Iatrogenic Atrial Septal Defect Requiring Transcatheter Closure Following Transcatheter Mitral Valve Repair

BACKGROUND: Transcatheter mitral valve repair with the MitraClip system has been established in selected high-risk patients. The MitraClip procedure results in a relatively large iatrogenic atrial septal defect (iASD). This study aimed to investigate the prevalence and clinical course of iASD requiring transcatheter closure following the MitraClip procedure.Methods and Results: This study was conducted at all 59 institutions that perform transcatheter mitral valve repair with the MitraClip system in Japan. The data of patients on whom transcatheter iASD closure was performed were collected. Of the 2,722 patients who underwent the MitraClip procedure, 30 (1%) required transcatheter iASD closure. The maximum iASD size was 9±4 mm (range, 3-18 mm). The common clinical course of transcatheter iASD closure was hypoxemia with right-to-left shunt or right-sided heart failure with left-to-right shunt. Of the 30 patients, 22 (73%) required transcatheter closure within 24 h following the MitraClip procedure, including 12 with hypoxemia and 5 with right-sided heart failure complicated with cardiogenic shock. Of the 5 patients, 2 required mechanical circulatory support devices. Twenty-one patients immediately underwent transcatheter iASD closure, and hemodynamic deteriorations were resolved; however, 1 patient died without having undergone transcatheter closure. CONCLUSIONS: Transcatheter iASD closure was required in 1% of patients who underwent the MitraClip procedure. Many of these patients immediately underwent transcatheter iASD closure because of hypoxemia with right-to-left shunt or right-sided heart failure with left-to-right shunt.