Evaluating optical stabilization of the beating heart

Coronary artery bypass grafting (CABG) is a surgical procedure performed to revascularize the areas of the heart deprived of oxygen by blockages. This procedure is relatively common. Improvement of this form of treatment is the topic of this article. An optical stabilization technique developed with the goal of enabling surgery on the beating heart is proposed and evaluated. The technique proposes that an ECG-triggered strobe light be focused on the surgical site making the heart appear still to the surgeon. The illusion of stillness then allows the surgeon to suture uninhibited by the actual motion. A test apparatus to model the heart was constructed and human-factors testing carried out to evaluate subject performance under conditions resembling those when suturing, with and without this strobe in place. In answer to the specific question of this research, "is strobing of a regular, beating heart beneficial to suturing as compared to suturing under normal lighting conditions?" the answer is "no". This was shown in both the objective and subjective measures. Whereas a strobed heart platform should have been less confusing to the subjects, easier to see, and thereby easier to mark, the opposite was seen. Time to perforrn the test was greater for the test of complicated motion with the strobe than without. Error increased as well. For both regularly lit room tests, subjects had better placement of marks as compared to when they did the same tests under optically stabilized conditions.

Progress in Stabilization: An Overview

Revascularization of the heart is accomplished by connecting the tissue distal to the blockage to an oxygenated blood source with redundant veins (e.g., the saphenous vein of the lower leg) and/or arteries (e.g., the internal mammary artery). As coronary arteries are small (diameters are typically less than 2.5 mm) and heart motion substantial, performing a standard CABG surgery requires that the heart be stopped and the normal processes of respiration and circulation be supplanted through cardiopulmonary bypass (CPB) equipment.