Transcatheter mitral valve-in-ring implantation with LVOT obstruction after failed LAMPOON – Limitations of the transcatheter valve-in-ring procedure

A 70-year old man, with history of surgical mitral valve repair in 2007 and 2008 (Carpentier-Edwards Physio Ring 28mm, Edwards Lifesciences) was admitted because of exertional dyspnea (New York Heart Association class III). Initial echocardiography showed severe eccentric transvalvular mitral regurgitation with an elongated anterior mitral leaflet (AML) (Figure 1A). Because of increased estimated surgical risk, the interdisciplinary heart team opted for a transcatheter valve-in-ring implantation with concomitant laceration of the anterior mitral leaflet to prevent outflow obstruction (LAMPOON). The AML was lacerated using transcatheter electrosurgery with following implantation of an Edwards SAPIEN 3 Ultra 26mm valve (Edwards Lifesciences) (Figure 1B and C). Despite the LAMPOON procedure, dynamic left ventricular outflow tract obstruction (LVOTO) due to systolic anterior movement (SAM) of the lacerated AML was noted (LVOT mean gradient 53 mmHg in transesophageal echocardiography), presumably because the AML was not sufficiently lacerated from the base of the leaflet. Alcohol septal ablation (ASA) was successfully accomplished during the same procedure with following resolution of the LVOTO (Figure 1C). Because of suspected paravalvular regurgitation, post-dilatation of the transcatheter heart valve (THV) was performed. However, postprocedural echocardiography revealed residual para-annular leakage resulting in mild to moderate regurgitation, which was accepted, and the patient was discharged. Seven days later, the patient presented with progressive dyspnea. Transesophageal echocardiography confirmed relevant anterolateral and –septal para-annular leakage (Figure 1D). Interventional leak closure was discussed but ultimately refrained from. Patient-provider discussion resulted in re-operation. The para-annular leaks and the lacerated AML were inspected intraoperatively (Figure 1E and F) revealing the cause for the para-annular leaks: the mitral ring had been presumably ruptured after THV post-dilation. Mitral valve replacement with an Epic™ 31mm prosthesis (Abbott) was performed. The patient recovered well and was discharged to cardiac rehabilitation. Transcatheter mitral valve replacement (TMVR) is an established therapeutic option for patients with high or prohibitive surgical risk. Iatrogenic LVOTO after TMVR is a potentially life-threatening complication. Meticulous pre-procedural planning may help to assess possible predictors and predict the risk of LVOTO. With preemptive ASA and the LAMPOON procedure there are two interventional methods to mitigate the risk of LVOTO. However, this case demonstrates the limitations of an interventional treatment in an anatomically challenging situation.