Mitral regurgitation during transcatheter aortic valve implantation: the same complication with a different mechanism

Mitral regurgitation (MR) is a complication that may occur during transcatheter aortic valve implantation (TAVI) in a certain percentage of cases and may require different treatments depending on the mechanism. Our purpose was to describe the occurrence rate of this complication during TAVI with the CoreValve prosthesis, as well as to assess the usefulness of transesophageal echocardiogram (TEE) in the detection of the mechanism of MR.

We analyzed a total of 129 cases of severe aortic stenosis treated with CoreValve prosthesis from June 2008 to October 2011. We defined a significant MR after TAVI as grade III MR or higher, considering either the new appearance of MR or the worsening of a preexisting MR, as assessed by both TEE and angiography. In our series, there was a total of 11 cases of significant MR after TAVI (8.5%). Angiography detected 100% of the MR cases, but was unable to determine the mechanism of MR in any case. TEE, on the other hand, determined 100% of the MR cases, and determined that 1 case was caused by mechanical asynchrony due to a new left bundle branch block, 3 cases were due to an aortic prosthesis impingement on the anterior mitral leaflet, 2 cases were due to the appearance of a systolic anterior movement of the anterior mitral leaflet with dynamic obstruction of the left ventricular outflow tract, 1 case was caused by a commissural tearing of the valve, and 4 cases were explained by a "functional" mechanism, probably due to transient damage of the subvalvular mitral apparatus by the delivery system. All cases had an MR grade II or less as evidenced by transthoracic echocardiography at discharge. Surgery was not required in any case. Knowledge of the mechanism of MR made it possible to provide the best treatment option in each case.

There is a certain percentage of patients treated with CoreValve prosthesis who develop significant MR during the procedure. TEE, unlike angiography, can define the very diverse mechanisms of MR in 100% of cases, and elucidates the best approach to this complication. Surgery was not required in any case.