Background
By definition, hybrid coronary revascularization (HCR) encompasses surgical coronary artery bypass, usually of the left anterior descending (LAD) coronary artery with an in situ left internal mammary artery (LIMA) graft, typically performed in a robotic-assisted, minimally invasive fashion, coupled with percutaneous coronary intervention (PCI) to the other (non-LAD) myocardial territories, almost invariably utilizing newer generation drug-eluting stents (DES).
Of all robotic cardiac surgical procedures performed worldwide, approximately 50% are coronary artery bypass operations. The remainder is comprised primarily of mitral valve procedures, whereas robotic-assisted atrial septal defect repair and resection of cardiac tumors constitute less than 1% of total robotic case volume . Robotic coronary artery bypass grafting (CABG) has been consistently in practice for more than two decades, especially for those patients presenting with isolated disease of the LAD. The term, “robotic CABG,” however, can, in and of itself, refer to a variety of different procedures.
As illustrated in Fig. 21.1 , patients can be revascularized using robotic methods whether they have single-vessel (typically LAD) or multivessel disease, with or without the addition of PCI, as needed. Minimally invasive direct coronary artery bypass (MIDCAB) is, by far, the most common variant of robotic CABG performed around the world today, either in isolation for those patients with LAD disease alone, or in combination with PCI, as a component of a more global HCR strategy for those with multivessel disease. By comparison, total endoscopic coronary artery bypass (TECAB) tends to be performed in a smaller number of more dedicated, specialized centers that are particularly interested in, and focused on, this procedure.
Regardless of the specifics of the robotic surgical technique employed, HCR has become firmly established as a safe and viable option for patients with multivessel coronary disease.
Patient selection
The 2012 ACCF/AHA/ACP/AATS/PCNA/SCAI/Society of Thoracic Surgeons (STS) Guideline for the Diagnosis and Management of Patients with Stable Ischemic Heart Disease suggests a Class IIb recommendation for HCR, stating that it may be considered a reasonable alternative to more traditional CABG or multivessel PCI in an attempt to improve the risk–benefit ratio of the procedures . The 2014 ESC/EACTS Guidelines on Myocardial Revascularization confirms the role of HCR as a useful option, especially when multivessel PCI is deemed unsuitable, or when the risk of classic CABG is considered to be prohibitive . The more recent 2018 ESC/EACTS Guidelines further affirm the benefits of HCR for patients with multivessel disease, emphasizing the importance of a collaborative multidisciplinary heart team approach in the revascularization decision-making process .
Robotic MIDCAB, and, as a corollary, HCR, is typically contraindicated in hemodynamically unstable patients, nor does it tend to be appropriate for emergency cases. Patients with diminished respiratory function (who are unable to tolerate single-lung ventilation during the case) are also not ideal candidates for a MIDCAB (or TECAB) procedure and would, therefore, be unsuitable for HCR. Significantly impaired left ventricular systolic function has been regarded by some as a relative contraindication to a robotic surgical approach, presuming, therefore, to also preclude the use of HCR in these cases. However, we have previously reported favorable MIDCAB results in this patient population, suggesting that impaired left ventricular function may not, in fact, be a contraindication to HCR . Although robotic MIDCAB is certainly technically more challenging in the obese patient and has been associated with longer operative times , there is no inherent reason why unfavorable body habitus should preclude HCR, and, indeed, satisfactory outcomes have been described in this particular patient cohort as well . Patients who have had previous cardiac surgery can also potentially be offered a reoperative robotic MIDCAB (and thus possibly HCR) in selected circumstances . Given that HCR, by definition, incorporates a PCI arm, patients who are unable to tolerate the dual antiplatelet therapy that is usually mandatory after coronary stenting are not suitable for HCR and should rather be referred for traditional CABG.
Robotic minimally invasive direct coronary artery bypass—surgical technique
In this operation the LIMA is harvested endoscopically, utilizing robotic instruments, with a subsequent open anastomosis to the LAD being fashioned via a small left anterior thoracotomy, almost invariably “off-pump.”
Our technique for robotic MIDCAB has been described previously . The patient is positioned supine, at the very edge of the operating table, and the left scapula is elevated by a soft roll to facilitate access to the left chest. If done appropriately, this maneuver allows the left shoulder to drop (reducing the potential for subsequent conflict with the robotic instruments) and also helps the intercostal spaces to spread apart. The left arm should fall to the side of the table naturally (making a 45 degree angle at the shoulder), and the left hip should be touching the edge of the operating table.
Selective lung ventilation is a prerequisite for a successful procedure, preferably utilizing a double-lumen endotracheal tube, or, alternately, an endobronchial blocker. After deflation of the left lung, three ports are introduced into the left pleural cavity, under direct vision, typically in the second, fourth, and sixth interspaces ( Fig. 21.2 ), along the anterior axillary line. The pleural cavity is insufflated with carbon dioxide.
The da Vinci robotic system (Intuitive Surgical, Inc., Sunnyvale, California), having been positioned perpendicular to the operating table, is brought into the field and docked ( Fig. 21.3 ).
We prefer to harvest the LIMA as a skeletonized vessel, in its entire length, utilizing the robotic instruments exclusively. Early identification of the phrenic nerve and its course is critical to prevent inadvertent injury. Starting cephalad, the pleura, fat, muscle and endothoracic fascia are all divided, revealing the mammary artery and its accompanying veins. Working sequentially in a caudad direction, the LIMA is exposed all the way to its bifurcation point ( Fig. 21.4 ).
The branches of the LIMA can be dealt with either by cautery, clips, or by harmonic scalpel, according to surgeon preference. Due to the lack of tactile feedback while using the robot, extra precaution should be taken when manipulating the mammary artery, and, consequently, visual cues become significantly more important. Excess tension on the LIMA or surrounding tissues should be avoided to prevent vessel damage.
The pericardium is opened endoscopically, utilizing the robotic instruments, typically over the right ventricular outflow tract, and the LAD is identified ( Fig. 21.5 ).
The patient is systemically heparinized, the distal end of the LIMA is divided ( Fig. 21.6 ), and hemostasis of the mammary bed is secured.
