We would like to congratulate the authors on their first successful reconstructive operation performed in a patient with congenital absence of one of tricuspid valve's cusps [1]. Along with the cases of complete absence of the anterior or posterior cusp of the right atrioventricular (AV) valve presented in the article, the spectrum of this pathology can include the absence of a major part (2/3) of the anterior cusp [2] or the absence of all cusps of the right AV valve (unguarded tricuspid orifice) [3]. We would like to share our own surgical experience and comment on some problems related to this rare pathology. In 2007 and in 2011, two patients with severe insufficiency of the right AV valve and atrial fibrillation were successfully operated on at Bakoulev Center for Cardiovascular Surgery. The first patient, a 32-year-old man, had a completely absent anterior cusp and its subvalvular apparatus as well as dysplasia of the septal and posterior cusps. The diameter of the valve annulus was 57 mm (Z score = +6.8). The second patient, a 42-year-old man, had a completely absent posterior cusp and the anterior cusp was hypoplastic with shortened chordae. The diameter of the valve annulus was 63 mm (Z score = +8.6). Both patients underwent biological valve (BioLAB 33, Moscow, Russia) replacement. Two variants of the clinical course of congenital tricuspid insufficiency due to valvular dysplasia have been described [2]. In the first and less favourable variant, the neonates and infants develop marked right heart failure with cyanosis and cardiomegaly, leading to the death within the first weeks and months of life. In the second, more favorable variant, the decompensation of cardiac function due to severe tricuspid insufficiency, develops in adulthood and manifests as right ventricular failure and heart arrhythmia. This variant of the natural course has been noted in all 7 reported cases to date (including two of our cases) with an absent cusp of the right AV valve [1,2, unpublished data]. The choice of the method of correction (reconstruction or replacement) in this pathology is determined by the following anatomical features: the size of the absent cusp, the degree of valve annulus dilatation, anatomical development and functional capacities of the remaining cusps and their subvalvular apparatus. Based on the above criteria, the feasibility of reconstructive surgery in this pathology is low, and for this reason, valve replacement has been performed in the majority of patients (6 of 7).