•The patient presented to clinic with a degenerated bioprosthetic MV, with severe stenosis and insufficiency, in addition to a hypertrophied IAS.

•Due to her comorbidities and history of open sternotomy, the surgical team deemed her as a candidate for percutaneous trans-septal valve-in-valve TMVR.

•The procedure was performed in a hybrid operating room, where the heart team used common femoral vein access to puncture the IAS. This technique aids in delivery of the SAPIEN 3 transcatheter heart valve system (Edwards LifeSciences Corp., Irvine, CA, USA).

•However, the thickness of the IAS made attempts at delivering the replacement MV through the IAS unsuccessful. Traditional technique requires insertion of a 14 Fr delivery sheath and septostomy with a 16 mm balloon.

•Alternatively, the heart team dilated the IAS with a larger 22 mm balloon catheter and used a 65 cm extended valve delivery system to deliver the replacement valve.

•The patient tolerated the TMVR well, in which a post-operative transesophageal echocardiography showed a well-seated valve with no evidence of paravalvular leak, MV stenosis, or MV insufficiency. She was discharged in stable condition on a beta blocker.

•One month later, an echo showed minimal mitral valve insufficiency, with no evidence of paravalvular leak or MV stenosis.

•Performing trans-septal valve-in-valve TMVR via dilating the IAS with a larger balloon catheter and using an extended valve delivery system is safe in severely, comorbid patients with complicated septal anatomy.

•