Ventricular Embolization of Edwards SAPIEN Prosthesis Following Transcatheter Aortic Valve Implantation

Abstract: Transcatheter aortic valve implantation (TAVI) is an alternative therapy in patients with severe aortic stenosis (AS) and high surgical risk. Despite continuous improvements in operators’ expertise and device technology, complications associated with TAVI are common. We present a case in which an Edwards SAPIEN prosthetic valve dislocated to the left ventricular outflow tract with hemodynamic collapse 4 hours following implantation and embolized into the left ventricle (LV) during resuscitation.

J INVASIVE CARDIOL 2012;24(10):537-538

Key words: aortic stenosis, TAVI, TAVR

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Transcatheter aortic valve implantation (TAVI) has emerged as an alternative method to surgical aortic valve replacement for symptomatic patients with severe aortic stenosis and with very high or prohibitive operative risk. Despite being less invasive than open-chest aortic valve replacement, TAVI is associated with the potential for serious complications, such as valve embolization.¹ Valve embolization after TAVI is a life-threatening complication that requires immediate diagnosis and treatment. 

Case Description

A 76-year old male patient with a history of hypertension, diabetes mellitus, severe chronic obstructive pulmonary disease, heart failure, and coronary artery disease presented with dyspnea and in New York Heart Association (NYHA) class IV. The patient was unresponsive to medical treatment. Echocardiography demonstrated a severe calcific aortic stenosis with a 0.6 cm² valve area. The mean transvalvular gradient was 55 mm Hg and left ventricular ejection fraction was 30%. He had a very high surgical risk (Logistic EuroSCORE = 18.35%). The aortic annulus measured 22 mm in diameter in echocardiography.

A 26 mm Edwards SAPIEN prosthesis was successfully implanted percutaneously through the right femoral artery. Postprocedural aortic root angiogram demonstrated mild paravalvular leak and slight inferior placement of the valve (Figure 1). Echocardiography showed a well functioning prosthesis, with an area of 1.9 cm² and a mean transvalvular gradient of 8 mm Hg with a mild paravalvular leak. The procedure was performed under mild sedation. The patient became hemodynamically unstable 4 hours after the procedure. Bedside echocardiography demonstrated that the valve was dislocated with obstruction of the left ventricular outflow tract (LVOT). The device was holding on to the anterior leaflet of the mitral valve and there was severe mitral insufficiency. The patient did not respond to the inotropic treatment and required resuscitation, during which the valve embolized into the left ventricle (Figure 2). The patient improved following the embolization and he was urgently taken to the operating room. The valve was removed through the native aortic valve (Figure 3). The surgical repair was successful and the patient’s functional capacity improved to NYHA class 1 in 3 months.

Discussion

The embolization is primarily due to the malpositioning of the valve, incorrect measurement of the native aortic annulus, incorrect selection of the valve size, or lack of significant valve calcification for prosthetic anchoring. Embolization can occur at the time of implantation if the prosthesis is deployed when the subvalvular annulus or the native leaflets fail to provide adequate fixation. So far, late embolization has not been observed.² Two models of Edwards SAPIEN valve are currently available. The 23 mm valve size is considered appropriate for an annulus diameter of 18 to 21 mm, whereas the 26 mm valve size is recommended for an annulus larger than 21 mm (up to 25 mm). The diameter of the aortic annulus is measured from the transthoracic parasternal or transesophageal long-axis views. Transesophageal echocardiography is now the standard for final determination of the annular dimensions. Proper position prior to the inflation is typically guided by fluoroscopic recognition of calcific landmarks, aortography, and echocardiography. Using a fluoroscopic angulation perpendicular to the valve plane can provide more reliable placement, whereas a non-coaxial position prior to inflation makes correct positioning more challenging. Approximately two-thirds of the stent should be positioned below the plane of the leaflet insertion for optimal positioning prior to balloon inflation. Another reason for embolization of the CoreValve and Edwards SAPIEN valves is severe hypertrophy of the basal septum, which can push the valve superiorly. During placement of the Edwards SAPIEN valve, fast ventricular pacing can be helpful by decreasing the ventricular contractility with a decrease in systolic pressure below 60 mm Hg, otherwise the valve can dislodge into the aorta with more effective ventricular contractility. Embolization to the aorta is well tolerated as long as coaxial wire position is maintained, preventing the valve from flipping over to obstruct antegrade flow. Typically, the valve can be snared or repositioned with a partially inflated valvuloplasty balloon into a stable position in the aorta.³ Embolized valves remain in a stable position with no evidence of strut fractures at mid-term follow-up.⁴ Embolization to the LV is far less likely, but in such cases surgical removal might be the only option.⁵ Embolization into the LV can occur both during transfemoral and transapical approaches.⁶ The interesting feature of this case was the fact that valve embolization occurred 4 hours following the implantation. The multi-slice CT angiogram (Figure 4) demonstrated asymmetric calcification (lack of calcification in one cusp) with slightly lower valve position, both of which could have been responsible for valve dislocation and the resultant embolization with hemodynamic collapse.

Conclusion

There are efforts to develop valves with improved ability to recapture and reposition following deployment. This will clearly be more advantageous compared to the current valves. Improved understanding of the potential complications associated with TAVI might help improve outcomes and allow wider application of this therapy. Development of new tools for the management and, mainly, for the prevention of the complications is advisable. A multidisciplinary team with surgical back-up should be ready during the TAVI.

References

1. Gül M, Türen S, Sürgit Ö, Aksu HU, Uslu N. Acute severe occlusion of the left main coronary artery following transcatheter aortic valve implantation. Anadolu Kardiyol Derg. 2012. doi:10.5152/akd.2012.082
2. Webb JG, Nietlispach F. Implantation of the Edwards SAPIEN Valve. In:  Serruys PW, Piazza N, Cribier A, Weeb JG, Laborde JC, de Jaegere P, eds. Transcatheter Aortic Valve Implantation: Tips and Tricks to Avoid Failure. New York: Informa, 2010:198-207.
3. Masson JB, Kovac J, Schuler G, et al. Transcatheter aortic valve implantation: review of the nature, management, and avoidance of procedural complications. JACC Cardiovasc Interv. 2009;2(9):811-820.
4. Tay EL, Gurvitch R, Wijeysinghe N, et al. Outcome of patients after transcatheter aortic valve embolization. JACC Cardiovasc Interv. 2011;4(2):228-234.
5. Tuzcu ME. Transcatheter aortic valve replacement malposition and embolization: innovation brings solutions also new challenges. Catheter Cardiovasc Interv. 2008;72(4):573-578.
6. Astarci P, Desiron Q, Glineur D, El Khoury G. Transapical explantation of an embolized transcatheter valve. Interact Cardiovasc Thorac Surg. 2011;13(1):1-2.

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From the Department of Cardiology, Istanbul Mehmet Akif Ersoy Thoracic-Cardiovascular Surgery Training and Research Hospital, Istanbul, Turkey.
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.
Manuscript submitted April 23, 2012, provisional acceptance given April 30, 2012, final version accepted May 30, 2012.
Address for correspondence: Mehmet Gul, MD, Department of Cardiology, Istanbul Mehmet Akif Ersoy, Thoracic and Cardiovascular Surgery Training and Research Hospital, Istasyon mah. Istanbul Cad. bezirganbahce mevki, kucukcekmece 34303, Istanbul, Turkey. Email: drmg23@gmail.com