Mitral Valve Lithotripsy Using the SMARTWAVE Balloon for Severe Mitral Annular or Valvular Calcification (SMART-MAC): First in Human Study

Mitral stenosis (MS) is a heavily symptomatic valvular heart disease. Common causes of MS included chronic rheumatic heart disease (CRHD) and mitral annular calcification (MAC). Current guideline recommends percutaneous balloon mitral valvuloplasty (PBMV) being the first line intervention for rheumatic MS with favorable anatomy. However, severely calcified mitral valve (i.e. those with Wilkins scores>8) makes the mitral valve non-pliable and carries high risk of severe mitral regurgitation (MR) (4-19%) with conventional balloon valvuloplasty. MAC is an increasingly recognized disease associated with atherosclerotic risk factors, and a well-recognized valve morphology that responses poorly with PBMV. Besides, conventional open-heart surgery for MAC-associated mitral valve dysfunction carries high mortality. Transcatheter mitral valve replacement with valve-in-MAC has become an alternative in treating these patients. However, valve-in-MAC is not always feasible and still carries operative and 30-day mortality.

Intravascular lithotripsy is an approved adjunct interventional therapy in treating calcified lesions to facilitate stenotic lesion opening in peripheral vascular disease and coronary artery disease. The off-label use of current peripheral lithotripsy balloon in mitral valve as a compassionate treatment or as an adjunct treatment before mitral balloon valvuloplasty and transcatheter mitral valve replacement has been reported with success . A possible mechanism is that lithotripsy preferentially impacts hard tissue, disrupts calcium, and leaves soft tissue undisturbed, improving valve pliability, preventing leaflet damage, and making subsequent valvuloplasty safer. However, the off-label use of multiple peripheral lithotripsy balloons in mitral valve is technically complicated.

SmartWave balloon was specifically designed lithotripsy balloon for calcified aortic stenosis. This first-in-human study aims to apply the SmartWave lithotripsy balloon in treating calcified mitral stenosis due to MAC or severely calcified rheumatic mitral valve.