Iatrogenic Atrial Septal Defect After Percutaneous Mitral Valve Repair With MitraClip: Should We Consider Closing Them Routinely?

Abstract: Percutaneous MitraClip intervention for treatment of severe mitral regurgitation in high surgical risk patients requires large-diameter transseptal sheaths that can result in iatrogenic atrial septal defect (iASD), and its prevalence is higher compared with non-MitraClip procedures. This iASD is not routinely closed because the possible consequences are still not fully understood. However, we believe it is important to identify patients who may benefit from its closure immediately after the procedure to prevent hemodynamic deterioration and long-term negative clinical outcomes. We describe our experience with 2 patients who required iASD closure after MitraClip procedure due to right-to-left shunt resulting from increase in right heart pressures. 

J INVASIVE CARDIOL 2020;32(11):E295-E297. 

Key words: iatrogenic atrial septal defect, percutaneous MitraClip intervention, transseptal puncture

Edge-to-edge transcatheter mitral valve repair with the MitraClip system (Abbott Vascular) has become a safe and widely used alternative for mitral valve surgery in high surgical risk patients. The MitraClip guiding catheter (24 Fr) is commonly introduced via the right femoral vein and requires a transseptal puncture to access the left atrium, leaving an iatrogenic atrial septal defect (iASD) that is larger in diameter than other percutaneous procedures (7-14 Fr), such as pulmonary vein isolation, left atrial appendage closure, or percutaneous balloon mitral valvuloplasty.¹ This iASD is not routinely closed; however, the hemodynamic and functional consequences of a persisting defect are not fully understood.¹ Despite positive short-term effects such as acute left atrial pressure relief, different studies have related the persistence of interatrial shunting to increased mortality, heart failure symptoms, pulmonary hypertension, right-sided heart enlargement, worse tricuspid regurgitation, and higher rehospitalization rates.^2,3

Case Descriptions

We present our experience with 2 patients who required iASD closure immediately after MitraClip procedure. 

Patient 1. The first patient was an 80-year-old woman with permanent atrial fibrillation, severe functional mitral and tricuspid regurgitation, and severe pulmonary hypertension with preserved left ventricular ejection fraction. After discussion by the heart team, the patient was rejected for a high-risk surgery and referred for MitraClip repair. One clip was implanted between the A3-P3 leaflets without incident. After the procedure, the patient suffered abrupt oxygen desaturation. Echocardiographic imaging revealed a right-to-left shunt through the iASD (Figures 1A, 1B) related to increased right atrial pressure due to torrential tricuspid regurgitation. The iASD was successfully closed with a 12 mm Amplatzer septal occluder (Abbott Vascular) (Figures 1C, 1D) and the patient showed immediate hemodynamic improvement. The evolution of the patient was favorable, with no hospital readmissions 8 months after the procedure. 

Patient 2. The second patient was a 79-year-old man with hypertension, diabetes mellitus, permanent atrial fibrillation, and severe mitral and tricuspid regurgitation with severe pulmonary hypertension (Figure 2A). He was accepted for percutaneous mitral valve repair due to a prohibitive surgical risk. Two clips were implanted, the first in a central position and the second medial to the first, with good result. Immediately after the procedure, a large right-to-left shunt was detected (Figure 2B), without oxygen desaturation. We decided to close the iASD due to the risk of difficulty in weaning the patient off mechanical ventilation, as well as our previous experience. A 12 mm Amplatzer septal occluder device was deployed at the iASD (Figures 2C, 2D) without complications. No medical adverse events were reported 3 months later. 

Discussion

The rate of persistent iASD after MitraClip procedures is near 50%.² This rate is higher than non-MitraClip procedures, and is probably related to the bigger catheter size, as a direct correlation exists between catheter size and iASD diameter. 

Different indications have been described for iASD closure, including large iASDs (with unlikely spontaneous closure), large left-to-right shunt, pulmonary hypertension, large right-to-left shunt, severe right ventricular dysfunction, thin/aneurysmal septum, and mobile material on pacemaker leads.⁴

Prophylactic closure of the iASD may not be the best option in all patients, but we believe it is necessary to do a risk assessment and identify those who may benefit from its closure. To recognize these patients in a timely manner, we recommend the use of three-dimensional transesophageal echocardiography to evaluate the shape and diameter of the iASD as well as the direction of the shunt, and to monitor the oxygen saturation to detect hemodynamic deterioration.

Conclusion

In our experience, patients with marked pulmonary hypertension, severe tricuspid regurgitation, and right-to-left shunting (indicative of significantly elevated right heart pressures) are at risk of developing significant hypoxia, and iASD closure should be considered immediately after the MitraClip procedure. 

From the Interventional Cardiology Unit, Cardiology Department, La Paz University Hospital, Madrid, Spain.

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. The authors report no conflicts of interest regarding the content herein.

The authors report that patient consent was provided for publication of the images used herein.

Manuscript accepted April 29, 2020.

Address for correspondence: Ariana Gonzálvez-García. La Paz University Hospital, Paseo de la Castellana, 261. 28046. Madrid, Spain. Email: arianagonzalvez@gmail.com 

1. Hart EA, Zwart K, Teske AJ, et al. Haemodynamic and functional consequences of the iatrogenic atrial septal defect following MitraClip therapy. Neth Heart J. 2017;25:137-142. 
2. Schueler R, Öztürk C, Wedekind JA, et al. Persistence of iatrogenic atrial septal defect after interventional mitral valve repair with the MitraClip system: a note of caution. JACC Cardiovasc Interv. 2015;8:450-459.
3. Toyama K, Rader F, Kar S, et al. Iatrogenic atrial septal defect after percutaneous mitral valve repair with the MitraClip system. Am J Cardiol. 2018;121:475-479.
4. Beri N, Singh GD, Smith TW, Fan D, Boyd WD, Rogers JH. Iatrogenic atrial septal defect closure after transseptal mitral valve interventions: indications and outcomes. Catheter Cardiovasc Interv. 2019;94:829-836.