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............................................................... aortic dilation may be induced and progress during and after pregnancy; there is a risk of dissection (see section 3.5.7). • IE prophylaxis: recommended only for high-risk patients (see section 3.4.6).

4.5.2 Supravalvular aortic stenosis 4.5.2.1 Introduction and background Supravalvular AS (SupraAS) may occur as a characteristic feature of WilliamsBeuren syndrome or be isolated/familial, which are respectively caused by deletion of the elastin gene located on chromosome 7q11.23 or a mutation in this same gene. These genetic defects lead to obstructive arteriopathy of varying severity, which is most pronounced at the sinotubular junction.177 SupraAS may also be encountered in the setting of familial homozygous hypercholesterolaemia.178 SupraAS occurs as a localized fibrous diaphragm just distal to the coronary ostia or, most commonly, as an external hourglass deformity with a corresponding luminal narrowing of the aorta, or as diffuse stenosis of the ascending aorta. It may be associated with aortic valve abnormalities, hypoplasia of the entire aorta, involvement of coronary ostia, or stenosis of major branches of the aorta or PAs. 4.5.2.2 Clinical presentation and natural history The majority of patients present in childhood with symptoms of either outflow obstruction or myocardial ischaemia. While progression of SupraAS is rare in adulthood, adults remain at risk for cardiac complications.179 Sudden death occurs rarely, but it is more common in SupraAS with WilliamsBeuren syndrome, with diffuse peripheral PA stenosis, or with CAD, particularly related to anaesthetic procedures.

4.5.2.3 Diagnostic work-up See section 3.3 for general principles. Auscultation typically reveals a loud systolic ejection murmur best heard at the left lower sternal border without associated ejection click or diastolic murmur of AR. • Echocardiography enables the anatomic diagnosis of SupraAS when the acoustic window allows. Doppler echocardiography provides pressure gradients, but these may over- or underestimate the actual pressure drop across the obstruction. TOE allows good visualization of the coronary ostia and 3D TOE can be used for detailed evaluation of the stenotic region.180 • For exercise testing, see valvular AS (section 4.5.1). ©ESC 2020

Figure 5 Management of severe left ventricular outflow tract obstruction. AS = aortic stenosis; LVEF = left ventricular ejection fraction; LVOTO = left ventricular outflow tract obstruction; PAP = pulmonary artery pressure; PH = pulmonary hypertension; SubAS = subaortic stenosis SupraAS = supravalvular aortic stenosis. aSee Section 4.5. There are fundamental differences in management decisions compared to valvular AS, particularly because a valve substitute with its consequences is generally not required. bPeak velocity >5.5m/s; severe calcification þ peak velocity progression >_0.3 m/s/y; markedly elevated neurohormones (>3-fold age- and sex-corrected normal range); severe PH (systolic PAP >60 mmHg without other explanation). Downloaded from academic.oup.com/eurheartj/article/42/6/563/5898606 by guest on 07 October 2026