Letter to the Editor on “Mid‐Term Clinical Outcomes and Predictors of Mortality and Major Adverse Cardiovascular Events Following Cardiac Valve Replacement Surgery: A Retrospective Cohort Study From a Tertiary Center in Iran”

We read with great interest the article by Saffar et al. [1], titled “Mid-term Clinical Outcomes and Predictors of Mortality and Major Adverse Cardiovascular Events Following Cardiac Valve Replacement Surgery.” The study provides very useful real-world data from a large surgical cohort; however, several methodological issues merit consideration to enhance the interpretation of their findings. First, single-center retrospective design limits generalizability and increases vulnerability to selection biases, especially given potential shifts in patient populations, surgical techniques, and perioperative care over time. Recent guidelines suggest that a clear “target trial” structure should be predefined to enhance transparency in eligibility criteria, study timing, and follow-up methodology—which seems to be lacking in the present study [2]. Second, competing-risk analysis was also not done, notwithstanding the remarkable contribution of non-cardiac deaths and valve-related complications during follow-up in this cohort. At mid-term follow-up after valve surgery, there is a considerable probability of non-cardiac mortality. If the competing risks are not taken into account, the overall cumulative incidence might be exaggerated [3]. Indeed, other similar studies [3] utilized competing-risk regression to avoid inflated estimates of events. Finally, while the authors identify predictors of adverse outcomes, interpretation should remain prognostic rather than causal. Recent developments in cardiovascular prognostic modeling, including machine learning, show great promise but also highlight the imperative for careful internal and external validation before clinical use [4, 5]. Such methods provide a basis for further discussion to strengthen these findings and their implications. In conclusion, the study by Saffar et al. provides important interim data related to valve replacement outcomes, but addressing the above-stated methodological concerns, such as the addition of more transparent design frameworks, correct consideration of competing risk, and better-performing prognostic strategies, would not only increase analytical accuracy but also clinical utility for the conduct of future work in this important field. The authors have nothing to report. The authors have nothing to report. The authors have nothing to report. The authors declare no conflicts of interest. The authors have nothing to report.