THREE SPECIAL TECHNIQUES IN CORONARY ... - Europe PMC

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technique for placement of a drain in the left ventricular chamber via the left atrium. .... nipulation. The vein is thenlooped with silicon-rubber tape (Vessel loop*).
THREE SPECIAL TECHNIQUES IN CORONARY SURGERY J. Ernesto Molina, M.D.

Aortocoronary bypass is a well-defined, operative procedure. Numerous modifications and improvements have been made in this technique during the past few years, and are presented in this report. Since expeditious handling is of the utmost importance in performing this type of surgery, essential measures taken to accomplish this goal include protection of the myocardium from over-distension, prevention of breakage of the fine suture material required for this procedure, and avoidance of trauma to the delicate structure of arterial or venous grafts during their manipulation. Three technical aspects related to these points are reviewed: 1) A special technique for placement of a drain in the left ventricular chamber via the left atrium. 2) The prevention of damage to fine suture material by using a newly modified forceps. 3) The management of vein grafts during their removal from the thighs and legs, as well as during the anastomosis stage. LEFT VENTRICULAR DECOMPRESSION

Sustained decompression of the left ventricle is an important factor in any surgical cardiac procedure that requires working with a fibrillating heart. A well decompressed ventricle prevents the damage that over-distension may cause, i.e., ischemia of the sub-endocardium, hemorrhage in the interstitial spaces, and disruption of the myocardial fibers.2'3 More information is available about the deleterious effect that over-distension of the left cardiac chambers has on the lungs.4'5'6'7 Although transventricular decompression via the apex has been widely used, this method sometimes causes complications, particularly in the coronary patient with friable myocardium. Extra hemostatic maneuvers are often necessary, with consequent loss of time and prolongation of the operative procedure. There is also a risk of ligating coronary artery branches by placing stitches in the area of the apex.8 In order to avoid these problems, transatrial ventricular decompression has been proposed and utilized in many institutions."9 Techniques of this procedure vary from positioning a rigid cardiotomy suction cannula in the atrium, to advancing flexible cannulas of various designs into the ventricular chamber. In order for the left atrial vent to be effective, it should be advanced into the ventricle; otherwise, although it is effective in some situations, often manipulations or positioning of the heart will make the aortic valve incompetent, while the mitral valve remains competent. Left From the Departments of Surgery, United Hospital-Miller Division, Saint Paul, Minnesota and St. Anthony's Hospital, Amarillo, Texas Address for reprints: J. Ernesto Molina, M.D., 1901 Medi-Park Place, Suite 212, Amarillo, Texas 79106

Cardiovascular Diseases, Bulletin of the Texas Heart Institute, Vol. 3, Number 1. 1976

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ventricular distension will then occur. The procedure described in this report has been used consecutively in more than fifty cases without complications, and has provided full decompression of the ventricle in any position. A flexible drain catheter is inserted in the left atrium in the routine manner at the point of entrance of the right superior pulmonary vein. The variant in our technique is that this stage of the precedure is done before the heart is fibrillated. A small atriotomy is made, the blood is allowed to flow out, and the catheter drain is inserted (Fig. 1). At this point, and while the drain is being inserted, it must be connected to low suction in order to prevent an air embolism. As soon as the drain is in the atrium, the right hand of the surgeon is positioned under and around the heart, as shown in the illustration (Fig. 2). The index and middle fingers that pass upwards to the atrioventricular groove posteriorly are easily able to feel the intra-atrial catheter through the thin posterior atrial wall. Upon advancing the catheter with the left hand, it will invariably go across the atrium toward the left atrial appendage (Fig. 2). When the index finger is touched by the tip of the catheter, then the middle finger bends and pushes the catheter gently forward. Since the heart is still beating, the blood in the atrium leads the catheter into the ventricle, crossing the mitral valve (shadowed circle in diagram) without difficulty (Fig. 3). The catheter is then advanced another inch

Fig. 1. Insertion of transatrial catheter via the right superior pulmonary vein. The vent is connected to low suction from the pump oxygenator. Purse-string suture seals any space around the catheter. 80

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Fig. 2. The tip of the catheter touches the index finger that is occluding the entrance to the left atrial appendXage. The middle finger leads the catheSter through the mitral valve.

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Fig. 3. The catheter is now advanced into the ventricular chamber and secured in place with the purse-string suture in the pulmonary vein.

or two, depending on the size of the ventricular chamber. The drain is secured with the purse-string suture placed at the point of entrance into the left atrium. It should be emphasized that the two important details of this technique are: low suction in the drain at the time of insertion to avoid an embolism, and maintenance of the heart beat during the maneuver. The last feature makes the catheter slide immediately into the ventricle. If the heart is fibrillated before placement of the catheter, advancing it into the ventricle becomes hazardous and often impossible. This is probably due to the lack of flow direction from the atrium into the ventricle. Prolonged manipulation ensues with further loss of time. Once the surgical procedure is completed, the drain is removed in the usual way.

This method probably should not be used in cases of ventricular aneurysm because of the theoretical possibility of dislodging thrombi present in the aneurysm during the manipulation, and since the ventricular chamber will subsequently be opened in order to repair the aneurysm.

TAGGING OF SUTURE MATERIAL

The use of fine suture material in coronary surgery is a necessity, and most surgeons utilize monofilament type sutures. Tagging of this material requires soft-j awed forceps, preferebly with a nonmetal surface. Otherwise, the suture material will be flattened, broken or weakened at that point. Even the finest type of "mosquito" forceps does this to the sutures. To overcome this problem, the physicians in some medical centers place pieces of small rubber catheters, or rubber shods, on the jaws of the forceps. Drawbacks to the use of this method are that: 1) extra time is required for the scrub nurse to prepare the forceps; 2) the rubber shods often fall off, or they are so thick that closing the forceps is difficult; and 3) rubber shods do not extend to the entire length of the forceps jaw. We have solved these little problems by utilizing the following procedure: The jaws of the mosquito forceps are dipped in a liquid suspension of latex-rubber material (Plasti-Dip*) that is available in any hardware store. A set of "mosquitos" are prepared by immersing the jaws several times, and allowing them to dry overnight. The resultant cover is firmly attached to the forceps; it has a rubbery consistency, and since it is applied in only three layers of coating, the forceps close easily (Figs. 4 and 5). The suture material does not slip through, no matter how fine it is. A set of four prepared "mosquitos" is permanently included in the tray of instruments for coronary surgery. Since the Plasti-Dip material is resistant up to 500 degrees centigrade, the forceps can be autoclaved with the rest of the instruments. Care should be taken, however, to avoid any pressure from other heavy instruments at the time of sterilization, because the hot metal may make indentation or impression marks on the rubber. Also, the forceps should be left in the open position during this stage to prevent the jaws from sticking together.

*Plasti-Dip International, 6404 Cambridge Street, Minneapolis, Minn. 82

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Fig. 4. Close view of the latex-prepared forceps with the jaws partially opened.

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DISSECTION OF THE SAPHENOUS VEIN GRAFTS Frequently, one is unfavorably impressed by observing the technique used in removing the saphenous veins from the legs-veins that will be used a few minutes later to bypass the most important arteries of the body. There is a significantly high percentage of early and late occlusion rates of grafts in a coronary position to make us aware of the critical value of an intact, smooth, nontraumatized endothelium and intact, smooth muscle fibers. Pulling, tugging and pinching the vein with forceps must be avoided. The friction trauma that results from the use of umbilical tapes has already been shown to be damaging to the endothelium, as well as to the muscular layers of the veins.10"'1 During dissection of the veins, we prefer not to grab or pinch the vessel with instruments. The connective tissue surrounding the vessel is sharply incised and dissected, but the vein itself is never seized. Branches are ligated and divided with minimal manipulation. The vein is then looped with silicon-rubber tape (Vessel loop*) which does not exert friction on the vein tissues. Manipulation is decreased to a minimum, occurring only during the time of the anastomosis, when handling is unavoidable, but even then, the over-and-over pinching must be minimized. It is preferable therefore, whenever possible, to hold the vein only at one point during this stage of the procedure. Vascular surgery has been an achievement of excellence in technique, and that standard can be maintained in such delicate surgery as the coronary artery bypass operation. Three useful techniques are described. REFERENCES 1. Effler DB, Groves LK: Open heart surgery for acquired valvular heart disease. Present techniques and trends. Arch Surg 84:155, 1962

2. Galletti PM, Brecher GA: Heart-Lung Bypass. Grune & Stratton, New York. N.Y., 1966. Pp 239-242 of Chap XV; and 282 of Chap XVIII 3. Kaplan S, Clark LC, Mathew EC, Edwards FK, Schwab L, Hemsworth JA: A comparison of the results of total body perfusion in dogs during potassium citrate cardiac arrest, sinus rhythm and induced ventricular fibrillation. Surgery 43:14-23, 1958 4. Kolff WJ, Effler DB, Groves LK, Hughes CR, McCormack LJ: Pulmonary complications of open heart operations: their pathogenesis and avoidance. Cleveland Clin Q 25:65-83, 1958 5. Kolff WJ, Effler DB, Groves LK: A review of four dreaded complications of open heart operations. Brit Med J 2:1149-1152, 1960 6. Littlefield JB, Dammann JF, Ingram PR, Muller WH: Changes in pulmonary artery pressure during cardiopulmonary bypass. J Thorac Cardiovasc Surg 36:604-615, 1958 7. Muller WH Jr, Littlefield JB, Dammann JF: Extra corporeal circulation. In Pulmonary Parenchymal Changes Associated with Cardiopulmonary Bypass. Edited by JC Allen. Published by Thomas, Springfield, Ill, 1958 Pp 336-341 8. Roberts WC, Morrow AG: Causes of early postoperative death following cardiac valve replacement. J Thorac Cardiovasc Surg 54:422-437, 1967 9. Sproul G, Pinto JR, Trummer MJ, DevirL J: Simplified left ventricular venting. J Thorac Cardiovasc Surg 65:433-434, 1973 10. Urschel HC Jr, Razzuk MA, Wood RE: Long-term follow-up of coronary vein bypass grafts: appraisal of factors influencing patency. In Coronary Artery Medicine and Surgery: Concepts and Controversi.s. Edited by JC Norman. Published by Appleton-Century-Crofts, New York, N.Y., 1975. Pp 619-635 11. Urschel HC Jr.: Coronary bypass using veins: Postgraduate Course in Cardiovascular Surgery, 60th American College of Surgeons Congress, Miami Beach, Fla., Oct 1974

*Med-General Inc., 7851 Metro Parkway, Minneapolis, Minn. 84