Usefulness of intraoperative color three-dimensional transesophageal echocardiography for detecting treatable residual mitral regurgitation immediately after mitral valve repair.

Background: Residual mitral regurgitation (MR) immediately after mitral valve (MV) repair is a risk factor for late reintervention. This study aimed to determine the feasibility of color 3-dimensional intraoperative transesophageal echocardiography (3D-IOTEE) for clarifying the mechanism of residual MR and its impact on the conversion rate to MV replacement (MVR).

Methods: Among 767 patients who underwent MV repair at our institute, 92 consecutive patients in whom an immediate second cardiopulmonary bypass (CPB) was performed due to MV repair for residual MR were evaluated. The patients were divided into the re-repair group [i.e. those in whom repair required additional procedures, n = 77 (83.7 %)] and the MVR group [i.e. patients who underwent MVR alone, n = 15 (16.3 %)]. All patients underwent 3D-IOTEE to evaluate the mechanisms of residual MR. The pathomechanisms were classified into the following five categories: Category 1, inter-scallop malcoaptation; Category 2, suture dehiscence; Category 3, prolapse; Category 4, systolic anterior motion of the MV; and Category 5, tethering. Clinical background and outcomes were compared between the two groups based on the five categories.

Results: The rate of MVR conversion by etiology of residual MR after the first MV repair was 68.8 % (n = 11/16) in Category 1; 0 % (n = 0/22) in Category 2; 2.4 % (n = 1/41) in Category 3; 20 % (n = 2/10) in Category 4; and 33.3 % (n = 1/3) in Category 5. Among the 63 patients with Category 2 and 3 etiologies, 62 patients had complete MV re-repair with additional procedures [Category 2, 100 % (n = 22/22); Category 3, 97.6 % (n = 40/41)]. Meanwhile, MVR was performed owing to difficulty in MV repair after the second CPB in 11/16 patients (68.8 %) with Category 1 etiology.

Conclusions: In the assessment of MR, 3D-IOTEE is useful for lesion localization and determining the origin and severity of MR, which are key factors in selecting the optimal surgical approach in patients undergoing re-repair.