Mitral valve repair

Why are we operating?

Reconstruction of a leaking mitral valve on bypass, resecting or re-suspending the prolapsing segment and reinforcing the annulus with a ring, repair beats replacement when the valve allows it.

Indication: Severe mitral regurgitation from degenerative prolapse, symptomatic or with early ventricular dilatation, ideally repaired before the ventricle pays for the leak.

The operation in 4 steps

1. 01Bypass and exposure

   Sternotomy, cannulation and bypass as for any open-heart case; the heart is arrested and the left atrium opened behind the interatrial groove to display the valve.

   Why: The mitral valve is the deepest structure in cardiac surgery, exposure is half the operation. A still, empty heart and a well-developed atrial opening turn an impossible view into a workable one.

2. 02Valve analysis

   Each segment of both leaflets is tested with a nerve hook against its chordae: which segment prolapses, which chordae are ruptured or elongated, how the annulus has dilated.

   Why: Repair is bespoke; the operation is chosen by the lesion. Carpentier's discipline, analyse first, then reconstruct, is why repair works: the surgeon fixes the mechanism, not the appearance.

3. 03Reconstruction

   The prolapsing segment is resected or re-suspended with artificial chordae, leaflet tissue re-approximated, and a prosthetic ring sewn around the annulus to restore its shape.

   Why: The ring is the keystone: degenerative disease dilates the annulus, and without restoring its dimension every leaflet repair is working against a stretched frame that will stretch further.

4. 04Testing and weaning

   The ventricle is filled to test the repair, the atrium closed, air excluded, and the heart weaned from bypass while transoesophageal echo grades the result in motion.

   Why: The saline test predicts; the echo on a beating, loaded heart decides. More than mild residual regurgitation is fixed now, on this bypass run, because leaving it is the one decision that cannot be revised on the ward.

Danger zones

• Left main coronary artery

  Two territories hang from one vessel; its disease changes the whole operative plan.

• AV nodal artery

  Injury or occlusion at the crux trades a rhythm for an infarct.

• Coronary sinus

  Thin-walled and posterior, easily torn by retraction during mitral exposure.

Anatomy you need

The mitral valve deep in the left heart, with the conduction system kept on: the repair's stitches work millimetres from it.

What can go wrong

• Postoperative bleeding

  Tachycardia first, hypotension late; falling urine output; a distending abdomen or rising drain output.

• Atelectasis & pulmonary complications

  Low-grade fever and mild desaturation in the first 48 hours, especially after upper-abdominal incisions.

• Venous thromboembolism

  Unilateral leg swelling, or sudden dyspnoea, pleuritic pain, tachycardia, sometimes the only sign is unexplained hypoxia.