Type F Quadricuspid Aortic Valve at Three-Dimensional Transoesophageal Echocardiography

Figure 1. Transoesophageal examination was performed using a X8-2t (Philips, Amsterdam, The Netherlands) probe. Midesophageal aortic valve short-axis view (35° angle) demonstrated four cusps, with two equal-sized larger cusps and two unequal-sized smaller cusps, which means Hurwitz & Roberts type F quadricuspid valve (QAV) (A) [1,2]. Midesophageal aortic valve short-axis view in mid-systole showed the four commissures (B). Color Doppler midesophageal long-axis view demonstrated central moderate aortic regurgitation (vena contracta width = 4 mm, no holodiastolic flow reversal in proximal descending aorta) (C). Midesophageal long-axis view (135° angle) highlighted the characteristic leaflet coaptation pattern of QAV, with a coaptation length of 6 mm measured in end-diastole (D). Three-dimensional high resolution four-beats (61 Hz) standard reconstruction (E) and three-dimensional TrueVue (Philips, NL) rendering (F) provided a detailed visualization of cusps configuration supporting the diagnosis of QAV and its classification (Video S1). QAV is a rare congenital abnormality with a prevalence of less than 0.05% in the general population [3,4]. Hurwitz and Roberts QAV classification is the most widely adopted one, and it identifies seven morphologic variants, from type A to type G [1,2]. This condition is frequently associated with progressive valve dysfunction, primarily due to isolated aortic regurgitation, while significant aortic stenosis is quite rare. The cumulative incidence of aortic valve intervention in QAV is comparable to that observed in bicuspid aortic valve. However, cumulative incidence of aortic surgery in patients with QAV is lower compared to those with bicuspid aortic valve, although it is higher than in the general population [2,5]. Aortic valve replacement with either a mechanical or a biological prosthesis can be performed. However, aortic valve repair should be considered as a first-line option, particularly in young patients with suitable anatomy, even though long-term durability data in this setting remain limited; tricuspidization of a QAV may be an option, particularly in cases with two larger and two smaller leaflets (Hurwitz and Roberts types F and G), or in the case of three larger and one smaller leaflets (Hurwitz and Roberts types B). In the literature, two cases of type F QAV associated with severe aortic regurgitation have been reported, without other significant valvular or aortic lesions. Both patients underwent aortic valve replacement [6,7]. If aortic dilatation is detected, Bentall or Ross procedures should be considered [8,9]. Anatomical studies of normal tricuspid aortic valves reported a mean coaptation length of 3.8 ± 0.8 mm [10]; however, corresponding data on QAVs are currently lacking. QAVs may show a greater coaptation length, potentially related to valve morphology, and future studies on this topic are needed.