Discussion

Supravalvular aortic stenosis is a progressive arteriopathy, which is commonly associated with Williams–Beuren syndrome ^{Reference Fricke, d’Udekem and Brizard1–Reference Mongé, Eltayeb and Costello3} and affects the great arteries and mostly the supravalvular segment of the aorta, The pathological appearance of the stenotic aortic wall can be discrete or diffuse at the sinotubular junction level, which indicates the degree of the elastin gene defect. The diffuse type of stenosis and Williams–Beuren syndrome lie at the severe side of the spectrum with associated multifocal vascular lesions. ^{Reference Mitchell and Goldberg4} Thus, the diffuse type of aortic pathology has been found to be a risk factor for re-operation ^{Reference Mitchell and Goldberg4–Reference Liu, Gao and Sun7} and reported as a risk factor for mortality. ^{Reference Deo, Burkhart and Dearani8,Reference Deo, Burkhart and Schaff9} In our cohort, two out of three of the patients who were re-operated on and the one patient who died had a diffuse structure. Hence, one of the factors that caused death and reintervention in our cohort could be diffuse structural type.

Pulmonary arterial stenosis is stated to be a risk factor for re-operation, which reflects the severity of the disease. ^{Reference Padalino, Frigo and Comisso5,Reference Imamura, Prodhan and Dossey6} Pulmonary stenosis accompanied by supravalvular aortic stenosis leads to biventricular pressure overload and cardiac complications of stenotic outflow valves. ^{Reference Mitchell and Goldberg4} The intervention rate for concomitant pulmonary stenosis at initial repair has been reported as 41 over 125 patients(32%) in a multi-center study, ^{Reference Padalino, Frigo and Comisso5} which compares with approximately 16% of the patients in our cohort with pulmonary stenosis at the initial repair who had an intervention. In addition, only one re-operated patient had concomitant pulmonary stenosis at the initial procedure. We can attribute this difference to a lower incidence of Williams–Beuren syndrome in our cohort.

Diffuse structural disease of the aorta and the branch pulmonary arteries are the main characteristics of the cardiovascular anomalies of Williams–Beuren syndrome. Despite the severe nature of this disease, surgical treatment with excellent outcomes can be achieved. ^{Reference Fricke, d’Udekem and Brizard1,Reference Cha, Song and Lee2} One-third of our cohort had Williams–Beuren syndrome; however, only one patient who was re-operated on had this syndrome. Aggressive progression of the disease results in the early onset of clinical symptoms and reflects the severity of the pathology. However, this syndrome has not been defined as a risk factor for adverse cardiac events. Conversely, the diffuse structural pathology and pulmonary lesions that are also associated with Williams–Beuren syndrome have been stated as risk factors. ^{Reference Padalino, Frigo and Comisso5,Reference Deo, Burkhart and Schaff9}

Surgical treatment with different techniques has been advocated with remarkable outcomes. ^{Reference Fricke, d’Udekem and Brizard1,Reference Mongé, Eltayeb and Costello3,Reference Padalino, Frigo and Comisso5,Reference Liu, Gao and Sun7,Reference Wu, Mondal and del Nido10} There are several methods described other than the McGoon and Doty procedures, such as the Brom three-patch technique, the Myers interdigitating technique, and a two separate patches technique; however, there is no consensus about a superior technique. ^{Reference Deo, Burkhart and Dearani8,Reference Bakhtiary, Amer and Etz11,Reference Roemers, Kluin and de Heer12} According to a multi-center study, the single- and pantaloon-patch methods were the most preferred two surgical techniques among surgeons with both 110 patients (36.7%); however, no superiority was noted. ^{Reference Padalino, Frigo and Comisso5} Both techniques have been found to be simple, reproducible and have excellent outcomes, and the authors pointed out that patient-specific procedures provide better results in their experience. ^{Reference Deo, Burkhart and Dearani8} Conversely, other reports have indicated that the Doty procedure was superior to the single-patch technique in relation to freedom from re-operation. ^{Reference Ibarra, Spigel and John13,Reference Kaushal, Backer and Patel14} Regarding our data, we can speculate that the Doty procedure was superior, considering the re-operation rates. However, the freedom from re-operation estimates showed no significant difference. This result can be attributed to the good outcomes of the McGoon single-patch repair until the fifth year of follow-up. Ibarra et al stated that estimates of freedom from re-operation were 67% at the 10th year after the initial operation, which compared to 44.4% in our cohort.

Surgical treatment of supravalvular aortic stenosis has been performed with good survival outcomes, ^{Reference Padalino, Frigo and Comisso5,Reference Imamura, Prodhan and Dossey6,Reference Deo, Burkhart and Schaff9,Reference Wu, Mondal and del Nido10,Reference Roemers, Kluin and de Heer12} and no significant difference between operational techniques has been found in terms of survival. ^{Reference Roemers, Kluin and de Heer12,Reference Kramer, Absi and Hetzer15} The single early death in our cohort had the Doty procedure; however, this result cannot only be attributed to the surgical method considering the patient’s risk factors. Early infancy at initial repair, a higher residual gradient, pre-existing aortic stenosis, and diffuse type lesions have been reported to be risk factors for survival. ^{Reference Padalino, Frigo and Comisso5,Reference Deo, Burkhart and Dearani8} Roemers et al ^{Reference Roemers, Kluin and de Heer12} reported in their 52-year experience that in the long-term follow-up, survival of the operated patients was remarkably low compared with the general population, and thus close follow-up is recommended.

Coronary artery ostial narrowing is one of the aetiologic factors that associated with myocardial ischaemia which can lead to probable early and late mortality for supravalvular aortic stenosis. ^{Reference Padalino, Frigo and Comisso5} The incidence of this concomitant anomaly ranges between 1 and 26% of cohorts. ^{Reference Imamura, Prodhan and Dossey6,Reference Deo, Burkhart and Dearani8–Reference Wu, Mondal and del Nido10} It was reported that concomitant surgical intervention of coronaries were required for 26% of patients with ostial coronary stenosis in a series ^{Reference Wu, Mondal and del Nido10} ; contrarily, there are reports that none of the patients had concomitant coronary intervention in their cohorts. ^{Reference Liu, Gao and Sun7,Reference Deo, Burkhart and Schaff9} Most of the lesions were treated with resection of excessive tissues around the ostium of coronaries. ^{Reference Wu, Mondal and del Nido10} Conversely, patch augmentation of the coronaries can be performed for other ostial anomalies. ^{Reference Padalino, Frigo and Comisso5,Reference Deo, Burkhart and Dearani8} In our cohort, there were two patients underwent a concomitant coronary intervention. One patient with right coronary ostial stenosis had patch augmentation by extending one leg of the patch to coronary with the Doty technique and the other patient was in McGoon group and had patch augmentation of left main coronary stenosis with a different separate patch. It was advocated that three-patch repair had a better relief on coronary arteries considering the ease of placement of the patches. ^{Reference Mongé, Eltayeb and Costello3}

The single-patch and the Doty techniques are commonly performed, but there has been a tendency to change the operational strategy to symmetrical reconstructions such as the Brom method, despite longer cross-clamp times and related problems. ^{Reference Fricke, d’Udekem and Brizard1,Reference Mongé, Eltayeb and Costello3,Reference Imamura, Prodhan and Dossey6,Reference Kaushal, Backer and Patel14,Reference Kramer, Absi and Hetzer15} Although there are no data on the long-term outcomes of these symmetrical reconstruction methods, recent studies have indicated promising results. ^{Reference Fricke, d’Udekem and Brizard1,Reference Kramer, Absi and Hetzer15} Considering the disadvantages of those procedures, we have no intention to change our strategy to symmetric repair. Symmetrical aortic sinus repairs have been found to result in a lower post-operative gradient, which is associated with lower re-operation rates. ^{Reference Mongé, Eltayeb and Costello3,Reference Kaushal, Backer and Patel14} However, three-sinus repair techniques have not been found to be statistically superior in terms of time-related analysis. ^{Reference Kramer, Absi and Hetzer15} A post-procedural aortic residual gradient has been stated as a predictor of mortality. ^{Reference Deo, Burkhart and Dearani8,Reference Deo, Burkhart and Schaff9} Although a residual gradient was not defined as a risk factor for re-operation in recent studies, in our cohort all the patients who underwent re-operation had a post-operative peak gradient above 40 mmHg. Kaushal et al ^{Reference Kaushal, Backer and Patel14} stated that their choice of technique evolved from the single-patch to the Brom method due to higher residual pressure gradients and a higher rate of re-operations. Likewise, a similar transformation occurred gradually from the McGoon to the Doty technique in our clinic.