We have read with great interest the article by Sung et al. [1] titled ‘Is tricuspid valve replacement (TVR) a catastrophic operation?’ They showed only 1.3% in-hospital mortality among 80 cases of TVR and suggested reasonable explanations for this favourable result: younger age, better myocardial protection, larger prostheses and modified ultrafiltration. Firstly, we would like to emphasise that TVR itself is not a risky or complicated operation that increases early mortality compared with tricuspid valve (TV) repair [2]. Until now, in the majority of rheumatic tricuspid regurgitation (TR) cases, TVR was performed after left valvular surgery or as a treatment for late TR. Late TR might be caused by left-heart disease, right ventricle (RV) dilatation and dysfunction, persistent pulmonary hypertension, chronic atrial fibrillation or by organic TV disease. The outcome of isolated TVR is poor, because right ventricular (RV) dysfunction has already occurred at the time of TVR. Mangoni et al. [3] showed outcomes following isolated TVR with in-hospital mortality of 20% in this article; 87% of patients had isolated TVR following a previous left-valve operation. Compared with this, we would like to ask the authors, ‘How many patients had isolated TVR after (non-concomitant) left heart valve surgery?’ We speculate that in this study, isolated TVR (n = 24) was almost always from endocarditis or congenital disease; nearly zero patients had isolated TVR due to left rheumatic valvular surgery. Moreover, compared with previous papers, the ratio of re-operation is low (50%) and the ratio of initial TVR as a concomitant operation is high (29% among the 56 concomitant operations). This suggests that it is not the operative technique (as they mentioned above) but the early TVR that might have improved the surgical outcomes. We would like to emphasise that due to