Transcatheter mitral valve-in-valve procedures: an ongoing successful journey with unproven long-term benefit

Mitral valvular heart disease increases sharply with age as a consequence of the predominance of degenerative valvular diseases, as well as being secondary to an increase in congestive heart failure. Nevertheless, owing to the rise in patients’ life expectancy, redo valve surgery is increasingly necessary and owing to technical aspects [1] or poor clinical conditions [2], it is associated with increased operative mortalities. Extensive coverage by neoendocardium or calcif ication is frequently present, making reoperation sometimes extremely diff icult. Sometimes irreparable damage, one of the greatest nightmares of a cardiac surgeon, may also occur [1]. Moreover, the remaining annulus, after decalcification and valvectomy, can be become very weak and paravalvular leaks do frequently ensue [3]. Thus, the avoidance of the removal of the malfunctioning bioprosthesis significantly decreases the surgical burden in these patients. Interestingly, excising only the leaflets of the damaged bioprosthesis and, thus, leaving the old ring in situ has already been proposed by surgeons approximately 20 years ago [1,4]. Given the frequency of comorbidities and the high risk of surgery in these elderly patients, a sharp rise in catheter-based techniques has emerged over the past 5 years.