THE PLATYPUS REUSABLE STABILISER

The shortcomings of the currently available commercial devices, together with their high monetary and environmental cost, prompted the design of the PLATYPUS REUSABLE STABILISER. We could find no advantage for a suction device over simple mechanical stabilisation. The need for efficient and unobtrusive occlusion of the coronary artery is important and it soon became evident that silastic snares were safe and quick to deploy. This method was further improved by incorporating removable cleats to hold tapes onto the foot. The artery is not only occluded but also elevated into the field. Because the snares are attached to the foot, immobilisation is further improved. The window created by foot is large enough to allow the snares to be placed after it is applied to the heart. Because of the variability of cardiac size and coronary anatomy three different interchangeable feet were designed to greatly increase the choice of stabiliser configuration. To reduce friction, the screw clamps incorporate thrust bearings, greatly increasing their efficiency. In all but a few cases, where the heart is huge, finger tightening is sufficient. If this fails, a large artery clamp can be used for final tightening. The completely reusable device clamps onto any chest spreader <7 mm. thick and has been used in over 200 cases where an average of 3.1 grafts per patient were applied and this represented 91% of all coronary cases; 15% were re-operations.

SURGICAL MANOEUVRES TO FACILITATE BEATING HEART SURGERY

Deep, left lateral, pericardial stay sutures of heavy nylon are essential in most cases. With the heart displaced strongly to the right with the left hand the first suture is placed in the pericardium just inferior to the left inferior pulmonary vein. (This suture can obstruct a dominant circumflex when the LAD is being grafted.) The second stay is placed caudal to the first, as far posterior as possible, close to the diaphragmatic reflection of the pericardium. Variable traction on these stays will rotate the heart into the field for grafting anterior wall arteries. Strong traction enables the heart to be displaced enough to do the marginal arteries. When the lateral wall arteries are to be exposed it is usually necessary to open the right pleural cavity. An additional pericardial incision from the right anterior pericardio-diaphragmatic reflection down, almost to the inferior vena cava, helps the heart to fall back into the right chest. Trendelenberg and right lateral rotation of the table are often required when grafting marginal arteries. To expose the PDA and postero-lateral arteries, steep trendelenberg and traction on the caudal stay suture allow the apex of the heart to be displaced out of the incision to gain easy access to the inferior wall of the heart. To get to arteries near the crux, stays placed either side of the IVC can pull this region quite a long way towards the surgeon.

INDIVIDUAL STABILISER POSITIONS

I prefer to keep the post positioned on my side of the chest spreader for most grafts. The post- rod is slid fully to the left of the surgeon and either the left or center foot is used to graft anterior wall and marginal arteries. With the rod on the surgeon's right and using the right foot, the PDA and postero-lateral arteries are exposed. The post can be put on the left side of the spreader and the left foot used to graft inferior wall arteries, if preferred. This is also a good configuration for the RCA on the inferior surface of the heart. In practice there is a lot of variability because of different heart sizes and positions, but one soon recognises these and adjusts the stabiliser configurations appropriately.