P184 - DIRECT TRANS-ATRIAL IMPLANTATION OF SAPIEN 3 VALVE FOR MITRAL ANNULAR CALCIFICATION: MULTI CENTER EXPERIENCE

Background: Mitral valve replacement in the presence of severe annular calcification is associated with high morbidity and mortality. As an alternative strategy for addressing severe MAC in patients with high surgical risk, a transcatheter heart valve (THV) can be implanted surgically into the annulus via a trans-atrial approach. This study reports the short and intermediate clinical outcomes of MVR via a direct surgical approach using the SAPIEN3 THV in patients with severe circumferential MAC at two Canadian centers.

METHODS AND RESULTS:

Methods:
This retrospective study was conducted at St Michael’s Hospital (Toronto) and Foothills Hospital (Calgary). Charts were reviewed between 1/1/2018 and 30/4/2022 to identify patients with severe circumferential MAC who had undergone direct surgical implantation of a SAPIEN3-THV. Pre-operative CT imaging was used to guide sizing. The anterior leaflet was removed, the THV was placed atrially to avoid LV-outflow tract (LVOT) obstruction, and additional sutures were used to secure the prosthesis along with balloon over-inflation as necessary to prevent paravalvular leak (PVL). Primary outcomes were 30-day mortality and debilitating stroke. Secondary outcomes included LVOT obstruction/gradient, degree of PVL, and transvalvular mean pressure gradient, blood product transfusions, emergent reoperation, and length of stay.

Results:
Nine patients at the two centres underwent MVR using a SAPIEN3-THV. All were female with mean age 66.67±9.03 years. Seven patients presented with severe MS, 1 had severe MR, and 1 had mixed mitral valve disease. All were considered high-risk or inoperable for conventional surgical MVR. SAPIEN3-THV was successfully implanted in all patients. There were no deaths at 30-days, but 1 patient had a neurological event. Sternotomy was performed in 7 patients and a right mini-thoracotomy approach was used for 2 patients. Four patients received a 26mm SAPIEN3 and 5 patients received a 29mm SAPIEN3-THV. There were no cases of LVOT-obstruction. Mean CPB and aortic cross-clamp times were 107.44±36.12 and 72.38±25.95 minutes, respectively. One patient had more than trace PVL (mild). The mean transvalvular pressure gradient was 4.44±1.95 mmHg. Two patients required emergent reoperation due to bleeding. Median length of ICU and hospital stays were 3 (IQR:1.5-21.5) and 16 (IQR:13.5-34) days, respectively.


Conclusion: This case series suggests that direct surgical implantation of SAPIEN3-THV in high surgical risk or inoperable patients with severe MAC is technically feasible and associated with reasonable short-term outcomes using both sternotomy and minimally invasive approaches. Larger studies with longer follow-up and continued technical advancements can better delineate the role of this surgical strategy.