When the left fails,go right: A bailout technique for complex calcified mitral replacement

Abstract

Mitral valve replacement is challenging in the presence of mitral annular calcification. Passing the sutures from the right atrium to the anterior annulus may serve as an effective bailout strategy.

Graphical abstract

This is a visual representation of the abstract.

Key Points

Severe MAC makes anterior annular suturing during mitral valve replacement particularly challenging.

Right atrial–to–annulus suture passage is a simple and effective bailout technique, improving prosthesis fixation and reducing paravalvular leak.

The risk of conduction injury is significant and requires careful, superficial suture placement.

Introduction

Mitral valve replacement can be technically challenging, particularly in the setting of severe mitral annular calcification (MAC). Various techniques have been described to facilitate suture placement, including extensive debridement, patch reconstruction, Cavitron ultrasound surgical aspiration (CUSA).^1,2 However, securing annular sutures may remain difficult, especially along the anterior annulus due to poor exposure and difficulty to remove calcium. In these patients, passing sutures from the right atrium may serve as an effective bailout strategy.

Methods

Standard right and left atriotomies are performed, and the mitral valve is exposed. Circumferential annular sutures are placed using various techniques (pledgeted sutures, decalcification, CUSA, etc.). From the mid-portion of segment A2 of the anterior leaflet to segment P3 of the posterior leaflet, bulky calcifications can be difficult to remove. In this zone, annular sutures can be placed from the right atrium (Figure 1). Pledgeted 2-0 (26 mm 1/2c Ethibond Excel^®) sutures are passed through the interatrial septum (inferior to the fossa ovalis Figure 2) and then through or just below the mitral annulus, with particular care taken near the coronary sinus (Figure 3).

Figure 1.

Cross-sectional view of the heart: line showing the zone where annular sutures can be passed from the right atrium.

Figure 2.

Right atrial view showing the zone (line) where the stitches are passed, in proximity to the conduction system and the coronary sinus.

Figure 3.

Left atrial view showing 2-0 Ethibond pledgeted sutures passed in A3-P3 region.

The procedure then continues in the standard fashion, with sutures passed through the prosthetic valve and secured. The left atriotomy is closed, followed by tricuspid valve repair and closure of the right atriotomy in the usual manner.

Results

This technique was performed in three patients with severe mitral stenosis associated with very severe MAC (Figure 4). The mean age was 64 years old. The mean cardiopulmonary bypass time was 134 min, and the mean cross-clamping time was 106 min. No intraoperative complications were observed. Transesophageal echocardiography demonstrated no paravalvular leak. Two patients developed complete atrioventricular block that did not resolve after 5 days and required permanent pacemaker implantation. The mean follow-up was 6 months. No paravalvular leak was observed. Neither of the patients who had pacemaker implantation recovered native conduction.

Figure 4.

Computer tomography reconstruction of a patient with severe mitral annular calcifications extending to the anterior annulus.

Discussion

Strategies to address MAC in mitral surgery are diverse. Supra-annular or atrialized prosthesis implantation may help to avoid difficult annular suturing but can be associated with prosthesis malalignment, paravalvular leak, and atrial disruption. Patch reconstruction strategies after extensive decalcification can restore annular continuity but may prolong operative time and increase the risk of atrioventricular groove disruption. Finally, valve-in-MAC techniques are attractive in selected patients but remain limited by the risk of left ventricular outflow tract obstruction, embolization, and paravalvular leak.

Passing annular sutures from the right atrium represents a valuable adjunct in complex mitral valve replacement, particularly when anterior annular exposure and suturing are limited by calcification. This approach offers a more direct trajectory for suture placement. By improving access to the anterior annulus, it facilitates secure prosthesis implantation and reduces the risk of paravalvular leak.

However, the proximity of the atrioventricular node and bundle of His raises concern for potential conduction system injury. This complication is multifactorial, related to calcium debridement on one hand and sutures passing on the other hand. ³ In our limited experience, two patients required permanent pacemaker implantation, underscoring that this risk must be acknowledged and weighed. The balance between achieving optimal prosthesis fixation and preserving conduction integrity should therefore be carefully considered, especially in the A2-A3 zone. Technical factors contributing to conduction disturbances include: large deep bites that come close to the conduction tissue, excessive traction on the septal tissue, and large mattress bites in comparison to interrupted pledgeted sutures. Additionally, shallow suture placement near P3 is essential to prevent injury to the coronary sinus.

Another potential application of this technique is the repair of paravalvular leaks located between segments A2 and P3. In such cases, placing sutures from the right atrium could allow effective treatment of the leak without the need to replace the prosthesis. This technique allows repair of these leaks with a shorter cross-clamp time and limited manipulation of the mitral annulus.

Overall, this technique offers a simple, reproducible, and effective bailout option for challenging mitral valve replacement in calcified mitral valves, bearing in mind the risk for conduction injury. Larger series are warranted to further evaluate its safety and long-term outcomes.