Robotic cardiac surgery - Clinical Tree

Introduction

Cardiac surgery was one of the first surgical specialties that was envisioned to be ideal for robotic surgery. While the breadth of cardiac applications has been not as broad as originally hoped, in some areas it has become a highly successful field of our specialty. As cardiac surgery originally evolved from thoracic surgery, the initial approach to the heart was via large thoracotomies. This was associated with significant issues, including limited access to the required anatomical structures, postoperative pain, and impaired respiratory function. The median sternotomy became the mainstay of cardiac surgical access. This approach gave good access to most areas of the heart. However, exposure of the left atrium (LA) through a median sternotomy remains challenging in a subset of patients. Recovery after median sternotomy can be protracted and there is a risk of significant wound complications. Patients generally experience a 2- to 3-month rehabilitation period, with limitations in daily activities such as driving and lifting no more than a few kilograms. The serious complication of deep sternal wound infection (DSWI) occurs in approximately 1% of patients. The incidence is higher in specific patient subgroups (e.g., patients with diabetes, obesity, or chronic airway disease). Mortality of DSWI may be up to 25%. While infection is less of an issue in the thoracotomy approach, incidence of chronic postthoracotomy pain syndrome may be as high as 30% to 40%.

Cardiothoracic surgeons have attempted many different minimally invasive approaches for procedures on the heart. The aim of these approaches has been to reduce wound complications and hospital length of stay, to allow early return to normal physical activity, and to improve cosmesis, without compromising the surgeon’s ability to perform complex surgical procedures. The safety concerns of performing cardiac surgery via smaller incisions have limited many of these approaches. In some cases, while the incisions have been smaller, there has been no advantage in recovery or cosmesis.

Early iterations of robotic systems were trialed in cardiac surgery but were found to have limited utility. There were concerns over performing cardiac surgery remotely using a bedside console. Further challenges of robotic cardiac surgery included the lack of tactile feedback, initial capital costs of the robot system, and training of the entire operating room (OR) team. The da Vinci Robotic system was used by Carpentier to perform the first robotic mitral valve repair in 1998. Subsequently, the robotic mitral valve repair was championed by Chitwood in North Carolina and was taken up by a limited number of surgeons around the world. While there is a paucity of randomized data, many centers have reported excellent results. Yanagawa et al. performed a nonrandomized study comparing outcomes of open cardiac surgery with almost 6000 robotic cardiac surgery cases. They found a significant reduction in length of hospital stay, morbidity, and mortality compared with nonrobotic surgery.

Robotic surgical techniques have evolved over the last 20 years and have been applied to complex cardiac procedures with efficacy and safety outcomes matching or even surpassing the conventional techniques. Procedures involving the mitral and tricuspid valves, repair of atrial septal defects, removal of intracardiac tumors, and adjunctive procedures such as ablation for atrial fibrillation have been shown to be most suited for the robotic approach. Robotic-assisted coronary revascularization for single-vessel disease involving the Left anterior descending artery (LAD) using the left internal mammary artery (LIMA) has also been successfully applied. Multi-arterial totally endoscopic robotic-assisted revascularization or procedures on the aortic valve have also been reported but remain niche procedures currently. This chapter will focus on robotic mitral valve surgery and robotic-assisted single-vessel coronary artery bypass grafting, which are the two most established procedures within the cardiac surgical specialty.

Robotic mitral valve surgery

The mitral valve is ideally suited for the robotic approach as it occupies a relatively small field at the back of the heart. Viewed from the left atrium, the valve faces the right shoulder. The robotic approach through the right chest allows an excellent visualization of the valve, which, in many cases, is superior to that afforded by the sternotomy approach. The lack of distortion improves the ability of the surgeon to assess the valve, aiding in complex valve repair. The opportunity for all in the operating theater to see the valve repair enables valve repair techniques to be taught more easily. It is common and straightforward to perform additional procedures at the time of robotic mitral valve repair, such as atrial fibrillation surgery, atrial septal defect repair, or closure of a patent foramen ovale (PFO).

Indications

Most patients with mitral valve disease are suitable for a robotic approach. Contraindications are mostly relative, and these are outlined in Table 63.1 . The surgical team’s experience and the degree of these conditions will have an impact on whether to proceed robotically. For example, a patient with single-vessel coronary disease would be suitable for a percutaneous intervention to that vessel and a subsequent robotic mitral procedure, while a patient with multi-vessel disease would be best served by a combined open mitral valve repair and coronary artery bypass surgery.

TABLE 63.1

Contraindications to Robotic Mitral Surgery

Relative Contraindication	Reason
Annular calcification	Difficult to excise calcium and reconstruct
Aorto-iliac disease	Need for peripheral cannulation
Concomitant coronary artery disease	Unable to perform coronary artery bypass grafting
Previous pleurodesis	Access to heart via right chest
Severe ventricular dysfunction	Prolonged operation
Aortic regurgitation	Delivery of cardioplegia Ventricular dilation weaning from cardiopulmonary bypass
Ascending aortic dilation >35 mm	Risk of injury with cross clamp

Anesthesia and monitoring

The patient is intubated with a double lumen endotracheal tube (ETT) to facilitate left single lung ventilation. A right radial arterial line is placed and five lead ECG monitoring is required with electrode placement appropriate for surgical access. Pulse oximetry is via a finger or ear probe. Transesophageal echocardiography (TOE) is required for cannulation, guiding mitral valve surgery and cardiac monitoring.

A superior vena cava (SVC) cannula for upper body venous drainage for cardiopulmonary bypass (CPB) is placed via the right internal jugular (IJ) vein after induction of anesthesia. Ultrasound guidance is used to assess the site and size of the IJ vein and to guide the venous puncture. A 17 Fr cannula is placed percutaneously via the right IJ vein using the Seldinger technique and positioned at the junction of the right atrium (RA) and the SVC. The wire position and the position of the cannula are confirmed with TOE. The cannula is filled with heparinized saline and clamped to prevent thrombus formation.

A Swan Ganz catheter is placed approximately 1 cm superiorly in the same vein. Near-infrared spectrometry (NIRS) monitoring is used to assess calf bed perfusion and cerebral perfusion. External defibrillator pads are placed over the left lateral and the right posterior chest, to enable external defibrillation and emergency cardiac pacing.

Patient positioning

The patient is positioned supine with a 10- to 15-degree roll to the left. This is best achieved via a large gel wedge under the right chest and a smaller pad under the lower back and buttock. A roll is place under the knees to relieve stretch on the back and knees. The right arm is placed on an arm board to achieve access to the lower axilla and lateral chest. Care should be taken to avoid stress on the right shoulder, and the head is placed in a neutral position to avoid brachial plexus injury. The left arm is tucked by the patient’s side. The robotic cart is positioned on the left of the patient.

The most efficient way to perform robotic mitral valve repair is with two operators working contemporaneously. This allows one surgeon to work on the chest and one to set up peripheral CPB via the femoral vessels. This then flows on to the robotic component where there will be a console surgeon and a bedside surgeon. This does underline the importance of a dedicated team to enable this approach.

Cannulation and cardiopulmonary bypass

In order to facilitate small surgical incisions, peripheral cannulation is the mainstay of CPB for robotic surgery. The usual access for this is the right femoral arterial, the right femoral vein, and the right IJ vein. As mentioned above, the right IJ venous cannula is inserted after induction prior to surgical draping.

The femoral access can be either open or percutaneous ( Fig. 63.1 ). The open technique utilizes a 2- to 3-cm incision just above the lower border of the right inguinal ligament. The position can be marked by palpation, or with the aid of ultrasound guidance. This is particularly helpful in obese patients. The ligament is exposed and reflected superiorly with the aid of a self-retaining retractor. This gives excellent access to the common femoral artery and the lower part of the external iliac artery. It is important to cannulate the common femoral artery above the profound femoris artery to minimize the risk of limb ischemia.

Fig. 63.1, Femoral cannulation of (a) femoral artery and (b) femoral vein at the level of the inguinal ligament.

Purse strings are placed on the anterior surface of the artery and the vein using 5/0 proline sutures. These are approximately 8 mm × 4 mm in size. Appropriate size cannulae are selected based on the size of the patient and their vessels. Commonly, a 20 Fr arterial and a 24 Fr multi-stage venous cannulae are used. Systemic heparin is given and an activated clotting time (ACT) is taken.

The femoral vein is cannulated first. A long guide wire is placed into the right atrium and the position confirmed with TOE guidance. The bicaval view on the TOE is the most helpful, with additional imaging of the inferior vena cava (IVC) at the diaphragm sometimes needed. The cannula is carefully advanced into the right atrium approximately 2 cm from the RA-IVC junction. If an SVC cannula via the right IJ is not used, the IVC cannula can be advanced into the SVC to provide complete drainage, which is often possible in patients with small body surface area. The femoral arterial line is inserted next, with the guidewire visualized in the proximal descending aorta on the TOE. The arterial cannula is inserted to a depth of 5 to 10 cm. Consideration should be given to lower limb perfusion, in particular for very long cases. NIRS monitoring is very helpful to monitor the change in perfusion. Optimal lower limb perfusion can be achieved with arterial cannulation in the common femoral artery, which allows collateral circulation via the side branches to provide perfusion for the leg. On occasion, a downstream arterial cannula is required in patients with very small femoral arteries. The authors have also had good experience with the use of a proprietary bidirectional arterial cannula (Bi-Flow, LivaNova) in such settings. Careful imaging to ensure wire visualization and meticulous wire technique is paramount to avoid major and potential life-threatening vascular injury.

Once the ACT has reached 450 seconds, CPB is initiated and the patient cooled to 32°C. It is important to pay close attention to arterial line pressure at all times during the case. This should be less than 300 mm Hg. TOE is used to ensure adequate collapse of the right atrium and absence of aortic injury. A negative pressure of between 10 and 40 mm Hg is applied to the venous reservoir to create vacuum-assisted venous drainage. Kinetic venous drainage is used as an alternative in some centers.

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