Novel mitral valve technologies-transcatheter mitral valve implantation: a systematic review

Background: Valvular heart disease is an important cause of morbidity and mortality throughout the world; in industrialized nations, mitral regurgitation (MR) is the most common valvular lesion. Untreated, severe MR has a poor prognosis, with a 5-year mortality rate of up to 50%. Surgical repair of symptomatic, severe primary MR has been demonstrated to improve survival. The aim of this review is to assess the early outcomes of newly developed transcatheter mitral valve implantation technologies for the treatment of secondary native valve disease. Furthermore, the outcomes of patients receiving transcatheter treatment of regurgitant failure of surgically repaired or replaced mitral valve has also been addressed. Methods: A systematic review of twenty-five studies assessing the outcomes of patients undergoing transcatheter mitral valve implantation for native mitral regurgitation or failed prior surgical repair or bioprosthetic replacement was carried out. Results: The outcomes of 112 patients undergoing transcatheter mitral valve replacement for secondary mitral regurgitation using six different valve systems were assessed. There were 15 early deaths and 24 deaths over the follow-up period. The outcomes of 44 patients undergoing transcatheter valve-in-valve replacement were assessed with an overall mortality of ten patients. There were 20 patients included who had valve-in-ring transcatheter mitral replacement for previous failed repair. The total mortality was five patients during the follow-up period. Conclusions: Transcatheter mitral valve implantation represents a new evolution in management of valvular disease and affords management options to patients who historically may not have been offered treatment. Early results have demonstrated some promise and improvements in technology, imaging modalities and patient selection will surely result in a reliable and durable valve.