A hybrid approach to coronary revascularization relieves multi-vessel blockages without spreading the ribs or stopping the heart
BY KIMBERLY MCGHEE
The most feared myocardial infarction, known colloquially as the “widow maker,” occurs when the left anterior descending artery (LAD), which runs down the front of the heart and supplies the front and main wall, is critically blocked by plaque buildup. Coronary artery bypass grafting (CABG) has long been the gold standard for treating blockage of the LAD due to coronary artery disease (CAD), especially in patients with multivessel disease1 or diabetes.2 The CABG procedure with the best survival rates involves harvesting the left interior mammary artery (LIMA), which runs behind the sternum, and grafting it to the blocked LAD in order to restore blood flow.3 LIMA to LAD bypass provides very durable results, with ten-year patency rates of 95 to 98 percent.4
However, traditional CABG requires that the chest be fully open to reach the heart, and then that the heart be stopped during the operation, necessitating use of cardiopulmonary bypass. Several weeks of recovery are required after open surgery. When percutaneous coronary intervention (PCI) with drug-eluting stents began to show similar short-term outcomes as open CABG, many patients opted for the less invasive approach because it could be performed without cardiopulmonary bypass and without opening the chest. For PCI, a catheter is used to unblock the artery and a stent is implanted via the catheter to hold the artery open. Recovery time is shortened from a few weeks to a few days. This approach can also be used in patients who are not good candidates for open CABG. Results are not as durable as with LIMA to LAD CABG, however, and repeated revascularization is often necessary.2 In contrast, PCI has achieved better long-term results than CABG for non-LAD blockages.5
Hybrid coronary revascularization (HCR) maximizes the strengths of both approaches while minimizing their drawbacks. The LIMA to LAD bypass is performed with the help of a surgical robotic system, and then PCI is used to open up any non-LAD blockages. The patient benefits from the durability of the CABG procedure and the superior outcomes of PCI for non-LAD blockages without having to experience the prolonged recovery and surgical morbidity associated with traditional open CABG. A follow-up study of the POLMIDES (NCT01035567) trial, which compared HCR to traditional CABG in 200 patients, found similar rates of survival at five years for the two approaches.5
“Hybrid coronary revascularization is using the best of both worlds to treat coronary artery disease,” says Lucian Lozonschi, M.D., director of surgical heart failure and cardiac transplantation at the MUSC Health Heart and Vascular Center.
Lozonschi is one of the site principal investigators, along with interventional cardiologist Daniel H. Steinberg, M.D., of the Hybrid Coronary Revascularization Trial (NCT03089398), which is randomizing patients with multivessel CAD to either minimally invasive CABG plus PCI or PCI alone. This trial should provide definitive evidence as to which of these modalities is most effective in these patients. The MUSC Health Heart and Vascular Center was chosen as a site for this trial because it has expertise in both minimally invasive (robotic) CABG and PCI. It also offers a hybrid OR that is ideal for such hybrid procedures.
Unlike open CABG, robotic CABG does not require a large incision or opening of the breastbone, and it is performed without cardiopulmonary bypass. For robotic CABG, Lozonschi makes three very small thoracic incisions to enable docking of the robot’s arms and placement of an endoscopic camera. Then, seated at a monitor displaying endoscopic imaging of the surgical field, Lozonschi uses the robot in the harvest of the LIMA. Lozonschi then hand sews the LIMA to the LAD through a mini-thoracotomy (roughly 6 cm) to complete the CABG. Once Lozonschi completes the robotic CABG, Steinberg opens non-LAD blockages using PCI with drug-eluting stents.
Robotic surgery is best performed at high-volume tertiary care institutions by surgeons with specialized training, such as Lozonschi for robotic CABG and Marc R. Katz, M.D., MPH for robotic mitral valve repair (see “A Robotic Revolution” in the summer 2017 issue). The MUSC Health Heart and Vascular Center is one of a handful of heart centers offering both robotic CABG and robotic mitral valve repair.
To watch video interviews with Heart & Vascular Center specialists, including a video with Katz about robotic mitral valve surgery and a video with Lozonschi and Ryan J. Tedford, M.D., about heart transplant, visit the Cardiology page of the MUSC Health Medical Video Center (MUSChealth.org/medical-video).
1. Hillis LD, et al. J Thorac Cardiovasc Surg. 2012;143:4-34.
2. Investigators B. J Am Coll Cardiol. 2007;49(15):1600-1606.
3. Cameron AA, et al. J Am Coll Cardiol. 1995 Jan;25(1):188-192.
4. Tatoulis J, et al. Ann Thorac Surg. 2004 Jan;77(1):93-101.
5. Tajstra et al. JACC: Cardiovasc Interven. May 14, 2018;11(9):847-852.