Robotic Mitral Valve Surgery

The heart is covered anteriorly by the body of the sternum and the third to sixth costal cartilages of both sides. The coronary sulcus, separating the atria and ventricles, spans from the upper medial end of the third left costal cartilage to the middle of the right sixth chondrosternal joint. The anterior interventricular sulcus spans from the third left intercostal space (ICS) 2.5 cm to the left of the midline to a point 1.2 cm medial to the apex. The aortic valve is at the level of the third ICS behind the sternum. The pulmonary valve is at the level of the left third ICS. The tricuspid valve is behind the sternum at the level of the fourth to fifth intercostal junction. The mitral valve is located behind the sternum at the level of the fourth intercostal junction.

The mitral valve apparatus consists of the anterior and posterior leaflets, two commissures, which are the areas where the anterior and posterior leaflets meet, the mitral annulus, and the subvalvular apparatus, including the chordae tendineae and papillary muscles ( Fig. 21.1 ).

Each leaflet has three segments including the A1 (anterior segment), A2 (middle segment), and A3 (posterior segment) of the anterior leaflet and P1 (anterior scallop), P2 (middle scallop), and P3 (posterior scallop) of the posterior leaflet. The anterior mitral annulus shares fibrous continuity with the aortic valve annulus (left coronary cusp and half of the noncoronary cusp) and is also adjacent to the atrioventricular node and the bundle of His. The circumflex artery courses along the posterior annulus and is at risk of injury during mitral valve repair or replacement ( Fig. 21.2 ). The subvalvular apparatus includes two papillary muscles (anterolateral and posteromedial) and the thin fibrous structures—chordae tendineae—that support both leaflets and prevent leaflet prolapse. The primary chordae attach to the free margin of the leaflets, and the secondary and tertiary chordae insert into the leaflet body, closer to the annulus.

Degenerative, ischemic, rheumatic, and infectious processes are the major causes of mitral valve disease and can affect any component of the valve or subvalvular apparatus. Robotic mitral valve surgery is appropriate for both degenerative and functional mitral valve disease. However, degenerative mitral valve disease is the most common indication for robotic surgery. Furthermore, concomitant left atrial appendage (LAA) closure, ablation for atrial fibrillation, and tricuspid repair can also be performed using the same robotic platform.

Following the 2014 ACC/AHA guidelines, in centers with expertise in both mitral valve and robotic surgery, most patients with severe primary MR with appropriate vascular and coronary anatomy may reasonably be considered for early robotic mitral valve repair, regardless of the complexity of mitral valve disease. Patients should be screened for comorbid conditions that may preclude the selection of the robotic technique. Table 21.1 demonstrates plausible and relative contraindications to robotic mitral valve surgery. However, many of the relative contraindications can be managed to allow a safe robotic mitral valve operation.

Repair techniques in patients with functional valve disease relate to the degree of annular and ventricular dilation, papillary muscle displacement, dynamic cardiac function, and degree of leaflet tethering.

Patients at risk for coronary artery disease should undergo a cardiac catheterization or computed tomography (CT) angiography. Patients with significant risk factors for carotid or peripheral vascular disease should be screened by ultrasound and CT. A right heart catheterization may be indicated for patients who have significant pulmonary hypertension, particularly with depressed right ventricular function. Finally, patients with sternal or thoracic deformities should be evaluated by CT to determine whether robotic instrument trajectories will be compromised. A transthoracic echocardiography (TTE) or transesophageal echocardiography (TEE) study should be performed to confirm the diagnosis and determine the repair plan. TEE is also essential in the operative room to delineate mitral valve anatomy in detail, and intraoperative femoral ultrasound should be peformed to confirm the adequacy of vessels for cannulation.

All patients undergoing robotic mitral valve surgery undergo the following steps:

• 1.

  Patient setup and port placement

• 2.

  Cannulation, docking of robotic arms, and exposure of the mitral valve

• 3.

  Mitral valve surgery, tricuspid valve repair, and atrial fibrillation procedures

• 4.

  Weaning from bypass, decannulation, and closing of incisions