Techniques and Instrumentation used to Operate on a Beating Heart
One of the major benefits to the
MIDCAB and OPCAB operations is the elimination of the heart-lung machine during the procedures. However, this is also a major drawback to these off-pump operations because of the constant movement of the still-beating heart. This constant movement causes anastomosis between graft and artery to be more arduous and less precise that those made on a stopped heart during conventional CABG [4]. In order to make this procedure easier and more accurate, a few surgical techniques have become commonplace and several medical-technology firms, such as Heartport, Guidant and Medtronic, have each devised their own unique instrumentation in order immobilize the heart surface during surgery.Loop Sutures
In this procedure, the surgeon passes a suture around the coronary artery - above and below the site of the graft - creating a loop around it. This loop is then held in clamps thereby suspending and immobilizing the area of the graft anastomosis and occluding the coronary artery above and below the anastomosis [4]. This procedure provides the surgeon with a clear operative field that is not flooded with blood.
Objections: During this procedure, the loop suture often strangles the coronary artery and may injure vessel walls.
Special Clamps and Heart Stabilizers
Several medical-technology firms have each devised different specially-designed occlusion clamps that can be fixed to the chest wall in order to immobilize the heart. By applying pressure to the surgical field with the prong-like stabilizer, movement is restricted in the area of the heart between the prongs. This stabilizes the heart within one millimeter of motion thereby enabling the surgeon to operate, while still permitting the heart to beat [1].
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Heartport's OPTrac STILLSITE Stabilizer® (below) is designed with several degrees of freedom for optimal placement and positioning in accessing and stabilizing the coronary arteries [14]. This system is not reusable and sells for around $5000 [5].
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Much like Heartport's system, Guidant's Ultima OPCAB® system (above) offers consistent and reproducible performance, effective vessel stabilization and minimal obstruction of the operative field for enhanced visualization and maneuverability [13]. |
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Octopus Device OCTOPUS®2+ Tissue Stabilization System (right) is Medtronic's innovative contribution to minimally invasive instrumentation. This device has multiple small suction cups that are applied to the heart surface. When suction is turned on, the cups stick to the surface, and hold the heart steady, with movement being less than 1 mm. for each heart beat. This system is reusable and sells for around $10,000 [2] Drug Therapy In addition to the above techniques and technologies, two drugs - Esmolol (a short acting beta-receptor antagonist) and Adenosine (a natural metabolite used in arrhythmia treatment) - have been found effective in slowing, and even temporarily stopping the heart beat for short periods (around 20 seconds) [1]. |
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Click a heart for...
More uses of stabilizers and the Octopus⪚ in OPCAB operations
To see a movie on Off-Pump Coronary Artery Bypass Utilizing the Octopus Tissue Stabilization System (look for "View Movie Clip" link. Requires Quicktime 4.0)
To see a dramatization of using a stabilizer in an OPCAB operation (requires Realplayer)
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