Tehran University of Medical Sciences The Research in Heart Yield and Translational Medicine (RHYTHM) 3115-7270 17 3 2022 07 28 112 118 Mohammad Sahebjam Tehran Heart Center, Tehran University of Medical Sciences, Tehran, Iran. Alimohammad Haji Zeinali Tehran Heart Center, Tehran University of Medical Sciences, Tehran, Iran. Kyomars Abbasi Tehran Heart Center, Tehran University of Medical Sciences, Tehran, Iran. Solmaz Borjian Tehran Heart Center, Tehran University of Medical Sciences, Tehran, Iran. 2022 03 12 2022 07 21 Background: Transcatheter tricuspid valve-in-valve (TTViV) replacement has become an alternative treatment in high-risk patients with bioprosthetic valve degeneration. This is the first report on the mid to long-term echocardiographic findings of patients who underwent TTViV replacement in a cardiac referral center in Iran.   Methods: Data of 12 patients, consisting of 11 women and 1 man, who underwent TTViV replacement between 2015 and 2021 were reviewed retrospectively. The patients underwent echocardiography before the procedure and at a mean follow-up time of 3.17±1.75 years. Results: All the patients had New York Heart Association (NYHA) function class III/IV before TTViV. Six patients had tricuspid regurgitation, 1 had tricuspid stenosis, and 5 had both. All the patients had successful TTViV. The mean time from the initial valve surgery to TTViV was 6.25±2.45 years. At follow-up, 2 patients had died: 1 due to COVID-19 pneumonia and 1 without a known cause. The remaining 10 patients experienced improvements in the NYHA functional class. Echocardiographic measures showed significant improvements. Transvalvular mean gradient pressure decreased from 7.08±1.98 mm Hg to 5.29±1.63 mm Hg (P=0.028), tricuspid valve pressure half time decreased from 245.00±49.46 ms to 158.64±57.41 ms (P=0.011), tricuspid regurgitation gradient decreased from 39.91±7.31 mm Hg to 26.72±8.99 mm Hg, and left ventricular ejection fraction increased from 47.71±4.70% to 49.79±4.58% (P=0.046). There was no significant paravalvular or transvalvular leakage at follow-up. Conclusion: This is a single-center report on the mid and long-term echocardiographic follow-up of patients after TTViV replacement.  Our study showed that TTViV was a safe and efficient method in treating high-risk patients with degenerated bioprosthetic tricuspid valves and had favorable echocardiographic and clinical results. https://rhythm.tums.ac.ir/index.php/jthc/article/view/1632 https://rhythm.tums.ac.ir/index.php/jthc/article/download/1632/1015