beuren syndrome who underwent transthoracic echocardiogram, cardiac catheterization, and/or surgical interventions.

MEASUREMENTS AND MAIN RESULTS

The only variable associated with coronary artery obstruction was the maximum instantaneous gradient (MIG) across the left ventricular outflow tract (LVOT) on a transthoracic echocardiogram. LVOT MIG ≥ 75 mmHg as the optimal cutoff value was associated with coronary artery obstruction (area under the curve 0.659, odds ratio 6.71, 95% CI 1.31-34.35, p = 0.022).

CONCLUSION

LVOT gradient can serve as a good predictor of the presence of coronary obstruction in patients with Williams-Beuren syndrome.

Coronary artery bypass grafting in children for atheromatous and non-atheromatous lesions

Coronary artery involvement in children is an uncommon but well-recognized clinical entity. It is an important cause for sudden cardiac death in children. Diagnosis requires a high index of suspicion since it has serious consequences when missed. Presentation of coronary artery abnormality is very variable due to congenital as well as acquired aetiology. In this review, we have described the different causes that require coronary artery bypass grafting in children and their pathogenesis. The nuances of conduit selection, graft behaviour in children, patency rates and long-term outcomes in children undergoing coronary artery bypass have also been discussed.

Avoidance of malignant arrhythmia caused by displacement of the right coronary artery ostium in surgical correction of supravalvular aortic stenosis

Objective

This study was performed to identify the effects of different surgical approaches on the right coronary artery ostium in patients with congenital supravalvular aortic stenosis (SVAS) and to determine how to avoid surgically induced right coronary artery occlusion.

Methods

The surgical techniques and outcomes of 91 patients who underwent surgical treatment of SVAS from 2008 to 2015 in our institution were retrospectively reviewed to identify the causes of early death, reoperation, and extracorporeal membrane oxygenation (ECMO) support.

Results

Four perioperative deaths (Doty’s technique, n = 4), six cases of ECMO support (Doty’s technique, n = 4; Brom’s technique, n = 1; McGoon’s technique, n = 1), and eight reoperations (Doty’s technique, n = 5; Brom’s technique, n = 2; McGoon’s technique, n = 1) occurred. In cases of reoperation, adjustment of the shape and position of the right coronary sinus patch relieved the malignant arrhythmia.

Conclusion

Different surgical techniques have different effects on the right coronary artery. The shape of the patch inserted into the right coronary sinus should be carefully clipped to avoid distortion and ischemia of the right coronary artery.

Cardiovascular disease in Williams syndrome

PURPOSE OF REVIEW

Williams syndrome is a multisystem disorder seen with some regularity at most pediatric centers and usually fairly often at larger centers. Cardiovascular abnormalities, because of elastin deficiency, are the leading cause of morbidity and mortality in patients with Williams syndrome. The present article presents a review of the most recent developments regarding the cardiovascular issues in Williams syndrome.

RECENT FINDINGS

Cardiovascular abnormalities occur in 80% of patients with Williams syndrome, the majority of which are arterial stenoses. The stenoses seen in Williams syndrome now appear to arise from deficient circumferential arterial growth. Pharmacological therapies aimed at improving the vascular stenoses have shown some promise in animal models. Surgical outcomes for supravalvar aortic stenosis are good at most centers. Transcatheter interventions are largely ineffective in Williams syndrome. Multilevel surgical pulmonary artery reconstruction has excellent results for peripheral pulmonary artery stenosis. Periprocedural risk stratification and management algorithms may decrease the risk of cardiovascular complications.

SUMMARY

Cardiovascular abnormalities are a major determining factor in the clinical picture and trajectory of patients with Williams syndrome. Advances in surgical techniques, medical therapeutic options, and periprocedural management hold promise for significant improvements in the cardiovascular outcomes of these patients.

Williams Syndrome and Anesthesia for Non-cardiac Surgery: High Risk Can Be Mitigated with Appropriate Planning

Patients with Williams syndrome are considered at high risk for anesthesia-related adverse events. At our institution, all William syndrome patients undergoing cardiac surgical, cardiac catheterization/interventional procedures, and cardiac imaging studies are cared for by cardiac anesthesiologists. All William syndrome patients undergoing non-cardiac surgical, interventional, or imaging studies are cared for by main operating room pediatric anesthesiologists with consultative input from a cardiac anesthesiologist. We reviewed our experience with 75 patients undergoing 202 separate anesthetics for 95 non-cardiac procedures and 107 cardiac procedures from 2012 to 2016. The mean age was 7.5 ± 7.0 years and the mean weight was 22.3 ± 17.0 kg. One hundred and eighty-seven patients had a general anesthetic (92.6%). Medications used included etomidate in 26.2%, propofol in 37.6%, isoflurane in 47.5%, and sevoflurane in 68.3%. Vasopressors and inotropes were required including calcium (22.8%), dopamine (10.4%), norepinephrine (17.3%), phenylephrine (35.1%), vasopressin (0.5%), and ephedrine (5.4%). The median length of stay after anesthesia was 2.8 days (range 0-32). No adverse events occurred in 89.6% of anesthetics. There were two cases of cardiac arrest, one of which required extracorporeal life support for resuscitation. Of the non-cardiac surgical procedures, 95.7% did not have a cardiovascular adverse event. Patients with Williams syndrome are at high risk for anesthesia, especially when undergoing cardiac procedures. The risk can be mitigated with appropriate planning and adherence to the hemodynamic goals for non-cardiac surgical procedures.

Brom Aortoplasty for Supravalvular Aortic Stenosis

BACKGROUND

Controversy remains regarding the optimal surgical approach for children with supravalvular aortic stenosis (SVAS).

METHODS

Since 1997 we have used Brom three-patch aortoplasty for patients with SVAS. We prefer computed tomography (CT) imaging for preoperative evaluation rather than cardiac catheterization as it avoids the well-known morbidity of general anesthesia. The purpose of this study was to present our intermediate-term results of this strategy.

RESULTS

Twenty consecutive patients with SVAS were treated with Brom aortoplasty. Mean age was 3.7 ± 5.9 years (median, 1.5 years). Twelve patients had Williams syndrome. Ten patients had preoperative advanced medical imaging (seven CT, three magnetic resonance imaging) and did not have cardiac catheterization. Mean times for cardiopulmonary bypass and cross-clamp were 172 ± 29 minutes and 110 ± 21 minutes, respectively. Ten patients had simultaneous pulmonary artery stenosis patching. Median length of stay was seven days. There was no operative or late mortality. Mean follow-up was 6 ± 5 years. There were no reoperations on the aortic root. Fifteen patients had mild or less aortic insufficiency (AI) and two had moderate AI. One patient who had infant balloon dilation of the aortic valve and postoperative subacute bacterial endocarditis had moderate-to-severe AI and aortic stenosis (AS). One patient had moderate residual SVAS; all others had no AS. No patients had late coronary insufficiency.

CONCLUSION

Brom aortoplasty promotes restoration of normal aortic root geometry and relief of coronary ostial stenosis, which is important in preventing myocardial ischemia. Computed tomography imaging is our preferred diagnostic modality. Intermediate-term outcomes are excellent with no recurrent SVAS, coronary events, or reoperations on the aortic valve.

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.

Surgical Correction of Supravalvar Aortic Stenosis: 52 Years' Experience

OBJECTIVES

Supravalvar aortic stenosis (SVAS) is a rare congenital anomaly. The "single-patch technique," "'two sinus augmentation with an inverted Y-patch" (both nonsymmetrical corrections), "three-patch technique," and the "slide aortoplasty" (both symmetrical corrections) are the techniques implemented by the majority of surgeons for the correction of SVAS. In the few studies that compared these techniques, no technique was shown to be superior over another. The aim of the present study is to review the 52-year experience with the surgical correction of SVAS in two of four congenital cardiothoracic surgical centers in the Netherlands.

METHODS

We retrospectively reviewed all patient files of those who underwent an operation to correct their SVAS, between 1962 and 2014 in our centers. Patients were divided according to their operating technique. These groups were compared using the end points freedom from reoperation and mortality.

RESULTS

A total of 49 patients were included, 23 (46.9%) patients in the nonsymmetrical group and 26 (53.1%) patients in the symmetrical group. Survival after 20 years in the nonsymmetrical group was 80% (standard error [SE]: 0.091) and in the symmetrical group was 85% (SE: 0.085; P = .163). Freedom from reoperation after 20 years in the nonsymmetrical group was 88% (SE: 0.079) and in the symmetrical group was 71% (SE: 0.107; P = 0.313).

CONCLUSION

In this patient group, there is no significant difference in survival and freedom from reoperation between the different surgical techniques for SVAS repair. Compared to the survival in the general population, the survival of SVAS patients is remarkably low. Apparently, SVAS is not a benign disease and probably patients should be followed more closely for the rest of their lives.

Fixed left ventricular outflow tract obstruction mimicking hypertrophic obstructive cardiomyopathy: pitfalls in diagnosis

We present a case series that highlights the diagnostic challenges with left ventricular hypertrophy (LVH) and left ventricular outflow tract obstruction (LVOTO). Fixed structural lesions causing LVOTO with secondary LVH may mimic hypertrophic obstructive cardiomyopathy (HOCM). Management of these two entities is critically different. Misdiagnosis and failure to recognize fixed left ventricular outflow tract (LVOT) lesions may result in morbidity as a result of inappropriate therapy and delay of definitive surgical treatment. It is thus necessary to identify the correct type and level of obstruction in the LVOT by careful correlation of clinical examination, Doppler evaluation, and advanced imaging findings.

Perioperative morbidity in children with elastin arteriopathy

BACKGROUND

Children with elastin arteriopathy (EA), the majority of whom have Williams-Beuren syndrome, are at high risk for sudden death. Case reports suggest that the risk of perioperative cardiac arrest and death is high, but none have reported the frequency or risk factors for morbidity and mortality in an entire cohort of children with EA undergoing anesthesia.

AIM

The aim of this study was to present one institution's rate of morbidity and mortality in all children with EA undergoing anesthesia and to examine patient characteristics that pose the greatest risk.

METHODS

We reviewed medical records of children with EA who underwent anesthesia or sedation for any procedure at our institution from 1990 to 2013. Cardiovascular hemodynamic indices from recent cardiac catheterization or echocardiography were tabulated for each child. The incidence, type, and associated factors of complications occurring intraoperatively through 48 h postoperatively were examined.

RESULTS

Forty-eight patients with confirmed EA underwent a total of 141 anesthetics. There were seven cardiac arrests (15% of patients, 5% of anesthetics) and nine additional intraoperative cardiovascular complications (15% of patients, 6% of anesthetics). Extracorporeal life support was initiated in five cases. There were no perioperative deaths. All children having a cardiac arrest or complication were <3 years old and had biventricular outflow tract obstruction (BVOTO). Subgroup analysis demonstrated high rates of cardiac arrest in two groups: children with BVOTO (44%) and age <3 years old (21%).

CONCLUSIONS

We have confirmed that the rate of cardiac arrest and complications is significantly elevated in children with EA undergoing anesthesia. Children <3 years old and with BVOTO were at the greatest risk in our population.

CHD associated with syndromic diagnoses: peri-operative risk factors and early outcomes

CHD is frequently associated with a genetic syndrome. These syndromes often present specific cardiovascular and non-cardiovascular co-morbidities that confer significant peri-operative risks affecting multiple organ systems. Although surgical outcomes have improved over time, these co-morbidities continue to contribute substantially to poor peri-operative mortality and morbidity outcomes. Peri-operative morbidity may have long-standing ramifications on neurodevelopment and overall health. Recognising the cardiovascular and non-cardiovascular risks associated with specific syndromic diagnoses will facilitate expectant management, early detection of clinical problems, and improved outcomes--for example, the development of syndrome-based protocols for peri-operative evaluation and prophylactic actions may improve outcomes for the more frequently encountered syndromes such as 22q11 deletion syndrome.

Coronary Artery Involvement of Williams Syndrome in Infants and Surgical Revascularization Strategy

Williams syndrome (WS) is a genetic disorder due to deficiency of elastin gene expression. It is characterized by typical somatic abnormalities and a wide range of cardiovascular malformations. Coronary artery involvement is a frequent finding of the syndrome, particularly in those patients with severe supravalvular aortic stenosis. We present the case of an 11-month-old infant affected by WS who developed severe coronary artery disease 2 months after the surgical repair of supravalvular aortic stenosis. The clinical picture and successful surgical revascularization strategy is also described.

Severe Congenital Obstruction of the Left Main Coronary Artery Coexisting With Supravalvular Aortic Stenosis in Williams Syndrome

Congenital obstruction of the left main coronary artery is a complicating feature of supravalvular aortic stenosis. We describe an eight-month-old female patient with Williams syndrome, supravalvular aortic stenosis, and branch pulmonary artery stenosis, with concomitant anomaly of severe obstruction of the left coronary artery orifice.

Extracorporeal cardiopulmonary resuscitation for breath-holding spells followed by cardiac arrest due to left main coronary artery stenosis

Non-syndromic congenital supravalvular aortic stenosis (SVAS) leads to ventricular hypertrophy and increased oxygen consumption, and when combined with other factors reduces coronary blood flow, potentially resulting in myocardial ischemia and sudden cardiac death. While the anatomic obstruction of coronary circulation is as common in non-syndromic SVAS as in Williams syndrome, it often remains unacknowledged. Extracorporeal membrane oxygenation (ECMO) is an elective procedure that can be used to support patients with cardiac arrest during diagnosis as a way to reduce cardiopulmonary load in preparation for surgery or further treatment. In this report, we describe the rare case of an infant with severe SVAS and mild valvular pulmonary and left main coronary artery stenosis, as well as breath-holding spells. After multiple cardiac arrests, the infant underwent diagnostic catheter angiography on ECMO and had the pathology surgically corrected.

Williams-Beuren syndrome: computed tomography imaging review

Williams-Beuren syndrome (WBS) affects young infants and children. The underlying etiopathogenesis of this rare disease is due to the mutation of the elastin gene that is responsible for the elasticity of the arterial wall. As a result of inadequate elastin production, the major systemic arteries become abnormally rigid and can be manifested by an impediment to the blood flow. The most common cardiovascular abnormalities encountered in WBS are supravalvular aortic stenosis, pulmonary arterial stenosis, and mitral valve prolapse. Less frequently observed cardiovascular abnormalities include coarctation of the aorta, ventricular septal defect, patent ductus, subaortic stenosis, and hypertrophic cardiomyopathy. Coronary artery stenosis and severe impediment to the bi-ventricular outflow as a result of supravalvular aortic and pulmonary artery stenosis predispose patients to sudden death. Patients with progressed arterial stenosis and severe stenosis are likely to require intervention to prevent serious complications. Rarely, imaging findings may precede clinical presentation, which allows the radiologist to participate in the patient care. However, to be more prudent, the radiologist must be accustomed to the imaging characteristics of WBS as well as the patient's clinical information, which could raise the suspicion of WBS. We performed a retrospective analysis of all the available images from patients diagnosed with WBS in last 4 years at our institution, and present key imaging findings along with a review of the literature to summarize the clinically relevant features as demonstrated by multidetector computed tomography in WBS. Cross-sectional imaging plays a vital role in the diagnosis of WBS cases with equivocal clinical features. MDCT evaluation of complex cardiovascular abnormalities of WBS including coronary artery disease is feasible with modern MDCT scanners and in the future, this approach could provide accurate information for planning, navigation, and noninvasive assessment of the secondary arterial changes in WBS and thus reducing the dependence upon invasive contrast catherization techniques.

Postcardiotomy mechanical circulatory support in two infants with williams' syndrome

Supravalvar aortic stenosis (SVAS) in patients with Williams' syndrome is often accompanied by coronary, pulmonary, and even myocardial lesions and therefore associated with increased perioperative morbidity and mortality. Extracorporeal membrane oxygenation (ECMO) provides reliable short-term mechanical circulatory support to patients, especially young, in acute postoperative cardiac failure when conventional means are ineffective. The incorporation of centrifugal pumps in these systems has made their use more efficient and less traumatic. We describe our experience of using the Levitronix CentriMag pump in two patients with Williams' syndrome who underwent surgical correction of supravalvular aortic stenosis.

Supravalvar aortic stenosis: current surgical approaches and outcomes

Supravalvar aortic stenosis (SVAS) is a congenital anomaly characterized by a discrete or diffuse narrowing of the ascending aorta. It may also be associated with right-ventricular outflow tract obstruction, aortic valve pathology and coronary ostial stenosis. While present in both familial and sporadic forms, it demonstrates a strong association with William-Beuren syndrome, both being anomalies associated with defects in the elastin gene. In this article, the authors have discussed the etiology, morphology, clinical presentation and genetic basis of SVAS. Various surgical approaches, both conventional and recent, have been discussed and demonstrated with the aid of diagrams. Single-, two- and three-sinus methods have been presented, along with a comparative analysis of early results, associated procedures, late mortality and reoperation. In conclusion, the authors have described their institutional experience of more than 40 years in the surgical management of SVAS.

Outcome of surgical correction of congenital supravalvular aortic stenosis with two- and three-sinus reconstruction techniques

BACKGROUND

Several surgical techniques for the treatment of congenital supravalvular aortic stenosis have been developed, yet there is no consensus about the optimal approach. We reviewed our institutional experience with 2- and 3-sinus reconstruction techniques.

METHODS

Thirty-eight patients operated on for supravalvular aortic stenosis between 1987 and 2012 in our institution were analyzed retrospectively. Eight patients (21%) were infants and in 5 (13.2%) diffuse stenosis was present. Mean peak pressure gradient was 86.1±28.7 mm Hg preoperatively. Surgical procedures included single-patch enlargement (McGoon, n=3), inverted bifurcated-patch aortoplasty (Doty, n=22), 3-sinus patch augmentation (Brom, n=8), and autologous slide aortoplasty (n=5). Major concomitant procedures were performed in 10 patients (26.3%).

RESULTS

Early mortality was 2.6%. Follow-up continued for a median of 7.5 years (range 3 weeks to 22 years). Overall survival estimates were 94% and 90% and overall freedom from reoperation was 83% at 5 and 20 years, respectively. No differences were found between surgical techniques in respect to survival, clinical course, hemodynamic outcome, or freedom from reoperation rates. A significantly worse outcome in regard to survival and reoperation rates was observed in infants.

CONCLUSIONS

Our study demonstrates equally good results for the repair of supravalvular aortic stenosis with both 2- and 3-sinus reconstruction. No evidence of a superior outcome for 3-sinus reconstruction techniques was found. Operation in infancy is an important factor associated with unfavorable outcome.

Supravalvular aortic stenosis: elastin arteriopathy

Supravalvular aortic stenosis is a systemic elastin (ELN) arteriopathy that disproportionately affects the supravalvular aorta. ELN arteriopathy may be present in a nonsyndromic condition or in syndromic conditions such as Williams-Beuren syndrome. The anatomic findings include congenital narrowing of the lumen of the aorta and other arteries, such as branches of pulmonary or coronary arteries. Given the systemic nature of the disease, accurate evaluation is recommended to establish the degree and extent of vascular involvement and to plan appropriate interventions, which are indicated whenever hemodynamically significant stenoses occur. ELN arteriopathy is genetically heterogeneous and occurs as a consequence of haploinsufficiency of the ELN gene on chromosome 7q11.23, owing to either microdeletion of the entire chromosomal region or ELN point mutations. Interestingly, there is a prevalence of premature termination mutations resulting in null alleles among ELN point mutations. The identification of the genetic defect in patients with supravalvular aortic stenosis is essential for a definitive diagnosis, prognosis, and genetic counseling.

Comparison of electrocardiographic QTc duration in patients with supravalvar aortic stenosis with versus without Williams syndrome

Cardiovascular abnormalities in Williams syndrome (WS) are largely attributable to elastin haploinsufficiency resulting from a large deletion of the elastin-containing region on chromosome 7q11.23. The risk of sudden death in patients with WS is 25- to 100-fold greater than that in the general population. The corrected QT (QTc) interval is prolonged in 14% of patients with WS. Patients with nonsyndromic supravalvar aortic stenosis (NSVAS) have elastin mutations resulting in elastin haploinsufficiency and a vascular phenotype nearly identical to that of WS. No previous studies have evaluated the QTc duration in NSVAS. A retrospective review of all electrocardiograms (ECGs) performed on consecutive patients with NSVAS at Arkansas Children's Hospital from January 1, 1985 to January 1, 2012 was completed. ECGs with nonsinus rhythm or unmeasurable intervals were excluded. The ECGs were read by 1 reader who was unaware of previous readings. A QTc interval of ≥460 ms was defined as prolonged. The NSVAS cohort was compared to previously published WS and control groups using the mixed model for continuous electrocardiographic variables and the generalized estimating equation for binary indicators for prolonged QTc. The generalized estimating equation used bootstrapping with 1,000 replicates. A total of 300 ECGs (median 6, range 1 to 27) from the 35 identified patients with NSVAS met the inclusion criteria. A total of 482 ECGs from patients with WS and 1,522 ECGs from controls were included. The mean age of the patients with NSVAS at ECG was 7.3 ± 6.9 years; 64% were male. The mean QTc duration was 409 ± 20 ms in the NSVAS group, 418 ± 17 ms in the control group (p <0.001), and 436 ± 27 ms in the WS group (p <0.001 compared to the control group). The prevalence of QTc prolongation was 0.3% in the NSVAS group, 2.0% in the control group (p <0.001), and 14.8% in the WS group (p <0.001 compared to controls). No patients with NSVAS died. In conclusion, cardiac repolarization is normal in patients with NSVAS. Elastin haploinsufficiency does not appear to be the etiology of QTc prolongation in patients with WS. The possible contribution of other genes on 7q11.23 to QTc prolongation in WS should be investigated.

A family with a new elastin gene mutation: broad clinical spectrum, including sudden cardiac death

Supravalvular aortic stenosis is associated with the Williams-Beuren syndrome, but it also occurs in a non-syndromatic congenital form. An elastin gene mutation of chromosome 7q11.23 is responsible in both cases. The vascular features are identical. These patients have a higher risk of sudden death, particularly when undergoing diagnostic or surgical procedures. We report the account of a family with a new mutation in the elastin gene. Screening over three generations revealed eight affected individuals. The cardiac and vascular malformations ranged from mild asymptomatic supravalvular aortic stenosis and isolated dysplastic atrioventricular valves to diffuse arterial hypoplasia. Two infants presented arteries affected at multiple locations, including the left coronary artery. Both died of sudden cardiac death and myocardial ischaemia, one while under general anaesthesia for cardiac catheterisation, and the other perioperatively. We discuss the pathophysiological aspects in these patients that deserve consideration before any general anaesthesia is administered.

Supravalvar aortic stenosis in infancy

Supravalvar aortic stenosis (SVAS) is a rare anomaly of the aortic root caused by a genetically based deficiency in elastin production. Concomitant primary and secondary cardiovascular lesions complicate surgical management and impact early and late outcomes. Because SVAS is a rare lesion, surgical series are relatively small and span lengthy time periods. Consequently, risk factors that influence early and late outcomes are not well defined. Patients who come to surgery during infancy are particularly challenging, but little attention has been directed as to whether or not young age influences outcomes. This review suggests that complicating associated features of elastin arteriopathy are more prevalent in patients who require relief of SVAS during infancy, and that concomitant lesions significantly increase the difficulty and risk of treating younger patients with SVAS.

Surgical management of supravalvular aortic stenosis: does Brom three-patch technique provide superior results?

BACKGROUND

Various surgical techniques have been proposed to repair supravalvular aortic stenosis. However, the optimal approach remains to be determined. The present study was undertaken to evaluate the results of surgery for supravalvular aortic stenosis and to compare the symmetric three-patch repair (Brom technique) with other surgical reconstructions.

METHODS

Between 1995 and 2007, 34 patients with supravalvular aortic stenosis underwent surgery. Fourteen patients (41%) had Williams syndrome. Supravalvular stenosis was discrete in 24 patients (71%) and diffuse in 10 (29%). Eight patients (23%) underwent one-patch repair; 3 patients (9%) had inverted bifurcated patch enlargement (Doty repair) and 23 patients (68%) had symmetric repair (Brom three-patch technique). Follow-up was complete and ranged from 6 months to 12 years (mean, 5.8 years).

RESULTS

There was one early and no late deaths. One patient (with one-patch repair) underwent reoperation for residual obstruction. At last follow-up, left ventricle to aorta peak gradient was 45 +/- 28 mm Hg after one-patch repair, 30 +/- 9 mm Hg after Doty operation, and 11 +/- 18 mm Hg after symmetric Brom procedure. Brom repair was associated with a low incidence of residual obstruction (peak gradient > or = 40 mm Hg) (2 of 22; 9.1%) and moderate aortic insufficiency (1 of 22; 4.5%).

CONCLUSIONS

Brom three-patch repair provides symmetric reconstruction of the aortic root in patients with supravalvular aortic stenosis. This may lead to improved midterm results in terms of relief of the obstruction and incidence of aortic insufficiency.

Mechanisms and treatment of cardiovascular disease in Williams-Beuren syndrome

Williams-Beuren syndrome (WBS) is a microdeletion disorder caused by heterozygous loss of approximately 1.5-Mb pairs of DNA from chromosome 7. Patients with WBS have a characteristic constellation of medical and cognitive findings, with a hallmark feature of generalized arteriopathy presenting as stenoses of elastic arteries and hypertension. Human and mouse studies establish that defects in the elastin gene, leading to elastin haploinsufficiency, underlie the arteriopathy. In this review we describe potential links between elastin expression and arteriopathy, possible explanations for disease variability, and current treatment options and their limitations, and we propose several new directions for the development of nonsurgical preventative therapies based on insights from elastin biology.

Surgery for supravalvular aortic stenosis - the three-patch technique

The objective of this paper is to describe the three-patch technique for repair of supravalvular aortic stenosis (SVAS). Supravalvular aortic stenosis is a rare malformation as a result of an abnormal thickening of the aortic wall. SVAS may present in two forms: a localized form (affecting only the aortic sinotubular junction) and a diffuse form, where the aortic arch and its side branches are also affected. Since 1960, multiple surgical techniques have been described with the aim of relieving the aortic narrowing and restoring the aortic root. We present the three-patch technique as originally developed by Brom. After transection of the aorta at the sinotubular junction, three longitudinal incisions are made into the three sinuses. The aortic root geometry is then restored by placement of three separate patches of autologous pericardium in the opened sinuses. Brom's technique provides a complete and symmetric restoration of the aortic anatomy. The technique is illustrated by angiographies, surgical drawings, videos and a review of the literature. The results of the three-patch technique are good and our long-term experience will be described.

The surgical anatomy of the aortic root

There is still no consensus on the best way to describe the anatomy of the aortic root. Different surgeons use the term 'annulus' to describe different parts of the components of the aortic valve. There is also lack of agreement within the surgical literature with regard to the nature of the ventriculo-aortic junction. In this review, I describe the components of the aortic valve, and its supporting ventricular structures, as seen by the anatomist. The essence of the valvar complex is the semilunar attachments of the valvar leaflets. These extend from their basal attachments within the left ventricle to their distal attachments at the sinutubular junction. The extent of the leaflets defines the length of the root. Within this length, the semilunar lines of attachments of the leaflets cross the anatomic ventriculo-aortic junction, the latter being the circular line marking the transition from ventricular to arterial walls. The posterior part of this line is made up of fibrous continuity between the leaflets of the aortic and mitral valves. Because the semilunar lines of attachment cross this anatomic junction, crescents of ventricular wall are incorporated at the base of each arterial valvar sinus, whilst triangles of arterial wall are incorporated between the zones of apposition of the valvar leaflets as they extend to become attached at the sinutubular junction. The overall, three-dimensional arrangement of the leaflets takes the form of a crown. It is questionable whether this crown is best described as an 'annulus', just as it is questionable whether the leaflets should be described as 'cusps', or only the peripheral parts of the zones of apposition between the leaflets as the 'commissures'. Only time, and usage, will answer these questions.