The off-pump technique, also known as OPCAB, is very similar to the conventional Coronary Artery Bypass Grafting (CABG) procedure. OPCAB still utilizes a medial sternotomy, however the important difference is that the cardiopulmonary bypass pump is no longer employed.

Procedure:

OPCAB was developed from the minimally invasive school of thought, so the basic premise is to reduce incision sizes. A surgeon will perform median sternotomy of varying sizes (depending on the physiology of the patient, the smallest incision will be made). Arteries or veins can be harvested from the patients chest wall, arm, and or leg.

Harvesting A Vein From The Leg Movie

To aid the surgeon in operating on the beating heart, drugs such as Adenosine and Esmolol are used to slow the heart rate. To allow for access to the entire heart, there must be a sufficient amount of cardiac displacement. This is accomplished by deep pericardial sutures and the use of specialized instruments to prop the heart in a position that will allow the surgeon to access occluded arteries.

Once within the pericardial sac, sponges are used to reduce free blood in the region being operated on. The sponges also serve as a way to displace the heart, allowing a clear view of the region for anastomosis. With the heart still beating, there is a greater difficulty in performing a bypass on the posterior and lateral walls of the heart. Surgeons have found many ways to stabilize the heart in order to bypass the necessary arteries. Along with sponges, some surgeons will use slings to prop the heart in the necessary positions and then utilize a stabilizer to focus on a particular occluded artery. Biotechnical firms have also developed products such as the Octopus® that help to stabilize pertinent regions of that heart during surgery. Some surgeons will prepare the patient for attachment to the cardiopulmonary bypass pump in case of an emergency or accident that might occur during the operation. This is precautionary and not all surgeons will choose to do so.

 The length of the operation depends on a number of variables. Much like CABG, the number of occlusions can greatly effect the length of time on the operating table. The removal of the cardiopulmonary bypass pump does reduce time since it does not need to be attached and the heart does not need to be reanimated. However, the beating heart must be handled with a great amount of care. To reach an artery on the lateral wall of the heart, the heart must be propped and stabilized, all of which can add to the length of the operation.