Pre-procedural TTE is a good alternative to TEE in evaluating septal puncture height in Mitra Clip

Introduction: The MitraClip procedure is performed in patients with mitral regurgitation that have contraindications for surgery. The inter-atrial septum is crossed from right to left atrium, thus creating a left-atrial approach to the valve. The optimal height of atrial puncture is 4 cm, which is crucial to the procedure`s success. This is customarily evaluated by a pre-procedural trans-esophageal echo (TEE). Our hypothesis is that transthoracic echocardiography (TTE) is informative enough for this evaluation.

Material and Methods: Retrospective analysis of 113 patients undergoing MitraClip implantation at the Hadassah Medical Center (April 2016 - February 2020), and had both pre-procedural TEE and TTE. We measured the maximal puncture height by TEE (mid-esophageal 4-chamber view) and compared it to maximal septal height by TTE (apical 4-chamber view).

Results: The level of agreement was 62% (70/113) at a cutoff of 4 cm (CI:52.3%-70.9%). In 36.3% (41/113) TTE demonstrated height above 4 cm, while the TEE measurement was smaller. In 1.8% (2/113) the height by TTE was below 4 cm while being higher by TEE. The correlation between TTE and TEE was good, with a Pearson correlation-coefficient of 0.618.
By Bland-Altman analysis (Fig. 1), 106 TTE measurements (93.8%) were within two standard deviations, 6 (5.3%) were above and only 1 (0.9%) were below. Thus, there is a strong quantitative agreement between the tests with no systematic bias.




Conclusions: We found that there is a good concordance between TEE and TTE measurements of septal puncture height in MitraClip. This was mainly apparent in heights lower than 4 cm. In these patients, we recommend performing preoperative TEE for further evaluation. In all other patients with septal height above 4 cm by TTE, pre-procedural TEE can be avoided for this purpose alone.